Page 1

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011

1


2

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011


AN ENGINEER’S VIEW

That Was the Year That Was An interesting year, to put it mildly. How else would one describe a year where the global economy beats all the signs of regressing into a second recessionary phase, the USA and Europe playing dangerously close to debt collapse, the Arabian spring syndrome spreading globally, the biggest earthquake-created tsunami in our history with its subsequent nuclear event, an observable widening of the wealth gap both in SA and internationally, and our own political scenario showing quite clearly government capacity to do anything constructive is deteriorating further.

L

ocally, from the perspective of engineering resources, a somewhat dichotomous situation exists. The scenario would be quite impossible to have envisaged let alone planned. A lot of the manufacturing industry is talking of reaching a point where SA appears to be de-industrialising, Eskom’s six packs under construction are later and later each month, and there is a “shortage” of skilled and experienced engineering resources. The use of the word shortage needs to be qualified as there are many retired or retrenched resources that are fully able to deliver but are overlooked for social or customary reasons of age. Adequate training up of new resources is dismal. The well used metric of

There is a “shortage” of skilled and experienced engineering resources Self-inflicted damage

Engineers per million head of population must make some sense as we are in the lowest league here and I guess it is both confirmed and its impact evident in the abysmal lack of technical resources in government, provincial and municipal structures. PPS recently published a finding that some 600 professionals were leaving SA a month, many of these engineering resources essential to build our own environment. Included in these are mining and project management skills that are leaving our commodities industry to boost those in Australia, Canada and South America in particular. With an estimated R2,5 trillion of mining wealth buried in our SA earth awaiting recovery and even beneficiation, this loss is almost self-inflicted damage. If government does not sort out the noise on the nationalisation issue, more losses will occur through the realisation that it will seriously deplete the mining industry and expand unemployment.

Chris Reay

Chairman of the Working Committee: Communications (SA Institution of Mechanical Engineering)

mentored to become competent and productive resources. Unless the recent strategic advisory and action committees being developed by ECSA, together with the voluntary engineering associations, are able to progress rapidly to a point of active execution, the situation will simply deteriorate further. This requires the essential and proper use of the skills development levies paid to the national skills fund that have accumulated and not been used through sheer bureaucratic lack of vision and mismanagement. Herein lies the opportunity for many retired or semi-retired engineering resources to participate on a paid basis as mentors in properly managed, competency-based outcomes training and development programmes.

Inappropriate CVs

Engineering resources remuneration levels are rising. Supply and demand is driving this as particular positions become seriously underprovided with candidate options. How should a business that requires the right people in the right place at the right time go about recruiting resources? When supply is erratic or constrained, then focus on the constraint and subordinate other activities to it. Find the buffers to protect the constraint from starvation or blockage. A supply buffer will be the provider who has access to the best database and network of resources and who can filter out the signal from the noise of the conventional practice of multiple inappropriate CVs from multiple providers all drawing from the same pool. Change HR’s customary structures. Engineering business should look hard at their people procurement practices.

We are producing many graduate engineers, technologists and technicians who are unable to usefully progress into positions where they are trained and THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011

3


4

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011


November/December 2011  VOLUME 61  NUMBER 11

Contents

On the cover: John Thompson www.johnthompson.co.za

Cover Story

29 New Trends in Ducting

9 Combustion of Biomass on a Chaingrate Stoker

Bearings & Lubrication

Monthly Column 11 Working Under Water

Steam, Turbines & Boilers

Copyright

All rights reserved. No editorial matter published in “SA Mechanical Engineer” may be reproduced in any form or language without written permission of the publishers. While every effort is made to ensure accurate reproduction, the editor, authors, publishers and their employees or agents shall not be responsible or in any way liable for any errors, omissions or inaccuracies in the publication, whether arising from negligence or otherwise or for any consequences arising therefrom. The inclusion or exclusion of any product does not mean that the publisher or editorial board advocates or rejects its use either generally or in any particular field or fields.

33 Growth in Centralised Lubrication 35 Smearing the Hard Stuff

Regulars

15 Special Vessels Made Locally

3 An Engineer’s View

POWER GENERATION TODAY

6 Institution News

21 Clarification on Local Content Target 23 Power Generation News

13 SAINT

HVAC 27 Clearing the Smoky Air

19 SAPMA 25 Nuclear Institute (SA Branch) 37 Market Forum

The monthly circulation is 4 242

Produced by:

Official Publication of THE SA INSTITUTION OF MECHANICAL ENGINEERING

PROMECH PUBLISHING, P O Box 373, Pinegowrie, 2123 Republic of South Africa Tel: (011) 781-1401, Fax: (011) 781-1403 Email: editorial@promech.co.za Website: www.promech.co.za

and endorsed by:

Managing Editor Susan Custers Editor Kowie Hamman Advertising Louise Taylor Advertising: Power Generation Today Mark Bennett Circulation Catherine Macdiva DTP Zinobia Docrat Disclaimer

PROMECH Publishing and The South African Institution of Mechanical Engineering as well as any other body do not take responsibility for the opinions expressed by individuals.

Printed by: Typo Colour Printing, Tel: (011) 402-3468/9

 CORROSION INSTITUTE OF SA  SA PUMP MANUFACTURERS ASSOCIATION  SA VALVE AND ACTUATORS MANUFACTURERS ASSOCIATION  THE SA INSTITUTE OF TRIBOLOGY  NUCLEAR INSTITUTE  SA INSTITUTE FOR NON-DESTRUCTIVE TESTING  NATIONAL SOCIETY OF BLACK ENGINEERS  INSTITUTE FOR CERTIFICATED MECHANICAL AND ELECTRICAL ENGINEERS  SOUTH AFRICAN ASSOCIATION OF CONSULTING ENGINEERS  ASSOCIATION OF SOCIETIES FOR OCCUPATIONAL SAFETY AND HEALTH

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011

5


THE SA INSTITUTION OF MECHANICAL ENGINEERING

Council 2011/2012 Office Bearers

President .................................................. G Barbic (George) Vice President .............................................. D Findeis (Dirk) National Treasurer ............................... KK Nyangoni (Kudzai)

Branch Chairpersons

Central ...................................................... M Cramer (Mike) Eastern Cape ................................................ W Rall (William) KwaZulu/Natal ................................................. J Moto (John) Mpumalanga Highveld.............................. L Odendaal (Louis) Western Cape ........................................... Dr D Blaine (Debbie)

In-House Workshop Opportunities and Advantages

Portfolios:

Communications/Strategic Planning/ Specialist Group..................................................CD Reay (Chris) Young Engineers Forum................Prof B Collier-Reed (Brandon) Education: Universities of Technology............... E Zawilska (Ewa) Membership .................................................... E Zawilska (Ewa) Professional Development Programme..........M Black (Malcolm) Technology Programme ................................. SZ Hrabar (Steve) To be confirmed....................................................A Roos (Andre) To be confirmed.........................................G Bartholomew (Bart)

Chief Executive Officer: Vaughan Rimbault National Office Manager: Anisa Nanabhay

PO Box 511, Bruma, 2026 Email: info@saimeche.org.za Website: www.saimeche.org.za Membership: Central, Eastern Cape, Mpumalanga & KZN: membership@saimeche.org.za Membership: Western Cape: saimeche.wc@vodamail.co.za

Alstom Power Service SA Babcock Africa Limited Bateman Engineered Technologies Bosch Projects Fluor SA GEA Air-cooled Systems Hansen Transmissions SA Hatch Africa Howden Power Howden Projects Industrial Water Cooling

Osborn Engineered Products SA Rotek Engineering RSD a division of DCD-Dorbyl S.A.M.E Water Sasol Technologies SEW Eurodrive Siemens SNC-Lavalin SA Spicer Axle SA Spirax Sarco SA Thyssenkrupp Engineering Transvaal Pressed Nuts & Bolts

Ultra-Flow Engineering Services MBE Minerals (SA) (Pty) Ltd (previously KHD Humboldt Vital Engineering Wedag SA) Weir Minerals Africa Megchem Eng & Drafting Services

6

Winder Controls

THE SOUTH AFRICAN MECHANICAL ENGINEER

T

he advantages of hosting an in-house workshop include: • key staff remaining available on site in case there are problems on the plant,

• savings on venue and travel costs,

Tel: (011) 615-5660, Fax: (011) 388-5356

Company Affiliates

Amongst other training activities, during 2012 the National Events Department will focus on providing in-house workshops to corporations wishing to reduce the impact on operation resulting from staff being off site.

VOL 61

• surety that the event in question will not be cancelled through lack of delegate bookings on ‘public’ events, which outcome may cause disappointment to booked delegates wishing to acquire CPD credits. These cost savings enable SAIMechE to offer inhouse event clients a reduced fee. Furthermore, such events offer both the client and SAIMechE the opportunity to hold activities tailored to their specific needs. To date SAIMechE has provided in-house training for BHP Billiton, Continental Tyres, Engen, Eskom, Nestle, PetroSA, Tongaat-Hulett Sugar and Unilever. Altogether, 303 delegate days of attendance have been recorded. Topics covered have ranged from Capital Budgeting for Projects, Root Cause Failure Analysis, Lubricants and Oil Sampling, Improving Plant Safety and Design by Understanding Legislation & Process Safety, Pump Technology, and various Steam-related workshops. Corporations wishing to hold one or more of SAIMechE’s 51 standard workshops on site may contact national events manager, Linda Robinson on (031) 764-7136 or linda@saimeche.org.za. Companies with specific training needs are invited to phone Linda to discuss a customised in-house workshop programme. SAIMechE - contributing to the productivity of your business through enlightened decisions and successful solutions.

Nov/Dec 2011


THE SA INSTITUTION OF MECHANICAL ENGINEERING

Annual Gala Dinner Dance “On Saturday 22 October, the central branch of SAIMechE hosted their annual gala dinner dance, at The Wanderers Golf Club in Johannesburg. The event was once again well attended and thoroughly enjoyed by all. The chairman of central branch, Mike Cramer welcomed everyone and introduced the MC for the evening, Harry Rosen, of 2KG Training. An address was given by Dr Joe Roy-Aitkin of Eskom, entitled “The Role of the Engineer in Eskom today”. Eskom and DRA Mining were both Platinum Sponsors and Vital Engineering was a Bronze sponsor. SAIMechE would like to extend their grateful appreciation to these sponsors for their generosity.The band for the evening was Havana Gas who had everyone dancing the night away. Spot prizes were awarded as well as a prize for the best “Rock & Roll” couple, which went to central branch committee member Carel Kruger and his wife.”

Mike (Chairman CB Committee) & Evie Cramer with their son, Eli and his wife Shani, in South Africa from Israel

Stephen & Esther Murefu – DRA – Platinum Sponsor

Carel & Theresa Kruger – SAPPI Paul & Leandra Naude – from Esteq

Lister Sinclair (Hatch) & his fiancée, Deirdre Ferreira

Joe Roy Aitkins from Eskom – Platinum Sponsor Itumeleng Pitiri (Sasol) & his fiancée, Lerato Mopeng

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011

7


8

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011


COVER STORY

Combustion of Biomass on a Chaingrate Stoker John Thompson, a name synonymous with boilers in South Africa, have been burning a variety of fuels successfully in a number of process applications using their fully-packaged, Europac firetube boilers with modified Thompson Triumph chaingrate stokers. These boilers are capable of producing saturated steam up to pressures of 20 bar when burning a waste by-product.

T

hese applications are not limited to the process industry and in the field of power generation John Thompson is currently commissioning a bagasse-fired co-generation boiler at a local sugar mill. The project incorporates a new 105 t/h boiler and a new 25 MW extraction/ condensing turboalternator. The power plant is designed to provide process steam and power to the factory and to export excess power to the national grid. In order to provide sufficient biomass during the off-crop, the bagasse is supplemented with cane ‘tops and trash’.

Other fuels

John Thompson (JT) is one of a few boiler manufacturers in the world with an in-house technical capacity (facilities & engineers) providing in-depth boiler development. With the experience

The power plant is designed to provide process steam and power to the factory and to export excess power to the national grid gained over many years in the combustion of coal and a variety of waste and biomass fuels; which includes bagasse, peach stones, macadamia nut shells and sunflower husks, a logical step was to develop a boiler for wood by-products and wood-waste. With its higher volatiles and

lower calorific value, burning wood waste inside a water-cooled combustion chamber came with a new set of challenges for optimised combustion. The JT Boiler Development & Test Centre with its fully operational boiler is the ideal place for testing these fuels as the test facility is situated on the factory premises and the various modifications required during the development phase could be implemented by JT’s engineers. Although a number of JT boilers have been burning biomass for many years in places as far afield as Indonesia in South East Asia and several countries in sub-Saharan Africa, industry is constantly looking for “greener” fuels with more efficient combustion. JT’s development programme has kept pace with these demands with the development of the Europac range of boilers which incorporate numerous modifications to the boiler, stoker, draught plant and the Micropac boiler management system. Having achieved the desired results with efficient coal combustion, focus at the request of some leading companies in the food and beverage industry, has shifted toward biomass.

Modifications

Pomace and wood by-product pellets were obtained for testing, discharged into the fuel storage bunker

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011

9


COVER STORY

apparent during the tests which were performed under dry conditions. The wood pellets tested had a volatile content of 70% which resulted in good ignition of the fuel. Due to the even size grading of the pellets and proper control with the Micropac boiler management system, the air flow and hence combustion across the width of the stoker was exceptionally uniform. The fuel was clean burning for the duration of the test period without clinker formation or fouling of the reversal chamber tubeplate. The boiler was able to achieve an output of 70% of its coal-fired rating.

and then fed to the stoker hopper via an inclined screw conveyor. During testing the boiler was started firing on wood pellets using standard operating procedures. After some modifications to the stoker and draught plant, the boiler was brought up to pressure using the Micropac boiler management system within approximately 5 hours from a cold condition.

Although the tests were done under controlled conditions, JT is currently burning bagasse, wood by-product pucks as well as sunflower husks successfully in real factory and process applications.

Various combinations of stoker speed and stoker modifications were investigated to achieve optimum combustion. Fuel handling equipment was designed for minimum degradation of the product and, in fact, none was

10

THE SOUTH AFRICAN MECHANICAL ENGINEER

www.johnthompson.co.za

VOL 61

Nov/Dec 2011


MONTHLY COLUMN

Working Under Water Building industrial pressure vessels is a speciality governed by very strict standards and codes. But to design and make a pressure vessel used for human occupation is highly specialised indeed, undertaken by a few select engineering companies in the world.

the diver to stay under for several hours and therefore commercial diving is distinguished in that it requires breathing specific mixtures of gases through an umbilical cord from a controlled source. “To lower a diver to his level of work, be it for welding, inspection or NDT work, he needs a launch-and-recovery system which lowers him down and lifts him out of the water again,” explains Mike. “Depending on how deep he has to go, the diver either needs air, or mixed gas or needs to be saturated with

T

he only company in South Africa in this business is Unique Hydra in Cape Town. To find out more “SA Mechanical Engineer” speaks to Mike Iles, one of the Mike Iles of Unique Hydra in Cape Town directors. “Although we design, manufacture and service hyperbaric chambers systems for the medical industry, our main focus is pressurised vessels for the commercial diving industry,” he says. “This ranges from a simple cage system to deeper diving in a wet bell system and, for real deep diving, the saturated system where divers remain in the system for three weeks at a time.”

The diver either needs air, or mixed gas or needs to be saturated with a gas mixture Commercial diving

Unlike when using gas bottles on the back, commercial diving requires A model of the integrated saturated diving system a gas mixture with a high helium and very low oxygen content. “The depth determines the size of the launch and recovery system,” adds Mike. “For depths of up to 50 metres we have a steel basket which is lowered from an A-frame by a man-riding winch. This system has high safety factor requirements such as an 8:1 safety factor on the main wire while everything on it is duplicated, the winch, the braking system, the hydraulic power packs and so on. It is equipped with emergency gas cylinders in case something goes wrong with the driver’s breathing apparatus.”

Air requirements

The 12-man SAT system made by Hydra – a complete diving unit

As soon as divers are required to go deeper than 50 metres, the breathing air demand changes which requires a more sophisticated diving platform. “In this case, we remove the nitrogen to avoid the ef-

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011

11


MONTHLY COLUMN

to a pressure equalling the diving depth at which he worked. He can then be treated by a medical doctor to remove any air bubbles in his blood which may have formed during the incident.”

Saturated systems

Hydra’s flagship product is a complete saturation diving system they manufacture to take divers to 300 metres where pressure on the vessel is up to 30 bar system. Designing such a system must be any mechanical engineer’s dream as it is totally self-sufficient allowing a team of divers to remain in a saturated diving condition for 25 days before they go into a five-day decompression cycle. Sophisticated air scrubbing units for helium recovery, waste water treatment plant, airconditioning systems, Inside the SAT unit is the galley with the sleeping quarters at the back. Divers live in this communication systems, compressors, generators and all sorts of hydraulic capsule for 25 days at a time under the same pressure as the depths they work at power packs, make up the system. There’s even a voice scrambler to correct the divers’ voices which become high pitched due to the high fect of the diver becoming ‘drunk’ and disorientated helium content in the air they breathe. from a nitrogen build-up in the body,” says Mike. To get rid of the nitrogen, helium and a percentage How it works of oxygen is mixed in according to the depth being “Basically, a team of divers in an encapsulated pod worked at. The deeper you go, the less oxygen you is lowered to working levels under water where they want in the air mix. can operate for a shift of several hours,” explains Mike. “Instead of their coming up and decompressA complete saturation diving system they manufacture ing, a slow process that takes several hours, the pod is brought up to the surface after each shift to take divers to 300 metres and connected to an integrated unit consisting of For this level, a wet-bell launch-and-recovery system two or three other pressure chambers. is used. It incorporates a dome filled with a pocket of air containing the mix required for a specific working depth. The diver is lowered to working level where, wearing a helmet with a tethered excursion umbilical attached to the main cord, he can swim out of the dome to do his work. This cord supplies the diver with air, communications and a camera feed. Mike adds, “We can even fit a hot water system for very cold working conditions whereby warm water is pumped down the umbilical to flow through the divers’ suit to keep him warm.

“The divers move over to these chambers which serve as their living quarters and are shared between 9 to 12 divers working on the job,” adds Mike. “Three fresh drivers who have now rested for two shifts then get into the pod and go down immediately to continue work on the seabed while the others sit back, clean up, eat and rest - all the time in an environment with the same air mix and pressure as when under water. These chambers, which are normally placed on the deck of a ship, have all the creature comforts of normal living quarters.

Medical

“We’ve just delivered a large 12-man unit for a local commercial diving company based in Cape Town,” says Mike in conclusion. “Such a unit is usually containerised to make it portable and easy to assemble on different platforms. In addition to the chambers it comes as a complete unit with a control room and machine room housing all the machinery such as compressors, air purifiers, generators and so on built into containers so that the modules can be arranged to meet available space on the decks of different ships.”

“While inside the dome the diver can remove his helmet to take a rest and talk to one or two other divers there with him. We have various models to accommodate up to three divers at the same time.” By law, commercial divers need to have a decompression treatment facility within a certain kilometre range of where they operate. “In case of a diving incident which can result in nitrogen narcosis or diving ‘bends’ there has to be a treatment chamber which is essentially a pressure vessel system we design and manufacture specifically for this purpose,” explains Mike. “The diver is put into the chamber which is then blown down with the same air mix

12

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Mike Iles, Unique Hydra, Tel: (021) 534-3600, Email: mikei@hydra.co.za

Nov/Dec 2011


SAINT

Feedback

On 1 November 2011 there were 168 days left to the start of the biggest event for the science of Non-destructive Testing (NDT). the local organising committee (LOC) would like to give some feedback on the development to date so that all engineers and technicians can get their plans into place to partake in this prestigious event.

O

n 14 October 2011 the “soldout” signs went up for the exhibition. The marketing team managed to sell all the available exhibition space six months ahead of the conference, an indication of how sought-after the world conferences are to the suppliers to the industry. 95 exhibitors from all over the world, including 22 from Manfred Johannes South Africa, have booked their place in the exhibition and are looking forward to showcasing the latest developments in NDT to the world. On 15 October 2011 the deadline for submission of abstracts for inclusion in the technical programme came around and we are happy to report that to date 420 abstracts have been submitted. The LOC reviewed the abstracts and the authors were notified of the acceptance of their papers on 15 November 2011.

A Nobel prize-winner

In addition it has been confirmed that Prof. Harald Kroto, a Nobel prize-winner in Chemistry, has agreed to attend the conference and to read a paper on his work. Also five plenary speakers, who are renowned personalities in the NDT and engineering world, have agreed to deliver presentations and last but not least more than 25 eminent overview speakers, who will lead in the respective technology sessions, have confirmed their attendance. All that remains is that the engineering fraternity for South Africa plans their year in such a fashion, that the attendance of the 18th WCNDT from 16 to 20 April 2012 at the ICC in Durban, is a non-negotiable event. This is an opportunity to become conversant with the latest developments in NDT at your doorstep and it is guaranteed that the conference will carry three CPD points for the ECSA registrations for the year 2012. Please make use of this unique and prestigious opportunity to be part of the biggest NDT event in the world, which is staged every four years and now for the first time in South Africa. See you all there! Manfred Johannes President of the 18th WCNDT Robin Marshall, Tel: 011 719-5717, Fax: 086 582 8509, Email: saint@saint.org.za

O

n 14 October 2011 the “sold-out” signs went up for the exhibition. The marketing team managed to sell all the available exhibition space six months ahead of

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011

13


14

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011


STEAM, TURBINES & BOILERS

An autoclave in Cyclotherm’s workshop

Special Vessels Made Locally Like steam boilers, autoclaves are highly specialised pressure vessels built strictly to certain standards and codes, not only for effective functioning, but most importantly, to ensure the safety of people and equipment.

W

ith a 40-year track record of literally thousands of boiler installations and an ever- growing number of autoclave systems, all completely manufactured locally, Cyclotherm (SA) continues to add to its product line-up. “SA Mechanical Engineer” speaks to managing director, Donald Mac Jannet, at Cyclotherm’s headquarters in Wynberg, Johannesburg.

The art of making an autoclave lies in the complex doorlocking mechanism to seal the unit “Lately we’ve seen an increase in the autoclave market, especially for the tyre manufacturing industry for which we’ve just manufactured a number of autoclaves of various sizes,” Don says. “Control technology for autoclaves has changed somewhat over the last couple of years and we’ve included these improvements in our latest designs. The fact

Donald Mac Jannet, managing director of Cyclotherm

that we’re now the preferred supplier for Michelin tyres in South Africa indicates that our design is superior with a proven track record in the tyre industry.

OTR tyres

“We have built many autoclaves in the past, but only recently ventured into autoclaves bigger than two metres in diameter,” adds Don. “The OTR (off the road) tyre industry uses a three metre diameter autoclave for the retreading of OTR tyres and when we realised that no-one else makes this size locally, we decided to start working on the design of a larger diameter autoclave, especially as we already have the manufacturing capability in-house.” The art of making an autoclave lies in the complex door-locking mechanism to seal the unit. Although Cyclotherm has already perfected the basic technology for this, the new design has to be

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011

15


STEAM, TURBINES & BOILERS

retreading OTR tyres. In the past, they’ve had to import the equipment or they’ve endlessly tried to fix or recondition old equipment until it is no longer viable to use”

Features

Don says they have built over a hundred autoclaves, both electric and steam, for a wide range of industries throughout South Africa and the rest of the continent, including industries such as retreading, mining, timber curing, rubber and composite materials curing, agriculture, and millboard manufacture.

Boiler under construction

The mobile boiler house leaves our factory as a portable container and is simply connected to the electricity, fuel and water supply at the other end to become a fully operational unit certified in terms of materials stresses and engineering specifications. “Once our engineers are satisfied with all the parameters, the design is certified by a third party inspection authority before we start manufacturing,” says John. “Although it’s not a huge market, there are quite a few companies involved in

A cyclotherm installation

“Our autoclaves have been developed out of extensive and proven experience that has established this product range as a standard in the industry,” he adds. “They are purpose-built for electrical and steam heating applications and design features include a hinged door and loose ring door-securing device developed by us to ensure perfect pressure retention and long seal life. Smooth operation of the door enables opening and closing by one person with minimal physical effort while all autoclaves are fitted with a door safety device which prevents the door from being opened while the chamber is still under pressure.”

Composites

The aeronautical industry extensively utilises autoclaves

16

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011


STEAM, TURBINES & BOILERS

for the curing of composite components used in aircraft. For example, all the composite components of an entirely locally-built UAV (unmanned aerial vehicle) launched recently, were all manufactured using autoclaves manufactured by Cyclotherm. “We’ve also seen an increase in sales to the rubber curing industry,” Don says. “For example, we recently installed another autoclave system at one of the foremost conveyor equipment suppliers in Johannesburg which uses rubber liners on their bulk materials handling equipment.” Cyclotherm has no fewer than 18 boiler models which can run on oil, gas, coal or a dual-fired system. This flexibility extends to a vast range of fuels including natural gas, sewage gas, Sasol gas, LP gas, producer

The mobile boiler concept where the boiler is built into a container

coming in from all corners of Africa. “Our concept of a mobile boiler house originated from the need to build boiler plants that had to be moved around to other locations on a regular basis, in a cost-effective way without the need for special technicians to do the installation,” explains Don. “The mobile boiler house leaves our factory as a portable container and is simply connected to the electricity, fuel and water supply at the other end to become a fully operational unit.” Inside the ‘box’ the standard steam plant consists of a boiler, sized between 235kg/hr to 1 565kg/hr, a fuel tank, water tank, blow down gas, heavy furnace or coal tar fuels, Sasol waxy oils, diesel, illuminating paraffin or any of the light distillate fuels. In capacity the boilers range from 235 kg of steam per hour to 11 735 kg of steam per hour. Don is working on new economiser technology which promises to bring about a significant energy saving, but he’s keeping everything under wraps until all testing has been finalised.

Mobile boilers

Although it has not taken off to the extent which Don originally expected, the concept of a mobile boiler house is still doing well with regular orders

Don is working on new economiser technology which promises to bring about a significant energy saving tank, water softener plant and dosing unit, an electrical DB board and lighting, steel grid floors and a PRV station assembly if it is required. “We’ve even built a few mobile boiler houses where this capacity was doubled by placing two boilers in a container,” says Don in conclusion. Don Mc Jannet, Cyclotherm, Tel: (011) 887-8410, Email: don@cyclotherm.co.za, Website: www.cyclotherm.co.za

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011

17


Reassuringly Comprehensive. WEG Group

The reassurance of a global brand won’t have escaped you. For almost anything in electrical engineering processes this is where you’ll find a proven, world–class answer from ZEST WEG. So, whether your design task involves materials handling, water treatment, power generation/distribution or transformers, from manufacturing to installation and commissioning, you’ll find the best solutions right here – all under one roof. The right supplier. The right solution.

Peripheral 2011213

That’s good engineering.

0861 00 ZEST www.zest.co.za

18

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

WEG Group Nov/Dec 2011


SAPMA

Pimp My Pump This monthly column, submitted by SAPMA (SA Pump Manufacturers Association) guides and advises readers on the in’s and outs of the pump world.

P

ractical considerations for the use of AC variable speed drives & motors

1. Current distortion on the VSD output.

VSD compatible motor selection

3. Reduced torque at increased speeds. (N>Nnominal)

Not all standard AC motors are truly suitable for VSD applications. There are two main issues to consider:

2. Reduced cooling at reduced speeds. (N<Nnominal)

2. Motor insulation – VSD output pulses have peak values (Vpeak) and sharp rise times (dv/ dt) far above the normal grid 50Hz sine wave. These values as produced by the VSD and the corresponding motor insulation must be known and must be compatible.

The basic operating principle of all standard VSDs is to convert the 50Hz AC supply voltage to DC and then convert the DC back to AC. For this reason VSDs are sometimes referred to as frequency converters. The conversion from DC back to AC uses a system of calculated and controlled pulses referred to as Pulse Width Modulation (PWM). This system allows the VSD output frequency and voltage to be controlled, thereby controlling motor speed. However the PWM results in current distortion. This can be seen in Fig. 1 below. The current distortion causes additional heat in the motor.

Motor heat rise

Reduced flux

1. Motor heat rise – a motor on a VSD will run at higher temperature than a D.O.L. motor. It is important for this additional heat rise to be minimal and to be precisely known.

It is well known that motors in VSD applications will have a higher heat rise than normal and must therefore be de-rated for VSD applications. The reasons and details of this are however not well known. There are three reasons for increased heat rise:

A motor depends on a shaft mounted cooling fan on its non drive end for cooling air flow. When the motor runs at speeds slower than the normal 50Hz speed, this fan turns slower and the motor has reduced cooling. As a result, the motor thermal capacity and hence its allowable output torque is reduced. Motor torque is dependant on magnetic flux. Flux is a part of motor design and is directly proportional to the ratio of voltage to frequency. For a 400V 50Hz motor this ratio is 400/50 = 8. For a 525V 50Hz motor this ratio is 525/50 = 10.5. At full speed, eg, 1460RPM on a 4 pole motor, the VSD output is full voltage and nominal frequency. This gives full flux and torque. Above this speed, the voltage cannot increase but the frequency does. This results in reduced flux and consequently reduced torque. See Fig. 2 (overleaf).

Harmonics

Figure 1

To an ever increasing extent, users are becoming aware of the reality and negative impact of VSD induced harmonics. These harmonics are inherently a result of the VSD method of operation. The initial rectification of the AC supply voltage to DC causes an irregular or distorted current to be drawn. This causes harmonics. All standard VSDs produce very similar levels of harmonics. Harmonic current are currents at multiples of the fundamental frequency. THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011

19


SAPMA

5% voltage THD. Fortunately this level of distortion is seldom reached. It is important to note that current THD and voltage THD are at very different values.

Accurately predict

Figure 2

For example the 5th harmonic is at 5 x 50Hz = 250Hz. These harmonics cause additional heating in the supply transformer and at sufficiently high levels may cause interference with other equipment. Most large end users find a harmonic level that causes 5% distortion on the voltage acceptable, ie,

Also it is possible to accurately predict the harmonic distortion prior to proceeding with an installation. Fig. 3 shows an example of such a calculation. Once this calculation has been made, the user can determine if the harmonic distortion level will be acceptable or not. The simplest method to reduce the harmonic distortion is by adding line reactors. Fiona Knell, Tel: 072 889 2789, Email: fiona.sapma@ vodamail.co.za, www.sapma-sa.co.za

Figure 3

20

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011


POWER GENERATION

Produced by: PROMECH PUBLISHING, P O Box 373, Pinegowrie, 2123 Republic of South Africa Tel: (011) 781-1401 Fax: (011) 781-1403 Email: editorial@promech.co.za Website: www.promech.co.za Managing Editor Susan Custers Editorial Kowie Hamman, Eleanor Seggie Advertising Mark Bennett, Louise Taylor Circulation Catherine Macdiva DTP Zinobia Docrat/ DonovanVadivalu Disclaimer PROMECH Publishing does not take responsibility for the opinions expressed by individuals. Printed by: Typo Colour Printing Tel: (011) 402-3468/9

Clarification on Local Content Target A manufacturer of multi-megawatt class wind turbines, has called for clarification on the Department of Energy’s threshold for local content for onshore wind renewable technologies, saying it is “unexpectedly low”.

R

ob King, MD of DCD-Dorbyl, says in anticipation of future participation in the manufacture of components for wind energy enterprises, as well as nuclear power plants, the Group has made a massive investment into technology and skills through its subsidiary Isivunguvungu Wind Energy Converter (I-WEC).

Onshore wind energy technologies with a local content of more than 60% Copyright

All rights reserved. No editorial matter published in “Power Generation Today” may be reproduced in any form or language without written permission of the publishers. While every effort is made to ensure accurate reproduction, the editor, authors, publishers and their employees or agents shall not be responsible or in any way liable for any errors, omissions or inaccuracies in the publication, whether arising from negligence or otherwise or for any consequences arising therefrom. The inclusion or exclusion of any product does not mean that the publisher or editorial board advocates or rejects its use either generally or in any particular field or fields.

“In terms of wind energy technologies alone, we have invested R75-million to create local capacity to produce wind turbines, not only to world class standards, but to the state-of-the-art in the global wind energy technology field,” Rob says. “DCD-Dorbyl is capable of manufacturing the complete wind energy converters for onshore wind energy technologies with a local content of more than 60% — more than double the target that appears to be stipulated in the adjudication of the Department of Energy’s request for proposals documentation. “We have approached the Department for clarification to determine if benefit will be given to tenders with higher local content than the target set. “We believe in the future of the South African wind energy sector and the significant investment we have made in order to participate in this exciting new industry

bears this out. In fact, the more we look at the value chain associated with wind turbine manufacture, the more opportunity we see for industries other than ourselves to benefit. We want to be a willing partner with government to establish a successful wind energy sector and in so doing, create much-needed jobs.”

Dedicated facility

I-WEC was founded during 2009 in Cape Town, to manufacture 2,5 MW wind energy converters. A wind energy converter comprises a tower base, an 80 metre tower, a wind

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011

21


POWER GENERATION

turbine unit and three blades per turbine, each 50 metres in length.

operation is complemented by in-house erection, operating, service and maintenance facilities.

The engineering and design of the turbines is in accordance with the proven and certified technology provided by Aerodyn Energiesysteme GmbH in Germany, a leading specialist in wind energy conversion technology. I-WEC has acquired licences and technology transfer agreements from Aerodyn to manufacture 2,5 MW wind turbines and rotor blades and will manufacture the blades in a new dedicated facility, assemble the wind turbine units in an existing facility and fabricate the steel towers completely within its various plants. I-WECâ&#x20AC;&#x2122;s complete manufacturing

First-of-production

This will make I-WEC the first South African manufacturer of multi megawatt wind energy turbines including rotor blades. The company is an active member of the South African Bureau of Standards Working Group for the Adoption of International Wind Energy Standards (International Electrotechnical Commission [IEC] standards). I-WEC is currently demonstrating to representatives of Aerodyn and an independent German authorising body that it is capable of erecting and commissioning a wind turbine, using a first-of-production (in South Africa) wind energy converter.

A rotor blade manufacturing training facility to equip local people 400 jobs

Once this localisation certification is in place, personnel will be trained in the operation and maintenance of the turbines, as part of DCD-Dorbylâ&#x20AC;&#x2122;s Private Benefit Organisation, in which the company has made an investment of R35-million into training and development in selected industry sectors. I-WEC estimates that in the medium term it will be able to create about 400 permanent jobs within the operation. I-WEC has also initiated a discussion with the German government in regard to the possible establishment of a rotor blade manufacturing training facility to equip local people with the new skills required to participate in this new sector and provide them with recognised certificates of competency.

In earnest

The certification of the local production processes required to manufacture the 2,5 MW wind turbines is the final stage in the lead-up to full scale manufacture by the end of 2011. The first 2,5 MW wind turbine will be completed in February 2012 and five more will be assembled over the next 15 months. Thereafter production will begin in earnest at a rate of 50 units per annum in year one, 100 units in year two, ramping up to an ultimate output of 200 wind turbine units per annum for the local and international wind energy conversion markets. DCD-Dorbyl, Rob King, Website: www.dcd-dorbyl.com

22

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011


POWER GENERATION NEWS

Network repair

The National Department of Public Works has awarded Ai-Tec a three-year contract for the repair and maintenance of refrigeration systems, gas cooking equipment and reticulation networks for the Queenstown and East London region. “This multi-million Rand contract, which also encompasses a 36-month maintenance programme, applies to correctional institutions in the Eastern Cape, in Fort Glamorgan, King Williamstown, Burgersdorp, Queenstown, Dordrecht , Stutterheim and Whittlesea,” says Arnold Retief, a director of Ai-Tec, specialists in the design, manufacture, installation and maintenance of industrial and commercial equipment. “Apart from improved health, safety and running efficiencies of these gas, refrigeration and reticulation systems, a critical feature after completion of this project will be substantial energy savings.” Cold and freezer rooms will be upgraded and gas cooking equipment and reticulation will also be restored. Installation and refurbishing, which commenced in September, is due for completion in 2014. Ai-TEC manufactures a wide range of equipment for commercial and industrial applications, that include hospitals, correctional service institutions, hotel and boarding schools.

Rehau Raugeo PE-Xa probes were chosen for the heat store because they can easily withstand the high water temperatures of up to 85ºC without any deterioration in performance or risk of damage. The inherent durability of the PE-Xa material means it is also highly resistant to nicks or scratching during installation or while in the ground. Rehau Polymer, Theda Botes, Tel: (011) 201-1300, Fax: (011) 201-1350, Email: theda.botes@rehau.com, www.rehau.co.uk

The company’s specialist services, which uphold stringent quality, health and safety specifications, include waste management, energy production and steam reticulation throughout Africa and into global markets. Advanced Industrial Technology (Ai-Tec) Arnold Retief, Director, Tel: 0861 248-320, Email: arnold@zsteam.co.za, www.ai-tec.co.za

Energy efficiency tax incentives

Ground source heat store

Braedstrup Fjernvarme is the Danish site for Europe’s largest seasonal ground source probe heat store combined with a solar thermal energy system. In phase one of the project, 50 Rehau Raugeo vertical PE-Xa probes have been installed across an area of approximately 225m² area at a depth of 47-50m to store the heat generated by a 16 000m² solar thermal panel installation. In summer, the hot water circulates at up to 85ºC within the probes and acts to heat up the surrounding ground and create a gigantic heat store. In winter when heat is required for the town’s district heating scheme, the stored heat is transferred back to the circulating water and extracted via a heat pump. Using a compact geothermal borehole field, the ground is activated to store heat throughout the summer season and operates much more efficiently than the insulated surfacemounted water storage tank which was used previously. The solar thermal heat is currently providing district heating to 1 200 homes but, because the system has the capacity for up to 3 600 homes, the excess heat is stored for later use. In phase two of the project, planned for 2012-2013, a total solar heating area of 60 000m² will be installed with 250-350 probes drilled to store the heat.

The South African government is offering tax rebates using section 12i, ‘the Industrial Policy Project Investment incentive for manufacturing-related projects with a 10% energy demand reduction component’, and more recently the proposed 12L ‘Regulations on the allowance for energy efficiency savings’. Both these tax incentives are sections of the Income Tax Act of 1962 and are used as an instrument by government to encourage sustainable development of the economy. In terms of these tax allowances, industry will be entitled to claim a rebate for energy efficiency savings. The proposed regulation for 12L sets out the process for determining the quantum of energy efficiency savings, and requirements for claiming the proposed tax rebate, which stipulates a prerequisite that energy savings reports have to be compiled by registered measurement and verification (M&V) professionals. As from 1 January 2012, this prerequisite will pertain to the 12i incentives as well. The South African National Accreditation System (SANAS) was tasked by government to create an infrastructure in order to accredit M&V bodies for tax incentives. To ensure that M&V services and service providers are credible, trustworthy and transparent, an independent professional body was established in the form of the Council of Measurement and Verification Professionals of South Africa (CMVPSA), a chapter of the Southern African Association for Energy Efficiency (SAEE). Karel Steyn, board member of the

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011

23


POWER GENERATION NEWS

CMVPSA says, “The CMVPSA was established to take on the responsibility of registering and governing M&V professionals in South Africa.” The South African National Energy Development Institute (Sanedi), the organisation currently tasked with the responsibility of adjudicating, evaluating and supporting 12i projects to the Minister for the Industrial Policy Project Investment incentive, is set to undertake a similar task for the 12L incentives according to the regulation published for comment. Adjudication of the 12L tax incentive claims will be based on the reports compiled by registered M&V professionals to ensure accurate and transparent claims. Organisations wishing to claim incentives are therefore required to appoint an M&V professional as part of the requirements of the regulation. The technical and academic requirements for registration with CMVPSA are of such a standard that the Sanedi adjudication committee has decided to only consider section 12i tax rebate claims where CMVPSA registered M&V Professionals have participated in the project up until 1 January 2012, similar to the requirement of 12L. Section 12i has been in operation since 2009, and its claiming process will remain as is until 1 January 2012, after which date this new requirement will come into effect. Southern African Association for Energy Efficiency, Yolanda de Lange Tel: (041) 367-1041, Email: delangey@mweb.co.za

Training in Zimbabwe

South African construction industry training company, BCA Training, a Binnington Copeland & Associates related company, has completed a training programme for Zimbabwe Power Company (ZPC) personnel who are expected to be involved with the Chinese on the expansion of the Hwange Power Station. ZPC is currently in advanced discussions with the Chinese over a 600 Mw expansion at the coal fired Hwange Power Station as well as the a 300Mw expansion of the hydro station at Kariba South at a potential cost of US $1,58 billion. The training, which was to acquaint the power company staff with the international FIDIC forms of contract, was conducted by Binnington Copeland managing director, Chris Binnington, an internationally recognised authority on FIDIC. According to Chris, in event of the of these projects receiving the green light from the Zimbabwe government, the projects would probably be designed, built and financed by the Chinese but ZPC will insist on using the internationally recognised form of contract and FIDIC is the favoured option. BCA, Chris Binnington, Cell: 082 807-4053, Email: cdb@bca.co.za

Our bevy of beauties bedevilled by burglars, butchers and bikers would like to wish all our readers and advertisers a happy and safe festive season. With “B” the theme of this years staff party we’d like to remind you all to ‘B’ safe, ‘B’ happy, ‘B’ good and ‘B’ back next year to share in our exciting industry.

Standing from left: Eleanor Seggie (Blonde Bombshell); Belinda Siegruhn (Biker); Jacqueline Nene (Boy); Di Bluck (Blindspot); Raymond Campling (Bank Robber); Susan Custers (Bipolar); Louise Taylor (Burn Survivor); Catherine Mahamo (Black Cat); Kowie Hamman (Butcher); Zinobia Docrat (Blue Bunny). Seated from left: Lelanie Lane (Bee); Surita Marx (Burka); Colleen Cleary (Bok Fan); Yolanda Flowerday (Butterfly).

24

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011


NUCLEAR INSTITUTE (SA BRANCH)

“Irrevy” to the good, calls from the bar. ‘Anything exciting happen at the power plant today, dear?’ I once wrote an article for a newspaper explaining the then new seven point International Nuclear Event Scale (INES). This had been introduced by the IAEA to provide some means of conveying to the media the severity, or otherwise, of reported nuclear accidents. Needless to say, Chernobyl and Fukushima have both come in at Level 7. Below Level 4, significant ‘accidents’ become less significant ‘incidents’. The editor was happy with the article and published it alongside a small cartoon showing a pathetic three-eyed mutant troll. ‘Everything was wonderful’ this sad creature explains ‘but then we had this little nuclear incident’.

Assorted mutants While blowing dust off my technology bookshelf a few days ago, I came across a slim volume unopened for at least a decade. ‘Irrevy – an illustrated view of nuclear power’, by John W Gofman.

T

he cover carries the cartoon reproduced here. An Eskimo trudges through snow towards the distant igloo. ‘It’s a rugged life’ he muses ‘but it’s free from the hassles of civilization’. Meanwhile, the falling snow-flakes are all little atoms - radioactive fall-out. The arch nuclear opponent of the 1970s was Professor Ernest Sternglass, vilified by his own health physics profession, beloved of the nuclear critics. His mantle passed to physicists John Gofman and Arthur Tamplin. John W died in 2007. He seems to have possessed a nice sense of humour, strange ideas about nuclear energy notwithstanding. Another of his cartoons shows a nuclear boardroom. The communications manager is thumping the table. ‘First off’ he’s saying ‘we have to convince the people that good health isn’t everything!’ Another shows the power station manager struggling home through the front door in a terrible state, clothes torn, hair awry, face blackened. Staring eyes. His wife, already one martini

Anything exciting happen at the power plant today, dear?

Nuclear communications people come off particularly badly. One cartoon in my small but valued collection has a PR guy standing on site inside a tall glass box. He’s wearing a suit and a fixed Jimmy Carter grin. The caption reads ‘In case of emergency, break glass’. Elsewhere in the collection, a PR official is addressing a group of journalists on a beach. On the horizon is a ship identifiable as the Pacific Teal, one of the Pacific line ships custom-built to carry new fuel, reprocessed plutonium and nuclear waste between Europe and Japan. ‘We can absolutely assure you’ he says ‘there is no possibility whatsoever of radioactive leakage’. Behind him on the sand stands an aggrieved group of two-headed penguins and other assorted mutants. Even stone-age BC gets into the act. He’s found a good spot downstream of the local nuke and has just caught a big one. ‘Great!’ he says ‘They come out ready cooked!’ On another occasion he has made iced-lollies with water taken from the same spot. ‘Look’ he says ‘lollies that glow in the dark!’ The only vaguely pro-nuclear cartoon I have ever come across shows a cocktail party. The room is full of party-goers holding glasses and things on sticks. All of them are distinctly upset and they are all sprouting little wings. They have evidently just been vapourised and have gone to Heaven. The host is standing on a chair calling out to them. It’s all right, everyone. It wasn’t a nuclear explosion after all. Just a gas leak!’ Happy Christmas! John Walmsley “Irrevy” – an illustrated view of nuclear power, by John W Gofman. Published by the Committee for Nuclear Responsibility, Main P.O.B 11207, San Francisco, CA 94101.’ Copyright © 1979 by the Committee for Nuclear Responsibility. All rights reserved. First edition. Library of Congress Card Catalogue #78-73212 International Standard Book Number 0-932682-00-6

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011

25


26

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011


HVAC

When people’s lives are at stake, a ventilation fan isn’t just any fan, but should in fact be a smoke certified fan manufactured by a reputable manufacturer who has made it in accordance with the prescribed National Building Standards of South Africa.

T

his, however, is not always the case. Many local building contractors are gambling with people’s lives to save money. The fan manufacturers who go to great lengths and cost to produce fans which comply, are fed-up with this state of affairs and have joined forces to nip this evil in the bud.

Smoke inhalation

“SA Mechanical Engineer” speaks to Andy Crowe, national sales manager of Donkin Fans in Port Elizabeth, about how the new building regulations affect the HVAC industry in respect of fire and smoke control equipment. “The number one cause of deaths related to fire is smoke inhalation,” he says. “An estimated 50 to 80 percent of fire deaths in the world are as a result of smoke inhalation injuries rather than burns.”

Not immune

“It is disappointing to see that these deaths occurred in buildings where priority should have been given to safety due to the mobility of the people inhabiting them,” adds Andy. “Fire fighters are certainly not immune to the danger, often thrusting themselves into the hazard. Although we have no current statistics for South Africa, about 3 000 fire fighters are injured each year in the USA alone, and these are highly trained and equipped professionals.” The original building regulations recognised that in any fire, smoke is probably the greatest danger to life and therefore smoke control and dispersal measures are a priority. Measures include ventilation and extraction systems, compartmentation by means of smoke control doors and automatic controls on airconditioning systems to stop the passage of smoke through the system from one part of the building to another.

Smoke is probably the greatest danger to life and therefore smoke control and dispersal measures are a priority Most of the fatalities occur in public buildings such as shopping malls, night clubs, movie theatres and hotels. Andy adds, “Recent events in South Africa have cast a shadow on our safety record. Besides the recent fire at the Umhlanga Hospital in KZN when two people died from smoke inhalation, most recently 18 people died in a fire at a retirement home in Nigel while a further four people succumbed to their injuries subsequent to the fire.

Andy Crowe, national sales manager of Donkin Fans in Port Elizabeth

Who’s responsible?

For instance, the old regs specified that any room with a floor area larger than 500 m² had to be provided with a system of mechanical smoke ventilation, either through roof ventilators or open windows or panels. “However, nobody was sure about who was responsible for what in terms of applying these regulations. The application of National Building Standards now goes a long way to becoming more definitive and begins to lay down the levels of responsibility,” explains Andy. “The regulations are now more in line with world best practice. The basics are still the same but clarification of certain points has been addressed. THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011

27


HVAC

No excuses

“We have now given our product suppliers more defined requirements in terms of equipment,” adds Andy. “Most importantly, the regulation is definitive enough to ensure that all levels involved in the process take responsibility. Without this, you can’t apply ‘the buck stops here’ principle.

It’s not enough to turn a blind eye and say because we were not involved or were not informed, we do not care “For instance; when requesting smoke fans, the consultant will require the equipment to comply with BSEN12101 Part 3,” explains Andy. “If this instruction is given to the product supplier, then he or she is responsible for ensuring that the smoke fans meet the requirements of the law which include the fact that the appointed manufacturing facility must be ISO9001 approved, the units supplied must have been type and performance tested correctly and certification must be available if requested. The same procedure applies to natural ventilators, ducting, dampers, smoke barriers and so on.”

28

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nipped in the bud

To assist industry in this exercise, the SASVA (South African Smoke Ventilation Association) was founded last year with Andy as the current chairman of the association. “Membership is open to companies involved in design, contracting, installing, product, commissioning and maintenance of HVAC systems,” explains Andy. “The aim of the association is to promote the ideals of a competent, knowledgeable body of professionals in the field of smoke control engineering and to assure customers, consultants and end users of the benefits of dealing with members of the association. We also provide technical knowledge, expertise, and training. “A database of approved suppliers is currently being compiled and assistance is given to companies to ensure compliance,” Andy says in conclusion. “Many may ask why bother? We reply, why take a chance? The responsibility and ultimately the liability, lies with us all. It’s not enough to turn a blind eye and say because we were not involved or were not informed, we do not care. If there are practices going on that do not conform, we all have the responsibility to get involved. The saving of just one life is incentive enough.” Andy Crowe, Donkin Fans, Tel: (041) 409-1431, Email: andy.crowe@donkin.co.za, Website: www.donkin.co.za

Nov/Dec 2011


HVAC

New Trends in Ducting Round is so much better than rectangular in many ways. In fact, most of the world has steadily switched to round ducting rather than the traditional rectangular channels for conveying air. In South Africa the take up has been slow, most likely because the advantage of round ducting isn’t widely known.

S

A Mechanical Engineer” speaks to Gert Wibbelink, managing director of Airconduct in Pretoria, a company which specialises in all types of ducting for the HVAC industry. “We’re currently on a drive to promote the round ducting we manufacture as standard stock items in a whole range of diameters, lengths, bends and related fittings,” he says. “Only in very rare cases is space too confined for spiral ducting, in which case rectangular has to be used, but the advantage of round ducting is set to make it the first choice in ducting.”

The advantage of round ducting is set to make it the first choice in ducting Round ducting

Gert Wibbelink, managing director of Airconduct

Airconduct makes use of an imported machine from Switzerland to manufacture spiral ducting. “A strip of 137 mm wide steel is rolled into a tube and mechanically sealed in one continuous process,” explains Gert. “It’s a very airtight system that can take pressures up to 1 500 Pascal. With various dies we can make tubing from 100 mm to 1 600 mm in diameter using materials varying from

The Spiral ducting Airconduct manufacturers

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011

29


HVAC

that rapidly turns out duct lengths of up to six metres.” Apart from the spiral tubeformer, they also make use of a Gore locker machine from Switzerland which is used to make single flanges, double flanges and also lock seams for the production of air tight joints in segmented bends, reducers, end caps and offsets. Although not in South Africa yet, Spiro makes the machinery for oval ducting, yet another option which is not as efficient as round ducting, but is better than rectangular ducting when space is an issue. Some mines in Canada have exploited the versatility of this system to actually make the ducting underground, saving many hours and the cost of transporting pre-fabricated ducting down the mine.

Stronger sections

The extended manufacturing area

The smaller surface areas of round, compared with rectangular, allow less heat loss or gain and are therefore more energy efficient 0.4 mm to 1.7mm in thickness. With a strip-feed speed of 70 metres per minute, it’s a quick system

30

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

“Spiral ducting has lower initial installed costs than rectangular duct,” says Gert. “The shape results in lower pressure drops, thereby requiring less fan input energy to move the air and, consequently, smaller equipment. The shape also has less surface area and requires less insulation when externally wrapped”.

Nov/Dec 2011


HVAC

“Spiral duct is available in longer lengths than rectangular duct, thereby eliminating costly field joints,” adds Gert. “In addition, the spiral lock-seams add rigidity and therefore the spiral duct can be fabricated using lighter gauges than longitudinal seam ducting. Operating costs are also lower because the smaller surface areas are round, compared with rectangular, allow less heat loss or gain and are therefore more energy efficient. Generally the seams and joints are more tightly sealed resulting in less leakage and thus less wasted energy.”

Good looking

The acoustic performance of round duct is superior because its curved surfaces make for less breakout noise. “These ducts not only perform better, they look better,” says Gert. Many architects and designers are using the aesthetically pleasing shapes of The Spiro machine used to make round ducting round as unique and integral elements in their designs. Finally, round duct can help probreeding ground for bacterial growth. mote healthier indoor environments. The fact that there’s less surface area, no corners and better Since we last visited Airconduct’s factory in Silvertonairflow reduces the chance of dirt and grime dale, the workspace has been significantly enlarged accumulating inside the duct and it becoming a allowing ample space for both the rectangular and

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011

31


HVAC

Round ducting in Airconduct’s own factory

spiral duct production lines to operate sequentially. “We have increased under-roof storage space specifically to store the spiral ducting components which we manufacture as standard stock items,” explains Gert. “You can’t do that with rectangular ducting as each order is usually made up of customised components for a specific installation. Obviously stock items translate into yet another saving which we can pass onto our clients.”

Streamlined production

Whether round ducting will overtake rectangular remains to be seen, but Gert will continue manufacturing both systems while there is a demand. “Most rectangular ducting systems used to be manufactured in complete sections, resulting in large metal units taking up a huge amount of space,” remarks Gert in terms of improvements they’ve made in the production of rectangular ducting.

Making them too big causes problems in getting them through openings, especially in multi-storey high-rise buildings “Such units are difficult to handle during transport as well as on site. Making them too big causes problems in getting them through openings, especially in multi-storey high-rise buildings. Now the long straight pieces are made in L-shapes with profiled edges that make assembly on site a matter of snapping the bits together to produce a rectangular duct channel. The L-shape pieces are neatly strapped onto a pallet, making handling at both ends a simple forklift or crane task.” Gert Wibbelink, Airconduct, Tel: (012) 804-0626, Email: gert@ airconduct.com

32

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011


BEARINGS & LUBRICATION

Growth in Centralised Lubrication

I

n a similar evolution, centralised lubrication systems for plant machinery are steadily growing, particularly in South Africa, as more and more end-users come to grips with the fact that they’re actually saving money by investing in automated systems where necessary.

Disillusioned and disappointed

However, an automated lubrication system isn’t necessarily the answer to all bearing failure problems on a plant. The root cause of bearing failures in machinery could very well stem from something else and so an automated system isn’t going to solve the problem. All that happens is that the plant operator is left disillusioned and disappointed with these systems.

Automated centralised lubrication systems for vehicles were fairly new just the other day, but now you’d be hard-pressed to find a heavy duty vehicle without one.

“SA Mechanical Engineer” speaks to lubrication specialist, Jan Backer, Lubrication Solutions Manager at SKF, to find out more. “Many make the fatal mistake of trying to solve bearing failures by immediately installing an automated lubrication system while the root cause could be seals or Automated lubrication systems are just one of the tools which help to something else altogether,” he says. “For this ensure the longest life and least reason we have specialist engineers who are unexpected breakdowns of machinery trained to audit a plant in order to determine due to bearing failure the real reasons behind failures and, where appropriate, to design a customised lubrication solution for each individual situation.

Specialist engineers who are trained to audit a plant in order to determine the real reasons behind failures A big project

SKF’s lubrication division in South Africa is relatively new, but the engineers have already been put through their paces in introducing and practically applying the principles of this extended service, backed by a vast range of tried and tested equipment, locally. “We’re currently busy with what is to be a first for SKF South Africa in terms of the size of the centralised lubrication project,” Jan says. “We are fortunate to have been involved right from the start, designing a lube system for all the conveyor pulley drive systems on one of the new power stations being built. Installation of the systems, covering over 500 lubrication points with a progressive feeder system, will start early next year from the base we’ll be setting up on site.” This project, like many other local contracts, promises to pave the way for SKF engineers to showcase the huge value of automated lube systems. “There is a general misconception that SKF is just a bearing supplier, but projects like this will help to show industry that we’re in fact a solutions provider who can assist in finding and solving the root problems around bearings,” Jan elaborates. “Automated lubricaTHE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011

33


BEARINGS & LUBRICATION

of each individual plant to find the right customised solution for each one. “Once we’ve completed the analysis, we design the system accordingly by grouping lube points into manual serviceable points, by grades of standard and special greases. Finally we automate the lubrication of points that are critical or inaccessible,” explains Jan. “You can even group points that need very specific dosages. For example, in a dangerous or hard-to-reach area, you may suggest fitting a small pump with a grease reservoir that only needs to be refilled every six months lubricating only 20 points, while 200 other points can be greased manually.”

A lube system for all the conveyor pulley drive systems on one of the new power stations being built

Lube systems can be configured in custom-engineered designs to lubricate from single machines right through to a complete process plant. “In some applications you might, for example, use a small, one to five kg, dedicated reservoir pump containing food grade grease that might need refilling more often,” elaborates Jan. “For the remaining let’s say 500 points, you then have the centralised system’s master lines for each grade of grease running from the lube room to the specific groups of points throughout the plant.

ROI

Jan Backer, Lubrication Solutions Manager at SKF

tion systems are just one of the tools which help us to ensure the longest life and least unexpected breakdowns of machinery due to bearing failure.”

Automated lubrication systems are just one of the tools which help us to ensure the longest life Analysis

Everyone knows that bearings have to be lubricated with the right type of lubricant, the right amount and at the right time. To achieve this, there are specific maintenance solutions to ensure optimum bearing life in machinery. But, because each plant is different to the next, it requires a proper analysis

34

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

The right type or grade of lubricant is as important as having lubricant in the bearing in the first place. “Even the very best bearing can only show optimum performance if it is lubricated correctly,” Jan says. “It’s extremely important to choose the right bearing lubricant and to apply it at the most suitable interval and in a specific way. Our engineers consider grease and oil to be a fundamental component of the bearing arrangement and therefore as important as the bearing, housing and sealing itself.” The ROI (return on investment) of these systems is quick, not only because it ensures fewer shutdowns due to unexpected failures causing production losses, but also because there is a huge saving in lubricant cost. “In our experience, automatic lubrication reduces bearing failures by more than 36% bringing about a significant saving in repair and spare part costs,” Jan says in conclusion. “In many instances we can bring about savings of up to 70% just in lubricant costs alone due to the accurate timing and dosing of lubricants.” Jan Backer, SKF South Africa, Tel: (011) 821-3535, Email: jan.backer@skf.com

Nov/Dec 2011


BEARINGS & LUBRICATION

Smearing the Hard Stuff

A cutting fluid is a type of coolant and lubricant designed specifically for metalworking and machining processes. There are various kinds of cutting fluids which include oils, oilwater emulsions, pastes, gels, aerosols and air or other gases. They’re made from petroleum distillates, animal fats, plant oils, water, air and other raw materials.

T

he properties sought after in a good cutting fluid are the ability to keep the workpiece at a stable temperature and to maximise the life of the cutting tip by lubricating the working edge, in order to prevent rust on machine parts and cutters. Most importantly the fluid should be safe for people to handle and good for the environment in terms of toxicity, bacteria and fungi.

Maximise the life of the cutting tip by lubricating the working edge, in order to prevent rust on machine parts and cutters Lubricants and coolants

Spectra Lubricants is a Port Elizabeth based company specialising in an extensive range of lubricants, coolants, corrosion protection fluids and cleaners for the metal working industry. “SA Mechanical Engineer” talks to Levin Slabbert, account manager at Spectra to get to grips with the ins and outs of this market. “Local industry still tends to buy on price when it comes to lubricating coolants which is counterproductive. We often see clients who invest in a CNC machine worth millions and then they use the cheapest products available to protect it.”

Across the globe

Spectra is the sole distributor in Southern African for the full range of products from Cimcool in The Netherlands. Koen Eeckhout, regional distribution manager of Cimcool in the Netherlands says, “Today the Cimcool’s European headquarters is still situated on the site in Vlaardingen where it all started. From here, we develop and produce our range of industrial fluids which are distributed across the globe.” Just minutes into the chat with Koen we realise that choosing a machining fluid is not as simple as just picking one off the shelf. Rather, it’s a scientific process which is probably why users and even manufacturers are often confused. “Apart from not cooling the workpiece properly, resulting in an inferior product, clients are shortening the life of highly expensive tools. Clients have to change fluids frequently and most important, they have to understand that fluids could very well be harmful to the operator and the environment,” he explains.

(Left) Koen Eeckhout, regional distribution manager of Cimcool in The Netherlands and Levin Slabbert, account manager at Spectra Lubricants

“Our approach is scientific, starting with an audit of the company and the products they manufacture so that we can evaluate the specific requirements suitable to their processes in order to select the right product for each application,” he adds. “For example, a part may be prone to rust because it’s shipped directly after manufacture.”

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011

35


BEARINGS & LUBRICATION

A bit like having your mother-in-law around, there’s a lot of yakking, but nobody’s really listening to any of it Corrosion

Instead of having to go through the extra process of applying corrosion protection, we have a special fluid with dewatering characteristics which protects the part when it comes out of machining. Also, at the other end, the part may need to go direct into assembly. The end-user may not want to first clean off thick layers of grease,” elaborates Koen. “We have a fluid, for example, for machining crankshafts, which is fitted at the engine factory directly from the packaging into the engine without the need to wash it. “Our fluid contains corrosion protection compatible with the engine in question thus eliminating the need to wash it beforehand as is usually the case. But even so, we produce special cleaning fluids if requirements aren’t as stringent and specific as this.”

Huge benefits

each to the benefit of the machine shop. “Generally the problem with coolants is that it’s a bit like having your mother-in-law around, there’s a lot of yakking, but nobody’s really listening to any of it,” says Koen with a smile. “Our products come at a premium, but in return the users reap the gains achieved due to fluids lasting longer, machines tools lasting longer, parts produced being more accurate and because far less fluid is used with our products.” To prove their point in terms of promising the manufacturer a saving after a scientific analysis, Cimcool is launching a scheme in South Africa whereby the user will not have to pay for the products recommended by Cimcool if no discernible saving is achieved, Koen explains. “In addition to training customer’s machine operators in terms of fluids, we have a maintenance plan offering where we form a partnership with the client for product and process optimisation. This is a concept whereby the purchasing of all chemicals, metalworking fluids, recycling units and waste treatment/disposal is our complete responsibility.” Levin Slabbert, Spectra Lubricants, Tel: (041) 403-1500, Email: levins@spectralubricants-sa.co.za

There are many products like these,

36

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011


Market Forum Diesel-powered emergency ventilation fans Many mining companies are introducing emergency dieselpowered ventilation for their underground operations to enable the safe evacuation of mineworkers in the event of unscheduled power cuts. Actom Mechanical Equipment, a leading designer, manufacturer and supplier of axial flow and centrifugal ventilation fans for underground mines, has manufactured and installed a batch of dieseldriven ventilation fans in some of the underground mines of leading platinum mining houses for emergency evacuation when power cuts occur.

Shaft and Thembelani Shaft and at its Union mine’s Spud Shaft and 12A Shaft. “In all these installations the emergency fans are T-ed into the existing ventilation system so that they can be quickly deployed to supply the essential ventilation needed in the underground roadways in the mine used for evacuation when a power outage occurs,” commented Kobus Cilliers, Actom Mechanical Equipment’s project manager responsible for the contracts.

At Khuseleka Shaft a crane had to be used to lift the existing vertical ventilation outlet diffuser located at the top of Since 2009 the comthe shaft to enable pany has executed installation of the contracts of this kind emergency fan. “In for major platinum this case the existing mining groups Imelectrically-powered pala Platinum, An- A view of the emergency fan installation at Anglo Platinum’s Thembelani Shaft fan is located at the glo Platinum and bottom of the shaft Lonmin. The first because of the need to suppress the noise that would othwas for the design, manufacture, supply and installation erwise disturb a nearby community settlement, therefore of two direct coupling 1,4 m diameter centrifugal fans necessitating use of the discharge diffuser at the head of powered by Volvo 6 diesel motors at Impala Platinum’s the shaft,” Kobus explains. No. 17 shaft. This was followed by a contract for four belt-driven 2,2 m diameter axial flow fans powered by Craig Johnston, Actom Mechanical Equipment, Tel: (011) 871V6 Deutz diesel motors at Anglo Platinum’s Khuseleka 6789, Email craig.johnston@actom.co.za

Lubricant pack for mini-bulk one way solution

Engen Lubricants has launched a brand new packaging concept for its lubricating oils and greases. Engen IPS (Innovative Packaging System), a first of its kind in Africa, consists of a five-layer plastic bag housed on a wooden pallet and holds 900L of oil or 850kg of grease. The unique construction of the bag prolongs product life when exposed to outside storage in the harsh African sun. The Engen IPS outlet valve is a standard 2-inch Camlock coupling for oils and 3-inch for greases. Clingage is reduced to below 0.3%, compared to ±1% when using steel drums. The reduced clingage is due to the unique bag stretching device that comes with the Engen IPS system. Various lubricant products are available in the Engen IPS pack including engine, hydraulic and gear oils, as well as greases. Engen IPS can either be used in a fixed position (e.g. workshop) or in a mobile environment (e.g. on the back of a small truck for top-up jobs). It requires no EIA for installation and supplies product on tap. Units can also be stored 2 high. The IPS concept further offers enhanced dispensing solutions and containerised mobile lubricants store and bund facilities. Due to the filling technology used, the product is protected against all external contamination possibilities and is also emptied under a closed system to further enhance cleanliness practices. The system is not rented and as such is a one-way logistics solution for African countries and rural areas. It is also lighter by more than 70% when compared with other mini-bulk containers - 20 units fit a standard 20”ft shipping container, giving more than 7% extra volume transport benefit. The Engen IPS system is environmentally friendly and each component can be fully recycled. The unit is ideal for filling with used oil prior to disposal through approved used oil authorities. Contact: Customer Service Centre: 08600 36436 | Email: 1call@engenoil.com | Website: www.engenoil.com

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011

37


Market Forum New dry gland expeller

The first installation of a Hi-Seal dry gland expeller by Weir Minerals Africa in South Africa, at Muhanga Mining’s coal mine in Mpumalanga, has significantly outperformed existing alternatives by several months.

has really proved itself to show significant sealing improvements in the market. The Hi-Seal features a larger diameter expeller with a unique patented expelling vane design that generates a significantly increased pressure in the expeller ring chamber at the same pump speed achieved by conventional sealing arrangements. In addition to an incomparable sealing performance, the benefits of this modification include extended component wear life, reduced power consumption and operational costs, as well as lower maintenance costs. The replacement of the shaft sleeve need only take place if necessary, which is usually when the Hi-Seal is changed out, because the wear traditionally created by leaking glands is eliminated. Weir Minerals Africa Ltd, Rene Calitz, Tel: (011) 929-2622, www. weirminerals.com

An illustration of a Warman 6/4E AH pump fitted with a Hi-Seal expeller sealing arrangement

Simone du Toit, sales engineer at Weir Minerals Africa, says the first Hi-Seal, developed for sealing at high inlet pressures, was installed on pumps at the mine in July 2010 and delivered a premium shaft sealing performance, with no leakages reported until May 2011.

Contact Louise Taylor on Tel: (011) 781-1401, Fax: (011) 781-1403, Cell: 082 898 3073 or Email: editorial@promech.co.za to book your advertising space

“What made the initial installation so special is that we fitted a 6/4E Hi-Seal on a Warman 6/6EG gravel pump and it maintained the seal for the entire ten months,” Simone says. “Glands in this specific application generally start to leak after two to three weeks of application, so the Hi-Seal

ROMECH PUB p - T, O, G 2/20/11 9:54 PM Page 2

omposite

C

38

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

M

Y

CM

MY

CY CMY

Nov/Dec 2011

K


Market Forum Mufflers and filters from USA

Artic Driers International have been appointed as a distributor for the silencers and mufflers produced by the Allied Witan Company of Cleveland, Ohio, USA. Allied Witan Company has specialised in noise suppression of compressed air exhaust associated with air-operated equipment for over 60 years. With the Atomuffler and Bantam brand product lines, Allied Witan Company is an international market leader in the area of compressed air noise suppression. The entire Allied Witan Company product offering of mufflers and filters provide quieting and filtering solutions for a wide range of pneumatic applications, from simple pneumatic applications to large desiccant air dryers, along with air intakes and exhausts for compressors and blowers to name just a few of the applications.

Glass making made more cost-effective

Eirich mixing technology plays an invisible role in our daily lives with its advanced homogenising functions. Over recent years, glass makers have relied more and more on this technology to produce large scale, A-grade glass products used in various everyday functions; such as watching television, generating light, preserving fruit by bottling, and many more.

With its high profile in the air treatment industry, Artic Driers is well positioned to support this proven product on a broad front, says Allen Cockfield, CEO. of Artic. “Due to our position in the air treatment industry Artic has also created an opportunity to access the pneumatics industry,” states Allen. The Allied Witan Company product range offers proven solutions to noise pollution problems, and Artic will stock a broad range of the popular mufflers and filters in it’s 600 m² warehouse in Gauteng Johannesburg to support this product along with other its other well-known international brands. Allen Cockfield, Tel: (011) 425-3484, Fax: (011) 425-3462, Email: allen@articdriers.co.za

tial,” says Louis Eksteen, business development manager, Birkenmayer. “This improves the specific melting rates of glass without compromising on final product quality during tempering.”

Whether manufacturing hollow, flat, optical or special glass products, Eirich mixers, distributed in South Africa by material processing experts Birkenmayer, have proven to optimise production costs by lowering energy requirements for mixing and smelting; reducing wear of refractory material and the amount of raw materials needed; optimising costs associated with maintenance; and, in line with global environmental concerns, reducing CO2 emissions. Eirich mixers also drastically shorten mixing times, helping factories improve throughput while maintaining the highest possible product quality.

Eirich technologies are adaptable to various glass manufacturing processes, but the objective remains for all ingredients, including minor and macro-ingredients of various ratios, to exit the mixer as a homogenous mix. “For glass manufacturing purposes, the industry standard variation coefficient is around 10%, but with Eirich intensive mixers, batches measure an impressive variation coefficient of less than 5%,” says Louis. “As it is not uncommon for Eirich intensive mixers to operate in glass making factories for over 40 years, this high level of performance has been repeatedly proven. Low installation costs further make Eirich mixers the ideal solution to cost-effectively manufacture various kinds of glass,” concludes Louis.

Louis Eksteen, Business Development Manager, Tel: (011) 970-3880/8, Email: louis@ “In the glass making process, These raw ingredients are turned into A-grade glass products with the birkenmayer.co.za, Website: true homogeneity is essen- help of Eirich’s advanced mixing technologies www.birkenmayer.co.za

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011

39


40

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011


Market Forum Large-ported units to the market with the MU series Tectra Automation, local distributors of drive and control technologies from Bosch Rexroth and a subsidiary of the Hytec Group, presents the robust MU Series filter, regulator and lubricator (FRL).

The MU Series is available with accessories including bowls, protective guards and mounting brackets. Erika Bennion, Tectra Automation, Tel: (011) 971-9400, Fax: (011) 971-9440

Erika Bennion, Pneumatics Product Manager, Tectra Automation, explains, “In addition to our mainstream service units that are used in various industries, we now offer the larger ported MU range of air preparation units. These units are more flexible – in terms of having up to two-inch units available – and their die-cast aluminium bodies make them more suitable for mining and foundry environments.” “Our focus has always been on the smaller FRL units, but in response to regular requests for big-ported service units, we decided to expand our current FRL range to include the MU series,” explains Bennion. The MU Series ranges in size from a half-inch to two inches, whereas the mainstream FRL units range in size between a quarter-inch and an inch.

Management Contract

Johnson Controls Global WorkPlace Solutions (GWS), a leading provider of facilities, commercial real estate and energy management for many of the world’s largest companies, today announced it has been awarded a facilities management contract for Shell Oman Marketing Company’s retail and commercial sites in the Sultanate of Oman. The agreement covers nearly 400 sites that sell fuels and lubricants to consumers and businesses in the country. In March 2011, Johnson Controls GWS announced its partnership with Shell to manage and maintain 12 000 Shell retail sites in 27 countries. Oman is an additional country to that agreement, with Johnson Controls GWS delivering services from October 4, 2011.

The Bosch Rexroth MU Series FRL unit available locally from Tectra Automation, ranges in size from a half-inch to two inches

Shell Oman network delivery manager, Hafidh Al Azkawi says, “We look forward to the global experience of Johnson Controls delivered with an Omani touch at a local level. The contract will no doubt benefit our customers who can now look forward to well-maintained sites which offer greater convenience and safety for them. This will help us achieve our retail vision, which is to be the best in the industry.” Julie Kimble, Johnson Controls Global account leader for the Shell retail business, says, The Johnson Controls team on the Shell account are all looking forward to delivering our services to Shell retail and commercial sites in Oman, as we have done across the world. As facilities management is our core business, we will provide improvements in health and safety, security and environment, and operational excellence to help Shell deliver the best possible customer experience in the country.” John Davies, Johnson Controls Global WorkPlace Solutions, Tel: +44 (0) 1252-346409, Email: john.p.davies@ jci.com

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011

41


Market Forum Mill classification cyclones

Multotec has secured the order to supply a 12-way mill classification cyclone cluster to the Ngezi Phase 2 project, situated some 150 km south west of Harare, in the North Chamber of the Zimbabwe Great Dyke. The order placed by DRA Mineral Projects follows Multotec’s successful provision of a similar cluster for Phase 1 of this project in 2009. The Multotec classification cyclone cluster comprises 12 high capacity 420 mm diameter cyclones. These high capacity cyclones will be supplied with 25 mm replaceable natural rubber liners and mild steel shells. The replaceable rubber liners deliver up to three times the life of conventional liners which reduces operating costs, maintenance and stockholdings. The cyclones will be installed in closed circuit with a ball mill, with overflow reporting to flotation and underflow reporting back to the mill circuit for further grinding. Nine of the 12 cyclones will be in operation, with the remaining three on standby to ensure continuous operating time. The cyclones have pneumatic valves for automation and to make the process less labour intensive. The feed pulp distributor and the underflow tank are ceramic tiled with a rubber lined overflow tank.

eCAD tools with a 3D dimension

RS Components announces the release of their NEW PCB Converter for SketchUp tool, which allows designers to import Intermediate Data Format (IDF) files into Google SketchUp. The new module adds a 3D CAD back-end capability to PCB design tools and takes SketchUp into the electronic product design domain, transferring files from any CAD environment providing IDF output into COLLADA format. Google SketchUp is already known as the world’s most popular free 3D design tool, and is rapidly gaining a widespread and loyal following with electronics design engineers. This is not only due to its capabilities as a CAD package, but also due to the fact that many of these capabilities are available in the free version. Using PCB Converter for SketchUp, users can, for the first time, import IDF files, a file specification designed specifically for the exchange of printed circuit assembly data between mechanical design and PCB layout. PCB Converter for SketchUp is available free of charge without limitation to all members of DesignSpark, the RS online electronics design community and resource centre. DesignSpark provides free access to information, resources and reviews. Users will also have access to a full suite of video tutorials and examples. PCB Converter for SketchUp can be downloaded for FREE from the DesignSpark SparkStore at www.designspark.com, from the RS website at www.rsonline.co.za/electronics, or from the plug-ins area on the Google SketchUp website, http://sketchup.google.com/. Contact: Devon Ross, RS Components SA, Tel: (011) 691-9300, Email: editorial.za@rs-components.com, Website: www.rsonline.co.za

Pump slurries

A range of disc pumps designed for the pumping of shear sensitive solids and gaseous froths, as well as for efficient handling of aggressive slurries with heavy viscosities and highly abrasive solids content has been launched by Wegezi Power Holdings part of BMG (Bearing Man Group).

A radial cluster of cyclones for de-slimming applications

“This is standard equipment which will allow us to supply spare parts at relatively short notice,” Tumi Matsebedi, a senior process engineer at Multotec, says. “The client has also been advised of strategic and two-year operating spares to allow for future maintenance planning. However, the cyclone cluster for Phase 2 differs from that supplied for Phase 1 in that it will be equipped with a specialised gantry to allow access to the valves for ease of maintenance. “This equipment will be transported by road from South Africa to Zimbabwe, and during the design stage particular attention was paid to ensuring a compact design that won’t require a low bed or abnormal load vehicle. This will help keep logistical costs down.” Bernadette Wilson, Multotec Group, Tel: (011) 923-6193, Website: www.multotec.com

42

THE SOUTH AFRICAN MECHANICAL ENGINEER

“Durable Discflo pumps, which have been developed to solve problems in pumping applications, reduce maintenance costs, minimise lost production time and combat unacceptable product degradation,” says Stewart Lombard of Wegezi Power Holdings. “These new clog free disc pumps are perfect for applications where abrasion, high viscosity, entrained air, excessive wear and corrosion problems affect pumps and degrade products. “The Discflo pump, with disc technology that encompasses the principles of boundary layer adhesion and viscous drag, is neither a centrifugal pump nor a positive displacement pump, but it does the work of both. These pumps provide a powerful dynamic force that moves the product through the pump in a smooth, laminar flow.” Released by Lindy Morton, Festivitas, Telephone (031) 502 2374 or 083 268 6666 Telephone:+27(0)12 386 1395/1 or +27(0) 79 709 9862 / 9832 Fax :+27(0)12 386 1397 Email:pumps@wegezi.co.za Web :www.wegezi.co.za

VOL 61

Nov/Dec 2011


Market Forum Green technologies

Green technologies in the heating, ventilation and air conditioning industry have come to the forefront of discussions regarding sustainable development and construction practices.

with stored thermal energy during off-peak hours between 21h00 and 06h00 and depleted during operating hours in conjunction with the chillers. Chilled water is reticulated through a closed loop piping system to in-ceiling FCU’s, which provide cooling to the occupied areas. The FCU’s are installed according to the thermal zoning of the building, and each fan coil is fitted with a controller that varies the amount of cooling based on the room temperature. Each FCU is also integrated with motion sensors to allow economy mode operation in un-occupied areas. During economy mode, the temperature is allowed to float between a wider range around the set-point temperature; this results in reduced energy consumption when areas are not in use. Once an area becomes occupied, normal operation continues to the design specification. Heating is achieved by the reverse cycle heat pump capability of the chillers, with the hot water being reticulated through a dedicated closed loop piping system to the inceiling FCU’s. This system decreases electrical demand of the building by a third when compared to electrical resistance heating Menlyn Maine, Tel: (012) 361-7758, www.menlynmaine.co.za

“Workplace” compressed air systems

The Workplace GA Series from Atlas Copco, global leader in compressors and air purification equipment engineering and technology, is an ‘All-in-One’ compact, stationary compressed air system that can be conveniently placed anywhere on the factory floor to meet clean air requirements wherever it is needed. Three images of the tanks installed in the Nedbank building at Menlyn Maine

Menlyn Maine is implementing leading international green technology from Europe in Africa’s first green city precinct in heating, ventilation and air conditioning (HVAC) systems.

“A combination of distinguishing features and benefits, including extremely low noise levels, allow ‘Workplace’ GA compressed air system to operate conveniently and cost effectively at point-of-use, making a conventional

These systems reduce the connected load of the HVAC systems to approximately half that of standard chilled water systems while also providing demand side management strategies such as load shifting, thereby reducing the impact during peak demand hours to the electrical supply. The upgrade to four-pipe Thermal Storage allows the elimination of electric resistance heating, further reducing the power consumption required during winter months. Heating and cooling is provided by means of a 4 Pipe Thermal Energy Storage system, using air cooled reversible heat-pump chillers, Christopia thermal storage system and four-pipe in-ceiling fan coil units (FCU’s). The chillers are sized to provide for approximately 50 percent of the peak building cooling load, while the thermal storage tanks provide for the remaining 50 percent of the peak load. The tanks are charged by the chillers

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011

43


Market Forum compressor room obsolete,” explains Philip Herselman, Atlas Copco Business Line Manager, Industrial Air Division. Constantly finding ways to reduce electricity consumption is no longer a ‘must-be-seen-to-be-doing-something’”, says Philip. “It has become a critical part of a company’s drive to keep overheads down and profitability up. Our GA VSD (Variable Speed Drive) compressor, which complements the ‘Workplace’ All-in-One compressed air system, reduces air leakage by operating at lower working pressure and perfectly matches capacity to air demand. These are features that deliver energy savings of up to 35% and not only reduce costs but contribute to shrinking the carbon footprint of a company”. The compressor features Elektronikon control, an advanced

control, monitoring and communication system, which further maximises overall compressor efficiency and reliability, minimising maintenance costs. All worldwide interfaces for remote control and communication are available. Standard options on the ‘Workplace’ GA Series includes an integrated dryer, combating moisture, dirt particles and aerosols in plant air that can cause contamination of products and damage to pneumatic equipment. Atlas Copco’s development of compatible equipment enhances the quality and reliability of the “Workplace” system, benefiting a broad spectrum of applications. Philip Herselman, Industrial Air Division, Tel: (011) 821-9110, Email: phillip.herselman@za.atlascopco.com , Website: www.atlascopco.com

Watershed year

Jet Park-based Killarney Engineering, a subsidiary of Andrew Mentis, is experiencing a watershed year, with a significantly increased order book that includes large orders for its unique serrated grating. Newly-appointed general manager, Prega Sundran, says the unprecedented upturn in the company’s business can be attributed to repeat orders from loyal longstanding clients, coupled with an influx of large orders from first-time customers. “For more than 12 years, this business has been built on the twin pillars of service and quality,” he says. “We are a small, but highly productive company and we treat customer companies of all sizes with equal attention and commitment. Customers welcome our ability to tailor-make products to suit their own unique requirements, at highly competitive prices and with fast turnaround times. We are able to offer this price advantage because we source all our raw materials from our parent company, Andrew Mentis, which purchases these materials for its own product range in bulk quantities.”

44

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011


Market Forum between RSD and US-based CSI. The vehicle is a unique two-seater landmine detection unit that is blast-survivable, overpass-capable and field-reparable. This exceptional vehicle is a derivative of the single occupant Husky that has been combat proven in conflict situations around the world since the early 1980’s. The Husky two-seater variant allows for a second person to be placed in the vehicle. This two-seater VMMD responds to the warfighter’s immediate need to mitigate the risks of task overload on a single Husky operator, increases the Route Clearance Package’s (RCP) ability to find and neutralise improvised explosive devices, or IEDs, and provides direct fire capability for the lead vehicle of the RCP.

From left to right – Prega Sundran, general manager and Andrew Mentis junior managing director of Killarney Engineering during quality inspection

Killarney Engineering was established on the East Rand as a small grating company that also produced positive die-line safety walkway products. Andrew Mentis purchased the company in 1999 and moved the operation to its current site in Webb Street, Jet Park. Elaine Van Rooyen, Andrew Mentis, Tel: (011) 255-3200, www.mentis. co.za

The vehicle’s kit allows for the platform to be transported with air assets in a roll-on/roll-off configuration, increasing the readiness level and, at the same time, decreasing the logistical footprint and costs of maintaining the equipment in the theatre of operations. The Prototype Integration Facility (PIF) of the US Army Aviation and Missile Research, Development and Engineering Center (AMRDEC) has integrated ground-penetrating radar, a remote weapon station and various other devices onto this innovative multi-purpose sensor platform, considered to be the safest in the world. Carl Rehder, RSD (A Division of DCD-Dorbyl, Tel: (011) 914-1400, Fax: (011) 914-3885

SA’s Husky 2G vehicle honoured

Hailed by the United States Army as “demonstrating significant impact to army capabilities, potential benefits outside the army and inventiveness”, the South African-made Husky 2G VMMD (Vehicle Mounted Mine Detector) has received one of the highest accolades in the military world — being numbered among the US Army’s top ten “Greatest Inventions”. The Husky 2G is designed and manufactured in South Africa by RSD and marketed internationally through a partnership

The Husky 2G is designed and manufactured in South Africa by RSD

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011

45


Market Forum Subscription

LED inspection

Micro-Epsilon offers the new colour Control MFA-5 for the inspection of LEDs starting at a basic version that offers five measuring channels. This simplifies the inspection of LEDs for their function, contrast and luminosity. The new MFA-5 is extremely compact and can verify up to five LEDs simultaneously. The measuring system can be extended in a modular fashion by adding extra MFA-E modules in batches of 5 channels.

Please fax us if you wish to subscribe to â&#x20AC;&#x153;SA Mechanical Engineerâ&#x20AC;? at R400,00 (incl postage and VAT) per year; R945,00 per year for Africa/Overseas. We will post you an invoice on receipt of your fax.

PROMECH PUBLISHING

Fax No: (011) 781-1403

From:...................................................................................... (insert your name) Title: ...................................................................................... Company: .............................................................................. Address: ............................................................................... ............................................................................................... ...................................................................Code: .................. Telephone: ( Fax: (

The light from the target object is transmitted to the inspection system via a flexible, 2mm diameter, plastic optical fibre and is therefore evaluated dynamically using a colour sensor for colour and intensity. The colour value, which is evaluated within just a few milliseconds, is output as RGB-, HIS or CIE values and then transmitted via USB or RS232 interface at a rate of between 9,600 and 115,200 Baud to a higher level inspection or evaluation system for further processing. In order to ensure a wide measurement range for intensity (illumination) the sensitivity of the sensor can be adjusted by using two different modes (High Sensitivity Mode and Low Sensitivity Mode). Due to the levels it is possible to recognise LED colours up to +/- 4 nm. The installation of the system colour Control MFA-5 is performed via a test-software, that is included in the scope of delivery. The recognition results are displayed in detail. Elton Murison, TeL: (012) 809-9500, Email: e.murison@esteq.com

Engineer Placements Professional opportunities

Our job board continues to display a wide variety of excellent job positions that you can review and apply for on- line. Keep your credentials on our secure and confidential database, update them at any time. We keep in touch with you.

www.engineerplacements.com

46

THE SOUTH AFRICAN MECHANICAL ENGINEER

) ....................................................................

) ................................................................................

Email:.....................................................................................

Index to Advertisers AMS 14 Airconduct 36 Artic Dryers 22 Association of Arbitrators 32 Atlas Copco 28 AST Pyroshield Inside Front Cover Bearings International 13 Chem Systems 16 Derma Plastics 40 Donkin 8 Energy Cybernetics 26 Engen 30 Engineer Placements 46 Esteq 20 Europair Inside Back Cover GEA Outside Back Cover Horne SA 38 John Thompon Outside Front Cover Maizey 31 Mecad 44 Mining Indaba 4 Zest 18 VOL 61

Nov/Dec 2011


THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011

47


Competence in Heat Transfer Suppliers of a wide range of heat exchangers GEA Ecoflex

Cut the cost of corrosion!

Need high resistance to pitting and crevice corrosion â&#x20AC;&#x201C; but not the expense of titanium? SWEP's Mosteel line may be the answer. Also excellent resistance to chloride stress corrosion cracking. And our state-of-the-art brazing technology eliminates the risk of intergranular corrosion. Mo-steel heat exchangers cut worries and costs in pulp and paper industries using corrosive, chloride-rich fluids. The pit resistance of SWEP's Mo-steel CBEs can be a significant economic factor in oil coolers in various industries (sugar, plastics etc). Even a corrosive, polluted water supply can be used in our Mo-steel exchangers.

GEA Refrigeration Technologies

GEA Grasso (Africa) (Pty) Ltd

19 Chain Avenue, Montague Gardens, 7441, PO Box 36815, Chempet, 7442, South Africa Tel. + 27 21 551 4034, Fax + 27 21 551 4035

48

THE SOUTH AFRICAN MECHANICAL ENGINEER

VOL 61

Nov/Dec 2011

www.grasso.co.za

SA Mechanical Engineer  

The SA Mechanical Engineer" is the official magazine of the SA Institution of Mechanical Engineering, It is also endorsed by the following b...