www.howden.com
THE HOWDEN THOMASSEN FFP™ OIL-FREE AND VIRTUALLY FRICTION-FREE: THE PISTON THAT FLOWS ON A FILM OF PROCESS GAS
A SINGLE CONCEPT WITH MULTIPLE BENEFITS PRACTICALLY ELIMINATES RIDER RING WEAR. INCREASES THE LIFETIME OF PISTON RINGS AND STUFFING BOX ELEMENTS BY KEEPING THE PISTON CENTRED IN CYLINDER. REMOVES THE NEED FOR LUBRICATION, THUS REDUCING COSTS AND PREVENTING CONTAMINATION. REDUCES TIME AND COSTS INVOLVED IN PREVENTATIVE MAINTENANCE. REDUCES PRODUCTION LOSSES. ENHANCES RELIABILITY AND AVAILABILITY. FFECTIVELY REMOVED THE NEED FOR E A SPARE STANDBY COMPRESSOR. COPES WITH ALL TYPES OF PROCESS GASES. CAN BE RETROFITTED TO EXISTING COMPRESSORS. OFFERS A FAIL-SAFE DESIGN THAT REMOVES RISK. REDUCES POWER CONSUMPTION. REDUCES NOISE LEVELS.
THE HOWDEN THOMASSEN FREE FLOATING PISTON HOWDEN IS AN ACKNOWLEDGED GLOBAL LEADER IN AIR AND GAS HANDLING TECHNOLOGY, WITH LOCAL BASES IN 17 COUNTRIES ACROSS EVERY CONTINENT AND A REPUTATION FOR INNOVATION THAT PUSHED THE BOUNDARIES OF RELIABILITY AND EFFICIENCY. A PASSION FOR COMPRESSION Our products underpin many of the world’s most critical industries including power generation, petrochemicals and manufacturing, and include a comprehensive range of reciprocating process compressors for industries like oil, gas, chemicals and refining. The Free Floating Piston is a unique development in compressor technology that uses a cushion of pressurised process gas to float the piston, virtually removing rider ring wear at a stroke. In the traditional choice between lubricated and non-lubricated systems, the solution to one problem often become the cause of another:
Lubricated cylinders
Non-lubricated cylinders
Oil consumption.
No oil consumption.
Tendency for valve plates to stick.
No sticking, longer valve life.
Lubricant volume is adjusted to maximise compressor capacity, which means that oil concentration in the process gas increases at part load conditions.
No lubricant.
To prevent contamination of the process gas, oil must be separated and drained.
No draining of oil required.
To prevent contamination of equipment, coolers must be cleaned regularly.
No oil contamination.
Drained oil must be transported and disposed of, with environmental consequences.
No oil to dispose of.
Cylinder lubrication system requires regular maintenance.
No cylinder lubrication system to maintain.
HOW IT WORKS
VIRTUALLY FRICTION-FREE SUPPORT ^ As it travels in the cylinder, the FFP™ is carried by a thin cushion of process gas. While the concept is simple, the implementation demands the highest standards of precision engineering.
ACCURATELY DIRECTED GAS FLOW ^ Pressure-sensitive valves have been added to the face of the piston. During the compression stroke, these valves are pushed open to allow the interior of the piston to flood with process gas under high pressure. The gas is then forced out through flow nozzles integrated into the bottom of the rider rings to form a film of pressurised gas, around 10–50 microns deep, that supports the weight of the piston.
FAIL-SAFE OPERATION ^ The lower surface of the rider rings carry
a machined profile that ensures the gas is distributed accurately to create a bearing layer, and the rider rings have been relocated to sit between the piston rings, which thus form a sealed enclosure. Contact between the rider ring and the cylinder lining is effectively reduced to zero, and as long as there is pressure in the system the cushion layer is maintained, providing a fail-safe mechanism in the event of problems arising elsewhere. Special designed non return valves
flow nozzles
A RADICAL RESPONSE TO THE DEMANDS OF MODERN INDUSTRY As process requirements become ever more critical and environmental constraints more stringent, oil-free compressor cylinders are becoming increasingly prevalent. Without lubrication, however, conditions within the cylinder can accelerate the wear so drastically that running time between maintenance stops may be reduced to a few hundred hours. At the same time, commercial pressures increasingly demand uninterrupted running of three years or more.
The FFP™ brings all the advantages of oil-free operation without the usual drawbacks, while avoiding the expensive and time-consuming complications introduced by of lubrication systems. It already has more than ten years proven performance in some of the most demanding industrial situations.
Our engineers undertook a radical rethink of the fundamental principles of compressor design, investigating the principles and possibilities of each component. The outcome, the FFP™ is an elegant and ingenious method of virtually eliminating rider ring wear. It uses pressurised process gas to provide a cushion that lifts the piston clear of the cylinder lining, so that the rider ring is only in contact with the cylinder during the brief start up and shut down periods. The volume of gas required is extremely small – less than one per cent of the cylinder capacity – and compensated for in the cylinder design, so there is no loss of overall capacity.
RESULTS THAT QUICKLY REPAY INVESTMENT After successfully completing a rigorous series of in-house static and dynamic prototype testing, we worked in partnership with a customer to pilot the system on-site in a heavy duty hydrogen compressor. This first installation has now been running without problems, with only minimal breaks for planned maintenance, since 1998. Almost 250 FFP™ systems have been installed to date, and the data accumulated over ten years of industrial experience shows that rider ring wear is reduced to practically zero, repairs are minimal and reliability is excellent.
ELIMINATE RIDER RING WEAR PROBLEMS, AND THE WEAKEST POINT BECOMES ONE OF THE STRONGEST.
www.howden.com
PASSION FOR COMPRESSION Howden Thomassen Compressors BV is a leading international supplier of innovative, high-quality compression equipment to the world’s most vital process industries. Since 2011, it has been part of the global Howden organisation, the world’s leading supplier of fans, compressors, blowers and rotary regenerative heat exchangers. Recognised and respected for leading edge design and the highest standards of engineering, Howden has companies based in 17 countries, combining a local level of service with access to world-class expertise and unrivalled experience. Everything we manufacture is backed by a lifetime commitment to spares, aftermarket services and advice on upgrades and retrofits.
If you would like to know more about the Free Floating Piston, or investigate the cost benefits it might bring to your own installation, please contact:
Howden Thomassen Compressors Havelandseweg 8-a PO BOX 99 6990 AB Rheden The Netherlands Tel: + 31 (0) 26 4975200 Fax: + 31 (0) 26 4975201 Web: www.thomassen.com
Howden Thomassen Compressors BV is a member of the Howden Group of companies.
©Howden Group Limited. All rights reserved. 2012 Howden and the flying H logo are registered trade marks belonging to Howden Group Limited.