Page 1


UNIQUE FEATURE OF WRS KOTA


BRIEF INTRODUCTION Used for transportation of Liquefied Petroleum Gas. Ist 4-Wheeler Wagon was designed in 1972. 8-Wheeler Wagon was introduced in 1992 on increasing freight demand.


MAIN FEATURES OF LPG/WAGON  LPG is a mixture of liquefied Propane & Butane Gases.  Remains at 15.85 Kg/Cm2 & ambient temperature 550C (1300F) in Barrel.  Highly inflammable substance.  Comes under Classification of dangerous goods.  Needs high level of safety & special care in service.  POH/ROH should be carried out in a workshop fully equipped for the purpose.


UNIQUE FEATURE OF WRS KOTA  The Only nominated workshop for POH of BTPGLN/BTPGL Wagon on Indian Railways.  This involves -thickness testing followed by high pressure testing of valve gear as per RDSO’s instructions. Compliance in high safety of man & material. Measures suggested by Boiler & Factory Inspector of the state and Dept. of explosiveNagpur.  Equipped with high sensitive equipments -like explosive meter, oxy meter to ensure LEL (Lower Explosive Limit) of LPG in degasified wagons in order to ensure full safety.


UNIQUE FEATURE OF WRS KOTA  POH of LPG Wagon was started in Kota Workshop in the year 1981.  Previously, All type 8-wheeler i.e. BTPGLN & BTPGLC were attended only in Kota Shop.  At Present all type 8-wheeler & 4-wheeler LPG wagons are attended only in KTTW since Oct-07.  Owner of 8-wheeler & 4-wheeler wagonsIOC/BPCL/HPCL.

 Ever highest Outturn by ShopFebruary-08

119 VUs

 IInd Ever highest Outturn by ShopFebruary-05

117 VUs


POH FLOW PROCESS FOR LPG INSPECTION & REPAIR Ensure De-gassing Certificate ↓

Check for Gas (LEL by Explosive & Oxy meter) ↓

Check Deficiencies of Components ↓

Test Barrel Thickness ↓

Fill 2000 ltrs water ↓

Removal of Eduction & Safety Valves ↓

Keep Open to Air for 24 hrs


POH FLOW PROCESS FOR LPG INSPECTION & REPAIR Circulate Air ↓

Recheck For gas (LEL by Explosive & Oxy meter) ↓

Open & Remove Diaphragm ↓

Scrapping/Cleaning of Piping Arrangement & Diaphragm ↓

Change Gasket & Fit Diaphragm ↓

Fitment of Repaired Eduction Valves


POH FLOW PROCESS FOR LPG INSPECTION & REPAIR Fill water Completely in Barrel ↓

Hydraulic Test (21.65 Kg/Cm 2) ↓

Fitting of Safety Valve ↓

Drain Water & Re-circulate for next Wagon/Storage Tank ↓

Re-test Wagon by Pn. Pressure


ROH FLOW PROCESS FOR LPG INSPECTION & REPAIR Ensure De-gassing Certificate ↓

Check for Gas (LEL by Explosive & Oxy meter) ↓

Check Deficiencies of Components ↓

Fill 2000 ltrs water ↓

Removal of Eduction & Safety Valves ↓

Keep Open to Air for 24 hrs


ROH FLOW PROCESS FOR LPG INSPECTION & REPAIR Circulate Air ↓

Recheck For gas (LEL by Explosive & Oxy meter) ↓

Scrapping/Cleaning of Diaphragm ↓

Fit Repaired Valves ↓

Test Wagon by Pn. Pressure


DOME FITTING -EXTERNAL Eduction Valve Vapour Valve Safety Valve Sampling Valve Magnetic Level Gauge Thermowell Dome Dome Cover


Eduction Valve


EDUCTION VALVE-TROUBLE SHOOTING S. No.

Defect

Reason

Remedy

1

Leakage from Valve base.

Foreign (In Shop) particles Air pressure gasket before Valve fitment. embedded in Air pocket if developed, replace gasket. gasket. Apply torque on stud. On Line Tighten studs bolts with non-sparking tools.

2

Blowing of Valves even in shut off position.

Scales entry into Valve body damaging seat seal .

On Line Tighten spindle to maximum. Secure and tighten safety plug using Teflon tape. Adjust packing nut with non-sparking tools. In Shop Change seat seal. Clean and check body internally for scales. Adjust packing nut.


EDUCTION VALVE-TROUBLE SHOOTING S. No.

Defect

Reason

Remedy

3

Leakage between spindle & stem scales.

Inferior chevron ring. Expired shelf life of rings. Spring broken/Elongated. Packing nut not properly tightened.

On Line Apply M seal layer on layer. Tighten packing nut with non-sparking tools. In Shop Change chevron rings. Change springs. Tighten packing nut.

4

Free movement of spindle.

Retainer nut or stem retainer loose. Breakage of ‘U’ clamp.

On Line NIL-Tighten safety plug with non-

5

Spindle jammed.

sparking tools.

In Shop Tighten nuts. Change ‘U’ clamp.

Mis-matching of Rotate hand wheel slowly alternately threads due to to ‘ON’ & ‘OFF’ position. excess torque by ‘F’ wrench.


EDUCTION VALVE-TROUBLE SHOOTING S. No.

Defect

Reason Impurities while casting these tend to gradually loosen causing body leak later.

Remedy

6

Body leakage.

7

Blowing Damaged ‘O’ from joint of ring. outlet flange.

Change ‘O’ ring.

8

Liquid not flowing even when valve is opened.

Extract gasket piece using hooked stiff wire.

Circular gasket piece stuck in between plug & Eduction Valve flange.

On Line Plug with M seal. In Shop Valve to be condemned.


Safety Valve 1

2

3

Defect

Blowing

Reason

Stem ‘O’ ring defective

Remedy

Change ‘O’ ring.

Defect

Leakage from seat of ‘O’ ring.

Reason

Top lock nut & retainer loose.

Remedy

Tighten Top Lock nut & retainer.

Defect

Valve blowing below 15.85 Kg/cm2.

Reason

Setting defective/spring tension less, spring broken, bottom adjustment nut loose.

Remedy

Reset elongated spring to right tension, change spring, tighten adjustment nut.

Defect

Leakage from under mounting flange

Reason

Defective gasket, foreign particle between gasket & mounting, flange stud loose.

Remedy

Change gasket, tighten stud.


DOME FITTING –INTERNAL •Filling & Empting Pipe •Excess Flow Check Valve

•Sampling Valve •Excess Flow Check Valve •Sampling Pipe

•Magnetic Level Gauging Device •Guide Tube •Retainer Spring •Valve Float •Bumper Spring

•Thermowell Pipe •Support Plate •Funnel Stand


Excess Flow Check Valve


Sampling Valve

1

2

3

Defect

Handle not opening.

Reason

Stem jammed due to corrosion. Thread of stem/body damaged.

Remedy

Open/remove check nut, remove stem, clean with Rustoline, lubricate lightly and refit.

Defect

Blowing in off condition.

Reason

‘O’ Ring damaged

Remedy

Change ‘O’ Ring or seat.

Defect

Sampling not coming out of pipe.

Reason

Sampling tube chocked/Ball valve jammed.

Remedy

Apply air pressure in opp. Direction & lubricate ball valve.


PROBLEM DEFINITION • The increased receipt of NPOH wagons on a continuous basis became a cause of worry as to the reason for this arising in spite of having the same infrastructure and experienced labour force. • The bulk of wagons in NPOH were for leakage from bottom flange of Eduction & Safety Valve.


NPOH WAGONS RECEIVED IN 2007-08 Month

April May June July Aug Sept Oct Nov Dec Jan Feb March Total %age

Total Received in NPOH receipt Receipt Receipt Eduction Safety Sampling Others for % Valve Valve Valve NPOH 52 44 46 122 97 46 85 83 37 98 152 121 983

10 0 12 0 14 20 3 8 5 18 12 4 106 10.78

18.5 0.0 21.1 0.0 13.0 33.9 3.4 9.5 13.2 18.4 7.8 3.3

5 3 7 12 1 5 5 10 5 1 54.0

1 2 4 3 1 2 1 1 15.0

2 2 2 2 1 3 2 14.0

2 5 1 3 2 1 3 4 2 23.0

50.94

14.15

13.21

21.70


DEFECTWISE RECEIPT IN NPOH 60

NO. OF WAGON

54

NO. OF WAGON

50

40

30

23 20

15

14

Safety Valve

Sampling Valve

10

0

Eduction Valve

DEFECTS

Others


PERIOD WISE RECEIPT IN NPOH 23

22

NO. OF WAGON

20

NO. OF WAGON

%

19

19

14

10

5 4 1.93

2.24

2.34

1.93

1.42

0.51

0.41

0 1-3

4-6

7-9

10-12

13-15

PERIOD IN MONTHS

16-18

19-21

00 22-23


MAIN REASON FOR BOOKING NPOH •

Leakage from bottom flange of Eduction Valve. • Leakage from bottom flange of Safety Valve. Defects attributed toi. Improper torque of Studs-loosening studs. ii. Overlapping of Lip & Tongue arrangement. iii. Deepening of groove. iv. Bowing of base flange of Eduction Valve.


IMPROPER TORQUE • RDSO has not prescribed Torque Value for tightening studs of LPG fittings in G-65. Hence, a Torque value was worked out and thereafter a study of Torque distribution was conducted to establish optimum Torque Value of following items for BTPGLN wagon. i. Eduction Valve ii. Safety Valve iii. Manhole Cover Plate


TORQUE VALUE-Calculated by KTTW Component

Bolt Size

No. of Bolts used

Torque in Ft.lb

Eduction Valve

M 20

04

50-60

Safety Valve

M 22

04

100-110

Manhole Cover Plate

M 20

20

160-170


TORQUE VALUE For Eduction Valve


TORQUE VALUE For Safety Valve


TORQUE VALUE For Manhole Cover Plate


TORQUE VALUE STUDY 250 Ft.lb torque was applied for opening the studs of Eduction Valves for following wagons. ACTIVITY NO. OF TORQUE REMARKS WAGON APPLIED POH

16

ROH

21

NPOH

09

250 Ft.lb.

All Studs found intact & could not be opened. Studs opened on less torque on 4 wagons.

Studs are getting loose in NPOH wagons.


TORQUE APPLIED ON EDUCTION VALVE ON POH WAGONS 300

TORQUE in Ft.lb. 250

250

250

250

1

2

3

4

250 250

250

250 250

250

250

250

250

250

250

250

7

8

10

11

12

13

14

15

16

TORQUE

200

100

0

5

6

NO. OF WAGON

9


TORQUE APPLIED ON EDUCTION VALVE ON ROH WAGONS 300

TORQUE in Ft.lb. 250 250 250 250

250 250 250

250 250 250 250 250 250 250 250 250 250 250 250 250 250

TORQUE

200

100

0

1

2

3

4

5

6

7

8

9

10

11

NO. OF WAGON

12

13

14

15

16

17

18

19

20

21


TORQUE APPLIED ON EDUCTION VALVE ON NPOH WAGONS 300

TORQUE in Ft.lb. 250

250

250

250

250

TORQUE

200

200

200

7

8

150

100 100

0

1

2

3

4

5

NO. OF WAGON

6

9


ii. OVERLAPING OF LIP & TONGUE ARRANGEMENT • During fitment of Eduction Valve, some times due to non-alignment of stud the LIP & TONGUE fails to take the précised seating. Since this arrangement is at bottom and not visually seen. It is anticipated that the LIP & TONGUE ARRANGEMENT has interlocked but in reality there is a overlapping which initially seem perfect but during service loosens due to vibration. Thus developing leakage.


iii. DEEPENING OF GROOVE/WORN OUT FLANGE LIP • Continuous corrosion deepens groove with aging of wagon. • Flange lip fails to compress asbestos seat when groove is more than 5 mm deep. • In some cases the flange lip goes below 4 mm due to flange surfacing & filing during servicing of valve.


WORN OUT FLANGE LIP


DEEPENING OF GROOVE-MANHOLE


iv. BOWING OF BASE FLANGE OF EDUCTION VALVE • In some cases, the flange becomes thin due to flange surfacing & filing during servicing of valve. • Thinning of flange leaves a space between flange & Manhole cover. • On tightening four end, an umbrella formation develops which does not allow ring to compress seating or enter into full unison into groove causing a central dome/pocket further causing extra stress and strain on studs in addition to thermal shocks & vibration in service causing further loosening in some cases.


iv. BOWING OF BASE FLANGE OF EDUCTION VALVE


OTHER DEFECTS OBSERVED (Eduction Valve) 1. Porous Flange Ring


OTHER DEFECTS OBSERVED (Eduction Valve) 2. Perforated/Crack Valve Body


OTHER DEFECTS OBSERVED (Eduction Valve) 3. Damaged Teflon Seating


OTHER DEFECTS OBSERVED (Eduction Valve) 4. Damage on Chevron Rings


DEFECTS OBSERVED IN PIPING ARRANGEMENT 1. Heavy Corroded Filling Pipe


DEFECTS OBSERVED IN PIPING ARRANGEMENT 2. Crumbled Magnetic Float


REASON FOR CRUMBLING • Sulphur present in LPG attracts stainless steel and causes walls to erode. The continuous 18.65 Kg/cm2 pressure acts on float due to which float is unable to with stand the pressure and crumbles. • During maintenance, if even a small dent occurs on ball, a concentrator stress develops on dent which becomes a weak spot and acts on ball either at 18.65 Kg/cm2 or 26 Kg/cm2 pressure and the wall crumbles.


DEFECTS OBSERVED IN PIPING ARRANGEMENT 3. Crack at head of Guide Tube


DEFECTS OBSERVED IN PIPING ARRANGEMENT 4. Thermowell Pipe Corrosion/Perforation


REMEDIAL ACTION 1. Improper torque of Studs-loosening studs 1. Calculated Torque value is to be got approved by RDSO. 2. Acquiring of Torque Wrenches & devices. 3. Using of bell wille washers or Lock tight. 2. Overlapping of LIP & TONGUE ARRANGEMENT 1. Counseling & educating staff from time to time. 2. Visual checking the seating by carbon paper method. 3. Using of bell wile washers or Lock tight.


REMEDIAL ACTION 3. Deepening of Groove: 1. Machining of base flange where ever possible to increase the height. 2. Increase the thickness of seating in case of deepening of groove. 3. Development of gauge for measurement of LIP & TONGUE to maintain proper match. 4. Bowing of base flange of Eduction Valve: 1. Machining of base flange where ever possible to remove bow formation. 2. Developing ‘GO’ ‘NOT GO’ gauge for checking excess bow formation.


BARREL PLATE THICKNESS TYPE OF WAGON

COND. SIZE SIDE (minimum)

END (minimum)

TPGLR

11.5 MM

12 MM

BTPGLC

12.5 MM

BTPGLN

12.5 MM

NEW SIZE SIDE (minimum)

END (minimum)

14 MM

16-18 MM

18-20 MM

14 MM

16-18 MM

18-20 MM


c&w  

about lpg wagon

Read more
Read more
Similar to
Popular now
Just for you