Thursday, 3 April 2014

Compressor and Expressor  failures.

          Compressor and Expressor  failures of Diesel loco shed and action plan to control these failures were discussed with SSE/D/Expressor/.

          28 out of curse attention cases for various compressor sub assemblies and items have been reported by shed since April 2011.The action plan has been prepared to weed out the contributors of low reliability of compressor items. Shed should implement the same and progress report to be furnished through MCDO.

1.           Rubber roller – Total 7 cases of failure of rubber roller have been occurred at an   
            average service life of 9 months. The reason of failure were due to bad quality of   
            rubber  and defective flexible coupling.
1.1        Rubber roller to be checked for physical deformity during pre commissioning of RB  
            and POH locos.
1.2        Analysis of old removed rollers to be done before fitment of new roller. If wear is
           found not  uniform it indicates misalignment.
1.3        Excessive wear indicates poor material quality.
1.4        The entire rollers to be of same hardness.
1.5        Run out of shaft to be checked in M24 and above schedule.      
1.6        Vibration to be checked in all schedules.   
           

2.0        Lube oil pump gear – two nos. gears failed due to poor quality of gear. One from DMW failed in 26 months and the other was M/S KR make that failed in just one month of service life.
2.1       DP test and gear profile check to be introduced from M-12 and above schedule.
2.2       Lube oil pump gear to be replaced in M-24 schedule after lab test.


3.0        After cooler – One after cooler failed due to over aged cooler retained in service.
3.1        Replace after coolers in M 24 schedule.
3.2        After coolers to be Hydraulic tested at 14 Kg/cm2 pressure before fitment.
3.3        Visual checking in every schedule. 


4.0        Liner – One liner failed due to over aged liner retained in service.
4.1        Upgraded liner to be introduced.
4.2        Conventional liner to be replaced in M-12 and above schedule.
4.3        Warranty claim to be raised of released liners if found any abnormality.

5.0        Lube oil Relief valve – Two nos. new relief valves found defective of M/S ELGI     make.
5.1        Relief valves to be replaced with test bench tested one in M4 schedule.
5.2        Poor quality of spring to be reported to OEM.
5.3        Springs to be tested for load deflection.


6.0       Valve -   One valve failed of M /S ELGI make.
6.1       Shed should replace all valves in RB and POH locos with tested valve during 
            commissioning check.
6.2       All valves to be removed and refitted after DP tested in M2 and above schedule.
6.3       Renew valves in M24 sch.


7.0        Flexible coupling – One Flexible coupling failed due to defective material.
7.1        Clamping to be done at end plate of flexible coupling from M12 and above schedule. One special drive to be initiated to provide clamp in all locos.
7.2        Vibration of flexible coupling to be done in every schedule.


8.0        Piston ring – Two cases of piston ring failure reported by shed due to more gaps.
8.1        Piston ring to be replaced in M12 schedule and onward in conventional compressor.
8.2        In upgraded compressor Piston ring to be replaced in M-24 schedule.
8.3        Blow by test to be conducted in M4 and above schedule.
8.4        Warranty claim to be raised for released material.


9.0        HP Piston – Three cases of failure of HP Piston due to defective material
9.1        HP Piston to be replaced in M12 schedule.
9.2        Only zyglo tested piston and wrist pin to be fitted.


10.0      Pipe lines failure – Three locos failed due to old pipe lines fitted during POH resulting air leakage joints.
10.1     All joints of pipelines in RB and POH locos to be checked for thread profiles of couplers and joints.
10.2     Alignment should be checked and fitment should be done by using thread locking compound.
10.3     Condition of clamps to be checked and clamps to be renewed if found bent or crack on welding.
10.4     DPT of coupling and spacer should be done in M24 schedule.


11.0      Intercooler safety valve – Failure was due to less initial thread dia.
11.1     Intercooler safety valve to be replaced with tested one during pre commissioning of RB and POH locos.
11.2     Measurement of thread dia in M4 & above schedule.





12.0      Plug cap – One loco failed for defective plug.
12.1      Condition and thread to be checked by plug gauge before fitment.
12.2      Lab test of plug should be done before fitment.


13.0      Oil indicator - One loco was failed due to defective Oil indicator.
13.1     Oil indicator teeth to be checked by lab from M12 and above schedule.
13.2     Oil indicator to be replaced in M24 and above.

14.0 Other measures for improving reliability of compressor-

14.1.   Correction of AAC
14.2    Categorization of compressor into 'A' & 'B', & 'C' category based on compressor oil 
           consumption. All ‘B’ & ‘C’ category compressors to be attended in next 3 months to  
           upgrade to ‘A’ category.
14.3    Temperature monitoring in every schedule and corrective action in case of 
           abnormalities.
14.4     Sectional monitoring of compressor in every schedule in addition to attention by  
           Mech. Running section.
14.5     Daily one hour training to staffs on quality issues of the section and conduction of     
           Quiz  with proper record keeping.
14.6     Gradation of staffs on the basis of knowledge & skill category into three categories
           as  'A','B','C. The staffs in  ‘B’ & ‘C’ to be upgraded  to ‘A’ category  by intensive
           training in next three months.
14.7     Overdue material retained in service to be listed out and proper action plan to be
            chalk out for replacement phase-wise.
14.8     Proper clamping of all pipelines in M12 and above schedules.
14.9     Bedding test of compressor after overhauling.
14.10   Vibration checking of compressor in all schedules.
14.11   Use of thread locking compound in joints.
14.12    Efficiency test of compressor in all schedules.
14.13    Loading & unloading time to be maintained strictly with in limit.
14.14    RPM Vs MR pressure graph to be plotted to check compressor efficiency.
14.15    Over hauling of compressor sub assemblies in M12 schedule and above for all
             types    of compressor.



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