4 replies to this topic

[kirang11]

 recip_comp_article-graphic.jpg   48.8KB   6 downloads

 

Sir,

In our reciprocating compressor which is single stage double acting type, oil from crank case is getting accumulated in the area shown with black line in the figure. while on the other side of crank case it is normal. this is causing compressor bearing temperature high in drive end side. what is the reason oil is accumulating. please clear my doubt sir

[MTumack]

There are a good number of possibilities as to why you would have an oil leak and subsequent accumulation in any given part where is should not be; to find out why you would likely have to either have a millwright tear it apart or send it in to the manufacturer for maintenance.

 

I'd assume a seal is leaking for some reason. Perhaps it is past its design life, perhaps it was operated in less than ideal conditions (ie out of its design temperature), perhaps it was faulty, perhaps it was tampered with... etc etc.

 

There are approximately 20 things that could be wrong with about 5-10 reasons why they could have went wrong. We are not all knowing and require more information. What is your compressors Design conditions? What are its current operating conditions? What kind of history does it have of operation? What kind of history does it have of maintenance? etc...

[Art Montemayor]

Kirang11:

 

The illustration you supply is not one of your actual, installed compressor.  It is a drawing from http://www.nord-lock...r-safe-bolting/showing the critical bolting supplied by a company called Nord-Lock Bolt Securing Systems.

 

Therefore, we don’t have any idea of how your compressor’s crosshead is designed and fabricated – and much less lubricated.  Because of the lack of detailed, as-built drawings, operating manual, or photos we can only speculate as to what you have and how it should operate (and drain its oil) while undergoing lubrication.

 

Through the 54 years I worked as an engineer I operated and modified a lot of reciprocating compressors – more than I can remember.  There are basically TWO lubrication methods used for lubricating a horizontal crosshead guide and pin: the splash method and the positive oil pressure method.  I have used both and have favored the latter.  I can only guess that you have the splash method in your machine.  In any event, what you describe is serious and you should resolve the problem before continuing to operate the compressor.

 

All crosshead pieces are enclosed and you don’t tell us how it is that you know the lubrication oil is being dammed up on the head end of the crosshead piece, without draining back into the crankcase where it belongs.  Please explain.  In all horizontal compressors the crosshead piece drains all oil back into the main crankcase – by gravity from both the crank and the head end.  There must exist a channel or connection inside the crosshead piece that drains the head end of oil.  Please describe it.  You should have a detailed drawing of your compressor and an operating + maintenance manual that fully describes the entire lubrication system and how it works.  Refer to the attached document that explains the basics of the lubrication system for a typical crosshead assembly.

 

Be specific.  WHICH compressor bearing is running hot and how do you know this?  Reciprocating compressors don’t have bearing thermometers installed into all bearings except in very special applications.  Do you have such an installation? 

Await reply.

 

 Recip Compressor Crosshead Lubrication.docx   1.17MB   38 downloads

[kirang11]

 IMG_20160108_244107797.jpg   128.09KB   5 downloads  IMG_20151207_154201599.jpg   80.75KB   5 downloads

 

sir, in the first picture this is our compressor, i can see the crosshead since the frame enclosing this section is transparent plastic like material. the lubrication method is we have auxillary oil pump  and main oil pump which takes suction from crankcase then it goes to filter and then to exchanger and back to lubrcation of bearings, crankshaft , and crosshead.

The second picture is the internal system of frame which i took when the frame enclosure was opened. unfortunately i dont have operating manual for this compressor, but i have P&id.only one temperature indicator is given for monitoring compressor bearing temperature. tripping is 90 deg celcius. temperature raised to 75 deg celcius when this problem observed,while normal temperature is around 45-55 degrees

[Designer1]

Dear Kirang,

Can you please supply the type of oil you are using for lubrication of said machine? What I mean is the grade of oil, synthetic, semi or mineral. OEM recommendation.