Need Advice on High Temperature Tripping of Air Compressor

What's getting hot, and why?

I'd guess that either the rings were put in wrong, or they aren't getting any lubrication.

As i mentioned , its the air temperature after the second stage delivery and before the intercooler.
sorry not to inform before , the compressor is non lubricated air compressor.

I don't know.

Was it doing it before you overhauled it?

Contact info is on the bottom page.

http://www.kajitech.com/DL/Oil_Free_Compressor_en.pdf

It's possible that you are over cooling the pistons and causing condensation which has damaged the seals.....just a guess....check the temp drop 5-10º I believe is spec...check belt tightness, may be too tight....If not, looks like a mistake was made or flaw missed....

http://www.scribd.com/doc/170879636/Handbook-v1-0

You make no mention of any work or replacement of the valves on the compressor. On most recip. type compressors a valve change out is common during a rebuild.

The pressure in the second stage 11 kg/cm2 against 15 kg/cm2 are you saying the amount of compression is lower then spec. this could also indicate a valve problem.

I generally ignore Anonymous Posters, but here goes:

1. Non-lubricated compressors are very unforgiving. If things are assembled a little tight, when they heat up, they get tighter, more heat, more tighter . . . Were OEM parts used, or aftermarket?

2. IsAre the first stage and its intercooler doing their jobs? If not, you can't expect the second stage to make up the difference.

"I generally ignore Anonymous Posters"

I'm still trying to figure out why they're allowed at all.

I'm on an anon diet today

The parameters of the Compressor at the time of tripping are
I st stage : Pressure - 6 Kgf/cm2 and temperature 70 oC
II nd stage : Pressure - 11 Kgf/cm2 and Temperature 100 oC
IIIrd Stage : Pressure - 55 Kgf/cm2 and Temperature 160 oC
Temperature of the air after the Aftercooler of 3 rd stage is : 35 oC
Note all the temperatures and pressures are noted before the intercoolers.
The air temperature after exit of the intercoolers is normal : 35 oC

During the Overhaul , Old Parts are replaced with OEM Parts only.
Need advice on how the clearance affects the temperature and pressure of the outlet air ? What i am asking if the clearance is wrong , the pressure should also increase with temperature rise.

It appears that the second stage is not doing its share of the work, causing the 1st and 3rd to have to make it up. Is 55 Kgf/cm2 the normal discharge pressure? You haven't answered others question regarding valve maintenance. Especially the second stage valves. It may be time to call the manufacturer's service department.

Now you have given some exact values, I would say the inter-stage valves are leaking.

Is there is a chance that the valve components, plates, spacers, etc (during maintenance) have been replaced in the wrong order? - upside down - or bits missing.

The stage pressure of a balanced 3-stage compressor delivering 55 kg/cm2 at the outlet should be about 3, 14 and 55. (from a pressure ratio of 3.87 equal to cube root of 55)

A 1st stage pressure at 6 kg/cm2 gives a pressure ratio of 7.12. Which is very near to 7.4, being the pressure ratio of a two stage compressor delivering 55 kg/cm2.

2-staging means your compressor will be unbalanced and vibrate - witness the noise.

Check for looseness of connecting rods and discharge valves. If the discharge valves plates are damaged, it will result in higher temperature and lower discharge pressure.

Not being familiar with this type Compressor but there is a product we use to solve this sort of problem known as "Plasti-Gage", it may be very helpful to you in finding exact Bearing Surface clearances?

Classic cause of high temperature is inter-cooler failure and/or leaking exhaust valves.

If the 1st stage outlet inter-cooler is not working, then the 2nd stage will compress air that is already hot. The 2nd stage exhaust valve is leaking, thus allowing the now very hot air back from the 3rd stage (reducing the 3rd stge pressure) and getting re-compressed again in the 2nd stage to an even higher temperature.

What was the response when the call went in to the manufacturer's Technical Helpline?

Check the valves,seems like one of the valves are jammed.