SAB 110 Screw Compressor -High Suction Pressure

[verstep]

I have problem with my Sabroe compressor Model SAB 110 having high suction pressure and low oil pressure. The starting pressure goes to 6 Bar even increased the capacity it will not lower to 4 BAR and oil pressure 5 bar - normal is 8 bars as expected. When the capacity raise to 100% the oil temperature will reach to 65C discharge goes to 85C also. I checked the suction and oil filter everything is okay.

Is there any possibility that the rotor has problem or the sliding valve?

Please give me inputs about this matter.Any help is highly appreciated

[Tycho]

is this during normal operation, or during startup after the plant has not been used in a while?

if it's after a long standstill, you need to close the suction valve till it's only 1/2 turn open and try to keep the suction pressure between 1 and 2 bar before gradually opening the suction valve, keeping an eye on the oilpressure.

if the suction pressure is too high you wont get oilpressure.


if it's during normal operation, try closing the suction valve while the compressor is running, if it still wont go below 4 bar it might be broken if it cuts out on the LP switch it should be fine

[Tycho]

How'd it go?

[verstep]

Thanks for that reply. Well I tried that one before.The suction valve opened almost around 1/4 open, nothing changed but when i opened 1/4 the liquid valve there is a increase in oil pressure. It only makes the discharge temperature highter and the oil. When I checked the oil color black but no acid present. Water only .02 percent. Is it normal?

I almost check everything from the piston of sliding valve, suction strainer and oil filter. Everything is okay. Oil level is okay. I suspected if it is the rotor. Now where waiting for the York Service Contractor to complete overhaul the unit that is also their suspicion.

Any additonal knowledge well appreciated.

[Renato RR]

Does compressor have overpressure valve on the valve plate?It can leak.

Renato

[Tycho]

There is a safetyvalve that shortcuts the Highpressure and suction side of the compressor if someone accidently starts it with a closed highpressure valve... could be that it's leaking