Controlled Pressure Receiver Operation

[US Iceman]

Hi Segei.

I'm not quite sure what you are mentioning. Can you elaborate please? Thanks.

[Segei]

I mentioned about low limits on compression ratio. Are these limits apply to screw or recip. compressors? Why?

Thanks
Sergei

[US Iceman]

Each compressor has different issues. For most recip.'s and screws the minimum compression ratio is 2:1. So, if the suction pressure is high like on a CPR system, the minimum discharge pressure may be close to summer design conditions.

Screws you have to worry about oil pressure if they do not have a full time oil pump.

On recip.'s if the compression ratio is too low the explanation I have heard is; the loads on the wrist pin and valve springs can cause accelerated wear.

[Segei]

For screw compressors without oil pump, pressure difference between discharge pressure and suction pressure should be above the minimum limit. Some Frick compressors have 55psig.

[US Iceman]

Yes, which would mean the minimum discharge pressure would be at least 65 psig + 55 psig = 120 psig (using the CPR pressure provided by kooltek). This also means the compression ratio is approx. 1.7 at this condition.

Each application and compressor type may be slightly different. All I'm saying is to check the minimum requirements for operation.

[NH3LVR]

On recip.'s if the compression ratio is too low the explanation I have heard is; the loads on the wrist pin and valve springs can cause accelerated wear.

Can you elaborate or speculate on that a bit?