What is Pump-Out?

[lana]

Hi everybody,

I came accross the word "Pump-Out" which I could not found in any of my reference books. Any Idea? We have "Pump-Down" which is well known, but "Pump-out"?
Cheers

[afeef]

lana
i never pass by (pump-out),,but i think it is the same meaning of (pump-down)
all regards
afeef

[US Iceman]

lana,

Pump out is a term that has been traditionally used in the industrial refrigeration systems using ammonia. In large central refrigeration systems it can be common to find a small spare compressor, which is called a pump out compressor.

It is as you suspect another term for pump down.

The pump out compressor has the suction line connected to various locations in the refrigeration system.

When a specific area of the system needs to be pumped down for service or line breaking, the pump out compressor is used to evacuate the ammonia from that specific area of the system that has been isolated.

[wambat]

A Typical view: http://www.howecorp.com/CU-SPECS/Pump-out.pdf

[US Iceman]

wambat,

I've seen these before. On some of the very large systems it is not uncommon to see 300-400 CFM compressors used for pump out purposes.

In very low temperature systems using pump out compressors, it is advisable to have the discharge of the pump out compressor also connected to the intermediate pressure to increase the effectiveness.

A recip compressor being used in pump out service cannot draw much of a vacuum at 15 in. HG with a discharge pressure of 180 psig. The discharge temperatures are pretty high also.

If the intermediate pressure is used (for pumping out low temperature systems) the resulting decrease in pressure ratio helps the pump out compressor immeasurably.

OK, you can measure it. But it does help substantially.

[Gwyn]

wow used to have to carry one of those on me van

[wambat]

US ICEMAN Thanks for that, by the way do you also belong to: http://www.eng-tips.com/index.cfm

[lana]

Thanks everybody.