Screw Compressor with Slide valve problems
Screw Compressor with Slide valve problems
(OP)
so here's a problem, or maybe it isn't a problem.
I have a flooded screw type NG compressor that was replaced with a refurb, and now the slide valve is more open (109% from 101% ) than previous and the loading is higher (84% from 71%) and it is also running on higher amps (119 amps from 108 amps). all this is based on a the old data that I have from the previous compressors. Does anyone have any ideas?
I have a flooded screw type NG compressor that was replaced with a refurb, and now the slide valve is more open (109% from 101% ) than previous and the loading is higher (84% from 71%) and it is also running on higher amps (119 amps from 108 amps). all this is based on a the old data that I have from the previous compressors. Does anyone have any ideas?





RE: Screw Compressor with Slide valve problems
RE: Screw Compressor with Slide valve problems
If you are used to seeing the indicator greater than 100% and now it is even farther above 1000% I would expect that the indicator is just shifted a tiny bit.
Valves like a slide valve are extremely non-linear. Going from 10% to 20% will be a flow rate increase several times larger than going from 80% to 90%. In fact I consider any slide valve position over about 85% to be fully open. Machines with turn valves instead of slide valves are slightly more linear, but not a lot.
Were I you I would be more interested in why someone replaced a machine that always runs as unloaded as it can get with the same machine. The only capacity control technique that wastes more energy than a slide valve (or a turn valve) is a recirc bypass. Any way to slow the machine down, lower the suction pressure, or raise the discharge pressure?
David Simpson, PE
MuleShoe Engineering
In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist