This website requires Javascript for some parts to function propertly. Your experience may vary.

no control pressure on GX11 screw compressor | Air Compressor Guide
Join one of my courses on compressed air and air compressors. Click here.


no control pressure on GX11 screw compressor

  • Question Title: no control pressure on GX11 screw compressor
  • Asked by: Guest
  • Asked On:
  • Answers: 1

                        ''A screw compressor can run loaded (‘pumping air’) or unloaded (‘idle’). The inlet/loading valve opens and closes according to air demand. The inlet valve is controlled by a solenoid valve that supplies control air to the inlet/loading valve''

my question how to generate control air?, after servicing ''service stage'' we can't get control air,how to solve this issue....solenoid valve s ok


Compressor Manufacturer: Atlas Copco
Compressor Model: GX11FF-2004 model


Answers & Replies

avatar
Cas

Hi,

Great question! When the compressor is stopped, there's no air pressure, right?! So, where does the control air come from?

All screw compressors have a small by-pass in the inlet valve. So even when it is closed, air is being sucked in and compressed.

Now there's also a blow-off, a small hole that blows off air - usually it blows off just above the inlet valve (between the inlet valve and air filter).

So what happens is that pressure will rise until the same amount of air is blown-off as is sucked in, it's a balance essentially.

The blow-off is usually closed when the compressor runs loaded, to increase efficiency (it's a waste air air really)

There's one more part to this puzzle: the minimum pressure valve. This valve is situated after the separator and before the compressed air outlet of the compressor. It only opens once a certain pressure has been reached. Otherwise, the control air would escape into the piping system.

So if you can't get any control air in your compressor, it could be:

  1. There's no air drawn it at all
  2. The blow-off is too big
  3. The minimum pressure valve is bad (leaking air to outside)

I have added two pictures below of a typical inlet valve in both loaded and unloaded condition, with bypass suction and blow-off.

Please check those things. Would love to hear what the cause was and if you solved it!

Good luck!

UNLOADED:

 

LOADED:

 

Log in or create an account to make a comment...