I'm an instrument maintenance engineer. I have problem with PCVs are used to control pressure of storage tanks on setting value 10 mbar in our plant. The PCVs deadband is too much. (their type is spring & diaf. with internal bellows made by SOMSON). is there any suggestion for this problem (such as vacuum switches)? by the way using any electrical instrument (pt, valve...) is impossible.

with best regards.

 

Check with fisher PCV. Model no 1190 allow you to set pressure 0.6 mbar for 20.7 bar inlet pressure.

Regards,
Shailesh C Patel
FDC - Control Systems And Instrumentation

 

A very neat setup for this application is to use a pressure regulator followed by a Sonic (critical flow) Nozzle. The Sonic Nozzle will only provide a restricted mass flow rate of N2 which is based on the pressure controlled by the regulator. Since pressure regulators can provide excellent mechanical control, this combination yields a very accurate N2 flow rate, even under upset conditions. Please contact me for additional details.

John Catch
InFLOW, INC.
http://www.inflowinc.com

 

A very neat setup for this application is to use a pressure regulator followed by a Sonic (critical flow) Nozzle. The Sonic Nozzle will only provide a restricted mass flow rate of N2 which is based on the pressure controlled by the regulator. Since pressure regulators can provide excellent mechanical control, this combination yields a very accurate N2 flow rate, even under upset conditions. Please contact me for additional details.

John Catch
InFLOW, INC.
http://www.inflowinc.com

 

One can put together a very neat solution to this control problem, using just two key components; a Critical (or Sonic) Flow Nozzle, and a pressure regulator. The Nozzle will provide a very stable mass flow of N2 which is regulated by the pressure set on the regulator. One additional advantage is that under upset conditions a maximum N2 flow is still guaranteed.

Please see "tech Note" on the "Products" page of our website or contact me if you would like further details.

Regards,
John Catch
http://www.inflowinc.com