3 replies to this topic

[Subject_Name_Here]

Hi all,

I have a rudimentary question about differential pressure and control valves.

In the case of a pressure control valve the inlet pressure is less than the outlet pressure because fluids flow from high to low pressure where the extent of dP is the driving force.

So if I have compressed air for example, with an inlet of 200 psi and reduce the downstream pressure to 100 psi using a control valve, won't there be more flow than if I controlled downstream pressure at 150 psi?

 

Thanks in advance.

[sukanta87]

Hi,

 

Are you sure that the inlet pressure of the PCV is less than the outlet pressure? Usually the inlet pressure of the PCV should be higher than outlet, though it may reverse for back pressure PCV (regulator).

 

Flow from 200 spi to 100 psi is higher than 200 to 150.

[Subject_Name_Here]

No, I apologize, I said that in reverse.

This is odd to me because to reduce the flow down to 100 psi the valve has to close more, correct? Isn't it choking flow by doing this? Or is the venturi principle coming into play now?

And why would a flow control valve not operate the same way? At 100% open the flow and pressure is greater to the process than if I had the valve at 50% open.

[breizh]

To support your work , consider this paper.

 

Breizh