Backflow through a PRV

[IronDogg]

I have a quick dumb question; Will a pressure reducing globe valve allow flow in the opposite direction if demand suddenly dictated such?

 

[hydrae]

Depends upon the type and conditions
A direct acting will only if the pressure upstream is less than the set point
Most diaphragm operated pilot controlled globe valves (Cla or equal) will open unless there is a return check feature in the piping or a power chamber type has a disconnect between the two disks.

Hydrae

 

[IronDogg]

Thanks for the reply and the info. Sorry it took a while to reply back.

 

[gerhardl]

If you really need a large backflow for a (larger) pressure reducing valve, you should consider a needle regulation valve. A high-priced, but very flexible solution for a large span of pressure and flow. Can easily be modified or guaranteed for backflow.

 

[IronDogg]

Thanks for the suggestion! You're not kidding about the "high-priced" comment... I looked up a 16", and yeeouch.

 

[gerhardl]

Note on needle valves: Yes, price is high, but lifetime could be very long without any service at all. In addition flow capacity could be high, and a smaller valve with abrupt flange extension could under circumstances be used. Specialist consultation is necessary for dimensioning.