×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

PRV valve pressure drop

PRV valve pressure drop

PRV valve pressure drop

(OP)
I'm in need of some assistance in calculating some flow vs pressure specifications, in order to make some changes to the system.

I have a PRV valve that has a preset setting of:

PRV NO.1 & 2 SET PRESSURE = 1034 KPA (150 PSI) @ 0.63 L/S (10 USGPM)

Meanwhile the design criteria states the output to be:
PRV NO.1 & 2 OUTLET = 683 KPA (99 PSIG) @ 33 L/S (520 USGPM)
                    = 1034 KPA (150 PSIG) @ 0.63 L/S (10 USGPM)

I'm having difficulty determining or verifying the calculation that will prove that the flow @ 520 USGPM will yield a pressure drop to 99 PSIG, which equals 10 USGPM @ 150 PSIG in this 4" system.

Something just seems odd and I've tried a number of different formula's, obviously not the correct one. I'm hoping to understand what calculation was done, and conduct it again for a flow of 400 USGPM.

The valve is a FORD 4" PRV.

Any help would be appreciated.

Thanks

RE: PRV valve pressure drop

The basic equation for liquid flow across a partially open valve is,

Q = Cv (ρ/ρb) * (δP)  *ρw/ρ)^0.5

Q = flowrate at STP conditions
ρ = density of product at flow conditions
ρw = density of water
ρb = density of product at STP
δP = pressure drop across the valve
Cv = Valve Coefficient at a given percent open.

Did that help?

http://virtualpipeline.spaces.msn.com

"What gets us into trouble is not what we don't know, its what we know for sure" - Mark Twain

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources