×
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

Control Valve Design

Control Valve Design

Control Valve Design

(OP)
Hi All,

If we have a water reservoir (say with a water level of 100m), then 2km of 300mm watermain to a pressure reducing valve, how is the 'maximum allowable pressure drop' across the valve calculated. Just to note that downstream of the Pressure Reducing Valve is a normal water reticulation system with customers.

Im reading http://www.cheresources.com/valvezz.shtml which states that usual rule of thumb is that a valve should be designed to use 10-15% of the total pressure drop or 10 psi, whichever is greater. How would you calculate the total pressure drop in the above example. Is it just 100m minus the head loss in the 300mm watermain upstream of the valve ??

Any assistance would be appreciated.

Mark

RE: Control Valve Design

The rules of thumb apply to most systems but not all.  Let's say you are letting down steam from HP to LP through a control valve.  Since the piping is typically short, pressure drop is minor and the dP for the control valve sizing is the difference between the two steam pressures.

In your case, use the 100 m head minus line losses to calculate the inlet pressure to the control valve (which is also the dP it sounds like).

The 10% to 15% rule (which usually I've seen higher as 1/3) simply doesn't apply in this case.

RE: Control Valve Design

(OP)
Thanks for the reply....

Cheers

Mark

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