Velocity Through Check Valve
Velocity Through Check Valve
(OP)
I have a 20 inch(DN500) pipe with a flow velocity of 4.5 meters per second, I have a few constraints and don't want to go to DN600, what are my options for putting a check valve in this line.
Cheers
Peter
Cheers
Peter





RE: Velocity Through Check Valve
What constraints are you worried about. All swing checks will all be full open at that velocity.
RE: Velocity Through Check Valve
- Check valve Y patter style globe lift (for your velocity your diameter and considering water at 20 °C pressure drop through the valve is approx 0.07 bar)
- Check valve globe lift (for your velocity, your diameter and considering water at 20 °C pressure drop through the valve is approx 1.1 bar)
RE: Velocity Through Check Valve
RE: Velocity Through Check Valve
Regards,
SNORGY.
RE: Velocity Through Check Valve
RE: Velocity Through Check Valve
Conventional wisdom is that a conventional swing check is one of the worst types as they have a large mass of moving parts and disc has a long distance to travel.
DUo check valves can be made to work with heavy springs but this affects the energy losses across the check valve.
For details read
Fluid Transients in Pipeline Systems ARD Thorley
or Pressure Transients in Water Systems by Ellis.
Also check out Delft Laboratories and Utah State University for technical papers on check valves.
You will need to obtain the reverse velocity and deceleration data from a waterhammer analysis and ensure that the check valve parameters meet these requirements without slamming.
The attached presentation has been given to ASME, IMechE and Engineers Australia. Take a look at the notes and references therein.
RE: Velocity Through Check Valve
Can anyone advise how I can calculate the deccelartion rate on a 500NB check valve and a line velocity of 4.6m/s of seawater. Is there an industry accepted empirical formula to calculate this ?
Cheers
Peter
RE: Velocity Through Check Valve
If you mean "emprical" then establish from test the time to close t secs. Then a= 4.6/t m/s^2 & gives you the average deceleration. For a more precise evaluation then have a waterhammer analysis underttaken, preferably using four quadrant data for the pump.