How to model a Combination Pressure Reducing Valve (PRV) and Pressure Sustaining Valve (PSV)?
Cla-Val Model 92-01/692-01 Combination Pressure Reducing and Pressure Sustaining Valve
The following example model requires version V8i SELECTseries 6 of either WaterGEMS, WaterCAD, or HAMMER.
combination PRV PSV example.zip
The above video is simulating a pump shut down.
Stage 1: As the upstream hydraulic grade decreases to 20ft (PSV's minimum hydraulic grade setting), the PRV gradually opens to maintain a downstream hydraulic grade of 10 ft (PRV's maximum hydraulic grade setting). Stage 2: As the downstream hydraulic grade gradually decreases, the PSV gradually closes to maintain an upstream hydraulic grade of 20ft (PSV's minimum hydraulic grade setting).
NOTE: If you are using HAMMER, a transient analysis will not permit three pipes connected to the PSV or PRV. In this case, you will need to insert (split pipe with) an additional node on both sides of the valves (very close to the valve) and connect the bypass pipe to that node instead of connecting directly to the valve.
If you encounter stability problems where the network is unbalanced or you see unexpected results in the area of the combination PRV/PSV, you may need to adjust the advanced calculation options available with the 2.0.012 engine version, such as the Damping Limit. See more here
How does the Pressure Sustaining Valve (PSV) work?How does the Pressure Reducing Valve (PRV) work?Cla-Val Model 92-01/692-01 Combination Pressure Reducing and Pressure Sustaining Valve