Air Release Valves - Drainage Force Main
Air Release Valves - Drainage Force Main
(OP)
I have a drainage pump station with vertical pumps and wanted your commentary on the placement of Air Release/Vacuum Valves. I have added a quick sketch to better illustrate the situation. Will the air release valve by the pump allow air in as flow goes through the drop? The discharge has variable conditions: 1) open discharge and 2) discharge when TW is at ~El. 7. I'm concerned about the head especially when the discharge end is open to atmosphere; will the FM be pressurized?. Any comments are greatly appreciated.





RE: Air Release Valves - Drainage Force Main
The pipe will have some backpressure because of the headloss cause by the high velocity.
You do not need the 2nd air release. Your velocity is relatively high at 10 ft/sec and the velocity will push the air out the end of the pipe.
RE: Air Release Valves - Drainage Force Main
RE: Air Release Valves - Drainage Force Main
If ultimately you decide to put a combo valve at the second location, I suggest sloping the pipe so you have a high point. This allows air to be trapped at the peak and that is where you would locate your air valve.
RE: Air Release Valves - Drainage Force Main
See the attachment.
RE: Air Release Valves - Drainage Force Main
Guess the only consideration left is a vacuum.
RE: Air Release Valves - Drainage Force Main
I will have the first valve be an air release valve only, after all it is a high poiint. My concern was having a combination air release/vacuum, and it allowing air to entrain. For the second valve in the system, closer to the discharge, I will have a combination air release/vacuum valve, as I do need to have a vacuum break to avoid a siphon when pumps turn off, and TW level is high.
Does anyone have any comments/red flags to this setup?
Once again, thank you all!
RE: Air Release Valves - Drainage Force Main