Thank you for more useful responses. Based on responses to date, I am thinking of getting a premium efficiency, VFD duty, constant torque motor, which seems to provide the answer to my question. I don't need 10:1 turn down. I will be happy with 6:1 turn down capability without overheating...
Thank you all for good comments and responses.
The pump in consideration is a rotary lobe (positive displacement) pump that has flow ranges from 20 gpm (at low rpm) to 200 gpm (at high/full rpm of 60 Hz). The pump is direct driven by a motor through a gear box. The pump supplier says that the...
I have a 40 HP, inverter duty, 1800 rpm motor fitted with VFD for sewage pumping application. Can this motor speed be turned down 6:1, i.e. down to 300 rpm without overheating issues?
I still don't get how I can calculate the resulting pressure from the formula of P1/m1=P2/m2. It seems that the calculation is not as straightforward as I thought.
I have a 1000 gallon air receiver charged at 150 psi.
If I lose 100 gallon air due to consumption, what will be the resulting air pressure in the tank?
I want to know the pressure drop relationship between fixed receiver tank size with initial pressure and resulting pressure due to air withdrawal.
If I were looking for a standard, common sense engineering, I would not have asked for tips in this forum. I am just looking for ideas and experiences of other engineers who might have better suggestions. I appreciate your advice, which I will keep in mind.
The Rubber Duckbill check valve is not the one we are looking for. We need a check valve with open/close limit switches.
Yes, reorienting the pump is an option, but it needs a lot of extra costly piping modifications, which we want to avoid if possible.
I am still looking for past user references based on the short body wafer style swing check valve in sewage applications. I am reasonably positive that this type of valve was used successfully in raw sewage handling pump stations.
Rerouting the pump discharge pipe to a channel above the waterline is not a viable option at this existing facility.
I am still looking for user references based on the short body wafer style swing check valve.
Yes, Red Valve is another option. But its body is quite large compared to the wafer body swing check valve. I will consider Red Valve as a last resort. Thanks.
Thank you, bimr, for the information. I will be contacting those companies and see how they can help. The RitePro makes 42" valve, while Tyco and Cla-Val do not have 42", according to their websites.
I am wondering if anyone has successfully used these wafer swing check valves in raw sewage...
Thanks, itascot. The Bray (Checkrite) check valve is indeed the closest I came across so far. Its web site information is useful, but it still does not provide assurance that it can be used for raw sewage that carries a lot of solids (debris, rags, etc.) that could interfere with the internal...
Thanks for your suggestion, but the problem with the double disc type is the center shaft/pin which is in the way of sewage flow that carries a lot of solids (rags and debris). The double disc is good for water, but not for wastewater. I am hoping that someone with proven past experience would...
Thanks for your tips. The double disc, butterfly style, or motorized knife gate may work, but they are not quite what I am looking for in terms of reliability. The check valve should close almost instantly with the stoppage of flow to prevent reverse flow. I believe there are wafer style (short...
I need a 42 inch swing check valve for raw sewage service. Due to piping limitations, I am looking for a short body (such as wafer style) swing check valve for sewage pumping application. Full size check valve won't fit. Any suggestions (make and model)?
I need a 42 inch swing check valve for raw sewage service. Due to piping limitations, I am looking for a short body (such as wafer style) swing check valve for sewage application. Full size check valve won't fit. Any suggestions (make and model)?