Automatically Priming a Centrifugal Pump

[wsmith22]

Does anyone have any background on automatically priming a centrifugal pump? We are having difficulty locating an automatic air vent that is NSF 61 certified for potable water. The available NSF 61 air vents are very large and heavy and out system is subject to vibration.

We have tested a backwards swing check valve to evacuate the air from the casing with some success, however, I have not found where this set-up has been used anywhere on the internet. Another option would be some sort of floating ball check valve but we are limited to NSF 61 certification or stainless steel materials. Maybe a ball/cone style check valve without a spring?

 

[Artisi]

What are you trying to do, there is a big difference between automatically priming a centrifugal pump and venting air from the casing?

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[wsmith22]

When the system is started with an empty tank, we can get the pump to partially prime (approximately to 50 psi) from using the static head in the filling of the tank. The outlet of the system is closed to atmosphere. However, we cannot get the pump up to full system pressure (75 psi) until the outlet valve is opened or a vent is added. Customer does not want to open valves to prime. Therefore we can not reach our high pressure switch setting and the pump will run until someone opens the valve.

 

[Artisi]

What is NFS 61 and why must it be used?

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[wsmith22]

NSF 61 is the standard that is required to be followed in the United States for drinking water components.

 

[Artisi]

OK.
What do others do in this situation, surely you're not the only ever faced with this problem.
You indicated there are valves available that comply but you have a problem (unknown) from vibration and size, can this valve be mounted "off" the pump to eliminate this problem.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[Artisi]

For interest, I checked the net for air-bleed valves for potable water, seems there are plenty available, do they need the standard and is it absolutely necessary that they do - your call on that one.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[georgeverghese]

Does this help

https://www.valmatic.com/Portals/0/brochures/Air_1500.pdf