Auto Recirculation Valves 1

[alwayslearning]

Dear All,

Has anyone used auto-recirculation valves in their pumping systems (see Tyco website:

http://www.tycovalves-na.com/

getlit.asp?lit=ld/YAWMC-0418-US.pdf ). In our plant we use continuous minimum flow for small capacity pumps; for high capcaity pumps, we have a flow control valve to take care of the min. flow. However, in such large pumps ; we also have a min flow line (with a flow restriction orifice) for the startup / pump switching case.

The above was just for your information. My main question is that I want to have feedback from members about their experience with the Auto Circulation valves and the problems they faced (if any).

Best Regards

 

[checman]

I have applied automatic recirculation valves on different applications that have variable flow requirements. (Mostly boiler feed) I used them mostly to extend MTBF on pumps that had high NSS numbers that required minimum flows of more than 25% BEP. The pumps where running off the curve or out of NPSHA trying to satisfy both the recirculation line and maximum system demand. The automatic recirculation valves worked very well for the most part when the right model was chosen and correctly sized.

Major complaints were. 1) When they failed they took the whole system down. 2) You cannot tell how much flow is going through them or where it is going at any given time. Even with three gauges (one before the valve one after the valve and one on the recirculation line) It can be confusing on how much flow is going to the different areas and they must have faith that the valve working correctly. 3) The savings in energy was not enough to pay for the valve and maintaining it.

Regards checman

 

[smckennz]

Hi Alwayslearning

it pays to remember that a pump that is not required can be turned off. While this is not always the case with large pumps, it often is with small ones.

Cheers

Steve