Proper side of a pump to to place the valve on
Proper side of a pump to to place the valve on
(OP)
All,
I have a curiosity question here. I've been to a few different recreational waterparks and seen the pumping systems that provide the ride waterflow. What I'm wondering is it correct to put the valve on the output or input side of a pump? Right now I'm in China and they're putting all the valves on the input side(picture attached). I'm thinking the best side would be the output side. I was at a park in Australia where too high a horsepower pump was installed without a VFD and the engineer partially closed to the valve on the output side to temporarily stop the cavitation. What is your guys opinion? Is the difference negligible?
I have a curiosity question here. I've been to a few different recreational waterparks and seen the pumping systems that provide the ride waterflow. What I'm wondering is it correct to put the valve on the output or input side of a pump? Right now I'm in China and they're putting all the valves on the input side(picture attached). I'm thinking the best side would be the output side. I was at a park in Australia where too high a horsepower pump was installed without a VFD and the engineer partially closed to the valve on the output side to temporarily stop the cavitation. What is your guys opinion? Is the difference negligible?





RE: Proper side of a pump to to place the valve on
But to answer your question:
1. a valve on the inlet side would be used to isolate the pump from the supply side of the system should you ever want to remove it, so - there is nothing inherently wrong with a valve on the inlet side. But ensure all valves etc are located at least 5 - 10 pipe diameters back from the pump inlet.
2. likewise you need a valve on the discharge side for the same reason - to isolate the pump from the discharge side of the system.
The closing down of the valve on the discharge side of the pump to reduce flow and limit cavitation is a standard "trick" as a temporary measure if a pump has a cavitation problem - if the pump is over-specified for the application then other long term measures need to be considered like a reduction of impeller diameter.
However, you would never close down a valve on the inlet side on an operating pump as you are likely to cause cavitation.
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.)
RE: Proper side of a pump to to place the valve on
I note from your photo that it looks like they have an nrv on the outlet which some bright spark probably thinks does the same job as an isolation valve....
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Proper side of a pump to to place the valve on
Artisi, I did learn from your post but please save the sarcasm for something else. I'm sure what you can glean from a photo is as much a reflection of what is in your head just as much as what is in the photo. Hell, Littleinch spotted something I had to do a double take on and I was there.
RE: Proper side of a pump to to place the valve on
Even then I struggle to see the savings from one isolation valve, but they probably consider pump failure is relatively rare or just replace it overnight.
They may well have a common isolation valve somewhere you can't see to avoid draining a huge volume.
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Proper side of a pump to to place the valve on
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.)
RE: Proper side of a pump to to place the valve on
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Proper side of a pump to to place the valve on
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.)