Drain a pump body for maintenace 2

[zishi]

We have open system like cooling tower loop for chillers including two cooling water pumps. If we have to isolate pump for maintenance,is there any requirement of vent a pump body before opening drain nut of a pump body or can we just open a drain nut?

 

[Artisi]

What is your concern, will the pump/s be pressurised after shut-down, if yes I would suggest "venting" the pressure prior to opening the drain(depending on case pressure - if only a couple of psi probably no 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.)

 

[bimr]

The pump installation should be designed such that you can safely make a line break. You should have a pressure gauge on the pump which will inform you of line pressure. If there is significant pressure, the pressure should be released prior to maintenance activities.

 

[LittleInch]

There should always be a safe method of relieving pressure in a pressure containing device before you remove something like a plug. If not the fluid could squirt out at high velocity either spraying someone -perhaps you - in the face or eyes. Either that or if the plug is quite tight or the volume quite large you could rip off the last bit of the thread as the plug comes to the end of the thread and then the plug becomes a projectile and at best is lost somewhere, but at worst hits someone or some other equipment damaging it. Do you think that's a good idea?

You can easily get vent plugs which are needle type plugs which don't extend all the way. Just fit one of those if you don't want to fit a valve.

You can also get them as part of the plug - see typical here

http://www.technicalspecialties.net/store/Accessories/Vent_Plug_p132.html

or this

http://www.seekpart.com/product/Man...t-T-Bar-bleed-plug-bleeder-valves-366268.html

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Also: If you get a response it's polite to respond to it.

 

[zishi]

Thanks.Is there any possibility of formation of vacuum in pump body for which air admittance is required or not? because it is an open system so i am confused either the air pressure is needed for drainage of a pump?

 

[bimr]

There may be a slight vacuum as the water drains from the pump. However, it will not be significant enough to be of concern.

 

[LittleInch]

zishi - it won't cause a problem with the pump per se, but if the drain plug is small it may not drain properly or "glug" a lot. This takes a bit longer than if air enters above the liquid.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.