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Wet Pit submersible pumps - Cooling shroud

Wet Pit submersible pumps - Cooling shroud

(OP)
Hi Guys,

We are under a big dilemma now. Need your kind inputs please.

The submersible pumps ordered is to be cooled using pumping fluid which is ambient temperature. Although we can also supply external water (continuous flow) & filling the cooling shroud to cool the pump motor.

Now, somewhere there happened a grave mistake by specs being overlooked which actually asked for an independent internal cooling shroud. Meaning the cooling fluid is independent of the pumping fluid.

When checked with the manufacturer, they are unable to modify the existing design in any means. Should we do it ourselves, its a big void of warranty which is also a risk.

Ive been exploring ways of handling this & came out with an option. Fabricate a stand with an air-tight tank filled with water.

Apologies & polite note. The pump model is only taken as a reference from catalogues & we don't represent any brand in specific.

Do you have any suggestions please.

Thank you

RE: Wet Pit submersible pumps - Cooling shroud

Who overlooked the cooling shroud, you or the pump supplier?

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: Wet Pit submersible pumps - Cooling shroud

(OP)
Its me.

RE: Wet Pit submersible pumps - Cooling shroud

The issue is that the shroud is presumably intended for cooling water separate to the process fluid?.

Your design apart from having no pressure to drive the fluid will rapidly heat up as there is only a finite volume of water in the tank.

Can't you just take a tap off the discharge pipe and then flow through the shroud and discharge into your wet pit? Not sure what flow you need but it can't be a large amount to bypass?? You would need an orifice plate or some sort of control valve once you know fro the vendor what the cooling water flow rate is.

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

RE: Wet Pit submersible pumps - Cooling shroud

Sell the pump you already have and purchase a unit to spec. with a cooling shroud.

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: Wet Pit submersible pumps - Cooling shroud

(OP)
Hi @Artisi,
Unfortunately,that's the last choice we could take. Since there are couple of approvals to get through which is the toughest. The way we are looking forward for now is to explore on how we could modify the existing pump.

Hi @Littleinch,
No, the shroud has a multiple purpose. there is a 2 way valve in the pump.
1. The cooling shroud is circulated with pumping fluid to take the heat away.
2. The cooling shroud is filled with external fluid which is rotated and flushed into the process fluid.

"Your design apart from having no pressure to drive the fluid will rapidly heat up as there is only a finite volume of water in the tank
Can't you just take a tap off the discharge pipe and then flow through the shroud and discharge into your wet pit? Not sure what flow you need but it can't be a large amount to bypass?? You would need an orifice plate or some sort of control valve once you know fro the vendor what the cooling water flow rate is"
I guess you are referring to point 1. If Yes, we can't consider this option since the spec calls for independent cooling fluid other than process fluid.
The fluid is circulated using the pump impeller only.

RE: Wet Pit submersible pumps - Cooling shroud

Lots of luck with rework, probably void all warranties with the on going problems.

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: Wet Pit submersible pumps - Cooling shroud

techky,

I'm now lost.

Your OP said you had made an error and obtained a pump with an independent cooling shroud instead of one which used the process fluid.

The key here is this "Meaning the cooling fluid is independent of the pumping fluid.". I believe that what you actually mean is that the ...cooling fluid MAY BE independent of...

The pump doesn't really care where it get cooling fluid from so long as it's good enough. you stated in the OP "The submersible pumps ordered is to be cooled using pumping fluid " and that you made an error in accidentally specifying a pump with a separate shroud.

So do that - just take a tap off the pumped supply and use that as cooling fluid.

Your (incorrect) specification allows you to use different cooling fluid - it doesn't say you NEED to. If the pumped fluid is within specification for the cooling fluid then use it.

Or use your external supply "we can also supply external water (continuous flow) & filling the cooling shroud to cool the pump motor".



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

RE: Wet Pit submersible pumps - Cooling shroud

(OP)
Hi Litteinch,

Your OP said you had made an error and obtained a pump with an independent cooling shroud instead of one which used the process fluid.
Yes

The key here is this "Meaning the cooling fluid is independent of the pumping fluid.". I believe that what you actually mean is that the ...cooling fluid MAY BE independent of...
Sorry let me clarify. The specification is drafted as "Pump motors shall have a built-in cooling system. The pumped medium shall not be used for cooling the pump motor"

The pump doesn't really care where it get cooling fluid from so long as it's good enough. you stated in the OP "The submersible pumps ordered is to be cooled using pumping fluid " and that you made an error in accidentally specifying a pump with a separate shroud.

So do that - just take a tap off the pumped supply and use that as cooling fluid.

Your (incorrect) specification allows you to use different cooling fluid - it doesn't say you NEED to. If the pumped fluid is within specification for the cooling fluid then use it.

Or use your external supply "we can also supply external water (continuous flow) & filling the cooling shroud to cool the pump motor".
There is a site limitation when it comes to the external supply of water. So that's the reason we are exploring if we could customise the existing design by adding an additional tank.

RE: Wet Pit submersible pumps - Cooling shroud

But you've admitted your spec is not valid for your circumstance and is YOUR document aimed at the VENDOR to stop them simply attaching an internal pipe as part of the package.

I repeat. It is YOUR decision as to whether to use process fluid for cooling or not.

If you need to, amend the specification to read "The pump system shall be designed to allow use of a separate cooling medium flow other than the pumped medium."

Then it's up to you whether you use the pumped medium or not. Problem fixed.

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

RE: Wet Pit submersible pumps - Cooling shroud

What is the fluid being pumped? What different fluid is intended to be used as pumped cooling medium? What is the temperature of each fluid? Check your specifications for an escape clause that would hold the supplier responsible for meeting the specs regardless of your error in approving the submission.

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