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Closed Drain System


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#1 Falah

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Posted 26 March 2024 - 01:19 PM

Dear friends
Greetings
I have a closed drain system composed of
drum and two submersible centrifugal pumps, l asked the contractor to add minimum flow line for the pumps , but they refused. They said that since pumps start when liquid level in drain drum is high and stop when they liquid level is low, there is no need for the minimum flow line, in addition that the pumps work intermittently not continuously.
I think we need to minimum flow line even with these justifications.

Edited by Falah, 26 March 2024 - 01:19 PM.


#2 latexman

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Posted 26 March 2024 - 01:39 PM

What is the design flow rate of the sump pump?  Will the flow be above minimum flow at high level/pump on and at low level/pump off?

 

I don't think I've ever seen a sump with submersible pump that had a minimum flow line in my 45 years in the chemical industry.  Maybe others have.



#3 breizh

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Posted 26 March 2024 - 05:31 PM

Hi,

Agree with Latexman and your contractor. The cooling is done by the liquid surrounding the pump.

Share with us some info about the pump .

Breizh 



#4 shvet1

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Posted 27 March 2024 - 11:33 PM

Any pump installation is able to overheated. This threat comes from a point where the liquid is pumped to, not from one where it is pumped out.

Tell us more how you are going to use these pumps.


Edited by shvet1, 27 March 2024 - 11:33 PM.


#5 _1angelia23

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Posted 28 March 2024 - 02:17 PM

What is the design flow rate of the sump pump?  Will the flow be above minimum flow at high level/pump on and at low level/pump off?

 

I don't think I've ever seen a sump with submersible pump that had a minimum flow line in my 45 years in the chemical industry.  Maybe others have.

l've seen many, as in link below for instance

https://we.tl/t-THCdxi7XU9

furthermore does it make sense for pump working not continously and  when high level in drain vessel to work less than minimum flow ? i dont think so



#6 latexman

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Posted 28 March 2024 - 02:37 PM

l've seen many, as in link below for instance

https://we.tl/t-THCdxi7XU9

furthermore does it make sense for pump working not continously and  when high level in drain vessel to work less than minimum flow ? i dont think so

  

I cannot access your link.

 

Attached File  link does not work.png   126.11KB   0 downloads



#7 _1angelia23

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Posted 28 March 2024 - 02:57 PM

 

l've seen many, as in link below for instance

https://we.tl/t-THCdxi7XU9

furthermore does it make sense for pump working not continously and  when high level in drain vessel to work less than minimum flow ? i dont think so

  

I cannot access your link.

 

attachicon.gif link does not work.png

try this

https://ibb.co/bbpbF5X



#8 latexman

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Posted 28 March 2024 - 03:14 PM

try this

 

 https://ibb.co/bbpbF5X

 

Sorry, no.

 

Attached File  link does not work.png   129.77KB   0 downloads

 

Update.  My work laptop is heavily protected by our IT.  I can access your link on my iPhone.  I see the minimum flow orifice on the two sump pumps.  How big (flow) are those sump pumps? 



#9 fallah

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Posted 02 April 2024 - 01:38 PM

Dear friends
Greetings
I have a closed drain system composed of
drum and two submersible centrifugal pumps, l asked the contractor to add minimum flow line for the pumps , but they refused. They said that since pumps start when liquid level in drain drum is high and stop when they liquid level is low, there is no need for the minimum flow line, in addition that the pumps work intermittently not continuously.
I think we need to minimum flow line even with these justifications.

 

Hi,

 

Pump minimum flow line, as general, is a facility for pump protection against pump discharge blockage and its requirement doesn't depend on type of pump operation (continuous/intermittent).

In many intermittent pumping systems in which the pump(s) is manually operated by operator and the pumping period isn't too long, the minimum flow line isn't required; but if the pump(s) is automatically started/stopped the minimum flow line may be required.



#10 Falah

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Posted 05 April 2024 - 01:25 AM


Dear friends
Greetings
I have a closed drain system composed of
drum and two submersible centrifugal pumps, l asked the contractor to add minimum flow line for the pumps , but they refused. They said that since pumps start when liquid level in drain drum is high and stop when they liquid level is low, there is no need for the minimum flow line, in addition that the pumps work intermittently not continuously.
I think we need to minimum flow line even with these justifications.


Hi,

Pump minimum flow line, as general, is a facility for pump protection against pump discharge blockage and its requirement doesn't depend on type of pump operation (continuous/intermittent).
In many intermittent pumping systems in which the pump(s) is manually operated by operator and the pumping period isn't too long, the minimum flow line isn't required; but if the pump(s) is automatically started/stopped the minimum flow line may be required.
Thank you, Fallah




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