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Minimum Recirculation Line For Submersible Centrifugal Pumps


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#1 ChemiFreak

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Posted 28 August 2018 - 10:05 AM

Hai all

 

I am working on a slop oil system containing slop oil tank and pumps. The slop oil pump is submersible centrifugal pump.

 

  1. Does a submersible pump require minimum recirculation line?
  2. If required, as a general practice, what should the failure position of the control valves located in pump main discharge line and minimum recirculation line be?
  3. What are the governing factors in determining the failure position of these control valves?

Please do inform if any further information is required.

 

 

Thanks in advance



#2 Rahimzadeh

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Posted 28 August 2018 - 01:28 PM

Dear:

Minimum flow need for preventing pump overheating , for submersible pump which is submersed in pumping liquid ,the pump cooling will be done by pumping liquid, that cases i have seen

best regards



#3 ChemiFreak

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Posted 28 August 2018 - 11:16 PM

Dear Rahimzadeh

 

Thanks for the information.

 

Regards

R. Mohan Babu



#4 SawsanAli311

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Posted 29 August 2018 - 01:31 PM

Hi,
Generally submersible pumps are providing recirculation lines to prevent stagnation conditions. That’s what we provided for some of the submersible pumps in drain drums.

#5 ChemiFreak

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Posted 30 August 2018 - 02:33 AM

Hai SawsanAli

 

Could you please elaborate on the cause of stagnation condition and the requirement of circulation line to prevent it?

 

Thanks and Regards

R. Mohan Babu



#6 SawsanAli311

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Posted 02 September 2018 - 01:00 PM

Hi, 

 

We have had lessons learnt from our facilities operation of having sludge accumulation inside the drain drum boot and decide accordingly to provide the re-circulation lines, not related to pump minimum flow as they are submerged. 

 

regards, 



#7 thorium90

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Posted 03 September 2018 - 05:44 AM

If sludge accumulation is the problem, might I suggest to design the pit to be capable of preventing sludge accumulation and then this issue about submersible pump recirculation lines becomes a moot point? 

I think the question about recirculation lines with their valve failure positions etc. is overthinking the problem.

 

If sludge is the problem, why not just solve the sludge problem?

Maybe I don't understand the problem so I have oversimplified the answer, but maybe the solution is alot simpler than what is being discussed here.






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