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Submergence of dry motor submersible pump 1

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m15

Mechanical
Jun 29, 2006
10
IN
When i came across the dry motor submersible pump the motor has a limitation that it cant be used above 20m.whereas the wet motor submersible pump can be used till 350m.can i know why?pls advice.
 
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I have not got the answer for this submergence hence i posted
 
Is the answer not the dry housing pressure rating? A dry housing would conceiveably have a limitation of 20 m depth, whereas a wet motor could operate presumedly at much greater depths.

If that's not the answer, I don't know what is. We'll see if anybody else can suggest something different.

BigInch[worm]-born in the trenches.
 
Same question asked by ng1709 on 24 Nov. Now is this a strange coincidence or just 3 postings for the same question.




Phitsanulok
Thailand
 
m15:

The answer is the delta pressure. “Wet” motors used in the petroleum industry are installed to depths exceeding 15000 feet (4572 M) without problems. Submerged static pressures > 6000 PSI are not uncommon. The trick is to keep the pressure inside the motor and outside the motor equalized. Dry motors and / or water well type motors are limited by collapse pressure of the motor housing.

D23
 
Very good point. I wasn't considering collapse pressures, as the maximum depth mentioned by the OP was 320 m, but that is probably getting into the depth range where it needs to start being considered for housings without specially designed reinforcement.

BigInch[worm]-born in the trenches.
 
There is also the deltaP across the seals. With oil field type units that are pressure equalized there is no pressure across the seals.

Some water filled water-well motors have limited pressure equalization capacity. They can be used deaper than dry motors, but there are limits.

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