Selecting an Axial Piston Pump for a 1000m Manned Submersible Application

AI Thread Summary
The discussion focuses on selecting an axial piston pump for a manned submersible operating at a depth of 1000m, with specific requirements of a pump head of approximately 410m and a power input of about 18,000W. Concerns are raised about the high power requirement, suggesting it may be excessive for maintaining constant depth, and prompting questions about flow rates and operating assumptions. The participant mentions a flow rate of 50 l/min and expresses confusion over the size and weight of suitable pumps found online. Alternatives such as using compressed gas for buoyancy control are suggested, along with a cautionary note regarding the risks of icing in the lines. The conversation emphasizes the importance of accurate calculations and research in selecting the appropriate pump for the application.
ENGBIO
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So I posted yesterday about appropriate pumps for pumping water out of a ballast tank in a manned submersibles at a depth of 1000m. I decided to switch to an axial piston pump. I got that the require pump head is approx. 410 m and the required power input provided by the pump is approx. 18 000W. My inlet diameter is 2.6 cm and my outlet diameter is 2 cm.

What would be a good axial piston pump I could use?

Thanks!
 
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ENGBIO said:
So I posted yesterday about appropriate pumps for pumping water out of a ballast tank in a manned submersibles at a depth of 1000m. I decided to switch to an axial piston pump. I got that the require pump head is approx. 410 m and the required power input provided by the pump is approx. 18 000W. My inlet diameter is 2.6 cm and my outlet diameter is 2 cm.

Whoa! 18000 watts is far too much if your purpose is only to maintain constant depth with a "trim tank". But if you're talking about diving and surfacing that's a different thing.

What is the flow rate in gallons or ft3 or m3 per second?

One you know the pressures, the flow rates, and the power requirements, why can't you just search the Internet for pumps meeting your specifications? Learning how to use research tools available to you may be part of the lesson your professor wants you to learn.
 
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ENGBIO said:
So I posted yesterday about appropriate pumps for pumping water out of a ballast tank in a manned submersibles at a depth of 1000m. I decided to switch to an axial piston pump. I got that the require pump head is approx. 410 m and the required power input provided by the pump is approx. 18 000W. My inlet diameter is 2.6 cm and my outlet diameter is 2 cm.

What would be a good axial piston pump I could use?
In the previous thread you never nailed down the assumptions much less calculated the operating requirements. Please post a summary of the work you've done to get those answers so we know we aren't just providing meaningless help to move forward with bad critera/calculations.
 
anorlunda said:
Whoa! 18000 watts is far too much if your purpose is only to maintain constant depth with a "trim tank". But if you're talking about diving and surfacing that's a different thing.

What is the flow rate in gallons or ft3 or m3 per second?

One you know the pressures, the flow rates, and the power requirements, why can't you just search the Internet for pumps meeting your specifications? Learning how to use research tools available to you may be part of the lesson your professor wants you to learn.

Hi Anorlunda! My flow rate is 50 l/min or 0.000833333 m^3/s. I did look look online for a dc pump to meet my specifications but the one I found for that power was like 800 lbs lol...So I thought perhaps I was doing something wrong but I guess for that amount of power it would be quite large? Its odd though because how would small manned submersibles be able to accommodate such massive motors.
 
russ_watters said:
In the previous thread you never nailed down the assumptions much less calculated the operating requirements. Please post a summary of the work you've done to get those answers so we know we aren't just providing meaningless help to move forward with bad critera/calculations.

Yes, I apologize I didnt want to clog up the post with my calculations but I'll try to be clearer next time
 
OK, I must have been wrong in what your application is. I thought it was just trim to maintain constant depth.

An 18kw BLDC motor is similar to those used in electric cars. A quick search for those on alibaba showed some 20 kw weighing 39 kg. It might be similar to the motors used for propulsion.
 
How about using compressed gas instead of a pump for gross buoyancy control. A full compressed Nitrogen tank is at 2200psi and a high pressure SCUBA tank is in the 3300-3500psi range.
 
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A caution: be sure to thoroughly dry such air lest an urgent tank-blow cause icing in the lines...
IIRC, this was the probable cause of tragic loss of submarine USS Thresher...
 
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Nik_2213 said:
A caution: be sure to thoroughly dry such air lest an urgent tank-blow cause icing in the lines...
IIRC, this was the probable cause of tragic loss of submarine USS Thresher...
Ahh! So that's what did it. Good thing to note.
 

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