Using pumps to transmit energy

[detaildevel]

I am working with a friend of mine to create an underwater propulsion system. My concept is to use an open hydraulic system to allow human generated torque to be converted to water pressure then back into torque to spin a propeller. It my seem counter intuitive, but I actually allows me great flexibility in locating the propeller that I wouldn't otherwise have. Horsepower and RPM are minimal at <2 and 90 respectively.

My question is what type of pump and motor would you recommend to use? True water based hydraulics offer a level of precision, pressure, and torque (not to mention cost) I just don't need. Is there a type of off the shelf pump that could be run backward efficiently as a motor? Eventually I need to build a proof of concept so designing from scratch isn't possible at this point.

 

[detaildevel]

To clarify, when I mention motor I mean like a hydraulic motor not electric. The system will be powered by turning bicycle pedals.

 

[moltenmetal]

Sounds lossy...hope your bicylist is really fit...

 

[detaildevel]

Well part of its purpose is exercise...movement is really just to add a level of entertainment to it.

Since I am not a pump expert I could be wrong, but aren't hydraulic systems extremely efficient (90+%)?

 

[BigInch]

If you can spin them at 3600+ rpm. Got a big gear ratio in mind?

"I think it would be a good idea."
- Mahatma Gandhi (1869-1948),
when asked about Western civilization

 

[detaildevel]

In the context of this system, will a rotary motor not just mimic the forward movement of the pump on a 1:1 basis (or even something close)?

 

[hydtools]

Sounds like reinventing the wheel. Why not direct mechanical drive?

http://www.recumbents.com/WISIL/hpb/compact_drive.htm

Ted

 

[detaildevel]

Direct mechanical drive is difficult to keep simple because there needs to be a fair bit of adjustability as to where the pedals are in relation to the propeller. For example, instead of pedaling it you may want to use your arms to turn the crank.

I have considered that same perpendicular pulley/vbelt setup as well as other flexible shaft solutions, but none offer the simple ability to reconfigure.

 

[hydtools]

See what was done with bicycles:

http://forums.hydraulicspneumatics.com/eve/forums/a/tpc/f/8621030121/m/3841006821

Ted

 

[Artisi]

Sustained power output from the pedalling action such as a push bike will be far far less than the 2 hp you are looking for. Do an internet search to find out.

 

[BigInch]

1/4 to 1/3 HP output for 15 minutes would be a reasonable estiamate.

"I think it would be a good idea."
- Mahatma Gandhi (1869-1948),
when asked about Western civilization