Hydraulic pump used as a motor?

I assume this is a gear pump? If so, it should work as a motor with pressure applied to what was the output port; in other words you're reversing the flow thru the pump, turning it into a motor.

Whether it will tolerate being reversed by pressurizing the other port depends on the actual construction of the pump. The usual problem with this arrangement is that the shaft seal may be subjected to high pressure, and it may not be up to the job. I'm not real familiar with the construction of gear pumps, so that may or may not be an issue. (Or this may not be a gear pump at all.)

Ned Simmons

I think it is a gear pump. The ports are on the side and when I open them up I can see a gear on the shaft and then another gear right under it meshing with it. The situation is identical for each port. I don't see any kind of check valve in either ports.

The check valves if it has them will be in the seal drain. Some pumps are made to run either direction in this case there will be two check valves for the seal drain so that high pressure isn't applied to the seal. If the pump was just made to be turned one direction only then there will only be one seal drain port and it will be on the suction side of the pump. You might be able to see the seal drain hole in the main ports but often the only way to see them is to take the pump apart. Wayne Cook Shamrock, TX

I don't remember ever seeing this. Does it work like a shuttle to connect the seal cavity to the port with lower pressure?

Ned Simmons

Well the ones that I have seen are simply spring loaded ball check valves built into the casting. But in truth I've not seen that many with that feature. I've seen a lot of pumps that are for one rotation only (often with different sized ports) and these don't need the check valves.

Wayne Cook Shamrock, TX

Could a hydraulic pump/motor and variable pressure accumulator be used to collect the energy of descent of a bicycle and rider, and then by cross-valving, propel them up the other side?

How much might such a system weigh, assuming a pump about 4 inches diameter and

What efficiencies might obtain in such a configuration?

I note that for reference, of 100% potential energy at the top of a say 200 foot hill, coasting to terminal speed, some 10% remains as kinetic energy at the bottom. The rest warms great volumes of air by minute fractions of a degree of temperature.

I seek to capture this energy and use it to light my cigarettes. :)

Yours,

Doug Goncz ( ftp://users.aol.com/DGoncz/ ) Student member SAE for one year. I love: Dona, Jeff, Kim, Mom, Neelix, Tasha, and Teri, alphabetically. I drive: A double-step Thunderbolt with 657% range.