I have a hydraulic design problem.
There are two hydraulic pipelines, two pumps: one being driven by electric motor, the other by a human by peddling.
I need to join both the flows in one. Both pipes have non-return valves at the end.
The problem is, the pressure by electric motor pump is high(30 bars) and human peddling can't create that much pressure, so the non-return won't allow the flow to go through. Is there any way to increase the pressure or accumulate it(any device that could be helpful).
I think so... Put a accumulator in the system that will only discharge into the shared hydraulic system when to pressure is slightly above that of the hydraulic system. This would likely mean that you need a check valve between the accumulator and the peddle pump. Also a pressure triggered switch between the accumulator and the hydraulic system.Originally Posted by psm1989
I think you will be up against it. This is reminiscent of when I tried to hook two air compressors together. The higher pressure at the time will block the lagging pressure. The pedal can never overcome the non-return valve pressure from the pump holding it closed.
I think you will have to opt for a tiny-tiny pump volume on the pedal so it can reach a similar pressure to the motor. He who has the most pressure delivers the fluid.
It sounds like a slightly bizarre contraption. Care to elaborate?
basically trying to design a bike, electric and human powered. both power would pump hydraulic fluid.
and the fluid will finally be joined into a single outlet, connected to the hydraulic motor which would drive the bike.
would the accumulator work? I mean the pressure variation would be huge and for very long.
I would not say the accumulator idea would not work, but I can't see it. As Pascal points out, the pressure from the pump holding the check valve closed to prevent back-flow to the human, would have to be overcome by the human generated pressure no matter where in the system it all came together.
Given the basis of the project, hydraulics would not, in my Humble O, be the best choice. Hydraulics are not all that efficient at producing speed. They are really good at force though. Generating pressure then converting that back in to a rotational form will suffer quite large losses. Hydraulic motors or rotators are for heavy work and low speeds like forklift wheels etc.
If you were hell bent on going with hydraulics anyway, and I am not suggesting you should quit hydraulics, then what about the human turning an alternator to supply power to the motor for the pump?
Posting Permissions
Reply With Quote