Another reason for having a pilot operated unloading valve (or relief or anything pilot) is that it becomes more distinct in when it opens and closes and it has a flatter pressure/flow curve, not affected as much by varying flow.
You could possibly put a sequence valve with external pilot in parallell with the return needle valve and have that sequence valve open from the load pressure.
This Parker valve is a candidate for the job: https://www.partsgopher.com/product/svh102s30/svh102-sequence-valve
Impressive if you can see from the picture that its a gerotor pump. The only one I know is Parker PGG2. Yeah, that wouldn't be my first choice either, standard gear pumps are cheap and easily available.
Looking at that Waterman valve again I think it may be closed center anyways but with a...
Cool machine! Can we get a picture of the pump as well? Not too much of a close up.
My googling gives me nothing on those Waterman valves.
Considering the application I stand by that these are mobile open center valves until the opposite is proven. A 3-port flow controller with a parallel...
BrianPetersen, I agree with what you say. However, the type of 3-port flow control valves that I linked to exists for one reason and one reason only, and that is to slow down functions that run on fixed pumps. Doing the calculations for flow and pressure will tell you if significant heat is...
If the motors have internal drain, it's not a good idea to put the orifice on the outlet side because that will pressurize the shaft seal.
When you have a fixed displacement pump (like your gear pump), you use a 3-port flow control valve instead of a 2-port, it will require less power because...
Yes, I'm very much aware of the double meaning of the word Hydraulic and I'm also very much aware of the use of the term Fluid Power, especially in academia. I've been "googling" white papers for almost 20 years.
That is why I did not omit the "Fluid Power" term from my suggestion I just added...
Because of threads like this one. People see the term Fluid Power for the first time and assume it means all kinds of different things that is not Hydraulics and Pneumatics.
Alex-1985, people are asking about the big picture. It is critical to understand your system so that we can help you.
You are not giving us any information at all which makes it hard to imagine what you are trying to achieve, a lot of guessing.
Here is some key questions, if you answer these we...
"So far I have realized that I need to use a hydraulic proportional valve and adjustable axial piston pump. I understand a little bit about l-s control when the pump changes pressure if the load on the boom changes. But I can't figure out how to forcibly change the boom extension speed when the...
LittleInch, I've never seen the term Pressure Regulating Valve being used for anything other than pneumatic pressure regulators. While the hydraulic version technically does the same thing I don't think you'll find many hydraulic suppliers calling it that. The name most commonly used is pressure...
