Hi there,

That truly depends on the system. Do you have a PID? Usually a pressure relief valve determines the working pressure of your hydraulic system. ■

Originally Posted by RalfWeiser

Hi there,

That truly depends on the system. Do you have a PID? Usually a pressure relief valve determines the working pressure of your hydraulic system.

As Ralph says; it depends on the system. It also depends on what you are talking about. There is often an unloader valve in a high pressure hydraulic pump which determines its output pressure. A pressure relief valve(s) is stationed downstream of the pump NRV, and any other NRVs, to prevent overload of equipment due to, eg. external loads. So it all depends on what you are aiming for. The best general maxim is to only use hydraulics when you're in a jam! ■

Originally Posted by sganesh

Dear all,

What is the relation in the hydraulic systems between the working pressure and the pressure relief valve set pressure?

Regards,

Greetings and salutations sganesh,

The working pressure of a hydraulic system

has several parts

1. The systems pump flow at low pressure being 100-200 psi and actual pump flow and oil temperature at that pressure which is how all pumps and motors are rated.

Its many parts

The type of pump being gear, vane or piston.

2. The fluid circuit

a. whether the circuit is a cylinder.

b. how big the hydraulic cylinder is and and its piston area

c. whether it is a telescoping cylinder.

d. whether the cylinder is single acting or double acting

3.

b. a work ports involving a hydraulic motor and a detented control valve.

c. the type of hydraulic motor

d. whether the system is open center or closed center.

4. The desired operating pressure and flow of a hydraulic circuit at the systems

recommended oil temperature is one third of the answer, hot hydraulic oil provides

more useable working energy to a fluid circuit; the desired operating pressure

to perform the work desired by the hydraulic cicuit being a cylinder, motor, or pump

is also a part of it; the desired sytem operating pressure is the last part and

the relief valve is set to dump oil if the desired system pressure through that

circuit is to high and could cause injury , death or machinery damage from hose

failures or machinery jamming. The same rules apply for both an open center circuit or a closed center

circuit. ■