Auxiliary hydraulics

[lt190b]

I am working on a hook up of a hydraulic motor to an excavator. Aux pressure is 3000 psi the flow is 20 gpm. The motor is rated at 2000 psi continuous/2400 psi intermittently and 10 gpm. I have the flow control valve rated for this, my question is about the pressure relief valve. The valve is a RV-4H rated at 30 gpm & 1500-3000 psi relief. The information at surplus center says return can go to any low pressure return line that goes to the tank or can be plumbed directly to the tank. The excavator has a direct to tank valve for use like this, in the aux. hydraulics. Will I need a check valve in the return line as in my sketch? What will the pressure out of the motor be? Will there only be 1000 psi out of the prv? Thanks lt190b View attachment aux hyd.bmp

 

[CalG]

I am working on a hook up of a hydraulic motor to an excavator. Aux pressure is 3000 psi the flow is 20 gpm. The motor is rated at 2000 psi continuous/2400 psi intermittently and 10 gpm. I have the flow control valve rated for this, my question is about the pressure relief valve. The valve is a RV-4H rated at 30 gpm & 1500-3000 psi relief. The information at surplus center says return can go to any low pressure return line that goes to the tank or can be plumbed directly to the tank. The excavator has a direct to tank valve for use like this, in the aux. hydraulics. Will I need a check valve in the return line as in my sketch? What will the pressure out of the motor be? Will there only be 1000 psi out of the prv? Thanks lt190b View attachment 511616

If the return line to tank is large enough to carry the excess flow from the prv AND THE FULL FLOW THROUGH THE HYDRO MOTOR, There will be very little "pressure", No check valve needed, no 1000psi after the prv.

But if there is a restricted line, pressure could build. Remember, PRESSURE is the result of restriction to flow. Pumps can not make pressure, Pumps make volume per rev/ time etc. And open pipes can not hold pressure beyond whatever flow friction is associated.

There WILL BE velocity associated with that fluid flow, and velocity builds pressure rapidly when there are plumbing losses.

KEEP THAT RETURN TO TANK LINE LARGE! Larger than that even ;-)