Hydraulic help needed

LD1 · Oct 19, 2021

LouNY said:
Whoops;
corrected the port numbering above.

so supply to port #3
cylinder to port#2
return to tank port #1
With a check valve before the input of port#3
With the pump running and the valve energized flow would be port #3 to port #2,
with a check valve prior to port #3 with the pump shut off the system should hold in that position,
after time the pump could be bumped on to repressurize the system or increase the pressure to further stroke the cylinder,
when the valve is de-energized the fluid will return to tank allowing the cylinder to retract.

I agree this is how it needs plumbed. This gives you THREE functions

1. With Solenoid AND pump energized oil will flow through check valve, into port 3, and out of port 2 to the cylinder to compress the apples

2. With the solenoid energized but NOT the pump...oil will try to come back through port 2 and exit port 3 but wont backspin pthe pump because it will be stopped by the check valve.

3. With the pump off and the solenoid de-energized, the oil will exit the cylinder, travel back through port 2...exit he valve at port 1, and return to tank.

However....if you ever accidently energize the pump and NOT the solenoid, the oil has no where to go. Which is why some people have said you might consider a PRV after the pump. Otherwise the pump would deadhead. Same thing would happen when pressing apples and you get to the end of the stroke. What limits your pressure? How do you know if you are pressing with 1000psi or 6000psi? Does the pump itself have a relief?

kingdaflex · Oct 27, 2021

I have the hydraulic hose for your consideration.

r8f1k · Jul 16, 2022

Ok, so I am finally getting around to doing this.

Supply to port #3
Cylinder to port#2
Return to tank port #1
With a check valve before the input of port#3

"With the pump running and the valve energized flow would be port #3 to port #2,
with a check valve prior to port #3 with the pump shut off the system should hold in that position,
after time the pump could be bumped on to repressurize the system or increase the pressure to further stroke the cylinder,
when the valve is de-energized the fluid will return to tank allowing the cylinder to retract."

The way my tank (10 gal) is currently, it has a return port (1" NPT) at the top of the left side of the tank and then the supply (1"NPT) at the bottom of the right side of the tank. The supply is currently running direct into the hydraulic pump. Based on the new requirements, the supply should go to PORT #3. I assume that I have to put a 'TEE' in the supply line to feed both the pump and PORT #3 on the spool? Please advise