Hi guys need some info for a school project On hydraulic directional contrl valves can anyone help please. I need the pros and cons and an application for each of the following directional control valve centres. Fully closed centre 3 and 4 port, fully open, tandem centre and pressure closed with A and B return to tank. Can't find much on the net any info will be much appreciated. Thankyou.
Hydraulic control valves
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oldnslo
Super Member
Closed center: (All four ports blocked)
Typically used with pressure compensated pumps or unloading circuit.
provide some load holding
Cons: Over time will allow a double acting cylinder to extend due to spool leakage.
Motor spool: Port "P" blocked, "A" "B" & "T" connected.
Also requires pressure compensated pump or unloading circuit
Typical use is for motors that are not required to hold a load in position or on cylinder applications with P.O. Check valves on the "A" and or "B" ports.
Tandem Center: "P" & "T" connected, "A" & "B" Blocked
Used with fixed displacement pumps
Typical use is for operating a double acting cylinder where some limited load holding is required.
Can also be used is a series circuit.
Open center: All the ports are connected
Used with fixed displacement pumps
Typical use is for operating motors.
Cons: can not be easily used in a multiple valve system.
Roy
Iplayfarmer
Super Member
Don't leave us hanging now. As you make some progress, keep us posted on this project.
