It is good for understand hydraulics valves basic knowledge.

1. Telescopic cylinder

2. Check valve

3. Check valve circuit

4. Pilot operated check valve

5. Shuttle valve

6. Pressure control valve
Relief valve
Reducing valve
Unloading valve
Sequence valve
Counter balance valve

14. Pressure relief valve

17. Guided poppet design/Differential
piston

18. Explode view Pilot operated PR
valve

19. Open / Closed position pilot
operated PR

20. Used of PR

21. Construction Pilot operated PR

22. Compound /pilot operated pressure
relief valve

23. Remote piloting/multiple pre. selection

24. Venting Pilot operated PR

26. Valves
Directly operated pressure reducing valve

27. Valves
Directly operated pressure reducing valve

28. Direct operated pre. Reducing valve

29. Valves
Directly operated pressure reducing valve
1 - állító elem, 2 - vezérlő vezeték, 3 - nyomórugó,
4 - vezérlő tolattyú, 5 - vezető él,
1 – adjusting element 5 – governing edge 6 - rugótányér + résolaj vezeték Y,
7 - visszacsapó szelep, 8 - mérőpont
2 – governing line 6 – spring plate and leakage line
3 – spring 7 – check valve
4 – governing spool 8 – measuring point

30. Pressure reduction valve circuits

31. Pilot operated reduction valve

32. Multifunction pressure control

33. Uses of multifunction pre. Control valve

34. Bi-directional pressure regulation circuit
3 3
2
2 1
1
(a) (b)

35. Multi-pressure regulation circuit
2 3
to system
to system
4
2
to system
1
3
1
(c )
(a) (b)
Bi-stage pressure regulation circuit and multi-stage
pressure regulation circuit can reduce overflow power loss.

36. Sequence valves
Sequence valves cause a hydraulic system to operate in a
pressure sequence.
They are used to control the order of various actuators of a
hydraulic system.
As soon as the inlet pressure reaches a preset pressure value,
the sequence valve will open and let oil pass to a secondary
circuit.
Sequence valves have two types—direct-acting and pilot-
operated.
They can also be classified as internal control and external
control types according to where the control pressure is from.

37. Sequence valve circuit

39. Sequence valve

40. Pressure Control Valves
One-way sequence valve and counterbalance valve
(a) (b) (c) (d)
(a) One-way internal control sequence valve
(b) One-way external control sequence valve
(c) One-way internal control counterbalance valve
(d) One-way external control counterbalance valve

41. Counter balance circuit

42. Counter balance circuit

43. Unloading valve

44. Summary
No. Pressure Measure and Outlet leakage symbol
valve control quantity port to
p p
1 Pressure Inlet pressure tank to have no K
relief drain port T T
2 Unloading Pilot pressure tank to have no
p
K
valve drain port T
3 Pressure Outlet pressure actuator to have a P1
reducing drain port L
valve
P2
4 Sequence Inlet/pilot actuator to have a P1
L
K
P1
L
valve pressure drain port P2 P2
5 Counterba Inlet/pilot tank to have no
P P
K
lance pressure drain port
T T
6 Pressure Inlet port
switch pressure