Key points for use of stacking valve
Key points for use of stacking valve
1. Characteristics of hydraulic system composed of superposition castration
The Superposition valve can form different Superposition valve hydraulic systems according to its different functions. The hydraulic system composed of superimposed valves has the following advantages.
The main disadvantage of the hydraulic system composed of superimposed valves is that there are few circuit forms and small diameter, which can not meet the needs of complex and high-power hydraulic system.
2. Problems needing attention when stacking valves form a hydraulic system
(1) Diameter and installation and connection dimensions. The diameter specifications and installation and connection dimensions of the reversing valve, the stacking valve and the base plate in a group of stacking valve circuits shall be consistent.
(2) Combined with one-way throttle valve. As shown in Figure 121 (a), when the hydraulic control check valve 3 is combined with the one-way throttle valve 2, the one-way throttle valve should be close to the actuator L. On the contrary, if it is configured as shown in Figure 121 (b), when inlet B and outlet a return oil, due to the throttling effect of one-way throttle valve 2, pressure will be generated in section a ~ B of the return oil circuit. When hydraulic cylinder 1 needs to stop, hydraulic control one-way valve 3 cannot be closed in time, and sometimes it will be closed and opened repeatedly, so that the hydraulic cylinder will be impacted.
(3) Combination of pressure reducing valve and one-way throttle valve. As shown in Figure 122 (a), a and B oil circuits adopt throttle valve 2, while B oil circuit adopts the system of pressure reducing valve 3. This system throttle valve should be close to actuator 1. If it is configured as shown in Figure 122 (b), when the oil is fed into port a and returned to port B, the pressure of the oil circuit between the hydraulic cylinder chamber B and the one-way throttle valve increases due to the throttling effect of the throttle valve. This pressure fork is used to control the pressure reducing valve, so that the pressure reducing port of the pressure reducing valve is closed and the outlet pressure becomes smaller, resulting in insufficient pressure to supply the hydraulic cylinder. When the movement of the hydraulic cylinder tends to stop, the pressure in chamber B of the hydraulic cylinder will drop again, the control pressure will decrease, the opening of the pressure reducing valve will increase, and the outlet pressure will also increase. Such repeated changes will make the hydraulic cylinder unstable and produce vibration.
(4) Pressure reducing valve and combination. The system shown in Figure 123 (a) is a system in which hydraulic control check valve 2 is used for oil circuit A and pressure reducing valve 3 is used for oil circuit B. The hydraulic control check valve in this system should be close to the actuator. If it is configured as shown in Figure 123 (b), because the control oil circuit of pressure reducing valve 3 is connected with the oil circuit between hydraulic cylinder chamber B and hydraulic control check valve, the oil in hydraulic cylinder chamber B can leak through the pressure reducing valve, so that the position of hydraulic cylinder at stop cannot be guaranteed, and the significance of setting hydraulic control check valve is lost.
(5) Installation position of speed regulating valve, throttle valve and electromagnetic throttle valve on the oil return circuit. The installation position of these elements shall be close to the main directional valve, so that there will be no back pressure on the circuit after the speed regulating valve, which is conducive to the smooth oil return or leakage of other valves.
(6) Pressure measurement. The pressure gauge switch to be used for pressure measurement shall be placed at the bottom of a group of superposition valves and connected with the bottom plate. A pressure gauge switch is set for the single circuit system; The multi circuit system of centralized liquid supply does not require that each circuit is equipped with a pressure gauge switch. In the circuit with pressure reducing valve, the pressure gauge switch can be set separately and placed in the pressure reducing valve circuit.
(7) Installation direction. In principle, the stack valve shall be installed vertically, and the horizontal installation mode shall be avoided as far as possible. The more components superimposed by the Superposition valve, the greater the mass, and the longer the through bolt for installation. During horizontal installation, under the action of gravity, the bolts will be stretched and bent, and oil leakage will occur between superimposed valves.