Oil enters from the left end, and the pressure oil acts on the left end of the valve core. It overcomes the spring force at the right end to move the valve core to the right. The valve port opens and oil flows out from the right end. If oil enters from the right end, the pressure oil and the spring act in the same direction, pressing the valve core tightly. On the valve seat hole, the valve port is closed, and the oil is blocked and cannot pass through.

The pressure loss is small when the forward liquid flow passes through, and the sealing performance is good when the reverse flow is cut off.

Manual reversing valve: The control handle directly controls the movement of the valve core to realize oil circuit switching. The reversing accuracy and smoothness are not high. It is often used in situations where reversing is infrequent and automation is not required.

Motorized reversing valve: also known as stroke valve, it uses a stopper or cam installed on the workbench to force the valve core to move to control the direction of the liquid flow. It has high reversing accuracy and small impact, and is suitable for systems with large speed and inertia.

Electromagnetic reversing valve: It uses the electromagnet to energize and release and directly push the valve core to control the direction of the liquid flow. The thrust is limited and is suitable for small flow systems.

Hydraulic reversing valve: uses the pressure oil in the control oil circuit to change the position of the valve core. It has a large driving force and is suitable for systems with large flow rates.

Electro-hydraulic reversing valve: It is composed of an electromagnetic reversing valve and a hydraulic reversing valve. The electromagnetic reversing valve changes the direction of the hydraulic valve to control the oil circuit and is called a pilot valve; the hydraulic reversing valve realizes the reversal of the main oil circuit. , called the main valve; it combines the advantages of solenoid valves and hydraulic valves, with easy control and large flow.

Direct-acting relief valve: relies on the pressure oil in the system to directly act on the valve core to balance with the spring force to control the opening and closing action of the valve core.

Pilot-operated relief valve: It consists of a pilot valve and a main valve. The pilot valve is actually a small-flow direct-acting relief valve with a poppet valve core.

application

Fixed value pressure reducing valve

Fixed difference pressure reducing valve: After the spring force is adjusted, the pressure difference remains constant, so that the inlet and outlet pressure difference remains at a constant value. It is used for speed regulating valves.

Direct-acting internal control sequence valve: Internal control refers to using the oil inlet pressure of the valve to control the opening and closing of the valve core.

Direct-acting external control sequence valve

Pilot operated sequence valve

Application: As a back pressure valve: connected in series on the oil return path of the actuator, so that the return oil has a certain pressure to ensure smooth movement of the actuator

orifice

Orifice structure

Stiffness: the ability to resist interference from load changes and maintain stable flow

Features and applications: Due to poor rigidity of ordinary throttle valves, the working flow through it is affected by changes in the working load (i.e. outlet pressure) under certain conditions of the throttle opening, and cannot maintain the stability of the movement speed of the actuator, so it is only suitable for working Occasions where load changes are not large and speed stability requirements are not high

Pressure compensation: Take measures to make the pressure difference before and after the throttle valve remain unchanged when the load changes. One is to connect the fixed difference pressure reducing valve and the throttle valve in series to form a speed control valve; the other is to connect the pressure-stabilizing relief valve Connected in parallel with the throttle valve to form overflow throttling

Static characteristics: The minimum working pressure difference should be maintained above 0.4-0.5MPa

Application: Load changes, speed control systems with high requirements on motion stability