The hydraulic control valve is the component that controls the direction, pressure and flow of oil in the hydraulic system. With the aid of these valves, can start, stop, components for the implementation of the direction, speed, action sequence and the ability to overcome the load control and adjustment, make all kinds of hydraulic machinery can coordinate to work as required.

 

 

Flow control valve

 

Classification of hydraulic valves:

A [classification by working principle]

 

Hydraulic valve can be divided into switch valve (or through valve), servo valve, proportional valve and logic valve. The switch valve can only work in the set state after setting. This chapter will focus on the most common valve type. Servo valve and proportional valve can control system data continuously or proportionally according to input signal. The logic valve controls the actions of the actuator according to the pre-programmed logic program.

 

B [classification by purpose]

 

Hydraulic valves can be divided into directional control valves (such as one-way and reversing valves), pressure control valves (such as overflow valves, pressure-reducing valves and sequence valves) and flow control valves (such as throttle valves and speed-regulating valves). These three valve also can be combined according to need each other to become the combination valve, such as ChanXiangChuan page sequence valve, one-way throttle valve, electromagnetic relief valve, etc., make its compact structure, simple connection, and improve the efficiency.

 

C [classification by installation connection]

 

According to the installation connection, the hydraulic valve can be divided into:

 

(1) screw type (tubular) installation connection. The valve is connected to the pipe and other components with a screw joint, and is fixed on the tube. This applies to simple hydraulic systems.

 

(2) screw mounting connection. Each oil port of the valve is arranged on the same mounting surface, and the screws are fixed on the connection plate with the corresponding oil port of the valve, and then connected with other components with the pipe joint and pipe; Or screw these valves into a single block with screws.

 

On the different sides of the integration block, communicate the valve components. This installation connection is widely used because there is no need to remove other components connected to the valve.

 

(3) overlay installation connection. The upper part of the valve is connected with the joint surface, the oil ports are respectively on these two sides, and the same size is connected with the oil port of the specification valve. In addition to its own function, each valve also ACTS as an oil channel, and the valve is folded and installed in a loop, so the structure is compact and the resistance loss is small.

 

(4) flange mounting connection. Similar to the screw type connection, only the flange type replaces the screw pipe joint. A large flow system with a diameter of more than 32_. It has high strength and reliable connection.

 

(5) mounting connection. This kind of valve without a single body, composed of valve core and valve set of unit cell instrumentation in instrumentation pieces of preformed hole, fixed with screw connection or cover plate, and through the block of channels connect each cartridge valve circuit, instrumentation pieces have the effect of body and piping. This is a new type of installation connection which ADAPTS to the integration of hydraulic system.

The above: Factors affecting contact resistance in a pressure relay