The hydraulic valve is an automatic element operated by pressure oil and controlled by the pressure oil of the pressure distribution valve. It is usually used together with the electromagnetic pressure distribution valve, and can be used to remotely control the on-off of the oil, gas and water pipeline systems of hydropower stations. It is commonly used for clamping, controlling, smoothing and other oil circuits. There are two types: direct action type and pilot type, usually pilot type.

classification

Classified according to the control method: manual, electric and hydraulic control.

Classified by function: flow valve (saving valve, speed regulating valve, diversion and collecting valve), pressure valve (overflow valve, pressure reducing valve, sequence valve, unloading valve), direction valve (electromagnetic direction valve, manual direction valve, one-way valve, hydraulic control one-way valve).

According to the installation method: flat valve, pipe valve, superposition valve, screw cartridge valve and cap valve.

It can be divided into manual valve, electric valve, electric valve, hydraulic valve, electrohydraulic valve, etc.

Directional control

It is divided into one-way valve and directional valve according to the use. One way valve: the fluid in the pipeline can only be connected in one way and blocked in the opposite direction. Reversing valve: change the switching relationship between different pipelines. According to the number of working directions of the valve core in the valve body, it can be divided into two directions and three directions; According to the number of controlled channels, it is divided into two channels, three channels, four-way and five way; According to the valve core driving method, it can be divided into manual, motor, electric and hydraulic. In the late 1960s, the electro-hydraulic share control valve was developed on the basis of the above hydraulic control valve. Its output (pressure, flow) can change continuously with the input electrical signal. The electro-hydraulic share control valve is divided into electro-hydraulic share pressure control valve, electro-hydraulic share flow control valve and electro-hydraulic share direction control valve according to different functions.

Pressure control

It is divided into relief valve, pressure reducing valve and sequence valve according to the usage. (1) Relief valve: it can control the hydraulic system to maintain a stable state when the set pressure is reached. The relief valve used for overload protection is called safety valve. When the system is defective and the pressure rises to the limit value of possible damage, the valve port will turn over and overflow to ensure the safety of the system. (2) Pressure reducing valve: it can control the branch circuit to obtain stable pressure, which is lower than the oil pressure of the main circuit. The pressure reducing valve can be divided into constant pressure reducing valve (stable output pressure), constant differential pressure reducing valve (stable input output pressure) and constant ratio pressure reducing valve (a certain share of input and output pressure) according to the different pressure functions it controls. (3) Sequence valve: an actuator (such as hydraulic cylinder, hydraulic motor, etc.) can be manufactured And then let other actuators act in turn.

Flow manipulation

The flow is regulated by the saved area between the valve core and the valve body and the part of the resistance that occurs, and then the movement speed of the actuator is controlled. There are five types of flow control valves, depending on their use. (1) Saving valve: after adjusting the saving area, the movement speed of the actuator with small load pressure change and low requirement for movement uniformity can be basically kept stable. (2) Speed control valve: when the load pressure changes, the pressure difference between the inlet and outlet of the valve can be saved to maintain a stable value. In this way, no matter how the load pressure changes after saving area adjustment, the speed control valve can keep the flow through the saving valve unchanged, and then stabilize the movement speed of the actuator. (3) Diverter valve: no matter what the load is, equal diverter valve or synchronous valve can make two actuators of the same oil source get the same flow; Obtain the share diverter valve that distributes the flow by share. (4) Collecting valve: its effect is opposite to that of the diverter valve, so that the flow into the collecting valve is distributed according to the share. (5) Diverter and collector valve: it has two functions: diverter valve and collector valve.