hydraulic control valve

Hydraulic fluid used to control the pressure, flow and direction components. Wherein the control pressure is called pressure control valve to control the flow of known flow control valve to control the communication, the direction is called off and the flow control valve.By adjusting the flow control valve spool and valve body between orifice area and local resistance it generates flow rate is adjusted to control the velocity of the actuator. Flow control valve use is divided into five kinds. ① throttle: fixed orifice area in tune after the load in a uniform pressure changed little less demanding and motion actuator velocity remained largely stable. ② control valve: pressure changes in load can keep the throttle valve pressure drop is constant. Thus, in the orifice area after it is set, regardless of how the changes in load pressure, control valve can maintain a constant flow through the throttle valve, so Hydraulic tube fittings that the movement of the actuator speed and stability. ③ shunt valve: no matter the load size, can make the same oil source for the two actuators for the same amount to get equal flow diverter valve or sync valve; been prorated for the proportional flow diverter valve. ④ manifold valve: the role of contrast with the diverter valve so that flow manifold Hydraulic pipe fittings. ⑤ flow diversion valve: both shunt valve and manifold valve two functions. Directional control valves use is divided into one-way valve and valve. ① check valve: allows only unidirectional flow in a pipe connected, the reverse is cut off valve ②: Changing between different piping through, broken relationships, based on the work of the spool valve body position in the number of two , three, etc.; according to the number of channels controlled by a two-pass, three, four, five pass, etc.; spool drive under sub manual, mechanical, electrical, hydraulic, etc.. Figure 2 is a three way valve works. The supply port P, O is the return port, A, B is an output port leading to the actuator. When the spool is in the neutral position, all ports cut off, the actuator does not move; when the spool is moved to the right position, P-and A-pass, B, and O-pass; when the spool is moved to the left position, P and B pass , A and O pass. Thus, the actuators can be positive, negative campaign. The late 1960s, in the several hydraulic control valve developed on the basis of electro-hydraulic proportional control valve. Its output (pressure, flow rate) with the input signal can be continuously changed. Electro Hydraulic hose fittingscontrol valve according to different functions, accordingly divided into electro-hydraulic proportional pressure control valves, electro-hydraulic proportional flow control valves and electro-hydraulic proportional directional control valve.