hydraulic valves - directional control valve

Use is divided into one-way valve and valve. Check valve: allows only unidirectional flow in a pipe connected, the reverse is cut off. Valve: change to a different line relationship between the pass ﹑ ﹑ off the spool in the valve body according to the working position of the number of two ﹑ three, etc.; according to the number of channels controlled by a two-way communication ﹑ ﹑ ﹑ Tee Five-way, etc.; tube fitting according spool drive motor sub-manual ﹑ ﹑ ﹑ electric hydraulic, etc.. Figure 2 is a three way valve works. P is the supply port, O is the oil return port, A ﹑ B is a leading actuator output. 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 Tong, A and O pass. Thus, the actuators can be positive ﹑ reverse movement.
The late 1960s, in the several hydraulic control valve developed on the basis of electro-hydraulic proportional socketless fitting control valve. Its output (pressure ﹑ flow) with the input signal can be continuously changed. Electro-hydraulic proportional control valve according to different functions, accordingly divided into electro-hydraulic proportional pressure control valve ﹑ electro-hydraulic proportional flow control valve and electro-hydraulic proportional directional control valve.