STRUCTURAL CHARACTERISTICS OF PNEUMATIC CONTROL VALVE

The structure of pneumatic control valve can be divided into two parts: Valve seat, valve hole and valve center. According to their relative position, there are normally closed type and normally open type. 

Valve from the structure can be divided into: cut-off type, sliding column type and sliding plate type of three types of valve. Structure and characteristics of a stop valve the Valve Center of the Stop Valve moves along the axis of the seat to control air intake and exhaust. Figure 4.2 shows the basic construction of the two-way cut-off Valve. In figure 4.2 a, the valve core is pressed against the seat by the spring and gas pressure after the P port of the valve is fed with the working air pressure. The Compressed air can not flow out of the a port. Figure 4.2 b shows the valve core moving downward after the stem is subjected to a downward force, out of the seat, the Compressed air can flow from Port P to Port A. This is the cut-off valve switching principle. The valve shown in figure 4.3 is of the normal type. Figure 4.3a is the initial state, as opposed to figure 4.2A, where the valve center leaves the seat under a spring force and the Compressed air flows from Port P to Port A. Figure 4.3B in working condition, the stem is pressed against the seat to close the valve port, the flow channel is closed, and there is no Compressed air flow from Port A.