Classification of the control valve

Control valve executive agencies and regulatory agencies portfolio can be composed of various types of control valves. In order to enhance the function of the control valve, and improve the performance of control valves, control valves can also be used with control valve accessories combination to achieve higher control precision to overcome the shortcomings of the control valve dead zone downgrade. The following describes the main control valve type.
(1) through single seat valve shown in Figure 2, through a single seat control valve has a spool and a valve seat. Figure in the stem and the valve plug, actuator, linear displacement drive spool to move through the stem. The upper cover plate for pressing the packing on the valve cover and valve body are connected by bolts, for positioning the center of the valve stem and valve body. The valve seat and the upper valve cap, used to ensure that the center position of the valve body and valve seat, and when the spool is moved to change the flow area of ​​the fluid, thereby changing the manipulated variable, to achieve the function of regulating fluid flow. -Spool-oriented driven by the top. Through single seat valve top and bottom guide and improve the accuracy of the guide. Some small flow through the control valve is normally driven by the seat. Direct access to the single-seat control valve is only one spool and a valve seat, is one of the most common control valve. Its features are as follows:
(1) a small amount of leakage, easy to implement strict sealing and cutting, for example, may be metal and metal hard seal or soft sealing metal with PTFE or other composite materials, the standard amount of leakage 0.0l% C (C rated flow coefficient).direct acting solenoid valves
(2) allowing the pressure For example, DNl00 valve to allow pressure of only 120 kPa.
Flow capacity is small, for example, the DNl00 through the valve flow capacity of only 100.standard air cylinder
4 thrust of the spool due to the fluid medium, i.e. the imbalance force, therefore, in the high differential pressure applications, large diameter, not the use of such control valve.stainless steel pneumatic cylinders