Self-control valve

Self-control valve, also known as the direct effect of the control valve is a large class does not require additional energy-driven control valve. It is a kind of the measurement, control and executive function together as a whole, the use of energy-driven action control valve controlled object itself, is divided into two categories of direct-acting and with pilot-operated. Direct effect of self-control valve utilization of the process itself or differential pressure to drive the control valve operation is also available. Bulb type detection element temperature conversion pressure, and then drive control valve action. Which is characterized by simple structure, easy to operate, but will cause a voltage drop caused by the outlet pressure of the non-linear Typically, the regulation accuracy of 10% to 20%. Self-control applications with a commanding role of self-control valve is suitable for small pressure drop and flow rate, outlet pressure range of less than 10% of the set pressure.
Self-control valve has a power-saving features, some control less demanding applications are widely applied. Self-control valve actuator casing head of the input signal is the control valve before or after the valve pressure or differential pressure across the valve, or conversion by the bulb pressure signal. The executive body of the structure is similar to the pneumatic diaphragm actuators.3 way air valve
Self-control valve controlled media have certain requirements, For example, the self-pressure control valve controlled medium temperature should be less than a specified value, the media should be clean when the medium temperature is higher, for example, for steam or 150 ° C above the liquid, should be set to the condenser, into the the implementing agencies comparator medium temperature lower than the specified value.solenoid valve actuator
A self-pressure, differential pressure and flow control valves. Self-pressure control valve according to the the take pressure point position of the valve and the valve latter two categories, to take pressure point in front of the valve for constant pressure control valve; take the pressure point for constant back pressure control valve when the valve after . Steam medium, the condenser can be used medium steam condensate to protect access to the medium of film head temperature, degree of in live ambient temperature, avoid damage to the diaphragm. The gas medium, can be directly charged gas film feeding head. Figure 2-16 is a self-pressurepilot valves