Self-regulating valve is used to adjust the process parameters of medium flow, pressure, temperature, liquid level in the field of industrial automation process control. According to the control signal in the automation system, the opening degree of the valve is automatically adjusted so as to realize the adjustment of the medium flow, pressure, temperature and liquid level. First, the self-operated temperature control valve works (heating type) temperature control valve is based on the liquid incompressible and thermal expansion and contraction principle of work. Heating with self-operated temperature control valve, when the controlled object temperature is lower than the set temperature, the temperature of the liquid package contraction, the role of the actuator on the rod to reduce the force, the valve core components under the action of the spring force to open the valve , Increase the flow of heating medium such as steam and hot oil so that the temperature of the controlled object rises until the temperature of the controlled object reaches the set value, the valve is closed, and after the valve is closed, the temperature of the controlled object drops and the valve opens again. Into the heat exchanger, but also to increase the temperature, so that the controlled object temperature is constant. Valve opening size and the controlled object is the actual temperature and the difference between the set temperature. Second, the self-operated temperature control valve works (cooling) Self-operated cooling temperature control valve working principle can refer to the heating with self-temperature control valve, only when the valve core components in the actuator and spring force to open and close with the role of On the contrary, the temperature valve, the body through the cold medium, mainly used in the cooling device in the temperature control. Third, the working principle of self-operated flow control valve is charged with medium inlet valve, the pressure before the valve P1 through the control line input into the membrane chamber, throttled by the throttle pressure Ps input on the membrane chamber, P1 and Ps difference â–³ Ps = P1-Ps is called effective pressure. P1 acting on the diaphragm thrust and Ps acting on the diaphragm thrust difference and the balance of spring reaction to determine the relative position of the valve core and valve seat to determine the flow through the valve. When the flow through the valve increases, that is, â–³ Ps increase, the results of P1, Ps acting on the next, on the membrane chamber, the spool to the valve seat direction, thus changing the flow area between the valve core and seat so that Ps increase, increase the role of Ps on the diaphragm thrust plus spring reaction force and P1 on the diaphragm thrust in the new position balance to achieve the purpose of controlling the flow.
