Self-operated control valve, also known as self-operated control valve, is a new type of control valve. As its name implies, it does not need external power supply and secondary instruments. It relies on the pressure and temperature of the medium flowing through the valve itself to drive the valve to work automatically. It uses the feedback signals (pressure, pressure difference, temperature) from the output of the valve to pass through. The signal tube is transmitted to the actuator to drive the disc to change the opening of the valve, so as to achieve the purpose of regulating pressure, flow and temperature.
According to the structure and function, self-regulating valves can be generally divided into: self-regulating temperature valve, self-regulating pressure valve, self-regulating flow valve and so on, which can be applied to most fluid media for automatic regulation. It can effectively convert the energy of the fluid medium itself into driving force, thus controlling the opening and closing of the valve.
When the medium fluid flows through the valve seat before throttling, it is converted to pressure behind the valve. Then, the upper chamber is input through the pipeline to act on the top tray, and the force produced will be equal to the reaction force of the spring. This determines the relative position of the spool valve seat, so as to control the pressure behind the valve. When the pressure behind the valve increases, the force acting on the top plate also increases, making the spool close to the seat position, so that the gap between the spool and the seat decreases, and the pressure behind the large valve with variable flow resistance decreases. Until the action force on the top plate is balanced with the spring reaction force, the pressure behind the valve is reduced to the preset value. When the pressure behind the valve decreases, the direction of action is contrary to what has been said before. This is the work flow of the self-operated control valve.