Working principle and structural characteristics of self-operated regulating valve

The working principle of spring-type self-operated pressure regulating valve, taking the rear type of commonly used valve as an example, the initial position of the spool is open, and the pressure P2 after the valve is entered into the upper membrane chamber through the pressure guide tube and acts on the diaphragm of the actuator. When the force is balanced with the force of the spring, the spool position determines the opening of the valve, thus controlling the pressure after the valve. When the pressure P2 behind the valve increases, the force acting P2 on the diaphragm also increases. At this time, the force on the diaphragm is greater than the force of the set spring, so that the spool moves towards the closed position, the opening of the valve is reduced, and P2 is reduced until the force on the diaphragm is balanced with the force of the spring, so that P2 is reduced to the set value. Similarly, when the pressure P2 behind the valve is reduced, the direction of action is opposite to the above direction. The initial position of the spool of the self-operated pressure regulating valve in front of the valve is closed, and the force balance principle is the same as that behind the valve.

Self-supporting regulating valve

The advantages of self-operated pressure regulating valve are simple structure, small maintenance workload, adjustable pressure set point and wide range, which is convenient for users to use pressure balancing mechanism in the continuous regulating valve within the setting range, so that the regulating valve is sensitive, accurate control, allowing large pressure difference to be adjusted medium for light oil, water, air, etc., with low corrosion and fluidity. It can also control non-corrosive gases and vapors below 350 ° C. For high temperature and high degree media, accessories such as condenser and isolation tank should be configured. This product is widely used in natural gas production and transportation, urban heating and metallurgy, petroleum, chemical, electric power and other industries under continuous medium use conditions of regulation and control. However, what will be the control of this product when the amount of media after the valve is reduced, or when there is no amount, or when the amount is interrupted? According to the user's reaction, the regulator will leak, resulting in the differential pressure of the valve before and after the valve is completely equal. When the medium is restarted after the end of the valve is closed, the valve will restore the decompression function, and there is an instant high pressure impact when the pressure is suppressed and then opened. There is a high possibility of damage to the equipment. The following is an application example of our company's product in an enterprise to elaborate the design and application of spring-type self-operated pressure regulating valve (hereinafter referred to as valve) for such special conditions.