Pneumatic butterfly valve is composed of a pneumatic actuator and a regulator. The pneumatic actuator receives signals from the control system, adjusts the spool action of the pneumatic butterfly valve, and adjusts the flow, pressure, and temperature of the process device. Sometimes in use, there will be a situation of not tightly closing, the following is a specific analysis of the reasons for the problems of the pneumatic butterfly valve.
1. The output force of the pneumatic actuator is insufficient.
As the power part that drives the spool of the regulating valve, the output force of the pneumatic actuator is greater than the force required when the valve is closed, otherwise it will not close tightly and the spool will be pressed by the medium pressure, causing internal leakage. Therefore, the pressure difference of the process pipeline must be verified when selecting to ensure that the pneumatic actuator has enough power to close the valve.
2. The spring stiffness of the diaphragm actuator of the pneumatic butterfly valve adjusting device is insufficient.
The pneumatic butterfly valve membrane regulator relies on the force of the spring to close the valve. The driving force required for opening is small, and the force required for closing is greater. It overcomes the pressure difference before and after the regulator. When the force of the spring is not enough to overcome the pressure difference, it will There is a phenomenon that the closure is not tight. To solve this problem, you need to replace a spring with a large stiffness. For example, the original spring has a range of 20-100KPa, then replace it with 40-200KPa or 80-240KPa.
3. Improper selection of pneumatic butterfly valve regulator.
The allowable pressure difference of various regulators is different, and the allowable pressure difference of the sleeve regulator and the double-seat regulator is larger than that of the quarter-turn regulator and the eccentric rotary valve of the single-seat regulator and the V-shaped regulator. When the pressure difference is large, a reasonable selection is very important.
Problems in the use of pneumatic butterfly valves must be solved in time. It is difficult to solve these problems for a long time, which will cause the safety performance of the equipment using pneumatic butterfly valves to deteriorate, and it is even more difficult to solve them in manufacturing.
