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How to adjust the ratio if the pneumatic control valve is not closed tightly


Release time:

2021-08-03

Pneumatic regulating valve is composed of pneumatic actuator and regulating valve. The primary pneumatic actuator transmits signals through the bearing control system and drives the valve core of the regulating valve to adjust the flow, pressure and temperature of the process device. Therefore, it is inevitable that the flow, pressure and temperature will be lax in application. 1. When the output force of the pneumatic actuator is insufficient, the output force of the pneumatic actuator, as the power part driving the valve core of the regulating valve, is greater than the force required when the valve is closed, otherwise it will not be tightly closed. Then why is this situation? The valve core is pushed open by the medium pressure, and the pneumatic regulating valve will form internal leakage. How can this accident be prevented, therefore, users must pay attention to it. When selecting the type, it is necessary to verify the differential pressure value of the process pipeline and ensure that the pneumatic actuator has sufficient output force to close the valve.

How to adjust the ratio if the pneumatic control valve is not closed tightly

Pneumatic regulating valve is composed of pneumatic actuator and regulating valve. The primary pneumatic actuator transmits signals through the bearing control system and drives the valve core of the regulating valve to adjust the flow, pressure and temperature of the process device. Therefore, it is inevitable that the flow, pressure and temperature will be lax in application.
1. When the output force of the pneumatic actuator is insufficient, the output force of the pneumatic actuator, as the power part driving the valve core of the regulating valve, is greater than the force required when the valve is closed, otherwise it will not be tightly closed. Then why is this situation? The valve core is pushed open by the medium pressure, and the pneumatic regulating valve will form internal leakage. How can this accident be prevented, therefore, users must pay attention to it. When selecting the type, it is necessary to verify the differential pressure value of the process pipeline and ensure that the pneumatic actuator has sufficient output force to close the valve.
2. If the type of regulating valve is not correct, it will also lead to the problem of lax closure. The standard pressure difference of each standard regulating valve is different. Sleeve regulating valve and double-seat regulating valve are larger than single-seat regulating valve. The pressure difference of angular stroke V-shaped regulating ball valve and eccentric rotary valve is larger. Under the condition of larger pressure difference, the reasonable type of pneumatic regulating valve and electric regulating valve are extremely important.
In the process of automatic control,Pneumatic control valveQuality failure will cause the automatic control process to lose high-quality regulation, poor flow characteristics will affect the quality of regulation, large leakage and unreliable action will cause the regulation to fail, which will cause great loss in the production process and add labor intensity. Therefore, people pay more and more attention to the selection and use of pneumatic control valves.
The control accuracy of the pneumatic control valve can be reflected by the change of logistics energy and flow rate. The control energy of the control valve can be judged by adjustable ratio. The adjustable ratio refers to the ratio of large flow rate and small flow rate that the control valve can control when the difference between the two sides of the control valve is a fixed value. When the control valve is used in series pipelines, the adjustable ratio is proportional to the square root of the pressure drop ratio, the smaller the control capacity, when there are 2 or more than 2 regulating valves in parallel and work together, it is necessary to pay attention to the degree of bypass. In practical production, in addition to the regulating valve, there are other pipelines, so the pressure difference before and after the regulating valve will change, which is called the operation flow characteristic. There are linear valves, equal percentage valves and parabolic valves in detail, of which equal percentage valves are widely used and have strong adaptability.