Electric leakage valve internal leakage causes and solutions

The electric control valve has been widely used in various industrial control systems due to its high control precision and convenient installation and debugging. However, in the course of use, there are also some problems that plague the field instrument personnel, that is, the valve leakage problem. Here we will discuss the common internal leakage causes and solutions of electric control valves, hoping to help the field maintenance personnel of the plant.

1. The zero setting of the actuator is not accurate and does not reach the full position of the valve. Adjustment method: 1) Manually close the valve (must confirm that it has been completely closed); 2) Manually close the valve with force, with a slight force and no gas to move; 3) Turn back (opening direction) half a turn; 4) Then adjust the limit.

2. The valve is pushed down to close the type. The thrust of the actuator is not big enough. When there is no pressure, the adjustment is easy to reach the full level. When there is the lower thrust, the upward thrust of the liquid cannot be overcome, so it is not closed. Solution: Replace the actuator with a large thrust, or the balanced spool to reduce the media imbalance.

3, the internal leakage caused by the manufacturing quality of the electric control valve

In the production process, the valve manufacturer does not control the valve material, processing technology, assembly process, etc., resulting in unsatisfactory sealing of the sealing surface, and the products of defects such as pitting and trachoma are not completely eliminated, resulting in leakage of the electric control valve. Solution: Rework the sealing surface.

4, the electric control valve control part affects the inner leakage of the valve

The traditional control mode of the electric control valve is through the mechanical control mode of the valve limit switch and the over-torque switch. Because these control elements are affected by the ambient temperature, pressure and humidity, the valve positioning is out of alignment, the spring fatigue and the thermal expansion coefficient are not uniform. Such as objective factors, causing internal leakage of the electric control valve. Solution: Re-adjust the limit.

Regulating valve to increase the throttle gap method

If the solid particles in the medium or the slag and rust that are washed away in the pipeline cannot be blocked or jammed due to the throttle opening, the throttle with a large throttle gap can be used instead. Valves and sleeves of windows and openings can be easily eliminated because their throttle areas are concentrated rather than circumferentially distributed. If it is a single or double seat valve, the plunger valve core can be changed to a "V" shaped valve core, or changed to a sleeve valve. For example, if a chemical plant has a regulating valve that is often stuck, it is recommended to use the sleeve valve to solve the problem immediately.