Electric control valve leakage fault handling methods

Electric control valve with its high precision control, easy installation and commissioning advantages in a variety of industrial control system has been more widely used. However, in the process of using, there are also some problems plaguing the on-site instrumentation personnel, which is the valve leakage problem. Here we discuss the common reasons for leakage of electric control valves and solutions, hoping to help the factory site maintenance personnel a little help. 1, the implementing agencies zero set inaccurate, did not reach the valve all-bit. Adjustment methods: 1) manually shut off the valve (must be confirmed that has been completely closed); 2) re-manual closing of the valve, with a little effort to screw; 3) 4) and then adjust the limit 2, the valve is pushed down to close the type, the thrust of the implementing agencies is not big enough, in the absence of pressure when the debugging is easy to reach the full turn, and the next push, you can not overcome the liquid upward thrust , So off is not in place. The solution: replace the thrust of the implementing agencies, or the balance of spool to reduce the media unbalanced force. 3, the electric valve manufacturing quality caused by the internal leakage valve manufacturer in the production process of the valve material, processing technology, assembly process and other lax control, resulting in seal surface grinding failed, pitting, trachoma and other defects of the product is not completely Removed, resulting in electric valve leakage. Solution: Rework the sealing surface. 4, the electric control valve control part of the internal leakage of the valve leakage control valve is the traditional control valve limit switches, over torque switches and other mechanical control methods, as these control components by the ambient temperature, pressure, humidity, resulting in Inaccurate positioning of the valve, spring fatigue, coefficient of thermal expansion and other objective factors, resulting in electric valve leakage. Solution: readjust the limit. 5, electric control valve debugging problems caused by the internal leakage by the processing, the impact of assembly process, electric control valve prevalence of manual shutdown after the electric open the phenomenon, such as the upper and lower limit switch action position the electric control valve stroke Adjustment smaller, there is not strict control of the electric valve or the valve does not open the exhibition does not extend the ideal state; to adjust the stroke of the electric control valve larger, then caused by the torque switch protection action; if the torque switch action value adjustment Larger, then there crash crash gear or crashed the valve, and even the motor burned accident. In order to solve this problem, usually, the electric regulating valve manually adjust the electric regulating valve to the end during the debugging, and then to open the direction of a circle, set the lower limit switch position of the electric gate, and then set the electric regulating valve to the fully open position. Switch position, so that the electric control valve will not appear after the manual shut down the electric can not open the phenomenon in order to make the electric door open, close freely, but in fact caused the electric door leakage. Even if the electric control valve to adjust the ideal, as the limit switch action position is relatively fixed, the valve control of the medium in the operation of the constant erosion of the valve, wear and tear, can cause valve leakage caused by lax closure. Solution: readjust the limit. 6, the selection error caused by corrosion of the valve cavitation caused by the electric valve leakage cavitation and pressure-related, when the actual pressure difference △ P is greater than the threshold pressure generated cavitation △ Pc, to produce cavitation, empty During the process of bubble burst, huge energy is released, which will have a great damaging effect on the throttling components such as the valve seat and the valve core. Normally, the valve can be operated under cavitation for a maximum of three months or even less, Severe cavitation corrosion, resulting in high seat leakage up to 30% of rated flow above, which is irreparable, therefore, different purposes electric door has different specific technical requirements, according to the system to process a reasonable choice Electric control valve is essential. The solution: process improvement, use multi-stage buck or sleeve valve. 7, the erosion of the media, electric control valve aging caused by leakage within the electric regulating valve adjusted after a certain period of time after the operation, due to cavitation and valve erosion, valve core and seat wear, internal components aging and other reasons, It will appear the electric control valve stroke is too large, electrically adjustable valve lax phenomenon, resulting in greater leakage of electric control valve, with the passage of time, electric regulating valve leakage will be more serious. The solution: readjust the actuator, and regular maintenance, calibration can be.