Electric control valve closed lax treatment

Electric control valve is to regulate the flow of special media valve, the valve based on the measured parameters (such as temperature, pressure, flow, etc.), in order to constant measured parameters for the purpose of automatic control valve opening. Precisely because of the electric regulating valve precision adjustment function, the valve leakage as the weakness of such products.

The following describes several control valve leakage treatment.

1, the implementing agencies zero set inaccurate, did not reach the valve all-bit.

Adjustment method:

1) Manually shut off the valve (must be confirmed that has been completely closed);

2) re-force manually shut off the valve, with a little effort to twist can not move;

3) Then turn back (open the valve) half a circle;

4) Then adjust the limit.

2, the valve is pushed down the type of closure, the thrust of the implementing agencies is not big enough, in the absence of pressure when debugging is very easy to reach all-bit, but there is a thrust, the liquid can not overcome the upward thrust, so off is not in place.

The solution: replace the thrust of the implementing agencies, or to change to a balanced valve spool to reduce media imbalance.

3, electric control valve manufacturing quality caused by the internal leakage, valve manufacturers in the production process of the valve material, processing technology, assembly process, such as lax control, resulting in sealing surface grinding failed to pitting, trachoma and other defects of the product Completely removed, resulting in electric valve leakage.

Solution: Rework the sealing surface.

4, the electric control valve control part of the impact of the internal leakage, electric control valve is the traditional control valve limit switch, over torque switches and other mechanical control methods, as these control elements by the ambient temperature, pressure, humidity, Resulting in inaccurate positioning of the valve, spring fatigue, thermal expansion coefficient is not uniform 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, assembly process, electric control valve prevalence of manual shut down after the electric can not open the phenomenon. Such as through the upper and lower limit switch action position to adjust the travel of the electric control valve smaller, there is not strict control of the electric valve or the valve does not open the non-ideal state; the electric control valve to adjust the stroke larger, it caused Torque switch protection action; if the action torque torque switch to adjust the larger values, there are crashed gearbox drive 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 lap, 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 electric valve leakage, cavitation and pressure related to the valve when the actual pressure difference △ P is greater than the critical pressure to produce cavitation △ Pc, to produce cavitation, Cavitation bubble burst during the release of a huge energy, the valve seat, spool and other throttling components have a tremendous damage, the general valve cavitation conditions up to three months or less running time, that is, the valve suffered To severe cavitation corrosion, resulting in valve seat leakage up to 30% of the rated flow rate above, which is irreparable, therefore, different purposes of electric valves have different specific technical requirements, according to the system process to be reasonable Selection of electric control valve is crucial.

The solution: process improvement, use multi-stage buck or sleeve valve.

7, the media scouring, electric control valve aging caused by internal leakage, electric control 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 , There will be a large stroke electric control valve, electric regulating 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.