How to handle internal and external leakage of electric valve controller?

In the daily use of electric valve controller, often encounter a variety of failures, electric valve controller leakage is the most common one of many failures, and the leakage of electric valves generally have internal leakage and leakage of two situations! So what's the difference? The internal leakage of electric valve controller, generally refers to when the electric valve is completely closed, there are still media from the flow of electric valve outlet outflow, leakage or drip and so on, popular point, is not strictly closed, sealed bad! The cause of the failure is usually caused by the erosion of the media, or the impurities.

Even if the electric valve screw (STEM) is tightened in place, there is still a gap between the spool and the valve body, the media can flow past. The external leakage of the electric valve controller, generally refers to when the electric valve is completely closed or opened, the external sealing part of the electric valve filler, the leakage of the media appears. That is, the electric valve controller is connected with the connection flange or the connection thread, the seal is not strict, thus causes the media to discharge the connection seal surface, or the stem and glen (that is, valve stem on the pressure packing gland) between the leakage of the media, or the valve body blank on the external leakage caused by trachoma, as well as due to the media erosion caused by the valve body wear out of the leakage.