Electric control valve leakage solution

Control valves play a very important role in the automation of modern plants, whose production depends on the correct distribution and control of the flowing medium. These controls, whether energy exchange, pressure reduction or simple vessel loading, require some final control element to accomplish. Regulating valve is a series of control valves, the main role is to adjust the media pressure, flow, temperature and other parameters, the process control loop in the final element. How to solve the problem of leakage of the electric control valve 1) increase the seal oil law on the unused seal oil motor control valve, consider increasing the seal grease to improve the valve stem sealing performance. 2) Increase the packing method To improve the sealing performance of the packing on the valve rod, increase the packing method. Usually double, multi-layer mixed filler, simply increase the number, such as the 3 to 5, the effect is not obvious. 3) The replacement of graphite packing PTFE used in large quantities, because of its operating temperature in the range of -20 ~ 200 ℃, when the temperature in the upper and lower limits, when the change is large, the sealing will be significantly decreased, aging fast, short life . Flexible graphite filler can overcome these shortcomings and long service life. Therefore, some factories will be all PTFE filler to graphite packing, and even replaced the new control valve which will be replaced by graphite packing PTFE packing used. However, the use of graphite packing back to the large, sometimes some crawling phenomenon, which must be considered. 4) to change the flow, set P2 in the stem end of the law when the larger △ P, P1 and larger, the seal P1 is obviously more difficult than the seal P2. Therefore, the method can be changed to change the P1 in the stem end to P2 At the stem end, this is more effective for valves with higher pressure and larger pressure differential, as is the case for bellows valves. 5) The use of the lens pad seal method for the upper and lower cover seal, valve seat and the upper and lower body seal if the plane seal, under high temperature and pressure, poor sealing, causing leakage, you can switch to the lens pad seal, Can get satisfactory results. 6) Replace the gasket So far, most of the gasket is still asbestos board, at high temperatures, poor sealing performance, short life expectancy, causing leakage. Encountered this situation, you can use the spiral wound gasket, "O" ring, and now many factories have adopted.