Five Small Tricks for Handling External Leakage of Electric Control Valves

Method One: Adding Sealing Grease; This method ipplicable to valve bodies that have not yet used sealing grease, where adding sealing grease can be considered to improve the sealing performance of the valve stem. During routine maintenance of electric conlves, adding and replenishing sealing grease is also one of the necessary maintenance procedures.

Method Two: Changing Flow Direction to Position P2 at the Valve Stem End; When the pressure dfference (ΔP) is large and P1 is also high, sealing P1 is obviously more difficult than sealing P2. Therefore, electric control valves can adopt the method of changing the fldirection to switch from having P1 at the valve stem end to having P2 at the valve stem end. This is relatively effective for valves with high pressure and large pressure differences.For example, bellows valves should typically consider sealing P2.

Method Three: Using Lens Gasket Sealing; For the sealing of the upper and lower covers, as well as the sea between the valve seat and the upper and lower valve bodies, if flat sealing is used, the sealing performance is poor under high temperature and high pressure, leading to external leakage. I such cases, switching to lens gasket sealing for the electric control valve can yield satisfactory results.

Method Four: Increasing Packing; This usually involves simply increasing the number of sealing rings by adoptdouble-layer or multi-layer mixed packing form, such as increasing from 3 rings to 5 rings, to improve the sealing performance of the valve stem. However, the leakage preveon effect of electric control valves is not very obvious with this method.

Method Five: Replacing with Graphite Packing; The widely used PTFE packing has an applicable working temperatur range of -20 to 200°C. When the working temperature fluctuates significantly near the upper or lower limits, the sealing performance of the electric control valve drops significantly,ages quickly with a short lifespan. Here, the use of flexible graphite packing is recommended, as it can overcome the difficulties that PTFE packing cannot withstand, offering a longer servife and thus improving sealing reliability. Many factories have completely replaced PTFE packing with graphite packing, and even new purchased control valves are used after replacing their PTFE packing with graphing. However, graphite packing also has a drawback: it has a large hysteresis, and sometimes exhibits stick-slip phenomena initially. Therefore, manufacturers and users should take this into ceration when designing and installing electric control valve equipment.

The above are the solutions for the external leakage phenomenon of electric control valves. For more information on electric control valves, please continuxplore other content.