Control Valve Anti-blocking (card) Method (6 Methods) :

- Aug 12, 2020-

1. Cleaning method, welding slag, rust, slag, etc. in the pipeline cause blockage or jam in the orifice, guide part, and balance hole of the lower valve cover, causing strains, scratches and seals on the valve core surface and guide surface Indentations are produced on the surface. This often occurs in the initial commissioning of new systems and after major repairs. This is the most common failure.


2. External flushing method. When using ordinary valves to adjust some media that are easy to precipitate and contain solid particles, the throttle and guide are often blocked. The flushing gas and steam can be externally connected to the bottom plug of the lower valve cover. When the valve is blocked or stuck, open the external gas or steam valve to complete the flushing work without moving the regulating valve and make the valve operate normally.


 3. Install the pipe filter method. For small-diameter control valves, especially ultra-small flow control valves, the throttling gap is extremely small, and there should be no slag in the medium. In case of blockage, it is best to install a filter on the pipe before the valve to ensure the smooth passage of the medium. For regulating valves with positioners, the positioners are not working properly, and the air passage orifice is blocked is the most common fault. Therefore, when working with a positioner, the air source must be handled properly. The usual method is to install an air filter pressure reducing valve on the air source line before the positioner



 4. The method of increasing the throttling gap, such as solid particles in the medium or the welding slag and rust that are washed away in the pipeline because of the failure of blocking or jamming due to the failure of the throttling port, you can use a large throttling gap Throttle components-valve cores and sleeves whose throttle area is a window or opening type. Because the throttle area is concentrated rather than distributed on the circumference, the fault can be easily eliminated. If it is a single or double seat valve, the plunger valve core can be changed to a "V" shaped valve core or a sleeve valve. For example, a double-seat valve in a chemical plant is often stuck. It is recommended to switch to a sleeve valve and the problem will be solved immediately.


 5. The medium scouring method uses the scouring energy of the medium itself to flush and take away the things that are easy to deposit and block, thereby improving the anti-blocking function of the valve. Common methods are: ① change to flow-closed use; ② adopt streamlined valve body; ③ place the orifice in the most severely scoured place, and use this method to pay attention to improving the erosion resistance of the throttle material.


 6. The straight-through is changed to the angle method, the straight-through is inverted S flow, the flow path is complicated, and the upper and lower chambers have many dead zones, which provide a place for the precipitation of the medium. Angular connection, the medium is like flowing through a 90℃ elbow, with good scouring performance, small dead zone, and easy to design streamlined. Therefore, when the straight-through regulating valve is slightly blocked, it can be changed to an angle valve.

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