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QINSUN interprets the solution to the problem of control valve control system-

Author:QINSUN Released in:2023-05 Click:102

Control valves play an important role in the control system. If the control valve is often stuck or blocked, the control system will not work normally, which will directly affect the advantages of the plant. Therefore, it is very important to fix the problem in time. What methods?

1. Cleaning method

Welding slag, rust and slag in the pipeline cause blockage or blockage in the orifice, guide part and hole balancing the lower valve cover to make the valve Scratches and scratches on the surface of the core and the guide surface, and indentations on the sealing surface. This often happens at the initial stage of commissioning new commissioning systems and after major repairs. This is a common failure. In this case, it must be disassembled and cleaned to remove slag. If the sealing surface is endoground, it must be ground; at the same time, the lower plug is opened to wash the slag falling into the lower valve cover from the balancing hole, and the pipelineFlush. Before commissioning, leave the control valve fully open and fluid flow for a period of time before putting it into normal operation.

2. External flushing method

When ordinary valves are used to regulate some fluids that are easy to settle and contain solid particles, they are often blocked at the port of the valve. choke and guide. Purge gas and steam are connected externally to the plug. When the valve is blocked or jammed, open the external gas or steam valve to complete the flushing work without moving the control valve, so that the valve can work normally.

3. Pipeline filter installation method

For valves de small diameter control, especially ultra-small flow control valves, the throttle gap is extremely small, and there should be no slag in the middle thing. If there is a blockage in this case, install a filter on the pipeline in front of the valve to ensure the smooth passage of fluid. For the control valve used with a positioner, the positioner does not operate normally, and blockage of the gas path orifice is a 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 in the air source line in front of the positioner.

Fourth, increase the choke gap method

For example, solid particles in the medium or welding slag and rust washed into the pipeline cause blockage in rreason of inability to pass through the choke For faults such as jamming, you can use a choke piece with a large choke area - the choke area is a coil or a sleeve with a window or an opening. Since the constriction area is concentrated instead of distributed circumferentially, the defect can be easily eliminated. is excluded. If it is a single or double seat valve, the plunger-shaped spool can be replaced by a \"V\"-shaped spool, or a pinch valve or similar. For example, a double mert valve in a chemical plant is often blocked. Once it is recommended to use a pinch valve, the problem will be solved immediately.

Five, medium scouring method

Using the scouring energy of the support itself, scouring and removing things that are easy to precipitate and block, so as to improve the anti-blocking valve function. Place the holee at the spot where the erosion is severe. When using this method, special attention should be paid to improving the erosion resistance of the orifice material.

Sixth, the straight passage is replaced by the angular method

The straight passage is an inverted S flow, the flow path is complicated, and there are many dead zones in the upper and lower chambers, which provide a place for the medium to settle. Angled connection, fluid appears to flow through a 90°C bend, with good scrubbing performance, small dead zone, and easy to design in a streamlined shape. Therefore, makeWhen a straight-through regul If the shut-off valve is used for light blockage, it can be replaced with a right-angle valve.