There are three kinds of common faults of regulating valve :1) cleaning method,2) external flushing method, and 3) installation of pipeline filter method

1) cleaning method

The welding slag, rust and scum in the pipeline cause blockage or jam in the orifice, guide position and lower cover balance hole, causing spool surface, guide surface to strain and scratch, sealing surface to produce indentation and so on. This often occurs in the new operation system and after the overhaul of the initial operation. This is a common fault. In this case, it must be removed for cleaning and slag removal. If the sealing surface is damaged, it should be ground. At the same time, open the bottom plug to flush out the slag dropped into the lower cover from the balance hole and flush the line. Before putting into operation, let the regulating valve be fully open, and let the medium flow for a period of time before it is put into normal operation.

2) external scouring method

For some easy precipitation, containing solid particles of medium by ordinary valve regulation, often in the throttle orifice, the direction of the blockage, can be connected to the bottom plug of the valve cover outside the flushing gas and steam. When the valve is blocked or stuck, open the external gas or steam valve to complete the flushing work without moving the regulating valve, so that the valve can operate normally.

3) installation of pipeline filter method

Small diameter control valve, especially the ultra-small flow control valve, the throttle gap is very small, medium can not have a little residue. In case of blockage, try to install a filter on the pipeline in front of the valve to ensure the smooth passage of media. Regulating valve with positioner, the positioner is not working normally, and its air way choke is a common fault. Therefore, when working with the positioner, the air source must be handled well. The method usually adopted is to install the air filter pressure reducing valve in the air source pipeline in front of the positioner.