1) cleaning method Pipe in the welding slag, rust, slag, etc. in the throttle, the guide part, the valve cover under the balance hole caused by blockage or stuck so that the valve surface, the guide surface of the injury and scratches, sealing surface On the indentation and so on. This often occurs in the early delivery of new delivery systems and overhauls. This is the most common failure. In this case, you must uninstall the cleaning, remove the slag material, such as the sealing surface is also damaged should be ground; at the same time the bottom plug open to flush away from the balance hole into the valve cap slag material, and the pipeline Rinse. Put into operation before the valve is fully open, medium flow into the normal operation after a period of time. 2) External scouring method For some easily sedimentation, medium containing solid particles using ordinary valve adjustment, often in the throttle, the guide block, can be flush at the bottom of the valve cover flushing gas and steam. When the valve is clogged or stuck, open the external gas or steam valve, you can complete the flushing work in the case of the valve does not move, so that the valve normal operation. 3) The installation of pipe filter method on the small-caliber control valve, especially the ultra-small flow control valve, the throttle clearance is very small, medium can not have a little slag material. In this case of blockage, it is best to install a filter on the valve before the pipeline to ensure the smooth passage of media. Control valve with locator, locator is not working properly, the air passage choke plug is the most common failure. Therefore, with the locator work, you must handle the gas source, the usual approach is to install the air filter in front of the locator air line pressure reducing valve. 4) Increase the throttling gap method If the solid particles in the medium or the pipe is washed away the welding slag and rust and other overcrowding caused by congestion, stuck and other failures, can be used to throttle large gap section Flow - throttling area for the window, the opening of the spool, sleeve, because of its throttle area rather than the distribution of the circumference, the fault can be easily ruled out. If it is single, two-seater valve plunger can be changed to "V" -shaped spool, or into the sleeve valve. For example, a chemical plant often have a double-seat valve stuck, it is recommended to switch to sleeve valve, the problem was resolved immediately. 5) Medium scouring method uses the scouring energy of the medium itself to scour away and remove the easily sedimentable and clogged things, so as to improve the anti-clogging function of the valve. Common methods are: ①closed for the flow of closed-type use; ② the use of streamlined body; ③ the throttle placed in the erosion of the most powerful, using this method should pay attention to improve the erosion-resistant materials, parts erosion. 6) Straight through to the angle method Straight through the inverted S flow, the flow path is complex, the upper and lower cavity dead zone, provides a place for the precipitation of the medium. Angular connection, the medium flows through the elbow 90, erosion performance, small dead zone, easy to design streamlined. Therefore, the use of straight through the control valve can be slightly blocked when the valve can be changed to make angular use. Sealing performance of the poor five solutions: 1) grinding fine grinding, eliminate traces, reduce or eliminate the seal gap, improve the sealing surface finish, to improve the sealing performance. 2) the use of unbalanced force to increase the seal than the pressure Actuator of the sealing pressure generated by the spool must unbalance force on the valve top-off trend, the spool of sealing force for the two forces subtraction, on the contrary, the spool Resulting in pressure-closing trend, the spool of the sealing force is the sum of the two forces, thus greatly increasing the seal than the pressure, the sealing effect can be increased more than 5 to 10 times more than the previous general dg ≥ 20 single-sealing valve for the previous The situation is usually open type, if the sealing effect is not satisfied, to flow closed, the sealing performance will be doubled.Especially the two-type cut off the control valve, the general should be closed by flow. 3) to improve the actuator sealing force to improve the actuator of the sealing force of the valve core, but also to ensure that the valve is closed, increasing the pressure ratio to improve the sealing performance of the common method. Commonly used methods are: ①moving the scope of work of the spring; ② switch to a small stiffness spring; ③ increase the attachment, such as with locator; ④ increase the pressure of gas source; ⑤ switch actuator with greater thrust. 4) The use of single seal, soft seal method of double seal control valve can be used instead of a single seal, usually can improve the sealing effect of more than 10 times, if the unbalanced force larger should increase the corresponding measures on the hard seal valve Can use soft seal, but also improve the sealing effect of 10 times. 5) switch to a good sealing performance of the valve in the last resort, the switch can be considered with better sealing performance of the valve, such as the ordinary butterfly valve to the use of oval, and then use the cut-off butterfly valve, eccentric rotary valve, Ball valve and the specially designed cut-off valve. Control valve leakage of six solutions: 1) increase the sealing grease method on the unused sealing grease valve, consider increasing the sealing 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 due to its operating temperature range of -20 ~ +200, when the temperature in the upper and lower limits, when the change is large, it significantly decreased the sealing, aging fast, short life expectancy . 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) change the flow direction, set P2 in the stem end method when △ P larger, P1 and larger, the seal P1 is clearly more difficult than the seal P2. Therefore, the method can be changed to change the direction of P1 in the stem to P2 at the stem end, which is more effective for valves with higher pressure and greater pressure difference, such as 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. Control valve vibration of the four solutions: 1) increase the stiffness of the oscillation and slight vibration, increase the stiffness to eliminate or reduce, such as the use of large stiffness of the spring, the use of piston actuators and other options are feasible. 2) Increase the damping method to increase the damping that is to increase the vibration of the friction, such as sleeve valve spool can be used "O" ring seal, with a larger friction graphite filler, which to eliminate or reduce the slight vibration or Have a role 3) to increase the size of the guide to reduce the gap with the general orientation of the shaft valve size are small, all valves are generally larger with the gap, there are 0.4 ~ lmm, which is conducive to the production of mechanical vibration. Slight mechanical vibration can be reduced by increasing the size of the guide to reduce the vibration to vibration. 4) to change the throttle shape, eliminating the resonance method due to the control valve so-called vibration occurred in the high-speed flow, rapid changes in pressure orifice, changing the shape of the throttle can change the vibration source frequency, the resonance is not strong comparison Easy to solve. The specific method is to be within the scope of the opening of the valve core turning 0.5 ~ 1.0mm. For example, a self-operated pressure regulating valve is installed near the factory area of ​​a factory. The whistle of the resonance causes the worker to rest. After the 0.5mm spool surface is dropped, the resonance whistle disappears.