Control Valve Maintenance and Repair

Regulating valve maintenance and general instrument maintenance is similar, can be divided into passive maintenance, preventive maintenance and predictive maintenance. Passive maintenance is a kind of maintenance method when the control valve and other equipment malfunction. Due to equipment failure to maintain, so often cause the production process to stop, even when serious equipment damage or casualties, etc.. Passive maintenance is the maintenance of the production process, preventive maintenance is based on past experience, according to the time to maintain a maintenance method. For example, regular maintenance is a preventive maintenance, it is based on the operation of different equipment to develop the appropriate maintenance schedule, the equipment has not yet appeared when the failure to maintain. Failure occurs without maintenance, therefore, it can greatly reduce the probability of failure. But this method does not maintain the current use of the actual situation of the regulator analysis, often can also use a certain period of time to carry out the control valve for disassembly and inspection, a waste of time and resources. Predictive maintenance from the current use of the control valve data analysis, the forecast of the state of the control valve, so that the control valve to maximize the use of.

First, the daily maintenance of the work content
Daily maintenance work of regulating valve is divided into two parts: roving inspection and regular maintenance.
1 to understand the shift process operator valve operation.
2 check the control valve and the relevant accessories for the supply of energy (gas source, hydraulic oil or power)
3 check the operation of hydraulic oil system.
4 check the control valve of the static and dynamic sealing point is no leakage.
5 check valve connection pipe and joints with no loose or corrosion.
6 check valve with abnormal sound and larger vibration, check the supply situation.
7 check valve action is flexible, whether the change in the control signal changes in time
8 listen to the spool, the valve seat is no abnormal vibration or noise.
9 found the problem in a timely manner to deal with.
10 to do a good job in the record of the inspection tour, and archiving.

Regular maintenance work as follows:
1 regular valve external cleaning work.
2 regular valve packing and other sealing components to adjust sealing parts replaced as necessary to maintain static and dynamic sealing point of the seal.
3 regular lubrication of parts needed to add lubricating oil.
4 regular air or hydraulic filtration system and cleaning of sewage.
5 regular inspection of the connection point, corrosion, when necessary, replace the connector.

Second, regular check valve
Valve predictive maintenance work units have not yet carried out, should conduct regular check valve. Regularly check the work is preventive maintenance work.
According to the different production process, regular check valve should be different calibration cycle. To determine the cycle of regular check valve can be combined with information provided by the manufacturer. At the same time usually can be overhauled in the process of the production process. Some applications in high-pressure regulating valve, pressure drop or corrosive occasions, to shorten the test cycle.
Inspection is the main content of the static control valve performance testing, if necessary, increase the appropriate test items, such as the control valve flow characteristics of the test. Regularly check the need for testing equipment and instruments, but also the need for replacement parts, therefore, usually commissioned manufacturers.

Third, valve repair
Emergency repair valve repair points, regular maintenance and predictive maintenance. Emergency maintenance is the control valve fails, can not meet the requirements of the maintenance process operation. Regular maintenance usually include daily maintenance and overhaul at the same time and Technology Park maintenance. Predictive maintenance is based on the analysis of predictive maintenance, targeted parts of the relevant control valve repair. Emergency maintenance is the control valve failure after the repair, regular maintenance and predictive maintenance is the failure of the valve before the repair. Typically, the control valve for maintenance personnel by the instrument maintenance, regular maintenance and overhaul at the same time of technical personnel by the manufacturer.
A) valve daily inspection and maintenance work include the following contents:
1 the elimination of stress. Improper installation or a combination of various stress. For example, high temperature thermal stress media installation tight. Stress caused by unbalance force. Imbalance in the role of stress in the control valve, the valve stem guide, deformation, and the valve seat can not correctly cause leakage of variation increases. Therefore, routine maintenance should be carried out maintenance work to eliminate stress.
2 remove rust and dirt. Check valve connection pipe rust, welding slag, dirt, etc., should be promptly removed after the discovery. Because the dirt will cause the valve core and valve seat wear, affecting the normal operation of valve. Usually, can be installed in valve before the filter and other filtering devices, and regular cleaning.
3 check valve support. Valve support to various parts of valve is not subject to gravity location. If you support the wrong cause valve stem and the seat can not, so that variation increases, the sealing performance. Therefore, check valve support is appropriate.
4 transmission parts replacement. Control valve and accessories in the transmission parts if part of the wear and tear can be replaced, repair, etc.. In the replacement and repair should ensure that the transmission is flexible, the transmission gap as small as possible.
5 pneumatic amplifier cleaning. Because the instrument uses the dirt in the compressed air to cause the throttling hole of the pneumatic amplifier to be cleaned, the suitable steel wire is used for cleaning and cleaning. When the back is installed, the amplifier diaphragm is evenly provided with a force to prevent the blockage or leakage. The clamping force amplifier gain adjusting ball, prevent resonance.