Use and maintenance of electric control valve

Use and maintenance of electric control valve

With the rapid development of China's industry, the electric control valve is more and more widely used in metallurgy, petrochemical industry and other fields, and its stability and reliability are becoming more and more important. Its working state will directly affect the automatic control process. The correct use and maintenance of the electric control valve can not only improve the reliability of process control, but also increase the service life of the electric control valve, It has considerable economic benefits for energy saving and consumption reduction of enterprises. This article will elaborate on the use and maintenance of electric control valve.

Precautions for installation and use of electric control valve

For the newly designed and installed control system, in order to ensure the normal operation of the regulating valve during startup and the safe operation of the system, before the installation of the new valve, check whether the nameplate mark on the valve is consistent with the design requirements. The following items shall also be commissioned.

Basic error limit; Full stroke deviation; Return difference; Dead zone; Leakage amount (in case of strict requirements).

If the regulating valve in the original system is overhauled, besides verifying the above items, the sealing inspection shall also be carried out for the stuffing box and joints of the old valve.

In the field use of regulating valves, many of them are not caused by the quality of regulating valves, but by improper installation and use of regulating valves, such as improper installation environment, installation position and direction, or unclean pipelines. Therefore, pay attention to the following aspects when installing and using the electric control valve:

The  control valve is a field instrument. It is required that the ambient temperature should be within - 25 ~ 60 ℃ and the relative humidity should be ≤ 95%. If it is installed in the open air or at high temperature, waterproof and cooling measures shall be taken. Keep away from the vibration source or add anti vibration measures where there is a source.

Generally, the regulating valve shall be installed vertically, and it can be tilted under special circumstances. For example, when the tilt angle is large or the self weight of the valve is too large, the supporting parts shall be added to protect the valve.

Generally, the pipeline for installing the regulating valve shall not be too high from the ground or floor. When the pipeline height is greater than 2m, a platform shall be set as far as possible to facilitate the operation of the hand wheel and maintenance.

Before the installation of regulating valve, the pipeline shall be cleaned to remove dirt and welding slag. After installation, in order to ensure that no impurities remain in the valve body, the valve shall be cleaned again, that is, all valves shall be opened when the medium is introduced to prevent impurities from getting stuck. After using the hand wheel mechanism, it shall be restored to the original neutral position.

In order to make the production process continue in case of failure or maintenance of the regulating valve, the regulating valve shall be equipped with a bypass pipeline.

At the same time, special attention shall be paid to whether the installation position of the regulating valve meets the requirements of the process.

The electrical part of the electric control valve shall be installed according to the construction requirements of relevant electrical equipment. Explosion proof products shall be installed according to the requirements of code for installation of electrical equipment in explosive hazardous areas. If the field conductor is SBH type or other six core or eight core, the outer diameter is Φ Install cables with about 11.3mm rubber. During use and maintenance, it is strictly prohibited to power on and open the cover for maintenance and pry the flameproof surface in explosive places. At the same time, do not knock or scratch the flameproof surface during disassembly and assembly, and return to the original flameproof required state after maintenance.

The reducer of the actuator shall be lubricated after disassembly and repair. Generally, the low-speed motor shall not be disassembled, cleaned and lubricated. After assembly, check whether the valve position is consistent with the valve position opening indication.