When installing a pneumatic control valve, you need to pay attention to the following key steps and points to ensure that the control valve can operate normally and meet the process requirements:
1. Preparation before installation
(1).Environmental inspection: Ensure that the installation environment is clean, dry, free of dust and debris, the ambient temperature should be between -25℃ and 55℃ (or -30℃ to 60℃), and the relative humidity does not exceed 95%.
(2)Pipeline cleaning: Before installation, foreign matter in the pipeline, such as dirt, welding slag, etc., must be thoroughly removed to prevent debris from getting stuck and damaging the throttling parts.
(3)Inspect the valve: Check whether the appearance of the pneumatic control valve is damaged, whether the sealing surface is intact, and whether there is no debris accumulation in the stuffing box.
2. Installation position and direction
(1)Position selection: The pneumatic control valve should be installed in a position that is convenient for maintenance and repair. It is required to have a certain height from the ground, and a certain space should be left above and below the valve for disassembly and repair. For control valves equipped with pneumatic valve positioners and handwheels, it must be easy to operate, observe and adjust.
(2)Direction determination: The regulating valve should be installed vertically on the horizontal pipeline, perpendicular to the pipeline up and down. When horizontal and inclined installation is required in special circumstances, support is generally required. At the same time, the direction of the arrow on the valve body or flange must point to the direction of the medium.
3. Connection and fixation
(1)Connection method: Select the appropriate connection method according to whether the diameter of the regulating valve is consistent with the diameter of the process pipeline. When the two are inconsistent, a reducer should be used for connection. When installing a small-diameter regulating valve, threaded connection can be used. When connecting the flange, if the temperature exceeds 350℃, high-temperature resistant bolt materials must be used.
(2)Fixed installation: Use a level to calibrate the level to ensure that the valve is installed smoothly. The bolt tightening force of each component should be uniform and appropriate, and the end of the connecting flange should be tightened with a gasket.
4. Accessory installation
(1)Bypass pipeline: In order to ensure that the regulating valve and the regulating system do not affect production and safety accidents when they fail, bypass and bypass valves are generally required. The bypass valve cannot be installed directly above the regulating valve to prevent the corrosive medium in the bypass valve from leaking to the regulating valve.
(2)Other accessories: According to the process requirements, accessories such as the shower valve may also need to be installed.
5. Debugging and inspection
(1)Air tightness check: After connecting the air source, check the air tightness to ensure that there is no leakage at the connection.
(2)Functional test: Connect the fluid medium, observe the opening and closing of the valve under the action of the medium, ensure that there is no leakage, and adjust the air source pressure so that the opening and closing speed of the valve meets the requirements.
(3)Regular inspection: Regularly check whether there is leakage at the connection, clean the valve surface and the surrounding environment, and prevent dust or debris from entering the valve. At the same time, check whether the seals and transmission devices of the valve are worn or aged, and replace them if necessary.
6. Precautions
(1)Avoid vibration: Try to avoid installing the pneumatic control valve in places with vibration sources, otherwise necessary anti-vibration reinforcement measures should be taken.
(2)Straight pipe section requirements: There should be a straight pipe section before and after the control valve, and the length should not be less than 10 times the pipe diameter (10D) to avoid the straight pipe being too short and affecting the flow characteristics.
(3)Operation safety: During the installation and commissioning process, relevant safety operating procedures should be followed to ensure the safety of personnel and equipment.
