Valve positioner is an important accessory in pneumatic valve to regulate flow. It is usually used with pneumatic actuator to control the opening of valve by receiving 4-20mA signal from controller or control system, so as to control the process parameters of pipeline media accurately. Valve positioner and pneumatic actuator are matched, and then connected with various automatic control units or valves. After debugging and installation, they are combined into pneumatic control valves for various industrial automation process control fields. Valve positioner can be divided into pneumatic valve positioner, electric valve positioner and intelligent valve positioner according to its structure.
Installation process of valve positioner
1. Generally, the height (H) of the axis of pneumatic actuator can be divided into 20, 30 and 50 mm. After confirming the height of the actuator shaft, assemble the bracket according to the picture below.
2. Connect the bracket to the bracket of the actuator with a hexagonal head bolt. The diameter of the hole connected to the bracket of the actuator is 6mm, so the appropriate screw should be selected. And in order to prevent the screw from being loosened by vibration and other factors, please use spring washer or other methods to install. The installation direction of the bracket is different according to the use conditions, but it is generally recommended to install the bracket in the same direction as the actuator piping and valve positioner piping as shown in the following figure.
3. Align the rotation position of the actuator axis to the starting position, that is, 0% of the opening. When the actuator is a single-acting cylinder using springs, the cylinder shaft always returns to the starting point if the air pressure is not input, so it is easy to confirm. When double-acting cylinder, please refer to the cylinder manual to confirm whether it is clockwise or counterclockwise rotation, or to determine the direction of cylinder axis rotation when air pressure is input.
4. After setting the fork rod, tighten the fixed screw under the fork rod clockwise. The valve positioner is mounted on the bracket.
5. Fixed with hexagonal bolts and washers
