The installation quality of the two position switching valve, as a key actuator in the fluid control system, directly affects the sealing performance, response speed, and operating life of the system. The scientific installation process should cover five core steps: selection and matching, location planning, mechanical assembly, sealing treatment, and functional verification. The following is a detailed operation guide.
1、 Accurate selection and pre inspection preparation
Before installation, it is necessary to strictly verify the valve parameters and operating requirements. Key confirmation of medium compatibility - corrosive fluids should be made of Hastelloy or fluorine lined materials, and high-temperature steam systems should be equipped with radiator type valve bodies. Check the type of actuator. Pneumatic diaphragm type is suitable for low-pressure scenarios, while electric piston type is more suitable for high-pressure differential conditions. During the unpacking inspection, it is necessary to verify the certificate of conformity, material report, and pressure rating identification, with special attention paid to the flexibility of valve disc opening and closing. The resistance should be evenly felt when manually turning the handwheel without any jamming.
2、 Reasonable positioning and pipeline layout
The installation location follows the principle of "easy to operate and maintain". For horizontal pipelines, it is recommended that the valve axis be parallel to the ground, while for vertical pipelines, the valve stem should be kept in a vertical position. The length of the front and rear straight pipe sections shall not be less than 5 times the pipe diameter to avoid vortex flow affecting the flow characteristics. For media containing particles, it is recommended to use side loading to prevent impurity deposition. Reserve sufficient maintenance space, with the handwheel operating surface at least 40cm away from the wall, and a 60cm safety passage around the electric head.
3、 Flange connection and sealing process
Flange docking is a critical process. Use a precision square ruler to calibrate the parallelism of the two flange surfaces, with a deviation not exceeding 0.5mm/m. Choose gaskets that match the medium, rubber gaskets can be used for water systems, and PTFE coated gaskets are recommended for oil media. The bolts are tightened three times in diagonal order, pre tightened and leveled twice, and the final torque reaches 80% of the design value. Pay special attention to the direction of the arrow on the valve body being consistent with the flow direction of the medium. Installing in the opposite direction may result in loose closure.
4、 Installation Specification for Execution Mechanism
When installing the pneumatic actuator, a filter pressure reducing valve combination device should be installed at the inlet, with a filtration accuracy of not less than 5 μ m. When adjusting the limit block, first manually fully open/close the valve disc, and then fine tune the screw to accurately trigger the travel switch. The electric actuator needs to check the motor direction, and observe whether the indicator board is synchronized with the actual action during the power on test run. The electromagnetic directional valve should be installed vertically with the coil facing upwards to prevent water accumulation.
5、 System debugging and protective measures
After installation, a pressure test should be conducted with a test pressure of 1.5 times the working pressure. If there is no visible leakage after holding the pressure for 15 minutes, it is considered qualified. Perform air tightness testing on pneumatic pipelines, apply soapy water to weld joints to check for leaks. Rinse the pipeline and remove foreign objects such as welding slag before putting it into operation. Outdoor installation requires the installation of protective covers, and in cold regions, a heat tracing belt should be provided. Establish a regular inspection system, focusing on checking the tightness of the stuffing box cover and the lubrication condition of the actuator.