How to install medium and high pressure valves?

Installing medium and high pressure valves is an important part of ensuring their normal operation and extending their service life. Due to the high working pressure involved in medium and high pressure valves, special attention needs to be paid during the installation process to ensure safe, stable and efficient operation.

1. Preparation before installation

1.1 Check the valve and its accessories
Model and specification: Make sure that the model and specification of the selected valve meet the design requirements and match the working pressure, temperature, medium, etc. of the system.
Sealing performance: Check whether the valve seals (such as O-rings, gaskets, etc.) are intact and ensure that there is no damage.
Component integrity: Check whether the components inside the valve (such as valve seats, valve cores, actuators, etc.) are intact and the valve can be opened and closed normally.
Clean the valve: The valve should be clean, especially the valve seat, sealing surface and other parts that are easily contaminated. Avoid welding slag, oil stains, and impurities from entering the valve.
1.2 Check the pipeline system
Pipeline cleaning: Make sure that the pipeline system in the installation area is free of impurities, oil stains, dust and welding slag. Prevent impurities from entering the valve by purging or cleaning the pipeline.
Pipeline connection: Check whether the flange, thread or welded joint of the pipeline meets the connection requirements of the valve, and ensure that the connection is intact and undamaged.
1.3 Check the working pressure and medium
Ensure that the rated pressure range of the valve is consistent with the working pressure of the system to avoid valve damage or leakage due to pressure overrun.
Ensure that the valve is suitable for the type and temperature range of the working medium, especially for high-pressure systems. The material selection must be adapted to high temperature or corrosive media.

2. Installation steps

2.1 Determine the installation position
Direction: The valve usually has a flow arrow marked on the valve body. When installing, ensure that the flow direction of the fluid is consistent with the direction indicated on the valve body.
Vertical or horizontal installation: The installation position of medium and high pressure valves needs to consider the working mode of the system. Generally, the valve can be installed horizontally or vertically, but it should be determined according to the specific working conditions and valve type.
Avoid excessive force: Avoid external mechanical loads when installing the valve to avoid damage to the valve due to vibration or imbalance.
2.2 Install the valve
Flange connection:
Use suitable gaskets (such as graphite gaskets, stainless steel gaskets, etc.) to ensure that the flange connection is well sealed.
When connecting the valve to the pipeline flange, ensure that the flange surface is flat to avoid sealing failure due to unevenness.
Use bolts to tighten evenly to avoid leakage caused by uneven force on the flange joint. Generally, tighten gradually in a diagonal manner to ensure uniform sealing.
Welding connection:
When welding, ensure that the welding temperature and welding quality meet the requirements. Avoid deformation of the valve structure due to excessive temperature or improper welding.
After welding, the weld should be inspected to ensure that there are no defects such as cracks, pores, and leaks in the welding.
Threaded connection:
For valves with threaded connections, ensure that the threads are not damaged and the sealing materials are properly selected (such as using thread sealing tape or sealant).
When threading, avoid over-tightening to prevent damage to the threads or excessive stress on the valve.
2.3 Check support and stability
Support structure: Ensure that the valve and pipeline are properly supported to avoid damage to the valve due to stress deformation or vibration of the pipeline during operation.
Expansion compensation: For high temperature and high pressure systems, considering the influence of thermal expansion, equipment such as expansion joints and compensators should be used to prevent valve deformation due to heat.
Anti-seismic bracket: When necessary, anti-seismic brackets can be installed to prevent the valve from being adversely affected by external vibration.
2.4 Connection between actuator and control system
Pneumatic actuator: For pneumatic control valves, connect the air source pipeline to ensure that the air source pressure is stable, and check whether the pneumatic valve actuator is correctly installed and debugged.
Electric actuator: For electric control valves, connect the power supply and signal control system, check whether the electrical connection is firm, and ensure that the electric actuator can work normally.
Signal access: Ensure that the signal input of the valve (such as current, pressure, temperature signal, etc.) matches the control system and debug it.

3. Inspection after installation

3.1 Sealing check
Air tightness check: After installation, check whether the valve sealing performance is good through gas or liquid test (for example, boost test, immersion test, etc.). If leakage is found, the cause should be immediately investigated and repaired.
Flange joint: Especially check the sealing of flange joints, threaded connections and welds to ensure that there is no leakage.
3.2 Pressure test
After installation, perform a system pressure test to confirm the reliability of the valve under working pressure.
Pressure test: gradually increase the medium pressure in the pipeline, observe the response of the valve and pipeline, and ensure that the valve can withstand the expected working pressure.
Temperature test: For high temperature working environment, temperature test is also required to ensure that the valve can withstand the system working temperature.
3.3 Operation test
Perform an operation test of the valve to confirm the flexibility and accuracy of the valve in the switch operation.
Check the working status of the actuator to ensure that the valve responds to the control signal and works as expected.

4. Maintenance after installation

After installing the medium and high pressure valve, perform the following maintenance regularly:
Regularly check the valve: regularly check the sealing, operating status and appearance of the valve to ensure that there are no problems such as leakage, wear or corrosion.
Check the actuator and control system: regularly check the working status of the actuator and electrical/pneumatic control system to ensure that the valve responds normally.
Replace the seal: As the service time increases, the seal of the valve may age or be damaged and needs to be replaced in time.

Summary
The installation process of the medium and high pressure valve needs to follow strict technical requirements and operating specifications to ensure that the valve is tightly connected to the pipeline system, well sealed, and can operate safely under high pressure. During the installation process, key steps include checking the valve and piping system, correctly connecting the valve, and conducting tightness and pressure tests. At the same time, strict operation and maintenance inspections should be carried out after installation to ensure that the valve works stably for a long time.