Detailed Procedure for Valve Pressure Testing

 
Valve pressure testing is a critical step to ensure the safety and reliability of valves during operation. The primary purpose of pressure testing is to verify the strength and sealing performance of valves, ensuring they meet design and manufacturing standards. As essential components of fluid control systems, valve performance directly impacts the overall safety and stability of the entire system. Therefore, a rigorous pressure testing process and detailed inspection standards are crucial for quality assurance.
 

Purpose and Importance of Pressure Testing

 
The core objective of valve pressure testing is to assess the valve's ability to withstand specified pressures, ensuring that it will not leak or break during actual use. The compliance of the pressure testing process directly affects the safety of the valve, especially in high-pressure and high-temperature environments. Effective pressure testing can uncover potential manufacturing defects, material issues, or design flaws, allowing timely corrective measures before the valve is put into operation, thus avoiding safety hazards and economic losses.

Preparations Before Pressure Testing

 
Before conducting valve pressure testing, the following preparations are necessary.

1. Selecting Appropriate Testing Equipment

 
Ensure that the testing equipment complies with the specifications and requirements of the valve, including pressure gauges, pumps, connecting pipes, and safety valves. Testing equipment should be regularly calibrated to ensure measurement accuracy.

2. Cleaning the Valve

 
Remove dirt, residues, and impurities from the valve's interior to guarantee accurate testing. Special attention should be given to cleaning the valve sealing surfaces to avoid any substances that may lead to sealing failure.

3. Inspecting Valve Condition

 
Confirm that all components of the valve (such as the valve body, bonnet, and sealing surfaces) are free from damage. Special care should be taken with the quality of any repaired areas for refurbished valves.

4. Preparing the Testing Environment

 
Ensure that the testing area is well-ventilated and that the pressure testing equipment and valve are set up on a stable, level surface to avoid environmental factors affecting the test results.

Basic Pressure Testing Procedure

 
The basic procedure for pressure testing includes the following steps.
 
Installing the Valve: Mount the valve to be tested on the pressure testing equipment, ensuring it is oriented for easy inspection. Avoid positioning the valve in hard-to-observe locations.
Connecting the Testing Equipment: Connect the valve to the pressure source via piping, ensuring a tight connection without leaks.
Gradually Increasing Pressure: During testing, the pressure should be increased gradually to avoid sudden or sharp pressure spikes. Generally, the rate of pressure increase should not exceed the specified pressure increment per minute.
Monitoring Pressure Changes: Use a pressure gauge to monitor the test pressure, ensuring it remains stable within the specified range. Record the pressure variation process for subsequent analysis.

Testing Requirements and Precautions

 
During the pressure testing process, the following requirements and precautions should be observed.

1. Strength Test Requirements

 
During the pressure test, valves must not exhibit sweating or leakage. Typically, strength testing is not performed unless the valve body or bonnet has been repaired or shows signs of corrosion damage. For safety valves, their set pressure and reseat pressure, along with other tests, should comply with their specifications and relevant regulations.

2. Sealing Test

 
Valves usually undergo a single sealing test, but critical valves such as safety valves and high-pressure valves should be tested twice. During testing, minor leakage is permissible for low-pressure and large-diameter valves, but strict adherence to regulations is essential. Especially during the sealing test, ensure that the valve closure force does not exceed what a person can exert normally, avoiding the use of levers or other tools to apply extra force.

3. Testing Duration

 
The duration for strength and sealing tests is typically 2-3 minutes, with important valves requiring a duration of 5 minutes. Testing time for small-diameter valves may be shortened, while large-diameter valves may require longer testing times.

4. Permissible Pressure Increase Rate

 
Pressure should be increased slowly to prevent shocks and impacts during testing, ensuring stability at the valve and its connections.

Post-Testing Inspection and Record Keeping

 
After pressure testing, the following inspections and records are required.

1. Observing for Leaks

 
Check all parts of the valve to confirm whether any leaks are present. If leaks are detected, the pressure test should be stopped immediately, and repairs should be conducted.

2. Removing Accumulated Water

 
Timely removal of any accumulated water from the valve interior and cleaning of the valve surface are necessary to prevent corrosion and damage.

3. Recording Test Results

 
Document all data from the pressure testing process, including pressure values, testing duration, and leakage conditions, creating a complete test record for future reference and validation.

4. Subsequent Processing

Valves that have undergone pressure testing should receive follow-up maintenance to ensure continued good working conditions during use.

Conclusion

 
Valve pressure testing is a vital step in ensuring the safe and reliable operation of valves. By following standardized testing procedures and stringent inspection standards, it is possible to effectively prevent leaks or other failures during actual application. Therefore, manufacturers and users should prioritize valve pressure testing to ensure that every valve undergoes rigorous testing, thereby safeguarding industrial production, personal safety, and the stability and efficiency of the entire fluid control system.