- Pressure decay method
- Prepare equipment: a vacuum pump, pressure sensor, vacuum test chamber, and related connecting pipes and valves are required.
- Install valve: Install the vacuum check valve at a suitable position in the vacuum test chamber to ensure that it is firmly installed and well sealed.
- Evacuate: Start the vacuum pump and evacuate the test chamber to reduce the pressure in the chamber to the set vacuum degree, which can generally be evacuated to below 10⁻²Pa.
- Monitor pressure: Close the vacuum pump and related valves to isolate the test chamber from the outside world, and then use the pressure sensor to monitor the pressure changes in the chamber in real time. If the valve is well sealed, the pressure in the chamber should remain stable; if there is a leak, the pressure will gradually rise.
- Data analysis: Judge the sealing performance of the valve based on the rate and amplitude of pressure change. The slower the pressure rise rate, the better the sealing effect; conversely, the worse the sealing effect.
- Helium mass spectrometer leak detection method
- Prepare equipment: helium mass spectrometer leak detector, vacuum pump, helium source, and connecting pipes, etc.
- Vacuuming: Place the vacuum check valve in the vacuum chamber and use a vacuum pump to pump it to the specified vacuum degree, generally below 10⁻⁴Pa.
- Apply helium: Apply helium outside the tested part of the valve. Helium molecules have a small molecular weight and can enter the inside of the valve through a tiny leakage channel.
- Detect helium: The helium mass spectrometer leak detector will detect the helium entering the valve and display the corresponding signal. According to the intensity and change of the signal, determine whether the valve is leaking and the severity of the leak.
- Bubble method
- Prepare equipment: transparent container, water, vacuum pump, connecting pipes, etc.
- Install the valve: Install the vacuum check valve at one end of the transparent container to ensure that the installation is well sealed.
- Vacuuming: Use a vacuum pump to extract the air in the container to form a vacuum state in the container.
- Observe bubbles: During the vacuuming process, observe whether bubbles are generated on the water surface in the container. If bubbles are generated, it means that the valve is leaking; the faster the bubbles are generated, the more serious the leak.
- Applying method
- Prepare materials: soapy water, detergent water or other viscous and foaming liquids.
- Apply liquid: Apply soapy water or detergent water to the sealing parts of the vacuum check valve, such as the connection between the valve cover and the valve body, the contact between the valve stem and the packing, etc.
- Observe bubbles: Observe whether bubbles are generated in the area where the liquid is applied. If bubbles are generated, it means that there is a leak in that area; the faster the bubbles are generated, the more serious the leak.
