There are many leakage detection methods for vacuum box helium leak detection equipment. According to the measurement purpose of the detection components, one is the leakage point, and the other is the leakage rate. In actual detection, a reasonable method should be selected according to the detection purpose, and various detection methods should be flexibly applied according to the specific situation of the detection equipment. Measurement of leakage type. Identifying the type of leakage point is to determine the specific leakage point and location of the leakage hole of the component to be inspected, which is commonly found in large components such as satellites, missile bodies, warheads, gas pipes, gas tanks, oil tanks, boilers, etc. 1、 The helium method is a commonly used method for detecting small components, connecting the tested equipment and devices, evacuating the vacuum, and spraying it out with a spray gun in areas where the tested equipment has leaks (such as sealed joints, welding, etc.). If a leak is found in a certain part of the tested equipment, helium will be immediately sucked into the vacuum system, diffused into the mass spectrometry chamber, and sprayed out immediately. This method uses an inert gas, which will automatically rise after spraying and must be sprayed correctly at the location of the leak. The spraying must be from high to low. Due to the fact that helium leaks from near to far, it may leak into the same space and leak into the same area. Space. Large parts use vacuum pre suction mechanical pumps to pre suction vacuum, which can improve leak detection efficiency and shorten leak detection time. The spray method is used for leak detection in small containers with complex structures, multiple sealing ports and welds, and squeezing. Due to the rapid diffusion of helium after spraying, it is difficult to correctly detect the location of the leak. Different angles of helium spraying should be used to carefully observe the difference in reaction time, and the discovered leaks should be temporarily sealed with vacuum sealing mud for easy detection. The helium absorption method is mainly used to detect some large sealed containers. For example, for projectiles, warheads, gas cylinders, oil tanks, etc., the container is first evacuated and then filled with helium (low concentration helium can be used to save helium usage). A rubber tube is connected to the inlet of the helium mass spectrometer leak detector, and a small diameter capillary tube is at the front end of the rubber tube. The capillary tube can be moved to determine the type of leak rate at the welded and sealed joints on the outer wall of the detector filled with helium. It mainly detects components with high airtightness requirements such as spacecraft, liquid fuel storage, satellites, and electronic components. This method can only detect the leakage rate of the specimen and cannot determine the leakage points and quantity of the specimen. Helium filling method, also known as helium filling method, refers to connecting a vacuum pump and a helium tank to a closed gas chamber, placing the inspected component into the gas chamber, and starting to close the helium tank valve. The pump first evacuates the gas chamber, then closes the vacuum pump valve, opens the helium tank valve, and fills the gas supply chamber with helium, allowing it to stand for a period of time. On small devices, surrounded by helium gas, if there is a leak, the helium gas will slowly fill the interior of the device. Secondly, open the air chamber, remove the detection device, and blow the helium that may be adsorbed on the external surface with compressed air. Install these components one by one in the container, receive the inlet flange of the detector, remove the container, open the throttle valve, and allow helium entering the detection component to be discharged through the detection hole again. The detector responds to the leakage rate. The leak detection of the entire artificial satellite adopts this method. The artificial satellite is placed in a large annular chamber, and the vacuum system of the annular equipment is used to evacuate the annular space. Firstly, an auxiliary pump is used for rough and pre extraction. During leak detection, a mechanical pump is first used to evacuate the artificial satellite and the inflation pipeline, and helium is filled into the artificial satellite at the same pressure as the working pressure of the artificial satellite. Then, a standard leak calibration instrument is used to open the helium mass spectrometer leak detector. The second method is the bell jar method, which connects the helium mass spectrometer leak detector and the test piece with a vacuum hose. The test piece is covered with a closed container and filled with helium. The leak detector begins leak detection. When there is a leak point on the test piece, the instrument can display the leak rate. This method can measure the leak rate of missile liquid storage tanks. Cover the container with plastic film and perform rough and pre sampling on it.