Development and Application of Helium Mass Spectrometer Leak Detector

In the era of continuous development of science and technology, helium mass spectrometry and its application technology are also continuously developing and improving. This is mainly determined by two factors: On the one hand, the leak detection application technology constantly puts forward new requirements on the leak detector, forcing the instrument to update itself; on the other hand, the leak detection technology also supplements the existing leak detection anytime and anywhere. There are some deficiencies in the application process of the instrument, so the relationship between the two is complementary and mutually reinforcing.
1. The progress of Helium Mass Spectrometer Leak Detector After nearly half a century of efforts, today's Helium Mass Spectrometer leak detector has bid farewell to the situation in the early 1940s.
Focus on the following aspects:
(1) Portable: Small portable leak detectors recently introduced by various countries are not only highly sensitive but also portable, providing greater convenience for field operations and high-altitude operations.
(2) Leak detection under high pressure: The leak detection pressure can be as high as several hundred pascals, which is useful for detecting large systems and large leaky workpieces.
(3) High degree of automation: automatic calibration peaks, automatic adjustment of zero, automatic range conversion, automatic data processing, external printer. The whole machine is controlled by a microcomputer, and the menu selection function can complete a full inspection leak process with one button.
(4) Dry inspection with no oil: The leak detectors produced in some countries can use dry pumps to achieve the effect of no oil vapor, providing favorable conditions for leak detection of semiconductor devices such as oil-free systems and chips. .
(5) Wide range of leak detection: Today's production of four-pole leak detectors has a wide range of quality and can detect not only helium but also other gases.
The molecular pump exhaust system replaces the diffusion pump exhaust system, which not only solves the problem of oil vapor contamination of the mass spectrometer, but also makes a great contribution to rapid startup of the instrument and rapid shutdown. In order to adapt to changes in pressure at the leak detection port and the different sensitivity requirements, the molecular pump generally adopts multi-stage construction and several different rotational speeds.
For example, this can be achieved by changing the speed of the molecular pump and increasing the leak detection sensitivity.
In addition, the reverse diffusion leak detection method achieves leak detection under high pressure and also provides good conditions for positive pressure sniffer leak detection.
2. Application of Helium Mass Spectrometer Leak Detector The application of Helium Mass Spectrometer Leak Detector has moved from the Academy of Sciences, universities and colleges, laboratories, and a few scientific research institutions to industrial and mining enterprises, and even township and village enterprises and individual enterprises. It can be said that the application field is extremely broad.
(1) Aerospace high-tech industries 1) For example, rocket engines and attitude engines used to be used as pressure detector soapy water leak detectors, and now they have improved the use of helium-mass spectrometer leak detectors to detect leaks. The use of positive pressure sniffer guns combined with helium masks Leak detection sensitivity greatly improved, thus ensuring the quality of the engine. Rocket rocket leak detection using a combination of positive pressure sniffer, helium mask method, cumulative set of several methods. Due to the application of leak detection technology, the sensitivity of the leak detection is improved, which compensates for the low sensitivity of the instrument when the leak detection method is used.
2) The equipment of the KM6 space ring mold device is huge. The main vacuum chamber has a diameter of 12m and a height of 22m. There are auxiliary vacuum chambers and manned cabins. With a capacity of 3500m3, many sub-systems, and complex structures, the interface welds add up to several kilometers long. The helium mass spectrometer leak detector negative pressure leak detection, each weld is sealed by the leak detection box, together with the help of exhaust gas After the system draws a vacuum in the box, it is filled with a certain pressure and helium gas is turned off, the pre-pumping valve is closed, and the leak check valve is opened. Due to the high concentration of antimony in the box, there is a certain pressure on the leak detector, which effectively improves the sensitivity of the leak detection.
3) In the aerospace industry, helium mass spectrometer leak detectors and leak detection techniques are widely used in satellites, valves, electronic components, and sensors.
(2) The SF6 high-voltage switch and zinc oxide surge arrester in the power industry are important components of power plants and field power transmission and transformation. They often cause large-scale or partial power outages due to leakage, affect industrial production, and hinder people's normal life. The resulting economic losses are sometimes difficult to assess.
1) The high-voltage switch is aluminum casting in the box, which is easy to have trachoma, and the leakage hole structure is complex and difficult to clean. A leak detection box or a dome cover method is generally adopted, that is, the part to be inspected is evacuated, and then the lid is filled with helium gas, and the total leak rate is determined after waiting for a certain period of time. Due to the small amount of helium, the detection sensitivity is high.
2) Zinc Oxide arresters are based on voltage requirements, using different cross-sectional areas, different thicknesses and different amounts of zinc oxide tablets, installed in a porcelain sleeve, sealed after filling with nitrogen gas. Its working principle is that in the event of a lightning strike in the high-voltage output, the resistance of the zinc oxide sheet becomes smaller, a large current is shorted to ground, and the transmission line is protected. If there is no pressure difference inside and outside the leak, external humid gas may enter, and the characteristics of the zinc oxide film are destroyed, causing explosion.
3) In the power industry, leak detection of power plants, high-voltage transformers, high-voltage capacitors, high-voltage switch tubes, and other components are also corresponding to the use of helium-mass spectrometer leak detectors, which use different methods for leak detection.
(3) Microwave emission tubes, tubes, transistors, integrated circuits, sealed relays, various types of sensors, cardiac pacemakers in the electronics industry.
(4) vacuum industry, instruments, instrumentation industry pipelines, joints, valves, bellows, various vacuum pumps, various types of exhaust units, electron microscope, mass spectrometer, electron beam ion velocity exposure machine, laser axis separator, high energy accelerator, medical Accelerator, irradiation accelerator, coating machine, film vacuum gauge.
(5) Nuclear industry uranium separation devices, storage devices, nuclear power generation devices.
(6) Refrigeration industry Refrigerators, air conditioners, lithium bromide refrigeration units, automotive air conditioners, evaporators, condensers, decelerators, and cryogenic storage tanks.
(7) Stainless steel vacuum insulation cups, bottles, pots, lunch boxes, etc.
(8) Other According to a related Japanese article, in the Japanese automobile manufacturing industry, there are more than 30 kinds of parts and components that are leak-checked using a helium mass spectrometer leak detector to solve the problem of sealing. These include hydraulic systems, brake systems, steering systems, suspension systems, and even car wheels.
There are still many areas for leak detection that need to be explored, but due to the constraints of ideas and funding, and many other reasons, there are still many ancient and relatively backward methods to deal with leakage in many areas. Product pass rate and production efficiency are low. In a sense, this type of work restricts the development of productivity. Therefore, for professional vacuum technicians, especially those engaged in the development of vacuum equipment and the production of Helium mass spectrometer leak detectors, further efforts should be made in the application and promotion of Helium Mass Spectrometer leak detectors, in order to promote the development of vacuum technology in China. .