Baorui pvd equipment introduces you to the commonly used vacuum leak detection method
1. Helium mass spectrometry leak detection
This technology is an indispensable technology in the field of vacuum leak detection. Due to its high efficiency, easy to operate, sensitive instrument, high precision, and low resistance to other gases, it has been widely used in leak detection. The helium mass spectrometer leak detector is a gas tightness detecting instrument made of helium gas as a leak gas according to the principle of mass spectrometry. It consists of an ion source, an analyzer, a collector, a mass spectrometer chamber composed of a cold cathode ionization gauge, an extraction system, and an electrical part.
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The electrons emitted from the filament in the mass spectrometer oscillate back and forth indoors, and collide with the indoor gas and the helium gas entering the chamber through the leak hole to ionize into positive ions. These helium ions enter the magnetic field under the action of the accelerating electric field. Due to the Lorentz force acting to deflect, forming a circular arc orbit, changing the accelerating voltage allows different masses of ions to be detected by the magnetic field and the receiving slit reaching the receiving pole. The sneezing method and the suction method are the two most commonly used methods for detecting leaks in a helium mass spectrometer leak detector.
2. Vacuum seal detection method
The vacuum mud is sealed one by one for suspicious leaks. Pay attention to the change of the vacuum degree. If the vacuum is applied to the vacuum seal, the vacuum is improved quickly, and the removal is obviously reduced, indicating that this is a leak point. This method is used less in practical applications.
3. Vacuum gauge leak detection method
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Some vacuum gauge readings are related to the type of gas, such as thermocouples, ionization gauges.Selecting a suitable gas or liquid as the leaking material, these vacuum gauges become detectors. Generally, there are vacuum gauges on the coating machine, which is convenient to use and is also a commonly used leak detection method. The leaking substances used in the thermocouple meter are slow, and the thermocouples such as carbon dioxide, butane, and alcohol are slow to react, and the observation is very careful. The leaking substances used in the ionization meter are helium, argon, alcohol, and the like.
4. High frequency spark leak detection
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This method is only suitable for glass vacuum systems. The system is first evacuated, and the spark end of the high-frequency spark leak detector moves along the surface of the glass, and the spark is concentrated into bundles to form a bright spot.