Brief Introduction to the Testing Principle of Vacuum Degree Instruments

Vacuum degree instrument testingPrinciple description:

Pull apart the two contacts of the arc extinguishing chamber by a certain distance and apply pulse high voltage; Place the arc extinguishing chamber inside the spiral coil or place the new electromagnetic coil outside the arc extinguishing chamber, apply magnetic field voltage to the coil, and generate a pulse magnetic field synchronized with high voltage inside the arc extinguishing chamber. Under the action of pulsed magnetic field and strong electric field, electrons in the arc extinguishing chamber undergo spiral motion and collide with residual gas molecules for ionization. The resulting ion current is proportional to the density of the residual gas (i.e. vacuum degree value). For different types of vacuum tubes (tube types), due to their different structures, the magnitude of ion current varies under the same contact distance, vacuum degree, electric and magnetic fields. The corresponding relationship curve between the vacuum degree of various tube types and the ion power source can be calibrated through experiments. After measuring the ion current, the vacuum degree of the tube type can be obtained by querying the ion current vacuum degree curve of the tube type. When testing the vacuum degree of the arc extinguishing chamber using conventional magnetron discharge method, in order to improve the testing sensitivity, the arc extinguishing chamber needs to be removed from the circuit breaker and placed inside the spiral tube coil. In this way, when reinstalling the arc extinguishing chamber onto the circuit breaker device, it is necessary to readjust the mechanical parameters, which requires a large amount of work and professional expertise. The use of a new type of magnetic coil can surround the arc extinguishing chamber from the side, so there is no need to disassemble the arc extinguishing chamber. Simultaneously using a single-chip microcomputer for synchronous control and data acquisition processing has improved the sensitivity of on-site testing of the vacuum degree in the arc extinguishing chamber.