Leak Detection of Vacuum Furnace
Operation rules for operation and maintenance of vacuum furnaces, establishment of operation records and repair files of vacuum furnaces, statistics of accumulated working hours, strengthening daily maintenance of vacuum furnaces, mastering the changing trend of equipment technical status, early detection of failure and damage, avoiding emergency repair of vacuum furnaces, and preparation of repair of vacuum furnaces in advance according to the working load and operation status of vacuum furnaces. Operation and maintenance of vacuum furnace with spare parts. For example, the service life of vacuum furnace heating elements is related to many factors, such as working temperature, product medium in vacuum furnace, product quantity and operation. Under the condition of 24 hours processing and production every day, the replacement of vacuum furnace heating elements and heat shield takes place every two or three years, which depends on the type of brazing work and the number of times used. Vacuum furnaces usually have more leakage failures in spring and autumn. Vacuum furnaces that have been idle for a long time are easy to occur when they are only used for a second time. Vacuum leak detection must be carried out at this time. Vacuum leak detection usually takes the rate of pressure rise once a month (closing all vacuum valves at room temperature, stopping the operation of vacuum system, reading a number after one minute, reading a number after one hour, the difference between the two numbers is the value of pressure rise rate). To grasp the trend of equipment leak change, such as vacuum equipment shutdown continuously for one week, running empty once (drying oven).
In vacuum system leak detection, except for temporary emergency maintenance with vacuum mud plugging, helium mass spectrometer leak detector can be used for vacuum leak detection by helium mass spectrometer. If there is no helium mass spectrometer leak detector, acetone or ether can be injected into suspected leak point by medical needle tube to observe whether the reading of vacuum meter has changed. It can also make blind plates with holes inserted in vacuum silicon tubes, block vacuum pipelines in segments and detect leakage. After finding the leak point for maintenance (generally the seal ring aging is more), check the sliding valve pump, Roots pump, maintenance pump and diffusion pump oil of vacuum furnace regularly. If the oil is found to be emulsified by water and the vacuum drops, the above four pumps must be replaced, and the oil level and quality should be checked once a week. The coke deposited in oil diffusion pump of diffusion pump can be cleaned by chemical pickling.