The vacuum system of vacuum heat treatment furnace must meet the following three basic requirements.
1. The vacuum heat treatment furnace can be rapidly pumped to the required vacuum limit.
2. The gas continuously released from the treated workpiece and the furnace structure, as well as the gas infiltrated into the furnace due to vacuum leakage, should be discharged in time.
3. The operation, installation and maintenance of the system are simple, and the whole system covers a small area.
Vacuum heat treatment is a new type of heat treatment technology which combines vacuum technology with heat treatment technology. Vacuum environment of vacuum heat treatment refers to atmospheric environment below one atmosphere pressure, including low vacuum, medium vacuum, high vacuum and ultra-high vacuum. Vacuum heat treatment actually belongs to atmosphere-controlled heat treatment. Vacuum heat treatment means that all and part of the heat treatment process is carried out in vacuum, and the quality of heat treatment is greatly improved. Compared with conventional heat treatment, vacuum heat treatment can achieve no oxidation, no decarbonization, no carburization, removal of phosphorus chips on the surface of workpiece, degreasing and degassing, so as to achieve the effect of surface brightness and purification.
Vacuum system of vacuum heat treatment furnace is generally composed of vacuum pump, vacuum valve, vacuum measuring instrument, cold trap, pipeline and so on. Here are some common vacuum systems.
1. Low vacuum system is suitable for vacuum heat treatment furnaces with vacuum degree of 2-1333Pa. In case of pumping well type vacuum furnaces, this system is mostly used.
2. Vacuum system with mechanical booster pump is suitable for vacuum heat treatment furnace with vacuum degree of 1.33-3*10 in negative 1Pa range. Vacuum quenching furnace widely uses this system.
3. High vacuum systems and high vacuum systems with booster pumps are suitable for vacuum heat treatment furnaces with vacuum of 1.3 x 10 in the range of negative-2 to 6.6 x 10. Vacuum annealing furnaces and vacuum brazing furnaces mostly use this system.
Three Basic Requirements for Vacuum System of Vacuum Heat Treatment Furnace
According to the technical conditions of vacuum heat treatment furnace and the required vacuum degree, the suitable vacuum pump is selected. Then according to the type and specifications of vacuum pumps, the corresponding vacuum valves, vacuum pipes and so on are selected to form the required vacuum system. Generally, the pumped volume has a certain relationship with the pumping speed of the vacuum pump. When the volume of the vacuum heat treatment furnace is determined, the corresponding pumping rate can be found out, and then the vacuum pump can be selected.