The reasons of the poor vacuum degree in vacuum furnace

The vacuum furnace cannot reach the vacuum degree: it may be that the pumping capacity of the vacuum unit is not enough, it may be that the leakage rate is too high, or both.

After evacuating the vacuum chamber to a certain vacuum state, close the vacuum valve. If the vacuum count rises quickly, the vacuum chamber leaks in most cases.

At this time, the leak should be detected first and dealt with properly. If the vacuum count value rises slowly, it may be that the vacuum unit has insufficient pumping capacity.

The focus of the vacuum quenching furnace is to find the leakage of the vacuum pump and valve, or the vacuum pump oil is contaminated or oxidized, or the foreline pipeline is not well sealed, the pump oil is insufficient, or the pump oil is emulsified, and the shaft seal leaks.
At this time, replace the vacuum pump oil or directly replace the vacuum pump. If the vacuum of the equipment drops rapidly in a short time.

Generally, it is caused by the aging, scratches, and oxide scale falling off of the dynamic seals such as the furnace door, vacuum valve, and middle partition of the vacuum furnace. The seals can be cleaned and replaced, and the valve can be manually opened for maintenance.
If there is no problem, check the position of the interface between the vacuum chamber and the outside world, such as connecting flanges, water-cooled electrodes, pipes and vacuum tubes, etc. Sometimes the acetone leak detection method can be used to observe the vacuum change and carefully find the leaks.

If there is no leak in the vacuum furnace, it is necessary to disassemble and re-install all suspected gas leaks, or to process a solid flange to block the test.

Read More : Vacuum Furnace