Vacuum Furnace Preventive Maintenance Strategies

Daily maintenance of vacuum furnace:
(1) Operators should be familiar with various instruments, pumps, and various parts of the equipment. Read and understand various manuals.
(2) The cooling water pressure should be maintained between 0.1 and 0.2 MPa, and the outlet water temperature should be ≤45℃.
(3) The compressed air pressure should be between 0.4 and 0.5 MPa.
(4) Before starting each furnace, check the capacity of the protective gas cylinder to avoid insufficient gas filling and replace the cylinder.
(5) If there is any abnormality after starting the machine, it should be eliminated immediately or the machine should be shut down to find the cause.
(6) Check the return water volume of each part frequently, and ensure that each part has sufficient cooling water during operation.
(7) When the equipment is out of use, the gas in the furnace should be evacuated. If it is not used for a long time, it should be filled with protective gas and the circulating water in the water cooling jacket of the equipment should be drained.
(8) Mechanical pumps and Roots pumps should be regularly changed and refueled. The oil cup of the Roots pump should always have oil. Be sure to drain the waste oil when changing the oil. The mechanical pump needs to open the gas ballast valve regularly. The slide valve pump needs to be drained regularly.
(9) When changing the oil of the diffusion pump, if the internal diffusion pump oil is oxidized, the oxide layer on the inner wall of the diffusion pump should be polished and cleaned before replacing the new oil.
(10) The purity of the protective gas filled in should not be less than 99.9996%.
(11) This equipment is not allowed to use flammable, explosive and corrosive gases as protective atmosphere.
(12) The surface of the equipment and the instrument should be kept clean. When wiping the inner wall of the furnace body, it is not allowed to use a rag with moisture or non-vacuum oil.
(13) The oil-water separator on the pneumatic three-way joint of the pneumatic system should be drained frequently, and the oil mist should be filled with vacuum diffusion pump oil.
(14) The overall voltage of the equipment should be guaranteed to be within the range of 350-420 V. The three phases should be balanced. (15) Vacuum gauges, electric contact pressure gauges, thermocouples, etc. should be frequently coated with diffusion pump oil to form an oil film between them and the seat to prevent air leakage. The above parts and flange joints are not allowed to be sealed with vacuum mud for a long time. (16) The bolts of the electrodes and other parts should be checked regularly. If they are found to be loose, tighten them in time. (17) When the equipment is working, pay attention to the display of each instrument and the sound of each pump so as to find abnormalities and problems in time. (18) The operating environment of the equipment should be below 85% relative humidity and the temperature should be between 10 and 40℃. When dismantling and repairing the equipment, the parts should not be hit with a heavy hammer, and the sealing surface and sealing groove should not be scratched. (19) When the vacuum brazing furnace is working, the operator shall not leave the post for a long time.

Maintenance of vacuum furnace:
① The pump room environment should always be kept clean and dry.② The condition of the lubricating oil in each part should be paid attention to at all times. If it is found to be insufficient, it should be replenished in time. If it is found to be unclean, it should be replaced in time, and attention should be paid to ensuring the seal when the screw plug is screwed back in. The working pressure difference of the pump should be controlled within the pressure difference range allowed by the bypass valve, otherwise the motor is easy to burn out. ③ The components cannot be hit with a heavy hammer during disassembly and repair.④  Avoid bruising and scratching of the removed parts. Pay special attention to the flatness and smoothness of the sealing surface, otherwise it will cause air leakage after reassembly, and the pump cannot restore its original performance. ⑤ The removed parts should be cleaned with gasoline, carbon tetrachloride or ether, and can only be assembled after drying. ⑥ During assembly, pay attention to the gap between the two ends of the rotor and the left and right side covers, and the gap between the rotor and the rotor, and the gap between the rotor and the pump body should be adjusted according to the specified requirements. ⑦ The joint surface between the left and right side covers of the pump body is sealed with ordinary vacuum grease (i.e. room temperature vulcanized silicone rubber).

VACUUM FURNACE