The workpiece must be cleaned before being treated in the vacuum furnace

The workpiece must be cleaned before being treated in the vacuum furnace

As there are many types and types of vacuum furnaces, the maintenance and overhaul items are different. The maintenance and inspection contents shall be divided into items for each furnace, every day, every month, every half a year and every year according to the furnace technical documents and actual needs.

Routine maintenance

1. For the air pump with gas ballast function, check it every day before the furnace is opened and open it for 30min as required to remove the water in the pump oil.

2. Frequently check the pressure of cooling water, compressed air, hydraulic system and the flow of cooling water.

3. Check the rubber seal and flange surface of the furnace door before closing the guard door. There shall be no sand and sundries. Wipe the rubber seal ring and flange surface with a clean cloth, and then apply vacuum grease evenly before closing the furnace door.

4. The workpieces of vacuum furnace must be cleaned before being put into the furnace for treatment. After oil quenching, all the oil on the oiled material frame and carrier parts shall be cleaned.

5. Air cooled motor is generally a common motor. If it cannot be started under vacuum, it can only be started after inflation and shall be protected by electrical interlocking protection device.

6. Roots pump can only be started when the vacuum degree is above 133Pa, and it shall also be protected by electrical interlocking protection device.

In addition, for the pipeline with compressed air, open the drain valve every day to drain the accumulated water. Pay attention to whether the inlet and outlet water temperature indication of the cooling water is normal, and check whether there is abnormal local temperature rise at the touch electrode connector, furnace door, transformer cooling water pipe and other parts.

Fault phenomenon, cause and treatment

1. Low vacuum: the pump oil is polluted, too little or too thin. Clean the vacuum pump and replace it with new vacuum pump oil.

2. The pumping time is too short: extend the pumping time.

3. The air extraction filter is blocked: clean or replace the exhaust filter.

4. Air leakage: turn off the power after evacuation, and check whether there is air leakage at the solenoid valve, pipe connector, vacuum pump suction valve and the sealing gasket around the working room.

5. High noise: the vacuum pump coupling is worn or cracked, replace it.

6. The exhaust filter is blocked or installed incorrectly: clean or replace the exhaust filter and install it correctly.

7. Vacuum pump oil injection: the O-ring of the suction valve falls off, pull off the vacuum pipe on the pump nozzle, remove the air extraction nozzle, take out the pressure spring and the suction valve, gently stretch the O-ring several times, re insert it into the groove, and then install it.

8. Rotary vane wear: replace rotary vane.

9. Vacuum pump leaks oil: the oil return valve is blocked, remove the oil return valve and clean it (see the instructions for details).

10. The oil window is loose: after the oil is drained, remove the oil window and wrap it with raw meal tape or thin plastic film.