Common Faults in Vacuum Furnaces and Their Solutions

A vacuum furnace refers to a method of removing substances within the furnace to achieve a vacuum state. Vacuum furnaces are widely used in smelting, ceramic firing, and other fields. Below, we introduce some common issues with vacuum furnaces.
Vacuum Furnace Malfunction:
Electrical failure
(1) Abnormal temperature conditions, including high-temperature alarms or the display of temperatures not reaching the set values.

Failure of High-Temperature Alarms and Improvement Methods
First, check if the temperature parameters in the work area are normal, and then refer to all the parameter certificates of other normal thermostats.
2. According to the circuit diagram, inspect if the solid-state relay's output is damaged in the corresponding operating area. Method: Cut off the power, and use a multimeter to measure the output resistance of the solid-state relay. Normal resistance should reach several megohms or higher. If damaged, there will be almost no resistance, and a new relay of the same type must be replaced.
After powering on, please shake the corresponding working area of the thermocouple probe to check if the thermostat has a significant fluctuation range. If this occurs, the thermocouple probe is not making good contact and needs to be replaced.
Temperature Display Below Set Value
Firstly, check the parameters of the temperature controller in the work area to ensure they are normal and that there is an output signal.
Next, inspect for any damage to thermocouples within the respective work area. To check if these thermocouples are in good condition, connect them to the thermostat and observe the temperature display. If the thermocouples are indeed damaged, they must be replaced. (Note: If the thermocouple to be replaced is located within the cavity, it will also involve vacuum sealing performance, and detailed instructions will be provided.)
Similarly, if the thermostats and thermocouples are functioning properly, the heating element must be tested for normal operation. Method: After turning on the power, start heating according to the circuit diagram, and directly use a testing pen to test the corresponding working area of the heating element connected to the wire (the solid output line under white high temperature is ), to see if there is power. If power is available, a fixed device is also required to check the current difference between the current working areas; in normal circumstances, this difference is not significant.
If the vacuum furnace lacks power, it is necessary to check the circuit diagram one by one to determine if the power failure has ended and whether any components have been damaged?
(2) Abnormal Vacuum Phenomenon
Vacuum extraction or low-pressure
Firstly, ensure that the vacuum source of the equipment is normal (-95KPa or above) and the compressed air pressure is within the normal operating range (0.4 to 0.6 MPa).
2. Check if the vacuum gauge is functioning properly. Are you using the vacuum gauge to view parameters normally?
Ensure the door is closed, check for any damage or deformation on the sealing film door, and verify if the door is contaminated by foreign objects. Please inspect carefully!
4. If there are no issues with the door, please inspect the corresponding work areas for the pipeline, pneumatic valve, thermocouple entry, etc. There is usually more at the thermocouple entry point, as the vacuum seal integrity is often compromised when replacing the thermocouple, necessitating the reapplication of AB adhesive for sealing.
2. Mechanical structure failure
Is the door not tight? Check if the hinges are loose, if the latches are deformed, if the door seal is damaged, or if the door is warped?
If the fan emits an unusual sound, please carefully check for any foreign objects in the fan or if the screws securing the motor are loose.
3. The pneumatic valve is unoperable. First, check if the corresponding solenoid valve is functioning properly and if the compressed air pressure meets the operational requirements. If the air pressure is normal and the solenoid valve is also in good condition, it is necessary to break the pneumatic valve and replace it.