Common faults and treatment methods of vacuum furnace

    If the vacuum furnace is not used for a long time or used for more years, some failures will inevitably occur. The following briefly introduces the common failures of the vacuum furnace and the corresponding treatment methods.

1. Electrical failure

(1) Abnormal temperature, including over-temperature alarm, or display temperature not reaching the set value.

(1) The method of clearing the over-temperature alarm fault:

1. First check whether the parameters of the thermostat in the working area are normal, and check all the parameters with reference to other thermostats in normal use.

2. According to the circuit diagram, check whether the output terminal of the solid state relay in the corresponding working area is broken down,

With this method: after power failure, use a multimeter to measure the resistance between two points at the output of the solid state relay. Normally, the resistance will be more than a few megohms. If it is broken down, there will be almost no resistance. You must replace it with the same model. new.

3. When the power is turned on, gently shake the thermocouple probe in the corresponding work area by hand to see if the corresponding thermostat shows a large fluctuation range. If this phenomenon occurs, it means that the thermocouple probe is in poor contact and needs to be replaced with a new one. of.

(2) The display temperature is too low to reach the set value:

1. Similarly, first check whether the parameters of the thermostat in the working area are normal and whether there is an output signal.

2. Check whether the thermocouples in the corresponding working area are damaged. In order to verify whether these thermocouples are in good condition, you can interchange them with the thermocouples on the normal thermostat and connect them to the thermostat to observe the temperature display. If the thermocouple is indeed damaged, it must be replaced. (Note: If the thermocouple to be replaced is in the inner cavity, the vacuum sealing performance will also be involved, and the details will be explained in addition)

3. If there is no problem with the thermostat and thermocouple, you need to test whether the heating tube is energized and working normally. Method: After the power is turned on, start the heating. According to the circuit diagram, directly use a test pen to test the wire connected to the heating tube in the corresponding work area (the white high temperature wire on the solid output terminal is the same) to see if there is electricity. If electricity arrives, you need to use a clamp meter to measure whether the current is different from other working areas. Normally, the difference is not big.

4. If no electricity arrives, you must check the circuits one by one according to the circuit diagram to see at which link the electricity is cut off, and whether any components are burned out?

(2) Abnormal phenomenon of vacuum

The vacuum cannot be drawn up or is too low:

1. First confirm whether the vacuum source is normal (above -95KPa) and the compressed air pressure is normal (normal use range is 0.4-0.6 MPa).

2. Check whether the vacuum meter is in good condition, and compare it with the vacuum meter in normal use to see if the parameters are normal?

3. Check whether the door is closed tightly, whether the sealing film at the door is damaged or deformed, and whether there is foreign matter on the door panel? please check carefully!

4. If there is no problem with the door, you need to check the corresponding work area pipeline, pneumatic valve, thermocouple entry and other locations. Usually there are more cases at the entrance of the thermocouple, because if there is a replacement of the thermocouple, the vacuum sealing performance will often be destroyed, and the AB glue must be re-sealed for sealing.

2. Mechanical structure failure

1. The door is not closed tightly. Check whether the hinge of the door is loose, whether the pull buckle is deformed, whether the sealing strip at the door is damaged, and whether the door panel is deformed?

2. The fan has abnormal noise. Please check carefully whether foreign matter enters the wind wheel of the fan, or whether the screws fixing the motor are loose.

3. If the pneumatic valve cannot be operated, first check whether the corresponding solenoid valve can work normally and whether the compressed air pressure meets the working requirements? If the air pressure is normal and the solenoid valve is also good, the pneumatic valve must be broken and must be replaced.