Medium frequency furnace cold start

The cold start process requires sufficient time for the lining material to undergo reversible expansion to seal the cracks due to thermal shock before any molten metal contacts the lining. Need to use cold start 3 ~ . 4 put K -type thermocouple temperature detector, a thermocouple need to be placed close to the furnace wall or bottom. For the intermediate frequency furnace, the temperature of the thermocouple in the middle of the effective coil is the control temperature. Gas combustion can also be added at the bottom of the furnace to help reduce the temperature difference between the upper part of the furnace and the entire lining.     

For example, 5 tons of furnace cold start time: within 2h , the solid material in the furnace is heated to 1100 °C (heating speed: 4t ~ 15t furnace does not exceed 150 °C / h , more than 15t furnace does not exceed 100 °C / h ), and After heat preservation at 1100 °C for 3 hours, the furnace charge is quickly melted after the end of the heat preservation and put into normal use. Start with a low power transmission, power is gradually increased (full power to 20% - 30% have 15min later), so that fine cracks when cooled to bridge the lining, and finally sent to full power).

Mid-frequency furnace start operation

1 ) Close the low-voltage switch box switch of the incoming line, observe whether the three-phase incoming line voltage and current meter indication are normal, and adjust the power adjustment potentiometer to the minimum value; 

2 ) Press the control power on button. After 2 to 3 seconds, press the “main circuit switch button” and then press the “inverter start button”. The intermediate frequency power supply starts to work. At this time, the DC voltage meter, ammeter, IF frequency meter, The power meter has instructions; 

3 ) After the startup is successful, slowly adjust the power knob to the required power position and input the power; if the intermediate frequency is not established (ie, start failure) , press the “inverter stop” button to reset it, and then press “inverter start” again. can.

 Medium frequency furnace shutdown operation

1 ) When stopping, first turn the power button to a smaller position, then press the “inverter stop” button. 

2 ) If it takes a long time to stop, first press “inverter stop”, then press the main current disconnect button, and finally press the “control power off” button. (The above steps can not be reversed!) At this time, the internal circulating cooling water of the intermediate frequency power supply and the electric heating capacitor can be turned off (refer to stop the circulating water pump operation of the system), and the internal and external circulation system of the furnace body should be cooled to 100 °C. In the following (generally 72 hours), the pump can be stopped and the water can be stopped.   

3 ) When cooling water is stopped in winter, it must be considered that the water in the pipeline will freeze and crack the water pipe (heating, draining water, adding water glycol, etc.).