Cold start of Intermediate frequency induction melting furnace:
The cold start process needs to give the lining material enough time to undergo reversible expansion to seal cracks due to cold and heat impact before any molten metal contact the lining.3 ~ 4 K thermocouple should be used to check the temperature during the cold starting process. The thermocouple should be placed close to the furnace wall or bottom. For an intermediate frequency furnace, the effective central thermocouple temperature of the coil is the control temperature. Gas can also be added at the bottom of the Intermediate frequency induction melting furnace to help reduce the temperature difference between the top of the furnace and the entire lining.
For example, the cold start time of 5t Intermediate frequency induction melting furnace: heat the solid material in the furnace to 1100℃ within 2h (heating speed: 4T ~ 15T furnace no more than 150℃/h, no more than 15T furnace no more than 100℃/h), and hold the heat at 1100℃ for 3h, after the end of heat preservation, quickly melt the furnace material and put it into normal use. Start to use low power transmission, gradually increase the power (up to 20%-30% of full power for 15min), make the fine cracks appear during the furnace lining cooling, and finally fill the power).
Boot operation of Intermediate frequency induction melting furnace:
1) Close the low-voltage switch frame of the incoming line, observe whether the three-phase incoming line voltage and ammeter indication are normal, and adjust the power potentiometer to the minimum value;
2) Press the control power supply switch on the button. After 2 ~ 3 seconds, press the “main circuit switch on the button” and then press the “inverter start button”. If the power supply starts to work, the DC voltmeter, ammeter, if frequency meter and power meter all have instructions;
3) After a successful start, slow down the power knob to the required power position and input power;If the intermediate frequency is not established (i.e., startup failure), press the “inverter stop” button to reset it, and then press “Inverter Start” again.
Stop operation of Intermediate frequency induction melting furnace:
1) When the machine stops, first turn the power adjustment button to a smaller position and then press the “inverter stop” button.
2) If the machine needs to stop for a long time, press “inverter stop” first, then press the “disconnect control power” button, and finally, press the “Disconnect control Power” button. (The above steps should not be reversed!)At this point, the internal circulation cooling water of the intermediate frequency power supply and the electric heating capacitance (refers to the stop of the circulating water pump operation of the system), and the internal and external circulation system of the furnace body should wait for the furnace lining surface temperature to lower than 100℃ (generally after 72 hours), to stop the pump, stop the water operation.
3) When the cooling water is stopped in winter, it must be considered that the water inside the pipeline will freeze and crack (heat preservation, dry water discharge, water ethylene glycol, and other methods can be used).