How to control the temperature of the induction melting furnace?
Automatic temperature control of induction melting furnace-refers to automatically turn on or off the heat source energy supplied to the furnace according to the deviation of the furnace temperature to a given temperature, or continuously change the size of the heat source energy, so that the furnace temperature is stable and has a given temperature range To meet the needs of heat treatment process.
There are two-position, three-position, proportional, proportional integral, etc., commonly used regulation rules for the automatic control of heat treatment temperature.
1. Proportional adjustment (P adjustment)-the output signal (M) of the regulator is proportional to the deviation input (e). which is:
In the formula: K—–proportional coefficient, there is a corresponding proportional relationship at any time between the input and output of the proportional regulator, so when the furnace temperature change is balanced by the proportional adjustment, the furnace temperature cannot be added to Deviation at a given value-called “static error”
2. Proportional integral (PI) adjustment–In order to “static difference”, add integral (I) to adjust the integral in the proportional adjustment. Adjustment means that the output signal of the regulator and the deviation increase with time, until the deviation is eliminated. There is no output signal, so the combination of proportional adjustment and integral adjustment that can eliminate the “static difference” is called proportional integral adjustment.
3. Two-position adjustment-there are only two states: on and off. When the furnace temperature is lower than the set value, the actuator is fully open; when the furnace temperature is higher than the set value, the actuator is fully closed. (Actuators generally use contactors)
4. Three-position adjustment-it has two given values of upper and lower limit, when the furnace temperature is lower than the given value of the lower limit, the entertainment device is fully opened; when the temperature of the furnace is between the given value of the upper limit and the lower limit, the actuator is partially opened ; When the furnace temperature exceeds the upper limit given value, the actuator is fully closed. (For example, when the tubular heater is a heating element, three-position adjustment can be used to realize the difference between heating and holding power)