Method of heating and controlling cabinet-type electric furnace

Abstract

The invention provides a heating control method of a box electric furnace, which relates to the industry box electric furnace heating control technology field of bearing part quenching. The method comprises the following steps that the gate of the box electric furnace is closed and a furnace gate safe device is connected a three-phase AC power source with a AC SSR; a PID temperature control meter is used to test the temperature of the industry box electric furnace and the working temperature of the PID temperature control meter is set according to the temperature of the process technique to make the PID temperature control meter output 4mA to 20mA current signal; the current signal is received by a pulse triggering circuit to generate a zero passage periodic wave output signal to the SSP, the SSP is communicated with the box electric furnace through the zero passage periodic wave, and then the box electric furnace is communicated with the three-phase AC power source; the electried box electric furnace is started to be heated till the process technique temperature. The invention is capable of continuously controlling and slightly adjusting the current load heating power of the box electric furnace, and the make-and-break of the load current is distributed according to the sine wave. The more exquisite the temperature of the electric furnace is regulated, the higher the precision is.

Description

technical field [0001] The invention relates to the technical field of heating control of an industrial box-type electric furnace for quenching bearing parts, in particular to a heating control method of a box-type electric furnace. Background technique [0002] The heating control circuit of the existing industrial box-type electric furnace for quenching bearing parts mainly includes three parts: the main circuit, the temperature control circuit and the electrical operation circuit. Among them, the main circuit part uses a traditional AC contactor, that is, an electromagnetic switch, to connect or disconnect the connection between the box-type electric furnace and the main power supply. This part uses mechanical contacts to connect the power supply to the box-type electric furnace load—electric heating The disadvantage is that the mechanical contact is easy to generate electric sparks, so there is considerable mechanical wear; the temperature control circuit part adopts the...

AI Technical Summary

Problems solved by technology

Among them, the main circuit part uses a traditional AC contactor, that is, an electromagnetic switch, to connect or disconnect the connection between the box-type electric furnace and the main power supply. This part uses mechanical contacts to connect the power supply to the box-type electric furnace load—electric heating The disadvantage is that the mechanical contact is easy to generate electric sparks, so there is considerable mechanical wear; the temperature control circuit part adopts the traditional large circle diagram instrument, the position control instrument, to control the furnace temperature of the box-type electric furnace. The disadvantage of this part is The temperature control is unreliable, the internal micro switch is prone to failure, and contact adhesion often occurs, resulting in overheating of the electric furnace; the electrical operation circuit uses a simple electromagnetic intermediate relay to control the AC contactor for heating. The disadvantage of this part is that the electromagnetic type If the intermediate relay and electromagnet have been working for a long time, it is easy to have unreliable contact work or contact adhesion. The residual magnetism of the electromagnet will cause the controlled AC contactor to work all the time, which will cause overheating of the electric furnace and seriously affect the processed bearings. The quenching quality of the parts is improved, and even the processed bearing parts become waste products

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