Electric heating control circuit for air resistance furnace

Abstract

The invention discloses an electric heating control circuit for an air resistance furnace. The electric heating control circuit is composed of four stage heating control circuits, a main switch and a main control circuit. In the four stage heating control circuits, a first stage heating control circuit is used for controlling an air preheating section of the air resistance furnace, and a controlled electric heating element is arranged at the front end of the air resistance furnace and close to an air inlet; an electric heating element controlled by a fourth stage heating control circuit is arranged at the position close to an air outlet; and electric heating elements controlled by second and third stage heating control circuits are arranged between the first stage heating control circuit and the fourth stage heating control circuit. An external alternating current power supply is accessed through the main switch, and the four stage heating control circuits are arranged at the lower end of the main switch; and the four stage heating control circuits are connected with the main control circuit which sends drive signals and temperature setting signals to control the four stage heating control circuits.

Description

technical field [0001] The invention relates to a heating control circuit for an air resistance furnace. Background technique [0002] At present, heating appliances or equipment such as dry cleaning machines, electric water heaters, electric ovens and electric water heaters usually use resistance wires or silicon carbide rods for electric heating to realize the heating function. The air resistance furnace is an electric heating device that uses electricity as energy input to heat the ambient air to obtain high-temperature air. It can be used as a high-temperature air source in scientific experiments and industrial production processes. Due to the poor heat transfer performance of air, effective protection and precise control of electric heating elements are required. How to efficiently and safely convert electric energy into air heat energy, the key is to design a reasonable heating circuit. The existing heating control circuit mainly adopts the thyristor voltage regulati...

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Problems solved by technology

The existing heating control circuit mainly adopts the thyristor voltage regulation method to adjust the heating power. The main disadvantage is that when the thyristor adjusts the conduction angle, it will generate strong high-frequency interference to the external power supply, and it cannot be triggered by zero crossing, and the power output Can't start from scratch, output power is also very small

The air resistance furnace usually requires a large electric heating power, which can be adjusted from zero power to meet the adjustment of the air temperature, and the thyristor voltage regulation method cannot be applied

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