Working principle of purifying hot air circulation oven
The working principle of the purification hot air circulation oven: When the temperature reaches the set value, the temperature controller outputs a PID control signal PLC, and the PLC outputs a control signal to the time relay KT to start the insulation timing. At the same time, the inlet fan and exhaust disc valve are closed. By using PID control to continuously open and close the electric heating, the box is in the stage of hot air circulation and insulation. When the insulation time reaches the set value, the time relay outputs a signal to the PLC, which outputs a fully closed electric heating and opens the water cooling solenoid valve, causing it to close and conduct, thus putting the box in the cooling and cooling stage.
The temperature control of the box adopts GCD-23A intelligent computer temperature control and PLC self-control system. The temperature signal is collected by platinum resistance, and the PID control signal is obtained by amplifying and comparing with the set value of the temperature controller. At the same time, the PLC program controller outputs the control signal to control the solid-state relay SSR to conduct, and the solid-state relay then controls the heater heating to keep the box in the heating and dehumidification stage.
When the temperature inside the box drops by ≤ 40 ℃, the temperature controller outputs a control signal to the PLC, which outputs to turn off the hot air circulation fan, and the drying cycle program ends. TEED -2001K overtemperature alarm temperature controller outputs a signal to control the operation of the entire PLC program. The platinum resistance PT100 test signal is sent to the alarm temperature controller to compare with the set temperature value of the overtemperature alarm. When the actual temperature value is lower than the set value, the control signal is output to the PLC, and the PLC program runs normally. When the actual temperature value exceeds the set value, output a control signal to the PLC, and the PLC will shut down the running program. Therefore, the set value for the over temperature alarm is generally higher than the set value for the operating temperature.
