JPS6010706B2 - Defrosting control method using infrared detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION An object of the present invention is to provide a method for automatically completing defrosting using an infrared detector.

To measure the temperature of hard foods like frozen foods, non-contact temperature measurement devices such as infrared detectors are more practical and easier to use than devices that require a thermistor or thermocouple inserted into the food.

There is no problem if the food is thin, but frozen food with a large volume tends to have a large difference in internal temperature between the surface and the food.
Even if the surface temperature reached the set level, if heating was stopped at that point, a large portion of the interior would often remain in the form of ice.

The present invention relates to a method for solving this problem.

The basic concept of the method of the present invention is as follows: When food is heated for a certain period of time (until the surface reaches a set level), the surface temperature rises rapidly, and the interior remains at a low temperature.

Therefore, when heating is stopped, heat is leveled out between the high temperature part on the surface and the low temperature part inside, and the surface temperature becomes lower than when heating was stopped. The degree of this reduction is a function of the type, thickness, and volume of the food.

That is, it is determined by the temperature difference between the surface and the inside and the thermal conductivity. However, the initial temperature of the food plays a large role in the time from the start of freezing until it reaches the set level.
It is not suitable for determining the timing of completion of defrosting.

FIG. 1 shows an embodiment of the present invention.

1 is a heating chamber, 2 is a food tray, 3 is food, and 4 is an infrared detector.

FIG. 2 shows an example of changes in the detection signal.

After the detection signal reaches the set level, there is a pause for a certain period of time, and then the cycle of heating is repeated until the set level is reached.

As the cycle is repeated, the temperature difference between the inside and the surface becomes smaller, so that the difference ΔS between the signal that decreases within time T and the set level becomes smaller with each cycle. Heating is completed when this ΔS becomes smaller than a preset threshold value ΔS(m).

Or, after heating is stopped, the time TN required for heating to reach the set level is the set threshold value TN (ratio).
Control is performed such that the completion point is when the value becomes smaller than .

With this kind of control, thin-walled items can be thawed in a short cycle, and thick-walled items can be thawed in a long cycle, and once the set level has been reached. Since the timing is determined using signal changes from It goes without saying that when the next heating cooking (such as stewing) is to be performed, the heating cooking can be started at the completion of this cooking. As described above, according to the thawing control method using an infrared detector of the present invention, the timing of thawing completion is automatically determined based on the change in the signal after the infrared temperature detection signal reaches the set level once. Uniform heating is possible regardless of the type and initial conditions.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a diamond counterfeit for carrying out the defrosting control method of the present invention, and FIG. 2 is a characteristic diagram of a detection signal for 0 to explain the method of the present invention. 1... Heater, 4... Infrared detector. Leopard 1 illustration, 2 traditional illustrations

Claims (1)

[Claims] 1 Using an infrared temperature sensor, a certain period of time T is elapsed after the signal that measures the surface temperature of the food reaches the set level.
The cycle of stopping heating and then heating to a set level is repeated, and the time interval Tn from the start to the stop of heating or the level difference ΔS of the detection signal between the time of stopping and starting of heating is set at a preset threshold. Hold value Tn(th)
A thawing control method using an infrared detector, characterized in that the timing of thawing completion is set at the time when the value becomes smaller than ΔS(th).