JPH03181771A - Food thawing control device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a thawing control device for foods stored frozen in a refrigerator.

Conventional technology To thaw food stored frozen in a conventional refrigerator-freezer, the temperature of the frozen food A is set at the center of the thawing turntable 6 installed at the bottom of the thawing chamber 2, as shown in FIG. A temperature sensor 12a is installed to measure food A, which changes when defrosted.
or, as shown in FIG. 6, an infrared sensor 12b is installed at the center of the top surface of the thawing chamber 2 and placed on the turntable 6 at the bottom of the thawing chamber 2. There are some devices that detect the temperature of frozen food A by detecting infrared rays radiated from the food.

<Problems to be Solved by the Invention> However, in the food temperature measuring means shown in FIG. As a result, the surface temperature of the food is different between the surroundings and the top and bottom, making it impossible to accurately detect the temperature. If the temperature sensor is held more afloat, it will not be possible to maintain contact between the temperature sensor and the food, making it impossible to accurately measure the temperature.

In addition, the method shown in Figure 6 measures the infrared rays radiated by the food, so it measures the temperature of the hottest surface of the food, that is, the top surface that is most in contact with hot air. As a result, the average temperature of the food cannot be determined, leading to the erroneous judgment that the center of the food indicates the thawing temperature when it is frozen.

Therefore, the present invention aims to eliminate the drawbacks of the above-mentioned conventional examples and provide a thawing control device that detects accurate thawing temperatures for foods of various sizes based on the relationship between the size of the food and the surface temperature. .

<Means for Solving the Problems> The present invention consists of a means for detecting the thickness of frozen food, a means for detecting the temperature of the frozen food, a means for generating warm air, and a microcomputer for calculating the time required for thawing.

Simultaneously with the start of the thawing operation, hot air is brought into contact with the frozen food, and the thickness of the frozen food is detected by the thickness detection means for the frozen food placed in the thawing chamber, and the temperature detection means is used to detect the thickness of the frozen food at the initial stage of thawing. The temperature of the food and the temperature thereafter at each pre-programmed time are sequentially detected, and a microcomputer calculates the time required to reach the predetermined final thawing temperature while controlling the hot air generating means based on the thickness and temperature of the food. At the scheduled time, the thawing operation is stopped and the operation is switched to low-temperature storage.

<Example> Hereinafter, the present invention will be described in detail with reference to the embodiment shown in the drawings. FIGS. Inside, a turntable 6 driven at a constant speed by a motor 5 is installed on the central upper surface of a bottom plate 4 with an air passage 3 formed at its lower part, and a turntable 6 is installed at the back of the thawing chamber 2, that is, connected to the bottom plate 4. A cold air intake tag 9 leading to the air passage 3 is formed on the back of the wall plate 4', and a gunper 10 is provided which is opened and closed by a motor 11 (FIG. 2) operated by a driver circuit 22. Install.

A heater 7 controlled by a thyristor 20 is provided in a space communicating with the cold air intake tag 9 at the back of the rear wall plate 4'', and the warm air generated by the heater 7 is formed in the rear wall plate 4''. A seven motor 8 is installed for blowing air into the thawing chamber 2 from the air outlet 4'', and the seven motor 8 is connected to a thyristor 21.
It is set to be controlled by.

The main point of the present invention is that the thawing chamber 2
A detection plate 13 is pivotably mounted on the tip of an arm 14 that is integrally attached to the drive shaft of a motor 15 installed at a position offset from the top surface of the turntable 6. Place it directly above the frozen food A above.

A temperature sensor 12 for measuring the temperature of the frozen food is attached to a suitable place on the lower surface of the detection plate 13, and a signal line is connected to the microcomputer 18 (hereinafter simply referred to as microcomputer) through the arm 14. ) of A
Connect to /D input port. (b) The microcomputer 18 includes a program ROM.

It should be noted that various functional circuits such as data RAM and ALU are accommodated.

A resistor 16 that can change the resistance value in conjunction with the drive shaft of the motor 15 is connected to the motor 15 that swings the arm 14 up and down, and is proportional to the rotation angle of the arm. The resistance value is taken out and A of the microcomputer 18 is
/D I am trying to input the information to the user's board.

Furthermore, the vertical movement of the arm 14 is configured to be operated by a driver circuit 17 in response to a signal output from an output port of a microcomputer 18.

Incidentally, in the above, a torque limiter mechanism is provided in the drive section of the arm 14, or a pressure sensitive element is attached to the lower surface of the detection plate to automatically control the rotation limit of the arm. Further, the reference numeral 2'' in the figure is a front door plate.

Next, the operation of the present invention will be described. First, when the initial state is set, the frozen food A to be thawed is placed and held on the top surface of the turntable 6 in the thawing chamber 2, as shown in FIG. In this state, the detection plate 13 is located at the upper level, and although the inside of the thawing chamber 2 is initially in a low temperature state, the microcomputer 18 is operated by the input according to the initial state from the temperature sensor 12 to operate the driver circuit 22. death,
The motor 11 operates the gunper 10 so that the cold air intake tag 9 is closed.

Once all the preparations have been completed as described above, microcontroller 1
8, the reference clock oscillator 19 oscillates a clock pulse for microcomputer operation, and the microcomputer, in synchronization with this, sequentially reads instructions from the program ROM and starts executing them.

First, the driver circuit 17 operates to drive the motor 15.
The arm 14 rotates by an angle of deviation a from the state shown in FIG. 3(a) to the state shown in FIG. 3(b), and the detection plate 13 comes into contact with the frozen food A. The resistance value corresponding to the declination angle a of the arm 14 is detected and the data is read from the A/D input port, and FIG. becomes larger than α, and a corresponding resistance value is detected from the resistor 16.

At the same time, the temperature sensor 1 facing the bottom surface of the detection plate 13
2 detects the temperature of the frozen food A and inputs data regarding the temperature from the A/D input port of the microcomputer 18.

The temperature inside the thawing chamber 2 is set in advance as shown in FIG. 4(c), and the input power to the heater 7 is controlled by the microcomputer program.
-20 degrees), the thyristors 20 and 21 are made conductive according to a command from the microcomputer, the heaters 7 and 7 are energized, and the unmotor 8 is energized to blow hot air from the outlet 4'' into the thawing chamber 2.
Feed it inward as shown by the arrow, and pass through the air passage 3 again to the heater 7.
．． 7 Start circulation to the space around the unmotor 8. At this time, the hot air from the air outlet 4'' becomes as shown in Fig. 4(a), and remains open at 40['C] until time t4, and then remains open at 10['C] until the defrosting setting end time T. ], and accordingly, the temperature distribution of the frozen food A stored in the thawing chamber 2 becomes as shown in FIG. 4(a).

That is, the temperature distribution of the frozen food A can be determined by tilting the arm 14 as shown in FIG.
maintains contact for the time t required to detect the temperature of frozen food A, and otherwise moves upward so as not to prevent the hot air from acting on the food A, and performs the process programmed in the microcomputer ■8 in advance. Open at a certain time. ft2...t4, the temperature is detected each time it comes into contact with the surface of the food A, and the rotation of the turntable 6 is automatically stopped while the detection @13 is in contact with the frozen food A. In this way, when the frozen food A reaches the desired set temperature -3E°C at the thawing end setting time MT,
4(d) in which the input power to the heater 7 is cut off and the goomba 10 of the cold air intake tag 9 is programmed in advance.
The door is opened according to the operation chart 7, and cold air is taken in by the rotation of the 7-unmotor 8, and the thawed food A is stored at a predetermined temperature so as not to rise to a temperature higher than necessary.

The present invention provides frozen food A stored in the thawing chamber 2 as described above.
By measuring the thickness of the food at the initial stage of thawing and determining the temperature of the food at that point, the required thawing time T until the thawing temperature set by the Hamamaki is reached is determined from the data stored in the microcomputer in advance, and the required thawing time T is determined at the low temperature. It automatically switches to the holding state.

<Effects of the Invention> Since the present invention is configured as described above, the temperature is measured by bringing the temperature sensor into direct contact with the frozen food, so that an accurate value can be obtained.

Then, the thickness of the food is detected from the angle at which the detection plate is applied to the food, and the amount of heat required to reach the required defrosting temperature is calculated accordingly to determine the required defrosting time.
There is no risk of the food being overheated or under-thawing, and in terms of operation, all you have to do is place the frozen food in the thawing chamber, set the thawing temperature, and press the thaw start button, and everything is done automatically. This process does not require any effort.

Since the detection plate only comes into contact with the frozen food when measuring the thickness and temperature of the food, it does not interfere with the circulation of warm air and can average the temperature over the entire surface, making it possible to accurately grasp the temperature.

Furthermore, since the temperature of the food is periodically measured by a temperature sensor until the food reaches a certain temperature, the transition of temperature change can be accurately captured, and the reliability of the results is significantly improved.

Further, by incorporating the temperature sensor into the detection plate, the structure can be made more compact and the structure can be made more compact, and the occurrence of failures can be reduced, which is an advantage unique to the present invention.

[Brief explanation of drawings]

#&1 Figures to Figure 4 show embodiments of the present invention, and Figure 1 is
Figure 2 is a functional block diagram of the same as the above; Figure 3 (a) is a schematic side view showing the state before the start of defrosting; Figure 3 (b) is the state in which thick food is detected. Figure 3(e) is a schematic side view of the state in which thin food is detected; Figure 4(a) is a diagram of time vs. temperature distribution characteristics of the thawing chamber and frozen food; Figure 4(b) is , a time chart showing the vertical movement of the detection plate, tIfJ4 (e) is a control characteristic diagram of the heater input, the fourth
FIG. 5D is a time chart showing the operation of the damper, and FIGS. 5 and 6 are schematic side views showing conventional examples of different temperature detection means.

Claims (1)

[Claims] 1. A means for detecting the thickness of the frozen food by contacting the frozen food held at a predetermined position in the thawing chamber; a means for sequentially detecting the temperature of the frozen food provided in the thickness detecting means; and a hot air generating means. and a microcomputer that calculates the time required for thawing from the output from the thickness detecting means and the sequentially detected temperature of the frozen food to the set thawing temperature of the food.