JPH0442710Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an improvement of a defrosting device that controls power on/off of a heater using a sensor that detects the temperature of a defrosting plate.

[Technical background of the invention]

Conventionally, for example, a refrigerator equipped with a thawing chamber,
A thawing plate on which frozen food is placed is installed in the thawing chamber, and a heater is attached to the back side of the thawing plate, and a sensor is attached to detect the temperature of the thawing plate, and the on-temperature detected by the sensor is attached. There is also provided a configuration in which the heater is controlled to be energized and cut off in accordance with the off temperature, thereby thawing the frozen food through heat exchange with the thawing plate.

[Problems with background technology]

In the case of such a conventional configuration, the frozen food is thawed quickly by the heat generated by the heater, but in reality, it is caused by variations in the sensing operation of the sensor, changes in the ambient temperature, or thawing of the frozen food. Since there are unstable factors in the heater power-on/off control, such as contact with the plate, the temperature distribution of the frozen food may be extremely uneven, such as when the heater is continuously energized and only the bottom of the frozen food becomes high temperature. In order to prevent extreme differences in thawing conditions due to
It is necessary to shorten the energization time of the heater by setting it significantly lower than theoretically.Therefore, there is a problem in that the effect of shortening the thawing time by using the heater cannot be fully demonstrated.

[Purpose of invention]

The present invention has been made in view of the above circumstances, and its purpose is to provide a thawing device that can sufficiently exhibit the effect of shortening thawing time by using a heater.

[Summary of the idea]

The present invention is characterized by a configuration in which power is cut off to the heater either when a timer element finishes measuring a unit time or when a sensor that detects the temperature of the defrosting plate detects an off temperature within the unit time. This is intended to prevent continuous energization of the heater.

[Example of idea]

An embodiment of the present invention will be described below with reference to the drawings.

First, the overall configuration will be described according to FIGS. 1 and 2. Reference numeral 1 denotes a refrigerator main body made of a heat insulating casing, the interior of which is partitioned into an upper freezer compartment (not shown), a thawing compartment 2 in the middle, and a refrigerator compartment 3 in the lower part. Reference numerals 4 and 5 designate doors pivoted to the front openings of the thawing chamber 2 and the freezing chamber 3 to open and close them.
Reference numeral 6 denotes a partition wall that separates the defrosting chamber 2 and the refrigerator compartment 3, and this partition wall has an intake hole 6a at the rear and an exhaust hole 6b at the front. Reference numeral 7 denotes a defrosting plate disposed on the partition wall 6, and a heater 8 is attached to the back surface in a meandering manner, and a sensor 9 for sensing the temperature of the defrosting plate 7 is attached to the center of the back surface. ing. Reference numeral 10 denotes a fan motor disposed deep inside the defrosting chamber 2, and is adapted to drive the fan 11 to rotate. 12 is the thawing chamber 2
It is a meat plate placed on the inside upper part.

Now, referring to FIG. 3, the electrical configuration will be described. 13 is the thawing time T, for example, 3 stages of 60 minutes and 90 minutes.
Time setting button for selective setting to minutes and 240 minutes,
Reference numeral 14 denotes a defrost button for selecting a defrost operation, and the time setting signal S ₁₃ from the time setting button 13, the defrost signal S ₁₄ from the defrost button 14, and the temperature sensing signal S ₉ from the sensor 9 are sent to the input circuit 15. The signal is supplied to an input port of a microcomputer 16 which is a control circuit. The microcomputer 16 operates as described later to generate a motor drive signal S _16a and a heater drive signal.
S _16b is selectively output, and output circuit 1 is output accordingly.
The fan motor 10 and the heater 8 are controlled to be energized and disconnected via the fan motor 10 and the heater 8 .

Next, the operation of this embodiment will be explained with reference to the temperature characteristic diagrams shown in FIGS. 4 to 6 and the flowchart shown in FIG. 7. The operation of the microcomputer 16 is clear from the flowchart shown in FIG. Therefore, the following description will be mainly based on the temperature characteristic diagrams shown in FIGS. 4 to 6.

() Example of Fig. 4 Now, with the frozen food 18 placed on the thawing plate 7, use the time setting button 13 to set the thawing time T to 60 minutes, 90 minutes, or 240 minutes depending on the quality or quantity of the frozen food 18. Select one of the following and set the time setting signal accordingly.
Output _S13 and operate the decompression button 14 to receive the decompression signal.
When S ₁₄ is output, the microcomputer 16
causes the defrosting time counter, which is a built-in timer element, to start counting the defrosting time T (timekeeping operation), and also causes the unit time counter, which is a timer element, to count a predetermined time (e.g., 20 minutes) (timekeeping operation). (See step A in Figure 7). As a result, the microcomputer 16 outputs a motor drive signal _S16a to start energizing the fan motor 10, and at this time, since the sensor 9 is sensing the ON temperature (lower limit set temperature), the heater drive signal S16a is output. _16b to start energizing the heater 8 (see steps B and C in FIG. 7). As a result, the heater 8 generates heat and heats the defrosting plate 7, and the fan motor 10
rotates the fan 11, and the fan 11 circulates the air in the refrigerator compartment 3 so that it is sucked into the thawing chamber 2 through the intake hole 16a and then discharged into the refrigerator compartment 3 through the exhaust hole 16b. Thawing of food 18 is started. In this way, as the thawing plate 7 heats the frozen food 18, the temperature rises (see steps d and e in FIG. 7), and when the temperature sensed by the sensor 9 reaches the off temperature (upper limit set temperature), The microcomputer 16 stops outputting the heater drive signal _S16b , and the heater 8 is cut off (7th
(See steps d and f in the figure). Therefore, the temperature of the thawing plate 7 begins to decrease due to heat exchange with the frozen food 18 (see steps ① and ② in Fig. 7), and then,
When the sensor 9 senses the on-temperature again, the microcomputer 16 outputs the heater drive signal _S16b , and the heater 8 is energized (see steps C and C in FIG. 7). Thereafter, in the same manner, the sensor 9 senses the off temperature and the heater 8 is de-energized, and then the sensor 9 senses the on-temperature and the hinge 8 is energized, and the unit time counter is set for the predetermined time _T1. When the counting operation of T 1 is completed (T ₁ = 0), the microcomputer 16 causes the unit time counter to start counting operation of the unit time T ₂ (for example, 7 minutes) (steps (E) and 7 in FIG. 7). ). Then, when the temperature of the defrosting plate 7 rises (see steps W, F, and T in FIG. 7) and the sensor 9 detects the off temperature, the microcomputer 16
The output of the heater drive signal _S16b is stopped and the heater 8
The unit time counter is then reset in the middle of the counting operation (see steps W, R, and S in FIG. 7). As a result, the unit time counter has a counting time T ₂ ′ that is smaller than the unit time T ₂
It will be reset at (T ₂ ′<T ₂ ). Thereafter, when the sensor 9 detects the ON temperature, the microcomputer 16 outputs the heater drive signal _S16b to energize the heater 8, and causes the unit time counter to start counting the unit time _T2 again (the second (See steps RI, RU, RI, NU and O in Figure 7). Then, when the unit time counter finishes counting operation for unit time T ₂ without sensor 9 sensing the off temperature (T ₂ = 0), microcomputer 16 stops outputting heater drive signal S _16b . The heater 8 is turned off, and then the sensor 9
is forcibly turned off (see steps W, C, Y, and T in Figure 7). In addition, this forced off of the sensor 9 is as follows:
For example, this is carried out by setting or resetting latching means for latching the respective states to the off-sensing state when the sensor 9 senses the on-temperature and off-temperature. Thereafter, in the same manner, the microcomputer 16 outputs the heater drive signal S _16b every time the sensor 9 detects the on-temperature to turn the heater 8 on.
At the same time, the unit time counter starts counting operation for unit time T2, and the unit time counter starts counting operation for unit time _T2 .
When the sensor 9 senses the off temperature within unit time T ₂ , the output of the heater drive signal _S16b is immediately stopped and the heater 8 is cut off, and when the sensor 9 does not sense the off temperature within the unit time _T2 , When the unit time _T2 has elapsed, the output of the heater drive signal _S16b is stopped and the power to the heater 8 is cut off, which is repeatedly performed. When the above operation is performed, if the remaining time of the selected defrosting time T becomes equal to or smaller than the specified time α (for example, 10 minutes) (T≦α), the microcomputer 16 If the heater 8 is energized at that time, it is turned off (see steps T and N of FIG. 7). Therefore, after that, only the fan motor 10 is energized, and the fan 11 circulates the air in the refrigerator compartment 3 into the thawing chamber 2. In this way, when the defrosting time counter finishes counting the set defrosting time T (T=0), the microcomputer 16 stops outputting the motor drive signal _S16a and starts the fan motor 10.
With this, the defrosting operation is terminated (see steps N and A in FIG. 7).

() Case in Figure 5 In this case, the operation until the unit time counter of the microcomputer 16 finishes counting operation for the predetermined time _T1 is almost the same as in the case in Figure 4, but this predetermined time Since the sensor 9 has detected the off-temperature at the time T ₁ has elapsed, the microcomputer 16 does not cause the unit time counter to start counting immediately (see steps C, R, R and R in FIG. ). Then sensor 9
When the microcomputer 16 detects the ON temperature, the microcomputer 16 outputs a heater drive signal _S16b to turn the heater 8 on.
At the same time, the unit time counter starts counting the unit time _T2 (see steps R, N, and O in FIG. 7). The subsequent operation is the same as the principle described in _FIG .
The heater 8 is repeatedly cut off at some point when T ₂ has elapsed until the remaining time of the thawing time T reaches α, and when the thawing time T ends, the thawing operation is terminated.

() Case in Figure 6 In this case, the sensor 9 never detects the off temperature within the predetermined time _T1 (the heater 8 remains energized), so the microcomputer 1
6 causes the unit time counter to immediately start counting the unit time T ₂ after the predetermined time T ₁ has elapsed (see steps (e) and (e) in FIG. 7). Since the sensor 9 does not detect the off-temperature even within the unit time _T2 , the microcomputer 16 turns off the heater 8 and forcibly turns off the sensor 9 after the unit time _T2 has elapsed (see FIG. (See steps wa, ka, yo and ta). The subsequent action is the fourth
It is based on the principles described in Figures and Figure 5.

According to this embodiment, the following effects can be obtained. That is, within a predetermined time T ₁ (for example, 20 minutes) from the start of thawing, the heater ₈ is controlled to be turned on and off according to the temperature sensed by the sensor 9,
After the elapse of , every time the sensor 9 senses the ON temperature, it starts counting operation for a unit time T ₂ (for example, 7 minutes), and when the sensor 9 senses the OFF temperature within this unit time T ₂ or the unit time Since the heater 8 is cut off at any time when T ₂ has elapsed, there may be variations in the temperature sensed by the sensor 9, there may be a change in the ambient temperature, or the frozen food 18 may come into contact with the thawing plate 7. Even under various circumstances, the heater 8 can be prevented from being in a continuous energized state, and therefore, extreme non-uniformity in the thawed state, such as the temperature rising only on the bottom surface of the frozen food 18, is eliminated. As a result, the off-temperature sensed by the sensor 9 can be set higher than before, and the effect of shortening the thawing time using the heater 8 can be fully demonstrated.

The present invention is not limited to the embodiments described above and shown in the drawings, but can be modified as appropriate without departing from the spirit, such as being applicable not only to the defrosting chamber of a refrigerator but also to defrosting devices in general. Of course, it can be implemented.

[Effects of the invention] As explained above, in the present invention, the heater is cut off either when the sensor detects the off temperature within a unit time or when the unit time has elapsed. It is possible to prevent the heater from being continuously energized, and it is possible to set the off-temperature detected by the heater to be high, so that the effect of shortening the thawing time using the heater can be fully demonstrated. be.

[Brief explanation of the drawing]

The drawings show an embodiment in which the present invention is applied to a refrigerator, in which Fig. 1 is a longitudinal sectional view of the defrosting chamber, Fig. 2 is a perspective view of the defrosting plate, and Fig. 3 is a block diagram showing the electrical configuration. 4 to 6 are temperature characteristic diagrams for explaining the operation, and FIG. 7 is a flow chart for explaining the operation. In the drawings, 2 is a thawing chamber, 7 is a thawing chamber, 8 is a heater, 9 is a sensor, 10 is a fan motor, 13 is a time setting button, 14 is a thawing button, and 16 is a microcomputer 16 (control circuit).

Claims (1)

[Scope of utility model registration request] A heater attached to a thawing plate in a thawing chamber, a sensor that detects the temperature of the thawing plate, and a control circuit that controls turning on and off of the heater according to an on temperature and an off temperature detected by the sensor, The control circuit includes a timer element, and controls power-off of the heater for a predetermined time from the start of thawing according to the sensor, and after the predetermined time has elapsed, measures time every time the sensor detects an ON temperature. The thawing method is characterized in that the heater is configured to repeatedly cut off the power to the heater either when a unit time of operation has elapsed or when the sensor detects an off temperature within the unit time. Device.