JPH08214850A - Thawing chamber and control of thawing operation in thawing chamber - Google Patents

Abstract

PURPOSE: To provide a method for controlling the thawing operation of a thawing chamber, capable of preventing the excessive rise in temperature in the thawing chamber and automatically performing the thawing operation for a proper time in response to the quantity of a frozen food. CONSTITUTION: When the quantity of a frozen food is small and when the temperature in a thawing chamber is liable to raise with heat penetrated from the outside through a heat-insulating box, etc., or when the temperature in a food-receiving chamber is higher than an upper limit thawing temperature TDH, a thawing temperature switch is switched to the side of a compressor motor to finish the heating operation of a heater and start a cooling operation. The food-receiving chamber is thereby chilled. Thus, the excessive rise of the temperature can be inhibited to prevent the deterioration in the quality of the frozen food due to the increase in drips from the frozen food.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thaw chamber provided with a heating device for heating the thaw chamber and a method for controlling the thaw operation thereof.

[0002]

2. Description of the Related Art A thawing chamber of this type is disclosed in, for example, Japanese Patent Laid-Open No. 63-
As described in Japanese Patent No. 17316, a heat-insulating box forms a thawing chamber for storing frozen foods, and a fan and a heater for sending hot air into the thawing chamber are provided.
It is equipped with a thawing operation control timer and a temperature sensor that detects the temperature of the air inside the thawing room, and when the thawing operation control timer sets the thawing operation time, the inside of the thawing room will be at a predetermined thawing temperature during the thawing operation time. The heater is on / off controlled.

[0003]

However, in the above-mentioned configuration, when the amount of frozen food is small, even if the heater is turned off, the heat entering from the outside that penetrates the heat insulating box and the self-heating of the internal fan causes There has been a problem that the temperature of the thawing chamber rises, causing an increase in drip from the frozen food. Furthermore, in the above configuration, since the setting time of the operation control timer has to be adjusted according to the amount of frozen food stored in the defrosting room, not only the trouble is involved, but also the setting time is determined based on the momentum. However, there is also a drawback that it is difficult to obtain appropriate thawing quality. Further, in order to shorten the thawing time, it is preferable to raise the temperature of the thawing chamber, but if it is excessively increased, there is a circumstance that the drip is increased and the thawing quality is deteriorated. Therefore, in order to avoid dripping and shorten the thawing time, it is conceivable to keep the temperature of the thawing chamber low at the beginning of the thawing operation and raise the temperature of the thawing chamber at the latter stage.

However, since there is a tendency that the change of the thaw chamber temperature is better when there are many frozen foods and earlier when there are few frozen foods, the timer setting time depends on the amount of frozen foods. Must be adjusted. For this reason,
After all, there was a problem that the effort was troublesome and it was difficult to obtain an appropriate thawing quality because the setting time was decided depending on the intuition. The present invention has been made in view of the above circumstances. Therefore, it is an object of the present invention to provide a thaw cabinet that can suppress an increase in temperature in the thaw chamber and obtain an appropriate thawed state even when the amount of frozen food contained is small. In addition, another object of the present invention is a defroster that can automatically perform a defrosting operation of an appropriate length according to the amount of frozen food and does not require time and effort such as adjusting the set time of a timer and the like. It is in the place of providing the thawing operation control method.

[0005]

According to a first aspect of the present invention, there is provided a thaw cabinet, which comprises a heat-insulating box which constitutes a thaw chamber for storing frozen foods.
The temperature inside the thawing chamber for detecting the temperature inside the thawing chamber, the heating device for heating the inside of the thawing chamber, the cooling device for cooling the inside of the thawing chamber, and the temperature depending on the temperature inside the thawing chamber detected by the temperature inside the thawing chamber Is provided with an operation control device for controlling the operation of the cooling device and the heating device so as to maintain the set temperature for thawing. Further, the thawing chamber according to claim 2 is a heat-insulating box forming a thawing chamber for storing frozen foods, a chamber temperature detecting means for detecting a temperature in the thawing chamber, a heating device for heating the thawing chamber, and a chamber. An operation control device is provided for executing the heating operation by the heating device when the temperature in the defrosting chamber detected by the internal temperature detecting means decreases to a predetermined lower limit temperature and for suppressing the execution of the heating operation when the temperature rises to a predetermined upper limit temperature. The operation control device has a timer that integrates the time during which the execution of the heating operation is suppressed, and the defrosting operation is terminated on the condition that the time integrated by the timer reaches the set time. There is a feature in the place.

Further, the thawing chamber of claim 3 is a heat insulating box which constitutes a thawing chamber for storing frozen food, a chamber temperature detecting means for detecting a temperature in the thawing chamber, and a heating device for heating the thawing chamber. And an operation control device for suppressing the execution of the heating operation when the temperature in the defrosting chamber detected by the in-compartment temperature detecting means decreases to a predetermined lower limit temperature and the heating operation is performed by the heating device and increases to a predetermined upper limit temperature. The operation control device has a timer for integrating the time during which the execution of the heating operation is suppressed, and the upper limit temperature is increased on the condition that the time integrated by the timer reaches a predetermined time. The feature is that the configuration is changed.

Further, a thaw operation control method in a thaw chamber according to a fourth aspect of the present invention is a heat-insulating box forming a thaw chamber for storing frozen foods, a chamber temperature detecting means for detecting a temperature in the thaw chamber, and a thaw chamber. When the temperature inside the defrosting chamber detected by the heating device and the inside temperature detection means decreases to a predetermined lower limit temperature, the heating operation by the heating device is activated, and when it rises to a predetermined upper limit temperature, the operation of the heating device is suppressed In the thaw cabinet provided with the operation control device for controlling the thaw operation, the thaw operation is controlled based on the temperature change rate in the thaw chamber when the heating operation is executed or when the execution is suppressed.

[0008]

According to the first aspect of the invention, the operation of the cooling device and the heating device is controlled in accordance with the temperature detected by the inside temperature detecting means in the thawing chamber, and the thawing chamber is maintained at the set temperature for thawing. Therefore, if the frozen food is stored in the thawing chamber, the frozen food is warmed and thawed. When the amount of frozen food contained is small, even if the operation of the heating device is suppressed, the temperature of the thaw chamber may tend to rise due to heat entering from the outside that penetrates the heat insulating box. Then, the temperature detected by the in-compartment temperature detecting means rises, so that the cooling device operates and the rise in the in-compartment temperature is suppressed.

By the way, when the frozen food is stored in the thawing chamber and the temperature inside the thawing chamber drops to a predetermined lower limit temperature, the heating operation is executed, and when the temperature rises to a predetermined upper limit temperature, the execution of the heating operation is suppressed. In the refrigerator, the temperature change is said to increase to the upper limit temperature due to the execution of the heating operation, and when the execution of the heating operation is suppressed, the so-called cold heat of the frozen food reduces the temperature to the lower limit temperature and restarts the heating operation. Repeat the cycle. Therefore, when the amount of frozen food contained is large, the amount of cold heat is also large, so that it takes a long time to rise to the upper limit temperature and decrease to the lower limit temperature in a short time as shown in FIG. When the storage amount is small, there is a characteristic that the temperature rises to the upper limit temperature in a short time and slowly reaches the lower limit temperature as shown in FIG. This is
This means that the rate of temperature change in the thawing chamber when the heating operation is performed or when the heating operation is suppressed can be used as an index representing the amount of frozen food to be stored.

The invention of claim 4 is made in view of the above circumstances. Since the thawing operation is controlled on the basis of the temperature change rate in the thawing chamber, the thawing operation according to the stored amount of frozen food is executed. To be done. The inventions of claim 2 and claim 3 relate to a thaw cabinet embodying the above thaw operation control method. In the defroster according to claim 2, when a large amount of frozen food is stored, the temperature inside the refrigerator rapidly decreases, so that the time during which the heating operation is suppressed is shortened and the time of the timer of the operation control device is integrated. As a result, it is naturally compatible with the fact that the thawing operation is carried out for a long time and a large amount of frozen food is stored. On the contrary, when the amount of frozen food contained is small, the degree of decrease in the temperature inside the refrigerator is slow, so the execution of the heating operation is suppressed for a long time, and the accumulation of time by the timer proceeds early. After all, it naturally fits into the fact that the thawing operation is shortened and the amount of frozen food contained is small.

Further, in the thawing chamber of claim 3, since the upper limit temperature is changed during the thawing operation, the dripping increases and the quality is deteriorated unlike the thawing operation in which the upper limit temperature is set high from the beginning. In addition, the thawing can be carried out quickly as compared with the thawing operation in which the upper limit temperature is kept low until the end. In this case, when the storage amount of the frozen food is large, the time accumulation by the timer of the operation control device does not proceed and the change timing for raising the upper limit temperature is delayed, as in the case of the defroster of claim 2. Naturally compatible with the large capacity. On the contrary, when the storage amount of frozen food is small, the time accumulation by the timer is advanced early as in the case of the defroster of claim 2, and eventually the upper limit temperature is switched to a high temperature, and the storage amount of frozen food is increased. It naturally fits in that there are few.

[0012]

As described above, according to the thaw chamber of the first aspect, when the amount of frozen food contained is small, the cooling device operates to prevent the temperature of the thaw chamber from rising. The effect that quality can be obtained is obtained. Further, according to the method of controlling the defroster according to claim 4, an appropriate defrosting operation is automatically executed according to the amount of frozen food, without the need to adjust the timer every time the frozen food is stored. The excellent effect of And claim 2
In the defroster of claim 3, the defrosting operation of an appropriate length can be automatically performed according to the amount of frozen food, and in the defroster of claim 3, the upper temperature switching timing is automatically changed according to the amount of frozen food. Since there is no change in quality, the defrosting can be completed in a short time without degrading the quality, and the effect of eliminating the need to adjust the timer setting time again is obtained.

[0013]

【Example】

<First Embodiment> A first embodiment in which the invention of claim 1 is applied to a defrosting refrigerator will be described below with reference to FIGS. 1 to 3. (Structure of Embodiment) As shown schematically in FIG. 1, the thaw refrigerator of this embodiment has two vertically arranged inner boxes 12 inside a vertically elongated heat-insulating box 11 having an open front surface. A food storage chamber 1 in which a door 13 is provided on the front surface of the box 12 and the inside corresponds to a thawing chamber
4 is set. Each inner box 12 is formed of a heat conductive material such as stainless steel, and an air flow path 15 is formed between the outer periphery of the inner box 12 and the heat insulating box body 11. A machine room 16 is provided in the upper part of the heat insulation box 11, and inside thereof is housed each component constituting a well-known compression type refrigeration cycle such as a compressor, a condenser, a cooling fan, a capillary tube, etc. The cooler 17 is arranged in a cooler housing chamber 18 provided above the upper inner box 12 in the air flow path 15 of the heat insulating box 11. This refrigeration cycle corresponds to a cooling device for cooling the inside of the food storage chamber 14, and by operating the circulation fan 19 provided in the cooler storage chamber 18 while operating the refrigeration cycle,
The cool air generated by the cooler 17 can circulate in the air flow path 15 and cool the inner box 12 and thus the food storage chamber 14.

A heater 20 is attached to the bottom of the cooler 17, and the cooler 17 can be heated by energizing the heater 20. The heater 20 corresponds to the heating device according to the present invention and has a larger output than that of a normal defrosting heater, and not only defrosts the cooler 17, but also circulates while heating the cooler 17. By driving the fan 19, warm air can be circulated in the air flow path 15 to heat the inner box 12 and thus the food storage chamber 14. In addition, 21 is a shelf network for storing frozen food in the food storage chamber 14, 22 is a fan inside for circulating the air in the food storage chamber 14 as shown by an arrow, and 23 is a ceiling surface of the inner box 12. A temperature switch corresponding to the inside temperature detecting means attached to the refrigerating temperature switch T as described below.
It consists of h1 and a thawing temperature switch Th2.

Now, FIG. 2 shows a control circuit of a portion directly related to the present invention, which constitutes an operation control device. In the figure, the left and right power supply lines are connected to a commercial AC power supply, and the compressor motor 30 of the above compressor is connected.
Is connected to the power supply line through a normally closed relay contact x2, a refrigeration temperature switch Th1, a normally open relay contact x1, and a starter SR in series. This refrigeration temperature switch Th1
The configuration is such that the circuit is closed when the inside of the food storage chamber 14 reaches or exceeds the set refrigerating upper limit temperature TRH, and is opened when cooled to below the refrigerating lower limit temperature TRL. Further, the thawing temperature switch Th2 is a two-circuit switching type and is connected to the starter SR of the compressor motor 30 and the heater 20 via a normally open type relay contact x2, and the compressor motor is provided on condition that the relay contact x2 is closed. The heater 30 and the heater 20 can be selectively driven. The defrosting temperature switch Th2 activates the energizing path on the heater 20 side below the defrosting lower limit temperature TDL set in the food storage chamber 14, and activates the energizing path on the compressor motor 30 side when the defrosting upper limit temperature TDH is reached. It is a composition. The above temperatures are set to satisfy the relationship of TRL <THH <TDL <TDH in this embodiment (see FIG. 3).

Reference numeral 32 denotes a thawing start switch provided in an operation unit (not shown) of the thawing store, which is connected to both power supply lines through the timer switch 33 of the thawing timer TM2 and the relay coil X2 and is connected to the above thawing start switch 32. A self-holding normally open relay contact x2 is provided in parallel, and the timer motor 34 of the defrosting timer TM2 and the internal fan 22 are connected in parallel between both power supply lines in series with the relay contact x2. There is. Now, when the defrosting start switch 32 is pressed to close the circuit, the relay coil X2
Is excited to continuously energize the timer motor 34 and the internal fan 22.

Reference numeral TM1 in the figure indicates a defrosting timer. While the power of the defrosting refrigerator is turned on, the timer motor M is energized to perform the time counting operation, and the preset time is integrated. Then, the timer switch 36 is opened so that the relay coil X1 is de-energized. (Operation of Embodiment) When the power is turned on but the thawing start switch 32 is not turned on, the thawing refrigerator of this embodiment is in the refrigerating mode. That is, the relay coil X2 is cut off, the normally closed relay contact x2 is closed, and the normally open relay contact x1 is closed. Further, since the relay coil X1 is energized except during defrosting, the normally open relay contact x
1 is closed, the circulation fan 19 is operated, and the compressor motor 30 is in a state in which it can be energized. Therefore, when the temperature in the food storage chamber 14 exceeds the refrigerating upper limit temperature TRH set for refrigeration, the refrigerating temperature switch Th1 is closed and the compressor motor 30 is operated to cool the refrigerator. In addition, the inside of the food storage chamber 14 is indirectly cooled by circulating the cool air generated in the cooler 17 by the operation of the compressor motor 30 through the air flow path 15 in the heat insulation box 11 by the circulation fan 19. By cooling to. As a result, it is possible to prevent the food contained in the food container 14 from being excessively dried.

The inside of the refrigerator is cooled by the above cooling operation,
When the temperature falls below the refrigerating lower limit temperature TRL set for refrigeration, the refrigerating temperature switch Th1 opens, so that the compressor motor 30 is cut off and the cooling operation is interrupted. The circulation fan 19 is continuously operated even when the cooling operation is interrupted (see FIG. 3). Now,
To thaw the frozen food, the frozen food is stored in the food storage chamber 14
After setting the time to execute the defrosting operation in the defrosting timer TM2, the defrosting start switch 32 is turned on (time t1 in FIG. 3). Then, the relay coil X2 is energized to be in a self-holding state, and the fan 22 and the timer motor 34 of the thawing timer TM2 are energized to start the air circulation in the food storage chamber 14 and the thawing timer TM2 is timed. Is started. Then, since the normally closed relay contact x2 is opened and the normally open relay contact x2 is closed, the compressor motor 30 leaves the control by the refrigeration temperature switch Th1 and shifts to the control by the defrosting temperature switch Th2, and the heater 20 is energized. It becomes possible to enter the decompression mode.

Immediately after shifting from the refrigerating mode, the temperature inside the refrigerator is low, and the thawing temperature switch Th2 is switched to the heater 20 side, so that the heater 20 is energized and the cooler 17 is heated. As a result, the air flow path 15 outside the inner box 12
Since the hot air is circulated in the interior, the temperature in the food storage chamber 14 rises, the frozen food is gently heated, and the thawing progresses gradually. By the way, when a large amount of frozen food is stored in the food storage chamber 14, the so-called cold heat amount is large, and therefore the internal temperature of the refrigerator tends to decrease. There is a case where the internal temperature of the refrigerator tends to increase due to heat entering from the outside and self-heating of the internal fan 22. In such a case, in the present embodiment, when the temperature in the food storage chamber 14 exceeds the thawing upper limit temperature TDH, the thawing temperature switch Th2 is switched to the compressor motor 30 side, so that the heater 20 is cut off (for heating operation). In addition, the compressor motor 30 is energized and the cooling operation is started. This is food storage room 1
Since the inside of 4 is cooled, excessive temperature rise is suppressed, and quality deterioration such as drip increase from frozen food is prevented. When the temperature inside the refrigerator decreases due to the cooling operation, when the lower limit temperature TDL for thawing is reached, the heater 20 is energized again to heat the inside of the refrigerator, and this is repeated thereafter for thawing the inside of the food storage chamber 14. It will be maintained at the set temperature. This thawing operation is executed until the time measured by the thawing timer TM2 ends, and when the time set in the timer has elapsed (time t2 in FIG. 3), the timer switch 33 opens and the thawing operation ends.

(Effects of Embodiment) As described above, according to this embodiment, even if the temperature in the food storage chamber 14 tends to rise when the amount of frozen food stored is small, the temperature of the frozen food tends to rise. When the temperature exceeds the thawing upper limit temperature TDH, the cooling operation is started. As a result, an excessive temperature rise in the food storage chamber 14 is suppressed, so that it is possible to reliably prevent the quality deterioration such that the temperature of the frozen food rises more than necessary and the drip from the frozen food increases. it can. <Second Embodiment> Next, a second embodiment of the present invention will be described with reference to FIGS. This embodiment corresponds to the invention of claim 2 which embodies the control method of the defroster according to claim 4, and the mechanical structure of the defroster is the same as that of the first embodiment, and its operation control device is Be different. Therefore, with respect to the mechanical structure, the description of the first embodiment is cited and the duplicated description will be omitted. Regarding the operation control device, only the parts different from the first embodiment of FIG. 2 will be described with reference to FIG. 4.

The thawing temperature switch Th2 is a normally open relay contact x which is of a two-circuit switching type as in the first embodiment.
The relay coil X3 or the heater 20 can be selectively energized via 2. This thawing temperature switch T
h2 is the thawing lower limit temperature T set in the food storage chamber 14
Below DL, enable the energization path on the heater 20 side,
When the thawing upper limit temperature TDH is reached, the energizing path on the side of the relay coil X3 is activated, and the refrigerating lower limit temperature TRL and the refrigerating upper limit temperature TRH are set.
The relationship with is similar to the first embodiment in that the relationship of TRL <THH <TDL <TDH is set. The normally open relay contact x3 is provided in the energizing path to the compressor motor 30 so as to bypass the refrigerating temperature switch Th1, so that the compressor motor 30 can be operated when the relay coil X3 is energized. Has become.

On the other hand, the defrosting timer TM2 is provided with a clutch mechanism (not shown) in this embodiment, and the clutch coil 4 thereof is provided.
The timekeeping operation is performed only while 1 is energized. The clutch coil 41 is connected to the power supply line via the normally open relay contact x2, and the relay coil X2 is connected to the power supply line via the timer switch 43 and the normally open relay contact x2. The timer motor 42 is connected to the power supply line via the normally open relay contact x3, and the heater 2
When the power is 0 (when the heating operation is suppressed), that is, when the compressor motor 30 is energized, the timer motor 42 is energized to perform the timing operation.

According to the configuration of this embodiment, when the defrosting start switch 32 is turned on, the defrosting operation is started in the same manner as in the first embodiment, and the heater 20 (compressor motor 30 if necessary) is energized to turn on the food. The inside of the storage chamber 14 is maintained between the thawing lower limit temperature TDL and the thawing upper limit temperature TDH. At this time, the defrosting timer TM2 does not always perform the time counting operation while executing the defrosting operation, but when the heater 20 is cut off (when the heating operation is suppressed), that is, when the compressor motor 30 is energized ( Timer motor 4 only during cooling operation)
2 is energized to perform a time counting operation, and the time is integrated. Then, when the integrated value reaches the set value, the timer switch 43 is opened and the relay coil X2 is cut off, so that the thawing operation ends (time t2 in FIG. 5).

Here, when a large amount of frozen food is stored in the food storage chamber 14, since the so-called cold heat amount is large, it takes a long time to rise to the upper limit temperature (temperature change as shown in FIG. 8). Rate is small), and then falls to the lower limit temperature in a short time (the temperature change rate is large). On the contrary, when the amount of frozen food contained is small, it rises to the upper limit temperature in a short time as shown in FIG. (High temperature change rate), the temperature reaches the lower limit temperature slowly (low temperature change rate). Therefore, in this embodiment, when a large amount of frozen food is stored in the food storage chamber 14, the energization time to the compressor motor 30 is shortened, and the progress of time integration by the timer motor 42 is delayed. Become. Therefore, it takes a long time to measure the set time, and eventually the time for which the thawing operation is executed becomes long, which is suitable for thawing a large amount of frozen food. On the contrary, when the amount of frozen food stored in the food storage chamber 14 is small, the heater 20 is cut off, that is, the cooling operation is executed for a long time. Will be faster. For this reason, the set time is integrated in a short time, and eventually the time during which the thawing operation is executed is shortened, which means that the amount of frozen food is small.

Therefore, according to the present embodiment, the decompression timer T
Even if the set time of M2 is not adjusted according to the amount of frozen food, the thawing operation of the length corresponding to the amount is naturally executed, and the troublesome operation of adjusting the set time of the thawing timer is unnecessary. In addition to the above, there is an advantage that a proper thawing quality can always be obtained. Of course, if the temperature in the food storage chamber 14 tends to rise during the execution of the thawing operation, the compressor motor 30 is energized to execute the cooling operation, so the temperature of the frozen food rises more than necessary and the frozen food As in the first embodiment, it is possible to surely prevent the quality deterioration such as the increase in the drip from.

<Third Embodiment> FIGS. 6 and 7 show a third embodiment of the present invention. This third embodiment corresponds to the invention of claim 3 which embodies the control method of the defrosting store according to claim 4,
The mechanical structure of the thawing refrigerator is the same as that of the first embodiment, but the operation control device is different. Therefore, here also, regarding the mechanical structure, the description of the first embodiment is cited and the overlapping description is omitted, and regarding the operation control device, only the points different from the first embodiment of FIG. 2 will be described with reference to FIG. To do. In this embodiment, as the thawing chamber temperature detecting means, first and second thawing temperature switches T having different set temperatures are set.
h2 and Th3 are provided, and the upper limit temperature for suppressing execution of the heating operation can be changed by selectively activating either one. First thawing temperature switch Th2
Is a two-circuit switching type similar to the first and second embodiments, so that the relay coil X3 or the heater 20 can be selectively energized via the normally open relay contact x2 and the normally closed relay contact x4 in series. And the second thawing temperature switch T
The h3 is also of a two-circuit switching type and can selectively energize the relay coil X3 or the heater 20 through the normally open relay contact x2 and the normally open relay contact x4 in series. Both of the thawing temperature switches Th2 and Th3 activate the energization path on the heater 20 side below the set thawing lower limit temperature in the food storage chamber 14 and turn on the relay coil X3 side energization path when the thawing upper limit temperature is reached. The point that it is made effective is the same as in the second embodiment, but the lower thaw temperature TDL3 of the thaw temperature switch Th3 is the thaw temperature switch Th.
The temperature is set higher than the lowering temperature TDL2 of No. 2 of thawing. Further, the relationship between the set temperatures including the lower limit temperature of refrigeration TRL and the upper limit temperature of refrigeration TRH is TRL <TRH <TDL2 <TDH2 <TDL3
<TDH3.

The normally open relay contact x3 is provided in the energizing path to the compressor motor 30 so as to bypass the refrigerating temperature switch Th1 as in the second embodiment, whereby the compressor motor is energized when the relay coil X3 is energized. Thirty
You can drive. On the other hand, as for the defrosting timer, in this embodiment, two first and second defrosting timers TM2 and TM3 are provided, each of which is provided with a clutch mechanism (not shown) as in the second embodiment, and each clutch coil 51, The time keeping operation is performed only while the current is supplied to the clutch coils 51, 51.
Is connected to the power supply line via a normally open relay contact x2. The relay coil X2 is connected to the power line via the timer switch 53 of the first defrosting timer TM2 and the normally open relay contact x2, and the relay coil X4 is a normally open type timer switch of the second defrosting timer TM3. It is connected to the power supply line via 53. Then, the timer motor 52 of the first defrosting timer TM2 has the normally open relay contact x
3, connected to the power supply line via the normally open relay contact x4 and the timer switch 53, and the timer motor 52 of the second defrosting timer TM3 is connected to the power supply line via the normally open relay contact x3 and the timer switch 53. .

According to the configuration of this embodiment, when the defrosting start switch 32 is turned on (time t1 in FIG. 7), the defrosting operation is started in the same manner as in the first embodiment, and the heater 20 (the compressor motor 30 if necessary) is started. ) Is energized to food storage room 1
The temperature inside 4 is first maintained between the lower thaw temperature TDL2 and the upper thaw temperature TDH2 of the first thaw temperature switch Th2. When executing this defrosting operation, the first defrosting timer TM
2 performs the time counting operation, but like the second embodiment, the thaw timer TM2 does not always perform the time counting operation during the execution of the thaw operation, but when the heater 20 is turned off (heating). (When operation is suppressed), that is, compressor motor 3
Only when 0 is energized (during cooling operation), the timer motor 52 is energized to perform the time counting operation, and the time is integrated. Then, first, in the second defrosting timer TM3, the integrated value reaches the set value, the normally closed timer switch 53 opens, and the operation of the timer motor 52 stops (at time t2 in FIG. 7). The open type timer switch 53 is closed and the relay coil X4 is energized. As a result, the normally-open relay contact x4 is closed to allow the second defrosting timer TM3 to perform the timekeeping operation and the second defrosting temperature switch Th3.
The temperature control is started by and the upper limit temperature is set high.

That is, as shown in FIG. 7, the food storage chamber 1
The temperature inside 4 is maintained between the lower thaw temperature TDL3 and the upper thaw temperature TDH3 of the second thaw temperature switch Th3, and the frozen food is thawed at a higher temperature. At the time of executing this defrosting operation, the second defrosting timer TM3 is used.
However, the timing operation is performed only when the heater 20 is cut off (when the heating operation is suppressed), that is, when the compressor motor 30 is energized (when the cooling operation is performed), and the time is integrated. Then, when the integrated value of the first defrosting timer TM2 reaches the set value, the normally closed timer switch 53 is opened and the relay coil X2 is cut off, thereby ending the defrosting operation (FIG. 7). Time t3).

Here, as described above, when a large amount of frozen food is stored in the food storage chamber 14, it takes a long time because the so-called cold heat amount is large, the temperature rises to the upper limit temperature, and it takes a short time. When the amount of frozen food contained is small, the temperature lowers to the lower limit and rises to the upper limit in a short time and then slowly reaches the lower limit. Therefore, in this embodiment, when a large amount of frozen food is stored in the food storage chamber 14, the energization time to the compressor motor 30 is shortened, and the progress of time integration by each timer motor 52 is delayed. become. Therefore, since it takes a long time to measure the set time of the second defrosting timer TM3, the time until the defrosting operation is switched to a high upper limit temperature becomes long and the set time of the first defrosting timer TM2 is set. Since it takes a long time to measure the time, after all, the time for which the thawing operation is executed becomes long, and it is suitable for thawing a large amount of frozen food as a whole. On the contrary, when the amount of frozen food stored in the food storage chamber 14 is small, the heater 20 is cut off, that is, the cooling operation is executed for a long time. The progress of time integration by 52 is accelerated, and the set time is integrated in a short time. For this reason, the time until the temperature in the food storage chamber 14 is raised is shortened, and the time during which the thawing operation is performed is shortened, which is suitable for the small amount of frozen food.

Therefore, according to the present embodiment, like the second embodiment, even if the set time of the thawing timer TM2 is not adjusted according to the amount of frozen food, the thawing of the length corresponding to that amount is naturally performed. Since the operation is executed, the troublesome operation of adjusting the set time of the thawing timer is not necessary, and an advantage that an appropriate thawing quality can always be obtained is obtained. Moreover, since the upper limit temperature in the food storage chamber 14 is changed to a higher value during the thawing operation, unlike the thawing operation in which the upper limit temperature is set high from the beginning, the drip may increase and the quality may deteriorate. In addition, thawing can be performed more quickly than in the thawing operation in which the upper limit temperature is kept low until the end. Of course, if the temperature in the food storage chamber 14 tends to rise during the execution of the thawing operation, the compressor motor 30 is energized and the cooling operation is executed,
Similar to the first embodiment, it is possible to reliably prevent the quality deterioration such that the temperature of the frozen food is increased more than necessary and the drip from the frozen food is increased.

<Other Embodiments> The present invention is not limited to the above embodiments, and the following embodiments are possible, for example, and these are also included in the technical scope of the present invention. (1) In each of the embodiments, the resistance heating type heater 20 is provided as the heating device, but instead of this, the cooler 17 is provided.
It is also possible to employ a heat pump type heating method in which a high-pressure and high-temperature compressed refrigerant is flowed. Further, the control method of the heating device is not limited to completely disconnecting the heater, and the heat generation amount may be suppressed to be low. (2) In each of the embodiments, an example in which the invention is applied to a thawing refrigerator is shown, but the invention is not limited to this, and the invention can also be applied to a thawing warehouse dedicated to thawing, and particularly to carry out the inventions of claims 2 to 4. Alternatively, it may be applied to a thawing cabinet provided with only a heating device without a cooling device.

(3) In the second and third embodiments, the thaw operation is controlled on the basis of the temperature change rate during the cooling so that the time measurement operation of the timer is performed when the thaw chamber is cooled to change the execution time of the thaw operation. However, conversely, it is possible to adopt a configuration in which the thawing operation is controlled based on the rate of temperature change during heating of the thawing chamber. In addition, the invention of the present application is not limited to the embodiments described by the above description and the drawings, and various modifications may be made without departing from the scope of the invention.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional view of a thawing refrigerator showing a first embodiment of the present invention.

FIG. 2 is an electric circuit diagram of the operation control device.

FIG. 3 is a graph showing the temperature change during the thawing operation as well.

FIG. 4 is an electric circuit diagram of an operation control device showing a second embodiment.

FIG. 5 is a graph showing a temperature change during the thawing operation as well.

FIG. 6 is an electric circuit diagram of an operation control device showing a third embodiment.

FIG. 7 is a graph showing the temperature change during the thawing operation as well.

FIG. 8 is a graph showing temperature changes when the amount of frozen food is large.

FIG. 9 is a graph showing a temperature change when the amount of frozen food is small.

[Explanation of symbols]

11 ... Insulation box body 14 ... Food storage room (defrosting room) 17 ...
Cooler (cooling device) 20 ... Heater (heating device)

Claims (4)

[Claims] 1. A heat-insulating box forming a thawing chamber for storing frozen food, a temperature detecting means for detecting a temperature inside the thawing chamber, a heating device for heating the thawing chamber, and the inside of the thawing chamber. A cooling device for cooling, and an operation control device for controlling the operation of the cooling device and the heating device in order to maintain the temperature at the set temperature for thawing according to the temperature in the thawing chamber detected by the internal temperature detecting means. A defroster equipped with. 2. An adiabatic box which constitutes a defrosting chamber for storing frozen foods, an in-compartment temperature detecting means for detecting the temperature in the defrosting chamber, a heating device for heating the defrosting chamber, and the in-compartment temperature. And a operation control device for suppressing the execution of the heating operation when the temperature in the defrosting chamber detected by the detection means decreases to a predetermined lower limit temperature and the heating operation is performed by the heating device and rises to a predetermined upper limit temperature. The operation control device has a timer for accumulating the time during which the heating operation is suppressed, and the thaw operation is terminated on the condition that the time accumulated by the timer reaches the set time. Characteristic defroster. 3. A heat-insulating box that constitutes a defrosting chamber for storing frozen foods, a chamber temperature detecting means for detecting a temperature in the defrosting chamber, a heating device for heating the defrosting chamber, and a chamber temperature. When the temperature in the defrosting chamber detected by the detection means decreases to a predetermined lower limit temperature, a heating operation is performed by the heating device, and when the temperature rises to a predetermined upper limit temperature, an operation control device that suppresses the execution of the heating operation is provided. The operation controller is
It has a timer for integrating a time during which the heating operation is suppressed, and is configured to change the upper limit temperature to a high value on the condition that the time integrated by the timer reaches a predetermined time. Warehouse. 4. A heat-insulating box that constitutes a defrosting chamber for storing frozen foods, an in-compartment temperature detecting means that detects the temperature in the defrosting chamber, a heating device that heats the defrosting chamber, and the in-compartment temperature. In a defroster equipped with an operation control device that activates the heating operation by the heating device when the temperature in the thawing chamber detected by the detection means decreases to a predetermined lower limit temperature and suppresses the heating operation when the temperature rises to a predetermined upper limit temperature A thawing operation control method, wherein the thawing operation is controlled based on a temperature change rate in the thawing chamber when the heating operation is performed or when the heating operation is suppressed.