JPH0445379A - Refrigerator with defreezing chamber - Google Patents

Abstract

PURPOSE:To enable a defreezing operation without temperature unevenness at each of a central part and a surface part within a short period of time and further to keep freshness at a temperature suitable for a fish or a meat upon completion of the defreezing operation by a method wherein a double-surface heating with a far infrared ray radiation heating from an upper surface and a thermal transmitting heating from a bottom surface is carried out and a heating capacity of both heaters is decreased in a stepwise manner during a defreezing operation. CONSTITUTION:A defreezing control device has a defreezing time divided into three stages. A far infrared ray heater 27 and a heating heater 32 are continuously energized by an electrical energization with a time until the temperature of the first temperature sensor 33 is increased up to a predetermined temperature being applied as the first stage. Subsequently, the electrical energization for both heaters is intermittently carried out toward the second and third stages. At the first and second stages, a damper thermostat 13 is forcedly released and at the third stage, the damper thermostat 13 is forcedly closed. During a non-defreezing operation, a temperature in the second temperature sensor 24 disposed in a defreezing chamber 8 causes the damper thermostat to be opened or closed in response to the first predetermined temperature and further causes a temperature in the defreezing chamber to be kept at the third temperature range between a refrigeration temperature and a freezing temperature. As a temperature of the second temperature sensor 24 becomes the second predetermined temperature higher than the first predetermined temperature, it is controlled such that an electrical energization for both heaters is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a refrigerator with a thawing chamber for thawing frozen foods.

BACKGROUND OF THE INVENTION Examples of using a heater to defrost frozen foods have been known for some time. For example, an example is shown in Japanese Utility Model Publication No. 48-25414, and will be explained below with reference to FIGS. 7 and 8. do.

Reference numeral 80 denotes a thawing box, which includes an outer box 81 made of metal or synthetic resin, etc., and a metal box 81 made of metal such as aluminum with good thermal conductivity, which is provided with an appropriate gap inside the outer box 81. It is composed of an inner box 82. Reference numeral 83 denotes a linear heater, which is closely connected to the inner box 82 through aluminum foil 84 so that the bottom surface of the thawing box 80 is sparse and the top surface is densely packed. 85 is a heat insulating material, which includes the outer box 81 and aluminum foil 84.
It is interposed in between. 86 indicates the food to be thawed.

In the above configuration, when the food to be thawed 86 is placed on the bottom surface of the thawing box 80 and the thawing action is started, heat is applied from the entire circumference of the inner box 82 by the heating of the heater 83.
The food to be thawed 86 can be heated and thawed more or less uniformly.

Problems to be Solved by the Invention However, with the above configuration, heat is transmitted from the bottom of the thawing box 80 to the bottom of the food to be thawed 86 by heat conduction, and although it is possible to thaw the bottom of the food 86, the thawing box 80 The effect of radiant heat on the food to be thawed 86 from the top and side surfaces is almost negligible because the heat ray wavelength from the heater 83 through the inner box 82 is in the near-infrared region of 5 μm or less. Heating occurs only by convective heat transfer of warmed air. For this reason, there are problems in that the thawing unevenness between the center and surface of the food to be thawed 86 tends to become large, and the thawing time also takes a long time. Since deterioration occurs due to the high ambient temperature, it is necessary for the user to monitor the completion of defrosting, and there is a problem that the product cannot be used with confidence.

The present invention solves the above-mentioned problems, and aims to provide a thawing chamber, especially in a refrigerator, that is less uneven in thawing and can be thawed in a short time.

Means for Solving Problems In order to achieve the above object, the present invention provides a freezer compartment, a refrigerator compartment, a thawing compartment whose outer periphery is surrounded by a heat insulating material and a front opening provided with a door that can be opened and closed, and a compression compartment. a refrigeration cycle having a refrigerator, a cooler, etc., and a blower for forcing air cooled by the cooler into the freezing compartment, refrigerator compartment, and thawing compartment, respectively;
a far-infrared heater provided in the upper part of the thawing chamber; a heating heater that is in close contact with the back surface of the metal bottom plate in a thermally conductive manner; and a first heater that is in close contact with the back surface of the bottom plate in a thermally conductive manner. a temperature sensor, a metal reflecting plate that covers the upper surface of the far-infrared heater in a dome shape, and a thawing dish that is heat-conductive and removably installed on the bottom plate on which food to be thawed is placed. and,
a damper thermometer installed at the entrance of the thawing chamber to adjust the amount of cold air inflow by electrical input; a ventilation passage communicating with the damper thermometer and formed in a space above the back surface of the reflector; The defrosting control device includes a large number of ventilation holes that communicate the ventilation passage with the inside of the thawing chamber, and a thawing control device that forces the blower to operate during thawing and controls the thawing time, and the thawing control device divides the thawing time into three stages. The far-infrared heater and the heating heater are continuously energized as a first stage from the start of thawing until the temperature of the first temperature sensor rises to a predetermined temperature, and thereafter, second and third stages In the first and second stages, the damper thermo is forcibly opened, and in the third stage, the damper thermo is forcibly closed. and when not defrosting, the temperature of the second temperature sensor provided in the defrosting chamber is set to a first predetermined temperature to open and close the damper thermo, and the temperature in the defrosting chamber is adjusted to a temperature between the refrigerating temperature and the freezing temperature. Refrigerator with a defrosting chamber controlled to maintain the temperature in the temperature range No. 3 and to stop supplying electricity to both heaters when the temperature of the second temperature sensor reaches a second predetermined temperature higher than the first predetermined temperature. And so.

Function The present invention is configured such that the thawing is controlled by the thawing control device as described above. That is, far-infrared rays are directly radiated by the far-infrared heater and indirectly radiated through the reflector from the top and side surfaces of the food to be thawed, and heat is absorbed by conductive heating from the bottom heater. or,
In the first stage where the first temperature sensor on the bottom rises to a predetermined temperature, both heaters are continuously energized and the temperature of the food to be thawed rises rapidly. After that, the intermittent energization rate to both heaters is the second
．． In the third stage, the temperature decreases step by step, and in the first and second stages, cold air is evenly supplied to the food to be thawed through the many ventilation holes formed on the top surface of the reflector through the damper thermo. It is designed to suppress the rise in surface temperature.

In the third stage, the damper thermo is blocked and the waste heat in the thawing chamber is not recovered to the cooler side.Also, if you accidentally start thawing without putting the food to be thawed, the temperature of the second temperature sensor When the temperature reaches a second predetermined temperature higher than the first predetermined temperature, power supply to both heaters is stopped to prevent each part from becoming abnormally high temperature. Furthermore, after thawing is completed, the temperature of the second temperature sensor is adjusted to the first predetermined temperature, and the food temperature is automatically adjusted to the third temperature range between the refrigeration temperature and the freezing temperature by the temperature control action by opening and closing the damper thermometer. It is kept cool and kept cool.

Embodiment 1 A refrigerator with a defrosting chamber, which is an embodiment of the present invention, will be described with reference to FIGS. 1 to 6.

In FIG. 1, l is the refrigerator main body, an outer box 2, an inner box 3, and a heat insulating material 4 filled between the outer box 2 and the inner box 3.
It is made up of. Reference numeral 5 denotes a partition wall, which divides the inside of the refrigerator main body l into upper and lower parts.
, a refrigerating chamber 7 is formed in the lower part. Reference numeral 8 denotes a thawing chamber, which is provided in an upper section of the refrigerator chamber 7. 9 is a compressor;
It is provided at the rear of the bottom of the refrigerator main body l. Reference numeral 10 denotes a cooler, which is housed in the back of the freezer compartment 6 and forms a refrigeration cycle together with the compressor 9.

Reference numeral 11 denotes a blower which blows cold air cooled by the cooler 10 into the freezer compartment 6. Forced ventilation is provided in the refrigerator compartment 7 and the thawing compartment 8. lz, 13 is a damper thermostat, which is installed at the entrance of the refrigerator compartment 6 and thawing compartment 8 to adjust the amount of cold air flowing in by electrical input. This will be explained with reference to FIG. 14 is an electromagnetic coil, 15 is a plunger, and the electromagnetic coil! The inner center of 4 moves up and down depending on the presence or absence of electromagnetic action. A rod 16 is connected to the plunger 15. 17 is a damper, which opens and closes the cold air passage. When the electromagnetic coil is energized, the rod 16 is pushed up by electromagnetic action and the damper 17 is opened, and when the energization is cut off, the rod 15 falls downward and the damper 17 is closed. is configured to do so. Note that the damper thermostat 12 for the refrigerator compartment also has a similar configuration.

Returning to FIG. 1, 18 and 19 are discharge ducts that direct cold air from the blower 11 to the refrigerator compartment 7. Lead to thawing chamber 8<,
Reference numerals 20 and 21 indicate suction ducts, which are ducts for returning cold air that has cooled the insides of the refrigerator compartment 7 and the thawing compartment 8 to the cooler IO. Further, 2Z and 23 are temperature detectors, which detect the temperatures of the freezing compartment 6 and the refrigerator compartment 7, respectively. Also, 24
is a second temperature sensor that detects the temperature inside the thawing chamber 8.

Next, details of the thawing chamber 8 will be explained according to FIGS. 3 and 4.

25 is an outer box made of synthetic resin; 26 is a heat insulating material;
It is installed on the inner surface of 5 and surrounds the outer periphery. 27
is a far-infrared heater, which is installed in the upper part of the thawing chamber 8, and is effective at far-infrared rays of about 5 μm or more by baking a ceramic paint layer mainly composed of silicon or the like on the surface of a glass tube in which a heater wire is enclosed. It is configured to radiate. This far-infrared heater 27 is suspended and supported by a dome-shaped reflector plate 29 made of metal such as aluminum through a holder 28 made of synthetic resin with high heat resistance. Further, the reflecting plate 29 is also integrally formed with the inner box portions that constitute the both side walls and the back wall of the thawing chamber 8, and furthermore, a large number of ventilation holes 30 are formed in the flat portions on both sides of the top dome portion. Next, 31 is the bottom plate, which is made of metal such as aluminum, and 32
is a heater, which is fixed to the back surface of the bottom plate 31 with aluminum foil or the like in a thermally conductive manner, and has a linear shape.

Reference numeral 33 denotes a first temperature sensor, which is brought into close contact near the center of the back surface of the bottom plate 31 for thermal conduction. 34 is a thawing dish,
The food to be thawed 3 is removably installed on the bottom plate 31.
It is composed of a plate 36 made of metal such as aluminum on which 5 is placed, and a frame 37 made of synthetic resin surrounding the outer periphery. 38
A protective net is fixedly installed below the reflecting plate 29 at a constant interval to prevent burns. 39 is a door that opens and closes the front opening of the thawing chamber 8. Also, 40
is a ventilation passage formed in the space on the back surface of the reflector plate 29, and is connected to the damper thermo! via the discharge port 41. It is connected to 3. A suction port 42 is formed on the back wall of the thawing chamber 8 and communicates with the suction duct 21 .

In FIG. 1, 43 is a defrost switch, which is provided on the front surface of the outer shell of the refrigerator main body l.

Next, the electric circuit and control circuit will be explained with reference to FIGS. 5 and 6.

In FIG. 5, the compressor 9 is connected via a relay contact 44 to
The blowers II are each connected to a power source via a relay contact 45. The far-infrared heater 27 is connected to a power source via a relay contact 46, and the heating heater 32 is connected to a power source via a relay contact 47. Also, the electromagnetic coil 14 of the damper thermo for the thawing chamber. The damper coils +4' for the refrigerator compartment are each connected to the power supply via relay contacts 48,49.

Reference numeral 50 denotes a freezer temperature control device, which includes a temperature detector 22 such as a thermistor, resistors Rl, R*, Rs, a comparator circuit including a comparator 51, and a transistor 52. It is equipped with a relay coil 53, and the comparator 5! The output of is connected to the base of the transistor 52. Further, the collector of the transistor 52 is connected to the relay coil 53 for attraction, which opens and closes the relay contact 44 . 54
is a refrigerator room temperature control device, which includes a temperature sensor 2 such as a thermistor.
3. Comparison circuit with resistor R, RI, R@, comparator 55, transistor 56. A relay coil 57 is provided, and the output of the comparator 55 is connected to the base of the transistor 56. Also, transistor 5
The relay coil 57 for suction, which opens and closes the relay contact 49, is connected to the collector 6. 58 is a control device for the thawing chamber temperature II and a second temperature sensor 24, such as a thermistor. Resistance Rt, Ra, R1, comparator 5
9 and resistance R+s, RI4, Rts, comparator 59
It is equipped with two comparison circuits equipped with a, an OR circuit 60, an AND circuit 60a, a transistor 61, and a relay coil 62, and during normal cooling, the temperature inside the thawing chamber 8 is controlled to a partial freezing temperature of about -3°C. The resistor is configured to The output of the comparator 59 is connected to one input of the OR circuit 60. The output of the OR circuit 60 is connected to the base of the transistor 61 via the AND circuit 60a, and the collector of the transistor 61 is connected to the relay coil 62 for attracting the relay contact 48.

63 is a thawing control device, which includes a first temperature sensor 33 closely attached to the bottom plate 31 of the thawing chamber 8, resistors R8°, R11,
Rlm, comparison circuit with comparator 64 and timer 65.66.67.67a, AND circuit 68.69.6
9a, OR circuit 70.7+, 72, inverter 73,
Inverter 73a, transistors 74, 75, 76, relay coils 77, 78, 79 and the defrosting switch 43
It is equipped with

The output of the defrosting switch 43 is the output of the timer 6.
5, and the output of the timer 65 is connected to the input of the A N D circuit 68, 69a, the OR circuit 6o, 72.
are connected to one input of each. The output of the comparator 64 is connected to the AN via the inverter 73.
It is connected to the other input of the D circuit 68 and simultaneously connected to one input of the AND circuit 69. The output of the comparator 59a is connected to the other input of the AND circuit 69a via the inverter 73a,
The output of this AND circuit 69a is connected to the other input of the AND circuit 69. The output of the AND circuit 68 is connected to one of the OR circuits 70 and 71a, and the output of the AND circuit 69 is connected to the timer 66, 67, 6.
It is connected to the input of 7a. and the timer 66
．． The outputs of 67 are connected to the other inputs of the OR circuits 70.71, and the outputs of the OR circuits 70.71 are connected to the bases of the transistors 74.75, respectively. The collector of the transistor 74.75 is connected to the relay coil 77.78 for attraction, which opens and closes the relay contact 46.47. The output of the timer 67a is connected together with the output of the OR circuit 60 to one input of the AND circuit 60a. Further, the output of the comparator 51 of the freezing room temperature control device 50 is connected to the other input of the OR circuit 72, and the output of the OR circuit 72 is connected to the base of the transistor 76. A suction relay coil 79 for opening and closing the relay contact 45 is connected to the collector of the transistor 76.

Incidentally, here, the timer 65 operates for a predetermined time t once the "old gh" (hereinafter simply referred to as "H") signal is input.
It is configured to continue outputting an H'-fold signal, and then switch to a "LO" signal (hereinafter simply referred to as "L").

In addition, the timers 66 and 67 alternately output "H" and "L" signals for a predetermined period of time while the "H° double signal is being input to the input, but after a predetermined period of time has elapsed, the intermittent output rate of the H" signal is reached. is configured to decrease in stages.

For example, specifically, the output rate of the timer 66 is 80% for the first time 1+, and 80% for the next time t.
1, the output rate of the "H" signal is 40%, and the output of the timer 67 is "H°" for the first time "1+".
The structure is such that the double signal output rate is 80% and the "H" signal output rate is 0% at the next time t'. Incidentally, the operating time of the timer 65.67 is tr +tm =t+
'+tm, and the predetermined time t of the timer 65 is the operating time tI+t of the timer 66 and 67, including the time-safe role of the defrosting action.
It is set to be sufficiently longer than s=tt''+jt'.

Further, the output of the timer 67a is normally "H", and when "H" is input to the input of -1, the time tr = j
The output of r' continues "Ho, then time ts"
Lm" is connected so that the output becomes "L".

In the above configuration, when the temperature of the freezer compartment 6 is higher than a predetermined value, the resistance value of the temperature detector 22 is small and the output of the humpator 51 becomes "H", so the transistor 52 becomes ONL and the relay is activated. Coil 53 becomes conductive.

Therefore, the relay contact 44 is closed and the compressor 9 is operated. At the same time, the output of the OR circuit 72 also becomes "H", so the transistor 76 turns ON, and the relay coil 79 becomes conductive. Therefore, the relay contact 45 is closed and the blower 11 is also operated to operate the freezer compartment 6, refrigerator compartment 7. Thawing chamber 8
Cooling is performed by forcing cold air into the freezer compartment 6.
When the temperature sensor 22 is cooled down to a predetermined temperature, the resistance value of the temperature sensor 22 increases and the output of the comparator 51 becomes "L".
Therefore, the transistor 52 becomes 0FFL.

Since the output of the OR circuit 72 also becomes “L”, the transistor 7
6 is also 0FFL, and the power to the relay coil 53.79 is cut off. Therefore, both relay contacts 44 and 45 are connected to the compressor 9. The blower If stops. Thereafter, this action is repeated to maintain the temperature inside the freezer compartment 6 at a predetermined temperature (for example, -20°C).

Next, when the temperature of the refrigerator compartment 7 is higher than a predetermined value, the resistance value of the temperature detector 23 is small, and the comparator 55
Since the output of becomes “H”, the transistor 56 becomes ONL,
The relay coil 57 becomes conductive. Therefore, relay contact 4
9 is closed, the electromagnetic coil 14' is energized, the damper 17 of the damper thermometer 12 is opened, and cold air is introduced into the refrigerator compartment 7 to perform a cooling effect.The refrigerator compartment 7 is then cooled to a predetermined temperature. If so, the resistance value of the temperature sensor 23 becomes large and the output of the comparator 55 becomes "L". Therefore, the transistor 56 is turned off, the current to the relay coil 57 is cut off, and the relay contact 49 is opened. Power to the electromagnetic coil +4' is also cut off. Then, the damper 17 of the damper thermostat 12 is closed to prevent cold air from flowing into the refrigerator compartment 7. Thereafter, this action is repeated to maintain the temperature inside the refrigerator compartment 7 at a predetermined temperature (for example, 5° C.).

In addition, when the temperature of the thawing chamber 8 is higher than a predetermined value during non-defrosting, the resistance value of the second temperature detector 24 is small and the output of the comparator 59 becomes "H", so the OR circuit 60, the output of the AND circuit 60a becomes "H", and the transistor 61 becomes ONL.

The relay coil 62 becomes conductive. Therefore, relay contact 4
8 is closed, the electromagnetic coil 14 is energized, the damper 17 of the damper thermometer 13 is opened, and cold air is introduced into the thawing chamber 8 to perform a cooling effect.Then, the thawing chamber 8 is cooled to a predetermined temperature. In this case, the resistance value of the second temperature sensor 24 increases and the output of the comparator 5g becomes "L".
Therefore, the output of the OR circuit 60 becomes "L", the output of the AND circuit 60a also becomes "L", and the transistor 61 is turned off.
F, the power supply to the relay coil 62 is cut off, the relay contact 48 is opened, and the power supply to the electromagnetic coil 14 is also cut off. And damper thermo! The damper 17 of No. 3 is closed to prevent cold air from flowing into the thawing chamber 8. Thereafter, by repeating this action, the temperature inside the thawing chamber 8 is controlled to the third temperature zone between the freezing temperature and the refrigeration temperature suitable for preserving fresh foods, that is, the partial freezing temperature zone of approximately -3°C, as described above. maintained.

Next, we will discuss the action during thawing. First, the food to be thawed 35 to be thawed is placed on the thawing tray 34 and placed on the bottom plate 31 in the thawing chamber 8, and then the thawing switch 43 is turned on.
Insert. At the same time as the input, the timer 65 starts outputting an "H" signal, and one input of the AND circuit 68, 69a becomes "H". For example, -20° C.) The temperature decreases due to heat conduction of the thawing tray 34 on which the food 35 to be thawed is placed. That is, the first temperature sensor 33 is in a sufficiently low temperature state. Therefore, the outputs of the comparators 64 and 64a are both "Lo", and the outputs of the inverters 73 and 73a are "Lo".
The signals, both of which are inverted to "H", are input to the other inputs of AND circuits 68 and 69a, respectively. Therefore, since both inputs of the AND circuit 69a become "H-", the output becomes "H" and is inputted to one input of the AND circuit 69.On the other hand, the AND circuit 69 has a "L" signal that does not go through the inverter 73. The signal is input as is. Therefore, A
Since the output of the ND circuit 68 is "H" and the output of the AND circuit 69 is "L", the timers 66 and 67 do not operate and the O
The outputs of the R circuits 70 and 71 become H", and the transistor 7
4.75 turns on. Then, the relay coils 77 and 78 are energized, the relay contacts 46 and 47 are closed, and the far-infrared heater 27 and the heating heater 32 are continuously energized. and,
When the thawing action progresses and the first temperature sensor 33 rises to a predetermined temperature (for example, 20° C.) (the time required for this is defined as to, and this period is defined as the first stage), the comparator 64 The output becomes “Ho” and the inverter 73
The “yes” signal is input to the AND circuit 68 through A
The output of the ND circuit 68 becomes "L", while the "H" signal is input to the AND circuit 69, so the timer 66.
67 begins to alternately repeat and output "H" and "L" signals at a predetermined intermittent output rate.Therefore, the transistors 74.75 and 74.75 start to output signals of "H" and "L" alternately and repeatedly at a predetermined intermittent output rate.
turns ON10FF.

Then, the relay coils 77, 78 are de-energized and the relay contacts 46, 47 are intermittently opened and closed. the result,
The far infrared heater 27 has an energization rate of 8 during the time 1+ (this period is defined as the second stage) following the continuous energization time t0.
0%, and the next time tm (this period is defined as the third stage), the energization rate is 40%, and the heat generation capacity is controlled to gradually decrease as time passes. Also, the heater 32
The time j+' following the continuous energization time t0 is the energization rate 8.
0%, and the next time tm' is controlled so that the energization rate is 0% and the heat generation capacity is decreased. In this way, in the early stage of thawing when the temperature of the food to be thawed 35 is low, both the far-infrared heater 27 and the heating heater 32 are continuously energized until the temperature of the first temperature sensor 33 rises to a predetermined temperature. Even if the weight of the first temperature sensor 33 varies, thawing can proceed rapidly under conditions with a large calorific value for a time suitable for each weight depending on the degree of temperature rise of the first temperature sensor 33. Therefore, the thawing time can be shortened. Thereafter, the heat generating capacity decreases stepwise with the passage of time, and thawing proceeds while suppressing the rise in surface temperature of the food 35 to be thawed.

During thawing, the food to be thawed 35 is uniformly heated by radiation from the far-infrared heater 27 from the top surface due to the reflection action of the reflector plate 29, and conductive heating by the heater 32 from the bottom surface. It will be done at the same time. Here, in the heating by the far infrared heater 27, far infrared rays with a long wavelength of 5 μm or more are radiated to the food to be thawed 35.
For general foods that have an absorption wavelength band in the far-infrared wavelength range, far-infrared rays are efficiently absorbed, and the far-infrared rays penetrate relatively deep into the food to be thawed 35, resulting in a relatively large temperature unevenness between the surface and the center. The thawing process continues without any problems. In addition, when heating with the heater 32, the bottom part of the food 35 to be thawed, which cannot be sufficiently heated by the two far-infrared heaters, is placed in the thawing tray 3.
It can be thawed by heat transfer heating through 4.

On the other hand, during the first, second and third stages in which the output of the timer 55 continues to generate an "H" signal during defrosting at the same time as the heating action of the far infrared heater 27 and the heating heater 32, the output of the OR circuit 72 becomes “H-” and transistor 7
6 is ONL, the relay coil 79 is conductive. Therefore, the relay contact 45 is closed and the blower (2) is forced to operate regardless of the output of the freezer temperature control device 50.

On the other hand, during this period, the output of the timer 67a is A, at which the output of the comparator 64 becomes "L" in the first stage.
The output of the ND circuit 69 is “L” due to the “Lo” output,
In the subsequent second stage, when the output of the AND circuit 49 changes to "H", the output of the timer 67a becomes "H" in the second stage and "L" in the third stage, so the output of the AND circuit 60a also changes. The first and second stages are "H", the third stage is "off", and the transistor 61 is turned ON, ON, and OFF during that period. In other words, during thawing, the damper thermometer 13 for the thawing chamber
The damper 14 of the first and second stages is forcibly opened,
The third stage is a pattern of forced occlusion.

In this way, the first and second stages are performed with the damper 1 open.
Cold air forcedly ventilated by the blower 11 passes through the discharge duct 19 through the discharge port 41 and flows into the ventilation passage 40 in the upper part of the thawing chamber 8 . The cold air flowing into the ventilation passage 40 is formed on the reflection plate 29 and is discharged downward through a large number of ventilation holes.
The surface of the food 35 to be thawed is uniformly cooled. Due to this action, the food to be thawed 35 is mainly affected by the far-infrared radiation effect of the far-infrared heater 27 and the control effect of gradually reducing the heat generation capacity of the far-infrared heater 27 and heating heater 32, as well as by further increasing the temperature of the surface area. As a result, thawing progresses with a small temperature difference between the center and surface areas and less uneven thawing. After the end of the second stage when the thawing has progressed considerably (for example, when the center temperature of the food 35 to be thawed is around 15° C.), the damper 14 of the damper thermostat 13 is forcibly closed and cold air is not introduced. In this state, the defrosting process gradually progresses while the amount of heat generated by the heater is small. During this time, the temperature of the food to be thawed 35 is also rising, so the heating efficiency of the heater and the heat absorption efficiency of the food to be thawed 35 are decreasing, but since the damper 14 is blocked, the temperature in the thawing chamber 8 is The residual heat is not recovered from the suction port 42 and is not returned to the cooler 10, so the amount of heat load on the cooler 10 is reduced accordingly.
Redundant operation of the compressor 9 is avoided. The temperature characteristics and time chart of the food 35 to be thawed during thawing are shown in FIG. 6.

In addition, regarding the thawing time, the internal penetration effect of far infrared rays and continuous heating control during the initial stage of thawing make it possible to thaw in a relatively short time (for example, about 30 minutes for a tuna weighing 500 g and 25 mm thick). Since the reflector plate 29 is exposed in the ventilation passage 40, the temperature of the surrounding members of the reflector plate 29 itself, which is originally quite high temperature, is cooled and lowered, which is advantageous in terms of safety.

As this thawing action progresses, the time jo+t++Lm
=jo +t+ '·+t*' That is, when the total time of the first, second, and third stages has elapsed, the timer 66.
When the output of 67 becomes "Lo," the timer 66 inputs the signal to the reset terminal of the timer 65, and the timer 55
The output of is also L°. Therefore, transistor 74.7
5 reaches 0FFL, the relay coils 77 and 78 are de-energized, the relay contacts 46 and 47 are opened, and the far-infrared heater 27 and the heating heater 32 are de-energized to complete defrosting. At the same time, one input of the OR circuit 72 becomes "Yes", so the blower! ! The forced operation status of is canceled. Further, since the output of the timer 67a returns to "Ho", the human power of one side of the AND circuit 60a becomes "11", and the forcedly closed state of the damper 17 of the damper thermometer 13 for the defrosting chamber is released.

After the thawing is completed, the temperature inside the thawing chamber 8 is controlled based on the temperature detected by the second temperature sensor 24, as in the case of normal cooling. For this reason, the food to be thawed 35 after thawing is immediately cooled to stabilize in the partial freezing temperature range of about -3°C, and the temperature does not rise further due to residual heat. Even if you leave the fish,
Because it is kept cool at a partial freezing temperature range of approximately -3℃, which is suitable for preserving perishables such as meat, the user can defrost with peace of mind without having to monitor the completion of defrosting and immediately dispose of it, unlike conventional methods. The food to be thawed 35 can be used at any time after thawing, making it extremely convenient to use.

Next, we will explain what happens when the temperature rises excessively, such as when thawing is started in an empty state. When the temperature of the second temperature sensor 24 continues to rise and exceeds the first set temperature (for example, -3°C) and reaches the second set temperature (for example, 40°C), the comparator 59a
The output becomes "H", and the signal inverted to "L" by the inverter 73a is input to one input of the AND circuit 6ja. Therefore, the output of the AND circuit 69a becomes "L" and A
It is input to one input of the ND circuit 69. Therefore, AND
Since the output of the circuit 69 becomes "L", the timers 66 and 67
does not operate, and "L" signals are input to one input of both OR circuits 70 and 71. On the other hand, since the AND circuit 68 continues to output the "L" signal, the OR circuit 70.
An "L" signal is also input to the other input of 71. Therefore, the outputs of the OR circuits 70, 71 are both "L", and the transistors 74, 75 are 0FFL, and the relay coils 77, 78 are de-energized, and the relay contacts 46, 47 are turned off.
is in an open state, and the far-infrared heater 27 and the heating heater 3
Power supply to 2 is stopped. Therefore, when the temperature rises excessively, both heaters are forcibly turned off, so that thermal deformation of various parts of the defrosting chamber 8 can be prevented.

Effects of the Invention As described above, the refrigerator with a defrosting chamber of the present invention provides the following effects.

(1) Efficient heating can be achieved from both sides: far-infrared radiant heating using a far-infrared heater from the top, and conductive heating using a heating heater from the bottom, and the heat generation capacity of both heaters gradually decreases during thawing. Combined with the effect of far infrared rays penetrating into the interior of the food to be thawed, thawing with less temperature unevenness between the center and surface becomes possible.

(2) Since the far-infrared heater and heating heater are continuously energized until the first temperature sensor installed on the bottom plate of the thawing chamber rises to a predetermined temperature, even if the weight of the food to be thawed changes, the Rapid heating can be performed using the maximum capacity heater for only a certain amount of time, making it possible to defrost food in a short time.

(3) During the first and second stages of thawing, the damper thermo for the thawing chamber is forcibly opened and the blower is forced to operate continuously to allow the food to be thawed to pass through the ventilation passage formed in the space on the back of the reflector. Since cold air is allowed to descend and flow into the food, the surface of the food to be thawed is uniformly cooled, temperature rise is further suppressed, and thawing with less unevenness can be achieved.

(4) During the third stage of defrosting, the damper thermometer is forcibly closed, so the residual heat in the defrosting chamber is not returned to the cooler and does not become a heat load, which can reduce the need for extra cooling operation of the compressor.

(5) During thawing, the reflector and other peripheral components, which would normally be at high temperatures, are exposed to the ventilation path and cooled, so the temperature decreases, which is advantageous from a safety perspective.

(6) Even if an abnormal temperature rise occurs during thawing, both heaters are forcibly turned off, so thermal deformation of various parts of the thawing chamber can be prevented, eliminating any safety problems.

(7) After thawing, the inside of the thawing chamber is kept cool in the third temperature range between the freezing room temperature and the refrigerator room temperature (for example, the partial freezing temperature range of approximately -3°C), so it is exposed to residual heat immediately after thawing. The temperature of the thawed food does not rise further, and even if it is left as is, its freshness is maintained at a temperature suitable for raw food such as fish meat, and the food can be used at any time.

[Brief explanation of the drawing]

Figure 1 is a vertical sectional view of a refrigerator with a thawing chamber, Figure 2 is an enlarged sectional view of a damper thermometer installed at the entrance of the thawing chamber, Figure 3 is a perspective view of the thawing chamber, and Figure 4 is a vertical sectional view of a refrigerator with a thawing chamber. A sectional view of the thawing chamber, FIG. 5 is an electric circuit and control circuit diagram of the present invention, FIG. 6 is a time chart during thawing and a temperature characteristic diagram of the food to be thawed,
FIG. 7 is a perspective view of a conventional thawing box, and FIG. 8 is a sectional view of the thawing box. 6... Freezer room 7... Refrigerator room 8... Defrost room 9... Compressor! 0...Cooler + 1-...
Blower + 3-...Damper thermo 24...Second
Temperature detector 27-... Far infrared heater 29...
Reflector plate 30... Ventilation hole 31... Bottom plate 32
... Heater 33 ... First temperature detector 34
-... Thawing dish 35... Food to be thawed 39... Door
40... Ventilation path 63... Thawing control device

Claims (1)

[Claims] A freezing room, a refrigerator room, a thawing room whose outer periphery is surrounded by heat insulating material and has a door that can be opened and closed at the front opening, a refrigeration cycle having a compressor, a cooler, etc., and air cooled by the cooler. a blower for forcing air into each of the freezing compartment, refrigerator compartment, and thawing compartment; a far-infrared heater provided at the top of the thawing compartment; and a heating heater that is thermally conductively in close contact with the back surface of the metal bottom plate; A first temperature sensor is thermally conductively brought into close contact with substantially the center of the back surface of the bottom plate, a metal reflector plate covers the top surface of the far-infrared heater in a dome shape, and food to be thawed is placed thereon. A thawing tray that is thermally conductive and removably installed on the bottom plate, and a damper thermo that is installed at the entrance of the thawing chamber and adjusts the amount of cold air inflow by electrical input, are in communication with each other through this damper thermo, and the A ventilation passage formed in the upper space on the back surface of the reflector, a number of ventilation holes provided in the reflection plate to communicate the ventilation passage with the inside of the thawing chamber, and during thawing, the blower is forced to operate and the thawing time is controlled. The thawing control device divides the thawing time into three stages, and the time from the start of thawing until the temperature of the first temperature sensor rises to a predetermined temperature is defined as the first stage. The infrared heater and the heating heater are continuously energized, and thereafter, in the second and third stages, energization is intermittently performed to both the heaters to reduce the intermittent energization rate, and the first and second
In the step, the damper thermometer is forcibly opened, and in the third step, the damper thermometer is strongly closed, and when the thawing chamber is not thawed, the temperature of the second temperature sensor provided in the thawing chamber is set to the first predetermined temperature. A second temperature sensor that opens and closes the damper thermometer to maintain the temperature in the thawing chamber in a third temperature range between the refrigerating temperature and the freezing temperature, and the temperature of the second temperature sensor is higher than the first predetermined temperature. A refrigerator with a defrosting chamber, characterized in that when the temperature reaches a predetermined temperature, power supply to both of the heaters is stopped.