JPH0672730B2 - Ice makers such as refrigerators - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ice making device arranged in a freezer or the like of a refrigerator and capable of producing particularly transparent ice.

2. Description of the Related Art Conventionally, in household refrigerators and the like, an ice making device for accommodating an ice making plate is arranged in one part of a freezing room, and the water in the ice making plate is frozen by the cooling action of the cold air flowing through the ice making device. Is generally generated.

However, with such an ice production method, freezing of water in the ice tray during ice production proceeds from the contact surface between the ice tray and water and the contact surface between cold air and water to the central portion. Therefore, gas components and impurities dissolved in water are confined in the center of the ice, resulting in opaque ice with a cloudiness in the center, which is organoleptically suitable for beverages such as whiskey. Was not.

Therefore, there is a need for transparent ice from the past, and a device for producing it has been described in, for example, Shoukai Sho 58-69779.
A method as shown in Japanese Patent Publication is considered. The basic configuration and operation will be described below with reference to FIG.

Reference numeral 1 denotes a refrigerator main body, which is divided by a partition wall 2 into a freezer compartment 3 at the top and a refrigerating compartment 4 at the bottom. Reference numeral 5 is a cooler for the refrigeration cycle, and 6 is a blower for forced ventilation, which are arranged on the back surface of the freezing chamber 3, respectively. Reference numeral 7 denotes an ice making device arranged at the bottom of the freezing compartment 3, and a first ice making compartment 8 for producing transparent ice in an upper stage and a second ice making compartment for producing ordinary ice in a lower stage. 9 is provided. The outer wall of the first ice making chamber 8 excluding the bottom surface and the front surface is surrounded by a heat insulating material 10.
Aluminum heating plate 12 with heater 11 on the back
However, aluminum cooling plates 13 are arranged on the bottom surface, respectively. 14 is an air passage formed below the cooling plate 13,
Reference numerals 15 and 16 denote a first ice tray and a second ice tray which are housed in the first ice making chamber 8 and the second ice making chamber 9, respectively. Reference numeral 17 denotes a discharge duct for forcing the cool air cooled by the cooler 5 to the ice making device 7 by the blower 6, and a discharge port 18 formed at the lower end of the discharge duct 17 and the second passage 14 respectively. It communicates with the inside of the ice making chamber 9. Reference numeral 19 is a return duct for returning the cool air discharged into the freezer compartment 3 to the cooler 5. Further, reference numeral 20 is a transparent ice making switch, which is configured to energize the heater 11 for a predetermined time when the switch is turned on once.

In such a configuration, the cool air cooled by the cooler 5 is supplied to the freezing chamber 3 and the refrigerating chamber 4 by the forced ventilation of the blower 6, and at the same time, the second air in the ice making device 7 is discharged through the discharge port 18 of the discharge duct 17. It is discharged to the ice making chamber 9 and the ventilation passage 14.
Then, the cold air introduced into the second ice making chamber 9 directly cools the second ice making tray 16, and the water in the inside is sequentially frozen from the water surface and the remaining surface in contact with the second ice making tray 16. Generates normal ice. However, as described above, the ice generated in this way is cloudy and does not become transparent ice. On the other hand, the cold air introduced into the fan 14 cools the cooling plate 13. The first ice tray filled with water so that the user can make clear ice.
When 15 is housed in the first ice making chamber 8 and the ice making switch 20 is turned on, a heating plate by the heater 11 is applied from the upper surface of the first ice making tray 15.
The heating action is started via 12 and the cooling plate 13
The cooling or freezing action via the is initiated. Further, since the outer wall of the first ice tray 15 excluding the lower surface is covered with the heat insulating material 10, it is not affected by the cooling from the freezer compartment 3, and the unidirectional freezing action progresses from the lower surface to the upper surface. This freezing action is not only indirect cooling through the cooling plate 13 but also the heating action by the heater 11 which is set to an appropriate capacity in advance, so that the freezing rate becomes sufficiently slow. Therefore, the traveling speed of the frozen surface of the ice is slower than the upward diffusion speed of the gas component in the water, the dissolved concentration of the gas component in the water in the vicinity of the frozen surface becomes thin, and the chance of generating bubbles is reduced. Further, even if bubbles are generated, the freezing speed is slow and the bubbles are not caught in the ice. In this way, the freezing speed is about 3 mm / h
If the water content is controlled to the following level, the gas component in the water is degassed from the surface of the water that freezes last to the outside air, so that the finally produced ice contains almost no bubbles and transparent ice is obtained. In addition, the heater 11 has a certain margin in the time required to complete the ice making, and the power supply is automatically stopped when a predetermined time elapses.

However, at the same time when the ice making switch 21 is turned on,
That is, when energization of the heater 11 is started from the time when the first ice tray 15 filled with water is stored, until the water in the first ice tray 15 reaches 0 ° C. and starts freezing. Since the heating action of the heater 11 is performed from the upper surface even during the so-called water state, it takes a long time to reach 0 ° C., and as a result, it takes a long time to complete the ice making or a very gentle cooling action. In some cases, so-called supercooling phenomenon occurs in which freezing does not start even when the temperature reaches 0 ° C, and the water is still supercooled below 0 ° C. If there is a delay in returning to a normal freezing state due to fluttering, there is a problem that air bubbles are dispersed and opaque ice is contained.

The present invention solves the above-mentioned problems, and an object of the present invention is to provide an ice making device capable of preventing waste or extension of ice making time and opacity of ice due to a supercooling phenomenon.

Means for Solving the Problems In order to solve the above problems, an ice making device such as a refrigerator of the present invention has a vent formed in a part of a heating plate on an upper surface of an ice making chamber in which a heating device such as a heater is arranged. A temperature sensor for controlling the heating device is provided in the space on the back side of the heating plate facing the ventilation hole.

Action According to the present invention, the temperature sensor detects the ambient temperature in the ice making chamber, which is affected by the water temperature in the ice making tray, through the ventilation hole provided in the heating plate. Then, for example, the start of energization of the heating device is delayed from the start of ice making until the temperature sensor reaches a predetermined temperature corresponding to the start of freezing of water. Therefore, cooling is performed without heating until the water reaches approximately 0 ° C.

Example An ice making device such as a refrigerator according to an example of the present invention will be described below with reference to FIGS. 1 to 5. Incidentally, conventionally, the same components are designated by the same reference numerals, and detailed description thereof will be omitted.

Reference numeral 21 denotes an ice making device provided in the lower portion of the freezing compartment 3, which is framed by a box 21a, and has a first ice making compartment 22 for producing transparent ice in the upper stage and a first ice making chamber for producing normal ice in the lower stage. Two ice making chambers 23 are provided. The outer wall of the first ice making chamber 22 excluding the bottom surface and the front surface is surrounded by a heat insulating material 24. A heater 25 is provided on the top surface on the back surface, and a vent hole 26 is provided in one stroke near the center. A formed heating plate 27 made of aluminum is arranged. Reference numeral 28 denotes a temperature sensor provided on the back side of the heating plate 27 so as to face the ventilation hole 26 in a space formed by cutting out a part of the heat insulating plate 24, and controls the energization of the heater 25.
29 is the temperature sensor 28 formed by a part of the box 21a
Is a locking claw for locking the. Reference numeral 30 is a transparent ice making switch, and 31 is a temperature sensor for controlling the temperature of the freezer compartment 3. Reference numeral 32 is a refrigerating cycle compressor provided in the lower rear part of the main body 1.

Next, the electric circuit and the control circuit will be described. The compressor 32 is connected in parallel with the blower 6 and then connected to a power source via a relay contact 33. The heater 25 is connected to the power source after being connected in series with the relay contact 34. Next, 35 is a freezer compartment temperature control device, which is equipped with a temperature sensor 31, resistors R ₁ , R ₂ , R ₃ , a comparison circuit including a comparator 36, a transistor 37, and a relay coil 38. The output is connected to the base of transistor 37. The collector of the transistor 37 is connected to a suction relay coil 38 for opening and closing the relay contact 33. 39 is an ice making control device, and a temperature sensor 2
8, a resistor R ₄ , R ₅ , R ₆ , a comparison circuit including a comparator 40, an ice making switch 30, timers 41 and 42, an AND circuit 43, a transistor 44, and a relay coil 45, and the comparator 4
The output of 0 is to one input of the AND circuit 43, the output of the ice making switch 30 is to the input of the timer 41, and the output of the timer 41 is the above-mentioned AN.
It is connected to the other input of D circuit 43. Here, the timer 41 becomes Hi after a predetermined time t _{0 has} passed once the input is turned on.
It is configured to output a gh signal (hereinafter referred to as "H"). Next, the output of the AND circuit 43 is connected to the input of the timer 42 and at the same time connected to the reset terminal of the timer 41. Here, the timer 42 is configured to continue to output the "H" signal until a predetermined time t elapses when the input is made once. The output of timer 42 is then connected to the base of transistor 44. Also, a transistor
A relay coil 45 for suction that opens and closes the relay contact 34 is connected to the collector of 44.

In such a configuration, when the temperature of the freezer compartment 3 is higher than the predetermined value, the resistance value R _TH1 of the temperature sensor 31 becomes small and the output of the comparator 36 becomes “H”, so that the transistor 37 is turned on and the relay coil is turned on. 38 conducts. Then, the relay contact 33 is closed, the compressor 32 is operated, and the cooler 5 performs a cooling action. At the same time, the blower 6 is operated, and the cool air cooled by the cooler 5 is forcedly ventilated to the freezing compartment 3 and the refrigerating compartment 4, and the ice making device 21 is also discharged through the discharge duct 17 and the discharge port 18.
Will also be supplied. The cold air that has flowed into the ice making device 21 is a ventilation passage.
When passing through 14, on the one hand, the second ice tray 16 installed in the second ice making chamber 23 is cooled mainly from the water surface to perform normal ice producing action, while on the other hand, Ice making room
The cooling action of the cooling plate 13 forming the lower surface of 22 is performed. The cool air that has passed through the ventilation passage 14 is returned to the cooler 5 through the return duct 19 together with the cool air that has convected inside the freezer compartment 3. After that, if the freezer compartment 3 is cooled to a predetermined temperature, the resistance value R _TH1 of the temperature sensor 31 becomes large and the comparator 36 becomes Low.
Signal (hereinafter referred to as "L") is generated. For this reason, the transistor 37 is turned off, the conduction to the relay coil 38 is cut off, the relay contact 33 is opened, and the compressor 32 and the blower 6 are stopped. Thereafter, this operation is repeated to perform a normal cooling operation, and the cooling plate 13 of the first ice making chamber 22 is sufficiently cooled and maintained. In this state, when the user stores the first ice tray 15 filled with water in the first ice making chamber 22 in an attempt to make transparent ice, when the ice making switch 30 is turned on at the same time, the "H" signal is output and the timer is activated. Entered in 41. The subsequent operation is the fifth
To explain using the characteristic diagram of the figure, when the “H” signal is input to the timer 41, the “H” signal is output after a delay of a predetermined time t ₀ , and one input of the AND circuit 43 becomes “H”. Become. This time is a process in which the water filled in the first ice tray 15 is cooled toward 0 ° C. by the cooling action of the cooling plate 13, and the water temperature (in this case, 30 ° C. due to the insertion of the first ice tray 15). ), The ambient temperature in the first ice making chamber 22 rises, and the temperature of the temperature sensor 28 also draws a sharp temperature rise curve through the ventilation holes of the heating plate 27 provided on the upper surface. However, this rising curve reaches a peak in a short time, and thereafter, it changes to a temperature falling curve as the water temperature drops. The delay time t ₀ of the timer 41 is set so that the temperature characteristic of the temperature sensor 28 is changed to the falling curve, and thereafter, the temperature sensor 28 is also cooled and the resistance value R _TH2 increases as the water temperature decreases. . Then, when the temperature of the temperature sensor 28 reaches a predetermined temperature T ° C. corresponding to the water temperature reaching 0 ° C., the output of the comparator 40 becomes “H” and the other input of the AND circuit 43 also becomes “H”. The output of the AND circuit 43 becomes "H" for the first time at this time. The "H" output of the AND circuit 43 is the timer 41
Is input to the reset terminal to reset the contents of the timer 41 to prepare for the next turning of the ice making switch 30. On the other hand, the "H" signal is continuously output for the predetermined time t input to the timer 42. The transistor 44 is turned on during that time, the relay coil 45 is turned on, the relay contact 34 is closed, and the heater is turned on.
25 is energized. That is, the heating action from the heating plate 27 on the upper surface of the first ice making chamber 22 is started after the water temperature reaches almost 0 ° C., and there is no waste of water until reaching 0 ° C. The heating action can be omitted and the ice-making time becomes shorter accordingly. Further, since the temperature sensor 28 indirectly detects the water temperature and controls the heating start time, it has versatility even if the water temperature changes. Furthermore, since the gradual cooling state can be avoided while heating, the freezing action from water to ice is normally performed at the freezing point of 0 ° C.
There is no risk of opaque ice due to a supercooling phenomenon in which water is supercooled to below 0 ° C. Then, since the water surface is not frozen first by the heating action from the upper heating plate 27 and the water is frozen in one direction from the lower side to the upper side by the cooling action from the lower cooling plate 13, when the time t elapses. The gas component contained in the water is degassed from the surface of the water, and transparent ice containing almost no bubbles is generated. The time t is required for the water to finish freezing.

The time length is set so that the required time has a certain allowance. Then, when the time t has passed, the output of the timer 42 is "L".
Then, the transistor 44 is turned off, the conduction of the relay coil 45 is cut off, the relay contact 34 is opened, and the power supply to the heater 25 is stopped. When the power supply to the heater 25 is stopped, the heating plate 27
There is no heating action from the cooling plate 13 and the cooling action from the cooling plate 13 on the lower surface results in rapid cooling.

Effects of the Invention As described above, according to the present invention, the following effects can be obtained.

(1) The time required for water to reach 0 ° C. at which freezing starts is shortened, and the time required for making transparent ice can be shortened. or,
Even if the water temperature condition is different, it is versatile and can always exert its effect.

(2) Since the gradual cooling state by heating in the cooling section from water to ice can be eliminated, the occurrence of a supercooling phenomenon can be prevented and opaque ice can be prevented from mixing.

[Brief description of drawings]

FIG. 1 is a sectional view of an ice making device such as a refrigerator showing an embodiment of the present invention, FIG. 2 is a front view of FIG. 1, and FIG.
Fig. 2 is a sectional view of a refrigerator equipped with the ice making device, Fig. 4 is an electric circuit and a control circuit diagram of the refrigerator shown in Fig. 3, and Fig. 5 is the ice making device shown in Fig. 1 and Fig. 2. FIG. 6 is a cross-sectional view of a refrigerator equipped with a conventional ice making device, which is a characteristic diagram for producing transparent ice. 13 …… Cooling plate, 15 …… First ice tray (ice tray), 21 ……
Ice maker, 22 …… First ice maker (ice maker), 24 …… Insulation material, 25 …… Heater (heater), 26 …… Vent hole, 27 ……
Heating plate, 28 ... Temperature sensor.

Claims (1)

[Claims] 1. A cooling plate, an ice making chamber having the cooling plate as a bottom face and opening at the front face to form a compartment, an ice making plate housed in the ice making chamber and placed on the cooling plate, and an upper face of the ice making plate. A heating plate provided with a heating device such as a heater provided in the heating plate; a vent hole formed in a part of the heating plate; and the heating device provided in the back space of the heating plate facing the ventilation hole. An ice making device such as a refrigerator comprising a temperature sensor for controlling the temperature and a heat insulating material arranged in an outer wall of the ice making chamber excluding the bottom surface and the front surface.