JPH0674937B2 - 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 the ice has been described in, for example, Shokai 58-6977.
A method as shown in Japanese Patent No. 9 is considered. The basic structure 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 ventilation 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 ventilation passage 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 manufacturing dish 15 except for 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 ice frozen surface is slower than the upward diffusion speed of the gaseous component in the water, the dissolved concentration of the gaseous component in the water near the frozen surface is thinned, and the chance of generating bubbles is reduced. Further, even if bubbles are generated, the freezing speed is slow, so the generated bubbles are not captured in ice. If the freezing speed is controlled to about 3 mm / h or less in this way, the gas components in the water are degassed from the surface of the water that freezes last to the outside air, so that the ice finally produced contains almost no air bubbles. Clear 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 problems described above, and provides an ice making device capable of stably producing transparent ice by preventing wasteful extension of ice making time and opacity of ice due to a supercooling phenomenon. Has an aim.

Means for Solving the Problems In order to solve the above problems, the ice-making device such as the refrigerator of the present invention forms a vent hole in a part of the heating plate on the upper surface of the ice-making chamber in which the heating means such as a heater is arranged. A temperature sensor is provided in the back space of the heating plate facing the ventilation hole, the cooling means is continuously operated from the start of ice making, and if the temperature sensor is below the predetermined temperature after the lapse of the first predetermined time, Two
After the lapse of a predetermined time, the continuous operation of the cooling means is released and the heating means is operated, and when the temperature is equal to or higher than the predetermined temperature, the continuous operation of the cooling means is reached after the third predetermined time has elapsed after reaching the predetermined temperature. Is released and the heating means is operated.

Operation According to the present invention, the temperature sensor indirectly detects the water temperature when the ice tray is put in, and when the temperature after the first predetermined time is lower than the predetermined temperature, it is determined that the water temperature is low. When the second predetermined time arrives, the continuous operation of the cooling means is released and the heating means operates. On the other hand, when the temperature is higher than the predetermined temperature, it is judged that the water temperature is high, and the continuous operation of the cooling means is extended until the third predetermined time is reached after reaching the predetermined temperature, and then the heating means operates. Therefore, the appropriate continuous cooling period and the operation timing of the heating means are selected according to the water temperature.

Example An ice making apparatus such as a refrigerator according to an example of the present invention will be described below with reference to FIGS. 1 to 4. 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.
Reference numeral 29 is a door body provided at the front opening of the first ice making chamber 22 so as to be openable and closable, 30 is a transparent ice making switch, and 31 is a temperature sensor for controlling the temperature of the freezing chamber 3. or,
Reference numeral 32 denotes a refrigeration 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, a temperature sensor 31, resistors R ₁ , R ₂ , R ₃ , a comparison circuit including a comparator 36, OR
A circuit 37, a transistor 38, and a relay coil 39 are provided. The output of the comparator 36 is connected to one input of the OR circuit 37, and the output of the OR circuit 37 is connected to the base of the transistor 38. The collector of the transistor 38 is connected to a relay coil 39 for attraction that opens and closes the relay contact 33.

40 is an ice making control device, which includes a temperature sensor 28, resistors R ₄ , R ₅ ,
R _6, comparator circuit, the ice making switch 3 having a comparator 41
0, timer 42, 43, 44, 45, OR circuit 46, 47, inverter 4
8, a transistor 49 and a relay coil 50. The output of the comparator 41 is connected to the input of the timer 44, and the output of the timer 44 is connected to one input of the OR circuit 46. The output of the ice making switch 30 is connected to the input of the timer 42, the output of the timer 42 is connected to the other input of the OR circuit 46, and the inverter
It is also connected to the 48 inputs. The output of the inverter 48 is connected to the input of the timer 43, and the output of the timer 43 and the output of the OR circuit 46 are both connected to the input of the OR circuit 47. The output of the OR circuit 47 is connected to the other input of the OR circuit 37 of the freezer compartment temperature control device 35 and also to the input of the timer 45. The output of the timer 45 is connected to the base of the transistor 49 and the collector of the transistor 49 is connected to the relay contact.
A relay coil 50 for opening and closing 34 is connected.

Here, the timer 42 outputs a high signal (hereinafter, simply “H”).
"H" for the _first predetermined time (t ₁ )
Emit a signal. When the "H" signal is input, the timer 43 issues the "H" signal only for the second predetermined time (t ₂ ). When the input signal is "H", the timer 44 outputs the "H" signal, and when the input signal changes from "H" to Low signal (hereinafter, simply referred to as "L") Predetermined time (t ₃ )
Emits "H" signal only. The timers 45 are each configured to issue an "H" signal for a predetermined time (t ₄ ) after the input signal changes from "H" to "L".

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”. It becomes “H”, the transistor 3 turns on, and the relay coil 3 becomes conductive. 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 is also supplied to the ice making device 21 via the discharge duct 17 and the discharge port 18. When the cold air flowing into the ice making device 21 passes through the ventilation passage 4,
On the other 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, and on the other hand, the lower surface of the first ice making chamber 22 is formed. The cooling action of the cooling plate 13 is performed. Then, the cool air that has passed through the ventilation passage 14 returns together with the cool air that has convected inside the freezing chamber 3 and returns to the duct.
It is returned to the cooler 5 through 19. After that, if the freezer compartment 3 is cooled to a predetermined temperature, the resistance value R _{TH1 of the} temperature sensor 31.
Becomes larger and the comparator 36 generates a low signal (hereinafter referred to as “L”). For this reason, the transistor 38 is turned off, the conduction to the relay coil 39 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 first ice making chamber 22
The cooling plate 13 is also 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. 42
Entered in. The subsequent operation is shown in the characteristic diagram of FIG.
The case where the initial water temperature is low (for example, 10 ° C.) and the case where the initial water temperature is high (for example, 30 ° C.) will be described separately.

First, when the initial water temperature is low, when the "H" signal is input to the timer 42, the first ice tray is made through the ventilation hole 26 of the heating plate 27.
The temperature of the temperature sensor 28 suddenly rises under the influence of the heat in the water inside 15. And the first predetermined time (t ₁ , eg 10 m
in), the output of the timer 42 changes from "H" to "L", while the output of the timer 42 is "H", that is, one input of the OR circuit 46, one input of the OR circuit 47, and the OR circuit 37. Since one of the inputs becomes "H", the transistor 38 is turned on, the relay coil 39 is turned on, the relay contact 33 is turned on, and the compressor 32 and the blower 6 are forcibly operated continuously. Therefore, the water in the first ice tray 15 is rapidly cooled to 0 ° C. But,
When the initial water temperature is low, the peak of the rising curve of the temperature sensor 28 does not reach the predetermined temperature (T ₁ such as −3 ° C.) set in advance, so the output of the comparator 41 remains “L” from beginning to end, The output of the timer 44 is also "L", that is, one input of the OR circuit 46 is "L". Therefore, when the output of the timer 42 after a first predetermined time period (t ₁₎ is changed as "H" → "L", the input of the OR circuit 46 becomes "L" in both the antagonist. On the other hand, the changed output “L” of the timer 42 is converted into “H” by the inverter 48 and input to the timer 43. And timer 43
Continues to generate the output "H" for the second predetermined time (t ₂ , for example, 15 min). Therefore, the inputs of the OR circuit 47 and the OR circuit 37 also become “H” during this period, and the compressor 32 and the blower 6 continue.
Is forced to operate continuously. Then, when the second predetermined time (t ₂ ) is reached, the output of the timer 43 changes from “H” to “L”, so the input of the OR circuit 47, that is, the timer 45 also changes to “H” →
Change to "L". Therefore, the timer 45 generates an output “H” thereafter for a predetermined time (t ₄ , for example, 10), the transistor 49 is turned on, the relay coil 50 is turned on, the relay contact 34 is turned on, and the heater 25 is turned on. Is energized. Here, only the time obtained by adding the first predetermined time (t ₁ ) and the second predetermined time (t ₂ ),
When the compressor 32 and the blower 6 are continuously operated, if the time is set in advance so as to be cooled to around 0 ° C. when the initial water temperature is low, the compressor will be operated after the _second predetermined time (t ₂ ) has elapsed.
The continuous operation of the fan 32 and the blower 6 is released, and the heating action of the heater 25 is efficiently taken over.

Next, since the temperature rise curve of the temperature sensor 28 is steep especially when the initial water temperature is high, the temperature sensor 28 is already at the time when the timer 42 counts the _first predetermined time (t ₁ ).
Temperature of 28 output of the comparator 41 to have risen than the predetermined temperature (T ₁ for example -3 ° C.) is made to "H".
Therefore, the output of the timer 44 is "H", and based on this, the "H" signal is sent to the transistor 38 via the OR circuits 46, 47, 37, and the compressor 32 and the blower 6 continuously operate. Then, the temperature of the temperature sensor 28 goes beyond the peak and shifts to the temperature drop curve in accordance with the drop of the water temperature, and reaches a predetermined temperature (T ₁ e.g.
3 ℃), the output of comparator 41 goes from "H" to "L"
Changes to. However, the input signal of the timer 44 is "H" →
Third predetermined time (t ₃ , eg 25 min) even after changing to “L”
Therefore, the "H" signal is continuously output with a delay, so that the "H" signal is continuously sent to the transistor 38 through the OR circuits 46, 47 and 37 during that time, and the compressor 32 and the blower 6 continue to operate continuously. Thereafter, when the output of the third predetermined time period (t ₃₎ has elapsed the timer 44 becomes "L", the input of the timer 45 for output of the OR circuit 46 and 47 becomes "L" also "H" → Change to "L". Therefore, the timer 45 thereafter generates the output “H” for a predetermined time (t ₄ , for example, 10h) and the transistor 49 is turned on.
Then, the heater 25 is energized. Here, the time required to reach the water temperature of 0 ° C. from the time when the predetermined temperature (T ₁ for example −3 ° C.) is reached converges to a level where there is no great difference even if the initial water temperature is slightly different. If the predetermined time (t ₃ ) is properly determined, even if the initial water temperature is high, the continuous operation of the compressor 32 and the blower 6 can be efficiently canceled when the water temperature almost reaches 0 ° C. , The heating action by the heater 25 is started.

That is, whether the initial water temperature is low or high, not only the unnecessary heating action in the water state until reaching 0 ° C. can be omitted, but also the cooling plate 13 is forcedly and continuously in the meantime.
It is possible to shorten the time (t) required for ice making in order to perform the cooling action via the. 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 while heating is avoided, the freezing action from water to ice is normally performed at the freezing point of 0 ° C, and the water is supercooled to below 0 ° C. Eliminates the risk of producing fresh ice.

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 can be shortened, and the time for making transparent ice can be shortened.
Further, even if the water temperature condition is different, it is versatile and can always exert its effect.

(2) Since the gradual cooling state due to 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 an electric circuit and control circuit diagram of the ice making device, and FIG. 3 is an ice making characteristic diagram of the ice making device. FIG. 5 is a sectional view of a refrigerator equipped with the ice making device, and FIG. 5 is a sectional view of a refrigerator equipped with an ice making device showing a conventional example. 13 ... Cooling plate (cooling means), 15 ... First ice tray (ice tray) 21 ... Ice making device, 22 ... First ice making chamber (ice making chamber) 24
...... Insulation material, 25 …… Heater (heating means), 26 …… Vent hole, 27 …… Heating plate, 28 …… Temperature sensor, 40 …… Ice-making control device.

Claims (1)

[Claims] 1. An ice making chamber having a cooling means such as a cooling plate, the cooling means on the bottom surface, the front surface being opened and defined, and the heat insulation provided in an outer wall excluding the bottom surface and the front surface of the ice making room. Material, an ice tray stored in the ice making chamber and placed on the cooling plate, a heating plate having a heating means such as a heater provided on the upper surface of the ice tray, and a part of the heating plate A ventilation hole, a temperature sensor provided in a back space of the heating plate facing the ventilation hole, an ice making switch for operating the heating device to perform an ice making operation, and the cooling at the same time when the ice making switch is turned on. When the means is continuously operated and the temperature of the temperature sensor is equal to or lower than a predetermined temperature after a first predetermined time has elapsed since the ice making switch was turned on,
After the elapse of the second predetermined time, the continuous operation of the cooling means is released to operate the heating means, and when the temperature of the temperature sensor is equal to or higher than the predetermined temperature, the third temperature is reached after reaching the predetermined temperature.
The ice-making device such as a refrigerator, which is provided with an ice-making control device that releases the continuous action of the cooling means and causes the heating means to act after a predetermined time.