JPH01181057A - Ice-making device for refrigerating chamber and the like - Google Patents

Abstract

PURPOSE:To prevent ice from being made opaque and to prevent overheating of a heater, by a method wherein a vent hole is formed in a part of a heating plate on the upper surface of an ice-making chamber to which a heating device is disposed, and a temperature sensor and a protecting device to prevent overheating of a heater are situated in a space at the back of the heating plate. CONSTITUTION:The outer wall, except the bottom and the front, of an ice-making chamber 22 is surrounded with a heat insulating material 24. A heater 25 is placed at the back of a top surface, and a heating plate 27 made of aluminum in which a vent hole 26 is formed is situated to one section in the vicinity of a central part. A temperature sensor 28 is positioned at the back of the heating plate 27 and in a space, formed by notching a part of the heat insulating plate 24, in a state to be positioned facing the vent hole 26, and controls energization of the heater 25. An ambient temperature in the ice-making chamber is detected by the temperature sensor 28, the starting of energization of the heating device 25 is more delayed than the starting of ice-making until temperature by the temperature sensor attains a predetermined value, and cooling is performed without heating until the temperature of water is reduced to approximate 0 deg.C. When abnormal heating of the heater 25 occurs, the output of an abnormal temperature increase preventing device 48 is reduced to 'L', the output of an AND circuit 46 is reduced to 'L', a relay contact 34 is opened, the heater 25 is brought into a non-energizing state, and an abnormal heat generating source is disconnected.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an ice-making device that is disposed in a freezer compartment of a refrigerator and is particularly capable of producing transparent ice.

Conventional technology Conventionally, in household refrigerators, etc., an ice making device that stores an ice tray is placed in one section of the freezer compartment, and the water in the ice tray is frozen by the cooling effect of the cold air flowing through the ice making device to make ice. It is common practice to generate .

However, with this ice generation method, when ice is generated, the water in the ice tray progresses from the contact surface between the ice tray and the water and the contact surface between the cold air and water to the center. As a result, gaseous components and impurities dissolved in the water are trapped in the center of the ice, resulting in opaque ice with a cloudy center, which is sensually suitable for beverages such as whisky. It wasn't.

Therefore, the need for transparent ice has existed for a long time, and a method such as the one shown in FIG. 6 is being considered for an apparatus for producing it. The contents will be explained below according to the drawings.

1 is a refrigerator body, and a freezer compartment 3. The lower part is divided into a refrigerator compartment 4. 6 is a cooler for the refrigeration cycle, and 6 is a blower for forced ventilation, respectively.
is located on the back of the.

7 is an ice making device placed at the bottom of the freezer compartment 3;
A first ice-making compartment 8 for producing transparent ice is provided in the upper stage, and a second ice-making compartment 9 for producing regular ice is provided in the lower stage. The first ice making compartment 8 has an outer wall surrounded by a heat insulating material 10 except for the bottom and front, and an aluminum heating plate 12 with a heater 11 on the back is installed on the top, and an aluminum heating plate 12 is installed on the bottom. Aluminum cooling plates 13 are respectively arranged. 14 is a ventilation passage formed below the cooling plate 13, which is 16°16
are the first ice making compartments 8. and 8. respectively. They are a first ice tray and a second ice tray that are housed in the second ice tray 9. Further, 17 is a discharge duct for forcing the cold air cooled by the cooler 6 under the ice making device to be ventilated by the blower 6, and the discharge duct 17 is connected to the ventilation duct 14 and It communicates with the inside of the second ice making chamber 9. 19 is the freezer compartment 3
This is a return duct for returning the cold air discharged into the cooler 6 to the cooler 6. Further, reference numeral 20 denotes a transparent ice making switch, which is configured so that once the switch is turned on, the heater 11 is energized for a predetermined period of time.

In this configuration, the cold air cooled by the cooler 6 is supplied to the freezer compartment 3 and the refrigerator compartment 4 by the forced ventilation action of the blower 6, and at the same time is supplied to the second ice making device 7 through the discharge port 18 of the discharge duct 17. It is discharged into the ice making compartment 9 and the ventilation passage 14. The cold air guided into the second ice making compartment 9 is then
The second ice tray 16 is directly cooled, and the water inside is sequentially frozen on the water surface and the remaining surface that contacts the second ice tray 16 to produce normal ice. However, as mentioned above, the ice produced in this way becomes cloudy and does not become transparent. On the other hand, the cold air guided into the ventilation passage 14 cools the cooling plate 13. Therefore, in order to make transparent ice, the user stores the first ice tray 16 filled with water in the first ice making compartment 8 and turns on the ice making switch 20. 11 starts a heating action via a heating plate 12, and a cooling or freezing action starts from the lower surface via a cooling plate 13. Further, since the outer wall of the first ice tray 16 except the lower surface is covered with the heat insulating material 10, it is not affected by the cooling effect from the freezing chamber 3, and the freezing action progresses in one direction from the lower surface to the upper surface. This freezing effect is indirect cooling via the cooling plate 13, and in addition, a heating effect is added by the heater 11, which has been set to an appropriate capacity in advance, so that the freezing speed is sufficiently slow. Therefore, the speed at which the frozen surface of the ice moves is slower than the upward diffusion speed of the gaseous components in the water, and the dissolved concentration of the gaseous components in the water near the frozen surface becomes thinner, reducing the chance of bubble generation. Furthermore, even if air bubbles are generated, the freezing speed is slow, so the generated air bubbles will not be trapped in the water. If the freezing speed is controlled to approximately ssi+/h or less in this way, the gas components in the water will be degassed from the ice surface to the outside air, so the ice that is finally formed will contain almost no air bubbles. Obtains clear ice. Also, heater 1
No. 1 allows some margin in the time required to complete ice making, and automatically stops energizing after a predetermined time has elapsed.

Problems to be Solved by the Invention However, when the power supply to the heater 11 is started at the same time as the ice-making switch 21 is turned on, that is, when the first ice-making tray 16 filled with water is stored, the first Even during the so-called water state, when the water in the ice tray 16 reaches 0°C and starts freezing, the heating action of the heater 11 is performed from the top surface, so it takes a long time to reach 0°C. C,
As a result, it takes a long time to make ice, or the ice begins to freeze with a very slow cooling effect, so sometimes even when the temperature reaches 0°C, freezing does not begin and the ice remains in the water state. If a so-called supercooling phenomenon occurs, in which the ice is supercooled to below 0°C, and if this condition continues for a long time and there is a delay in returning to the normal freezing state, air bubbles will disperse and form sealed opaque ice, which is an inconvenience. was there. On the other hand, since the front side of the first ice-making compartment 8 opens into the freezing compartment 3, the cooling effect of the cold air in the freezing compartment 3 acts on the front part of the stored first ice-making tray 16. Alternatively, there is also the problem that the freezing conditions for producing transparent ice are unstable, such as being influenced by outside air heat intrusion due to opening and closing of the door of the freezing chamber 3, resulting in poor transparency.

Furthermore, for some reason, no consideration was given to a protection device against abnormal heat generation of the heater 11.

The present invention solves the above-mentioned problems, and aims to provide a safe ice-making device that prevents unnecessary extension of ice-making time and opacity of ice due to overcooling, and also includes measures to prevent heater overheating. The purpose is

Means for Solving the Problems In order to solve the above problems, an ice making device such as a refrigerator according to the present invention has a ventilation hole formed in a part of the heating plate on the top surface of the ice making chamber in which a heating device such as a heater is arranged. A temperature sensor for controlling the heating device and a protection device for preventing overheating of the heater are provided in the space on the back side of the heating plate opposite to the pores.

Function According to the above-described configuration, the temperature sensor detects the atmospheric temperature inside 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 in response to the start of freezing of water. Therefore, cooling is performed without heating until the water reaches approximately 0°C. Furthermore, fires and the like due to overheating of the heater caused by some reason are prevented.

EXAMPLE Hereinafter, an ice making apparatus such as a refrigerator according to an example of the present invention will be described with reference to FIGS. 1 to 6. Note that, conventionally, the same components are given the same reference numerals, and detailed explanation thereof will be omitted.

21 is an ice making device box body 21 provided at the bottom of the freezer compartment 3.
The first one is framed by a and produces transparent ice in the upper layer.
ice making compartment 22, and a second ice making compartment 22 in the lower stage for producing regular ice.
An ice making room 23 is provided.

The first ice-making compartment 22 has an outer wall surrounded by a heat insulating material 24 except for the bottom and front surface, and a heater 26 is provided on the back side of the top surface, and a ventilation hole 26 is provided in a section near the center. An aluminum heating plate 27 is arranged. 28
A temperature sensor is provided on the back side of the heating plate 27 in a space formed by cutting out a part of the heat insulating plate 24, facing the ventilation hole 26, and controls the energization of the heater 26. 29 is a door provided in the front opening of the first ice making compartment 22 so as to be openable and closable; 30 is a transparent ice making switch;
31 is a temperature sensor for controlling the temperature of the freezer compartment 3. Further, 32 is a compressor of a refrigeration cycle provided at the rear of the lower part of the main body 1.

Next, the electric circuit and control circuit will be explained.

The compressor 32 is connected in parallel with the blower 6 and then connected to a power source via a relay contact 33.

Further, the heater 26 is connected in series with the relay contact 34 and then connected to the power source. Next, 35 is a freezing room temperature control device, and temperature sensor 31° resistance R,, R2,
R3, comparison circuit with comparator 36, transistor 37. A relay coil 38 is provided, and the output of the comparator 36 is connected to the base of a transistor 37. Further, a suction relay coil 38 for opening and closing the relay contact 33 is connected to the collector of the transistor 37. 39 is an ice making control device, and a temperature sensor 28. A comparison circuit including resistors R4, R6, R6, a comparator 40, and an ice-making switch 30. Timer 41.42
, an AND circuit 43, a transistor 44, and a relay coil 45, and the output of the comparator 40 is AN
One input of the D circuit 43, the output of the ice making switch 3o is connected to the input of the timer 41, and the output of the timer 41 is connected to the AN
It is connected to the other input of the D circuit 43. Here, once the timer 41 is inputted, it runs for a predetermined time t.

It is configured to output a High signal (hereinafter referred to as "H") after the elapse of time. Next, the output of the AND circuit 43 is connected to the input of the timer 42, and at the same time the output of the AND circuit 43 is connected to the input of the timer 42.
It is also connected to the reset terminal. Here timer 4
2 is constructed so that once input is applied, it continues to output an "H" signal until a predetermined time t has elapsed. The output of the timer 42 is input to one side of an AND circuit 46, and the other side of the AND circuit 46 is connected to the temperature sensor 28.
The output of the abnormal temperature rise prevention device 48, which also serves as the A
The output of the ND circuit 46 is connected to the base of the transistor 44. Further, the collector of the transistor 44 is provided with a suction relay coil 46 that opens and closes the relay contact 34.
is connected.

In this configuration, when the temperature of the freezer compartment 3 is higher than a predetermined value, the resistance value RTH1 of the temperature sensor 31 becomes small and the output of the comparator 36 becomes "H", so the transistor 37 turns ON L, and the relay coil 38 becomes conductive. Then, the relay contact 33 closes and the compressor 32
is operated, and the cooler 6 performs a cooling action. At the same time, the blower 6 is operated, and the cold air cooled by the cooler 5 is forcedly ventilated to the freezer compartment 3, the refrigerator compartment 4, and the discharge duct 17.
It is also supplied to the ice making device 21 via the discharge port 18.

When the cold air that has flowed into the ice making device 21 passes through the ventilation path 14, it is cooled mainly from the water surface of the second ice tray 16 installed in the second ice making compartment 23, and the cold air is cooled down to form normal ice. On the other hand, the cooling plate 13 forming the lower surface of the first ice making chamber 22 is cooled. The cold air that has passed through the ventilation path 14 is returned to the cooler 6 through the return duct 19 together with the cold air that has convected within the freezer compartment 3. Thereafter, when the freezer compartment 3 is cooled to a predetermined temperature, the resistance value RTH1 of the temperature sensor 31 becomes large.
6 generates a low signal (hereinafter referred to as "L"). Therefore, the transistor 37 is turned off and the relay coil 38
The conduction to the compressor 32. is interrupted and the relay contact 33 is opened. The blower 6 stops. Thereafter, this action is repeated to perform the normal cooling action, and the cooling plate 13 of the first ice making compartment 22 is also maintained sufficiently cooled. In this state, when the user tries to make transparent ice and puts the first ice tray 15 filled with water into the first ice making compartment 22 and turns on the ice making switch 30 at the same time, the @H'' signal is output and the timer is turned on. 41.The subsequent operation will be explained using the characteristic diagram in FIG.
One input of the ND circuit 43 becomes "H". At this point, the water filled in the first ice tray 16 is being cooled down to 0°C by the cooling action of the cooling plate 13.
By inserting the ice cube tray 16, the water temperature (in this case, (T)℃)
The atmospheric temperature inside the first ice-making compartment 22 rises due to the influence of
The temperature at No. 8 also shows a rapid temperature rise curve. However, this rising curve reaches its peak within a short period of time, and thereafter changes to a temperature decreasing curve as the water temperature falls. timer 4
The delay time t0 of 1 is set so as to occur after the temperature characteristic of the temperature sensor 28 turns to a downward curve, and thereafter, as the water temperature falls, the temperature sensor 28 is also cooled and the resistance value RTH2 increases. When the temperature of the temperature sensor 28 reaches a predetermined temperature T°C corresponding to the water temperature reaching O'C, the output of the comparator 4o becomes @H.
”, and the other input of the AND circuit 43 also becomes “H”. At this point, the output of the AND circuit 43 becomes “H” for the first time.
becomes. On the other hand, the "H" output of the AND circuit 43 is input to the reset terminal of the timer 41 to reset the contents of the timer 41 in preparation for the next turning on of the ice making switch 30.

On the other hand, the signal is input to the timer 42 and continues to output an "H" signal for a predetermined time t.If the temperature of the heater 11 is normal, the output of the abnormal temperature rise prevention device 48 becomes "H", and the AND circuit 46 The output of the transistor 44 becomes "H".Then, the transistor 44 conducts the 0NLIJ relay coil 46 for the predetermined time t, the relay contact 34 closes, and the heater 2
6 is energized. In other words, the heating action from the heating plate 27 on the top surface of the first ice-making compartment 22 is not started until the water temperature reaches approximately O"C, and the state of the water until it reaches O"C. The wasteful heating action in the process can be omitted, and the ice making time is shortened accordingly. Further, since the temperature sensor 28 indirectly detects the water temperature and controls the heating start time, it is versatile even when the water temperature changes. Furthermore, since it is possible to avoid slow cooling while heating, the freezing action from water to ice occurs normally at the freezing point of 0°C, resulting in a supercooling phenomenon in which water is supercooled to below 0"C. The risk of forming opaque ice is eliminated.

Then, the heating effect from the heating plate 27 on the upper surface prevents the water surface from freezing first, and the cooling effect from the cooling plate 13 on the lower surface causes the water to freeze in one direction from below to upward, so that when time t has elapsed, The gaseous components contained in the water are degassed from the ice surface, producing transparent ice containing almost no air bubbles. Incidentally, the time t is determined by giving a certain margin to the time required for the water to finish freezing. Then, when the time t has elapsed, the output of the timer 42 becomes "L".
The transistor 44 is 0FFL, the relay coil 45 is cut off, the relay contact 34 is opened, and the flow to the heater 26 is stopped. When the power supply to the heater 26 is stopped, the heating effect from the heating plate 27 disappears, and the cooling effect from the cooling plate 13 on the lower surface rapidly cools the heater 26. On the other hand, the heater 2
6, if abnormal heat generation occurs for some reason, the output of the abnormal humidity rise prevention device 48 becomes Low (hereinafter referred to as "L"), the output of the AND circuit 4e becomes "L", and the relay is activated. The contact 34 is opened and the heater 26 is de-energized, cutting off the source of abnormal heat generation and preventing unsafe accidents such as fire.

Effect 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, the point at which it starts freezing, is shortened, and the time required to make transparent ice can be shortened. or,
It is versatile and can always be effective even under different water temperature conditions.

(2) Since it is possible to eliminate the slow cooling state by heating in the cooling section from water to ice, it is possible to prevent the occurrence of supercooling phenomenon and to prevent the mixing of opaque ice.

(3) Measures are taken to prevent abnormal temperature rises in heating equipment, and there have been no accidents such as fires.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of an ice making apparatus such as a refrigerator showing an embodiment of the present invention, Fig. 2 is a front view of the ice making apparatus shown in Fig. Figure 4 is an electric circuit and control circuit diagram of the refrigerator shown in Figure 3, and Figure 6 is a characteristic diagram when producing transparent ice with the ice making device shown in Figures 1 and 2. , FIG. 6 is a sectional view of a refrigerator equipped with a conventional ice making device. 13...Cooling plate, 16.River...First ice tray (
ice making tray), 21... ice making device, 22... first ice making compartment (ice making compartment), 24... exit/insulation material, 25...
... Heater (heating device), 26 ... Ventilation hole, 27 ... Heat plate, 28 ... Temperature sensor, 48 ... Abnormal temperature rise Prevention device. Name of agent: Patent attorney Toshio Nakao and one other person I3
・-Cooling plate 15- 1st water production (Ice production 2) 21-Ice production 1 ??- @ 7 water production! (Ice production 24- Insulation material 25- Heater (open yL) 26- Direct J Hole 27-=, ff+) 1st ice tray, (Ice making X) 21°-Water making table 1 22- 1)% water fish (ice making!)

Claims (1)

[Claims] a cooling plate; an ice-making compartment partitioned with the cooling plate as the bottom and an open front; an ice-making tray stored in the ice-making compartment and placed on the cooling plate; and a heating device provided on the top surface of the ice-making tray. a heating plate provided with a heating plate, a ventilation hole formed in a part of the heating plate, a temperature sensor for controlling the heating device provided in a space on the back side of the heating plate opposite to the ventilation hole, and the ice making device. An ice making device such as a refrigerator comprising a heat insulating material disposed within the outer wall of the chamber excluding the bottom and front surface, and an abnormal temperature rise prevention device of the heating device configured using the temperature sensor.