JPH0933156A - Refrigerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To finish a defrosting operation at an adequate timing and to reduce the number of temperature sensors by finishing the defrosting operation at detected temperature that is equal to or higher than second temperature that is higher than first temperature by an air temperature sensor, when the detected room temperature is lower than the predetermined temperature. SOLUTION: When the detected temperature by the room temperature sensor 23 is equal to or higher than 12 deg.C that is the predetermined temperature, a compressor 22 keeps on being supplied with power but defrosting operation finished by cutting off the power to a defrosting heater 17. When the detected temperature by the room temperature sensor 23 is lower than 12 deg.C, the detected temperature of the air temperature sensor 19 is judged if it reaches 15 deg.C that is the second temperature and when it reaches 15 deg.C, the compressor 22 is kept on being supplied with the power but the power to the defrosting heater 17 is cut off and the defrosting operation is ended. Therefore, the defrosting operation is ended at the adequate timing and the timing of finishing the defrosting operation is detected by single sensor arranged to the chilling unit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerator for heating a cooler with a heater for defrosting.

[0002]

In a refrigerator of this type, for example, a fan-cool type refrigerator, air cooled by a cooler (cool air) is circulated in the refrigerator by a fan to cool the refrigerator. . In this case, the water contained in the air flowing through the cooler portion becomes frost and adheres to the cooler. Therefore, as is well known, the defrosting operation is executed by heating the cooler with the defrosting heater. This defrosting operation is performed, for example, when the defrosting heater is energized when the accumulated operating time of the compressor reaches a predetermined time, and when the temperature of the cooler detected by the temperature sensor provided in the cooler reaches a predetermined temperature. It was determined that the defrosting was completed, and the defrosting heater was controlled to be turned off.

However, even when the defrosting operation is executed at a predetermined timing, there is a situation in which the amount of frost formed on the cooler fluctuates due to the amount of moisture in the air, and the temperature varies depending on the amount of frost formation. Sometimes the followability of the sensor changed and the defrosting operation could not be terminated at an appropriate time. Such a tendency is
This is particularly noticeable in large refrigerators (large coolers).

Therefore, in recent years, as shown in FIG. 11, the temperature sensors 2 and 3 are partially provided at two upper portions of the cooler 1. Of these temperature sensors 2 and 3, the temperature sensor 2 on the right side of the drawing is configured to detect the air temperature (air temperature) around the cooler 1 (hereinafter, referred to as “air temperature sensor 2”), and is relatively worn. The amount of frost is large, and it is provided in the part where frost tends to remain until the end when defrosting. On the other hand, the temperature sensor 3 on the left side of the drawing is configured to directly detect the temperature (evaporation temperature) of the cooler 1 (hereinafter referred to as "evaporation temperature sensor 3"). The defrost heater 4 is provided below the cooler 1.

In such a configuration, the control of the defrosting operation is
This is performed as shown in the flowchart of FIG. 12, and the defrosting operation is ended when the evaporation temperature sensor 3 detects a temperature of 13 ° C. or higher and the air temperature sensor 2 detects a temperature of 13 ° C. or higher, for example. It is like this.

The reason why the two defrosting operations are terminated by using the two temperature sensors 2 and 3 as described above is as follows. That is, FIG. 13 shows the temperature detected by the air temperature sensor 2 (shown by a dotted line in the figure) and the evaporation temperature sensor 3 when the frost attached to the cooler 1 is completely melted with respect to the amount of frost formed on the cooler 1. The relationship between the detected temperatures (shown by the solid line in the figure) is shown. As can be seen from the figure, when the amount of frost is large, the evaporation temperature rises earlier than the air temperature detected at a position in the cooler 1 where the amount of frost is relatively large. Therefore, the evaporation temperature becomes high at the end of defrosting. On the other hand, conversely, when the amount of frost is small, the air temperature rises before the evaporation temperature, and the air temperature at the end of defrosting becomes high. On the other hand, when both the air temperature and the evaporation temperature are 13 ° C. or higher, the frost adhering to the cooler 1 is completely melted regardless of the amount of frost formation, and the defrosting of the cooler 1 is performed. It can be performed reliably and the defrosting time can be shortened.

However, such a conventional device requires two temperature sensors 2 and 3, which causes a problem of high cost.

Therefore, an object of the present invention is to defrost the cooler by heating with a heater, and a temperature for detecting the defrosting end temperature while the defrosting operation can be appropriately terminated. The present invention provides a refrigerator that can reduce the number of sensors.

[0009]

In defrosting a cooler, conventionally, two temperature sensors are used in order to reliably know the defrosting end time regardless of the amount of frost formed on the cooler. I was doing. On the other hand, if the frost formation amount of the cooler can be estimated, the inventor of the present invention can detect the temperature detected by one temperature sensor based on the previously known relationship between the followability of the temperature sensor and the frost formation amount. The idea was that the defrosting termination could be controlled only by doing so. Here, the amount of frost on the cooler is affected by the high and low humidity, in other words, the amount of frost is high in the summer, such as during the rainy season, and the amount of frost is high. Conversely, the amount of frost is low in the winter. Will be less.
Then, in the refrigerator, in order to control the cooling fan of the compressor and the heater for preventing overcooling of the vegetable compartment, it is originally performed to detect the room temperature around the refrigerator. The present invention has been accomplished, paying attention to the fact that it is possible to estimate the amount of frost formed on a cooler in each season depending on the room temperature detected by the room temperature detecting means.

That is, the refrigerator according to claim 1 of the present invention comprises a cooler and a fan for blowing air through the cooler, and when the cooling operation is stopped, the cooler is heated by a heater for defrosting. It is possible to perform the defrosting operation to be performed, and an air temperature sensor for detecting an air temperature which is arranged in a portion of the cooler where a large amount of air is circulated by the fan and is easily frosted, and a refrigerator surrounding A room temperature detecting means for detecting a temperature, and a control means for controlling the end of the defrosting operation, wherein the control means detects the temperature detected by the air temperature sensor when the room temperature detected by the room temperature detecting means is equal to or higher than a predetermined temperature. When the room temperature detected by the room temperature detecting means is lower than the predetermined temperature, the temperature detected by the air temperature sensor is higher than the first temperature. And it is characterized in that it is configured to terminate defrosting operation when the above temperature.

A refrigerator according to a second aspect of the present invention comprises a cooler and a fan for blowing air through the cooler, and when the cooling operation is stopped, the cooler is heated by a heater for defrosting. A defrosting operation that can be performed, and an evaporator temperature sensor that is arranged in a portion of the cooler where the amount of air flow by the fan is small and is unlikely to form frost and that detects the temperature of the cooler, and a refrigerator The room temperature detecting means for detecting the ambient temperature, and a control means for controlling the end of the defrosting operation, the control means, by the Eva temperature sensor when the room temperature detected by the room temperature detecting means is below a predetermined temperature When the detected temperature is equal to or higher than the first temperature, the defrosting operation is terminated, and when the room temperature detected by the room temperature detecting means exceeds a predetermined temperature, the temperature detected by the evaporation temperature sensor is higher than the first temperature. And it is characterized in that it is configured to terminate defrosting operation when more than the second temperature.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment (corresponding to claim 1) of the present invention will be described below with reference to FIGS. First, FIG. 2 shows the overall configuration of the cooler 11.
This cooler 11 is arranged in a cooler chamber 12 (see FIG. 6) formed in the rear part of the refrigerator body (not shown), and forms a pipe 13 connected to the refrigeration cycle in a meandering shape and 13 is provided with a large number of fins 14. The pipe 13 includes a forward path pipe 13a on the refrigerant inlet side and a return path pipe 13b on the outlet side.
2 are arranged in parallel, and the return pipe 1
An accumulator 15 is connected to the outlet side of 3b.

As shown in FIG. 6, a fan 16 made up of a propeller fan is arranged above the cooler 11, and the cooler 11 is driven by the blowing action of the fan 16.
The air (cold air) cooled by is supplied to the freezing compartment and the refrigerating compartment, and the cold air in the freezing compartment and the refrigerating compartment is returned to the lower part of the cooler compartment 12, so that the cold air in the compartment is forced. It is circulated to.

In this case, as shown in FIG.
When rotating in the direction of arrow A, for example, the cool air in the cooler 11 part tends to be sucked into the fan 14 side as shown by the arrow B, while the cool air flows in the lower part of the cooler 11 almost uniformly, but in the upper part. As it goes to the right, it will flow toward the right side in the figure. Due to such a biased flow of air, frost adheres to the entire lower part of the cooler 11 almost uniformly, but the amount of frost tends to increase in the right side portion as compared to the left side portion toward the upper side. There is.

In the cooler chamber 12, a defrosting heater 17 composed of, for example, a glass tube heater is provided below the cooler 11, and the defrosting heater 17 causes the cooler 11 to move from below. The defrosting operation is performed by being heated. A cover 18 is provided above the defrosting heater 17 to prevent water drops falling from the cooler 11 from hitting the defrosting heater 17 during the defrosting operation. Although not shown, a well-known deodorizing member that adsorbs a malodorous component from the air in the refrigerator is attached to the lower surface of the cover 18, and the deodorizing ability of the deodorizing member is reproduced by heating during the defrosting operation. Will be held together.

The cooler 11 is provided with an air temperature sensor 19 used to control the end of the defrosting operation. The air temperature sensor 19 is composed of, for example, a thermistor, and is mounted via the holder 20 on the upper right side of the cooler 11, that is, in the vicinity of a portion where a large amount of cold air is circulated by the fan 16 and frost easily forms. . At this time, the holder 20 is made of a heat insulating material, and is configured so that the temperature sensor 19 and the cooler 11 are not in thermal contact when the air temperature sensor 19 is fixed as shown in FIG. ing. With this, this air temperature sensor 1
9 is adapted to detect the air temperature (air temperature) in the vicinity of a portion of the cooler 11 where frost is likely to form.

FIG. 4 shows an outline of an electrical structure related to the defrosting control of the cooler 11. The control circuit 21, which is a control means, is mainly composed of a microcomputer, and is adapted to receive an air temperature detection signal from the air temperature sensor 19, and at the same time, the defrost heater 17 and the compressor of the refrigeration cycle. It is designed to control the disconnection of 22. Furthermore, this control circuit 21
A room temperature detection signal from a room temperature sensor 23, which is a room temperature detecting means, is input to the. This room temperature sensor 2
3 is arranged in, for example, a control circuit accommodating portion provided on the upper rear surface side of the refrigerator main body, and detects the ambient temperature (room temperature) of the refrigerator main body. The detection signal of the room temperature sensor 23 is used for controlling the cooling fan of the compressor 22 and for controlling the heater for preventing the vegetable room overcooling.

Due to its software configuration, the control circuit 21 starts the defrosting operation on the condition that the cumulative operating time of the compressor 22 reaches a predetermined time, and the air temperature sensor 19 and the room temperature sensor 23 The defrosting operation is ended based on the signal of. At this time, as will be described in detail later in the description of the operation, in the control circuit 21, when the temperature detected by the room temperature sensor 23 is equal to or higher than a predetermined temperature (for example, 12 ° C.), the temperature detected by the air temperature sensor 19 is the first temperature. (Eg 13
When the temperature detected by the room temperature sensor 23 is lower than a predetermined temperature, the temperature detected by the air temperature sensor 19 is a second temperature higher than the first temperature (for example, 15 ° C.). It is configured to end the defrosting operation at the above time.

Next, the operation of the above configuration will be described with reference to FIGS. FIG. 1 shows a flowchart of the control of the defrosting operation. When the defrosting operation is started on the condition that the cumulative operation time of the compressor 22 has reached the predetermined time, first, in step S1, the compressor 22 is de-energized and the defrost heater 17 is energized. As a result, the cooler 11 is heated and the attached frost is melted.
Then, along with this, the temperature detected by the air temperature sensor 19 rises. In step S2, it is determined whether or not the temperature detected by the air temperature sensor 19 reaches the first temperature of 13 ° C., and if it reaches (YES), the process proceeds to step S3.

In step S3, it is determined whether or not the temperature detected by the room temperature sensor 23 is 12 ° C. or higher, which is a predetermined temperature. If it is 12 ° C. or higher (YES), the compressor 22 is energized in step S4. At the same time, the defrosting heater 17 is cut off and the defrosting operation ends. On the other hand, when the temperature detected by the room temperature sensor 23 is lower than 12 ° C. in step S3 (NO), the process proceeds to step S5. Then, in step S5, it is determined whether or not the temperature detected by the air temperature sensor 19 reaches the second temperature of 15 ° C., and if it reaches (YE
S) In step S4, the compressor 22 is energized and the defrost heater 17 is turned off to end the defrost operation.

Here, even when the defrosting operation is started under the same condition (accumulated operation time of the compressor 22), the frost formation amount of the cooler 11 may change due to moisture in the air, etc. Among the above, the temperature detected by the air temperature sensor 19 that detects the air temperature of the portion where the amount of frost is relatively large exhibits a temperature followability according to melting of frost when the amount of frost of the cooler 11 is large. On the other hand, when the frost amount of the cooler 11 is small, it is easily affected by the heat from the defrost heater 17,
The frost may rise before it has completely melted. However, the amount of frost formed on the cooler 11 is affected by high and low humidity. In other words, the amount of frost is high in the summer such as during the rainy season and the amount of frost is large, and conversely, in the low winter, the amount of frost is large. Also less. Therefore, the room temperature sensor 23
According to the room temperature detected by, the season, that is, the amount of frost formation can be estimated.

According to the research by the present inventor, the air temperature sensor 1 when the frost adhering to the cooler 11 is completely removed
9 shows the relationship between the detected temperature, that is, the air temperature at the end of defrost (defrost end temperature) and the room temperature (the temperature detected by the room temperature sensor 23), as shown in FIG. From the figure, when the room temperature is 5 ° C., the defrosting end temperature is about 15 ° C., which decreases as the room temperature rises, and when the room temperature rises above 12 ° C., the defrosting end temperature becomes about 13 ° C. regardless of the room temperature. I knew that.

Therefore, according to this embodiment, the frosting amount differs depending on the room temperature, and the defrosting end temperature differs depending on the frosting amount. Since the defrosting end temperature is made different by
It is possible to execute the defrosting operation relatively corresponding to the amount of frost formed on the cooler 11, and it is possible to end the defrosting operation at an appropriate time, and prevent the defrosting operation time from being unnecessarily long. Moreover, in this case, by using the room temperature sensor 22 which has been conventionally used for controlling the operation of the refrigerator, the cooler 11 is provided with one temperature sensor unlike the conventional one which requires the two temperature sensors 2 and 3. The end time of the defrosting operation can be determined simply by providing the individual temperature sensors 19,
The cost can be reduced.

7 to 10 show a second embodiment (corresponding to claim 2) of the present invention. The second embodiment is different from the first embodiment in that an air temperature sensor 31 is provided in the cooler 11 instead of the air temperature sensor 19, and a software configuration of the control circuit 21. . Therefore, other parts are common to the first embodiment, and detailed description thereof will be omitted and reference numerals will be used in common, and only different points will be described below.

As shown in FIGS. 7 and 8, the cooler 11
On the left side of the drawing, a mounting recess 32 is formed by curving the upper part of the left side surface inward. For example, the EVA temperature sensor 31 formed of a thermistor is mounted by the mounting member 33 in a state of being fitted into the mounting recess 32. Has been. At this time, the mounting member 33 is made of a metal having good thermal conductivity, and therefore the evaporation temperature sensor 31 is in thermal contact with the cooler 11 on the entire outer peripheral surface thereof, and the fan 1 of the cooler 11 is in contact therewith.
The temperature (evaporation temperature) of the portion where the circulation amount of cold air due to 6 is small and frost is unlikely to occur is directly detected.

When the temperature detected by the room temperature sensor 23 is equal to or lower than the predetermined temperature (12 ° C.), the control circuit 21 serving as the control means detects the temperature detected by the evaporation temperature sensor 31 equal to or higher than the first temperature (13 ° C. in this case). Finish the defrosting operation,
When the temperature detected by the room temperature sensor 23 exceeds a predetermined temperature, the defrosting operation is terminated when the temperature detected by the evaporation temperature sensor 31 is equal to or higher than the second temperature (17 ° C. in this case).

That is, as shown in FIG. 9, when the defrosting operation control is started, first, in step S6, the compressor 2 is operated.
2 is cut off and the defrost heater 17 is energized. As a result, the cooler 11 is defrosted and the temperature detected by the evaporation temperature sensor 31 rises. In step S7, it is determined whether or not the temperature detected by the evaporation temperature sensor 22 reaches 13 ° C., and if it reaches (YES), the process proceeds to step S8. In step S8, it is determined whether the temperature detected by the room temperature sensor 23 is 12 ° C. or lower, and if it is 12 ° C. or lower (YE
S), in step S9, the compressor 22 is energized, the defrost heater 17 is turned off, and the defrost operation ends.
On the other hand, in step S8, the temperature detected by the room temperature sensor 23 is 12
If the temperature exceeds ° C (NO), the process proceeds to step S10. Then, in step S10, it is determined whether or not the temperature detected by the evaporator temperature sensor 31 reaches 17 ° C., and if it reaches (YES), the compressor 22 is energized in step S9, and the defrost heater 17 is deenergized to remove electricity. Finish frost operation.

In contrast to the temperature detected by the air temperature sensor 19 of the first embodiment, the temperature detected by the evaporator temperature sensor 31 is opposite to the temperature detected by the air temperature sensor 19, and if the amount of frost formed on the cooler 11 is small, the frost will melt. In contrast to the temperature followability, the amount of frost tends to increase before the frost is completely melted when the amount of frost is large. Also in this case, the amount of frost formation can be estimated from the room temperature detected by the room temperature sensor 23, as in the first embodiment.

According to the research conducted by the present inventor, the evaporation temperature sensor 3 when the frost attached to the cooler 11 is completely removed
The detected temperature of 1, that is, the relationship between the temperature of the cooler 11 at the end of defrost (defrost end temperature) and the room temperature is as shown in FIG. From the figure, when the room temperature is 5 ° C, the defrosting end temperature is about 13 ° C, which is substantially constant until the room temperature reaches 12 ° C, and gradually rises when the room temperature exceeds 12 ° C, and the room temperature rises to 30 ° C.
It was found that the defrosting end temperature at 0 ° C was about 17 ° C.

Therefore, also in the case of the present embodiment, as in the case of the first embodiment, when the room temperature is 12 ° C. or lower, the frosting amount differs depending on the room temperature, and the defrosting ending temperature differs depending on the frosting amount. Since the defrosting end temperature is set to be different when the temperature exceeds 12 ° C., it is possible to perform the defrosting operation relatively corresponding to the frost formation amount of the cooler 11 and perform the defrosting operation at an appropriate time. It can be ended, and the defrosting operation time can be prevented from being unnecessarily long. Moreover, also in this case, one temperature sensor 3 is provided in the cooler 11 by using the room temperature sensor that has been conventionally used for controlling the operation of the refrigerator.
Only by providing 1, the end time of the defrosting operation can be determined, and the cost can be reduced.

[0031]

As described above, according to the present invention, the cooler is provided with only one temperature sensor, and the end time of the defrosting operation is determined based on the detected temperature of this temperature sensor and the detected temperature of the room temperature sensor. At this time, the defrosting end temperature is set to be different when the room temperature is high and when the room temperature is low, so that the defrosting operation can be relatively short. Further, unlike the conventional case, it is not necessary to provide two temperature sensors in the cooler, and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a flowchart showing a first embodiment of the present invention and showing a control procedure during a defrosting operation.

FIG. 2 is a perspective view showing a configuration of a cooler portion.

FIG. 3 is an enlarged exploded perspective view of an air temperature sensor and a holder.

FIG. 4 is a block diagram of an electrical configuration related to defrosting operation.

FIG. 5 is a diagram showing the relationship between the defrosting end temperature and room temperature.

FIG. 6 is a diagram showing a flow of cool air in a cooler portion by a blowing action of a fan.

FIG. 7 is a view corresponding to FIG. 2 showing a second embodiment of the present invention.

FIG. 8 is a diagram corresponding to FIG. 3;

FIG. 9 is a diagram corresponding to FIG. 1;

FIG. 10 is a diagram corresponding to FIG. 5;

FIG. 11 is a diagram corresponding to FIG. 2 showing a conventional example.

FIG. 12 is a view equivalent to FIG.

FIG. 13 is a view corresponding to FIG.

[Explanation of symbols]

Reference numeral 11 is a cooler, 16 is a fan, 17 is a defrost heater (heater), 19 is an air temperature sensor, 21 is a control circuit (control means), 23 is a room temperature sensor (room temperature detection means), and 31 is an evaporator temperature sensor. .

Claims (2)

[Claims] 1. A cooler and a fan that blows air through the cooler, and is capable of performing a defrosting operation for defrosting by heating the cooler with a heater while the cooling operation is stopped. In the air conditioner, an air temperature sensor for detecting an air temperature, which is arranged in a portion where a large amount of air is blown by the fan and is likely to form frost, a room temperature detecting unit for detecting a temperature around a refrigerator, and the defrosting operation. Control means for controlling the end of the, the control means performs a defrosting operation when the temperature detected by the air temperature sensor is equal to or higher than a first temperature when the room temperature detected by the room temperature detection means is equal to or higher than a predetermined temperature. When the room temperature detected by the room temperature detecting means is lower than the predetermined temperature, the defrosting operation is ended when the temperature detected by the air temperature sensor is equal to or higher than the second temperature which is higher than the first temperature. Refrigerator, characterized in that it is configured to. 2. A cooler and a fan that blows air through the cooler, and is capable of performing a defrosting operation in which defrosting is performed by heating the cooler with a heater while the cooling operation is stopped. In, in the cooler, an air temperature sensor for detecting the temperature of the cooler, which is arranged in a portion where the amount of air flow by the fan is small and is unlikely to form frost, and a room temperature detecting means for detecting the temperature around the refrigerator; A control means for controlling the end of the defrosting operation, wherein the control means removes when the room temperature detected by the room temperature detecting means is lower than or equal to a predetermined temperature and when the temperature detected by the evaporation temperature sensor is higher than or equal to a first temperature. When the frost operation is terminated and the room temperature detected by the room temperature detecting means exceeds a predetermined temperature, the defrosting operation is performed when the temperature detected by the evaporation temperature sensor is equal to or higher than the second temperature higher than the first temperature. Refrigerator, characterized in that it is configured to terminate.