JPH08338679A - Refrigerator - Google Patents

Abstract

PURPOSE: To detect dew condensation with high accuracy in an early time and reduce energy consumption required for drip-removal or moisture- condensation prevention. CONSTITUTION: There are provided a moisture sensor 6a which is laid out in a partition area 1a of a casing 1 adjacent to a freezer compartment 4 or the like so as to detect dew condensation and a heating means which removes drips and prevents moisture condensation and a control means which controls the heating means based on the output of the moisture sensor 6a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerator, and more particularly to a technique for preventing dew condensation.

[0002]

2. Description of the Related Art As a conventional refrigerator provided with a dew protection measure, there is, for example, one shown in FIGS.
Since the inside of the refrigerator is cooled, dew condensation is likely to occur especially near the gasket on the refrigerator body side with which the door abuts. On the other hand, in this conventional example, a part of the pipe 2 on the high pressure (high temperature) side in the refrigeration cycle is attached to the door contact surface on the refrigerator main body 21 side.
When the refrigerating cycle is in operation, 2 is heated and the periphery of the door contact surface is heated to prevent dew condensation. An electric heater (not shown) is also used for this, and when the refrigeration cycle is stopped, the electric heater is energized to reduce the temperature around the door contact surface.

[0003]

Conventionally, the surrounding environment,
In particular, without knowing the temperature and humidity, the energization control etc. to the electric heater were always performed on the safety side assuming high temperature and high humidity. For this reason, power was consumed more than necessary unless the temperature and humidity were high. In most of the air-conditioned rooms in recent years, this is the case where the temperature and humidity are not such high, so there has been a demand for a dew-proof and dew-draining technology that consumes less power.

The present invention has been made in view of the above circumstances, and it is possible to prevent malfunction of the dew condensation sensing portion, accurately detect dew condensation early and reduce energy consumption required for dew condensation or dew condensation prevention. The purpose is to provide.

[0005]

In order to solve the above-mentioned problems, the invention according to claim 1 is arranged in a partition portion, a wall surface portion or a door portion of a housing adjacent to a freezing chamber, and humidity for detecting dew condensation. The gist of the present invention is to have a sensor, a heating unit that removes or prevents dew condensation, and a control unit that controls the input of the heating unit based on the output of the humidity sensor.

A second aspect of the present invention provides the refrigerator according to the first aspect, wherein the sensing portion of the humidity sensor is opened downward.

According to a third aspect of the present invention, in the refrigerator according to the first aspect, the humidity sensor is configured to update the zero point by setting the output at the time of the completion of the dew payment to zero humidity. And

According to a fourth aspect of the present invention, in the refrigerator according to the first aspect, the control means makes an appropriate notification when the output of the humidity sensor exceeds a predetermined value at the completion of the dew payment. The gist is that it is configured as.

According to a fifth aspect of the present invention, in the refrigerator according to the first aspect, the control means determines that the time when the decrease in the output of the humidity sensor is stopped by the heating of the heating means is just before the completion of the dew payment. Then, after that, the heating by the heating means is performed for a certain period of time, and when the certain period of time elapses, it is determined that the dew removal is completed.

According to a sixth aspect of the present invention, in the refrigerator according to the first aspect, the control unit stores in advance an upper limit output time change rate of the humidity sensor, and the output time change rate of the humidity sensor is the upper limit. The gist is that the configuration is such that when the output time change rate is exceeded, it is determined as wetness other than dew condensation.

According to a seventh aspect of the present invention, in the refrigerator according to the sixth aspect, the heating means includes a humidity sensor heating means for heating the humidity sensor and another heating means. When the control means determines that the wetness has occurred, the humidity sensor heating means is operated until the humidity sensor detects the completion of dew removal, and the other heating means is operated for a predetermined time. The gist is that it is configured to judge that the humidity sensor is initialized.

According to an eighth aspect of the present invention, in the refrigerator according to the first aspect, the control means detects dew drop from a sudden decrease in the output increase after the dew condensation is detected by the output of the humidity sensor. The gist is that the heating means is operated from the time when the dew drop is detected.

According to a ninth aspect of the present invention, there is provided a thermosiphon-type dew-proof pipe in which the vicinity of a door contact surface including a partition portion of a casing adjacent to a freezer compartment is set to a low temperature side and a compressor is set to a high temperature side. A humidity sensor that detects condensation or dew near the door contact surface, a heating unit provided on the dew-proof pipe near the compressor, and the heating unit when dew or condensation is detected by the humidity sensor. It is a gist to have a control means to operate.

According to a tenth aspect of the present invention, in the refrigerator according to the ninth aspect, the heat exchange points in the dew-proof pipe with the compressor and the heating means are located at a position higher than the bottom of the dew-proof pipe. The main point is to set.

[0015]

According to the invention of claim 1, the dew condensation is detected early by arranging the humidity sensor in the partition part, wall surface part or door part of the housing adjacent to the freezing room where dew condensation is likely to occur, and dew condensation is required. When the dew condensation is detected, the energy consumption required for the dew payment can be reduced by making an input to the heating means.

According to the second aspect of the present invention, by opening the sensing unit of the humidity sensor downward, liquid condensation from the front of the refrigerator, liquid dripping from the door, etc. does not enter the sensing unit, and this is the dew condensation sensing unit. The sensitivity deterioration or malfunction of the humidity sensor is prevented.

In the third aspect of the present invention, the humidity sensor updates the zero point by setting the output at the time of the completion of dew payment to zero humidity, and the output offset amount due to dirt on the sensor surface is compensated for, and the dew condensation is accurate. Detected.

In the invention according to claim 4, the control means prompts the user to perform maintenance of the humidity sensor by appropriately notifying when the output of the humidity sensor exceeds a predetermined value when the dew payment is completed. A malfunction due to an infinite increase in the zero point offset is prevented.

In the invention according to claim 5, the control means determines that the time when the decrease in the output of the humidity sensor is stopped by the heating of the heating means is just before the completion of the dew removal, and then the heating by the heating means is kept constant. By performing the operation for a certain period of time and determining that the dew removal has been completed when this fixed time has elapsed, it is possible to prevent the dew remaining and perform a reliable dew application.

In the invention according to claim 6, the control means stores in advance the upper limit output time change rate of the humidity sensor, and when the output time change rate of the humidity sensor exceeds the upper limit output time change rate, other than dew condensation. When it is determined that the humidity sensor is wet with water, it is possible to prompt the user for maintenance with an alarm or the like, and it is possible to prevent malfunction of the humidity sensor.

In the invention described in claim 7, when the control means determines that the above-mentioned wetting has occurred, the humidity sensor heating means is operated until the humidity sensor detects the completion of the dew removal, and the other heating means is set to a predetermined temperature. By determining that the humidity sensor is initialized after being operated for a certain period of time, it is possible to remove the wetness and automatically restore the humidity sensor when an abnormality due to the wetness other than dew condensation occurs.

In the eighth aspect of the present invention, by operating the heating means from the time when the dew drop is detected, an energy-saving operation mode in which a small amount of dew condensation is allowed is realized.

In the invention according to claim 9, the vicinity of the door contact surface including the partition portion of the housing adjacent to the freezer compartment is on the low temperature side,
A thermosiphon-type dew-proof pipe with the compressor on the high temperature side is provided, and a humidity sensor that detects dew condensation or drip near the door abutment surface is also provided, and heating means is provided on the dew-proof pipe near the compressor. Is provided, and by operating the heating means when dew condensation or dew drop is detected by the humidity sensor, it is possible to reliably perform dew payment even at low room temperature.

According to the tenth aspect of the present invention, the heat exchange points of the compressor and the heating means in the dew proof pipe are set at positions higher than the bottom of the dew proof pipe, so that The working fluid efficiently circulates in one direction, the heat transfer effect is improved, and reliable dew removal is performed.

[0025]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 8 are views showing a first embodiment of the present invention. The first embodiment will be sequentially described as first to eighth embodiments corresponding to each claim.

Example 1 will be described with reference to FIGS. 1 to 3. In FIG. 1, reference numeral 1 is a casing, 2 is a door, and the casing 1 is roughly divided into four chambers, and a refrigerating chamber 3 (average temperature is approximately + 3 ° C.) and a first freezing chamber 4a (the same as above, (About -20 ° C), the second freezing chamber 4b (the same, about -20 ° C), and the vegetable compartment 5 (the same, about + 5 ° C). Hereinafter, the first freezing chamber 4a and the second freezing chamber 4b are collectively referred to as the freezing chamber 4. Since the inside of the refrigerator is cooled, the horizontal partition plate 1 of the housing 1 adjacent to the freezer compartment 4 where the temperature becomes particularly low
Condensation is likely to occur on a, the wall surface or the door 2. In this embodiment, humidity sensors 6a and 6b, which are dew condensation sensing parts, are provided on the horizontal partition plate 1a where dew condensation easily occurs and on the lower surface 2a of the door 2 as shown in FIG. Thus, two humidity sensors 6a and 6b are provided in the figure, but either one of them or the drawer door of the freezer compartment 4 may be incorporated. However, if it is installed in the drawer door, a cable for exchanging signals with the main body side is required, which may deteriorate usability. In addition, a dew-proof heater 7 as a heating means for removing dew or preventing dew is installed in the same portion where dew condensation is likely to occur as described above. In the figure, a first heater 7a is arranged around the humidity sensor 6b on the lower surface 2a of the door 2 as a dew-proof heater, and a second heater 7b is arranged immediately adjacent thereto (FIG. 2).
FIG. 3 shows a control system of the dew-proof heater 7. The detection signal of the humidity sensor 6 is input to the control unit 8 as a control means, the switching element 9 is turned on by the control signal from the control unit 8 based on the detection signal, the relay 10 is activated, and the power source 11 causes the dew-proof heater. The required electric power is input to 7. The first heater 7a and the second heater 7b in FIG. 2 are connected to the relay 1 by a control signal from the control unit 8.
Each is controlled via 0a and 10b.

Next, the operation of this embodiment will be described. By arranging the humidity sensors 6a and 6b in the portion of the horizontal partition plate 1a and the door 2 of the housing 1 which are adjacent to the freezing chamber 4 where dew is likely to occur, dew condensation is detected at an early stage, and the humidity sensor 6a,
When the output of 6b exceeds a certain value, the dew-proof heater 7 is input by the control signal from the control unit 8, so that the dew-dropping can be executed at an early stage.

As described above, according to this embodiment, it is possible to reduce unnecessary power consumption for performing the dewdrop operation only when the refrigerator is requested to dew.

Example 2 will be described with reference to FIG. The humidity sensor 6 has a laminated structure in which an electrode 13, a water-absorbing polymer 14 and a breathable filter 15 are sequentially stacked on a substrate 12, and as shown in FIG. It is attached to the required part of the refrigerator so that it opens. Then, the molecules of water vapor are adsorbed by the water-absorbing polymer 14 through the breathable filter 15, the change in capacitance at that time is converted into a change in voltage and output, and the change in relative humidity is detected from the change in this output. Has become.

As described above, according to this embodiment, since the sensitive portion of the humidity sensor 6 is opened downward, the liquid is not scattered from the front of the refrigerator, the liquid dripping from the door 2 or the like does not enter the sensitive portion. It is possible to prevent sensitivity deterioration or malfunction of the sensor 6.

Example 3 will be described with reference to FIG. When the compressor is stopped in the refrigeration cycle, the output of the humidity sensor 6 gradually increases. When the output exceeds a predetermined threshold value, electric power is applied to the dew-proof heater 7 by a control signal from the control unit 8 to perform dew payment. If the surface of the humidity sensor 6 is contaminated for some reason during this dew removal operation, its output remains as an offset even if the humidity in the vicinity of the humidity sensor 6 becomes zero. At this time, when it is detected that the output does not change for a certain period of time while the dew-proof heater 7 is energized, the humidity is set to zero and the zero point is updated. As a result, the output offset amount due to dirt on the sensor surface is compensated, and the dew condensation can be detected accurately.

Example 4 Similar to the above, description will be made with reference to FIG. In the fourth embodiment, when it is recognized that the updated zero point exceeds the constant output value V _x , the humidity sensor 6 is activated by an alarm to the user.
Encourage maintenance. This prevents malfunction due to the zero point offset of the humidity sensor 6 increasing infinitely.

Example 5 will be described with reference to FIG. When the dew condensation heater 7 heats when the dew condensation is detected and the decrease in the output value of the humidity sensor 6 is zero (ΔV / Δt = 0), it is recognized as “immediately before the completion of dew removal”. After that, the power is applied to the dew-proof heater 7 for a fixed time T, and when the time has elapsed, it is recognized as "completion of dew-dropping". Depending on the conditions of the installation location of the refrigerator in the home,
Even if the output value of the humidity sensor 6 indicates zero, there is a possibility that a small amount of dew remains. However, by energizing the dew-proof heater 7 for a certain period of time T, it is possible to reliably remove this residual amount. The fixed time T is obtained in advance by experiments or the like.

Example 6 will be described with reference to FIG. This figure shows the output characteristic of the humidity sensor 6 when the compressor is stopped. Although the output characteristics at high temperature (a), normal time (b), and low temperature (c) are shown in the figure, the control unit 8 outputs at least the output time at high temperature (a). The change rate (ΔV ₃ / Δt ₃ ) is stored in advance as the upper limit output time change rate. As shown by the broken line in the figure, when the humidity sensor 6 is splashed with water, the rate of change in output time greatly exceeds the rate of change in upper limit output time. We recognize that this is wetting with water other than condensation.

Since the refrigerator is often used around water, it is expected that the humidity sensor 6 gets wet with water or the like.
In the present embodiment, by correctly recognizing this, it is possible to prompt the user for maintenance with an alarm or the like. Also, if there is an automatic return function, it is possible to know when to execute it. As a result, malfunction of the humidity sensor 6 can be prevented.

Embodiment 7 When the controller 8 detects wetting in the above Embodiment 6, first, the humidity sensor 6 is initialized by the first heater 7a as the humidity sensor heating means. The energization control is performed until the zero point is recognized, that is, until the completion of the exposure payment is detected. Since it is not possible to recognize how much dew is attached to other places, the second heater 7b is energized for a predetermined "sufficient time to completely remove the dew condensation". As a result, in the event of an abnormality due to wetting other than dew condensation, the wetting can be removed and the humidity sensor 6 can be automatically restored.

Example 8 Using FIG. 7, the sensor output characteristic at high humidity (a)
Will be described as an example. The output of the humidity sensor 6 increases,
Condensation begins when the relative humidity exceeds 100%. After that, the output of the humidity sensor 6 increases due to the adhesion of water droplets. When the dew grows and drops, the output sharply decreases, as indicated by d in the figure. This is recognized as "drip", and the dew-proof heater 7 is energized when this drip is detected. This makes it possible to realize an operation mode in which the dew-proof heater 7 is not energized when a small amount of dew appears, but the dew condensation starts to be detected and then energized, and more power-saving operation can be selected according to the user's preference. Becomes

Next, the control operation of the dew-proof heater 7 by the control unit 8 through the above-described first to eighth embodiments will be described with reference to the flowchart of FIG. With no input to the dew-proof heater 7 (step 101), it is determined whether the output time change rate of the humidity sensor 6 is larger than the upper limit output time change rate (step 102). When it is large, it is recognized that it is wet with water other than dew condensation (step 103), and the user is urged to maintain the humidity sensor 6 by an alarm or the like without any input to the dew-proof heater 7 (steps 104, 1).
05). When the output time change rate is smaller than the upper limit output time change rate, it is determined whether or not dew condensation (or wetting) has occurred from the output of the humidity sensor 6 (step 106). When it is recognized that dew condensation (or wetting) has occurred, input is made to the dew-proof heater 7 (step 107), and it is determined whether or not the decrease in the output of the humidity sensor 6 has become zero (step 10).
8). When the decrease in the output is zero, it is determined that the dew removal is just completed (step 109), and the power application to the dew-proof heater 7 is continued for a certain time T (step 11).
0). It is determined whether or not the output value of the humidity sensor 6 after the power application is continued for a certain time T exceeds a specified value V _x (step 111). When it exceeds the limit, the input to the dew-proof heater 7 is turned off, and the user is prompted by an alarm to perform maintenance of the humidity sensor 6 (steps 112 and 11).
3). When it does not exceed the specified value V _x , the output value at that time is set to zero and the zero point is updated (step 11).
4). Then, it is determined that the dew payment is completed (step 11).
5). The above-described control of the dew-proof heater 7 is performed independently of the control of the refrigeration cycle.

9 and 10 show a second embodiment of the present invention. It should be noted that the second embodiment will be sequentially described as Embodiments 9 and 10 corresponding to each claim, as in the above.

Example 9 will be described with reference to FIGS. 9 and 10. In this embodiment, a thermosiphon-type dew-proof function that uses the heat of the compressor is used. That is, as shown in FIG. 9, a thermosiphon-type dew-preventing pipe 17 is provided in which the vicinity of the door contact surface including the partitioning portion of the housing adjacent to the freezer compartment is set to the low temperature side and the compressor 16 is set to the high temperature side. , Its dew-proof pipe 17
A heater 18 as a heating means is provided near the upper compressor 16. Further, the same humidity sensor as in the first embodiment and a controller for controlling the operation of the heater 18 are also provided. The operation of this embodiment at a high room temperature (about 20 ° C. or higher) and at a low room temperature (about 20 ° C. or lower) will be described with reference to FIGS. At high room temperature ((a) in the figure), the surface temperature of the compressor 16 is high, and even when the compressor 16 is stopped, the dew pipe 17, which is a thermosiphon, is sufficiently heated by the residual heat to operate, and the input to the heater 18 is performed. Without it, the dew protection function is maintained from beginning to end. At low room temperature ((b) in the figure), the surface temperature of the compressor 16 becomes low, and the working fluid in the dew proof pipe 17 does not circulate sufficiently. For this reason, dew is likely to occur in the section d in the figure. Therefore, in this case, when the dew condensation or dew drop is detected by the humidity sensor (from the starting point of d in the figure), the dew-proof function is generated by inputting to the heater 18.

Example 10 will be described with reference to FIG. The location of heat exchange with the compressor 16 and the location of heat exchange with the heater 18 in the dew proof pipe 17 are set to a position higher than the bottom 17a of the dew proof pipe 17. As a result, the working fluid in the dew proof pipe 17 efficiently circulates in one direction, the heat transfer effect is improved, and a reliable dew proof function is obtained.

[0042]

As described above, according to the first aspect of the present invention, a humidity sensor for detecting dew condensation, which is arranged in a partition portion, a wall surface portion or a door portion of a housing adjacent to a freezer compartment, A heating means that removes or prevents dew condensation
Since the control means for controlling the input of the heating means on the basis of the output of the humidity sensor is provided, dew condensation is detected at an early stage, and the dew condensation is required by inputting to the heating means at the time of dew condensation detection. Energy consumption required for can be reduced.

According to the second aspect of the present invention, since the sensing unit of the humidity sensor is opened downward, liquid condensation from the front of the refrigerator, liquid dripping from the door, etc. does not enter the sensing unit and the dew condensation sensing unit. The sensitivity deterioration or malfunction of the humidity sensor can be prevented, and dew condensation can be detected early and accurately.

According to the third aspect of the present invention, the humidity sensor is configured to update the zero point by setting the output at the time of the completion of the exposure payment to zero humidity, so that the output offset amount due to dirt on the sensor surface is compensated. As a result, dew condensation can be detected accurately.

According to the fourth aspect of the invention, the control means is configured to give an appropriate notice to the user when the output of the humidity sensor exceeds a predetermined value at the time of completion of the exposure payment. It is possible to promote maintenance of the humidity sensor and prevent malfunction due to the zero point offset increasing infinitely.

According to the fifth aspect of the present invention, the control means determines that the time when the decrease in the output of the humidity sensor is stopped by the heating of the heating means is just before the completion of the dew removal, and then the heating is performed. Since the heating is performed by the means for a fixed time and it is determined that the dew removal is completed when the predetermined time elapses, the dew remaining can be prevented and the dew can be reliably performed.

According to the sixth aspect of the present invention, the control means stores in advance the upper limit output time change rate of the humidity sensor, and the output time change rate of the humidity sensor exceeds the upper limit output time change rate. Since the time is determined to be wet other than dew condensation, malfunction of the humidity sensor can be prevented by prompting the user for maintenance with an alarm or the like.

According to the invention of claim 7, the heating means comprises a humidity sensor heating means for heating the humidity sensor and another heating means, and the control means comprises the wetting means. When it is determined that the humidity sensor heating means is operated until the completion of dew payment is detected by the humidity sensor, and the other heating means is operated for a predetermined time, and then the humidity sensor is initialized. Since it is configured to determine that the humidity sensor is in an abnormal state due to wetting other than dew condensation, it is possible to remove the wetting and automatically return the humidity sensor.

According to the eighth aspect of the present invention, the control means detects the dew drop from the sudden decrease in the output increase after the dew drop is detected by the output of the humidity sensor. Since the heating means is configured to operate, it is possible to realize an energy-saving operation mode in which some initial dew condensation is allowed.

According to the ninth aspect of the present invention, the vicinity of the door contact surface including the partition of the housing adjacent to the freezer compartment is on the low temperature side,
A thermosiphon-type dew-proof pipe configured with the compressor on the high temperature side, a humidity sensor for detecting dew condensation or dew drop near the door contact surface, and heating means provided on the dew-proof pipe near the compressor. And, since the humidity sensor is provided with a control means for operating the heating means when dew condensation or dew drop is detected, when a thermosiphon-type dew-proof pipe is provided as the dew-proof function section, at low room temperature. Can certainly make dew payment.

According to the tenth aspect of the present invention, the heat exchange points of the compressor and the heating means in the dew-proof pipe are set at positions higher than the bottom of the dew-proof pipe. The working fluid therein efficiently circulates in one direction, the heat transfer effect is improved, and reliable dew removal can be performed.

[Brief description of drawings]

FIG. 1 is a front view showing a state in which a door is opened in a first embodiment of a refrigerator according to the present invention.

FIG. 2 is a diagram showing an installation example of a humidity sensor and a heating means in the first embodiment.

FIG. 3 is a diagram showing a control system of a heating means in the first embodiment.

FIG. 4 is an exploded perspective view of the humidity sensor according to the first embodiment.

FIG. 5 is a diagram showing sensor output characteristics for explaining the zero point update of the humidity sensor in the first embodiment.

FIG. 6 is a diagram showing sensor output characteristics for explaining the completion of exposure payment in the first embodiment.

FIG. 7 is a diagram showing sensor output characteristics for explaining wetness detection and the like in the first embodiment.

FIG. 8 is a flow chart for explaining a control action of the humidity sensor in the first embodiment.

FIG. 9 is a diagram showing a thermosiphon-type dew-proof pipe structure according to the second embodiment of the present invention.

FIG. 10 is a diagram for explaining the operation of the second embodiment.

FIG. 11 is a view showing a dew-proof structure in a conventional refrigerator.

FIG. 12 is a diagram showing a refrigeration cycle in the conventional example.

[Explanation of symbols]

 1 Case 1a Horizontal Partition Plate 2 Door 4 Freezer Chamber 6, 6a, 6b Humidity Sensor 7, 7a, 7b Dew-proof Heater (Warming Means) 8 Controller (Control Means) 16 Compressor 17 Dew-proof Pipe 17a Dew-proof Pipe Bottom part 18 heater (heating means)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuko Hongo 8 Shinsita-cho, Isogo-ku, Yokohama-shi, Kanagawa, Ltd. Inside Toshiba Living Space Systems Engineering Laboratory (72) Inventor, Atsushi Kusunoki 8 Shinsugita-cho, Isogo-ku, Yokohama, Kanagawa Address Company Incorporated in Toshiba Living Space Systems Engineering Laboratory (72) Inventor Kosaku Adachi 8 Shinsita-cho, Isogo-ku, Yokohama-shi, Kanagawa Incorporated in Toshiba Living Systems Engineering Laboratory (72) Incorporator Keiaki Asakura Shimbashi, Minato-ku, Tokyo 3-3-9 Toshiba Abu E Co., Ltd.

Claims (10)

[Claims] 1. A humidity sensor, which is arranged on a partition part, a wall surface part or a door part of a housing adjacent to a freezing compartment, detects dew condensation, and a heating means for dew condensation or preventing dew condensation.
And a control unit that controls the input of the heating unit based on the output of the humidity sensor. 2. The refrigerator according to claim 1, wherein the sensitive portion of the humidity sensor is opened downward. 3. The refrigerator according to claim 1, wherein the humidity sensor is configured to update the zero point by setting the output at the time of completion of the exposure payment to zero humidity. 4. The control means is configured to give an appropriate notification when the output of the humidity sensor exceeds a predetermined value at the time of completion of the exposure payment. refrigerator. 5. The control means determines when the output of the humidity sensor has stopped decreasing due to the heating of the heating means, immediately before the completion of the dew removal, and then performs the heating by the heating means for a certain period of time. The refrigerator according to claim 1, wherein the refrigerator is configured to determine that the dew payment is completed when the predetermined time has elapsed. 6. The control unit stores the upper limit output time change rate of the humidity sensor in advance, and judges that the output time change rate of the humidity sensor exceeds the upper limit output time change rate as wetness other than dew condensation. The refrigerator according to claim 1, wherein the refrigerator is configured to. 7. The heating means comprises a humidity sensor heating means for heating the humidity sensor and another heating means,
When the control means determines that the wetness has occurred, the humidity sensor heating means is operated until the humidity sensor detects the completion of dew removal, and the other heating means is operated for a predetermined time. 7. The refrigerator according to claim 6, wherein the refrigerator is configured to determine that the humidity sensor is initialized. 8. The control means detects a dew drop from a sudden decrease in the output increase after the dew condensation is detected by the output of the humidity sensor, and operates the heating means from the time of detecting the dew drop. The refrigerator according to claim 1, wherein the refrigerator is configured as follows. 9. A thermosiphon-type dew-proof pipe configured so that the vicinity of a door contact surface including a partition portion of a housing adjacent to the freezer compartment is a low temperature side and the compressor is a high temperature side, and a vicinity of the door contact surface. A humidity sensor for detecting dew condensation or dew, a heating means provided on the dew-proof pipe in the vicinity of the compressor, and a control means for operating the heating means when dew or dew is detected by the humidity sensor. A refrigerator characterized by having. 10. The heat exchange point between the compressor and the heating means in the dew-proof pipe is set at a position higher than the bottommost portion of the dew-proof pipe. refrigerator.