JP2017161099A - refrigerator - Google Patents

Abstract

A refrigerator having a simple configuration, capable of efficiently performing a defrosting operation for removing frost formation of an evaporator, and reducing power consumption. A first temperature H1 which is an upper temperature of an evaporator 5 measured by a first temperature measuring unit 62 before starting a defrosting operation, and a lower part of the evaporator 5 measured by a second temperature measuring unit 62. When the difference value D1 from the second temperature H2 that is the temperature of the second is greater than the first first threshold Th1, the defrosting operation is terminated based on the measured temperature of the second temperature measurement unit 62, and the difference value D1 is the first difference value D1. When it is equal to or less than the first threshold Th1, the defrosting operation is terminated based on the measured temperature of the first temperature measuring unit 61. [Selection] Figure 3

Description

  The present invention relates to a refrigerator, and further to a defrosting operation for removing frost attached to an evaporator.

  A conventional refrigerator is disclosed in Patent Document 1. This refrigerator includes a glass tube heater (indirect heating means) arranged at the lower part of the evaporator and a pipe heater (direct heating means) arranged in contact with the evaporator for defrosting the evaporator. ing. Sensors (detection means) for detecting the temperatures of the top, bottom, left, right, and center of the evaporator are attached, and on / off and output control of the glass tube heater and pipe heater is performed based on the detection signal from the sensor. Is going.

  Since the glass tube heater and the pipe heater are controlled based on detection signals from temperature sensors arranged at a plurality of locations in the evaporator, it is possible to make the temperature of the evaporator uniform.

JP 2000-121233 A

  However, in the case of the refrigerator described in Patent Document 1, a plurality of sensors and a plurality of heating means are used, and the number of components increases. Further, since the plurality of heating means are controlled based on the detection signals from the plurality of sensors, the control is complicated and the capability required of the control circuit is increased. This causes an increase in the cost of the refrigerator.

  Then, an object of this invention is to provide the refrigerator which has a simple structure, performs efficiently the defrost operation which removes the frost formation of an evaporator, and can reduce power consumption.

  In order to achieve the above object, the present invention provides a refrigerator that cools a storage chamber with air cooled by circulating in an evaporator, and measures the temperature downstream of the evaporator in the air circulation direction. 1 temperature measurement part, 2nd temperature measurement part which measures the temperature of the upstream of the air circulation direction of the evaporator, a heating device which heats the evaporator, the 1st temperature measurement part, and the 2nd temperature measurement A control unit that acquires the measured temperature from the unit and controls the heating device, and the control unit performs a defrosting operation that operates the heating device to melt the frost of the evaporator, and The first temperature measured by the first temperature measuring unit and the second temperature measured by the second temperature measuring unit before the start of the defrosting operation are acquired, and the difference between the first temperature and the second temperature. When the difference value is larger than the first threshold value, it is based on the measured temperature of the second temperature measuring unit. There defrosting operation and exit, the difference value when the first threshold value or lower and terminates the defrosting operation on the basis of the measured temperature of the first temperature measuring unit.

  In an evaporator, when the amount of frost formation is small, air tends to flow through the evaporator. Therefore, since heat exchange is performed reliably, a temperature difference occurs between the downstream side (upper part) in the air circulation direction and the upstream side (lower part) in the air circulation direction. Therefore, the difference between the first temperature, which is the downstream (upper) temperature in the air flow direction, and the second temperature, which is the upstream (lower) temperature in the air flow direction, varies depending on the amount of frost formation. And the defrost operation according to the amount of frost formation is possible by determining the conditions of completion | finish of a defrost operation based on the difference in the amount of frost formation.

  Further, only the difference value between the first temperature and the second temperature is obtained, and the calculation process is simple. From these things, while having a simple structure, defrosting operation without excess and deficiency can be performed.

  The said structure WHEREIN: The return port which returns the air from the said storage chamber to the said upstream of the said evaporator is provided, and the said 2nd temperature measurement part becomes a downstream rather than the surface of the said evaporator facing the said return port. You may measure the temperature of the location. By doing in this way, it can control that the temperature of the air blown directly from the return port to the 2nd temperature measurement part is measured, and measurement accuracy falls. Moreover, since the heat of the heating apparatus arrange | positioned at the lower part of an evaporator is most supplied to the upstream of the lowest part, the heat of a heating apparatus is measured and it can suppress that a measurement precision falls. Furthermore, since the water melted on the downstream side (upper part) flows to the upstream side (lower part), it is possible to suppress the water from adhering and to suppress the measurement accuracy from being lowered due to the influence of the water.

  In the above-described configuration, the storage room includes a refrigeration room for storing articles at a low temperature, and a freezing room for storing articles at a lower temperature than the refrigeration room, and the control unit is disposed inside the evaporator. You may make it acquire the said 1st temperature and the said 2nd temperature during the period when the distribute | circulating air is cooling the said refrigerator compartment. When cooling a refrigerator compartment where the temperature for storing articles is high, the temperature of the returning air is high and the downstream (upper) and upstream (lower) of the air flow direction of the evaporator when the amount of frost formation is small The temperature difference tends to occur. Therefore, it is possible to accurately determine an appropriate defrosting condition for the current frosting state of the evaporator.

  In the above configuration, the return port includes a refrigerating chamber return port that returns air from the refrigerating chamber to the evaporator, and the second temperature measurement unit measures a temperature in the vicinity of the refrigerating chamber return port. May be.

  The said structure WHEREIN: The said control part may delay the start of a defrost operation, when the said difference value is larger than the 2nd threshold value larger than a 1st threshold value.

 ADVANTAGE OF THE INVENTION According to this invention, it can provide the refrigerator which has a simple structure, can perform the defrost operation which removes the frost formation of an evaporator efficiently, and can reduce power consumption.

It is a schematic front view of an example of the refrigerator concerning this invention. It is a cross-sectional view of the refrigerator shown in FIG. It is a block diagram of the refrigerator shown in FIG. It is a figure which shows schematic structure of an evaporator. It is a figure which shows the relationship between the temperature measured with the 1st temperature sensor at the time of defrost operation when there is little frost formation amount, and the temperature measured with the 2nd temperature sensor. It is a figure which shows the relationship between the temperature measured with the 1st temperature sensor at the time of defrost operation when there is much frost formation amount, and the temperature measured with the 2nd temperature sensor. It is a flowchart showing the defrost operation of the refrigerator concerning this invention. It is a flowchart showing the defrost operation of the refrigerator concerning this invention. It is a schematic front view of an evaporator. It is a flowchart which shows the other example of the defrost driving | operation of the refrigerator concerning this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic front view of an example of a refrigerator according to the present invention. FIG. 2 is a cross-sectional view of the refrigerator shown in FIG. FIG. 3 is a block diagram of the refrigerator shown in FIG. In the following description, the front-rear direction, the up-down direction, the left-right direction, and the like may be indicated. In this case, the state shown in FIG. Further, when describing the front side (front side) and the back side (rear side), the state shown in FIG. 2 is used as a reference, and in FIG. 2, the left side is the front side (front side) and the right side is the back side (rear side). Will be described. The arrows in FIGS. 1 and 2 indicate the flow of cold air.

  As shown in FIGS. 1 and 2, the refrigerator Rf has a heat insulating box 100 that is open on the front side and is surrounded by a wall filled with a foam heat insulating material. The heat insulation box 100 is provided with a partition shelf 101 that partitions the interior vertically. A machine room 102 is provided on the rear side of the lower part of the heat insulation box 100. The machine room 102 is separated by a space for storing articles of the heat insulating box 100 and a wall filled with foam heat insulating material. In the machine room 102, a part of a cooling device for cooling each storage room of the refrigerator Rf is arranged. In the refrigerator Rf, a compressor Comp and a control unit Cont (see FIG. 3) are arranged. In addition, devices other than these may be arranged.

  Like the other wall bodies, the partition shelf 101 is filled with a foam heat insulating material, and divides the space for storing articles of the heat insulating box body 100 in the vertical direction. Here, the lower side of the partition shelf 101 is the first space 1 and the upper side is the second space 2. In the refrigerator Rf, the first space 1 is provided with a storage room that is maintained at a temperature (for example, −18 ° C. or lower) at which the article can be reliably frozen. The second space 2 is provided with a storage room that is maintained at a temperature lower than the outside and a temperature at which the article is not easily frozen (for example, about 0 ° C. to about 8 ° C.).

  As shown in FIGS. 1 and 2, the first space 1 is provided with a lower freezing chamber 11, an upper freezing chamber 12, and an ice making chamber 13. The lower freezer compartment 11 and the upper freezer compartment 12 are storage compartments for storing stored items in a frozen state (for example, storing them at −18 ° C. or lower). The ice making chamber 13 is a storage chamber for producing and storing ice. In the refrigerator Rf, the lower freezer room 11, the upper freezer room 12, and the ice making room 13 are a single heat insulating area.

  As shown in FIG. 1, the lower freezer compartment 11 is provided in the lower part of the first space 1. The lower freezer compartment 11 includes a first storage case 111, a second storage case 112, a third storage case 113, and a door 114. The door 114 is a drawer door that opens and closes by moving back and forth. The first storage case 111 is a storage case having the largest capacity of the lower freezer compartment 11 and is arranged at the lowermost part of the lower freezer compartment 11. The first storage case 111 moves integrally with the door 114. The second storage case 112 is disposed above the first storage case 111, and the third storage case 113 is disposed above the second storage case 112.

  When the door 114 is opened, the second storage case 112 and the third storage case 113 are movable in the front-rear direction independently of the first storage case 111. In the lower freezer compartment 11, the second storage case 112 and the third storage case 113 move together with the first storage case 111 when the door 114 is opened and closed.

  The upper part of the lower freezing chamber 11 of the first space 1 is divided into left and right, and the divided right side is the upper freezing chamber 12 and the left side is the ice making chamber 13. The upper freezer compartment 12 includes a door 121 and a storage case 122. The door 122 is a drawer door that opens and closes by moving back and forth. The storage case 122 moves integrally with the door 121.

  The ice making chamber 13 includes a door 131, a storage case 132, and an ice making machine 133. The door 131 is a drawer door that opens and closes by moving back and forth. The storage case 132 moves integrally with the door 131. The ice making machine 133 is an apparatus for producing ice by freezing water supplied from a water tank (not shown). The ice making machine 133 is arranged above the storage case 132, and the manufactured ice falls into the storage case 132.

  As shown in FIG. 2, a partition wall 14 is provided on the back side of the first space 1. Between the partition wall 14 and the wall surface on the back side of the first space 1, a cold air flow path 3 through which cool air for cooling the lower freezer chamber 11, the upper freezer chamber 12, and the like is provided. As shown in FIG. 1, the first space 1 of the heat insulating box 100 is provided with a groove extending vertically in the center portion, and the partition wall 14 covers the front of the groove. A gap between the partition wall 14 and the groove is the cold air passage 3.

  The cold air passage 3 is partitioned forward and backward by a partition member 30. The rear side of the partition member 30 is a cold air generating part 31, and the front side is a cold air duct 32. The cool air generating unit 31 is provided with an evaporator 5 that is a cooler of the refrigerator Rf and a freezing fan 33. The evaporator 5 cools the surrounding air by removing heat from the surrounding air when the refrigerant evaporates inside. Details of the evaporator 5 will be described later. The refrigeration fan 33 is a blower that generates an air flow (air flow) in the cold air passage 3. The refrigeration fan 33 is disposed above the evaporator 5. By operating the refrigeration fan 33, a rising air flow is generated in the cold air generation unit 31. That is, the airflow passes through the evaporator 5 by operating the refrigeration fan 33. In the refrigerator Rf, the refrigeration fan 33 operates when the cooling device is performing a cooling operation.

  The cold air generating unit 31 is connected to the cold air duct 32 at the upper part. The cold air generated in the cold air generating unit 31 flows into the cold air duct 32. The cold air duct 32 is an air passage for supplying cold air to the lower freezer compartment 11 and the upper freezer compartment 12. The cold air duct 32 is provided with discharge ports 321, 322, 323, and 324 that are through holes formed in the partition wall 14. The discharge ports 321, 322, and 323 are respectively provided at positions where cool air flows into the first storage case 111, the second storage case 112, and the third storage case 113 of the lower freezer compartment 21. Further, the discharge port 324 is provided at a position where the discharge port 324 flows into the upper freezer compartment 12. In the refrigerator Rf, cold air is allowed to flow into the ice making chamber 13 from the upper freezer compartment 12, but a discharge port that allows cold air to flow into the ice making chamber 13 may be provided.

  The cold air that has flowed into the lower freezer compartment 11 and the upper freezer compartment 12 and has cooled the interior of the first space 1 returns to the cold air generator 31 via the freezing return duct 34. The refrigeration return duct 34 is provided below the first storage case 111 and is connected to the cold air generating unit 31 below the evaporator 5. That is, the cold air that has cooled the lower freezer room 11, the upper freezer room 12, and the ice making room 13 passes through the return duct 34 and returns to the cold air generator 31. The cool air returning to the return duct 34 may be referred to as refrigerated return cool air.

  As shown in FIGS. 1 and 2, the second space 2 includes a refrigerator room 21, a chilled room 22, and a vegetable room 23 from the top. In addition, the refrigerator compartment 21 is maintained at the low temperature (for example, 3 to 5 degreeC) which can suppress deterioration of articles | goods. Further, the chilled chamber 22 is maintained at a temperature (for example, 0 ° C. to 1 ° C.) that is lower than the refrigerated chamber 21 and that prevents the articles from freezing. The vegetable room 23 is maintained at a temperature (for example, 7 ° C. to 8 ° C.) that suppresses a decrease in freshness of the vegetable. In addition, these storage rooms and its maintenance temperature are examples, and the range of the temperature at which articles | goods cannot freeze easily may be sufficient, and you may provide the storage room of temperature different from these.

  The front side of the second space 2 is open, and a refrigeration door 27 is provided on the front side so as to be opened and closed. The refrigeration door 27 is pivotally supported by the heat insulation box 100 and opens and closes the opening of the second space 2 by rotating around the support shaft. The refrigeration door 27 may be capable of closing the opening of the second space 2 with one member (door), or may be capable of being closed with two or more members (doors). Good. Here, it is the refrigeration door 27 that can block the opening of the second space 2 with one sheet.

  In the refrigerator Rf, by opening the refrigeration door 27, articles can be stored in the refrigerated room 21, the chilled room 22, and the vegetable room 23, or stored articles can be taken out. Inside the refrigerated door 27 is provided a door pocket 271 for storing articles such as bottles, cans, paper packs and the like to be stored upright.

  The refrigerator compartment 21 is provided with a movable shelf 24 that can partition the space up and down. As shown in FIGS. 1 and 2, three movable shelves 24 are provided. The movable shelf 24 is used as a shelf by engaging with a convex portion (not shown) protruding from the inner wall of the refrigerator compartment 21. And the movable shelf 24 can change the position of the height direction in the refrigerator compartment 21. By changing the position of the movable shelf 24, various kinds of articles having different shapes (for example, size and height) can be stored. A fixed shelf 25 fixed to the inner wall of the heat insulating box 100 is attached to the lowermost stage of the refrigerator compartment 21.

  And the fixed shelf 26 fixed to the inner wall of the heat insulation box 100 is attached below the fixed shelf 25 with a fixed space | interval. The portion sandwiched between the fixed shelf 25 and the fixed shelf 26 is the tilt chamber 22, and the portion sandwiched between the fixed shelf 26 and the partition shelf 101 is the vegetable chamber 23. The chilled chamber 22 includes a storage case 221. The storage case 221 is provided to be slidable back and forth. A front door 222 that opens and closes the front surface of the chilled chamber 22 is provided on the front surface of the storage case 221. Note that packing is provided on at least one of the inner surface of the front door portion 222 or the chilled chamber 22. By storing the storage case 221 in the back, the front door portion 222 closes the opening on the front surface of the chilled chamber 22. Further, the chilled chamber 22 is restricted in air flow and has a temperature different from that of the refrigerated chamber 21.

  The vegetable room 23 has the same configuration as the chilled room 22 and includes a storage case 231 and a front door portion 232. Unlike the chilled chamber 22, the vegetable chamber 23 is formed with a gap that allows air to flow in. Thereby, the cool air which cooled the refrigerator compartment 21 and the chilled chamber 22 mentioned later can be made to flow into the vegetable compartment 23. FIG. A return opening 441 of a refrigeration return duct 44 described later is provided on the back side of the vegetable compartment 23. The cold air flowing in from the return opening 441 flows into the refrigeration return duct 44.

  As shown in FIG. 2, a partition wall 28 is provided in the back of the second space 2. Between the partition wall 28 and the wall surface on the back side of the second space 2, a cold air flow path 4 through which cold air for cooling the refrigerator room 21, the chilled room 22 and the vegetable room 23 flows is provided. As shown in FIG. 1, the second space 2 of the heat insulating box 100 is provided with a vertically extending groove at the center, and the partition wall 28 covers the front of the groove. A gap between the partition wall 28 and the groove becomes the cool air flow path 4.

  The cold air flow path 4 includes a damper 41, a refrigeration fan 42, a discharge port 43, and a refrigeration return duct 44. The damper 41 adjusts the inflow of cold air from the cold air passage 3 by opening and closing the through holes 103 provided in the partition shelf 101 as necessary. The refrigeration fan 42 is a blower for pushing away the cool air that flows in by opening the damper 41. By the operation of the refrigeration fan 42, the cold air rises in the cold air flow path 4. The discharge port 43 is a through hole provided in the partition wall 28. In the refrigerator Rf, five discharge ports 43 are provided, but the present invention is not limited to this, and may be more or less. It suffices to be provided at least at a position where cold air flows into the refrigerated chamber 21 and the chilled chamber 22.

  The cold air flowing through the cold air flow path 4 flows into the refrigerator compartment 21 and the chilled chamber 22 through the discharge port 43. The vegetable room 23 has a higher storage temperature than the refrigerated room 21 and the chilled room 22. For this reason, the vegetable compartment 23 is cooled by flowing cold air that has been heated from the articles in the refrigerator compartment 21 or the chilled compartment 22 into the vegetable compartment 23. The cold air that has cooled the vegetable compartment 23 passes through the refrigeration return duct 44 and is returned to the cold air generating unit 31 in which the evaporator 5 is provided. The cold air that has cooled the vegetable room 23 and has flowed into the refrigeration return duct 44 may be referred to as refrigeration return cold air.

  The refrigeration return duct 44 extends downward from the back side of the vegetable compartment 23 to the back side of the first space 1. The refrigerated return duct 44 includes a return opening 441 and a return port 442. Similar to the cold air flow path 4, the refrigeration return duct 44 is formed in a space sandwiched between the groove and the partition wall 28. The return opening 441 is a through hole that penetrates the partition wall 28. The refrigerated return air flowing from the return opening 441 flows downward in the refrigeration return duct 44. And as shown in FIG. 1, it returns to the cold air generation | occurrence | production part 31 of the cold air path 3 from the lower right side of the evaporator 5. As shown in FIG.

  In the cooling device for the refrigerator Rf according to the present invention, the single evaporator 5 cools all the storage rooms. The cold air passage 3 and the cold air passage 4 are communicated with each other through the through hole 103 of the partition shelf 101, and the amount of the cold air generated in the cold air passage 3 is adjusted by opening and closing the damper 41. Has been. That is, when the cooling device is operating with the damper 41 closed, the cool air generated by the cool air generating unit 31 circulates in the first space 1. Further, when the cooling device is operating with the damper 41 opened, the cold air circulates in both the first space 1 and the second space 2. That is, the damper 41 is opened only when the refrigerator compartment 21, the chilled compartment 22, and the vegetable compartment 23 are cooled.

  A cooling device for the refrigerator Rf will be described. The cooling device uses a refrigeration cycle. The refrigeration apparatus has a configuration in which a compressor Comp, a condenser (not shown), an expander (not shown), and an evaporator 5 are connected by a pipe (not shown), and the inside is filled with a refrigerant. Yes. In the refrigeration apparatus, the refrigerant is compressed by a compressor and condensed by a condenser. The condensed refrigerant is expanded by the expander and then evaporated by the evaporator 5. And cool air is produced | generated by taking away the heat of vaporization by evaporation of a refrigerant | coolant from air. In addition, about a cooling device, since the well-known technique is utilized, the detail is abbreviate | omitted.

  Next, the evaporator 5 will be described with reference to the drawings. FIG. 4 is a diagram showing a schematic configuration of the evaporator. As shown in FIG. 4, the evaporator 5 includes a pipe 51 and fins 52. As shown in FIG. 4, the pipe 51 includes an inflow portion and an outflow portion into which the refrigerant flows in an upper portion. The pipe 51 meanders left and right toward the lower part, is folded back in the direction intersecting the meandering direction (the depth direction in FIG. 4) at the lower end, and again meanders right and left toward the upper part.

  The fin 52 is a flat plate. A plurality of fins 52 are provided and are arranged in parallel in the horizontal direction. The pipe 51 passes through the fins 52, and the pipe 51 and the fins 52 are connected. The pipe 51 and the fin 52 are made of a material having a high thermal conductivity (for example, a metal material such as aluminum or copper). The air flowing between the fins 52 is heat-exchanged with the refrigerant flowing inside the pipe 51 to become cold air.

  As described above, the cool air generated in the evaporator 5 returns to the cool air generating unit 31 provided with the evaporator 5 from below the evaporator 5 after cooling each storage chamber of the refrigerator Rf. When the returned cold air is referred to as return cold air, the return cold air cools the inside by receiving heat from the articles and air inside the storage chambers of the refrigerator Rf. Therefore, the temperature of the return cold air is higher than that when it is generated in the cold air generation unit 31. And when return cold air passes the inside of the evaporator 5 upwards, it is cooled again and is sent to each store room as cold air.

  For example, when the door is opened for a long time or when an article having a high temperature or easily evaporating water is stored, the humidity of the return cold air increases. And when return cold air with high humidity is cooled when circulating in the evaporator 5, the moisture contained in the return cold air adheres as frost on the surface of the evaporator 5. The fins 52 are clogged by the adhesion of frost, and it becomes difficult for the air to flow between the fins 52, and the cooling efficiency is lowered. Therefore, in the refrigerator Rf, a defrosting operation is performed in which the evaporator 5 is heated to melt the frost.

  Next, the configuration necessary for the defrosting operation will be described. In order to perform the defrosting operation, a first temperature sensor 61 (first temperature measuring unit) that measures the temperature of the evaporator 5, a second temperature sensor 62 (second temperature measuring unit), and an evaporator during the defrosting operation. And a glass tube heater 7 (heating device) for heating 5. The first temperature sensor 61 is provided on the top of the evaporator 5. The second temperature sensor 62 is provided below the evaporator 5. Note that the evaporator 5 is configured such that it returns from below and cool air flows in and then passes upward through the evaporator 5.

  If cold air is blown directly to the second temperature sensor 62, it is difficult to detect the exact temperature of the evaporator 5. Therefore, it is preferable that the second temperature sensor 62 measures the temperature at a position shifted from the lower end portion (upstream end in the air flow direction) of the evaporator 5 to the upper portion (downstream direction). In the case of the lower end portion, water that has melted back cold air or frost also flows down, so that it is easily affected by these effects. Also from these things, it is better that it is not a lower end part.

  The glass tube heater 7 is disposed below the evaporator 5. The glass tube heater 7 heats the surrounding air and the evaporator 5 with radiant heat by passing an electric current. When the frost adhering to the evaporator 5 is melted by the defrosting operation, water falls downward. If the water adheres directly to the glass tube heater 7, it may cause a failure or breakage. Therefore, a heater cover for avoiding water is provided above the glass tube heater 7. In addition, a defrost water receiver 53 for receiving water generated during the defrosting operation is provided below the glass tube heater 7. The defrost water is collected by the defrost water receiver 53 and then flows into an evaporating dish (not shown).

  Further, when the second temperature sensor 62 is provided at the lower end, the heat of the glass tube heater 7 may be directly detected, and in this case also, it is difficult to accurately measure the temperature of the evaporator 5. . From this point of view, it is preferable that the second temperature sensor 62 measures the temperature at a position shifted upward from the lower end of the evaporator 5.

  Next, the electrical configuration of the refrigerator Rf will be described. As shown in FIG. 3, in the refrigerator Rf according to the present invention, the damper 41, the refrigeration fan 42, the refrigeration fan 33, the first temperature sensor 61, the second temperature sensor 62, the glass tube heater 7, and the compressor Comp are controlled by the controller Cont. It is connected to the. In addition, a storage unit Mem and a timer unit CL are connected to Cont. The control unit Cont can always access the storage unit Mem, can store information in the storage unit Mem, and can read information from the storage unit Mem. The memory | storage part Mem has the structure containing semiconductor memories, such as ROM and RAM. In addition to these, a portable memory such as a flash memory or a hard disk may be used. Further, the control may be performed by storing a control program in the storage unit Mem and starting a necessary control program as necessary.

  The timer unit CL is a circuit that measures time. The timer unit CL can measure the current time, the elapsed time from a predetermined time point, and the like. The control unit Cont can access the time measuring unit CL and can acquire the measured time information.

  The control part Cont controls each part to perform the defrosting operation. In the defrosting operation, the evaporator 5 is heated to a temperature higher than the temperature at which the ice melts, and the frost adhering to the evaporator 5 is melted. Therefore, the controller Cont stops the compressor Comp during the defrosting operation, and suppresses the evaporation of the refrigerant in the evaporator 5. Further, during the defrosting operation, the air around the evaporator 5 is also warmed. Therefore, the control unit Cont stops the refrigeration fan 42 and the freezing fan 33 and closes the damper 41. Thereby, inflow of the warmed air into each storage room is restricted, and the temperature rise of each storage room is suppressed.

  In the refrigerator Rf, a defrosting operation is performed at regular intervals in order to ensure a stable cooling capacity for a long period of time. Further, if the fins 52 are clogged due to frost formation, the heat exchange efficiency of the evaporator 5 is lowered, so that the cooling of each storage chamber is deteriorated, that is, the temperature is hardly lowered. Even when the refrigeration apparatus is driven (the compressor Comp is driven), the defrosting operation may be performed when the temperature of the storage room does not decrease. In the following description, control part Cont demonstrates as what performs a defrost operation regularly.

  The defrosting operation will be described in detail. A temperature difference between the first temperature sensor and the second temperature sensor of the evaporator 5 during the defrosting operation when the amount of frost formation is different will be described with reference to the drawings. FIG. 5 is a diagram showing the relationship between the temperature measured by the first temperature sensor and the temperature measured by the second temperature sensor during the defrosting operation when the amount of frost formation is small. FIG. 6 is a diagram illustrating a relationship between the temperature measured by the first temperature sensor and the temperature measured by the second temperature sensor during the defrosting operation when the amount of frost formation is large.

  5 and 6, the horizontal axis represents time and the vertical axis represents temperature (° C.). The temperature measured by the first temperature sensor 61 is indicated by a broken line, and the temperature measured by the second temperature sensor 62 is indicated by a solid line. Moreover, the temperature of the lower freezer compartment 11 and the temperature of the refrigerator compartment 21 are also shown. And when time is 0, the defrost operation is started and the temperature change from 10 minutes before the defrost operation start is shown. It is assumed that the part before the time 0 is that the cooling device performs a normal cooling operation.

  As shown in FIG. 5, when the amount of frost formation on the evaporator 5 is small, the measured temperature h <b> 1 of the first temperature sensor 61 during the cooling operation is lower than the measured temperature h <b> 2 of the second temperature sensor 62. This is due to the following. In the refrigerator Rf, the refrigerated return air and the refrigerated return air flow into the lower part of the evaporator 5 through the refrigeration return duct 34 and the refrigeration return duct 44. The refrigeration return cold air and the refrigeration return cold air are heated in each storage room. The refrigeration return cold air and the refrigeration return cold air are cooled when rising between the fins 52 of the evaporator 5. At this time, since the evaporator 5 is heated by taking heat from the cold air, the lower part that obtains more heat becomes higher than the upper part.

  In the graph shown in FIG. 5, the temperature difference between the measurement temperature h1 and the measurement temperature h2 is 2 ° C. to 3 ° C. Then, when the glass tube heater 7 is driven and the defrosting operation is turned on, the measurement temperature h1 and the measurement temperature h2 rise to substantially the same temperature. At approximately the same timing, the measurement temperature h1 and the measurement temperature h2 reach 0 ° C. The measured temperature h2 has a slightly gentler gradient, and then the temperature rapidly increases again. In addition, the measurement temperature h1 is maintained at 0 ° C. for a certain time, and the temperature starts to rise rapidly after the measurement temperature h2.

  The measured temperature h1 has a longer stagnation time around 0 ° C. because the glass tube heater 7 is higher in the upper part of the evaporator 5 (around the first temperature sensor 61) than in the lower part (around the second temperature sensor 62). This is because the distance is far from.

  On the other hand, as shown in FIG. 6, when the amount of frost formation on the evaporator 5 is large, the measured temperature h1 of the first temperature sensor 61 and the measured temperature h2 of the second temperature sensor 62 during the cooling operation are not so different. This is due to the following. If frost adheres to the evaporator 5 and the gap between the fins 52 is filled, the refrigeration return cold air and / or the refrigeration return cold air cannot pass between the fins 52. Therefore, the heat exchange between the air and the refrigerant is not sufficiently performed in the evaporator 5. Thereby, the evaporator 5 hardly receives heat from cold air, and the temperature difference between the upper part and the lower part of the evaporator 5 becomes small.

  Then, when the glass tube heater 7 is driven and the defrosting operation is turned on, the measurement temperature h1 and the measurement temperature h2 rise to substantially the same temperature. At approximately the same timing, the measurement temperature h1 and the measurement temperature h2 reach 0 ° C. The measurement temperature h2 is maintained at 0 ° C. for a short time, and the gradient is slightly lowered in other places, and then the temperature rises rapidly again. In addition, the measurement temperature h1 is maintained at 0 ° C. for a longer time than when the amount of frost formation is small, and the temperature starts to rise rapidly after the measurement temperature h2.

  The measured temperature h2 is maintained at a constant temperature after the temperature has rapidly increased. This is because the amount of heat supplied from the glass tube heater 7 to the evaporator 5 and the latent heat used for defrosting above the evaporator 5 are balanced. That is, it is difficult to confirm whether a sufficient amount of heat is supplied to remove the frost in the evaporator 5 because the measured temperature h2 of the second temperature sensor 62 has risen to a certain temperature. Therefore, when the amount of frost formation is large, the glass tube heater 7 is continuously driven until the measured temperature h1 of the first temperature sensor 61, which is far from the glass tube heater 7 and hardly transfers heat, becomes 10 ° C.

  From the above, when the frosting amount of the evaporator 5 is different in the cooling operation of the cooling device, the temperature difference between the upper part and the lower part is different. In the defrosting operation of the refrigerator Rf according to the present invention, the frosting state (frosting amount) of the evaporator 5 is determined based on the temperature difference between the upper part and the lower part of the evaporator 5 and is removed based on the frosting state. Frost operation is performed. Below, the detail of the defrost operation of refrigerator Rf concerning this invention is demonstrated with reference to drawings. FIG. 7 is a flowchart showing the defrosting operation of the refrigerator according to the present invention.

  The control unit Cont measures the temperature of the first temperature sensor 61 and the second temperature sensor 62 at a predetermined interval (for example, once every several tens of seconds) while the cooling device performs the cooling operation. The measurement result is stored in the storage unit Mem. And in refrigerator Rf, defrosting operation is performed for every fixed time (for example, 24 hours). That is, the defrosting start time is determined in advance, and the control unit Cont confirms that the defrosting operation start time is reached based on the time information from the time measuring unit CL, and then operates the glass tube heater 7. Start (step S101).

  The control part Cont starts with the defrosting operation, and from the storage part Mem, the first temperature H1 measured by the first temperature sensor 61 before the defrosting start time and a second temperature measured by the second temperature sensor 62. The temperature H2 is received (step S102). Here, the first temperature H1 and the second temperature H2 are measured values a predetermined time before the defrosting start time, but are not limited thereto. For example, it may be the sum or average of 10 measurement results from a predetermined time T0. Note that the temperature measurement by the first temperature sensor 61 and the second temperature sensor 62 is continued even after the start of the defrosting operation. Further, the predetermined time T0 may be “0”. When the predetermined time T0 is “0”, the first temperature H1 and the second temperature H2 are temperatures measured by the first temperature sensor 61 and the second temperature sensor 62 immediately before the start of the defrosting operation.

  The controller Cont calculates a difference value D1 (= | H2−H1 |) between the first temperature H1 and the second temperature H2 (step S103). In the evaporator 5 when the cooling device is normally operated, as described above, the second temperature H2 that is the lower temperature is higher than the first temperature H1 that is the upper temperature. However, since there is a possibility of reverse rotation, here, it is expressed as a difference and displayed as an absolute value obtained by subtracting the first temperature H1 from the second temperature H2.

  As described above, the temperature difference between the upper part and the lower part of the evaporator 5 is related to the frost formation amount of the evaporator 5. Therefore, in order to determine the frost formation amount of the evaporator 5, the control unit Cont compares the difference value D1 calculated in step S103 with the first threshold value Th1 (step S104). When the difference value D1 is larger than the first threshold value Th1 (Yes in step S104), since the temperature difference between the upper part and the lower part of the evaporator 5 is large, the controller Cont has a small amount of frost formation on the evaporator 5. The control unit Cont confirms whether or not the measured temperature h2 of the second temperature sensor 62 measuring the temperature of the lower part of the evaporator 5 has exceeded a predetermined temperature a1 (step S105). When the amount of frost formation is small, the temperature difference (about 3 ° C. to 4 ° C.) shown in FIG. 5 is generated, and therefore the first threshold Th1 can be smaller than this value (for example, 2 ° C.). . Since FIG. 5 is an example, the first threshold Th1 is also an example and is not limited to this.

  The controller Cont continues to heat the evaporator 5 with the glass tube heater 7 until the measured temperature h2 of the second temperature sensor 62 exceeds the predetermined temperature a1 (until Yes in step S105). When the measured temperature h2 of the second temperature sensor 62 exceeds the predetermined temperature a1 (Yes in Step S105), the control unit Cont stops the glass tube heater 7 and ends the defrosting operation (Step S106). . Usually, immediately after the defrosting operation is stopped, the temperatures of the lower freezer room 11, the upper freezer room 12, the ice making room 13, the refrigerated room 21, the chilled room 22, and the vegetable room 23 are rising. The control part Cont restarts the cooling of the necessary storage rooms according to the temperature of each storage room.

  Further, when the difference value D1 is equal to or less than the first threshold Th1 (No in step S104), since the temperature difference between the upper part and the lower part of the evaporator 5 is small, the controller Cont has a large amount of frost formation in the evaporator 5. Judge.

  Defrosting is an operation in which frost attached to the evaporator 5 is melted to form water and removed from the evaporator 5. And latent heat is required when melting frost into water. When the amount of frost formation is large, a large latent heat is required, and it is often difficult to supply sufficient latent heat to the frost with only the residual heat after heating the evaporator 5. Further, as shown in FIG. 6, when the heat supplied from the glass tube heater 7 and the latent heat when melting the frost are antagonized, even if the heat is supplied from the glass tube heater 7, the lower temperature (the first temperature) In some cases, the measured temperature h2) of the two-temperature sensor 61 does not change. Therefore, when the amount of frost formation is large, the operation of the glass tube heater 7 is controlled based on the measured temperature 1 of the first temperature sensor 61 that measures the temperature on the upper side of the evaporator 5.

  That is, the control unit Cont confirms whether or not the measured temperature h1 of the first temperature sensor 61 that measures the temperature of the upper part of the evaporator 5 that becomes a low temperature during normal operation exceeds a predetermined temperature a2 (step S1). S107). The controller Cont continues heating the evaporator 5 with the glass tube heater 7 until the measured temperature h1 of the first temperature sensor 61 exceeds the predetermined temperature a2 (until Yes in step S107). When the measured temperature h1 of the first temperature sensor 61 exceeds the predetermined temperature a2 (Yes in step S107), the control unit Cont stops the glass tube heater 7 and ends the defrosting operation (step S106). .

  As described above, in the refrigerator Rf according to the present invention, the first temperature H1 that is the upper temperature of the evaporator 5 and the second temperature H2 that is the lower temperature before the defrosting start time. Based on the difference, the amount of frost formation is determined. If the amount of frost formation is small according to the amount of frost formation, the defrosting operation is terminated based on the measured temperature h2 of the second temperature sensor 62, which is the temperature below the evaporator 5, and the amount of frost formation. When there are many, control which complete | finishes a defrost operation based on the measured temperature h1 of the 1st temperature sensor 61 which is the temperature of the lower part of the evaporator 5 is performed. Thereby, when there is much frost formation amount, the drive time of the glass tube heater 7 can be lengthened and reliable defrost operation can be performed. Further, when the amount of frost formation is small, the driving time of the glass tube heater 7 can be shortened to reduce the power consumption, and the temperature rise of each storage room during the defrosting operation can be suppressed.

  Although it is assumed that the first temperature sensor 61 and the second temperature sensor 62 always measure the temperature at regular intervals, the present invention is not limited to this. The control part Cont recognizes in advance the timing of the next defrosting start, and may start the measurement at a certain time before the timing of the defrosting start. This certain time is a time before the predetermined time described above. For example, if the defrosting operation is performed once every 24 hours, the measurement is performed at regular intervals (for example, 30 seconds) with the first temperature sensor 61 and the second temperature sensor 62 after 23 hours have passed since the previous defrosting operation. The temperatures h1 and h2 are measured. If the time To is 30 minutes, the measured temperatures of the first temperature sensor 61 and the second temperature sensor 62 after 30 minutes from the start of measurement may be set as the first temperature H1 and the second temperature H2.

  Moreover, about 1st threshold value Th1, predetermined temperature a1, predetermined temperature a2, when refrigerator Rf is drive | operated on several conditions and the frost formation state to the evaporator 5 in each condition and defrost operation were performed This value is determined by observing the defrosting state. The predetermined temperature a1 and the predetermined temperature a2 may be different temperatures or the same temperature.

(Second Embodiment)
Another example of the refrigerator according to the present invention will be described with reference to the drawings. In the present embodiment, only the measurement timing of the first temperature H1 and the second temperature H2 at the start of the defrosting operation is different. Therefore, in the following description, reference is made to the refrigerator Rf described in the first embodiment.

  In the lower part of the evaporator 5, the refrigerated return cold air that passes through the lower freezer compartment 11, the upper freezer compartment 12, and the ice making chamber 13, and the refrigerated return cold air that passes through the refrigerator compartment 21, the chilled compartment 22 and the vegetable compartment 23 And inflow. Therefore, the temperature of the refrigeration return cold air is lower than that of the refrigeration return cold air, and the temperature difference between the cold air generated from the evaporator 5 and the refrigeration return cold air is larger than the temperature difference between the cold air generated from the evaporator 5 and the refrigeration return cold air. small. And the temperature difference of the upper part and lower part when the amount of frost formation of the evaporator 5 is small becomes large, so that the temperature of return cold air is high.

  The refrigerator Rf is configured such that when the damper 41 is open, the refrigerated return cold air returns to the evaporator 5 together with the refrigeration return cold air. Therefore, when the amount of frost formation on the evaporator 5 is small, the temperature difference between the upper part and the lower part of the evaporator 5 is larger when the damper 41 is open than when the damper 41 is closed. When the amount of frost formation on the evaporator 5 is large, the return cold air hardly flows to the evaporator 5, so that a temperature difference between the upper part and the lower part hardly occurs regardless of whether the damper 41 is opened or closed. Therefore, the refrigerator Rf according to the present embodiment uses the characteristic that the temperature difference between the upper part and the lower part of the evaporator 5 increases when the damper 41 is open. That is, the frost formation amount of the evaporator 5 is determined based on the temperature difference between the upper part and the lower part of the evaporator 5 when the previous (most recent) damper 41 is opened. Thereby, compared with the case where the temperature difference of the upper part of the evaporator 5 and the lower part when the damper 41 is closed is utilized, the precision of determination of the amount of frost formation of the evaporator 5 can be improved.

  In the refrigerator Rf according to the present embodiment, the controller Cont opens the damper 41 and drives the refrigeration fan 42 when the temperature of the refrigeration chamber 21 exceeds a certain temperature (for example, 5 ° C.). Let cool air flow into 4. Thereby, the refrigerator compartment 21, the chilled room 22, and the vegetable compartment 23 are cooled. Here, the damper 41 is opened based on the temperature of the refrigerating chamber 21, but the present invention is not limited to this. For example, the damper 41 may be controlled to open based on the temperature of the chilled chamber 22 separately or in addition to this. Moreover, you may make it open the damper 41 based on the temperature of the vegetable compartment 23. FIG.

  When the damper 41 is opened, refrigerated return cold air flows into the evaporator 5. Therefore, the temperature difference of the evaporator 5 becomes large between the upper part and the lower part. Therefore, after a certain time has elapsed since the damper 41 was opened, the controller Cont sets the measured temperature h1 of the first temperature sensor 61 and the measured temperature h2 of the second temperature sensor 62 to the first temperature H11 and the second temperature, respectively. The temperature H21 is stored in the storage unit Mem. Immediately after the damper 41 is opened, the cool air is not circulated, and the air in the refrigerating chamber 21 flows into the evaporator 5 via the refrigerating return duct 44, so In many cases, the second temperature H21 is not an accurate value.

  By measuring the first temperature H11 and the second temperature H21 after a certain period of time and when the circulation of cold air is stabilized, the influence of frost appears on the first temperature H11 and the second temperature H21. It becomes easy. The first temperature H11 and the second temperature H21 may be the temperature of one measurement, or may be the sum of the measurement results of a plurality of times. Further, it may be an average of a plurality of measurement results.

  In the refrigerator Rf, as described above, the first temperature H11 and the second temperature H21 when the damper 41 is in the open state are stored in the storage unit Mem. The defrosting operation of the refrigerator Rf will be described with reference to the drawings. FIG. 8 is a flowchart showing the defrosting operation of the refrigerator according to the present invention. The flowchart shown in FIG. 8 is obtained by replacing steps S102 to S104 in the flowchart shown in FIG. 7 with steps S202 to S205. Therefore, in the following description, a different part from the flowchart of FIG. 7 is mainly demonstrated.

  The control part Cont starts the operation of the glass tube heater 7 when it is confirmed that it is the start time of the defrosting operation based on the time information from the time measuring part CL (step S101). The controller Cont checks whether or not the time from the previous opening of the damper 41 to the current time is longer than the time T1 (step S202). When the time from the previous opening of the damper 41 to the current time is longer than the time T1 (No in step S202), the control unit Cont acquires the first temperature H1 and the second temperature H2 (step in FIG. 7). S102). Then, control is performed along the flow of the flowchart shown in FIG.

  When the time from the previous opening of the damper 41 to the current time is shorter than the time T1 (Yes in step S202), the controller Cont performs the first temperature H11 and the second temperature H21 when the previous damper 41 is opened. Is acquired (step S203).

  The controller Cont calculates a difference value D2 = (| H21−H11 |) between the first temperature H11 and the second temperature H21 (step S204). The calculation method is the same as in the first embodiment. The controller Cont compares the difference value D2 calculated in step S204 with the second threshold Th2 (step S205). When the difference value D2 is larger than the second threshold value Th2 (Yes in step S205), since the temperature difference between the upper part and the lower part of the evaporator 5 is large, the controller Cont has a small amount of frost formation in the evaporator 5. It is judged that. The second threshold Th2 may be the same value as the first threshold Th1, but the temperature difference between the upper part and the lower part of the evaporator 5 when the damper 41 is opened is larger than when the damper 41 is closed. Therefore, the second threshold value Th2 may be larger than the first threshold value Th1.

  When the amount of frost formation on the evaporator 5 is small, the controller Cont determines whether or not the measured temperature h2 of the second temperature sensor 62 that measures the temperature of the lower part of the evaporator 5 exceeds a predetermined temperature a1. (Step S105). Thereafter, the defrosting operation is completed with the same operation as the flowchart shown in FIG.

  If the difference value D2 is equal to or smaller than the second threshold Th2 (No in step S205), the controller Cont has a large amount of frost formation on the evaporator 5 because the temperature difference between the upper part and the lower part of the evaporator 5 is small. Judge.

  When the amount of frost formation is large, the controller Cont determines whether or not the measured temperature h1 of the first temperature sensor 61 that measures the temperature of the upper part of the evaporator 5 that becomes low temperature during normal operation exceeds a predetermined temperature a2. (Step S107). Thereafter, the defrosting operation is completed with the same operation as the flowchart shown in FIG.

  Thus, by utilizing the temperature difference (the difference value D2 between the first temperature H11 and the second temperature H21) between the upper part and the lower part of the evaporator 5 when the previous damper 41 is opened at the start of the defrosting operation. When the damper 41 is closed, there may be a case where a large temperature difference can be acquired even when the temperature difference between the upper part and the lower part of the evaporator 5 is difficult to be attached. By doing in this way, the frost formation state of the evaporator 5 can be acquired more correctly, and it is possible to reduce the time required for defrosting.

  In the present embodiment, the difference value D2 between the first temperature H11 and the second temperature H21 when the damper 41 is opened is compared with the second threshold Th2, but the present invention is not limited to this. For example, a ratio between the difference value D2 when the damper 41 is opened and the difference value D1 when the damper 41 is closed may be calculated and the ratios may be compared.

(Modification)
In this embodiment, the temperature difference between the upper part and the lower part of the evaporator 5 when the damper 41 is opened is measured. Therefore, the second temperature sensor 62 may be provided in the vicinity of the return port 442 of the refrigeration return duct 44 as shown in FIG. FIG. 9 is a schematic front view of the evaporator. In the evaporator 5 shown in FIG. 9, in the refrigerator Rf, a return port 442 is provided at a position facing the lower right side of the evaporator 5. Therefore, a second temperature sensor 62b is provided on the right side of the lower portion of the evaporator 5. Although the 2nd temperature sensor 62b is the vicinity of the return port 442, it is installed in the position where refrigeration return cold air does not hit directly. Thereby, the temperature of the evaporator 5 is accurately measured. The second temperature sensor 62b measures the temperature in the vicinity of the portion to which the refrigerated return cold air having a high temperature is blown. Therefore, the difference value D2 between the first temperature H11 and the second temperature H21 can be increased. Thereby, the precision of determination of the frost formation state of the evaporator 5 can be improved.

  Other features are the same as those in the first embodiment.

(Third embodiment)
Another example of the defrosting operation of the refrigerator according to the present invention will be described with reference to the drawings. FIG. 10 is a flowchart showing another example of the defrosting operation of the refrigerator according to the present invention. The flowchart shown in FIG. 10 is the same as the flowchart shown in FIG. 7 except for some differences, and a detailed description of the operation of the same part is omitted. Moreover, the refrigerator Rf of this embodiment has the characteristics in a defrost operation, and has the same structure as refrigerator Rf of 1st Embodiment and 2nd Embodiment.

  In the first embodiment and the second embodiment, the defrosting operation is performed every time a certain time (for example, 24 hours) elapses. However, when the door 114, the door 121, the door 131, and the refrigeration door 27 of the refrigerator Rf are not opened and closed, external high-temperature air does not flow into each storage chamber of the refrigerator Rf. Thereby, even if the cooling device is operated for a long period of time, frost formation is unlikely to occur in the evaporator 5. Besides this, depending on the articles stored in the refrigerator Rf, the humidity of the return air may not easily increase. Even in such a case, frost formation is unlikely to occur in the evaporator 5.

  Therefore, in the refrigerator Rf of the present embodiment, the periodic defrosting operation, that is, the defrosting operation is performed at regular intervals, and the measurement is performed by the first temperature sensor 61 and the second temperature sensor 62 of the evaporator 5. The defrosting operation is performed based on the temperature h1 and the measured temperature h2. When the temperature difference between the upper part and the lower part of the evaporator 5 is small, it is determined that the amount of frost formation in the evaporator 5 is large, and the defrosting operation is performed. Even when the defrosting start time has been reached, if the temperature difference between the upper and lower parts of the evaporator 5 is large, it is determined that the amount of frost formation is small, and the defrosting start is delayed. In the refrigerator Rf of the present embodiment, the defrosting operation is performed under such conditions.

  In the refrigerator Rf of the present embodiment, the first temperature sensor 61 measures the measured temperature h1 and the second temperature sensor 62 measures the measured temperature h2 and stores them in the storage unit Mem at regular intervals (for example, 1 minute). ing. The control unit Cont acquires the measurement temperature h1 and the measurement temperature h2 that have been measured most recently (step S301). The controller Cont calculates a difference value d3 (= | h2−h1 |) between the measured temperature h1 and the measured temperature h2 (step S302). The controller Cont checks whether or not the current foreign country is a time before the scheduled defrost start time (step S303).

  If the current time is before the scheduled start time for defrosting (Yes in step 303), periodic defrosting is not performed, and the controller Cont determines whether the difference value d3 is smaller than the third threshold th3. It is confirmed whether or not (step S304). When the difference value d3 is greater than or equal to the threshold th3 (No in step S304), it is determined that the amount of frost formation in the evaporator 5 is small, and the control unit Cont returns to step S301, and the latest measured temperature h1 and measured temperature. Get h2.

  When the difference value d3 is smaller than the threshold th3 (Yes in step S304), the control unit Cont determines that defrosting of the evaporator 5 is necessary, and even before the scheduled defrosting scheduled time. Then, the glass tube heater 7 is driven to start the defrosting operation (step S305). When the amount of frost formation is large, the controller Cont determines whether or not the measured temperature h1 of the first temperature sensor 61 that measures the temperature of the upper part of the evaporator 5 that becomes low temperature during normal operation exceeds a predetermined temperature a2. (Step S107). Thereafter, the defrosting operation is completed with the same operation as the flowchart shown in FIG.

  When the defrost start time has been reached or the defrost start time has passed (No in step S303), the controller Cont checks whether or not the difference value d3 is greater than the fourth threshold th4 (step S306). ). When the difference value d3 is larger than the fourth threshold th4 (Yes in step S306), the frosting amount of the evaporator 5 is determined to be very small and defrosting is unnecessary, and the control unit Cont proceeds to step S301. Returning, the latest measurement temperature h1 and measurement temperature h2 are acquired.

  When the difference value d3 is equal to or smaller than the fourth threshold th4 (No in Step S306), the control unit Cont checks whether or not the difference value d3 is larger than the first threshold Th1 (Step S307). If the difference value d3 is greater than the first threshold Th1 (Yes in step S307), it is determined that the amount of frost formation in the evaporator 5 is small. Thereafter, the glass tube heater 7 is driven (step S308). When the amount of frost formation is small, the control unit Cont checks whether or not the measured temperature h2 of the second temperature sensor 62 that measures the temperature of the lower part of the evaporator 5 exceeds a predetermined temperature a1 (step S105). . Thereafter, the defrosting operation is completed with the same operation as the flowchart shown in FIG.

  As described above, in the refrigerator Rf of the present embodiment, the defrosting start timing is advanced (accelerated) by the temperature difference between the upper part and the lower part of the evaporator 5 while having the setting for performing the regular defrosting operation. ) Or delay (delay). Even when the defrosting operation is performed, the amount of frost formation is determined based on the temperature of the evaporator 5, and the defrosting operation is performed for a long time on the basis of the first temperature sensor 61, or the second temperature sensor 62. To determine whether to perform defrosting for a short time.

  In the refrigerator Rf of the present embodiment, when the defrosting operation is performed, the control unit Cont stores that the defrosting operation has been performed, and then, after a predetermined time has elapsed (after 24 hours have elapsed). May be set as the next defrosting start time. In addition, when the defrosting operation is performed at a timing other than the regular defrosting operation, when the defrosting operation is started before the regular defrosting time, it is attached to the evaporator 5. You may judge that it is in the state which is easy to frost, and may change the space | interval of defrosting short. Further, when the defrosting operation is performed at a timing later than the regular defrosting timing, it may be determined that the evaporator 5 is not easily frosted, and the defrosting interval may be changed to be longer. .

  By performing such a defrosting operation, a decrease in the capacity of the cooling device is suppressed by frost formation on the evaporator 5. Further, unnecessary power consumption can be suppressed by not performing an unnecessary and urgent defrosting operation.

  Further, in this embodiment, in addition to the regular defrosting operation, the defrosting operation is advanced by the temperature difference between the upper part and the lower part of the evaporator 5 (before the time of the regular defrosting operation is reached). ) Or delay (delaying the defrosting operation after the regular defrosting operation time). However, only one of them may be used.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to this content. The embodiments of the present invention can be variously modified without departing from the spirit of the invention.

Rf Refrigerator 100 Heat insulation box 101 Partition shelf 102 Machine room 103 Through hole Comp Compressor 1 First space 2 Second space 11 Lower freezing chamber 111 First storage case 112 Second storage case 113 Third storage case 114 Door 12 Upper stage freezing Chamber 121 Door 122 Storage case 13 Ice making chamber 131 Door 132 Storage case 133 Ice making machine 14 Bulkhead 21 Refrigeration chamber 22 Chilled chamber 221 Storage case 222 Front door 23 Vegetable room 231 Storage case 232 Front door 24 Movable shelves 25, 26 Fixed shelf 27 Refrigerating door 271 Door pocket 28 Bulkhead 3 Cold air passage 30 Partition member 31 Cold air generating part 32 Cold air ducts 321, 322, 323, 324 Discharge port 33 Refrigeration fan 34 Refrigeration return duct 4 Cold air flow path 41 Damper 42 Refrigeration fan 43 Discharge port 44 Refrigeration Return duct 441 Return opening 442 Return port 5 Evaporator 5 Pipe 52 fin 61 first temperature sensor 62 second temperature sensor 7 glass tube heater 71 heater cover Cont controller Mem storage unit CL timing section

Claims (5)

A refrigerator that cools a storage room with air cooled by circulating in an evaporator,
A first temperature measuring unit for measuring a temperature downstream of the evaporator in the air flow direction;
A second temperature measuring unit for measuring a temperature upstream of the evaporator in the air flow direction;
A heating device for heating the evaporator;
A control unit that obtains a measurement temperature from the first temperature measurement unit and the second temperature measurement unit and controls the heating device;
The control unit operates the heating device to perform a defrosting operation to melt the frost of the evaporator, and the first temperature measured by the first temperature measurement unit before the start of the defrosting operation, The second temperature measured by the second temperature measurement unit is acquired, and when the difference value, which is the difference between the first temperature and the second temperature, is larger than the first threshold, it is based on the measurement temperature of the second temperature measurement unit. The defrosting operation is terminated, and the defrosting operation is terminated based on the measured temperature of the first temperature measurement unit when the difference value is equal to or less than the first threshold value. A return port for returning air from the storage chamber to the upstream side of the evaporator;
The refrigerator according to claim 1, wherein the second temperature measurement unit measures a temperature at a location downstream of the surface of the evaporator facing the return port. The storage room includes a refrigerator room for storing articles at a low temperature and a freezer room for storing articles frozen at a temperature lower than the refrigerator room,
The refrigerator according to claim 1 or 2, wherein the control unit acquires the first temperature and the second temperature during a period in which air circulated through the evaporator cools the refrigerator compartment. The return port includes a refrigerating chamber return port for returning air from the refrigerating chamber to the evaporator,
The refrigerator according to claim 3, wherein the second temperature measurement unit measures a temperature in the vicinity of the refrigerator compartment return port.   The said control part is a refrigerator in any one of Claims 1-4 which delays the start of a defrost operation, when the said difference value is larger than the 2nd threshold value larger than a 1st threshold value.

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