JP2017215108A - refrigerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigerator having a simple structure, capable of efficiently performing defrosting operation for eliminating frosting of an evaporator, and capable of reducing power consumption.SOLUTION: A refrigerator Rf configured to cool inside with air cooled by flowing through an evaporator 5, includes a first temperature measurement unit 61 capable of measuring a temperature of air flowing through the evaporator 5. A control unit Cont is configured to acquire a first measurement temperature H1 from the first temperature measurement unit 61, and when the first measurement temperature H1 is lower than a first threshold Th1 lower than a lower limit temperature at which the refrigeration chamber can be maintained, stop a compressor Comp and start defrosting operation for driving a heating device 7.SELECTED DRAWING: Figure 7

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 an interior with cooled air, the compressor being connected to an evaporator and driving a refrigeration cycle, and an air flow inside the evaporator. A blower that generates air that is cooled by generating, a freezing chamber that is maintained at a temperature at which articles can be stored frozen by the cooled air, and a first that can measure the temperature of the air flowing through the evaporator A temperature measurement unit; a heating device that heats the evaporator; and a control unit that acquires a first measurement temperature from the first temperature measurement unit, wherein the control unit is acquired from the first temperature measurement unit. Provided is a refrigerator that starts a defrosting operation that stops the compressor and drives the heating device when a first measured temperature is lower than a first threshold value that is lower than a lower limit temperature at which the freezer compartment is maintained. it can.

  According to this configuration, the temperature of the air flowing through the evaporator is measured by the first temperature measurement unit. In the first temperature measurement unit, when the amount of frost formation on the evaporator is large, the first temperature measurement unit is affected by the frost temperature (measures the frost temperature). Since there is a gap between the temperature of the air flowing through the evaporator and the temperature of frost, it is determined whether or not frost is formed based on the measured temperature.

  By using such a change in the measured temperature from the temperature measuring unit, it is possible to accurately acquire the frosting state of the evaporator without using a special device for detecting the frosting amount. is there. Moreover, since a frost formation state can be acquired correctly, it becomes possible to perform defrosting reliably when necessary, and it is possible to suppress a decrease in cooling capacity due to the occurrence of clogging and to reduce energy consumption.

  In the above configuration, the evaporator includes a refrigerant pipe through which a low-temperature refrigerant flows, and a fin disposed in contact with the refrigerant pipe. The first temperature measurement unit includes the refrigerant pipe and It may be arranged away from the fins. In the evaporator, a low-temperature refrigerant flows through the refrigerant pipe, and frosting starts from the surface of the refrigerant pipe and / or the fin. By disposing the first temperature measuring unit away from the refrigerant pipe and the fin, even if frosting occurs on the refrigerant pipe and the fin, the first temperature measuring unit is configured to install the evaporator until a certain amount of frost adheres. Measurement of the temperature of flowing air is possible. That is, it is possible to determine a state where frost is formed but no eye clogging occurs, and execution of the defrosting operation in a state where no clogging occurs can be suppressed. In the refrigerator, the defrosting operation may be performed every time a certain period of time elapses. In this case, the defrosting operation is performed even if the amount of frost formation is small. Here, the first temperature setting section is arranged “separated” from the fin, but this “separated” means “thermally separated”. Therefore, the thing which separated the space physically and the thing which the member to isolate | separate thermally interpose are included.

  The said structure WHEREIN: The said 1st temperature measurement part may be attached to the said refrigerant | coolant piping via the attachment member whose heat conductivity is lower than the said refrigerant | coolant piping. According to this configuration, heat transfer between the first temperature measurement unit and the refrigerant pipe can be suppressed and it is easy to fix the heat tightly. Thereby, when there is no eye clogging due to frost formation, the temperature measured by the first temperature measuring unit is not easily affected by the temperature of the refrigerant pipe.

  The said structure WHEREIN: The return port which returns the air which cooled the said inside to the said upstream of the said evaporator is provided, and the said 1st temperature measurement part is arrange | positioned downstream from the surface facing the said return port of the said evaporator May be.

  The said structure WHEREIN: The 2nd temperature measurement part which can measure the temperature of the air which flows through the said evaporator is further provided, and the said 2nd temperature measurement part is a position far from the said 1st temperature measurement part seeing from the said heating apparatus. When the defrosting operation is performed, the control unit is acquired from the second temperature measurement unit when the first measurement temperature is higher than a predetermined third threshold value. The defrosting operation is terminated when the second measured temperature is higher than the fourth threshold value lower than the third threshold value, and when the second measured temperature is lower than the fourth threshold value, the second measured temperature is You may make it complete | finish, after continuing a defrost operation until it becomes higher than the 5th threshold value higher than the said 4th threshold value.

  According to this configuration, the temperature of air flowing through different positions of the evaporator is measured by the two temperature measuring units, and the frosting state of the evaporator is determined based on the measurement result. Is possible to get. And since it performs a defrost operation so that it may respond | correspond to an exact frosting state, it is possible to perform a defrost operation without excess and deficiency.

  In the above configuration, when the first measured temperature is lower than the first threshold, the control unit stops the compressor, continues the stop state for a predetermined waiting time, and then acquires the compressor. When the difference between the first measured temperature and the first measured temperature when the compressor is stopped is equal to or smaller than a predetermined difference value, the heating device may be driven to start the defrosting operation. According to this configuration, even if it is determined that the clogging due to frost occurs based on the temperature measured by the first temperature measurement unit, the temperature is a factor other than frost formation (rising of outside air temperature, It may occur during storage of high-temperature items, door opening / closing, etc.). By providing the standby time, it is possible to remove the determination that the eye is clogged due to factors other than the eye clogging and to prevent unnecessary defrosting operation from being performed.

  The said structure WHEREIN: The said control part may drive the said air blower during the said standby | waiting time.

 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 an enlarged view of the evaporator of the state which attached the 1st temperature sensor to the curved part of a pipe. It is an enlarged view of the evaporator of the state which attached the 1st temperature sensor to the linear part of the pipe. It is a figure which shows the 1st temperature sensor of the state which is not frosting. It is a figure which shows the 1st temperature sensor of the state which has partially frosted. It is a figure which shows the 1st temperature sensor of the state which has produced the eye clogging by frost formation. 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 block diagram of the further another example of the refrigerator concerning this invention. It is the schematic of the evaporator with which the refrigerator concerning this invention is equipped. It is a flowchart which shows the procedure which performs a defrost driving | operation with the refrigerator shown in FIG.

  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 refrigeration compartment 1 and the upper side is the refrigeration compartment 2. In the refrigerator Rf, the refrigeration compartment 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 refrigerated compartment 2 is provided with a storage room that is maintained at a temperature lower than the outside and at a temperature at which articles are not easily frozen (for example, about 0 ° C. to about 8 ° C.).

  As shown in FIGS. 1 and 2, the freezing compartment 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 freezing compartment 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.

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

  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 rectifying plate 14 is provided on the back side of the refrigeration compartment 1. A partition member 30 is further provided behind the current plate 14. Between the rectifying plate 14 and the partition member 30, a cold air duct 32 through which cool air for cooling the lower freezer compartment 11, the upper freezer compartment 12, and the like is provided. As shown in FIG. 1, the refrigeration compartment 1 of the heat insulation box 100 is provided with a groove extending vertically in the center portion, and the rectifying plate 14 and the partition member 30 cover the front of the groove. The gap between the current plate 14 and the partition member 30 and the groove is a cold air duct 32.

  A gap between the partition member 30 and the wall surface on the back side of the freezing compartment 1 is the cold air flow path 3. An evaporator chamber 31 is provided in the cold air flow path 3 to generate cold air for cooling the refrigerator Rf during the cooling operation. The evaporator chamber 31 is provided with an evaporator 5 that is a cooler of the refrigerator Rf and a refrigeration 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 flow path 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 evaporator chamber 31. That is, by operating the refrigeration fan 33, the airflow flows through the evaporator 5. In the refrigerator Rf, the refrigeration fan 33 operates when the cooling device is performing a cooling operation.

  The cold air flow path 3 is connected to the cold air duct 32 at the upper part. The cold air generated in the evaporator chamber 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 which are through holes formed in the current plate 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 inside of the freezer compartment 1 returns to the evaporator chamber 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 evaporator chamber 31 below the evaporator 5. That is, the cold air that has cooled the lower freezing chamber 11, the upper freezing chamber 12, and the ice making chamber 13 flows through the return duct 34, enters the cold air flow path 3, and returns to the evaporator chamber 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 refrigerated compartment 2 is provided with a refrigerated chamber 21, a chilled chamber 22, and a vegetable chamber 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. Moreover, the chilled chamber 22 is maintained at a temperature (for example, 2 ° C. to −1 ° C.) that is lower than the refrigerated chamber 21 and that makes it difficult for articles to freeze. The vegetable room 23 is maintained at a temperature (for example, 5 ° C. to 8 ° C.) that suppresses low-temperature damage to vegetables. In addition, these storage rooms and its maintenance temperature are an example, the range of the temperature which articles | freezes may be sufficient, and the storage room of temperature different from these may be provided.

  The front side of the refrigeration compartment 2 is open, and a refrigeration door 27 is provided on the front side so as to be openable and closable. The refrigeration door 27 is pivotally supported by the heat insulating box 100 and rotates around the support shaft to open and close the opening of the refrigeration section 2. In addition, the refrigerator door 27 may be capable of closing the opening of the refrigerator compartment 2 with one member (door), or may be capable of closing with two or more members (doors). . Here, it is the refrigerator door 27 which can block the opening of the refrigerator compartment 2 by 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 refrigeration door 27, a door pocket 271 is provided for storing bottles, cans, paper packs and the like standing up.

  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 that flows in from the return opening 441 flows into the refrigerated return duct 44.

  As shown in FIG. 2, a rectifying plate 28 is provided in the back of the refrigerated compartment 2. A cold air duct 4 through which cold air for cooling the refrigerator room 21, the chilled room 22, and the vegetable room 23 flows is provided between the rectifying plate 28 and the inner wall surface of the refrigerator compartment 2. As shown in FIG. 1, the refrigerated compartment 2 of the heat insulation box 100 is provided with a groove extending vertically in the center portion, and the rectifying plate 28 covers the front of the groove. The gap between the current plate 28 and the groove becomes the cold air duct 4.

  The cold air duct 4 includes a damper 41, a refrigeration fan 42, and a discharge port 43. The damper 41 opens and closes the through-hole 103 provided in the partition shelf 101 as necessary, and adjusts the inflow of cold air from the cold air flow path 3. The refrigeration fan 42 is a blower for pushing away the cool air that flows in by opening the damper 41. The cold air rises in the cold air duct 4 by the operation of the refrigeration fan 42. The discharge port 43 is a through hole provided in the rectifying plate 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 that has flowed through the cold air duct 4 flows into the refrigerating chamber 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 chamber 23 flows through the refrigeration return duct 44, returns to the cold air flow path 3, and is guided to the evaporator chamber 31 in which the evaporator 5 is provided. The cold air that has cooled the refrigeration section 2 and has flowed into the refrigeration return duct 44 may be referred to as refrigeration return cold air.

  The refrigeration return duct 44 penetrates the partition shelf 101 from the back side of the vegetable compartment 23 and extends downward to the back side of the freezing compartment 1. The refrigerated return duct 44 includes a return opening 441 and a return port 442. Similar to the cold air duct 4, the refrigeration return duct 44 is formed in a space sandwiched between the groove and the rectifying plate 28. The return opening 441 is a through hole that penetrates the current plate 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 evaporator chamber 31 of the cool air flow path 3 from the lower right side of the evaporator 5.

  In the cooling device for the refrigerator Rf according to the present invention, the single evaporator 5 cools all the storage rooms. The cool air flow path 3 and the cool air duct 4 are communicated with each other through the through hole 103 of the partition shelf 101, and the amount of cool air generated in the cool air flow path 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 cold air generated in the evaporator chamber 31 circulates in the refrigeration compartment 1. Further, when the cooling device is operating with the damper 41 open, the cold air circulates through both the freezing compartment 1 and the refrigerated compartment 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 heat from the air which flows around the evaporator 5 by the heat of vaporization by evaporation of a refrigerant | coolant. 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 evaporator chamber 31 in which the evaporator 5 is provided 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 receives heat from internal articles and air in each storage chamber of the refrigerator Rf. Therefore, the temperature of the return cold air is higher than when it is generated in the evaporator chamber 31. Then, when the return cold air flows upward in the evaporator 5, it is cooled again and sent to each storage room as cold air.

  The return cold air may evaporate the dew adhering to the food or the cabinet when the temperature is raised by taking heat from the article or air in each storage room. Therefore, the return cold air may contain more water vapor than the cold air generated in the evaporator 5. When such return cold air is cooled again by the evaporator 5, the water vapor contained in excess of the saturated water vapor amount aggregates in the pipe 51 and the fins 52. As described above, the evaporator 5 generates cold air that can cool the lower freezer compartment 11 and the upper freezer compartment 12, and the temperatures of the lower freezer compartment 11 and the upper freezer compartment 12 are lower than the melting point of water (0 ° C.). . Therefore, the water condensed on the pipe 51 and the fin 52 is solidified and adheres as frost.

  And if the time which continues driving | running becomes long, the adhesion amount of frost will increase and the eyes of the fin 52 will generate | occur | produce by frost. When the fins 52 are clogged, it becomes difficult for air to flow through the evaporator 5, and 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. In the refrigerator Rf, a defrosting operation is performed at regular intervals, that is, periodically to ensure a stable cooling capacity for a long period of time. Details of the defrosting operation will be described later.

  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. Connected to the part Cont. 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.

  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 measurement unit) that measures the temperature of the air flowing through the evaporator 5 and a glass tube heater 7 (heating device) that heats the evaporator 5 during the defrosting operation. ). A refrigeration fan 33 is provided above the evaporator 5. In the evaporator 5, air is sucked up by the refrigeration fan 33, so that the air flows upward from below. Therefore, the return port 442 of the refrigeration return duct 44 opens below the evaporator 5.

  Further, 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).

  The first temperature sensor 61 is provided at an intermediate portion in the vertical direction of the evaporator 5. In the present embodiment, the first temperature sensor 61 measures the temperature of the air flowing through the evaporator 5. Therefore, when the cold air is directly blown back to the first temperature sensor 61, it is difficult to measure the exact temperature of the air flowing through the evaporator 5 due to the influence of the temperature of the return cold air. Therefore, it is preferable that the first temperature sensor 61 is at a position where the return cold air is not directly blown, that is, a position not facing the return port 442 in the flow direction of the return cold air from the return port 442 of the refrigeration return duct 44. Furthermore, the first temperature sensor 61 is more preferably located at a position that does not directly face the return port 442 of the refrigeration return duct 44.

  Moreover, in this embodiment, the 1st temperature sensor 61 detects the amount of frost formation of the evaporator 5 as mentioned later. Since the return port 442 of the refrigeration return duct 44 opens below the evaporator 5 and flows from the lower part to the upper part in the evaporator 5, the water vapor exceeding the saturated water contained in the return cold air flows under the evaporator 5. First, the pipe 51 and the fin 52 are aggregated to form frost. Therefore, since the evaporator 5 forms frost in order from the lower part, when frost formation is detected at the upper part of the evaporator 5, the amount of frost formed so as to hinder the cooling capacity of the evaporator 5 at the lower part of the evaporator 5. There is a risk of becoming.

  Therefore, in the present embodiment, it is preferable that the first temperature sensor 61 is positioned below the evaporator 5 and not to face the return port 442 of the refrigeration return duct 44. In FIG. 4, the temperature of the air flowing through a position (for example, an intermediate portion) shifted from the lower end portion (upstream end in the air flow direction) of the evaporator 5 to the upper portion (downstream direction) is measured.

  Further, even during the defrosting operation, when the first temperature sensor 61 is provided at the lower end, the heat of the glass tube heater 7 is directly measured or the influence of the air heated by the glass tube heater 7. May be received. Therefore, at the lower end of the evaporator 5, it is often difficult to measure the exact temperature of the air flowing through the evaporator 5. Also from this, it is preferable that the first temperature sensor 61 is disposed at a position shifted upward from the lower end of the evaporator 5.

  The attachment of the first temperature sensor 61 will be described with reference to the drawings. FIG. 5A is an enlarged view of the evaporator with the first temperature sensor attached to the curved portion of the pipe. In the evaporator 5, air flows through a portion between curved portions at both ends of a pipe 51 provided in a meandering manner. As shown in FIG. 5A, the first temperature sensor 61 is disposed inside the curved portion of the pipe 51. Although details will be described later, in the present invention, the temperature of the air flowing inside the evaporator 5 is measured, and it is determined whether or not to perform defrosting based on the measurement result. When the cooling device is operating, the pipes 51 and the fins 52 of the evaporator 5 are at a lower temperature than the air flowing through the evaporator 5. And in order to measure the temperature of the air which flows through the inside of the evaporator 5 correctly, it is preferable that the 1st temperature sensor 61 is arrange | positioned in the state away from the pipe 51 and the fin 52. FIG.

  As shown in FIG. 5A, the first temperature sensor 61 is arranged, that is, fixed inside the curved portion of the pipe 51 via the spacer 63. The spacer 63 is made of a material having low thermal conductivity such as resin or ceramic. And the 1st temperature sensor 61 is being fixed in the state which the measurement part which measures temperature is not wrapped in the spacer 63 or other holding members. The first temperature sensor 61 is fixed in a state where it is exposed to the air flowing inside the evaporator 5, in other words, in a state where it can be in direct contact with the air flowing inside the evaporator 5. By fixing in this way, when measuring the temperature of the air flowing inside the evaporator 5, it is difficult to be influenced by the temperature of the pipe 51 and the fin 52, and the accurate temperature of the air can be measured. It is. In addition, although the distance of the 1st temperature sensor 61, the pipe 51, and the fin 52 can mention about 5 mm, for example, it is not limited to this.

  Further, as shown in FIG. 5B, the attachment position of the first temperature sensor 61 is not limited to the curved portion, and may be fixed to the straight portion of the pipe 51 via the spacer 63. As shown in FIG. 5B, when the first temperature sensor 61 is attached to the straight portion of the pipe 51, the fin 52 of the portion to which the first temperature sensor 61 is attached is removed. However, the present invention is not limited to this, and in the case of the first temperature sensor 61 having a size that can be disposed in the gap between the fins 52, the fins 52 may not be removed. In addition, when attaching the 1st temperature sensor 61 larger than the clearance gap between fins 52, it is possible to reduce the process of the fin 52 by attaching to a curved part.

  5A and 5B are attached to the pipe 51, but the present invention is not limited to this, and the fin 52 may be attached via the spacer 63. However, since the fin 52 is a thinner and weaker member than the pipe 51, it is preferable to attach the first temperature sensor 61 to the pipe 51 in consideration of firmly fixing the first temperature sensor 61. In the following embodiment, it is assumed that the first temperature sensor 61 is attached to the pipe 51.

  In the present embodiment, the spacer 63 that firmly holds the first temperature sensor 61 is used as an attachment for attaching the first temperature sensor 61 to the evaporator 5, but is not limited thereto. For example, the first temperature sensor 61 may be supported by a wire, a plate, or the like. As the attachment, a member that can be attached while suppressing contact between the first temperature sensor 61 and the pipe 51 and the fin 52 can be widely used.

  For example, if the door is opened for a long time or if the article is stored at a high temperature or easily evaporates, the moisture contained in the return cold air becomes larger than that during normal operation. And if the return cold air with much moisture 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, the control unit Cont performs a defrosting operation based on the first measured temperature from the first temperature sensor 61 in addition to the defrosting operation that is periodically performed.

  After describing the state of the first temperature sensor 61 arranged in the evaporator 5 with reference to the drawings, the defrosting operation based on the first measured temperature from the first temperature sensor 61 will be described. FIG. 6A is a diagram illustrating the first temperature sensor in a state where frost is not formed, FIG. 6B is a diagram illustrating the first temperature sensor in a state in which frost is partially formed, and FIG. It is a figure which shows the 1st temperature sensor of the state which has generate | occur | produced.

  For example, consider a case where the lower freezer compartment 11 and the upper freezer compartment 12 are cooled. The lower freezer compartment 11 and the upper freezer compartment 12 are maintained at a temperature t1 (−18 ° C.). Therefore, the cold air that is the air that has flowed through the evaporator 5 has a temperature t2 (−20 ° C.) lower than the temperature t1. Further, the evaporator 5 generates cold air at a temperature t2 through heat exchange between the refrigerant flowing inside and the air. Therefore, the pipe 51 and the fin 52 are at a temperature t3 (−25 degrees) that is lower than the temperature t2.

  As shown to FIG. 6A, when there is no frost in the pipe 51 and the fin 52, the pipe 51 and the fin 52 and the 1st temperature sensor 61 are fully separated. Since the spacer 63 has a low thermal conductivity, there is almost no heat transfer between the pipe 51 and the first temperature sensor 61. Therefore, when there is no frost formation, the first measurement temperature (H1) measured by the first temperature sensor 61 is the temperature of the cold air flowing through the evaporator 5, that is, the temperature t2.

  As shown to FIG. 6B, when there exists frost in a part of pipe 51 and the fin 52, the pipe 51 and the fin 52 and the 1st temperature sensor 61 are fully separated. However, the distance from the surface of the attached frost to the first temperature sensor 61 is shortened. The surface temperature of the frost may be considered to be substantially the same as the temperature of the pipe 61 and the fin 52, and the first measurement temperature H1 measured by the first temperature sensor 61 is slightly lower than the temperature t2 of the cold air flowing through the evaporator 5. Become. And if the amount of frost formation increases, the distance from the 1st temperature sensor 61 of frost to the surface of frost will become short. Thereby, the 1st measurement temperature H1 becomes low as the amount of frost formation increases.

  Then, as shown in FIG. 6C, when the frosting progresses to such an extent that the evaporator 5 is clogged, the entire first temperature sensor 61 is covered with frost. At this time, since the evaporator 5 is clogged, it is difficult for air to flow inside. Moreover, even if air flows, since the 1st temperature sensor 61 is covered with frost, it does not contact the flowing air. And as above-mentioned, since frost is the temperature substantially the same as the pipe 51 and the fin 52, when the eyes of the evaporator 5 clogging generate | occur | produces, the 1st measured temperature H1 measured with the 1st temperature sensor 61 is It is the same or substantially the same value as the temperature t3.

  Thus, by attaching the 1st temperature sensor 61 away from the pipe 51 and the fin 52, the 1st measurement temperature H1 measured with the 1st temperature sensor 61 changes with the amount of frost formation. The control part Cont determines that the clogging due to the frost formation of the evaporator 5 has occurred based on the change in the temperature of the first measurement temperature H1, and the defrosting operation is performed in addition to the regular defrosting operation. I do.

  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 controller Cont acquires the first measured temperature H1 measured by the first temperature sensor 61 at a predetermined interval (for example, once every several tens of seconds) while the cooling device is performing the cooling operation. (Step S101).

  The controller Cont checks whether or not the first measured temperature H1 is lower than the first threshold Th1 (Step S102). In the refrigerator Rf, the lower freezer compartment 11 and the upper freezer compartment 12 can adjust the temperature maintained within a certain range. And the pipe 51 and the fin 52 of the evaporator 5 are set to a temperature lower than the lower limit values of the lower freezer compartment 11 and the upper freezer compartment 12, so that the temperature of the cold air flowing through the evaporator 5, that is, the first measured temperature H1. However, it becomes below the lower limit value of the lower freezer compartment 11 and the upper freezer compartment 12, and the lower freezer compartment 11 and the upper freezer compartment 12 can be cooled to the lower limit value.

  As described above, when the frost formation amount of the evaporator 5 is small, the air flowing through the evaporator 5 is sufficiently circulated, and the frost formation near the first temperature sensor 61 is also small. The temperature H1 is the temperature of the air flowing through the evaporator 5. When the lower freezer compartment 11 and the upper freezer compartment 12 are at the lower limit value, the evaporator 5 is not cooled any further, so that the temperature of the air flowing in the evaporator 5 becomes the lower limit value of the lower freezer compartment 11 and the upper freezer compartment 12. The temperature will be close.

  On the other hand, when the amount of frost formation in the evaporator 5 is large, as described above, the first measurement temperature H1 is the same as or substantially the same as the pipe 51 or the fin 52 of the evaporator 5. Therefore, the first threshold value Th1 is set to a value lower than the lower limit values of the lower freezer compartment 11 and the upper freezer compartment 12. The lower limit of the lower freezer compartment 11 and the upper freezer compartment 12 is, for example, a temperature at which the compressor Comp is turned off.

  Further, the first threshold Th1 can be set to a value lower than the lower limits of the lower freezer compartment 11 and the upper freezer compartment 12 by a predetermined temperature. When the temperature of the lower freezer compartment 11 and the upper freezer compartment 12 is cooled to near the lower limit value, the air temporarily flowing in the evaporator 5 becomes slightly lower than the lower limit values of the lower freezer compartment 11 and the upper freezer compartment 12. Even in such a case, it is possible to prevent unnecessary defrosting by setting a predetermined temperature, for example, 2 ° C.

  Further, the first threshold value Th1 may be a value higher than the temperatures of the pipes 51 and the fins 52 of the evaporator 5 during the cooling operation, thereby defrosting the entire first temperature sensor 61 before it is covered with frost. be able to. In the above example (t1 = −18 ° C., t3 = −25 ° C.), the first threshold Th1 can be set to −21 ° C., for example, but is not limited thereto.

  When the first measured temperature H1 is higher than the first threshold Th1 (No in Step S102), the control unit Cont confirms whether a certain time has elapsed since the end of the previous defrosting operation (Step S103). Step S103 is a step for performing a regular defrosting operation. When the fixed time has not elapsed since the end of the previous defrosting operation (No in step S103), the operation returns to the normal operation.

  When the first measured temperature H1 is lower than the first threshold Th1 (Yes in step S102), the control unit Cont determines that the evaporator 5 is clogged by frost formation, and performs the defrosting operation. Start. Further, the defrosting operation is similarly started when a predetermined time has passed since the end of the previous defrosting operation (Yes in step S103). If Yes in step S102 or Yes in step S103, the control unit Cont stops the compressor Comp (step S104). Note that this step is omitted when the compressor Comp has already stopped.

  After stopping the compressor Comp, the controller Cont energizes the glass tube heater 7 and starts operation of the glass tube heater 7 (step S105). The defrosting operation is started by driving the glass tube heater 7. At this time, as described above, the controller Cont stops the refrigeration fan 42 and the freezing fan 33 and closes the damper 41.

  The control part Cont periodically acquires the first measured temperature H1 from the first temperature sensor 61 (step S106). And the control part Cont confirms whether 1st measured temperature H1 is higher than 2nd threshold value Th2 (step S107). When the first measured temperature H1 is lower than the second threshold Th2 (when Step S107 is No), the controller Cont determines that frost remains in the evaporator 5, and the first measured temperature H1 and the third threshold. The comparison with Th3 (that is, step S106 to step S107) is repeated, and the defrosting operation is continued. If the first measured temperature H1 is higher than the second threshold Th2 (Yes in step S107), the control unit Cont determines that all the frost in the evaporator 5 has melted, and stops the glass tube heater 7 ( Step S108) and return to normal operation.

  The second threshold Th2 is a threshold for confirming that the frost adhering to the evaporator 5 has melted. As shown in FIG. 1, FIG. 2, etc., the glass tube heater 7 is arranged separately below the evaporator 5. Therefore, in the evaporator 5, it melt | dissolves from the frost adhering to the lower part. Since the frost begins to melt at 0 ° C., it can be seen that if the first measurement temperature H1 exceeds 0 ° C., the frost attached to the periphery of the first temperature sensor 61 has melted. Since the 1st temperature sensor 61 is provided in the middle part of the up-and-down direction of evaporator 5, if the whole evaporator 5 is clogged with frost before defrosting, the 1st measurement temperature H1 is 0 ° C. In some cases, the upper part of the evaporator 5 may be clogged with frost. Therefore, the second threshold Th2 can be a temperature (for example, 10 ° C.) higher than the temperature at which the frost melts. The second threshold Th2 varies depending on the size of the evaporator 5 and the position where the first temperature sensor 61 is attached. For example, after defrosting the entire surface of the evaporator 5, defrosting is performed by the glass tube heater 7, and the measured value of the first temperature sensor 61 when it is confirmed that all the frost has melted is used as the second threshold Th <b> 2. Also good.

  With such a configuration, the first temperature sensor 61 can detect not only the melting of the frost that has formed on the evaporator, but also the frosted state of the evaporator. In addition to the typical defrosting operation, even if the eyes are caused by sudden frosting or the frost that cannot be sufficiently removed by the regular defrosting operation grows and eyes are clogged in the evaporator 5 Defrosting can be performed quickly. Thereby, it is possible to reduce energy consumption (electric power) of the refrigerator Rf by suppressing a decrease in cooling capacity due to the clogging of the evaporator 5 and suppressing a decrease in ability to store articles at a low temperature, thereby saving energy. .

  Moreover, even if it is a case where periodic defrost operation is performed, since it is judged whether defrost was completed based on 1st measured temperature H1 measured with the 1st temperature sensor 61, it is not excessive and insufficient. Defrosting operation is possible.

(Second Embodiment)
Another example of the refrigerator according to the present invention 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. In addition, the structure of refrigerator Rf of this embodiment is the same as refrigerator Rf of 1st Embodiment. Therefore, in this embodiment, it demonstrates using the code | symbol used in 1st Embodiment for each structural member of refrigerator Rf.

  In the refrigerator Rf, the controller Cont controls the capacity of the cooling device, that is, the rotational speed of the compressor Comp, based on the temperature of at least one of the lower freezer compartment 11 and the upper freezer compartment 12. For example, when the set temperature (maintained temperature) of the lower freezer compartment 11 is set to be low, cold air having a lower temperature than that at the normal set temperature is required. Therefore, the control part Cont increases the rotation speed of the compressor Comp and improves the cooling capacity of the cooling device. When the rotational speed of the compressor Comp increases, the temperature of the evaporator 5 decreases, and as a result, the first measured temperature H1 measured by the first temperature sensor 61 also decreases.

  In the refrigerator Rf, the set temperature of the lower freezer compartment 11 is set to a predetermined lower limit, and when the normal operation is performed, the first threshold Th1 is set so that the first measured temperature H1 does not fall below the first threshold Th1. It is set. However, there is a case where the lower freezing room 11 needs to be rapidly cooled, for example, when storing a high-temperature article, storing a large quantity of articles, or starting a refrigerator. In such a case, the controller Cont may perform a transient operation in which the compressor Comp is rotated at a high rotational speed. In such a case, the first measured temperature H1 may fall below the first threshold Th1 even if frosting (as shown in FIG. 6C) that causes clogging in the evaporator 5 does not occur.

  Therefore, the control unit Cont performs operation control as shown in the flowchart shown in FIG. 8, and can cope with a temporary drop in the first measured temperature H1 when the compressor Comp is operated at a high speed. . The flowchart shown in FIG. 8 includes steps S201 to S204 for verifying the temperature drop of the first measured temperature H1 between step S104 and step S105 of the flowchart shown in FIG. Further, step S205 is added to stop the compressor Comp when it is determined in step S102 that the periodic defrosting operation is started (Yes in step S102). Therefore, in the following description, a different part from the flowchart of FIG. 7 is mainly demonstrated.

  The control unit Cont acquires the first measured temperature H1 measured by the first temperature sensor 61, and checks whether or not the first measured temperature H1 is lower than the first threshold Th1 (step S102). . When the first measured temperature H1 is higher than the first threshold Th1 (No in Step S102), the control unit Cont confirms whether a certain time has elapsed since the end of the previous defrosting operation (Step S103). Step S103 is a step for performing a regular defrosting operation. When the fixed time has not elapsed since the end of the previous defrosting operation (No in step S103), the operation returns to the normal operation. Further, when a certain time has elapsed (in the case of Yes in step S103), the control unit Cont stops the compressor Comp in order to perform the defrosting operation (step S205). Note that this step is omitted when the compressor Comp has already stopped.

  When the first measured temperature H1 is lower than the first threshold Th1 (Yes in step S102), the control unit Cont determines that the evaporator 5 may be clogged due to frost formation and compresses it. The machine Comp is stopped (step S104).

  As described above, the reason why the first measured temperature H1 is lower than the first threshold Th1 may be a temporary case by rapidly cooling the cooling device when eyes are clogged due to frost formation. When the frost is formed and the eyes are clogged, the measured temperature of the first temperature sensor 61 does not change so much even if the compressor Comp is stopped because the frost cannot be dissolved. On the other hand, when the temperature is temporarily lowered, when the compressor Comp is stopped, the temperature measured by the first temperature sensor 61 greatly increases. The control part Cont uses this fact to determine whether or not the evaporator 5 is frosted. That is, after stopping the compressor Comp (step S104), the controller Cont waits in a state where the compressor Comp is stopped until a predetermined time (referred to as standby time T1) elapses (step S201). Note that the waiting time T1 for stopping the compressor Comp can be about several tens of seconds to several minutes. Here, one minute can be mentioned as the waiting time T1.

  When the predetermined time has elapsed (Yes in step S201), the control unit Cont acquires the measured temperature measured by the first temperature sensor 61 as the comparative measured temperature H11 (step S202). The control unit Cont calculates a difference D1 from the first measured temperature H1 obtained immediately before stopping the compressor Comp (obtained in step S101) (step S2) 03). The controller Cont checks whether or not the difference D1 is smaller than the difference threshold value Df1 (step S204). As described above, in the case of a temperature drop due to frost formation, even if the compressor Comp is stopped, the measured temperature of the first temperature sensor 61 does not change much, that is, the difference D1 is small. Therefore, when the difference D1 is smaller than the difference threshold value Df1 (Yes in step S204), the control unit Cont starts the operation of the glass tube heater 7 (step S105) and starts the defrosting operation. Thereafter, the operation is the same as the flowchart shown in FIG.

  When the difference D1 is larger than the difference threshold value Df1 (No in step S204), the control unit Cont returns to the normal operation without performing the defrosting operation.

  As described above, even if the measured temperature acquired from the first temperature sensor 61 is lower than the preset temperature, if the frost is not formed, it is possible to perform the control without performing the defrosting operation. . Thereby, it is possible to suppress unnecessary defrosting operation and to suppress useless energy consumption (energy saving).

  During normal operation, the controller Cont performs control to stop the refrigeration fan 33, but the refrigeration fan 33 may be continuously driven during the standby time T1. By continuing to drive the refrigeration fan 33 in this way, when the temperature is temporarily lowered and no eye clogging occurs, a large amount of air can flow through the evaporator 5, and the comparative measurement temperature Can help raise H11. In addition, when eyes are clogged due to frost formation, air does not easily flow through the evaporator 5, so that the comparative measurement temperature H <b> 11 is not easily affected even if the refrigeration fan 33 is driven.

  Other features are the same as in the first embodiment.

(Third embodiment)
Still another example of the refrigerator according to the present invention will be described with reference to the drawings. FIG. 9 is a block diagram of still another example of the refrigerator according to the present invention. FIG. 10 is a schematic view of an evaporator provided in the refrigerator according to the present invention.

  The refrigerator Rf1 illustrated in FIGS. 9 and 10 includes a second temperature sensor 62 in addition to the first temperature sensor 61 as a temperature measurement unit that measures the temperature of the air flowing through the evaporator 5. In addition, the other parts have the same configuration as the refrigerator Rf shown in the first embodiment, and substantially the same parts are denoted by the same reference numerals and detailed description of the same parts is omitted.

  Since the glass tube heater 7 heats the evaporator 5 from below, heat is supplied to the lower part of the evaporator 5 and transmitted upward during the defrosting operation. Therefore, when the defrosting operation is performed, the lower part of the evaporator 5 is likely to be hotter than the upper part.

  The eyes due to frost formation on the evaporator 5 vary depending on the environment (temperature, humidity) of the refrigerator installation location, stored articles, opening / closing frequency, and the like. For example, frost may adhere to the entire evaporator 5, or may adhere to the upper part or the lower part. When frost is attached to the entire evaporator 5, it is necessary to apply more heat from the glass tube heater 7 than when frost is attached to a part of the evaporator 5. That is, in the case of performing the defrosting operation, it can be said that the conditions are more severe when the frost is attached to the entire evaporator 5 than when the frost is attached to a part thereof.

  In general, a refrigerator is often set to perform a defrosting operation assuming severe conditions, and flows through an intermediate portion of the evaporator 5 as in the first and second embodiments. When the end of the defrosting operation is determined based on the temperature of the air, the second threshold Th2 that determines the end of the defrosting is set high. When the end of the defrosting operation is determined only by the first temperature sensor 61, when the second threshold Th2 is most severe, that is, when all of the frost adhering to the entire evaporator 5 is melted by the glass tube heater 7. The first temperature sensor 61 is set to a temperature equal to or higher than the measured temperature.

  As described above, in the evaporator 5, frost is not always attached to the whole at the start of the defrosting operation. For example, frost formation may be biased to the upper part or the lower part of the evaporator 5, that is, the amount of frost formation may be small as compared with the case where frost is attached to the whole. In order to cope with such a case, the refrigerator Rf <b> 1 of the present embodiment includes a second temperature sensor 62 in addition to the first temperature sensor 61.

  Therefore, in the refrigerator Rf1 of the present embodiment, the temperature of the air flowing through a place where frost is difficult to be melted during the defrosting operation is measured, and the temperature of the air flowing due to the temperature change or the temperature of the pipe 51 or the fin 52 due to frost adhesion Determine whether you are measuring. Therefore, the second temperature sensor 62 is difficult to melt at the time of defrosting, that is, in the vicinity of the place where the frost remains until the end, that is, the place far from the glass tube heater 7 (here, the upper part of the evaporator 5). It is arranged to measure the temperature of the air flowing through the place.

  The second temperature sensor 62 is also attached to the evaporator 5 via a spacer 63 similar to the first temperature sensor 61. However, it is not limited to this, and may be attached to the evaporator 5 by a method different from that of the first temperature sensor 61. For the attachment of the second temperature sensor 62, a method that can be stably arranged in a state of being separated from the pipe 51 and the fin 52 by a certain distance (for example, 5 mm) or more can be widely adopted. In the present embodiment, the second temperature sensor 62 is disposed near the accumulator 53 for temporarily storing the refrigerant that has flowed inside the evaporator 5.

  And in refrigerator Rf1 concerning this embodiment, while the control part Cont starts defrost operation based on 1st measurement temperature H1 measured with the 1st temperature sensor 61, 1st measurement temperature H1 and 2nd The defrosting operation is stopped based on the measured temperature measured by the temperature sensor 62 (here, the second measured temperature H2).

  That is, after the first temperature sensor 61 confirms that the lower part of the evaporator 5 is defrosted, the second temperature sensor 62 confirms that the upper part of the evaporator 5 is defrosted. By doing so, excessive defrosting operation can be suppressed. The procedure of the defrost operation using the above will be described with reference to the drawings. FIG. 11 is a flowchart showing a procedure for performing the defrosting operation in the refrigerator shown in FIG.

  The flowchart shown in FIG. 11 includes steps S301 to S304 for confirming the defrosting state of the upper part of the evaporator 5 based on the second measured temperature H2 between step S107 and step S108 of the flowchart shown in FIG. It has a configuration. Therefore, in the following description, a different part from the flowchart of FIG. 7 is mainly demonstrated. In step S107, the third threshold Th3 is used instead of the second threshold.

  In the flowchart shown in FIG. 11, step S101 to step S106 and step S108 are common. That is, the control part Cont starts the defrosting operation when the first measured temperature H1 becomes lower than the first threshold Th1. And control part Cont acquires 1st measured temperature H1 regularly also during a defrost operation.

  Then, the controller Cont checks whether or not the first measured temperature H1 is higher than the third threshold Th3 (Step S107). The third threshold Th3 may be lower than the second threshold Th2 used in the flowchart shown in FIG. As described above, the second threshold Th2 is a value equivalent to the first measured temperature H1 when all the frost is melted when the entire evaporator 5 is frosted. That is, in the defrosting operation, the threshold value is set on the assumption that the frosting state of the evaporator 5 is the most severe. When frost adheres to only a part of the evaporator 5, the frost may have melted in the entire evaporator 5 until the first measured temperature H1 reaches the second threshold Th2. In consideration of such defrosting when only part of the frost is formed, the third threshold Th3 is looser than the second threshold Th2 in the defrosting operation, that is, at a lower temperature (for example, 5 ° C).

  When the first measurement temperature H1 is lower than the third threshold value Th3 (No in step S107), the control unit Cont determines that frost remains in the evaporator 5, and the first measurement temperature H1 and the third threshold value are determined. The comparison with Th3 (that is, step S106 to step S107) is repeated.

  Further, when the first measured temperature H1 is higher than the third threshold Th3 (Yes in Step S107), the control unit Cont acquires the second measured temperature H2 measured by the second temperature sensor 62 (Step S301). . The second temperature sensor 62 is a sensor that measures the temperature of the air flowing through the upper portion of the evaporator 5, and, like the first temperature sensor 61, eyes are clogged due to frost formation compared to when air is flowing. The second measurement temperature H2 is lowered when Therefore, the control unit Cont checks whether or not the second measured temperature H2 is higher than the fourth threshold Th4 (step S302). The comparison between the second measured temperature H2 and the fourth threshold value Th4 (step S302) is performed to determine whether air is flowing in the vicinity of the second temperature sensor 62, that is, in the upper part of the evaporator 5, or is clogged. It is a step. Therefore, the fourth threshold Th4 can be set to a temperature (for example, 1 ° C.) at which it is understood that the frost has melted.

  When the second measured temperature H2 is higher than the fourth threshold Th4 (Yes in step S302), it can be determined that air is flowing through the upper portion of the evaporator 5, and the control unit Cont stops the glass tube heater 7 ( Step S108), returning to normal operation.

  When the second measured temperature H2 is lower than the fourth threshold Th4 (No in Step S302), the control unit Cont newly acquires the second measured temperature H2 from the second temperature sensor 62 above the evaporator 5. (Step S303). Then, the controller Cont confirms whether or not the second measured temperature H2 is higher than the fifth threshold Th5 (Step S304).

  In the comparison between the second measured temperature H2 and the fifth threshold Th5 (step S304), the defrosting operation is performed to some extent, but it is determined that there is an eye clogging due to frost formation on the top of the evaporator 5. Steps to be executed. Since frost remains after performing the defrosting operation to some extent, it is considered that the amount of frost formation is large or frost formation is partially biased. When such frost formation has occurred, even if it is confirmed that the frost around the second temperature sensor 62 has melted from the second measured temperature H2, the second temperature sensor 62 is far from the glass tube heater 7. It is considered that frost may remain in the part far from the center. Therefore, the controller Cont sets the fifth threshold Th5 to a stricter condition, that is, a higher temperature (for example, 8 ° C.) than the fourth threshold Th4 during the defrosting operation.

  When the second measured temperature H2 is lower than the fifth threshold Th5 (No in step S304), the control unit Cont determines that frost remains in the evaporator 5, and the second measured temperature H2 and the fifth threshold are determined. The comparison with Th5 (that is, step S303 to step S304) is repeated. When the second measured temperature H2 is higher than the fifth threshold Th5 (Yes in step S304), the controller Cont determines that the frost in the evaporator 5 has melted, and the glass tube heater 7 is turned on. Stop (step S108) and return to normal operation.

  In the refrigerator Rf1 according to the present embodiment, the first temperature sensor 61 and the second temperature sensor 62 are attached to the evaporator 5, and the removal is performed based on the first measurement temperature H1 and the second measurement temperature H2 acquired from the respective temperature sensors. It is the structure which determines completion | finish of frost. Thereby, while being able to grasp | ascertain the frost state of the evaporator 5 more correctly and defrosting based on an exact frost state, it is possible to perform a defrost operation without excess and deficiency.

  Other features are the same as in the first embodiment.

  In the present embodiment, if the defrosting operation is not terminated after comparing the second measured temperature H2 and the fourth threshold Th4, the fifth condition is more stringent than the fourth threshold Th4 during the defrosting operation. The threshold is used. However, the present invention is not limited to this. For example, when it can be determined that the surrounding frost has been removed to some extent by comparing the second measured temperature H2 with the fourth threshold Th4, the fourth threshold Th4 is used instead of the fifth threshold Th5. May be used. In this case, the flowchart shown in FIG. 11 has the same configuration as that in which the operation returns to step S301 after No in step S302.

  In the refrigerator according to the present invention described above, the temperature measurement unit (the first temperature sensor 61 or the second temperature sensor 62) flows not inside the evaporator 5 (pipe 51, fin 52) itself but inside the evaporator 5. It is provided to measure the temperature of the air. And if the amount of frost formation of the evaporator 5 increases, a temperature measurement part comes to measure the temperature of frost. Thus, the exact amount of frost formation is acquired using the difference in temperature measured by the temperature measurement unit depending on the frost formation state (frost formation amount). Therefore, it is not necessary to provide a detection unit for detecting the amount of frost formation by image processing, weight, or the like. Since the frost formation state can be determined based on the measurement temperature that is easy to measure and has a small amount of information, the process can be simplified.

  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 Freezing compartment 2 Refrigerated compartment 11 Lower freezer compartment 111 First storage case 112 Second storage case 113 Third storage case 114 Door 12 Upper freezer chamber 121 Door 122 Storage case 13 Ice making room 131 Door 132 Storage case 133 Ice making machine 14 Rectifier plate 21 Refrigeration room 22 Chilled room 221 Storage case 222 Front door 23 Vegetable room 231 Storage case 232 Front door 24 Movable shelves 25, 26 Fixed shelf 27 Refrigeration Door 271 Door pocket 28 Rectifying plate 3 Cold air flow path 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 duct 41 Damper 42 Refrigeration fan 43 Discharge port 44 Refrigeration Return duct 441 Return opening 442 Return port 5 Steam Vessel 51 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 (6)

A compressor connected to the evaporator to drive the refrigeration cycle;
A blower that generates cooled air by generating a flow of air inside the evaporator; and
A freezing room maintained at a temperature at which articles can be stored frozen in the cooled air;
A first temperature measuring unit capable of measuring the temperature of the air flowing through the evaporator;
A heating device for heating the evaporator;
A refrigerator having a control unit for obtaining a first measurement temperature from the first temperature measurement unit,
When the first measurement temperature acquired from the first temperature measurement unit is lower than a first threshold value lower than a lower limit temperature at which the freezer compartment is maintained, the control unit stops the compressor and The refrigerator which starts the defrost driving | operation which drives a heating apparatus. The evaporator has a refrigerant pipe through which a low-temperature refrigerant flows, and a fin arranged in contact with the refrigerant pipe,
The refrigerator according to claim 1, wherein the first temperature measurement unit is arranged to be thermally separated from the refrigerant pipe and the fin. A return port for returning the air cooled inside to the upstream side of the evaporator;
The refrigerator according to claim 1 or 2, wherein the first temperature measurement unit is disposed on a downstream side of a surface of the evaporator that faces the return port. A second temperature measuring unit capable of measuring the temperature of the air flowing through the evaporator;
The second temperature measurement unit is provided at a position farther than the first temperature measurement unit as viewed from the heating device,
When the defrosting operation is being performed, the control unit obtains the second measured temperature acquired from the second temperature measuring unit when the first measured temperature becomes higher than a predetermined third threshold. When the temperature is higher than a fourth threshold value lower than the third threshold value, the defrosting operation is terminated, and when the second measured temperature is lower than the fourth threshold value, the second measured temperature is lower than the fourth threshold value. The refrigerator according to any one of claims 1 to 3, wherein the refrigerator is terminated after the defrosting operation is continued until it becomes higher than a higher fifth threshold value.   The control unit stops the compressor when the first measured temperature becomes lower than the first threshold, continues the stopped state for a predetermined waiting time, and then acquires the first measured temperature. The defrosting operation is started by driving the heating device when a difference between the first measured temperature when the compressor is stopped and a first measured temperature is equal to or less than a predetermined difference value. Refrigerator.   The refrigerator according to claim 5, wherein the control unit drives the blower during the standby time.

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