JP6706146B2 - refrigerator - Google Patents

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 is provided with a glass tube heater (indirect heating means) arranged below the evaporator and a pipe heater (direct heating means) arranged in contact with the evaporator for defrosting the evaporator. ing. Then, a sensor (detection means) for detecting the temperature of the upper, lower, left, right, and center of the evaporator is attached, and on/off control and output of the glass tube heater and the pipe heater are controlled based on the detection signal from the sensor. Is going.

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

JP-A-2000-121233

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

Therefore, it is an object of the present invention to provide a refrigerator having a simple configuration, capable of efficiently performing a defrosting operation for removing frost formation on an evaporator and reducing power consumption.

In order to achieve the above-mentioned object, the present invention is a refrigerator that cools the inside with cooled air, wherein a compressor that is connected to an evaporator and drives a refrigeration cycle, and an air flow inside the evaporator. A blower that generates cooled air by generating the air, a freezer compartment that is maintained at a temperature at which the cooled air can store and freeze an article, and a first device that can measure the temperature of air flowing in the evaporator. It has a temperature measurement part, a heating device which heats the evaporator, and a control part which acquires the first measured temperature from the first temperature measurement part, and the control part is acquired from the first temperature measurement part. A refrigerator that stops the compressor and starts a defrosting operation that drives the heating device when a first measured temperature becomes lower than a first threshold value that is lower than a lower limit temperature for maintaining the freezer compartment. it can.

According to this structure, the temperature of the air flowing through the evaporator is measured by the first temperature measurement unit. Then, in the first temperature measurement unit, when the amount of frost formed on the evaporator is large and clogging occurs, the first temperature measurement unit is affected by the frost temperature (measures the frost temperature). Since there is a difference between the temperature of the air flowing through the evaporator and the temperature of the 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 frosted state of the evaporator without using a special device for detecting the frosted amount. is there. Further, since the frosted state can be acquired accurately, 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 suppress energy consumption to a low level.

In the above configuration, the evaporator has a refrigerant pipe through which a low-temperature refrigerant flows, and a fin arranged in contact with the refrigerant pipe, and the first temperature measurement unit includes the refrigerant pipe and It may be arranged apart from the fins. In the evaporator, the low-temperature refrigerant flows inside the refrigerant pipe, and frost starts to form on the surface of the refrigerant pipe and/or the fins. By arranging the first temperature measurement unit away from the refrigerant pipes and fins, even if frost is formed on the refrigerant pipes and fins, the first temperature measurement unit keeps the evaporator until a certain amount of frost adheres. It is possible to measure the temperature of flowing air. That is, it is possible to determine a state in which frost is formed but no clogging occurs, and execution of the defrosting operation in a state in which no clogging is generated can be suppressed. In the refrigerator, the defrosting operation may be performed every time a certain period of time elapses. In that case, the defrosting operation is performed even if the frost formation amount is small. In addition, here, the first temperature setting portion is arranged to be “distant” from the fins, but “separated” means “thermally separated”. Therefore, those physically separated from each other and those having a thermally separated member interposed are included.

In the above configuration, the first temperature measurement unit may be attached to the refrigerant pipe via an attachment member having a lower thermal conductivity than the refrigerant pipe. According to this configuration, heat transfer between the first temperature measuring unit and the refrigerant pipe can be suppressed and it is easy to firmly fix it. As a result, the temperature measured by the first temperature measurement unit is less likely to be affected by the temperature of the refrigerant pipe when the clogging is not generated due to frost formation.

In the above configuration, a return port that returns the air that has cooled the inside to the upstream side of the evaporator is provided, and the first temperature measurement unit is arranged on the downstream side of a surface facing the return port of the evaporator. It may have been done.

In the above configuration, a second temperature measuring unit capable of measuring the temperature of the air flowing through the evaporator is further provided, and the second temperature measuring unit is located farther from the heating device than the first temperature measuring unit. When the defrosting operation is performed, the control unit is provided, and when the first measured temperature becomes higher than a predetermined third threshold value, the control unit acquires from the second temperature measurement unit. If the second measured temperature is higher than the fourth threshold lower than the third threshold, the defrosting operation is terminated, and if the second measured temperature is lower than the fourth threshold, the second measured temperature is The defrosting operation may be continued after the defrosting operation is continued until it becomes higher than the fifth threshold value which is higher than the fourth threshold value.

According to this configuration, the temperature of the air flowing at different positions of the evaporator is measured by the two temperature measurement units, and the frosting state of the evaporator is determined based on the measurement result, so that a more accurate frosting state is obtained. It is possible to obtain Then, since the defrosting operation is performed so as to correspond to the accurate frosted state, it is possible to perform the defrosting operation without excess or deficiency.

In the above configuration, the control unit stops the compressor when the first measured temperature becomes lower than the first threshold value, continues the stopped state for a predetermined standby time, and then acquires the temperature. When the difference between the first measured temperature and the first measured temperature when the compressor is stopped is less than or equal to 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 is generated based on the temperature measured by the first temperature measurement unit, the temperature is a factor different from frost (an increase in outside air temperature, It may occur when storing hot items, opening and closing doors, etc. By providing the standby time, it is possible to eliminate the determination that the eye is clogged due to a factor other than the eye clog, and suppress unnecessary defrosting operation.

In the above configuration, the control unit may drive the blower during the standby time.

According to the present invention, it is possible to provide a refrigerator having a simple configuration, capable of efficiently performing defrosting operation for removing frost formation on an evaporator, and reducing 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 an evaporator in the state where the 1st temperature sensor was attached to the curve part of a pipe. It is an enlarged view of an evaporator in the state where the 1st temperature sensor was attached to the straight part of a pipe. It is a figure which shows the 1st temperature sensor in the state which has not frosted. It is a figure which shows the 1st temperature sensor in the state which has partially frosted. It is a figure which shows the 1st temperature sensor in the state which the clogging has arisen by frost formation. It is a flow chart showing the defrosting operation of the refrigerator concerning the present invention. It is a flow chart showing the defrosting operation of the refrigerator concerning the present invention. It is a block diagram of another example of the refrigerator concerning the present invention. It is the schematic of the evaporator with which the refrigerator concerning this invention was equipped. It is a flowchart which shows the procedure which performs a defrosting operation in 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-back direction, the up-down direction, the left-right direction, and the like may be shown, but in this case, the state shown in FIG. 1 is used as a reference. 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). As described below. 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 which is open on the front side and is surrounded by a wall body filled with a foam heat insulating material. The heat insulating box body 100 is provided with a partition shelf 101 that divides the inside into upper and lower parts. A machine room 102 is provided on the rear side of the lower part of the heat insulating box 100. The machine room 102 is separated from the space of the heat-insulating box 100 for storing the articles and the wall body filled with the foam heat insulating material. A part of a cooling device for cooling each storage room of the refrigerator Rf is arranged in the machine room 102. 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 foamed heat insulating material, and divides the space of the heat insulating box body 100 in which the articles are stored into upper and lower parts. Note that, here, the lower side of the partition shelf 101 is the freezing section 1 and the upper side is the refrigerating section 2. In the refrigerator Rf, the freezing section 1 is provided with a storage room that is maintained at a temperature (for example, −18° C. or lower) that can surely freeze the article. The refrigerating 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 unlikely to freeze (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 compartment 11, an upper freezing compartment 12, and an ice making compartment 13. The lower stage freezing chamber 11 and the upper stage freezing chamber 12 are storage chambers for storing stored materials in a frozen state (for example, stored 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 freezing compartment 11, the upper freezing compartment 12, and the ice making compartment 13 are one integrated heat insulating area.

As shown in FIG. 1, the lower freezing compartment 11 is provided in the lower portion 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 in the lower freezing compartment 11, and is arranged at the bottom of the lower freezing compartment 11. The first storage case 111 moves integrally with the door 114. The second storage case 112 is arranged above the first storage case 111, and the third storage case 113 is arranged 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 parts, the right side of which is the upper freezing compartment 12 and the left side is the ice making compartment 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 maker 133 is a device that freezes water supplied from a water tank (not shown) to produce ice. The ice maker 133 is arranged above the storage case 132, and the produced ice falls into the storage case 132.

As shown in FIG. 2, a rectifying plate 14 is provided on the inner side of the freezing section 1. A partition member 30 is further provided inside the straightening vane 14. A cold air duct 32 through which cold air that cools the lower freezing chamber 11, the upper freezing chamber 12, and the like flows is provided between the flow straightening plate 14 and the partition member 30. As shown in FIG. 1, the freezing compartment 1 of the heat insulating box 100 is provided with a groove extending vertically in the central portion, and the flow straightening 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 the cool air duct 32.

The gap between the partition member 30 and the wall surface on the inner side of the freezing section 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 which 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 freezing fan 33 is a blower that generates a flow of air (airflow) in the cold air flow path 3. The freezing fan 33 is arranged above the evaporator 5. By operating the freezing fan 33, an ascending airflow is generated in the evaporator chamber 31. That is, by operating the freezing fan 33, the airflow flows through the evaporator 5. In the refrigerator Rf, the freezing fan 33 operates while the cooling device is performing the cooling operation.

The cool air flow path 3 is connected to the cool air duct 32 at the upper part. The cool air generated in the evaporator chamber 31 flows into the cool air duct 32. The cold air duct 32 is an air passage for supplying cold air to the lower freezing compartment 11 and the upper freezing 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, 323 are provided at positions where cold 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, respectively. Further, the discharge port 324 is provided at a position where the discharge port 324 flows into the upper freezing chamber 12. In the refrigerator Rf, the cold air is made to flow into the ice making chamber 13 from the upper freezing chamber 12, but a discharge port for making the cold air flow into the ice making chamber 13 may be provided.

The cold air that has flowed into the lower freezing chamber 11 and the upper freezing chamber 12 and has cooled the inside of the freezing compartment 1 returns to the evaporator chamber 31 via the freezing return duct 34. The freezing 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 freezing return cold air.

As shown in FIGS. 1 and 2, the refrigerating compartment 2 is provided with a refrigerating compartment 21, a chilled compartment 22, and a vegetable compartment 23 from the top. The refrigerating chamber 21 is maintained at a low temperature (for example, 3°C to 5°C) that can suppress deterioration of the article. Further, the chilled chamber 22 is lower than the refrigerating chamber 21 and is maintained at a temperature (for example, 2° C. to −1° C.) at which the article is hard to freeze. The vegetable compartment 23 is maintained at a temperature (for example, 5° C. to 8° C.) that suppresses low temperature damage of vegetables. It should be noted that these storage chambers and their maintenance temperatures are examples, and may be in the range of the temperature at which the article freezes, or may be provided with a storage chamber at a temperature different from these.

The front side of the refrigerating compartment 2 is open, and a refrigerating door 27 is provided on the front side so that it can be opened and closed. The refrigerating door 27 is pivotally supported by the heat insulation box 100 and rotates around a support shaft to open and close the opening of the refrigerating compartment 2. The refrigerating door 27 may be one that can close the opening of the refrigerating compartment 2 with one member (door), or may be one that can be closed with two or more members (door). .. Here, it is a refrigerating door 27 that can close the opening of the refrigerating compartment 2 with one sheet.

In the refrigerator Rf, by opening the refrigerating door 27, articles can be stored in the refrigerating compartment 21, the chilled compartment 22 and the vegetable compartment 23, or the stored articles can be taken out. Inside the refrigerating door 27, there is provided a door pocket 271 for standing and storing bottles, cans, paper packs and the like.

The refrigerating room 21 is provided with a movable shelf 24 that can divide the space into upper and lower parts. 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 refrigerating chamber 21. The movable shelf 24 can change its position in the refrigerating chamber 21 in the height direction. By changing the position of the movable shelf 24, a wide variety 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 insulation box 100 is attached to the lowest stage of the refrigerating chamber 21.

Further, a fixed shelf 26 fixed to the inner wall of the heat insulating box 100 is attached below the fixed shelf 25 at a constant interval. A portion sandwiched between the fixed shelves 25 and the fixed shelves 26 is the tilt chamber 22, and a portion sandwiched between the fixed shelves 26 and the partition shelf 101 is the vegetable compartment 23. The chilled chamber 22 includes a storage case 221. The storage case 221 is provided so as 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. A packing is provided on at least one of the inner surface of the front door portion 222 or the chilled chamber 22. When the storage case 221 is stored in the back, the front door part 222 closes the opening on the front surface of the chilled chamber 22. Further, the chilled chamber 22 has a restricted air flow, and has a temperature different from that of the refrigerating chamber 21.

The vegetable compartment 23 also has the same configuration as the chilled compartment 22, and includes a storage case 231 and a front door 232. Unlike the chilled chamber 22, the vegetable chamber 23 has a gap that allows air to flow in. Thereby, the cold air which has cooled the refrigerating chamber 21 and the chilled chamber 22 described later can be made to flow into the vegetable chamber 23. A return opening 441 of a refrigeration return duct 44, which will be 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 straightening vane 28 is provided inside the refrigerating compartment 2. A cold air duct 4 through which cold air for cooling the cold storage compartment 21, the chilled compartment 22 and the vegetable compartment 23 flows is provided between the straightening vane 28 and the wall surface on the back side of the cold storage compartment 2. As shown in FIG. 1, the refrigerating compartment 2 of the heat insulating box 100 is provided with a groove extending vertically in the central portion, and the straightening vane 28 covers the front surface of the groove. The gap between the current plate 28 and the groove serves as the cool 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 needed to adjust the inflow of cold air from the cold air flow path 3. The refrigerating fan 42 is a blower for pushing away the cool air that has flown in by opening the damper 41. The operation of the refrigeration fan 42 causes the cool air to rise in the cool air duct 4. The discharge port 43 is a through hole provided in the current plate 28. The refrigerator Rf is provided with five discharge ports 43, but the number is not limited to this, and may be more or less. It may be provided at least at a position where cold air flows into the refrigerating chamber 21 and the chilled chamber 22.

The cold air flowing through the cold air duct 4 flows into the refrigerating chamber 21 and the chilled chamber 22 via the discharge port 43. The vegetable compartment 23 has a higher storage temperature than the refrigerating compartment 21 and the chilled compartment 22. Therefore, the vegetable compartment 23 is cooled by inflowing the cold air that has been heated in the refrigerator compartment 21 and the chilled compartment 22 to remove heat from the articles. The cold air that has cooled the vegetable compartment 23 flows through the refrigeration return duct 44, returns to the cold air passage 3, and is guided to the evaporator chamber 31 in which the evaporator 5 is provided. The cold air that has cooled the refrigerating compartment 2 and has flowed into the refrigerating return duct 44 may be referred to as refrigerating 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 refrigeration return duct 44 includes a return opening 441 and a return opening 442. Like the cold air duct 4, the refrigeration return duct 44 is formed in a space sandwiched between the groove and the flow regulating plate 28. The return opening 441 is a through hole that penetrates the current plate 28. The refrigerated cold air that has flowed in from the return opening 441 flows downward in the refrigerated return duct 44. Then, as shown in FIG. 1, from the lower right side of the evaporator 5, it returns to the evaporator chamber 31 of the cool air flow path 3.

In the cooling device for the refrigerator Rf according to the present invention, one evaporator 5 cools all the storage chambers. The cold air passage 3 and the cold air duct 4 are communicated with each other through the through hole 103 of the partition shelf 101, and the opening and closing of the damper 41 adjusts the inflow amount of the cool air generated in the cold air passage 3 into the cold air duct 4. Has been done. 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 freezing compartment 1. Further, when the damper 41 is opened and the cooling device is operating, the cold air circulates in both the freezing compartment 1 and the refrigerating compartment 2. That is, the damper 41 is opened only when the refrigerating compartment 21, the chilled compartment 22 and the vegetable compartment 23 are cooled.

The cooling device of the refrigerator Rf will be described. The cooling device uses a refrigeration cycle. The refrigerating apparatus has a configuration in which a compressor Comp, a condenser (not shown), an expander (not shown), and an evaporator 5 are connected by pipes (not shown), and the inside thereof is filled with a refrigerant. There is. In a refrigeration system, a compressor compresses a refrigerant and a condenser condenses it. The condensed refrigerant is expanded by the expander and then evaporated by the evaporator 5. Then, the heat of vaporization due to the evaporation of the refrigerant removes heat from the air flowing around the evaporator 5, thereby generating cold air. Since the cooling device uses a well-known technique, its details are 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 has an inflow part and an outflow part into which the refrigerant flows. The pipe 51 meanders to the left and right toward the bottom, folds back at the lower end in a direction intersecting the meandering direction (the depth direction of the paper surface in FIG. 4), and again meanders to the left and right.

The fin 52 is a flat plate. A plurality of fins 52 are provided and arranged in parallel in the lateral direction. The pipe 51 penetrates the fin 52, and the pipe 51 and the fin 52 are connected. The pipes 51 and the fins 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 the storage chambers of the refrigerator Rf. When the returned cool air is referred to as return cool air, the return cool air receives heat from the articles and the air inside each storage room of the refrigerator Rf. Therefore, the temperature of the return cold air is higher than that when it is generated in the evaporator chamber 31. Then, the returned cool air is cooled again when flowing upward in the evaporator 5, and is sent to each storage chamber as cold air.

The return cold air may evaporate food and dew attached to the inside of the storage when heat is taken from the articles and air in each storage room to raise the temperature. Therefore, the returned cool air may contain more water vapor than the cool air generated in the evaporator 5. When such return cold air is cooled again in the evaporator 5, the water vapor contained in excess of the saturated water vapor amount is condensed in the pipes 51 and the fins 52. As described above, the evaporator 5 generates cold air that can cool the lower freezing chamber 11 and the upper freezing chamber 12, and the temperatures of the lower freezing chamber 11 and the upper freezing chamber 12 are lower than the melting point (0° C.) of water. .. Therefore, the water condensed on the pipes 51 and the fins 52 is solidified and adheres as frost.

Then, when the time during which the operation is continuously performed becomes long, the amount of frost attached increases and the frost causes clogging of the fins 52. If the fins 52 are clogged, it becomes difficult for air to flow through the evaporator 5, and the cooling efficiency is reduced. Therefore, in the refrigerator Rf, the defrosting operation of heating the evaporator 5 to melt the frost is performed. In the refrigerator Rf, in order to secure a stable cooling capacity for a long period of time, a defrosting operation is performed at regular intervals, that is, periodically. 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 refrigerating fan 42, the freezing 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 section Cont. Further, the storage unit Mem and the clock 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 storage unit Mem has a configuration including a semiconductor memory such as a ROM or a RAM. In addition to these, a portable memory such as a flash memory or a hard disk may be used. Further, the control program may be stored in the storage unit Mem, and a necessary control program may be activated as needed to perform control.

The clock unit CL is a circuit that measures time. The clock 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 clock unit CL and can acquire the measured time information.

The control unit 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 ice melts to melt the frost attached to the evaporator 5. Therefore, the control unit Cont stops the compressor Comp during the defrosting operation to suppress 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 refrigerating fan 42 and the freezing fan 33 and closes the damper 41. This limits the inflow of warmed air into each storage chamber and suppresses the temperature rise in each storage chamber.

Next, the configuration required 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 air flowing through the evaporator 5, and a glass tube heater 7 (heating device that heats the evaporator 5 during the defrosting operation) ) And. A freezing fan 33 is provided above the evaporator 5, and since air is sucked up by the freezing fan 33 in the evaporator 5, the air flows upward from below. Therefore, the return port 442 of the refrigerating return duct 44 is opened below the evaporator 5.

Further, the glass tube heater 7 is arranged below the evaporator 5. The glass tube heater 7 heats the surrounding air and the evaporator 5 with radiant heat when an electric current is applied. When the frost attached to the evaporator 5 is melted by the defrosting operation, water drops downward. If the water directly adheres to the glass tube heater 7, it may cause failure or damage. Therefore, a heater cover for avoiding water is provided above the glass tube heater 7. In addition, below the glass tube heater 7, a defrost water receiver 53 for receiving water generated during the defrost operation is provided. The defrost water is collected by the defrost water receiver 53 and then flows into an evaporation tray (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 return cool air is directly blown to the first temperature sensor 61, it is difficult to measure the accurate temperature of the air flowing through the evaporator 5 due to the influence of the temperature of the return cool air. Therefore, it is preferable that the first temperature sensor 61 is located at a position where the return cold air is not directly blown, that is, at a position that does not face the return port 442 in the outflow direction of the return cool air from the return port 442 of the refrigeration return duct 44. Furthermore, it is more preferable that the first temperature sensor 61 is located at a position that does not directly face the return port 442 of the refrigeration return duct 44.

Further, in the present embodiment, the first temperature sensor 61 detects the amount of frost formed on the evaporator 5 as described later. The return port 442 of the refrigerating return duct 44 opens below the evaporator 5 and flows in the evaporator 5 from the lower side to the upper side. Therefore, the water vapor exceeding the saturated water content contained in the return cool air is in the lower part of the evaporator 5. First, the pipes 51 and the fins 52 are aggregated into frost. Therefore, since the evaporator 5 sequentially frosts from the bottom, when frost is detected at the top of the evaporator 5, the amount of frost at the bottom of the evaporator 5 is such that the cooling capacity of the evaporator 5 is hindered. May be.

Therefore, in the present embodiment, it is preferable that the first temperature sensor 61 is located below the evaporator 5 and at a position that does not face the return port 442 of the refrigeration return duct 44. In FIG. 4, the temperature of the air flowing at a position (for example, an intermediate portion) that is displaced upward (downstream) from the lower end of the evaporator 5 (upstream end in the air flow 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 is exerted. There is a case to receive. Therefore, it is often difficult to accurately measure the temperature of the air flowing through the evaporator 5 at the lower end of the evaporator 5. From this also, it is preferable that the first temperature sensor 61 is arranged at a position displaced 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 in the portion between the curved portions at both ends of the pipe 51 that is provided in a meandering manner. As shown in FIG. 5A, the first temperature sensor 61 is arranged inside the curved portion of the pipe 51. Although the 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 have a lower temperature than the air flowing inside the evaporator 5. Then, in order to accurately measure the temperature of the air flowing through the inside of the evaporator 5, the first temperature sensor 61 is preferably arranged apart from the pipe 51 and the fin 52.

As shown in FIG. 5A, the first temperature sensor 61 is arranged, that is, fixed, inside the curved portion of the pipe 51 via a spacer 63. The spacer 63 is formed of a material having a low thermal conductivity such as resin or ceramic. Further, in the first temperature sensor 61, the measuring unit for measuring the temperature is fixed in a state where it 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 directly contact the air flowing inside the evaporator 5. By fixing in this way, when measuring the temperature of the air flowing through the inside of the evaporator 5, the temperature of the pipes 51 and the fins 52 is unlikely to be affected and the accurate temperature of the air can be measured. Is. The distance between the first temperature sensor 61 and the pipe 51 and the fin 52 can be, for example, about 5 mm, but 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 at the portion where the first temperature sensor 61 is attached is removed. The present invention is not limited to this, and in the case of the first temperature sensor 61 having a size that can be arranged in the gap between the fins 52, the fin 52 need not be removed. When the first temperature sensor 61, which is larger than the gap between the fins 52, is attached, it is possible to reduce the processing of the fin 52 by attaching it to the curved portion.

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

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

For example, if the door is fully opened for a long time, or if an article having a high temperature or water is apt to evaporate is stored, the return cold air contains more water than during normal operation. Then, when the return cool air having a large amount of water is cooled while flowing through the evaporator 5, the water contained in the return cool air adheres as frost on the surface of the evaporator 5. Due to the adhesion of frost, the fins 52 are blocked, and it becomes difficult for air to flow between the fins 52, and the cooling efficiency is reduced. Therefore, in the refrigerator Rf, the control unit Cont also performs the defrosting operation based on the first measured temperature from the first temperature sensor 61, in addition to the defrosting operation that is regularly performed.

The state of the first temperature sensor 61 arranged in the evaporator 5 will be described with reference to the drawings, and then the defrosting operation based on the first measured temperature from the first temperature sensor 61 will be described. FIG. 6A is a diagram showing the first temperature sensor in a non-frosting state, FIG. 6B is a diagram showing the first temperature sensor in a partially frosting state, and FIG. 6C is a block diagram due to frosting. It is a figure which shows the 1st temperature sensor in the state where is occurring.

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

As shown in FIG. 6A, when there is no frost on the pipe 51 and the fin 52, the pipe 51 and the fin 52 and the first temperature sensor 61 are sufficiently separated from each other. Since the spacer 63 has 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, the first measurement temperature (H1) measured by the first temperature sensor 61 is the temperature of the cool air flowing through the evaporator 5, that is, the temperature t2.

As shown in FIG. 6B, when frost is formed on a part of the pipe 51 and the fin 52, the pipe 51 and the fin 52 are sufficiently separated from the first temperature sensor 61. However, the distance from the surface of the attached frost to the first temperature sensor 61 is short. It can be considered that the temperature of the surface of the frost is substantially the same as the temperature of the pipe 61 and the fin 52, and the first measured temperature H1 measured by the first temperature sensor 61 is slightly lower than the temperature t2 of the cool air flowing through the evaporator 5. Become. When the amount of frost increases, the distance from the first temperature sensor 61 for frost to the surface of frost becomes shorter. As a result, the first measurement temperature H1 becomes lower as the frost formation amount increases.

Then, as shown in FIG. 6C, when the frost is formed to the extent that the clogging of the evaporator 5 occurs, 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. Further, even if air flows, the first temperature sensor 61 is covered with frost, so that it does not come into contact with the flowing air. Then, as described above, since the frost has substantially the same temperature as the pipe 51 and the fins 52, when the clogging of the evaporator 5 occurs, the first measured temperature H1 measured by the first temperature sensor 61 is It is the same as or substantially the same as the temperature t3.

In this way, by mounting the first temperature sensor 61 away from the pipe 51 and the fin 52, the first measured temperature H1 measured by the first temperature sensor 61 changes depending on the amount of frost formation. Based on the change in the first measured temperature H1, the control unit Cont determines that clogging due to frost formation on the evaporator 5 has occurred, and in addition to the regular defrosting operation, the defrosting operation is also performed. I do.

Hereinafter, details of the defrosting operation of the refrigerator Rf according to the present invention will be described with reference to the drawings. FIG. 7 is a flowchart showing the defrosting operation of the refrigerator according to the present invention.

The control unit Cont acquires the first measurement 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 control unit Cont confirms whether the first measured temperature H1 is lower than the first threshold value Th1 (step S102). In the refrigerator Rf, the temperature maintained in the lower freezing compartment 11 and the upper freezing compartment 12 can be adjusted within a certain range. Then, the temperature of the cold air flowing through the evaporator 5, that is, the first measurement temperature H1 is set by setting the temperature of the pipes 51 and the fins 52 of the evaporator 5 to be lower than the lower limit values of the lower freezing chamber 11 and the upper freezing chamber 12. However, the lower limit values of the lower freezing chamber 11 and the upper freezing chamber 12 are less than or equal to the lower limit values, and the lower freezing chamber 11 and the upper freezing chamber 12 can be cooled to the lower limit values.

As described above, when the amount of frost on the evaporator 5 is small, the air flowing in the evaporator 5 is sufficiently flowing, and the amount of frost near the first temperature sensor 61 is also small. The temperature H1 is the temperature of the air flowing in the evaporator 5. When the lower freezing chamber 11 and the upper freezing chamber 12 have the lower limit values, the evaporator 5 does not cool any more, so the temperature of the air flowing in the evaporator 5 becomes the lower limit value of the lower freezing chamber 11 and the upper freezing chamber 12. The temperature is close.

On the other hand, when the amount of frost formed on the evaporator 5 is large, as described above, the first measured temperature H1 is the same or substantially the same value as the pipe 51 and the fin 52 of the evaporator 5. Therefore, the first threshold Th1 is set to a value lower than the lower limit values of the lower freezing compartment 11 and the upper freezing compartment 12. The lower limit of the lower freezing compartment 11 and the upper freezing 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 that is lower than the lower limit values of the lower freezing compartment 11 and the upper freezing compartment 12 by a predetermined temperature. When the temperatures of the lower stage freezing chamber 11 and the upper stage freezing chamber 12 are 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 stage freezing chamber 11 and the upper stage freezing chamber 12. However, 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 temperature of the pipes 51 and the fins 52 of the evaporator 5 during the cooling operation, whereby the entire first temperature sensor 61 is defrosted before it is covered with frost. be able to. In the case of the above example (t1=-18°C, t3=-25°C), the first threshold value Th1 may be, for example, -21°C, but is not limited thereto.

When the first measured temperature H1 is higher than the first threshold value Th1 (No in step S102), the control unit Cont confirms whether or not a predetermined time has passed since the end of the previous defrosting operation (step S103). In addition, step S103 is a step of performing a periodic 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 value Th1 (Yes in step S102), the control unit Cont determines that the evaporator 5 is clogged with frost and performs the defrosting operation. Start. In addition, when a certain time has passed since the end of the previous defrosting operation (Yes in step S103), the defrosting operation is similarly started. If Yes in step S102 or Yes in step S103, the control unit Cont stops the compressor Comp (step S104). If the compressor Comp has already stopped, this step is omitted.

After stopping the compressor Comp, the control unit Cont energizes the glass tube heater 7 to start the 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 control unit Cont stops the refrigeration fan 42 and the freezing fan 33 and closes the damper 41.

The control unit Cont regularly acquires the first measured temperature H1 from the first temperature sensor 61 (step S106). Then, the control unit Cont confirms whether or not the first measured temperature H1 is higher than the second threshold value Th2 (step S107). When the first measured temperature H1 is lower than the second threshold Th2 (No in step S107), the control unit Cont determines that frost remains on the evaporator 5, and determines the first measured temperature H1 and the third threshold H3. The comparison with Th3 (that is, step S106 to step S107) is repeated to continue the defrosting operation. When 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 on the evaporator 5 has melted and stops the glass tube heater 7 ( Step S108) is performed, and then the normal operation is resumed.

The second threshold Th2 is a threshold for confirming that the frost adhering to the evaporator 5 has melted. Then, as shown in FIG. 1, FIG. 2, etc., the glass tube heater 7 is arranged below the evaporator 5 at a distance. Therefore, in the evaporator 5, the frost attached to the lower portion melts. Since frost starts to melt at 0° C., if the first measured temperature H1 exceeds 0° C., it can be seen that the frost attached to the periphery of the first temperature sensor 61 has melted. Since the first temperature sensor 61 is provided at an intermediate portion in the vertical direction of the evaporator 5, if the entire evaporator 5 is clogged with frost before defrosting, the first measured temperature H1 is 0°C. Even if it exceeds, the upper part of the evaporator 5 may be blocked by frost. Therefore, the second threshold Th2 can be set to a temperature (for example, 10° C.) higher than the temperature at which frost melts. The second threshold value Th2 varies depending on the size of the evaporator 5 and the mounting position of the first temperature sensor 61. For example, the measured value of the first temperature sensor 61 when it is confirmed that all the frost has melted after defrosting the glass tube heater 7 after frosting the entire surface of the evaporator 5 is set as the second threshold Th2. Good.

With such a configuration, one first temperature sensor 61 can detect not only the melting of the frost that has frosted on the evaporator, but also the frosted state of the evaporator, so that it is possible to perform the regular periodical operation. In addition to the regular defrosting operation, even if the eyes are clogged due to sudden frost formation, or the frost remaining that cannot be sufficiently removed by the regular defrosting operation grows and the evaporator 5 is clogged. , Can perform defrost quickly. As a result, it is possible to suppress the decrease in the cooling capacity due to the clogging of the evaporator 5, reduce the energy consumption (electric power) of the refrigerator Rf while suppressing the decrease in the ability to store the article at low temperature, and save energy. ..

Further, even when the periodic defrosting operation is performed, it is determined whether defrosting is completed based on the first measured temperature H1 measured by the first temperature sensor 61, so there is no excess or deficiency. 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. The configuration of the refrigerator Rf of the present embodiment is the same as the refrigerator Rf of the first embodiment. Therefore, in the present embodiment, the components used in the refrigerator Rf will be described using the reference numerals used in the first embodiment.

In the refrigerator Rf, the control unit Cont controls the capacity of the cooling device, that is, the rotation speed of the compressor Comp, based on the temperature of at least one of the lower freezing compartment 11 and the upper freezing compartment 12. For example, when the set temperature (maintained temperature) of the lower stage freezer compartment 11 is set low, cold air at a temperature lower than that at the normal set temperature is required. Therefore, the control unit Cont increases the rotation speed of the compressor Comp and improves the cooling capacity of the cooling device. Then, when the rotation 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 measured temperature H1 is set to the first threshold Th1 so as not to fall below the first threshold Th1. It is set. However, there are cases where rapid cooling of the lower freezing compartment 11 is required when storing high-temperature articles, when storing a large number of articles, when starting operation of the refrigerator, and the like. In such a case, the control unit Cont may perform a transient operation in which the compressor Comp is rotated at a high rotation speed. In such a case, the first measured temperature H1 may fall below the first threshold Th1 even if frost formation (such as that shown in FIG. 6C) that causes clogging in the evaporator 5 does not occur.

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

The control unit Cont obtains the first measured temperature H1 measured by the first temperature sensor 61, and checks whether 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 value Th1 (No in step S102), the control unit Cont confirms whether or not a certain time has elapsed since the end of the previous defrosting operation (step S103). In addition, step S103 is a step of performing a periodic 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. In addition, when a certain time has elapsed (Yes in step S103), the control unit Cont stops the compressor Comp to perform the defrosting operation (step S205). If the compressor Comp has already stopped, this step is omitted.

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 by frost 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 value Th1 may be a temporary case due to rapid cooling of the cooling device when clogging occurs due to frost formation. When the frost is formed and the eyes are clogged, the frost cannot be thawed even if the compressor Comp is stopped, so the temperature measured by the first temperature sensor 61 does not change much. 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 rises significantly. The control unit Cont uses this fact to determine whether or not the evaporator 5 is frosted. That is, after stopping the compressor Comp (step S104), the control unit Cont waits in a state in which the compressor Comp is stopped until a certain time (standby time T1) elapses (step S201). The waiting time T1 for stopping the compressor Comp may be several tens of seconds to several minutes. Here, 1 minute can be mentioned as the waiting time T1.

When a certain 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 the difference D1 from the first measured temperature H1 acquired immediately before the compressor Comp is stopped (acquired in step S101) 03 (step S2) 03. The control unit Cont checks whether the difference D1 is smaller than the difference threshold Df1 (step S204). As described above, when the temperature decreases due to frost, the temperature measured by the first temperature sensor 61 does not change much even if the compressor Comp is stopped, that is, the difference D1 is small. Therefore, when the difference D1 is smaller than the difference threshold 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. After that, the operation is the same as the flowchart shown in FIG.

If the difference D1 is larger than the difference threshold Df1 (No in step S204), the control unit Cont does not perform the defrosting operation and returns to the normal operation.

As described above, when the measured temperature acquired from the first temperature sensor 61 is lower than the preset set temperature and no frost is formed, it is possible to perform control without performing the defrosting operation. .. Accordingly, it is possible to suppress unnecessary defrosting operation and suppress wasteful energy consumption (energy saving).

Note that, during normal operation, the control unit Cont performs control to stop the freezing fan 33, but the freezing fan 33 may continue to be driven during the standby time T1. By continuing to drive the refrigeration fan 33 in this manner, a large amount of air can be caused to flow through the evaporator 5 only when the temperature is temporarily lowered and no clogging occurs, and the comparative measurement temperature can be obtained. It can help raise H11. Further, when clogging occurs due to frost formation, air does not easily flow inside the evaporator 5, so that even if the refrigeration fan 33 is driven, the comparative measurement temperature H11 is unlikely to be affected.

The features other than these are the same as those 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 shown in FIGS. 9 and 10 includes a second temperature sensor 62 in addition to the first temperature sensor 61 as a temperature measuring unit that measures the temperature of the air flowing through the evaporator 5. The other parts have the same configuration as the refrigerator Rf shown in the first embodiment, and the substantially 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 bottom of the evaporator 5 and transferred to the top during the defrosting operation. Therefore, when the defrosting operation is performed, the lower portion of the evaporator 5 is likely to have a higher temperature than the upper portion.

The eye clogging caused by frost on the evaporator 5 varies depending on the environment (temperature, humidity) of the place where the refrigerator is installed, the stored items, the opening/closing frequency, and the like. For example, frost may adhere to the whole of the evaporator 5, or it may adhere unevenly 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 part of the evaporator 5. That is, in the case of performing the defrosting operation, it can be said that the condition is more severe when frost is attached to the entire evaporator 5 than when it is attached to a part.

Generally, in a refrigerator, it is often set to perform defrosting operation on the assumption that the conditions are severe, and like the first and second embodiments, it flows through the middle portion of the evaporator 5. When the end of the defrosting operation is determined by the temperature of the air, the second threshold Th2 that determines the end of the defrosting is set high. When the termination of the defrosting operation is determined only by the first temperature sensor 61, when the second threshold value Th2 is the most severe condition, that is, when the glass tube heater 7 melts all the frost attached to the entire evaporator 5. The temperature is set to be the same as or higher than the temperature measured by the first temperature sensor 61.

As described above, in the evaporator 5, frost does not always adhere to the whole when the defrosting operation starts. For example, frost may be unevenly distributed on the upper and lower parts of the evaporator 5, that is, the amount of frost may be smaller than when frost is attached to the whole. In order to cope with such a case, the refrigerator Rf1 of the present embodiment is provided with the 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 in a place where frost is hardly melted during the defrosting operation is measured, and the temperature of the air flowing due to the change in temperature or the temperature of the pipe 51 or the fin 52 due to the adhesion of frost is measured. Determine whether you are measuring Therefore, the second temperature sensor 62 has a structure in which the frost does not easily melt during defrosting, that is, in the vicinity of the place where the frost remains until the end, that is, in the place far from the glass tube heater 7 (here, the upper portion 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 the spacer 63 similar to the first temperature sensor 61. However, the configuration is not limited to this, and the first temperature sensor 61 may be attached to the evaporator 5 by a different method. As the attachment of the second temperature sensor 62, it is possible to widely adopt a method in which the second temperature sensor 62 can be stably placed in a state of being separated from the pipe 51 and the fin 52 by a certain distance (for example, 5 mm) or more. In the present embodiment, the second temperature sensor 62 is arranged near the accumulator 53 for temporarily storing the refrigerant that has flowed inside the evaporator 5.

Then, in the refrigerator Rf1 according to the present embodiment, the control unit Cont starts the defrosting operation on the basis of the first measured temperature H1 measured by the first temperature sensor 61, and the first measured temperature H1 and the second measured temperature H1. The defrosting operation is stopped based on the temperature measured by the temperature sensor 62 (here, the second measured temperature H2).

That is, after confirming that the first temperature sensor 61 has defrosted the lower portion of the evaporator 5 than the middle portion, the second temperature sensor 62 confirms that the upper portion of the evaporator 5 has been defrosted. By doing so, excessive defrosting operation can be suppressed. The procedure of the defrosting operation utilizing 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 portion of the evaporator 5 based on the second measured temperature H2 between steps S107 and S108 of the flowchart shown in FIG. It is composed. Therefore, in the following description, a part different from the flowchart of FIG. 7 will be mainly described. In step S107, the third threshold Th3 is used instead of the second threshold.

In the flowchart shown in FIG. 11, steps S101 to S106 and step S108 are common. That is, the control unit Cont starts the defrosting operation when the first measured temperature H1 becomes lower than the first threshold value Th1. Then, the control unit Cont regularly acquires the first measured temperature H1 even during the defrosting operation.

Then, the control unit Cont confirms whether or not the first measured temperature H1 is higher than the third threshold value 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 while the entire evaporator 5 is frosted. That is, in the defrosting operation, the threshold value is set on the assumption that the frosted state of the evaporator 5 is the severest. When frost adheres only to a part of the evaporator 5, the frost may be melted in the entire evaporator 5 before the first measured temperature H1 reaches the second threshold value Th2. In consideration of such defrosting when only a part is frosted, the third threshold value Th3 is a looser condition in the defrosting operation than the second threshold value Th2, that is, a low temperature (for example, 5). ℃) is set.

When the first measured temperature H1 is lower than the third threshold value Th3 (No in step S107), the control unit Cont determines that frost remains on the evaporator 5, and determines the first measured temperature H1 and the third threshold value H3. 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 value 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 in the upper portion of the evaporator 5. Like the first temperature sensor 61, the second temperature sensor 62 causes clogging due to frost formation as compared with when the air is flowing. The second measurement temperature H2 decreases when the temperature is high. Therefore, the control unit Cont confirms whether 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 to determine whether the air is flowing near the second temperature sensor 62, that is, the upper part of the evaporator 5, or whether the air is blocked. Is the step. Therefore, the fourth threshold Th4 can be set to a temperature (for example, 1° C.) at which it can be seen that frost has melted.

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

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

In the comparison between the second measured temperature H2 and the fifth threshold value Th5 (step S304), the defrosting operation is performed to some extent, but it is determined that the upper part of the evaporator 5 has a clogging due to frost formation. These are the steps performed in. Since the frost remains after the defrosting operation is performed to some extent, it is considered that the amount of frost is large or the frost is unevenly distributed in part. When such frost is generated, even if it is confirmed that the frost around the second temperature sensor 62 has melted from the second measured temperature H2, it is far from the glass tube heater 7 and the second temperature sensor 62 is also present. It is conceivable that frost may remain in the part far from. Therefore, the control unit Cont sets the fifth threshold Th5 to a stricter condition than the fourth threshold Th4, that is, a higher temperature (for example, 8° C.) 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 on the evaporator 5, and determines the second measured temperature H2 and the fifth threshold. 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 value Th5 (Yes in step S304), the control unit Cont determines that the frost of the evaporator 5 has melted and turns on the glass tube heater 7. It stops (step S108) and returns 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 configured to determine the end of frost. As a result, the frosted state of the evaporator 5 can be more accurately grasped, and defrosting is performed based on the accurate frosted state, so it is possible to perform the defrosting operation without excess or deficiency.

The other features are the same as those of the first embodiment.

In the present embodiment, if the defrosting operation is not ended after comparing the second measured temperature H2 and the fourth threshold value Th4, the fifth condition that is more severe than the fourth threshold value Th4 during the defrosting operation. It is a threshold. However, the present invention is not limited to this. For example, when it is possible to determine that the surrounding frost has been removed to some extent by comparing the second measured temperature H2 and the fourth threshold Th4, instead of the fifth threshold Th5, the fourth threshold Th4 is used. May be used. In this case, in the flowchart shown in FIG. 11, the configuration is the same as the operation of returning to Step S301 after No in Step S302.

In the refrigerator according to the present invention described above, the temperature measuring unit (the first temperature sensor 61 or the second temperature sensor 62) flows inside the evaporator 5, not the evaporator 5 (the pipe 51, the fin 52) itself. It is provided to measure the temperature of air. When the amount of frost formed on the evaporator 5 increases, the temperature measuring unit measures the frost temperature. In this way, an accurate frosting amount is acquired by utilizing the difference in the measured temperature by the temperature measuring unit depending on the frosting state (frosting amount). Therefore, it is not necessary to provide a detection unit for detecting the amount of frost by image processing or weight. Further, since the frosted state can be determined based on the measured temperature that is easy to measure and has a small amount of information, the process can be simplified.

Although the embodiment of the present invention has been described above, the present invention is not limited to this content. The embodiments of the present invention can be modified in various ways without departing from the spirit of the invention.

Rf Refrigerator 100 Insulation box 101 Partition shelf 102 Machine room 103 Through hole Comp Compressor 1 Freezer compartment 2 Refrigerator compartment 11 Lower freezer compartment 111 First storage case 112 Second storage case 113 Third storage case 114 Door 12 Upper freezer compartment 121 Door 122 Storage case 13 Ice making room 131 Door 132 Storage case 133 Ice making machine 14 Rectifier plate 21 Refrigerating room 22 Chilled room 221 Storage case 222 Front door part 23 Vegetable room 231 Storage case 232 Front door 24 Movable shelf 25, 26 Fixed shelf 27 Cold storage Door 271 Door pocket 28 Straightening plate 3 Cold air flow path 30 Partition member 31 Cold air generation part 32 Cold air duct 321, 322, 323, 324 Discharge port 33 Freezing fan 34 Freezing 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 Evaporator 51 Pipe 52 Fin 61 First temperature sensor 62 Second temperature sensor 7 Glass tube heater 71 Heater cover Cont Control section Mem Storage section CL Clock section

Claims (5)

A compressor connected to the evaporator to drive the refrigeration cycle;
An air blower that generates cooled air by generating a flow of air inside the evaporator,
A freezer compartment that is maintained at a temperature at which the cooled air can store the article in a frozen state,
A first temperature measuring unit capable of measuring the temperature of air flowing in the evaporator;
A heating device for heating the evaporator,
A refrigerator having a control unit that acquires a first measured temperature from the first temperature measurement unit,
When the first measured temperature acquired from the first temperature measuring unit becomes lower than a first threshold value lower than a lower limit temperature for maintaining the freezer compartment, the control unit stops the compressor and You can start the defrosting operation that drives the heating device ,
When the first measured temperature becomes lower than the first threshold value, the control unit stops the compressor, continues the stopped state for a predetermined standby time, and then acquires the first measured temperature. A refrigerator that drives the heating device to start the defrosting operation when the difference between the first measured temperature when the compressor is stopped and the first measured temperature is equal to or less than a predetermined difference value . The refrigerator according to claim 1 , wherein the control unit drives the blower during the standby time. A compressor connected to the evaporator to drive the refrigeration cycle;
An air blower that generates cooled air by generating a flow of air inside the evaporator,
A freezer compartment that is maintained at a temperature at which the cooled air can store the article in a frozen state,
A first temperature measuring unit capable of measuring the temperature of air flowing in the evaporator;
A second temperature measuring unit capable of measuring the temperature of air flowing in the evaporator;
A heating device for heating the evaporator,
A refrigerator having a control unit that acquires a first measured temperature from the first temperature measuring unit and a second measured temperature from the second temperature measuring unit ,
When the first measured temperature acquired from the first temperature measuring unit becomes lower than a first threshold value lower than a lower limit temperature for maintaining the freezer compartment, the control unit stops the compressor and Start the defrosting operation that drives the heating device ,
The second temperature measurement unit is provided at a position farther than the first temperature measurement unit when viewed from the heating device,
The said control part WHEREIN: When the said 1st measured temperature becomes higher than the 3rd threshold value determined beforehand, when the said defrosting operation is performed, the said 2nd measured temperature is higher than the said 3rd threshold value. When the second measured temperature is lower than the fourth threshold, the defrosting operation is terminated when the temperature is higher than the fourth lower threshold, and the second measured temperature is higher than the fifth threshold higher than the fourth threshold when the second measured temperature is lower than the fourth threshold. Refrigerator that ends after defrosting operation continues until it gets higher . The evaporator has a refrigerant pipe in which a low-temperature refrigerant flows inside, and a fin arranged in contact with the refrigerant pipe,
The refrigerator according to any one of claims 1 to 3, wherein the first temperature measurement unit is arranged so as to be thermally separated from the refrigerant pipe and the fin. A return port for returning the air that has cooled the inside to the upstream side of the evaporator;
The said 1st temperature measurement part is a refrigerator in any one of Claim 1 to 4 arrange|positioned rather than the surface which opposes the said return port of the said evaporator.

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