JP2017166745A - refrigerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigerator having a simple structure, efficiently performing a defrosting operation for removing frost on an evaporator, and reducing power consumption. SOLUTION: When a control unit acquires a first temperature h1 measured by a first temperature measuring unit and a second temperature h2 measured by a second temperature measuring unit, and the second temperature h2 is higher than a second threshold value b2. In the first heating mode, the operation of the second heating device 8 is started, and when the first temperature h1 becomes higher than the first threshold value b1, the operation of the second heating device 8 is terminated. [Selection diagram] Fig. 6

Description

  The present invention relates to a refrigerator and relates 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 sheathed 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, center, etc. of the evaporator are attached, and on / off and output control of the glass tube heater and the sheathed heater are performed based on the detection signals from the sensors. Is going.

  Since the glass tube heater and the sheathed heater are controlled based on detection signals from temperature sensors arranged at a plurality of locations of 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, the temperature in the vicinity of the portion detected by the sensors is raised, and the evaporator is heated uniformly. Therefore, many sensors are required, the configuration is complicated, and the cost is increased. In addition, since the configuration is such that the output of a plurality of heating means is adjusted or ON / OFF is controlled based on detection signals from a plurality of sensors, the control is complicated and required for the control circuit. Ability to increase. 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 for cooling a storage room with air cooled by an evaporator, the first temperature measuring unit for measuring the temperature of the upper part of the evaporator, A second temperature measuring unit that measures the temperature of the lower part, a first heating device that is disposed below the evaporator and indirectly heats the evaporator, and is heated directly in contact with at least the upper part of the evaporator Control for acquiring the first temperature measured by the second heating device and the first temperature measuring unit and the second temperature measured by the second temperature measuring unit and controlling the operation of the first heating device and the second heating device. The controller starts the operation of the second heating device when the second temperature is higher than the second threshold, and operates the second heating device when the first temperature becomes higher than the first threshold. Control is performed in the first heating mode in which the process is terminated.

  According to this configuration, the lower part of the evaporator having a large amount of frost formation is heated by the first heating device, and the upper part having a small amount of frost formation is heated by the second heating device. And since heating of a 2nd heating apparatus is delayed after starting a heating with a 1st heating apparatus, in the 1st heating apparatus of the upper part of an evaporator, the part which is hard to heat is also heated. Thereby, the heating unevenness of an evaporator can be suppressed and reliable defrosting is possible. Moreover, compared with the case where it heats only with a 1st heating apparatus, an evaporator can be heated uniformly in a short time, and energy saving is also possible. Moreover, it is only possible to control the operation of the second heating device based on the temperature of the upper part and the lower part of the evaporator, and it is possible to heat the evaporator uniformly with simple control.

  The said structure WHEREIN: The said control part may perform control which stops a said 1st heating apparatus, when the said 2nd temperature reaches | attains the 3rd threshold value higher than a 2nd threshold value. By doing in this way, even if the evaporator is in the frosting state different from usual or different from assumption, it can suppress heating a lower part excessively. Thereby, useless power consumption can be suppressed and energy saving is possible.

  In the above configuration, the control unit may start the operation of the second heating device after the start of the operation of the first heating device in the first heating mode.

  In the above configuration, the control unit may stop the operation of the first heating device after the operation stop of the second heating device in the first heating mode.

  In the above configuration, the control unit can be controlled in a second heating mode in which the first heating device is operated and the second heating device is stopped, and the control unit calculates the frost formation amount of the evaporator by calculation. The control unit may switch between the first heating mode and the second heating mode based on the amount of frost formation. By setting it as such a structure, it is possible to perform efficient defrost operation irrespective of the frost formation state of an evaporator. Thereby, the stable energy saving effect can be acquired over a long period of 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 a flowchart showing the defrost operation of the refrigerator concerning this invention. It is a timing chart which shows operation | movement with a glass tube heater and a sheathed heater. It is a flowchart when performing a defrost operation. It is a timing chart of the modification of the timing chart shown in FIG. It is a graph which shows the relationship between the measured value of a 1st temperature sensor, the measured value of a 2nd temperature sensor, and the amount of frost formation of an evaporator. It is a flowchart of the defrost operation of the refrigerator concerning this invention.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  Next, the configuration necessary for the defrosting operation will be described. In order to perform the defrosting operation, a first temperature sensor 61 that measures the temperature of the evaporator 5, a second temperature sensor 62, a glass tube heater 7 that indirectly heats the evaporator 5 during the defrosting operation, and evaporation And a sheathed heater 8 that directly heats the vessel 5. The first temperature sensor 61 is provided on the top of the evaporator 5. The second temperature sensor 62 is provided below the evaporator 5. Note that the evaporator 5 is configured such that cold air flows back from below.

  If cold air is blown directly to the second temperature sensor 62, it is difficult to detect the exact temperature of the evaporator 5. Therefore, it is preferable that the second temperature sensor 62 measures the temperature at a position shifted from the lower end of the evaporator 5 to the upper part.

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

  Further, when the second temperature sensor 62 is provided at the lower end, the heat of the glass tube heater 7 may be directly detected, and in this case also, it is difficult to accurately measure the temperature of the evaporator 5. . From this point of view, it is preferable that the second temperature sensor 62 measures the temperature at a position shifted upward from the lower end of the evaporator 5. In the case of the lower end portion, water that has melted back cold air or frost also flows down, so that it is easily affected by these effects. Also from these things, it is better that it is not a lower end part.

  As shown in FIG. 4, a sheathed heater 8 meandering like the pipe 51 through which the refrigerant flows is attached to the evaporator 5 in contact with the fins 52. The sheathed heater 8 is provided above the position where the second temperature sensor 62 of the evaporator 5 is attached. The sheathed heater 8 arranges an electric wire inside a metal heat transfer pipe having a high thermal conductivity such as aluminum or copper, and generates Joule heat generated when an electric current is passed through the electric wire via the heat transfer pipe. This is a contact-type heating device that heats the fins 52. In the present invention, the heater has a shape in which an electric wire is arranged inside the heat transfer pipe. However, the present invention is not limited to this, and the evaporator 5 is not limited to the flow of the airflow flowing through the evaporator 5. Fins such as a heater that heats the fin 52 by inductively heating the metal plate that is in contact with and heated directly by passing an electric current through a plate-like electrode and heating the metal plate that is in contact with the fin 52 The heater of the structure which contacts 52 and heats directly can be employ | adopted widely.

  Next, the electrical configuration of the refrigerator Rf will be described. As shown in FIG. 3, in the refrigerator Rf according to the present invention, the damper 41, the refrigeration fan 42, the refrigeration fan 33, the first temperature sensor 61, the second temperature sensor 62, the glass tube heater 7, the sheathed heater 8, and the compressor Comp. Is connected to the controller Cont. In addition, a storage unit Mem and a timer unit CL are connected to the control unit Cont. The control unit Cont can always access the storage unit Mem, can store information in the storage unit Mem, and can read information from the storage unit Mem. The memory | storage part Mem has the structure containing semiconductor memories, such as ROM and RAM. In addition to these, a portable memory such as a flash memory or a hard disk may be used. Further, the control may be performed by storing a control program in the storage unit Mem and starting a necessary control program as necessary.

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

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

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

  Since refrigeration return cold air and refrigeration return cold air return from the lower part to the evaporator 5, frost adheres from the lower part to the evaporator 5. And when there is much frost amount, frost has adhered to the lower part of the evaporator 5, and when there is much frost amount, frost has also adhered to the upper part of the evaporator 5. Although the glass tube heater 7 has a large amount of heat, it is provided below the evaporator 5 and is therefore effective for heating the lower part of the evaporator 5. Since the glass tube heater 7 is heated by radiant heat, not only the lower part of the evaporator 5 but also the upper part is heated. Moreover, the sheathed heater 8 is provided in the upper part of the evaporator 5, and heats an upper part.

  Therefore, in the refrigerator Rf according to the present invention, when the frosting amount of the evaporator 5 is large, the glass tube heater 7 and the sheathed heater 8 are operated assuming that both the upper part and the lower part of the evaporator 5 are frosting. The evaporator 5 is heated in the 1 heating mode. Thereby, while being able to shorten defrost time, it can suppress that the evaporator 5 is heated more than necessary. When the amount of frost formation on the evaporator is small, the evaporator 5 is heated in the second heating mode in which only the glass tube heater 7 is operated on the assumption that frost is formed on the lower portion of the evaporator 5.

  In the refrigerator Rf according to the present invention, the control unit Cont calculates the frost formation amount of the evaporator 5 by calculation. Here, a method for calculating the amount of frost formation will be described. In the refrigerator Rf, in the refrigerator Rf, the frost formation amount of the evaporator 5 varies depending on the use state (outside temperature, door opening / closing frequency, etc.). The control part Cont uses various sensors provided in the refrigerator Rf, and uses the outside temperature, the door opening / closing frequency, the temperature of the refrigerator compartment 21, the temperature of the lower freezer compartment 11 (upper freezer compartment 12), and the compressor Comp continuously. Information such as the operating time, the measured temperature of the first temperature sensor 61, the measured temperature of the second temperature sensor 62, and the like is acquired. These pieces of information are stored in the storage unit Mem. The storage unit Mem is provided with a table for obtaining the frost formation amount of the evaporator 5 separately from the storage area of these information.

  For example, although the temperature of the refrigerator compartment 21 or the temperature of the lower freezer compartment 11 is difficult to decrease, it is determined that the amount of frost formation in the evaporator 5 is increased when the continuous operation time of the compressor Comp is increased. In the refrigerator Rf, it is possible to prepare a table in which the temperature change of the refrigerating chamber 21 or the temperature change of the lower freezing chamber 11 and the continuous operation time of the compressor Comp are prepared as parameters in the storage unit Mem. It is. Further, since the outside air temperature and the door opening / closing frequency are information related to the change in the amount of frost formation, a table including these information as parameters may be created. One table may include a large number of parameters, or a plurality of types of tables may be provided.

  The control unit Cont calls the information stored in the storage unit Mem and the table from the storage Mem, and calculates the frost formation amount of the evaporator 5 by calculation. For example, the control unit Cont acquires the temperature change (temperature change amount per unit time) of the lower freezer compartment 11 and the continuous operation time of the compressor Comp from the storage unit Mem while going back a predetermined time from the current time. . And the control part Cont calculates the amount of frost formation of the evaporator 5 with reference to a table from the temperature change of the lower freezer compartment 11, and the continuous operation time of the compressor Comp. If there is a table using other information as a parameter, the frost formation amount of the evaporator 5 is calculated based on the information.

  Next, details of the defrosting operation will be described with reference to the drawings. FIG. 5 is a flowchart showing the defrosting operation of the refrigerator according to the present invention. The control part Cont acquires information on each part of the refrigerator Rf at a predetermined interval (for example, once every several tens of seconds) while the cooling device performs the cooling operation.

  The control unit Cont confirms that the defrosting start time has come (step S101). Thereafter, the control unit Cont calculates the frost formation amount D1 of the evaporator 5 based on the information of the refrigerator Rf and the table required for calculating the frost formation amount of the evaporator 5 stored in the storage unit Mem (step). S102). The control part Cont confirms whether or not the frost formation amount D1 is larger than the threshold Th1 (step S103).

  When the amount of frost formation D1 is larger than the threshold value Th1 (Yes in step S103), the control unit Cont determines that the amount of frost formation is large and performs the first heating that operates both the glass tube heater 7 and the sheathed heater 8. The defrosting operation is started in the mode (step S104). In the first heating mode, the entire evaporator 5 is heated. Therefore, the defrosting operation is terminated when the first temperature h1 of the first temperature sensor 61 that measures the temperature of the upper portion of the evaporator 5 becomes higher than a predetermined temperature a1.

  Therefore, the control unit Cont checks whether or not the first temperature h1 measured by the first temperature sensor 61 has exceeded a predetermined temperature a1 (step S105). The controller Cont continues to heat the evaporator 5 with the glass tube heater 7 and the sheathed heater 8 until the first temperature h1 of the first temperature sensor 61 exceeds the predetermined temperature a1 (until Yes in step S105). . When the first temperature h1 of the first temperature sensor 61 exceeds the predetermined temperature a1 (Yes in step S105), the control unit Cont ends the first heating mode and ends the defrosting operation (step S106). ).

  When the amount of frost formation D1 is equal to or less than the threshold Th1 (No in step S103), the control unit Cont determines that the amount of frost formation is small, that is, the frost formation amount is mainly formed in the lower part of the evaporator 5. Thereafter, the defrosting operation is performed in the second heating mode. However, if the defrosting operation is performed only in the second heating mode, the heating (defrosting) of the upper portion of the evaporator 5 is insufficient and the frost is gradually formed. . Therefore, when the amount of frost formation D1 is equal to or less than the threshold value Th1 (No in step S103), the control unit Cont confirms whether or not all the latest three defrosting operations are heated in the second heating mode (step S107). ). When all the last three defrosting operations are in the second heating mode (Yes in step S107), the controller Cont starts the defrosting operation in the first heating mode (step S104). Thus, when defrosting in the second heating mode continues for a predetermined number of times (here, three times), the frost adhering to the evaporator 5 is effectively removed by forcibly switching to the first heating mode. It is possible. The subsequent operation is as described above, and is omitted.

  When at least one defrosting operation has not been performed in the second heating mode in the last three defrosting operations (No in step S107), the control unit Cont starts the defrosting operation in the second heating mode (step S108). In the second heating mode, the lower part of the evaporator 5 is heated. Therefore, the defrosting operation is terminated when the second temperature h2 of the second temperature sensor 62 that measures the temperature of the lower portion of the evaporator 5 becomes higher than a predetermined temperature a2.

  Therefore, the controller Cont checks whether or not the second temperature h2 measured by the second temperature sensor 62 has exceeded a predetermined temperature a2 (step S109). The controller Cont continues heating the evaporator 5 with the glass tube heater 7 until the second temperature h2 of the second temperature sensor 62 exceeds the predetermined temperature a2 (until Yes in step S109). When the second temperature h2 of the second temperature sensor 62 exceeds the predetermined temperature a2 (Yes in Step S109), the control unit Cont ends the second heating mode and ends the defrosting operation (Step S110). ).

  Although it is assumed that the first temperature sensor 61 and the second temperature sensor 62 always measure the temperature at regular intervals, the present invention is not limited to this. The control part Cont recognizes in advance the timing of the next defrosting start, and may start the measurement at a certain time before the timing of the defrosting start. For example, if the defrosting operation is performed once every 24 hours, the measurement is performed at regular intervals (for example, 30 seconds) with the first temperature sensor 61 and the second temperature sensor 62 after 23 hours have passed since the previous defrosting operation. You may make it measure the temperature h1 and h2.

  Regarding the threshold Th1, the predetermined temperature a1, and the predetermined temperature a2, the refrigerator Rf is operated under several conditions, and the frosting state on the evaporator 5 and the defrosting operation under the respective conditions are removed. It is a value determined by observing the frost state. The predetermined temperature a1 and the predetermined temperature a2 may be different temperatures or the same temperature.

  In the refrigerator according to the present invention, when the frosting amount of the evaporator 5 is large, the defrosting operation is performed in the first heating mode in which the evaporator 5 is heated by both the glass tube heater 7 and the sheathed heater 8. Thereby, compared with the case where it heats only with the glass tube heater 7, heating time can be shortened. Thereby, it can suppress that the temperature of the lower part of the evaporator 5 rises too much. From this, it is possible to reduce the load during cooling of the cooling device, and to reduce power consumption. Moreover, since defrost operation time can be shortened and the temperature rise of the evaporator 5 can be suppressed, the temperature rise of each storehouse | storage of refrigerator Rf can be suppressed. Thereby, it is possible to make the refrigerator Rf capable of saving energy for a long time without impairing reliability.

(Second Embodiment)
Another example of the refrigerator according to the present invention will be described with reference to the drawings. In the present embodiment, by adjusting the operation timing of the glass tube heater 7 and the sheathed heater 8, power consumption is suppressed and excessive temperature rise of the evaporator 5 is suppressed. The basic configuration of the refrigerator Rf is the same as that of the first embodiment. Therefore, the description about the structure of refrigerator Rf is abbreviate | omitted, and shall use what was used in 1st Embodiment about the name and code | symbol of each part.

  In the evaporator 5, the refrigeration return cold air and the refrigeration return cold air are re-cooled to generate cold air that cools each storage chamber. Since the refrigerated return air often contains moisture at a high temperature, when the evaporator 5 flows in, the contained moisture frosts on the surface of the evaporator 5. In addition, frost may be formed even with frozen return cold air. The refrigerated return cold air and the refrigerated return cold air enter the evaporator 5 from below and are cooled when rising between the fins 52. Therefore, the amount of frost formation of the evaporator 5 is larger in the lower part than in the upper part.

  Frost is the same as a solid body of water, ie ice, and requires latent heat of melting when melting from a solid to a liquid. And since there is much frosting amount of a lower part compared with an upper part, the lower part of the evaporator 5 is heated previously, and an upper part is heated after that. This heating operation will be described with reference to the drawings. FIG. 6 is a timing chart showing the operation of the glass tube heater and the sheathed heater, and FIG. 7 is a flowchart when the defrosting operation is performed.

  As shown in FIGS. 6 and 7, immediately after the start of the defrosting operation, the control unit Cont turns on the glass tube heater 7 (step S201). The heat from the glass tube heater 7 melts frost adhering to the lower part of the evaporator 5. As described above, the evaporator 5 has a lower amount of frost formation in the upper part than in the lower part. Therefore, if the glass tube heater 7 and the sheathed heater 8 are operated simultaneously, the temperature of the upper part of the evaporator 5 may be increased more than necessary, or the defrosting of the lower part may be insufficient.

  Therefore, the controller Cont determines the frosting state in the lower part of the evaporator 5 from the second temperature h2 of the second temperature sensor 62 that measures the temperature in the lower part of the evaporator 5. That is, the controller Cont checks whether or not the second temperature h2 is higher than the second threshold value b2 (step S202). When the second temperature h2 is equal to or lower than the second threshold value b2 (No in step S202), the heating with the glass tube heater 7 is continued.

  When the second temperature h2 is higher than the second threshold value b2 (Yes in step S202), the control unit Cont determines that the frost in the lower part of the evaporator 5 has melted to some extent, and starts the operation of the sheathed heater 8 ( Step S203).

  Next, the control part Cont confirms the defrosting state of the upper part of the evaporator 5 by the sheath heater 8. Therefore, the control part Cont checks whether or not the first temperature h1 measured by the first temperature sensor 61 provided on the upper portion of the evaporator 5 is larger than the first threshold value b1 (step S204). If the first temperature h1 is equal to or lower than the first threshold value b1 (No in step S204), heating by the glass tube heater 7 and the sheathed heater 8 is continued.

  When the first temperature h1 is higher than the first threshold value b1 (Yes in step S204), the controller Cont determines that the frost on the upper part of the evaporator 5 has melted to some extent, and stops the sheathed heater 8 (step S205). ). The controller Cont confirms the end time of the defrosting time, and after the end time is reached (step S206), the controller Cont turns off the glass tube heater 7 (step S207). By continuing to operate the glass tube heater 7 after the sheathed heater 8 is stopped, the ice adhering to the defrosted water receiver 53 can be melted.

  Thus, by operating the sheathed heater 8 behind the operation of the glass tube heater 7, the lower part of the evaporator 5 with a large amount of frost formation is heated first, and the upper part is heated later. Thereby, after completion | finish of defrosting, the evaporator 5 whole can be heated without excess and deficiency, and power consumption can be suppressed. Moreover, since it is possible to suppress excessive temperature rise, the load at the time of cooling of a cooling device can be reduced. This also makes it possible to reduce power consumption. In the present embodiment, by switching between the first heating mode in which the glass tube heater 7 and the sheathed heater 8 are operated and the second heating mode in which the glass tube heater 7 is operated, the power consumption is suppressed and the evaporator 5 is excessive. The temperature rise is suppressed.

(Modification)
A modification of this embodiment will be described with reference to the drawings. FIG. 8 is a timing chart of a modification of the timing chart shown in FIG. In the refrigerator Rf of the present embodiment, the sheathed heater 8 is operated after a certain time has elapsed after the glass tube heater 7 is operated. This is based on the knowledge that in the evaporator 5, the lower frost amount is larger than the upper frost amount. However, depending on the operating conditions, the bias of the frosting position may be different.

  For example, when the front surface of the evaporator 8 is frosted uniformly or almost uniformly, the temperature in the lower part of the evaporator 5 heated by the glass tube heater 7 becomes too high only by the control of the above-described flowchart. Therefore, the controller Cont monitors the second temperature h2, which is the temperature below the evaporator 5, and turns off the glass tube heater 7 when the second temperature h2 exceeds the third threshold value b3 (FIG. 8). reference). When the second temperature h2 becomes sufficiently lower than the fourth threshold value b4, the glass tube heater 7 is turned on again (see FIG. 8). Thereby, it is possible to suppress that the lower part of the evaporator 5 heats up excessively. Note that the fourth threshold value b4 when the glass tube heater 7 is turned on again is lower than the third threshold value b3.

  In addition, there may be a case where the accurate temperature cannot be detected in a special situation, for example, when only the periphery of the first temperature sensor 61 or the second temperature sensor 62 is frosted or not frosted. Also in such a case, the control part Cont operates the sheathed heater 8 after operating the glass tube heater 7 according to the timing chart as shown in FIG. 6 or FIG. About the timing of this operation start delay, the time may be delayed based on the data at the time of defrosting performed so far, or may be delayed for a predetermined time. Similarly, at the time of termination, the sheathed heater 8 is terminated before the termination of the glass tube heater 7 even if the operation of the sheathed heater 8 is not terminated under the conditions of the first temperature sensor 61 or the second temperature sensor 62. You may make it make it. The end timing of the sheathed heater 8 at this time may also be determined based on the data so far, or may be determined in advance.

(Third embodiment)
Still another example of the refrigerator according to the present invention will be described. In this embodiment, the frosting amount of the evaporator 5 is different from that of the first embodiment. The basic configuration of the refrigerator Rf is the same as that of the first embodiment. Therefore, the description about the structure of refrigerator Rf is abbreviate | omitted, and shall use what was used in 1st Embodiment about the name and code | symbol of each part.

  FIG. 9 is a graph showing the relationship between the measured value of the first temperature sensor, the measured value of the second temperature sensor, and the frost formation amount of the evaporator. FIG. 9 shows the amount of frost formation on the horizontal axis and the temperature on the vertical axis. The first temperature h1 measured by the first temperature sensor 61 is indicated by a broken line, and the second temperature h2 measured by the second temperature sensor 62 is indicated by a solid line.

  As shown in FIG. 9, both the first temperature h <b> 1 and the second temperature h <b> 2 are lower in temperature as the amount of frost formation increases. The rate of decrease is higher at the second temperature h2 than at the first temperature h1. That is, as can be seen from FIG. 9, the difference value d2 (= | h2−h1 |) between the first temperature h1 and the second temperature h2 decreases as the amount of frost formation increases.

  In the present embodiment, this is used to control the glass tube heater 7 and the sheathed heater 8 during the defrosting operation. FIG. 10 is a flowchart of the defrosting operation of the refrigerator according to the present invention. FIG. 10 shows that after the start of defrosting.

  As illustrated in FIG. 10, the control unit Cont acquires the first temperature h1 and the second temperature h2 (step S301). The controller Cont calculates a difference value d2 (= | h2−h1 |) between the first temperature h1 and the second temperature h2 (step S302).

  The control unit Cont compares the two types of first comparison value Cm1, second comparison value Cm2 (Cm1> Cm2) and the difference value d2, and determines the operations of the glass tube heater 7 and the sheathed heater 8. First, the control part Cont checks whether or not the difference value d2 is larger than the first comparison value Cm1 (step S303). When the difference value d2 is larger than the first comparison value Cm1 (Yes in step S303), the control unit Cont determines that the frosting amount of the evaporator 5 is small, and the first mode uses only the glass tube heater 7. Is selected (step S304). In addition, about the heating method of the evaporator 5, it is the same as the 2nd heating mode shown in 1st Embodiment. Therefore, details are omitted.

  When the difference value d2 is equal to or smaller than the first comparison value Cm1 (No in step S303), the control unit Cont checks whether or not the difference value d2 is larger than the second comparison value Cm2 (step S305). When the difference value d2 is larger than the second comparison value Cm2 (Yes in step S305), the control unit Cont determines that the amount of frost formation is medium. Therefore, the control part Cont operates the glass tube heater 7 and selects the second mode in which the sheathed heater 8 is operated after a lapse of time (step S306). In the second mode, the glass tube heater 7 and the sheathed heater 8 are controlled as in the operation of the second embodiment. Therefore, details are omitted.

  Further, when the difference value d2 is equal to or smaller than the second comparison value Cm2 (No in step S305), the control unit Cont has a large amount of frost attached to the evaporator 5 or an unexpected frosting state. And the third mode in which both the glass tube heater 7 and the sheathed heater 8 are operated simultaneously is selected (step S307). In the third mode, the sheathed heater 8 is operated based on the first temperature h1, and the glass tube heater 7 is operated based on the second temperature h2 (step S308).

  As described above, by controlling the operation of the glass tube heater 7 and the sheathed heater 8 based on the temperatures of the upper and lower portions of the evaporator 5, there are places where the evaporator 5 cannot be defrosted due to insufficient heating, It can suppress that the part which excessively raises the temperature of the evaporator 5 too much is made.

(Modification)
In the example shown above, the frost amount of the evaporator 5 is calculated based on the difference value d2 between the first temperature h1 and the second temperature h2, and the defrost mode is switched based on the frost amount. In this method, when the evaporator 5 is uniformly frosted, that is, when the first temperature h1 and the second temperature h2 overlap each other in the graph shown in FIG. 9, an accurate defrosting operation can be performed.

  On the other hand, the defrosting state (defrosting amount) between the upper part and the lower part may differ from the assumption depending on the operation method of the refrigerator Rf, the stored articles, and the frequency of opening and closing. For example, when the upper frost amount is large and the lower frost amount is small, the difference value d2 between the first temperature h1 and the second temperature h2 is large, but the upper frost amount is large. In order to deal with such a case, the controller Cont calculates the amount of frost formation from each of the first temperature h1 and the second temperature h2. As a calculation method, for example, a table as shown in FIG. 9 may be used.

  Thus, since the amount of frost formation is calculated from each of the 1st temperature h1 and the 2nd temperature h2, it also becomes possible to detect the partial frost formation of the evaporator 5. FIG. Thereby, the evaporator 5 can be heated without excess and deficiency, and a defrosting operation can be performed reliably.

  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.

  The refrigerator described above

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

Claims (5)

A refrigerator that cools the storage room with air cooled by an evaporator,
A first temperature measuring unit for measuring the temperature of the upper part of the evaporator;
A second temperature measuring unit for measuring the temperature of the lower part of the evaporator;
A first heating device disposed below the evaporator for indirectly heating the evaporator;
A second heating device for direct heating in contact with at least the top of the evaporator;
A controller that acquires the first temperature measured by the first temperature measurement unit and the second temperature measured by the second temperature measurement unit and controls the operation of the first heating device and the second heating device;
The controller starts the operation of the second heating device when the second temperature is higher than the second threshold, and ends the operation of the second heating device when the first temperature becomes higher than the first threshold. Refrigerator that controls in heating mode.   The refrigerator according to claim 1, wherein the control unit performs control to stop the first heating device when the second temperature reaches a third threshold value higher than a second threshold value.   The refrigerator according to claim 1 or 2, wherein when the control unit is in the first heating mode, the operation start of the second heating device is delayed from the operation start of the first heating device.   4. The control unit according to claim 1, wherein when the control unit is in the first heating mode, the operation stop of the first heating device is performed later than the operation stop of the second heating device. refrigerator. The control unit can be controlled in a second heating mode in which the first heating device is operated and the second heating device is stopped,
The control unit obtains the amount of frost formation of the evaporator by calculation,
The refrigerator according to any one of claims 1 to 4, wherein the control unit switches between the first heating mode and the second heating mode based on the amount of frost formation.

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