JPH08136092A - Freezer - Google Patents

Abstract

PURPOSE: To provide a defrosting control device for a freezer capable of judging an accurate amount of frosting in order to perform always a proper defrosting operation. CONSTITUTION: This freezer comprises an air blowing means 6 for feeding air cooled with an evaporator into a cooling chamber; a defrosting means 9 for removing frost generated at the evaporator; an evaporator temperature sensing means 1 for use in sensing a temperature in the evaporator; a frosting amount judging means 7 for judging an amount of frost in reference to either a temperature of the evaporator or its increasing gradient detected by the evaporator temperature sensing means 1 after operating the air blowing means 6 during a stopped state of freezing cycle; and a defrosting control means 8 for operating the defrosting means 9 in the case that an amount of frost detected by a frost amount judging means 7 is more than its predetermined value. With such an arrangement as above, it is possible to reduce a thermal resistance between a surface of frost and air to make a more realized state of thermal insulating and heat accumulating effects of frost, so that an accurate amount of frosting may always be judged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defrosting control device for a refrigerating device such as a refrigerator / freezer or an air conditioner.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication (Kokai) No. 3-31668 discloses an example of a defrost control device in a conventional refrigeration system. Japanese Patent Application Laid-Open No. 3-31668 stores the evaporation temperature after a predetermined time from the start of operation (corresponding to the evaporator temperature during the refrigeration cycle operation), that is, a specific temperature at a time when the amount of frost is relatively small. The defrosting signal is output on the assumption that a predetermined amount of frost is formed when the difference from the current evaporation temperature reaches a predetermined value based on the temperature.

[0003]

However, in the conventional method, the property that the evaporation temperature during the refrigeration cycle changes depending on whether there is a lot of frost or not is applied, but the evaporation temperature has a lot of frost. Since it is almost determined by the refrigerating capacity of the refrigerating cycle, it is not practically effective when considering the influence of variations in the temperature detecting means and fluctuation factors of the refrigerating capacity.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a defrosting control device for a refrigeration system, which can accurately determine the amount of frost formation in order to always perform proper defrosting. .

[0005]

To achieve this object, the refrigerating apparatus of the present invention comprises a refrigerating cycle in which a compressor, a condenser, a throttle device, and an evaporator are sequentially connected, and cooling is performed by the evaporator. Blower means for sending air to the cooling chamber, defrosting means for removing frost generated in the evaporator, evaporator temperature detecting means for detecting the temperature of the evaporator, and the blower means during the refrigeration cycle stop Frost amount determining means for determining the amount of frost by the evaporator temperature detected by the evaporator temperature detecting means or the increasing gradient thereof, and the defrosting means when the frost amount by the frost amount determining means is a predetermined value or more. And defrosting control means for operating.

The cooling chamber temperature detecting means for detecting the temperature of the cooling chamber, the cooling chamber temperature control means for stopping the operation of the refrigerating cycle in order to keep the cooling chamber temperature at the set value, and the cooling chamber temperature control means. While the refrigeration cycle is stopped, the blower is operated to determine the amount of frost based on the evaporator temperature or its increase gradient, and the defrosting unit that operates when the amount of frost by the frost amount determination unit is equal to or greater than a predetermined value. And a frost control means.

A first timer for repeatedly counting a first predetermined time, a second timer for counting a second predetermined time, and a freezing for a predetermined time of the second timer after a lapse of a predetermined time by the first timer. Refrigeration cycle stop control means for stopping the cycle, frost amount determination means for operating the blower means while the refrigeration cycle is stopped by the refrigeration cycle stop control means, and determining the frost amount by the evaporator temperature or its increasing gradient, and the frost amount And a defrosting control unit that operates the defrosting unit when the amount of frost by the determining unit is equal to or larger than a predetermined value.

Further, a cooling chamber temperature detecting means for detecting the temperature of the cooling chamber, a cooling chamber temperature control means for stopping the operation of the refrigerating cycle to keep the cooling chamber temperature at a set value, and a timer for counting a predetermined time. The frost amount determining means for determining the frost amount by the evaporator temperature or the increasing gradient of the evaporator temperature by operating the blower means while the refrigerating cycle is stopped by the cooling chamber temperature control means after the elapse of a predetermined time by the timer, and the frost amount determining means. And a defrost control means for operating the defrost means when the amount of frost is equal to or more than a predetermined value.

Further, cooling chamber temperature detecting means for detecting the temperature of the cooling chamber, cooling chamber temperature control means for stopping the refrigeration cycle to keep the cooling chamber temperature at a set value, and a timer for repeatedly counting a predetermined time. A frost amount determining unit that determines the frost amount based on the evaporator temperature or an increasing gradient of the evaporator temperature by operating the blower unit while the refrigeration cycle is stopped by the cooling chamber temperature control unit after the elapse of a predetermined time by the timer. Defrost control means for operating the defrosting means when the amount of frost by the predetermined value or more, and a predetermined time changing means for making the predetermined time of the timer after defrosting or after the start of operation longer than the predetermined time thereafter. It is characterized by being configured.

[0010]

According to the present invention, the temperature of the evaporator when the refrigeration cycle is stopped is determined by the heat insulation / heat storage effect of frost and the heat transfer environment around the evaporator regardless of the refrigerating capacity, and by further operating the blowing means. The heat resistance between the frost surface and the air is reduced to make the heat insulation and heat storage effect of frost more visible.

Further, the amount of frost formation is judged while suppressing an unnecessary temperature rise by operating the blowing means while the refrigeration cycle is stopped by the cooling chamber temperature control means.

Further, the refrigeration cycle is stopped for the second predetermined time period at every first predetermined time period and the air blowing means is operated to determine the amount of frost formation while suppressing an unnecessary temperature rise.

Further, after a lapse of a predetermined time after the start of the operation or the end of the defrosting operation, the blowing means is operated while the refrigeration cycle is stopped by the cooling chamber temperature control means to determine the amount of frost formation while suppressing an unnecessary temperature rise.

Further, after the elapse of a predetermined time after the start of operation or the end of the defrosting operation, the air blowing means is operated while the refrigeration cycle is stopped by the cooling chamber temperature control means, and thereafter, after a predetermined time shorter than the first predetermined time elapses. By operating the air blower while the refrigeration cycle is stopped by the cooling chamber temperature controller, the amount of frost formation is determined while suppressing unnecessary temperature rise.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of the refrigerator-freezer of this embodiment. In FIG. 1, 1 is evaporator temperature detection means for detecting the temperature of the evaporator, 2 is suction temperature detection means for detecting the intake air temperature of the evaporator, and 3 is a cooling chamber temperature for detecting the temperature of the freezing compartment of the refrigerator / freezer. It is a detection means. Reference numeral 4 is a cooling chamber temperature control means for simultaneously stopping the operation (ON / OFF) of the compressor 5 and the blowing means 6 in order to keep the temperature of the freezing room at a set value.

Denoted at 7 is a frost amount determining means for operating the blower means 6 while the compressor is stopped by the cooling chamber temperature control means 4 so that the rate of change in the temperature difference between the suction temperature and the evaporator temperature is below a predetermined value. For example, it is determined that there is frost above a predetermined value, and defrosting of the evaporator is started by the defrosting means 9 via the defrosting control means 8.

FIG. 2 is a schematic diagram of a refrigerating system of a refrigerator-freezer. 5 is a compressor, 10 is a condenser cooled by outside air, 11 is a capillary tube which is a throttle device, 1
Reference numeral 2 denotes an evaporator that cools the air in the refrigerator, and these are sequentially connected to form a refrigeration cycle 13.

A blower 6 blows air cooled by the evaporator 12 into the cooling chamber. Defrosting means 9 removes the frost formed on the evaporator 12, and is composed of, for example, an electric heater. Reference numeral 1 is an evaporator temperature detecting means having a temperature sensor 1a for detecting the temperature of the evaporator 12, and 2 is suction air temperature detecting means having a temperature sensor 2a for detecting the temperature of intake air to the evaporator 12. Further, the arrows in the figure represent the flow of the refrigerant.

FIG. 3 is a thermal circuit schematically showing the heat transfer environment around the evaporator 12. The principle of the present invention will be briefly described with reference to FIG. In FIG. 3, 14 is the heat capacity of frost adhering to the evaporator 12, 15 is the heat capacity of the evaporator itself, 16 is the heat resistance between the evaporator and frost, 17 is the heat resistance of the frost itself, and 18 is between the frost and surface air. Is the thermal resistance of. It is considered that the frost-air heat resistance 18 is almost constant regardless of the amount of frost formed, and since it is large as a heat resistance, it is adiabatic by frost from the temperature difference between the air temperature Vb around the evaporator and the evaporator temperature Va.・ To analyze the heat storage effect and determine the amount of frost, frost-air heat resistance 1
The temperature difference between 8 is large, and the heat insulation due to frost and the temperature difference of the stored heat are small.

Therefore, the blower means 6 is operated to promote the heat transfer between the frost and the surface air by the air flow to reduce the frost-air heat resistance 18, thereby increasing the heat insulation due to the frost and the difference in temperature of the stored heat. be able to. Further, by detecting the evaporator temperature while the compressor is stopped, the evaporator temperature is almost determined by the heat insulation and heat storage effect of frost without being affected by the refrigerating capacity, which is advantageous for determining the amount of frost formation. .

Next, actual characteristics based on the above principle will be shown and described with reference to FIGS. 4 and 5. FIG. 4 is a characteristic graph showing the difference in change characteristics of the temperature difference between the air temperature Vb and the evaporator temperature Va due to the operation stop of the air blowing means 6 while the compressor is stopped, and the vertical axis indicates the difference between the air temperature Vb and the evaporator temperature Va. Temperature and the horizontal axis represent time. I and II are change characteristics when the amount of frost is large, where I is the blower stop and II is the blower operation. In addition, III and IV are change characteristics when the amount of frost is small, III is a blower stop, and IV is a blower operation. The time T0 to T1 is during the compressor operation period, and there is a difference of Va-Vb between when the amount of frost is large and when the amount of frost is small, only V0-V1. Considering the variation, it cannot be said that the temperature difference is effective enough to determine the amount of frost formation.

The period between T1 and T2 (= Ta) is a unit time during the compressor stop period, and since Va is not influenced by the refrigerating capacity during this period, Va-Vb decreases according to a certain time constant. As a result, the difference between the decreasing gradients when the amount of frost is large and when the blowing means 6 is operating is larger than the difference between the decreasing gradients when the blowing means 6 is stopped.

That is, the blowing means 6 is more than the difference ((V1-V4)-(V0-V2)) in the decreasing gradient per unit time when the amount of frost is small and when the amount of frost is large when the blowing means 6 is stopped.
The difference ((V1-V5)-(V0-V3)) in the decrease gradient between when the frost formation amount is small and when the frost formation amount is large is larger.

FIG. 5 is a graph showing the change in the decreasing gradient ((Va-Vb) / Ta) per unit time with respect to the amount of frost formation. The solid line shows the operation of the blower and the dotted line shows the stop of the blower. Vset on the vertical axis is a predetermined value of the decreasing gradient, and corresponds to a predetermined value Dset of the frost formation amount to be defrosted. In the case of the air blower operation, the change in the decrease gradient is large and good with respect to the frost formation amount over the entire area, while on the other hand, when the air blower is stopped, the change in the decrease gradient is small with respect to the frost formation amount. The resolution for determining the amount of frost is degraded, and the determination accuracy is degraded.

An example of the operation of the refrigerator having the above-mentioned structure will be briefly described with reference to the drawings. FIG. 6 is a timing chart showing an operation example of the present embodiment, in which the horizontal axis represents time, the vertical axis represents changes in the temperature of the cooling chamber, the operation of the compressor 5 and the blower 6, and the operation of the frost amount determiner 7. The frost amount determination result and the operation of the defrosting means 9 are shown.

The frost amount determining means 7 operates the blower means 6 for a unit time (T
a) Operate only for minutes, and determine the amount of frost formation by the above method. This operation is performed every time the compressor is stopped, and when the amount of frost is equal to or greater than the predetermined value (at the time of A0), the defrosting means 9 performs defrosting. After the defrosting is completed, the above operation is repeated again.

As described above, according to this embodiment, the evaporator 1
Evaporator temperature detecting means 1 for detecting the temperature (Va) of 2;
Suction temperature detecting means 2 for detecting the intake air temperature (Vb) to the evaporator 12, cooling chamber temperature detecting means 3 for detecting the temperature of the cooling chamber, and a compressor 5 for keeping the cooling chamber temperature at a set value. Frost amount by the cooling chamber temperature control means 4 for stopping the operation of the compressor and the decreasing gradient per unit time of the differential temperature between the suction temperature and the evaporator temperature by operating the blower means 6 while the compressor is stopped by the cooling chamber temperature control means 4. Frost amount determining means 7 for determining
When the frost amount determined by the frost amount determination means is equal to or greater than a predetermined value, the defrosting means 9
Since the cooling chamber temperature is below the set value and the blower unit 6 is operated while the compressor is stopped, the thermal resistance between the frost surface and the air is reduced. As a result, the heat insulation / heat storage effect of frost can be made more apparent, and the amount of frost formation can be accurately determined.

A second embodiment of the present invention will be described below with reference to the drawings. FIG. 7 is a block diagram of the refrigerator / freezer of the second embodiment. In FIG. 7, 19 is a first timer that repeatedly counts a first predetermined time, and 20 is a second timer that counts a second predetermined time (a unit time for detecting the decreasing gradient of the temperature difference between the suction temperature and the evaporator temperature). 2 timers. Reference numeral 21 is a refrigeration cycle stop control means for stopping the compressor for a predetermined time of the second timer 20 after a predetermined time by the first timer 19, and 22 is a refrigeration cycle stop control means 21 for controlling the blower means 6 while the compressor is stopped. It is a frost amount determination means that operates and determines the frost amount based on the decreasing gradient per unit time. Hereinafter, the same components as those in FIG. 1 are designated by the same reference numerals and detailed description thereof will be omitted.

An example of the operation of the refrigerator having the above-mentioned structure will be briefly described with reference to the drawings. FIG. 8 is a timing chart showing an operation example of the present embodiment, in which the horizontal axis represents time, the vertical axis represents changes in the temperature of the cooling chamber, the operations of the first timer 19 and the second timer 20, the compressor 5 and the blowing means. 6, the operation of the frost amount determination means 22, the frost amount determination result, and the operation of the defrost means 9.

At times B0, B1 and B2 at which the first timer 19 finishes counting the predetermined time, the refrigeration cycle stop control means 21 causes the second timer 2 to operate the compressor 5.
The unit is stopped for a unit time which is a predetermined time of 0 (however, it is already stopped by the cooling chamber temperature control means 4 at the time of B1).

During this time, the frost amount determining means 7 is operated by the blowing means 6
Is operated for a unit time (Ta), and the amount of frost formation is determined by the above method.

Then, at the time of B3, it is determined that the frost formation amount is equal to or more than a predetermined value, and the defrosting means 9 defrosts. After the defrosting is completed (B4), the first timer 19 is reset and the above operation is repeated again.

As described above, according to the present embodiment, the first timer 19 for repeatedly counting the first predetermined time, the second timer 20 for counting the unit time, and the first timer 19 after the predetermined time has elapsed (2) The refrigeration cycle stop control means 21 for stopping the compressor 5 for a unit time by the timer 20 and the blower means 6 operated by the refrigeration cycle stop control means 21 while the compressor is stopped to control the temperature difference between the suction temperature and the evaporator temperature. The frost amount determining unit 22 determines the frost amount based on the decreasing gradient per unit time, and the defrosting control unit 8 operates the defrosting unit 9 when the frost amount determined by the frost amount determining unit 22 is a predetermined value or more. Therefore, the compressor 5 is stopped every predetermined time, and the blower 6 is operated for a unit time to determine the amount of frost, thereby making the heat insulation and heat storage effect of frost more apparent. It is possible to more accurately determine the amount of frost formation, and avoid the frequent determination of the amount of frost formation by performing the amount of frost formation at regular time intervals, eliminating the need for a cooling chamber by operating the air blower while the compressor is stopped. The temperature rise can be kept low.

A third embodiment of the present invention will be described below with reference to the drawings. FIG. 9 is a block diagram of the refrigerator / freezer of the third embodiment. In FIG. 9, reference numeral 23 is a timer for counting a predetermined time, and 24 is the cooling chamber temperature control means 4 after the predetermined time elapses by the timer 23, and the blower means 6 is operated for a unit time while the compressor is stopped to operate the suction temperature and the evaporator. It is a frost amount determination means for determining the frost amount based on the decreasing gradient of the temperature difference from the temperature per unit time. Hereinafter, components having the same configuration as in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted.

An operation example of the refrigerator-refrigerator having the above configuration will be briefly described with reference to the drawings. FIG. 10 is a timing chart showing an operation example of this embodiment, in which the horizontal axis represents time, the vertical axis represents changes in the temperature of the cooling chamber, the operation of the timer 23, and the compressor 5.
And the operation of the air blower 6, the operation of the frost amount determiner 24, the result of the frost amount determination, and the operation of the defroster 9.

The timer 23 finishes counting the predetermined time at the time C0, and after the time C0, the cooling chamber temperature control means 4 stops the compressor 5 (C1 and C).
In 2), the blower 6 is operated for a unit time and the amount of frost formation is determined. Then, at the time of C2, it is determined that the frost formation amount is equal to or larger than the predetermined value, and the defrosting means 9 defrosts. After defrosting (C3
At the time point), the timer 23 is reset and the above operation is repeated again.

As described above, according to this embodiment, the cooling chamber temperature control means 4 for stopping the operation of the compressor 5 in order to keep the cooling chamber temperature at the set value, the timer 23 for counting a predetermined time, and the timer After the elapse of a predetermined time by 23, the cooling chamber temperature control means 4 operates the blower means 6 while the compressor is stopped to determine the frost amount by the decrease gradient of the temperature difference between the suction temperature and the evaporator temperature per unit time. The defrosting control unit 8 operates the defrosting unit 9 when the frost amount determined by the frost amount determining unit 24 is equal to or more than the predetermined value. Therefore, the defrosting control unit 8 operates for a predetermined time after the start of operation or the end of defrosting. After the end of the counting, the cooling chamber temperature control means 4 operates the blower means 6 for a unit time while the compressor is stopped to determine the amount of frost, thereby making the heat insulation and heat storage effect of frost more apparent. This The accurate determination of the amount of frost formation can be performed by performing the frost formation amount determination after a certain period of time from the start of operation or the end of defrosting to avoid frequent frost formation amount determination, and the air flow while the compressor is stopped Unnecessary temperature rise in the cooling chamber due to the operation of the means can be suppressed to a low level.

A fourth embodiment of the present invention will be described below with reference to the drawings. FIG. 11 is a block diagram of the refrigerator / freezer according to the fourth embodiment. In FIG. 11, 25 is a timer for counting a predetermined time, and 26 is a predetermined time changing means for making the predetermined time of the timer 25 after defrosting or after the start of operation longer than the predetermined time thereafter. Reference numeral 27 is a cooling chamber temperature control means 4 after a predetermined time has passed by the timer 25.
Thus, the frost amount determination means determines the amount of frost by operating the blower unit 6 for a unit time while the compressor is stopped to determine the frost amount based on the decreasing gradient of the temperature difference between the suction temperature and the evaporator temperature per unit time. Hereinafter, components having the same configuration as in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted.

An example of the operation of the refrigerator having the above-mentioned structure will be briefly described with reference to the drawings. FIG. 12 is a timing chart showing an operation example of this embodiment, in which the horizontal axis represents time, the vertical axis represents changes in the temperature of the cooling chamber, the operation of the timer 25, and the compressor 5.
And the operation of the blowing means 6, the operation of the frost amount determination means 27, the frost amount determination result, and the operation of the defrosting means 9.

Since the counting of the predetermined time after the defrosting or the start of the operation by the timer 25 ends at the time of D0, the unit of the unit at the time of D1 when the compressor 5 is stopped by the cooling chamber temperature control means 4 after this time. The blower 6 is operated for a time period to determine the amount of frost formation.

Thereafter, the short predetermined time changed by the predetermined time changing means 26 is counted by the timer 25, and after the counting end time (D2, D3), the cooling chamber temperature control means 4 is started.
Thus, the blower 6 is operated for a unit time at the time when the compressor 5 is stopped (D2, D4), and the amount of frost formation is determined. Then, at the time of D5, it is determined that the frost formation amount is equal to or larger than the predetermined value, and the defrosting unit 9 defrosts. After the defrosting is completed (at the time of D6), the timer 25 is reset and the predetermined time is changed to a long time,
The above operation is repeated again.

As described above, according to this embodiment, the cooling chamber temperature control means 4 for stopping the operation of the compressor 5 in order to keep the cooling chamber temperature at the set value, the timer 25 for repeatedly counting the predetermined time, The frost amount for determining the frost amount by the decreasing gradient per unit time of the temperature difference between the suction temperature and the evaporator temperature by operating the blower means 6 while the compressor is stopped by the cooling chamber temperature control means 4 after the elapse of a predetermined time by the timer 25. Judgment means 2
7 and the predetermined time changing means 26 for making the predetermined time of the timer 25 after defrosting or after the start of operation longer than the predetermined time thereafter. After the time is counted, the cooling chamber temperature control unit 4 operates the blower unit 6 for a unit time while the compressor is stopped to determine the amount of frost, thereby making the heat insulation and heat storage effect of frost more apparent. By doing so, it is possible to accurately determine the frost formation amount, and frequently by performing the frost formation amount determination after a predetermined time shorter than the predetermined time from the start of operation or defrosting until the first frost formation amount determination is performed. It is possible to suppress the unnecessary temperature rise of the cooling chamber due to the operation of the blower while the compressor is stopped, while avoiding the determination of the frost formation amount.

In this embodiment, the criterion for determining the amount of frost is the decreasing gradient of the temperature difference between the suction temperature and the evaporator temperature per unit time. A similar effect is obtained with an increasing gradient or evaporator temperature at any given time. Further, the same effect can be obtained as a method of detecting a time constant of change instead of a simple temperature gradient.

[0045]

As described above, the refrigerating apparatus of the present invention sends the refrigerating cycle in which the compressor, the condenser, the expansion device and the evaporator are sequentially connected, and the air cooled by the evaporator to the cooling chamber. Blower means, defrosting means for removing frost generated in the evaporator, evaporator temperature detecting means for detecting the temperature of the evaporator, and the evaporator temperature by operating the blower means while the refrigeration cycle is stopped. Frost amount determination means for determining the frost amount by the evaporator temperature detected by the detection means or its increase gradient,
Since the defrosting control means that operates the defrosting means when the amount of frost by the frost amount determining means is equal to or greater than a predetermined value is provided, the thermal resistance between the frost surface and the air is reduced, and frost insulation
There is an effect that the heat storage effect can be made more prominent and the amount of frost formation can always be accurately determined.

The cooling chamber temperature detecting means for detecting the temperature of the cooling chamber, the cooling chamber temperature control means for stopping the operation of the refrigerating cycle in order to keep the cooling chamber temperature at the set value, and the cooling chamber temperature control means. While the refrigeration cycle is stopped, the blower is operated to determine the amount of frost based on the evaporator temperature or its increase gradient, and the defrosting unit that operates when the amount of frost by the frost amount determination unit is equal to or greater than a predetermined value. Since it is characterized by being configured with frost control means,
The thermal resistance between the frost surface and the air can be reduced to make the heat insulation and heat storage effect of frost more visible, and the frost formation amount can always be determined accurately, and frequent frost formation determinations are avoided. Therefore, there is an effect that an unnecessary temperature rise in the cooling chamber due to the operation of the blowing means while the compressor is stopped can be suppressed to a low level.

Further, a first timer for repeatedly counting the first predetermined time, a second timer for counting the second predetermined time, and a freezing for a predetermined time of the second timer after a predetermined time by the first timer has elapsed. Refrigeration cycle stop control means for stopping the cycle, frost amount determination means for operating the blower means while the refrigeration cycle is stopped by the refrigeration cycle stop control means, and determining the frost amount by the evaporator temperature or its increasing gradient, and the frost amount It is characterized in that it is constituted by defrosting control means for operating the defrosting means when the amount of frost by the judging means is equal to or greater than a predetermined value. The heat insulation and heat storage effects can be made more apparent, and the amount of frost formation can always be accurately determined. Frequent frost formation determination is avoided, and the blower while the compressor is stopped There is an effect that it is possible to suppress an unnecessary increase in temperature of the cooling chamber by the driver.

Further, a cooling chamber temperature detecting means for detecting the temperature of the cooling chamber, a cooling chamber temperature control means for stopping the operation of the refrigerating cycle to keep the cooling chamber temperature at a set value, and a timer for counting a predetermined time. The frost amount determining means for determining the frost amount by the evaporator temperature or the increasing gradient of the evaporator temperature by operating the blower means while the refrigerating cycle is stopped by the cooling chamber temperature control means after the elapse of a predetermined time by the timer, and the frost amount determining means. It is characterized by comprising defrosting control means for operating the defrosting means when the amount of frost is equal to or more than a predetermined value. The effect can be made even more visible, and the amount of frost formation can always be accurately determined. Frequent determination of the amount of frost formation is avoided, and the cooling chamber is not required due to the operation of the air blower while the compressor is stopped. There is an effect that it is possible to suppress the temperature rise low.

Further, cooling chamber temperature detecting means for detecting the temperature of the cooling chamber, cooling chamber temperature control means for stopping the refrigeration cycle to keep the cooling chamber temperature at a set value, and a timer for repeatedly counting a predetermined time. A frost amount determining unit that determines the frost amount based on the evaporator temperature or an increasing gradient of the evaporator temperature by operating the blower unit while the refrigeration cycle is stopped by the cooling chamber temperature control unit after the elapse of a predetermined time by the timer. Defrost control means for operating the defrosting means when the amount of frost by the predetermined value or more, and a predetermined time changing means for making the predetermined time of the timer after defrosting or after the start of operation longer than the predetermined time thereafter. Since it is characterized by being configured, the thermal resistance between the frost surface and the air can be reduced to make the adiabatic and thermal storage effect of frost more visible, and it is always accurate. It is determined frost formation amount, frequently avoiding performing frosting quantity judgment, there is an effect that an unnecessary temperature rise of the cooling chamber by blowing means operating in the compressor stops can be kept low.

[Brief description of drawings]

FIG. 1 is a block diagram of a refrigerator-freezer according to a first embodiment of the present invention.

FIG. 2 is a schematic view of a refrigeration cycle in the same example.

FIG. 3 is a thermal circuit diagram around the evaporator in the embodiment.

FIG. 4 is a characteristic diagram of change in temperature difference between suction temperature and evaporator temperature in the example.

FIG. 5 is a characteristic diagram of the amount of frost and the temperature difference in the example.

FIG. 6 is a timing chart showing an operation example in the same embodiment.

FIG. 7 is a block diagram of a refrigerator-freezer according to a second embodiment of the present invention.

FIG. 8 is a timing chart showing an operation example in the same embodiment.

FIG. 9 is a block diagram of a refrigerator-freezer according to a third embodiment of the present invention.

FIG. 10 is a timing chart showing an operation example in the same embodiment.

FIG. 11 is a block diagram of a refrigerator-freezer according to a fourth embodiment of the present invention.

FIG. 12 is a timing chart showing an operation example in the same embodiment.

[Explanation of symbols]

 1 Evaporator Temperature Detection Means 3 Cooling Chamber Temperature Detection Means 4 Cooling Chamber Temperature Control Means 5 Compressor 6 Blower Means 7, 22, 24, 27 Frost Amount Determination Means 8 Defrost Control Means 9 Defrost Means 10 Condenser 11 Throttling Device 12 evaporator 13 refrigeration cycle 19 first timer 20 second timer 21 refrigeration cycle stop control means 23, 25 timer 26 predetermined time changing means

Claims (5)

[Claims] 1. A refrigeration cycle in which a compressor, a condenser, a throttling device, and an evaporator are sequentially connected, a blower means for sending the air cooled by the evaporator to a cooling chamber, and frost generated in the evaporator. Defrosting means for removing the temperature, evaporator temperature detecting means for detecting the temperature of the evaporator, evaporator temperature detected by the evaporator temperature detecting means by operating the blower means during the refrigeration cycle stop, or its increase A refrigeration apparatus comprising: frost amount determining means for determining a frost amount based on a gradient; and defrost control means for operating the defrosting means when the frost amount by the frost amount determining means is equal to or more than a predetermined value. 2. A cooling chamber temperature detecting means for detecting the temperature of the cooling chamber, a cooling chamber temperature control means for stopping the operation of the refrigerating cycle to keep the cooling chamber temperature at a set value, and the cooling chamber temperature control means. While the refrigeration cycle is stopped, the blower means is operated to determine the frost amount by the evaporator temperature or its increasing gradient, and the defrosting means is operated when the frost amount by the frost amount determining means is equal to or more than a predetermined value. The refrigerating apparatus according to claim 1, which is configured by frost control means. 3. A first timer that repeatedly counts a first predetermined time, a second timer that counts a second predetermined time, and a freezing time of the second timer for a predetermined time after a lapse of the predetermined time by the first timer. Refrigeration cycle stop control means for stopping the cycle, frost amount determination means for operating the blower means while the refrigeration cycle is stopped by the refrigeration cycle stop control means, and determining the frost amount by the evaporator temperature or its increasing gradient, and the frost amount The refrigeration apparatus according to claim 1, further comprising: defrost control means that operates the defrost means when the frost amount determined by the determination means is equal to or greater than a predetermined value. 4. A cooling chamber temperature detecting means for detecting the temperature of the cooling chamber, a cooling chamber temperature control means for stopping the operation of the refrigeration cycle in order to keep the cooling chamber temperature at a set value, and a timer for counting a predetermined time. The frost amount determining means for determining the frost amount by the evaporator temperature or the increasing gradient of the evaporator temperature by operating the blower means while the refrigerating cycle is stopped by the cooling chamber temperature control means after the elapse of a predetermined time by the timer, and the frost amount determining means. The refrigerating apparatus according to claim 1, which is configured by defrosting control means for operating the defrosting means when the amount of frost is equal to or more than a predetermined value. 5. A cooling chamber temperature detecting means for detecting the temperature of the cooling chamber, a cooling chamber temperature control means for stopping a refrigerating cycle to keep the cooling chamber temperature at a set value, and a timer for repeatedly counting a predetermined time. A frost amount determining means for determining a frost amount based on the increasing gradient of the evaporator temperature or the temperature of the evaporator by operating the blower means while the refrigeration cycle is stopped by the cooling chamber temperature control means after a predetermined time by the timer, and the frost amount. Defrost control means for operating the defrost means when the amount of frost by the determination means is equal to or greater than a predetermined value, and predetermined time changing means for making the predetermined time of the timer after defrosting or after the start of operation longer than the predetermined time thereafter. The refrigerating apparatus according to claim 1, which is constituted by: