JPH0746018B2 - Freezer refrigerator - Google Patents

Description

TECHNICAL FIELD The present invention relates to a refrigerator / freezer in which an evaporator is heated and defrosted.

[Conventional technology]

16 and 17 show the essential parts of a conventional refrigerator-freezer disclosed in, for example, Japanese Utility Model Laid-Open No. 60-65582. This is an example of having a deflot timer. In the figure, 1 is a refrigerator box, 2 is an evaporator chamber provided in the upper back of the box 1, 3
Is an evaporator attached to the evaporator chamber 2, 4 is an end plate that supports the evaporator 3, 5 is a guide for heat convection that is attached to the lower part of the end plate 4 with its tip inward, and 6 is A glass tube heater for defrosting provided below the evaporator 3, a bulkhead 7 mounted directly above the glass tube heater 6, and 8 provided at the bottom of the evaporator chamber 2 for receiving frost and water. The toys 9 are liquid distillation tanks connected to the outlet of the evaporator 3 and arranged on the side of the evaporator 3. Reference numeral 10 denotes a blower fan provided above the evaporator chamber 2 for forcibly convection the air cooled by heat exchange with the evaporator 3 into the chamber. Reference numeral 11 denotes a defrost timer, which integrates the operation time of the compressor 12 and stops the operation of the compressor 12 at regular intervals, and also activates the glass tube heater 6 to bring the temperature of the evaporator 3 to a predetermined temperature. After that, the compressor 12 is restarted. 13 is a temperature fuse connected in series to the glass tube heater 6, and 14 is the defrost timer 11
A temperature controller, 15 is a condenser, and 16 is a decompression device connected in series to the compressor 12 via the. The evaporator 3 and the compressor 1
2. A condenser 15 and a decompression device 16 are sequentially connected by a refrigerant pipe line to form a frozen icle.

In the conventional refrigerator-freezer, the glass tube heater 6 for defrosting is provided below the evaporator 3, so that part of the air heated by the glass tube heater 6 naturally convects upward, that is, below the evaporator 3. , Part of the heated air is a guide for heat convection 5
Guided by the above, natural convection occurs on both sides of the evaporator 3.

Therefore, the frost adhering to the surface of the evaporator 3 is defrosted by heat exchange with the air that naturally convects upward, and the frost adhering to the surface of the liquid-condensing ink 9 is guided by the guide 5 for heat convection. The air that has been convected to the tank 9 is heat-exchanged and defrosted.

[Problems to be Solved by the Invention]

Since the conventional refrigerator-freezer is configured to convect the air heated by the glass tube heater 6 to the lower portion of the evaporator 3 and both side portions thereof, the heat quantity of the air heated as the distance from the glass tube heater 6 increases. The frost on the evaporator 3 is reduced, and the frost on the evaporator 3 is defrosted from the side closer to the glass tube heater 6, that is, from the bottom of the evaporator 3. Therefore, the defrosting time is relatively short in the lower part of the evaporator 3, but the upper part of the evaporator 3 and the liquid storage tank 9 become long, and the temperature inside the refrigerator is abnormally increased by the time the defrosting is completed. There was a problem.

The present invention has been made in order to solve the above problems, and an object thereof is to obtain a refrigerator-freezer capable of shortening the defrosting time.

[Means for Solving the Problems] A refrigerator-freezer according to the present invention includes a defrosting unit that is provided in a lower portion of the evaporator to heat and defrost the evaporator, and a lower temperature detecting unit that detects a refrigerant inlet temperature of the lower portion of the evaporator. An operation control means having an upper temperature detection means for detecting the refrigerant outlet temperature of the evaporator upper portion, and a compressor are provided, and while driving the defrosting means during the defrosting period, the compressor is placed in the lower portion of the evaporator. The operation is repeated when the temperature difference between the refrigerant inlet temperature and the refrigerant outlet temperature at the upper part of the evaporator becomes larger than the first value, and the operation is repeatedly stopped at the time when the temperature difference becomes smaller than the first value. It is something that is done.

Further, the defrosting means for heating and defrosting the evaporator which is located below the evaporator, the operation control means having a defrosting sensor, and the compressor are provided, and while driving the defrosting means during the defrosting period, The compressor is intermittently operated while the temperature detected by the defrost sensor rises from the melting point of frost to a predetermined temperature equal to or higher than this melting point.

[Operation] In the refrigerating refrigerator according to the present invention, the defrosting means is driven during the defrosting period, and the compressor has the first temperature difference between the refrigerant inlet temperature in the lower part of the evaporator and the refrigerant outlet temperature in the upper part of the evaporator. The operation is repeated when the temperature becomes larger than the value, and the operation is repeated when the temperature difference becomes smaller than the first value.

Further, the refrigerator-freezer according to the present invention drives the defrosting means during the defrosting period, and the temperature detected by the defrosting sensor of the compressor rises from the melting point of frost to a predetermined temperature equal to or higher than this melting point, Operate intermittently.

[Embodiment] FIG. 1 shows a first embodiment of the present invention. In the figure,
6, 9, 10, 12 to 16 show the same parts as in FIG. Reference numeral 20 denotes an evaporator which allows the refrigerant in the pipe to flow from bottom to top in FIG. Reference numeral 21 is a refrigerant moving means, which is composed of the compressor 12 and a compressor control device 22, and turns on the compressor 12 by the compressor control device 22 in accordance with the duty ratio shown in FIG.
/ OFF is controlled to move the refrigerant in the evaporator 20. Defrosting means 23 is composed of the glass tube heater 6 and a defrost timer 24. The defrost timer 24 integrates the operating time of the compressor 12 and the compressor is operated at regular intervals.
12 operation is stopped and the glass tube heater 6
After the temperature of the evaporator 20 reaches a predetermined temperature, the compressor 12 is restarted and the operation of the compressor controller 22 is stopped.

Next, the operation will be described based on the time chart shown in FIG.

When the accumulated time reaches a predetermined time, the defrost timer 24 activates the glass tube heater 6 and the compressor 12
Is stopped, and at the same time, the operation of the compressor controller 22 is started. Then, the lower portion of the evaporator 20 is heated by the air heated by the glass tube heater 6, and then the refrigerant in the pipe located at the lower portion is brought into a locally heated state.
When the compressor 12 is ON / OFF controlled by the compressor controller 22 according to the duty ratio shown in FIG. 3, the tip of the heated refrigerant is sequentially moved upward in the pipe for each operation of the compressor 12. As it moves, the heat energy of this refrigerant and the frost attached to the evaporator 20 are exchanged with each other. Therefore,
The frost attached to the evaporator 20 will be melted from below the evaporator 20.

FIG. 4 shows a second embodiment of the present invention.

This is a refrigeration cycle with evaporator 20, check valve 31, compressor 12,
This is an example configured by a condenser 15, a refrigerant control valve 32, and a pressure reducing device 16. The same parts as those in FIG. 1 are designated by the same reference numerals. In the figure, 33 is a refrigerant moving means, which is a compressor 12 and a refrigerant control valve.
32, compressor refrigerant control valve control device 34, and during normal operation, the compressor 12 is turned on and off as shown in FIG.
The refrigerant control valve 32 is opened and closed in synchronism with.

Defrosting means 35 is composed of the glass tube heater 6 and a defrost timer 36. The defrost timer 36 integrates the operation time of the compressor 12 and stops the operation of the compressor 12 at regular time intervals. After the refrigerant control valve 32 is opened by the control valve control device 34, the compressor 12 is ON / OFF controlled according to the duty ratio shown in FIG. With this construction, the working effects of this embodiment are essentially the same as those of the first embodiment.

7 and 8 show a third embodiment of the present invention.

In the figure, reference numerals 6, 9, 10, 12 to 16, 20, 23 and 24 indicate the same parts as in FIG. Reference numeral 41 is a temperature sensing element (lower temperature detecting means) such as a thermistor, which detects the lower temperature of the evaporator 20. Reference numeral 42 is a temperature sensing element (upper temperature detecting means) such as a thermistor, which detects the upper temperature of the evaporator 20. Reference numeral 43 denotes a compressor control device (operation control means) which starts the operation of the compressor 12 when the temperature difference between the lower temperature and the upper temperature becomes larger than _TH (first value), It is stopped when the difference becomes smaller than T _L (<T _H , second value). The compressor 1
2. The temperature sensing elements 41 and 42 and the compressor control device 43 constitute a refrigerant moving means.

Next, the operation will be described based on the time chart shown in FIG.

When the accumulated time reaches a predetermined time, the glass tube heater 6 is operated by the defrost timer 24 and the compressor 12
Is stopped, and at the same time, the operation of the compressor control device 43 is started. Then, the nearby air is heated by the glass tube heater 6, and the heated air rises and spontaneously convects to the lower part of the evaporator 20, so that the heated air and the pipe located at the lower part of the evaporator 20 The refrigerant in the pipe is locally heated. When locally heated in this manner, the lower temperature detected by the temperature sensing element 41 increases, and the difference between the lower temperature and the upper temperature detected by the temperature sensing element 42 increases. Then, the temperature difference exceeds T _H, restarts the operation of the compressor 12 by the compressor controller 43 to move the heated refrigerant from the bottom of the evaporator 20. When the refrigerant moves from the lower part of the evaporator 20, the unheated refrigerant moves to this lower part, so that the pipe located at the lower part is cooled, and the lower temperature detected by the temperature sensing element 41 starts decreasing. . When the temperature difference between the lower temperature and the upper temperature falls below T _L , the compressor controller 43 stops the operation of the compressor 12. When the operation of the compressor 12 is stopped, the movement of the refrigerant in the pipe is stopped, and the lower pipe and the refrigerant in the pipe are heated by the glass tube heater 6.

Hereinafter, the operation of the compressor 12, to start the temperature difference between the lower temperature and the upper temperature exceeds T _H, the operation of stopping the fall than T _L is repeated, successively, the heated coolant along the pipe Move it up. Along with the movement of the refrigerant, heat energy of the refrigerant is exchanged with the frost attached to the evaporator 20, and the frost is melted from below the evaporator 20.

FIG. 10 shows another example of the evaporator. This is the evaporator 20
Compared with, the structure of the evaporator is different. That is, in the evaporator 20, as shown in FIG. 8, the evaporating pipes are arranged in one row, and the refrigerant is made to flow from the lower side to the upper side of the evaporating tube. Then, the refrigerant is caused to flow downward from above the front row evaporation pipe, and the refrigerant that has flowed downward is made to flow upward from below the rear row evaporation pipe. Even if such an evaporator is used instead of the evaporator 20, the refrigerant flows through the rear row evaporation pipe from the lower side to the upper side, so that the same effect as that of the third embodiment can be obtained.

FIG. 11 shows a fourth embodiment of the present invention.

In the figure, 6, 9, 10, 12 to 16, 20, and 23 show the same parts as in FIG. Reference numeral 51 is a defrost sensor, which is the liquid retention tank 9
It detects the temperature of. Reference numeral 52 denotes a compressor control device (intermittent operation control means), during which the temperature detected by the defrosting sensor 51 rises from 0 ° C. (melting point of frost) to 2 ° C. to 5 ° C. (predetermined temperature above melting point of frost). The compressor 12 is operated intermittently. The compressor 12, the defrost sensor 5
1. The refrigerant control means 52 is constituted by the compressor control device 52.

While the glass tube heater 6 is driven, the defrost sensor 51
The internal pressure of the evaporator 20 is equal to or lower than the saturation pressure at which the frost melts until the temperature detected by 0 ° C reaches 0 ° C. At this time, when the compressor control device 52 is operated to operate the compressor 12, the pressure inside the evaporator 20 is lowered, and the temperature of the evaporator 20 is rather lowered. Therefore, the defrosting sensor 51 detects the defrosting sensor 51. When the temperature is 0 ° C. or lower, the compressor controller 52 is not operated.

In addition, the temperature detected by the defrost sensor 51 is 2 ° C to 5 ° C.
When the driving of the glass tube heater 6 is stopped when the temperature reaches 0 ° C., the temperature of the evaporator 20 decreases, and frost and water are attached to the surface of the evaporator 20 as ice.
The process is continued until the temperature detected by the defrost sensor 51 reaches about 10 ° C. By the time the temperature detected by the defrost sensor 51 reaches 2 ° C to 5 ° C to 10 ° C, the melted frost drops into water droplets from the evaporator 20 to the toy 8, and the frost and drainage water collected by the toy 8 is collected. Will flow out of the refrigerator.

Furthermore, the temperature detected by the defrost sensor 51 is 2 ° C to
Since the internal pressure and temperature of the evaporator 20 rise from 5 ° C to 10 ° C, if the compressor 12 is operated during this period, the pressure will decrease due to suction of the compressor, and the temperature of the evaporator 20 will decrease. Falls. Therefore, the compressor 12 is operated by the defrost sensor.
It is arranged to stop when the temperature detected by 51 reaches 2 ° C to 5 ° C.

The operation will be described based on the time chart shown in FIG.

When the accumulated time reaches a predetermined time, the glass tube heater 6 is operated by the defrost timer 24 and the compressor 12
Is stopped. Then, the air in the vicinity is heated by the glass tube heater 6, a part of the heated air naturally convects upward, that is, to the lower part of the evaporator 20, and a part of the heated air partially evaporates. Natural convection on both sides of. Therefore, the pipes located in the lower part of the evaporator 20 and the refrigerant in the pipes are locally heated by the air naturally accumulated in the lower part of the evaporator 20, and the liquid distilling tank is caused by the natural convection air on both sides of the evaporator 20. 9 is heated.

The temperature detected by the defrost sensor 51 is 0 ° C.
When it reaches (melting point of frost, point a in FIG. 13), the compressor control device 52 is operated, and the intermittent operation of the compressor 12 is started by the compressor control device 52. Then, each time the compressor 12 is operated by the compressor control device 52, the heated refrigerant in the lower part of the evaporator 20 sequentially moves upward, and with the movement of this refrigerant, the heat of the refrigerant is increased. Heat is exchanged between the energy and the frost adhering to the evaporator 20 and the liquid storage tank 9, and the frost is melted from below the evaporator 20 while the liquid storage tank 9 is being melted.
Temperature goes up.

Then, the temperature detected by the defrost sensor 51 is 2 ° C to
When it reaches 5 ° C. (point b in FIG. 13), the intermittent operation of the compressor 12 is stopped by the compressor control device 52. However, at this time, since the driving of the glass tube heater 6 is not stopped, the temperature of the liquid distillation tank 9 further rises. The temperature detected by the defrost sensor 51 is about 10 ° C (C in FIG. 13).
Point), the driving of the glass tube heater 6 is stopped,
Defrosting is complete.

FIG. 14 shows a fifth embodiment of the present invention. In the figure,
6, 9, 10, 12 to 16, 20, 32, 35 and 36 show the same parts as in Fig. 4, and 51 shows the same parts as in Fig. 11. Reference numeral 61 is a refrigerant moving means, which is composed of the compressor 12, the refrigerant control valve 32, the defrost sensor 51, and the compressor refrigerant control valve control device 62. The compressor refrigerant control valve control device 34 controls the compressor 12 and the refrigerant control valve.
The intermittent operation of 32, for example, ON / OFF control is performed according to the duty ratio shown in FIG. 15 to move the refrigerant in the evaporator 20. With this construction, the operation and effect of this embodiment are essentially the same as those of the fourth embodiment.

[Effects of the Invention] As described above, according to the present invention, the defrosting means is driven during the defrosting period, and the compressor is set to the temperature of the refrigerant inlet temperature at the lower part of the evaporator and the refrigerant outlet temperature at the upper part of the evaporator. First difference
When the temperature difference becomes larger than the value of
Since the operation is repeated by stopping when the value becomes smaller than the value of, the movement of the refrigerant in the pipe is stopped while the compressor is stopped, so the refrigerant in the evaporator lower pipe is heated by the main defrosting stage. , This heated refrigerant moves upward along the pipe due to the start of operation of the compressor, so that the temperature distribution in the evaporator is uniform, and between the refrigerant in the pipe and the frost adhering to the evaporator. Efficient heat exchange is performed, and the defrosting time can be shortened.

Further, according to the present invention, while the defrosting means is driven during the defrosting period, the compressor is intermittently operated while the temperature detected by the defrosting sensor rises from the melting point of frost to a predetermined temperature equal to or higher than this melting point. As a result, it is possible to prevent the pressure drop in the evaporator and the temperature drop in the evaporator, which would cause the compressor to operate at a temperature below the melting point of frost or above a predetermined temperature, and there is an effect that the defrosting time can be shortened.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention, FIG. 2 is a schematic view of essential parts of a refrigerator-freezer, FIG. 3 is a time chart during defrosting, and FIG. 4 is a second diagram of the present invention. FIG. 5 is a block diagram showing an embodiment, FIG. 5 is a time chart during normal operation, and FIG.
FIG. 7 is a time chart for defrosting, and FIG. 7 is a third time chart of the present invention.
Fig. 8 is a block diagram showing an embodiment of Fig. 8, Fig. 8 is a schematic view of a main part of a refrigerator-freezer, Fig. 9 is a time chart during defrosting, and Fig. 10 is a partially cutaway perspective view showing another example of an evaporator. FIG. 11 is a block diagram showing a fourth embodiment of the present invention, FIG. 12 is a schematic view of essential parts of a refrigerator-freezer, FIG. 13 is a time chart during defrosting, and FIG. 14 is a fifth embodiment of the present invention. FIG. 15 is a time chart during defrosting, FIG. 16 is a main part refrigerant circuit and electric circuit diagram of a conventional refrigerator-freezer, and FIG. 17 is a schematic view of a main part of a refrigerator-freezer. In the figure, 6 is a glass tube heater, 12 is a compressor, 20 is an evaporator, 22, 43 and 52 are compressor control devices, 24 is a defrost timer, 41 and 42 are temperature sensing elements, and 51 is a defrost sensor. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (2)

[Claims] Claim: What is claimed is: 1. A defrosting device which is located under an evaporator and which heats and defrosts the evaporator, a lower temperature detecting device which detects a refrigerant inlet temperature of the evaporator lower portion, and a refrigerant outlet temperature of the evaporator upper portion. And an operation control means having an upper temperature detection means for driving the defrosting means during the defrosting period, and the compressor is provided with a refrigerant inlet temperature at the bottom of the evaporator and the evaporation. The operation is performed when the temperature difference from the refrigerant outlet temperature of the upper part of the container becomes larger than a first value, and the operation is stopped when the temperature difference becomes smaller than a second value smaller than the first value. A refrigerator / freezer characterized by being repeatedly operated. 2. A defrosting means for heating and defrosting the evaporator under the evaporator, an operation control means having a defrosting sensor, and a compressor, and the defrosting means during the defrosting period. And the compressor is operated intermittently while the temperature detected by the defrost sensor rises from the melting point of frost to a predetermined temperature equal to or higher than this melting point.