JPS5981476A - Refrigerator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a multi-temperature refrigerator using a non-azeotropic mixed refrigerant of a high boiling point refrigerant and a low boiling point refrigerant, particularly to a low temperature freezing chamber.

Structure of a conventional example and its problems As shown in FIG. 1, a conventional multi-temperature refrigerator using a mixed refrigerant has a refrigerator main body 2 having a heat insulating material 1 separated by a partition wall 3 into a freezer compartment 4. The freezer compartment 4 is divided into a refrigerator compartment and a removable partition plate 6 to separate a low-temperature freezer compartment 4a and a general freezer compartment 4b.
The area is divided into 2 areas, and evaporators 7, 8, and 9 are provided in each area. The refrigeration cycle consists of a compressor 10 as shown in Figure 2.
, a condenser 11, a capillary 11a, a low-temperature freezer compartment eno-porator γ, a freezer compartment evaporator 8, and a refrigerator compartment borator 9 are connected in series to form a refrigeration cycle. Since a low boiling point refrigerant, for example, a non-azeotropic mixed refrigerant mixture of R-152a and R-221, is sealed, the evaporation temperature in each evaporator increases as it goes downstream. Multi-temperature refrigerator with one refrigeration cycle, for example -30℃ low temperature freezer compartment, -18℃ freezer compartment, +3
℃ constituted a cold room. In such a configuration, since the temperature of the low-temperature freezing chamber 4a is the lowest, it flows into the compressor 8 and condenses, so that the temperature of the low-temperature freezing chamber 4a rises. Also, a low temperature freezing chamber evaporator 7,
Since the freezer compartment evaporator 8 is connected and piped in series, it has the disadvantage that it is not possible to stop the low-temperature freezer compartment 4a and reduce the refrigeration load to save power.

OBJECTS OF THE INVENTION Therefore, the present invention prevents an unnecessary temperature rise caused by high-temperature and high-pressure refrigerant flowing into the low-temperature freezer compartment evaporator while the combrella two is stopped, and also controls the refrigerant inflow into the low-temperature freezer compartment evaporator. The purpose is to enable switching between operation and stop of the low-temperature freezer compartment, and further to reduce the cooling capacity of the freezer compartment evaporator when the low-temperature freezer compartment is used, and to fully utilize the cooling capacity of the low-temperature freezer compartment evaporator.

Structure of the Invention In order to achieve this object, the present invention provides a bypass circuit that connects a compressor, a condenser, a low-temperature freezing chamber evaporator, and a freezing chamber evaporator in series, bypassing the low-temperature freezing chamber evaporator, and a bypass circuit that bypasses the low-temperature freezing chamber evaporator and the freezing chamber evaporator. A solenoid valve is provided upstream of each to form a refrigeration cycle, and a non-azeotropic mixed refrigerant, which is a mixture of two types of refrigerants with different boiling points, is sealed in this refrigeration cycle, and the fan motor for cooling the freezer compartment operates at high speed. It is possible to switch between rotation and low-speed rotation, and when the low-temperature freezer is in use, the fan motor for cooling the freezer compartment rotates at low speed, and when the low-temperature freezer is not in use (stopped), the fan motor for cooling the freezer compartment is rotated at high speed. During operation, the heat exchange amount of the freezer compartment evaporator is reduced by slowing down the fan motor, the operating time of the compressor, which is controlled by the freezer compartment temperature, is extended, and the evaporation temperature of the low-temperature freezer compartment evaporator is sufficiently lowered. - When the low-temperature freezer is stopped, the heat exchange amount of the freezer compartment evaporator is optimized by increasing the speed of the fan motor.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. In Figures 3 and 4, 12 is the refrigerator main body, and the main body 1
2 is divided into a second compartment 16 (hereinafter referred to as the freezing compartment 16) and a refrigerator compartment 16 by a compartment wall 14 having a heat insulating material 13, and inside this compartment wall 14, the circulating air of the compartment 15. suction duct) 17.18. A second evaporator 20 (hereinafter referred to as finned evaporator 2o) 19 is connected to the rear opening of the suction duct 17, 1B on the back wall surface of the refrigerator main body 12, and is located above the suction duct 17, 18. This is a cooling chamber that is internally installed and has one end opened to the freezing chamber 16, and the upper opening 2 of this cooling chamber 19
1 is provided with a fan 22f. Reference numeral 23 denotes a discharge duct for causing cold air discharged from the fan 22 to flow into the refrigerator compartment 16. An automatic damper 26 that automatically controls the inflow of cold air is provided at the opening 24 of the refrigerator compartment 16, and The temperature is adjusted arbitrarily. Reference numeral 26 denotes a first compartment (hereinafter referred to as a low-temperature freezing room), which includes an outer box 27, a heat insulating material 28, a first evaporator 29 (hereinafter referred to as a plate type evaporator 29) that also serves as an inner box, and a defrosting heater 30. The thickness of the low-temperature freezing chamber main body 31 and the gasket is set to the thinnest thickness within the range that does not cause frost to form on the outer box 27 when the low-temperature freezing chamber 26 is being cooled, and does not have a large thermal effect on the inside of the freezing chamber 15 when defrosting. There is. Further, in order to enable service replacement, the low-temperature freezer compartment 26 is assembled in advance as a low-pressure unit with the freezer compartment evaporator 20 as shown in FIG. 4, and then installed in the refrigerator main body 12. Reference numeral 36 denotes a fitting for fixing the low-temperature freezing chamber 26 within the refrigerator main body 12, and is fixed so that a ventilation duct 36 is formed between the rear part of the upper part 2 of the low-temperature freezing chamber 26 and the inner surface of the refrigerator main body 12. 37
is a freezer compartment discharge duct, which has discharge ports at the front and at the top facing the ventilation duct 360-1" section, and cools the outer periphery of the low-temperature freezer compartment 26 and the freezer compartment 16 with cold air discharged from the fan 22. It is. 37 is a door of the freezer compartment 16, and 38 is a door of the refrigerator compartment 16.

°39 is an evaporation plate for evaporating defrosting water, 4Q is a hot plate condenser for promoting evaporation of defrosting water, 4
1.41' is a capacitor embedded in the inner surface of the outer box of the refrigerator main body 12, 42 is a compressor, and 43 is a combrella T42.
This is a ventilation duct for a cooling fan (not shown) that cools the air.

As shown in FIG. 5, the refrigeration cycle includes a compressor 42,
Hot plate capacitor 40, capacitor 41.41
A cooling circuit is constructed by connecting in this order the branch flow path 44, the first capillary tube 46, the grate type evaporator 29, the check valve 46, and the finned evaporator 20, and between the flow diverter 44 and the finned evaporator 20, A second capillary tube 48 bypassing the plate evaporator 29 is connected to the upstream side of the plate evaporator 29 and to the port of the second capillary tube 47 to control the refrigerant inflow into the evaporator 20.29. A solenoid valve A48 and a solenoid valve B49 are respectively arranged. Two types of refrigerants having different boiling points are mixed in an appropriate ratio (for example, R-22 and R-152a are mixed at a weight ratio of 50:60) in this refrigeration cycle.

The electrical circuit diagram is as shown in Figure 6, where 60 is a power supply, 51
62 is a defrosting timer for the finned evaporator 2o; 63 is a person who operates the low-temperature freezing room; a selector switch is used to turn it off; 64 is a cooling fan 22 for the freezing room 16. A high-speed rotation circuit 54a and a low-speed rotation circuit 5 are connected by tap switching using a fan motor that drives the
4b, the solenoid valve A48 and the low speed rotation circuit 64b of the fan motor 64 are connected in parallel, and this parallel circuit is connected to the "on" terminal 53a of the changeover switch 63.

Also, the solenoid valve B49 and the high-speed rotation circuit 64a of the fan motor 64 are connected in parallel, and the parallel circuit is connected to the selector switch 64.
A control circuit C is formed which connects to the "off" terminal 53b of the compressor 4 and controls the solenoid valves A48 and B49 and the fan motor 64 by means of a changeover switch 63, and the control circuit C and the compressor 4
2 are connected in parallel, and the parallel circuit and the normally closed contact 62a1 of the defrosting timer 62 and the temperature regulator 61 are respectively connected in series to form a cooling control circuit. 66 is a defrosting heater for the finned evaporator 20, and 66 is a bimetal for detecting the end of defrosting, which are connected in series, with one end connected to the normally open contact 62b of the defrosting timer 62, and the other end connected to the power source 60. Connected. 67 is a timer motor for automatically switching the contacts 52a and 52b of the defrosting timer 62 according to the accumulated time;
One end is connected to the opening/closing terminal side of the temperature regulator 61, and the other end is connected to a power source. 68 has a manual activation and automatic return function with the defrosting switch of the low temperature freezing chamber 26, and the temperature controller 61 and the normally closed contact 6.8a are connected in series, and the low temperature freezing is connected between the normally open contact 5sb and the power supply. Defrosting heater 3 in chamber 26
0 is connected.

In the above configuration, the temperature controller 61 is closed during the cooling operation when the low-temperature freezer is used (°° turned on), and the defrost switch 68 is closed.
, the defrosting timer 62, and the changeover switch 53 each form a normally closed circuit, so the fan motor 64 forms a low-speed rotation circuit 54b, so that the solenoid valve A48 is open and the solenoid valve B49 is closed.
is closed, forming a frozen cycle indicated by the dotted line in FIG.

That is, it is compressed by the compressor 42, and the condenser v41.4
The non-azeotropic mixed refrigerant liquefied in step 1' is depressurized by the first capillary tube 46 and enters the plate evaporator 29 of the low-temperature freezing chamber 26, where it starts evaporating at, for example, -36°C. Then, it evaporates in the grate type evaporator 29, and since it is a non-azeotropic mixed refrigerant, as the evaporation progresses, a liquid refrigerant with a high concentration of high boiling point refrigerant remains, and the evaporation temperature also rises. In this state, the refrigerant enters the fin evaporator 2o of the freezer compartment 15, where it evaporates at, for example, -30°C, and -24°C.
After completing the evaporation, everything becomes gaseous and becomes a combrella +
Return to j42. At this time, since the fan motor 54 is rotating at a low speed, the cooling capacity of the finned evaporator 20 of the freezing compartment 16 is reduced, and the evaporation temperature is maintained sufficient to lower the temperature of the low-temperature freezing compartment 26. At the same time, the operating time of the compressor 42 can be extended. Then, when the temperature regulator 61 is opened and the cooling operation is stopped, the solenoid valves A48 and B49 are closed, and the high-pressure and high-temperature refrigerant is transferred to the first capillary tube 46 and the second capillary tube 4.
7 into the respective evaporator 45, 47. In this way, ~30℃30℃
The temperature of the refrigerator compartment 16 is maintained at about 3°C by a moderate temperature freezing room 26, a freezing room 16 at about -18°C, and a damper thermostat 24.

Next, when the low-temperature freezer compartment 26 is not used (when it is turned off), the selector switch 63 is manually switched to the "off" side 54a.Then, the fan motor 64 forms a high-speed rotation circuit 54a, and the solenoid valve A48 is turned off. The circuit is closed, and the solenoid valve B49 is opened, forming the refrigeration cycle shown by the solid line in FIG.
Refrigerant is allowed to flow only through the finned evaporator 2o. Therefore, the refrigerating capacity to lower the inside of the low-temperature freezer compartment 26 to a low temperature is unnecessary, and since the fan motor 54 rotates at high speed, the amount of heat exchange is increased, and the evaporation temperature in the finned evaporator 20 is lowered to the minimum temperature (for example, − (36°C) without lowering it due to heating, and lowering it than when using the chamber, increasing its capacity,
The operating time of the compressor +j42 can be significantly reduced compared to when the low-temperature freezer compartment 26 is used (when it is "on"), and since the cold air discharge temperature does not drop extremely, the temperature setting of the freezer compartment 26 can be changed significantly. , the operation of the compressor 42 will not be extremely shortened, and suction of unevaporated liquid refrigerant into the compressor can also be prevented. or,
The inside of the low-temperature freezer compartment 26 is cooled by the cold air discharged from the fan 22 and the cold air inside the freezer compartment 16, so it has the same temperature as the freezer compartment 16, so it can be used as a freezer.

Next, the defrosting of the finned evaporator 20 in the freezer compartment 16 is automatically switched to the defrosting circuit according to the cumulative time of the timer motor 67, the compressor +j42 and the fan 22 are stopped, and the electromagnetic circuit at the inlet of the first capillary tube 45 is switched to the defrosting circuit. Valve A4B is closed. Then, the defrosting heater 56 is energized and the finned evaporator 20 is defrosted. At this time, there is a check valve on the upstream side of the finned evaporator 2Q, and the solenoid valve 48 is closed, so the gas refrigerant heated in the finned evaporator 20 does not flow into the plate type evaporator 29. It is possible to completely prevent thermal effects on the low temperature freezing chamber 26 due to defrosting of the finned evaporator 2o. When the defrosting is completed, the bimetal 66 for detecting the end of defrosting is opened and the energization to the defrosting heater 55 is canceled. After a certain period of time, the timer motor 6o automatically switches to the normally closed contact 62a and restarts the cooling operation.

Next, to defrost the plate type evaporator 29 in the low-temperature freezer compartment 26, when the defrost switch 68 is manually switched to the normally open contact 68b side, the cooling operation is stopped, and the defrost heater 30 is energized and the plate type evaporator 29 is defrosted. When the defrosting is completed, the defrost switch 58 is automatically switched to the normally closed contact 68a side and the cooling operation is resumed. Although the cooling operation is stopped during defrosting, since the defrosting time is short, the temperature in the freezer compartment 16 does not rise significantly.

Therefore, it is possible to provide a low-temperature freezing chamber 26 that maintains a stable low temperature without the high-temperature refrigerant flowing into the plate-type evaporator 29 of the low-temperature freezing chamber while the congressor is stopped and the fin coil evaporator 20 is defrosted. can. Furthermore, the low-temperature freezing chamber 26 can also be used as a freezing chamber, resulting in effects such as being able to save electricity.

Effects of the Invention As is clear from the above explanation, the present invention provides a low-temperature freezing chamber within the freezing chamber, each of which is equipped with a dedicated evaporator, and the evaporator for the low-temperature freezing chamber and the evaporator for the freezing chamber are connected in series. A bypass circuit is provided to bypass the evaporator for the low-temperature freezer compartment, a solenoid valve A is provided upstream of the evaporator for the low-temperature freezer compartment, and a solenoid valve B is provided in the bypass circuit, and a non-azeotropic refrigerant is sealed to form a refrigeration system. Equipped with a freezer temperature regulator, a switch to start and stop the low-temperature freezer, and a fan motor that can switch between high-speed and low-speed rotation.
The fan motor forms a low-speed rotation circuit, and controls the solenoid valve A, fan motor, and compressor in the freezer compartment temperature controller.
When the low-temperature freezer compartment is not in use (when “off”), turn off solenoid valve A.
The fan motor forms a high-speed rotation circuit that controls the freezer compartment temperature control valve B, the fan motor, and the compressor, so it is possible to prevent high-temperature, high-pressure refrigerant from flowing into both evaporators while the compressor is stopped. , the temperature rise in the low-temperature freezing room and freezing room can be minimized. or,
When the low-temperature freezing chamber is in use (C'' hours), the capacity of the evaporator for the freezing chamber is reduced, the operating time of the compressor is lengthened, and the evaporation temperature is lowered, thereby providing a low-temperature freezing chamber that can maintain a stable low temperature. In addition, when it is not used as a low-temperature freezing room (when turned off), it is used as a freezing room to reduce the refrigeration load on the compressor and optimize the evaporation temperature of the evaporator for the freezing room to increase its capacity as the heat exchange air volume increases. Since the compressor operating time is increased and the operating time of the compressor is shortened, it is possible to save power and to obtain effects such as reducing the amount of liquid refrigerant sucked into the compressor.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventional refrigerator, Fig. 2 is a conventional refrigeration cycle diagram, Fig. 3 is a sectional view of a refrigerator showing an embodiment of the present invention, and Fig. 4 is an assembly diagram of the main parts of Fig. 3. , FIG. 6 is a refrigeration cycle diagram of the present invention, and FIG. 6 is an electrical wiring diagram of the refrigerator of the present invention. 16...Second compartment, 20...Second
evaporator, 26...first compartment, 29
...First evaporator, 48.49...
... is a magnetic valve, 42... is a compressor, 64...
...Fan motor, 61.Old...Temperature controller, C.
...Control circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] A first compartment, a second compartment, a changeover switch for switching between operation and stop of the first compartment, a temperature controller for adjusting the temperature of the second compartment, and a temperature controller for adjusting the temperature of the second compartment; A first evaporator that cools the chamber, a second evaporator that cools the second compartment, a compressor, and a condenser, and a solenoid valve A, the first evaporator, and the second evaporator are connected in series; On the other hand, a bypass circuit having a solenoid valve A and a solenoid valve B that bypasses the first evaporator is installed, and a non-azeotropic mixed refrigerant obtained by mixing two types of refrigerants with different boiling points is sealed to form a cooling system; A fan motor capable of high-speed and low-speed operation is provided to blow cold air from the second evaporator.
The refrigerator includes a control circuit that operates the fan motor at a low speed while the first compartment is in operation in response to the stoppage, and operates the fan motor at a high speed while the first compartment is not operating.