JPH09152251A - refrigerator - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To improve the heat exchange efficiency of an evaporator and a condenser, to reduce the power consumption of an electric heater during defrosting, and to prevent condensation even if a flammable refrigerant is used. We provide a fan-cool type refrigerator that prevents dust from adhering to the container. A heat exchanger (condenser, evaporator) 7 is provided with a metal plate 23 that is bent in a concavo-convex shape. For example, the heat exchanger (condenser, evaporator) 7 is arranged so that the inlet side of the refrigerant is low and the outlet side thereof is high. The cross-sectional area is configured such that the refrigerant inlet side is small and the outlet side is large, and the tip portion and the root portion of the bent portion of the metal plate of the heat exchanger are configured so that the resistance during the progress of the refrigerant is reduced,
The heat exchanger is used as an evaporator, and the evaporator is arranged along a cold air duct, and the air that has been heat-exchanged with the two-phase region refrigerant of the evaporator is mainly guided to the freezer compartment to heat the overheat region refrigerant and the heat. The exchanged air is mainly configured to be guided to the refrigerator compartment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerator, and more particularly to a fan-cool type refrigerator in which an evaporator and the like are arranged in forced convection.

[0002]

2. Description of the Related Art Conventionally, a fan-cool type refrigerator is known as one type of refrigerator. In the fan-cool type refrigerator, a compressor, a condenser, a throttle mechanism, and an evaporator are sequentially connected to form a refrigeration cycle, and the evaporator is arranged in forced convection of air in a cooling duct. Is arranged so that it radiates heat when exposed to the outside air.

[0003]

However, in the conventional fan-cool type refrigerator, the following improvements have been desired.

Although the evaporator and the condenser have a function as a heat exchanger, improvement in heat exchange efficiency has been demanded for the conventional evaporator and condenser.

When the evaporator is frosted, defrosting may be performed by the electric power heater, but it has been desired to reduce power consumption and time required for defrosting.

Freon-based refrigerants have been mainly used as refrigerants, but in recent years, freons have become the main cause of depletion of the ozone layer surrounding the earth, and the use of freon-based refrigerants has been banned. Combustible refrigerants (such as isobutane) have come to be used in refrigerators as an alternative to CFCs, but if flammable refrigerants leak into the refrigerator, it may cause an explosion, etc. It is necessary to make every possible effort to prevent the leakage of the volatile refrigerant. Due to its nature, the condenser is placed in a place where it directly contacts the outside air, but dust is likely to adhere to it.

Therefore, an object of the present invention is to provide a refrigerator in which the above points are improved.

[0008]

In order to solve the above-mentioned problems, the invention according to claim 1 provides a refrigeration cycle in which a compressor, a condenser, a throttle mechanism and an evaporator are sequentially connected to form a refrigerant passage. In the provided refrigerator, the heat exchanger for the refrigerant passage is provided with a metal plate bent into an uneven shape, and the heat exchanger is used for at least one of the condenser and the evaporator.

According to the first aspect of the present invention, for example, a heat exchanger used as an evaporator is provided with a metal plate that is bent to have unevenness. If the bent portion of the unevenness of the evaporator having such a configuration is arranged in the forced convection of the cool air duct, the air-side heat transfer area is large, so that the cool air is efficiently sent into the refrigerator.

The invention as set forth in claim 2 is characterized in that the heat exchanger is arranged so as to be inclined so that the refrigerant inlet side is low and the refrigerant outlet side is high.

According to the second aspect of the invention, considering the case where the heat exchanger is used as an evaporator, as shown in FIG.
Deploy. In this case, the liquid refrigerant accumulates on the refrigerant inlet side, and the forced convection air is sufficiently cooled through the area where the refrigerant is accumulated and flows into the refrigerator. Therefore, the heat transfer coefficient of the refrigerant is improved and the heat exchange performance is improved.

The cross-sectional area of the bent portion of the metal plate in the heat exchanger in the refrigerant advancing direction is:
The refrigerant inlet side is small and the refrigerant outlet side is large.

According to the third aspect of the invention, as shown in FIG. 5, the flow passage cross-sectional area (cross-sectional area in the traveling direction) on the refrigerant outlet side of the evaporator is made large, so that the refrigerant outlet side. The pressure loss is reduced, and the flow velocity of the refrigerant flowing in the evaporator becomes slow. Therefore, since the cool air is sufficiently emitted, the heat transfer coefficient of the refrigerant is improved.

Further, in the invention according to claim 4, at least one of the tip end portion and the root portion of the bent portion of the metal plate of the heat exchanger is configured to reduce resistance when the refrigerant advances. It is characterized by

According to the fourth aspect of the present invention, as shown in FIG. 6, at least one of the tip portion and the root portion of the bent portion is formed flat. Therefore, the resistance of the progressing refrigerant decreases in this flat portion.

According to a fifth aspect of the present invention, the heat exchanger is used as an evaporator, the evaporator is arranged along a cool air duct, and air is heat-exchanged with a two-phase refrigerant of the evaporator. Is mainly introduced into the freezer compartment, and the air that has exchanged heat with the overheated region refrigerant is mainly introduced into the refrigerating compartment.

According to the fifth aspect of the invention, as shown in FIG. 7, the coldest air passing through the two-phase region (inlet side) of the refrigerant of the evaporator is flowed into the freezing chamber (arrow A), The slightly cooled air which has passed through the heating area (outlet side) of the refrigerant is flowed into the refrigerating chamber (arrow B). Therefore, it is possible to perform heat exchange in which air having a temperature suitable for each of the refrigerating room and the freezing room is introduced.

According to a sixth aspect of the present invention, the heat exchanger is used as a condenser, and the condenser is arranged on the bottom side of the refrigerator body with the bent surface of the metal plate facing downward. Characterize.

According to the invention of claim 6, since the bent surface of the metal plate of the condenser is arranged so as to face downward,
Dust is hard to attach.

The invention according to claim 7 is characterized in that the heat exchanger is used as an evaporator, and a heater for defrosting is directly connected to the evaporator.

According to the seventh aspect of the invention, as shown in FIG. 9, the defrosting heater is embedded in the metal plate of the evaporator. Therefore, the loss of the electric power applied to the heater can be reduced.

The invention according to claim 8 is characterized in that a non-azeotropic mixed refrigerant is used as a refrigerant, and the defrosting heater is installed near a refrigerant inlet of the evaporator.

According to the present invention, when a non-azeotropic mixed refrigerant is used, the temperature of the refrigerant inlet of the evaporator becomes lower than the temperature of the refrigerant outlet because of the temperature gradient due to the physical properties of the refrigerant. . Therefore, frost concentrates on the refrigerant inlet having a low temperature. Therefore, by directly embedding the defrosting heater on the refrigerant inlet side where frost easily forms, frost concentrated on the inlet side can be preferentially melted.

The invention according to claim 9 is characterized in that the refrigerant is a flammable refrigerant.

According to the ninth aspect of the invention, even if the refrigerant is a flammable refrigerant, since the joint portion of the evaporator is arranged in the cool air duct, even if the flammable refrigerant leaks, the refrigerator. It does not leak inside.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on an embodiment shown in the drawings.

(1) First Embodiment Example FIGS. 1A and 1B are views showing a fan-cool type refrigerator according to the present embodiment, wherein FIG. 1A is a vertical sectional view and FIG.

As shown in FIG. 1A, a vertically long refrigerator 1
Inside the refrigerator, a refrigerating room 2 with a suitable temperature of approximately + 3 ° C from the top
A freezing chamber 3 having an appropriate temperature of about -18 ° C and a vegetable chamber 4 having an appropriate temperature of about + 8 ° C are formed.

A compressor 5, a condenser (not shown), and a blower 6 for radiating heat from the condenser are arranged on the lower right side (rear side) of the refrigerator 1, and are arranged on the rear side of the freezer compartment 3. Inside the duct 9, an evaporator 7 and a blower 8 for cooling the interior are arranged.

The peripheral portion of the evaporator 7 is constructed as shown in FIG. 1 (b). That is, on the back side of the evaporator 7, a heat insulating cover 11 having a heat insulating material 14 incorporated therein is arranged, and in the heat insulating cover 11, an inlet pipe 12 and an outlet pipe 13 which form a refrigerant pipe of the evaporator 7 are arranged. ing. With this structure, heat radiation from the back side of the evaporator 7 is reduced. A saucer 15 for receiving the water thawed at the time of defrosting is arranged immediately below the evaporator 7.

Here, the detailed configuration of the evaporator 7 will be described with reference to FIGS. 2 (a), 2 (b) and 3.

As shown in FIGS. 2 (a), (b) and FIG.
The evaporator 7 includes a back plate 21, a bending plate 23, and an upper closing plate 24.
And a lower closing plate 25 and the like.

The back plate 21 is formed of a metal plate in the shape of a slightly oblong rectangle. Protrusions 22c and 22d are formed along the upper and lower sides of the rectangle, and the insides of the protrusions 22c and 22d are formed. Has a horizontally long groove 22a,
22b are formed. A refrigerant inlet pipe 12 is provided on the lower side projection 22d in a rearward direction, and a refrigerant outlet pipe 13 is provided on the upper side projection 22c.

The bent plate 23 is formed by bending a metal plate made of copper or the like in a bellows shape (uneven shape), a root portion 23a is formed flat, and a tip is formed sharp. Inside the bent plate 23, a space portion 23b that serves as a flow path for the refrigerant is formed.

The upper closing plate 24 and the lower closing plate 25
Are formed of metal plates made of copper or the like, and are formed in a sawtooth shape so as to close the bent portions of the bent plate 23.

The refrigerant flowing in through the inlet pipe 12 has a space 23b formed by the bent plate 23 and the like.
Through the outlet pipe 13 to a suction pipe (not shown). While this refrigerant is flowing, the blower 8 forcedly convects the air in the valley portion of the bent plate 23, and the cooled air is sent to the freezer compartment 3 and the duct 9.

In this way, since the bent plate 23 expands the heat transfer area on the air side of the evaporator 7, the cooling efficiency is improved, and the bent pipe and the fine cooling fin as in the conventional case are used. Since there is no frost, it is sufficient to melt the frost adhering to the root at the time of defrosting, so that the frost is easily dropped and the heater power at the time of defrosting is reduced.

(2) Second Embodiment Example This embodiment example, as shown in FIG. 4, is a duct 9 of a refrigerator.
Inside the evaporator 7, the refrigerant inlet pipe 13 side is set low,
This is the case where the refrigerant outlet pipe 12 side is installed so as to be inclined.

When the evaporator 7 is installed in this way, the liquid refrigerant 26 collects at the inlet side of the evaporator 7, and the forced convection air (arrow C) is sufficiently cooled through the place where the refrigerant 26 collects. Pouring into the refrigerator in the open state.

Therefore, the heat transfer coefficient of the refrigerant 26 is improved, the heat exchange performance is improved, and the evaporator 7 can be downsized and energy can be saved.

(3) Third Embodiment In this embodiment, as shown in FIG. 5, the height of the convex portion of the bent plate 23A of the evaporator 7A is lowered on the refrigerant inlet pipe 13 side so that the refrigerant This is a case where the outlet pipe 12 side is configured to be high.

The state of the refrigerant in the evaporator 7A is a two-phase region (two phases of liquid and gas) in which the dryness is small on the inlet side and the flow velocity is slow.
Therefore, the outlet side becomes an overheating region with a large specific volume and a high flow velocity.

Therefore, when the evaporator 7A is constructed as described above, the flow passage cross-sectional area on the outlet side is made large, so that the pressure loss on the evaporation side (outlet side) is reduced and the inside of the evaporator 7A is reduced. The flow velocity of the flowing refrigerant can be properly secured.

Therefore, since the heat transfer coefficient of the refrigerant is improved and the heat exchange performance is improved, the evaporator 7A can be downsized and energy saving can be achieved.

(4) Fourth Embodiment Example This embodiment example is a case where the tip portion 23Ba of the bent plate 23B of the evaporator (heat exchanger) 7B is formed flat as shown in FIG.

According to this structure, the refrigerant easily flows in the tip portion 23Ba of the bent plate 23B, and the temperature boundary layer of air near the outside of the tip portion 23Ba becomes thin.

Therefore, since the heat transfer coefficient of the refrigerant is improved and the heat exchange performance is improved, downsizing of the evaporator 7B and energy saving can be achieved.

(5) Fifth Embodiment Example This embodiment example is a case where the root portion 23Bb of the bent plate 23B of the evaporator (heat exchanger) 7B is formed flat as shown in FIG.

According to this structure, the air in the root portion 23Bb of the bending plate 23B can easily flow, and the root portion 23Bb can easily flow.
The temperature boundary layer of the air in the vicinity of becomes thin.

Therefore, the heat transfer coefficient on the air side is improved and the heat exchange performance is improved, so that the evaporator 7B can be downsized and energy can be saved.

(6) Sixth Embodiment Example In this embodiment example, as shown in FIG.
The coldest air that has passed through the phase region is the freezing chamber 3 (about -18
C.) (arrow A), and the slightly cooled air that has passed through the refrigerant outlet side (superheated region) is flowed to the refrigerating chamber 2 (about + 3.degree. C.) (arrow B).

With this structure, heat can be exchanged in the refrigerator 1 so that the air having a temperature suitable for the refrigerating room 2 and the air for the freezing room 3 can be introduced, and the evaporator 7 can be effectively used.

Therefore, energy saving can be achieved by improving the heat exchange performance.

(7) Seventh Embodiment This embodiment relates to a refrigeration cycle, and FIG. 8 shows the refrigeration cycle.

As shown in FIG. 8, the refrigerating cycle of the present embodiment uses an electric expansion valve 31 capable of throttling operation and full opening operation instead of the capillary (throttle).

During normal operation, the electric expansion valve 31 is used for throttling, and during defrosting, the electric expansion valve 31 is fully opened, and the high temperature refrigerant in the condenser 32 is introduced into the evaporator 7 to remove the evaporator 7. Do frost.

In this way, compared with the conventional evaporator,
The evaporator 7 (see FIG. 2) has a very simple shape (there is no conventional pipe or fine fin), and frost easily falls along the uneven portion of the bent plate 23, so that high temperature and high pressure gas It is possible to easily drop the frost by melting the frost at the base of the evaporator 7 by the hot gas type defrosting for blowing.

Therefore, since the temperature of the evaporator 7 during defrosting can be kept low, the temperature inside the refrigerator does not rise during defrosting and the deterioration of the food in the refrigerator 1 can be prevented. Further, since the defrosting heater can be eliminated by hot gas defrosting, the power consumption of the refrigerator can be reduced.

(8) Eighth Embodiment Example This embodiment example is shown in FIG. As shown in FIG. 9, in the present embodiment, the defrosting heater 33 is directly embedded in the evaporator 7.

Such direct embedding is possible because the evaporator 7 is made of a metal plate and has a simple shape. That is, it is impossible to directly embed the heater because the conventional evaporator has a complicated shape.

The heater energization time at this time can be defrosted in a considerably shorter time than in the conventional case. The reason is that conventionally, a defrosting heater is installed near the evaporator,
The radiant heat was used to melt the frost. On the other hand, in the present embodiment, the method of directly heating the evaporator 7 is adopted, so that the thermal efficiency is good.

Therefore, since the defrosting time can be suppressed to be short,
The power consumption of the heater can be reduced and energy saving can be achieved.

(9) Ninth Embodiment Example The present embodiment example uses a non-azeotropic mixed refrigerant, and FIG. 10 shows the installation position of the defrosting heater 34 of the present embodiment example. is there.

When a non-azeotropic mixed refrigerant is used, the temperature on the inlet pipe 12 side of the evaporator 7 becomes lower than the temperature on the outlet pipe 13 side because of the temperature gradient depending on the physical properties of the refrigerant.

Under this condition, frost concentrates on the inlet pipe 12 side of the evaporator having a low temperature. Therefore, in this embodiment, the heater 33 is provided on the side of the inlet pipe 12 where frost is likely to occur.
Was directly embedded.

According to this structure, the frost concentrated on the inlet pipe 12 side can be preferentially melted.

Therefore, by improving the defrosting efficiency, the power consumption of the heater can be reduced and energy saving can be achieved.

(10) Tenth Embodiment As shown in FIGS. 1 (a) and 1 (b), the evaporator 7 having the bent plate 23 is arranged in a duct 9 outside the refrigerator 1.

Therefore, in the conventional find tube having a pipe through which the refrigerant flows in the air passage in the refrigerator, the pipe is exposed in the refrigerator, but in the present embodiment, the pipe is exposed in the refrigerator. In addition, the welded portion of the pipe can be installed outside the refrigerator.

Therefore, the possibility that the refrigerant leaks into the refrigerator is extremely low as compared with the conventional case, and it becomes possible to comply with the UL standard and the like. Moreover, when a flammable refrigerant is used, there is no risk of fire or explosion in the refrigerator, and safety is improved.

(11) Eleventh Embodiment This embodiment relates to a method for manufacturing the bent plate 23.

As shown in FIG. 11, the metal material 41 is pressed into the female die 42 to form the bent plate 23. Here, female mold 4
Holes corresponding to the unevenness of the bent plate 23 are formed inside the member 2.

As described above, the bending plate 23 formed by the extrusion process has a high strength and can enhance the safety when a flammable refrigerant is used.

(12) Twelfth Embodiment Example This embodiment example relates to a method of manufacturing the bending plate 23.

As shown in FIG. 12, an upper die 43 and a lower die 44 corresponding to the unevenness of the bending plate 23 are arranged to face each other, and the metal plate 4
The bent portion is press-molded in No. 5.

If the press working is performed in this manner, the manufacturing process can be shortened and the manufacturing cost of the lower bent plate can be reduced.

In the above embodiment, the case where the heat exchanger is used as the evaporator has been described, but it goes without saying that the heat exchanger may be used as the condenser.

[0078]

As described above, according to the invention described in each of the claims, in the fan-cool type refrigerator, the heat exchanger (condenser or evaporator) for the refrigerant passage is a metal plate bent in an uneven shape. The heat exchanger is arranged so that the refrigerant inlet side is low and the refrigerant outlet side is inclined so that the refrigerant outlet side is high, and the cross-sectional area of the bent portion of the metal plate in the heat exchanger in the refrigerant advancing direction is the refrigerant inlet side. Small, the refrigerant outlet side is configured large, the tip of the bent portion of the metal plate of the heat exchanger is configured to reduce the resistance when the refrigerant progresses, the heat exchanger is used as an evaporator, The evaporator is arranged along the cool air duct, and the air that has undergone heat exchange with the two-phase region refrigerant of the evaporator is mainly guided to the freezing chamber, and the air that has undergone heat exchange with the superheat region refrigerant mainly leads to the refrigerating chamber. The heat exchanger is configured as a condenser The condenser is arranged on the bottom side of the refrigerator main body with the bent surface of the metal plate facing downward, the heat exchanger is used as an evaporator, and a defrosting heater is directly connected to the evaporator. , A non-azeotropic mixed refrigerant is used as the refrigerant, the defrosting heater is installed near the refrigerant inlet of the evaporator, and since the refrigerant is a flammable refrigerant, the heat exchange efficiency of the evaporator and the condenser is improved. , Power consumption is reduced during defrosting, defrosting time is shortened, and even if a flammable refrigerant (such as isobutane) is used, leakage into the refrigerator is prevented,
Even when used as a condenser, since the bent portion of the metal plate faces downward, dust is unlikely to adhere.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment example of the present invention,
(A) is a longitudinal cross-sectional view of the refrigerator, and (b) is a main-portion cross-sectional view.

2A and 2B are views showing an evaporator according to the first embodiment, wherein FIG. 2A is a front perspective view of the evaporator, and FIG. 2B is a rear perspective view of the evaporator.

FIG. 3 is an exploded perspective view of the evaporator.

FIG. 4 is a cross-sectional view showing an arrangement posture of the evaporator.

FIG. 5 is a perspective view of an evaporator according to the third embodiment.

FIG. 6 is a sectional view of an evaporator according to the fourth embodiment.

FIG. 7 is a diagram showing a path of cold air that has passed through the evaporator of the sixth embodiment.

FIG. 8 is a diagram showing a refrigeration cycle of the seventh embodiment.

FIG. 9 is a diagram showing the arrangement of heaters for defrosting of the eighth embodiment.

FIG. 10 is a view showing the arrangement of defrosting heaters according to the ninth embodiment.

FIG. 11 is a diagram showing a method for manufacturing a bending plate according to the eleventh embodiment.

FIG. 12 is a diagram showing a method of manufacturing a bending plate according to the twelfth embodiment.

[Explanation of symbols]

 1 Refrigerator 2 Refrigerator 3 Refrigerator 4 Vegetable Room 5 Compressor 6 Radiator Blower 7, 7A, 7B Evaporator 8 Cooling Fan Blower 9 Duct 12 Inlet Pipe 13 Outlet Pipe 21 Back Plate 23 Bending Plate 24 Top Block 25 Lower closing plate 31 Electric expansion valve 32 Condenser 33, 34 Defrost heater

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takao Kojima 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture

Claims (9)

[Claims] 1. A refrigerator provided with a refrigeration cycle in which a compressor, a condenser, a throttle mechanism and an evaporator are sequentially connected to form a refrigerant passage, and a heat exchanger for the refrigerant passage is unevenly bent. A refrigerator comprising a metal plate, wherein the heat exchanger is used for at least one of the condenser and the evaporator. 2. The refrigerator according to claim 1, wherein the heat exchanger is arranged so that the refrigerant inlet side is low and the refrigerant outlet side is high. 3. The refrigerator according to claim 1, wherein a cross-sectional area of the bent portion of the metal plate in the heat exchanger in the refrigerant advancing direction is small on the refrigerant inlet side and large on the refrigerant outlet side. 4. The refrigerator according to claim 1, wherein a tip portion of the bent portion of the metal plate of the heat exchanger is configured to have a low resistance when the refrigerant advances. 5. The heat exchanger is used as an evaporator,
The evaporator is arranged along a cool air duct and
2. The air heat-exchanged with the phase refrigerant is mainly introduced into the freezer compartment, and the air heat-exchanged with the superheat area refrigerant is mainly introduced into the refrigerating compartment. refrigerator. 6. The heat exchanger is used as a condenser,
The refrigerator according to claim 1, wherein the condenser is arranged on the bottom side of the refrigerator body with the bent surface of the metal plate facing downward. 7. The heat exchanger is used as an evaporator,
The refrigerator according to claim 1, wherein a defrosting heater is directly connected to the evaporator. 8. A non-azeotropic mixed refrigerant is used as the refrigerant,
The refrigerator according to claim 7, wherein the defrosting heater is installed near a refrigerant inlet of the evaporator. 9. The refrigerator according to claim 1, wherein the refrigerant is a flammable refrigerant.