JP5369157B2 - Freezer refrigerator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a refrigerator-freezer performing efficient defrosting in a hot gas bypass system, reducing electric power consumption and preventing rise in the interior temperature to improve food quality. <P>SOLUTION: A refrigerating cycle includes a main circuit 6 and a bypass circuit 9, and a cooling chamber 17 is provided on the interior back face side. An evaporator 5, an evaporator fan 23 and a tray 19 are provided. Tray piping 8 is provided along the tray 19. During defrosting operation, a three-way valve 2 is switched to the bypass circuit 9 in an evaporator defrosting section and a tray defrosting section, and the valve is switched to the main circuit 6 in the evaporator cooling section so that a compressor 1 is operated in changing frequency in accordance with each defrosting section. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  The present invention relates to a refrigerator-freezer, and more specifically, it can efficiently defrost with a hot gas bypass type to reduce power consumption and prevent an increase in temperature in the cabinet, thereby improving the storage quality of food. It relates to a freezer refrigerator.

  The refrigeration cycle of the refrigerator / freezer is composed of a compressor, a condenser, a capillary tube, and an evaporator in this order, and cools the air in the cabinet by the evaporator. The air cooled by the evaporator is sent out to a room (a refrigerator room, a freezer room, a vegetable room, etc.) by an internal fan, and constitutes a circulation air path that returns from the room to the evaporator again. Moisture that is contained in room air by opening and closing doors and foods adheres to the surface of the low-temperature evaporator and forms frost. When the cooling operation is performed for about one day, the evaporator is covered with frost, the ventilation resistance of the evaporator is increased and the air volume is decreased, and the thermal resistance between the refrigerant and the air is increased and the refrigeration capacity is decreased. Therefore, it is necessary to defrost the evaporator once a day in order to prevent a decrease in capacity.

The conventional defrosting means of a refrigerator / freezer has a method of connecting the refrigerant flow path to the bypass pipe between the compressor and the condenser and between the capillary tube and the evaporator with a bypass pipe during defrosting operation. is there. Further, an operation method is disclosed in which the compressor is stopped when the evaporator reaches a predetermined temperature during the defrosting operation. Furthermore, an operation method is disclosed in which a heater is disposed in a tray section disposed in the lower part of the evaporator, and the heater is heated when the temperature of the tray section reaches around 0 ° C. (see, for example, Patent Document 1).
In addition, there is a conventional defrosting means in which a hot gas bypass circuit is provided in a refrigeration cycle so that hot gas flows through an evaporator via a drain pan (for example, see Patent Document 2).

Japanese Patent Laying-Open No. 2005-249254 (pages 4-5, FIGS. 1-2) JP 61-159072 (page 3, FIG. 1)

Although current refrigerators generally use heater-type defrosting, when the evaporator is disposed in the vicinity of the freezer compartment, the rate at which the heat of the heater leaks into the cabinet is high, increasing the power consumption. In the hot gas type, the cooler can be directly heated, but there is a problem that frost falls and remains on the tray, or heat is released from the compressor shell and much heat is available for defrosting.
In the refrigerator-freezer disclosed in Patent Document 1, a hot gas method is used for defrosting the evaporator and a heater method is used for defrosting the tray. Therefore, the effect of power saving is insufficient, and the configuration is complicated in that it is used together with a hot gas circuit. In addition, immediately after the defrosting is completed, normal operation is immediately started. Therefore, the heat of the evaporator heated at the time of defrosting is radiated into the cabinet, and the temperature inside the cabinet rises to consume useless power for cooling. As well as problems such as reducing food quality.
The defrosting means disclosed in Patent Document 2 uses a hot gas method for defrosting the tray and the evaporator, but does not consider operation for power saving.

  The present invention has been made in order to solve the above-mentioned problems, and is efficiently defrosted by a hot gas bypass type to reduce power consumption and prevent a temperature rise in the warehouse, thereby improving the storage quality of food. An object is to provide a refrigerator-freezer that can be improved.

In the refrigerator-freezer according to the present invention, the refrigeration cycle has a main circuit configured in the order of a compressor, a three-way valve, a condenser, a capillary tube, an evaporator, and a suction pipe, and branches in the three-way valve. A bypass circuit connected to the inlet, having a cooling chamber on the back side in the cabinet, the cooling chamber having the evaporator, an evaporator fan, and a tray, providing a tray pipe along the tray, The cycle defrosting operation consists of an evaporator defrosting section, a tray defrosting section, and an evaporator cooling section. In the evaporator defrosting section, the evaporator fan is stopped and the compressor frequency is minimized. After reducing to the rotational speed, the three-way valve is switched to the bypass circuit and the compressor is operated at a predetermined frequency higher than that during normal operation. In the tray defrosting section, the compressor is set in the evaporator defrosting section. Lower than frequency In the evaporator cooling section, after the three-way valve is switched to the main circuit, the compressor is operated at a frequency higher than the frequency of the tray defrost section, and the evaporator fan at the end of the defrost operation It is characterized by driving .

  According to the refrigerator-freezer of this invention, it can defrost efficiently with a hot gas bypass type | mold, can reduce the power consumption, can prevent the temperature rise in a warehouse, and can improve the preservation | save quality of foodstuffs.

It is a circuit diagram of the refrigerating cycle of the refrigerator-freezer which concerns on Embodiment 1 of this invention. 2 is a rear view of the refrigerator-freezer according to Embodiment 1. FIG. 3 is a front view of a cooling chamber of the refrigerator-freezer according to Embodiment 1. FIG. It is the front view and side view of a tray of the refrigerator-freezer according to Embodiment 1. 3 is a top view of the tray piping of the refrigerator-freezer according to Embodiment 1. FIG. 3 is a top view of the tray piping of the refrigerator-freezer according to Embodiment 1. FIG. 3 is a top view of the tray piping of the refrigerator-freezer according to Embodiment 1. FIG. It is explanatory drawing of the path | pass structure of the evaporator of the freezer refrigerator which concerns on Embodiment 1. FIG. 3 is a control diagram of the refrigerator-freezer according to Embodiment 1. FIG. It is a rear view of the refrigerator-freezer which concerns on Embodiment 2 of this invention. It is a front view of the cooling chamber of the refrigerator-freezer which concerns on Embodiment 2 of this invention. It is a top view of tray piping of the refrigerator-freezer according to Embodiment 2. It is a top view of tray piping of the refrigerator-freezer according to Embodiment 2. It is a top view of tray piping of the refrigerator-freezer according to Embodiment 2. It is a circuit diagram of the refrigerating cycle which concerns on Embodiment 3 of this invention. It is a rear view of the refrigerator-freezer according to Embodiment 3. It is a front view of the cooling chamber of the refrigerator-freezer according to Embodiment 3. It is a control diagram of the refrigerator-freezer according to Embodiment 3. It is a front view of the cooling chamber of the refrigerator-freezer which concerns on Embodiment 4 of this invention. It is a front view of the cooling chamber of the refrigerator-freezer according to Embodiment 4. It is a front view of the cooling chamber of the refrigerator-freezer which concerns on Embodiment 5 of this invention. It is a front view of the cooling chamber of the refrigerator-freezer which concerns on Embodiment 6 of this invention.

Embodiment 1 FIG.
In FIG. 1 showing the refrigerant circuit of the refrigerator-freezer according to Embodiment 1 of the present invention, the refrigeration cycle is composed of a compressor 1, a three-way valve 2, a condenser 3, a capillary tube 4, an evaporator 5, and an intake pipe 22 in this order. The main circuit 6 exchanges heat between the capillary 4 and the suction pipe 22, and the bypass circuit 9 is branched by the three-way valve 2 and connected to the throttle 7, the tray pipe 8, and the evaporator 5. And the evaporator fan 23 which ventilates the air cooled with the evaporator 5 in the store | warehouse | chamber is provided.

  In FIG. 2 showing the back of the refrigerator, a machine room 10 is provided below the back, and in the machine room 10, a compressor 1, a three-way valve 2, a machine room fan 11, a condenser 3, and a drain pan 13 are provided. A dryer 14 is provided. The piping of the main circuit 6 of the refrigeration cycle is connected from the compressor 1 to the three-way valve 2 and the condenser 3, and after exiting the condenser 3, is connected to piping installed inside the steel plate 15 of the refrigerator. On the other hand, after exiting the three-way valve 2, the bypass circuit 9 passes through the inside of the heat insulating wall 16 on the back of the refrigerator and enters the refrigerator through the hole 18 at the cooling chamber inlet.

  If the pipe from the three-way valve 2 to the hole 18 at the cooling chamber inlet is passed through the range from the center to the outer half in the thickness direction inside the heat insulating wall 16 on the back of the refrigerator, heat insulation is good and wasteful heat dissipation can be prevented. The heat of hot gas can be efficiently used for defrosting. However, when the pipe touches the steel plate 15 on the back surface, heat is easily released to the outside due to the fin effect, so that the steel plate 15 is not touched.

  In FIG. 3 when the cooling chamber is viewed from the front side of the door, an evaporator 5 is disposed at the center of the cooling chamber 17, and an evaporator that blows air cooled by the evaporator 5 into the chamber at the upper portion thereof. A fan 23 is provided. A tray 19 (see FIG. 4) formed of an aluminum plate, a steel plate, or the like is disposed at the lower part of the evaporator 5, and the bypass circuit 9 introduced from the hole 18 at the cooling chamber entrance is located next to the evaporator 5. And is bent along the tray 19 at the bottom (hereinafter referred to as tray pipe 8). The tray pipe 8 is then connected to the inlet of the evaporator 5.

4 and 5, the tray 19 has a width of about 400 mm and a depth of about 70 mm, and a drain port 20 is opened at the center. On the upper surface of the tray 19, the tray pipe 8 is bent 6 times in a meandering manner so as to be along the drain outlet 20.
When the tray pipe 8 is meandered, the heat transfer area with the frost increases and the defrosting time can be shortened. A drain hose is connected to the end of the drain port 20, and the drain flows from the tray 19 through the drain hose to the drain pan 13 of the machine room 10. The drain port 20 may be frozen and blocked during the cooling operation, and if the drain port 20 is blocked at the start of defrosting, the drain overflows from the tray 19 and leaks into the cabinet. Therefore, as shown in FIG. 5, by passing the tray pipe 8 along the circumference of the drain port 20, the drain port 20 is warmed simultaneously with the defrosting operation and the ice in the drain port 20 melts, so that the drain overflows. Can be prevented.

  The defrosting time is faster when the tray pipe 8 is placed along the whole of the tray 19, but the size of the tray 19 is about 400 mm wide and about 70 mm deep, the tray pipe 8 is made of copper and has a diameter of 4 mm and a wall thickness of 0.3 mm. In this case, the minimum radius of bending is about 15 mm, and even if it is meandering, it is at most 6 or 7 reciprocations. The inlet and outlet pipes of the evaporator 5 are unified on the side closer to the hole 18 at the cooling chamber inlet so as to simplify the handling. The entry and exit of the tray pipe 8 are also unified on the same side as the cooling chamber inlet hole 18 and the evaporator inlet, so that the pipe can be connected without waste.

In this case, the tray 19 may be arranged so that the tray pipe 8 is wound around the circumference of the drain port 20 as shown in FIG. This makes it easier to heat the drain port 20 than in the case of FIG.
Further, as shown in FIG. 7, the tray pipe 8 may pass over the drain outlet 20 of the tray 19. If it carries out like this, since the drain port 20 will be warmed simultaneously with a defrost operation and the ice of the drain port 20 will melt, it can prevent that drain overflows from the tray 19. FIG. Further, since the tray pipe 8 is arranged in the width direction of the tray 19, the number of bendings is reduced and the productivity is better than the meandering. When the tray pipe 8 passes over the drain port 20, the radius of bending is 15 mm or more, and the entrance and exit of the tray pipe 8 are unified on the same side, the pipe shape shown in FIG. 7 is obtained.

Next, the operation will be described.
In the normal cooling operation, the discharge gas of the compressor 1 is caused to flow to the main circuit 6 by the three-way valve 2 and the bypass circuit 9 is closed. The gas refrigerant compressed to a high temperature and high pressure by the compressor 1 dissipates heat to the outside by the condenser 3 and is condensed into a liquid refrigerant, becomes a low temperature and low pressure by the capillary 4, and sucks heat from the air by the evaporator 5 to generate the refrigerant. Evaporate. The air cooled by passing through the evaporator 5 circulates in the cabinet to cool each chamber. At this time, since moisture from the door opening and closing and food is turned into frost in the evaporator 5, when the cooling operation is performed for about one day, the evaporator 5 is covered with frost, the ventilation resistance is increased, and the air volume is reduced. The heat resistance between the air and the air increases and the refrigeration capacity decreases. Therefore, it is necessary to defrost the evaporator 5 about once a day in order to prevent a decrease in capacity.

  In the defrosting operation, the discharge gas of the compressor 1 is caused to flow through the bypass circuit 9 by the three-way valve 2 and the main circuit 6 is closed. A high-temperature gas refrigerant flows into the evaporator 5 through the tray pipe 8 and melts the frost in the evaporator 5. Since the frost in the evaporator 5 melts from the pipe and the fin surface, the frost slides down from the upper part of the evaporator 5 to the lower part, and the frost falls on the tray 19 below the evaporator 5. Therefore, since frost tends to remain in the lower part of the evaporator 5, as shown in FIG. 8, if the heat transfer tube has a path configuration in which a high-temperature refrigerant flows from the lower part of the evaporator 5 in the direction of the arrow, the frost on the lower part of the evaporator 5 It becomes easy to melt. In addition, if the cooling operation is restarted with the frost remaining on the tray 19, the frost grows large and eventually closes the air passage and the cold air may not reach the room and may not be cooled. Is melted by the tray pipe 8.

Next, the control operation will be described with reference to FIG.
When the defrosting operation is started, the evaporator fan 23 is stopped, the three-way valve 2 is switched, the discharge gas of the compressor 1 is caused to flow into the bypass circuit 9, and the compressor frequency is changed to the defrosting frequency α (STEP1). ). In general, since the compressor is operated at a lower frequency during normal operation, the defrosting frequency α is higher than the frequency during normal operation. The defrosting time can be shortened by setting the value as large as possible in consideration of the current value limitation and the liquid back reliability to the compressor 1. When the three-way valve 2 is switched to the bypass circuit 9, the high and low pressures approach a pressure equalization state, so that the refrigerant suddenly flows into the bypass circuit 9 and a refrigerant sound is generated. Therefore, before switching the three-way valve 2 to the bypass circuit 9, The compressor frequency may be reduced or the compressor 1 may be stopped. At this time, if the compressor 1 is stopped, it is necessary to secure time until restart for reliability, and it takes time for defrosting. Therefore, the compressor frequency is reduced to the minimum rotation speed. More preferred.

  Next, when the temperature of the evaporator 5 becomes Te ° C., the compressor frequency β is changed (STEP 2). The compressor frequency β takes a value necessary for melting the frost dropped on the tray 19, but if the frequency is large, the evaporator 5 is overheated, and therefore a value smaller than the defrosting frequency α is desirable. Te ° C. is a value equal to or higher than 0 ° C., and is a temperature set to ensure defrosting of the evaporator 5. Further, when the tray temperature becomes equal to or higher than Tt ° C., the three-way valve 2 is switched from the bypass circuit 9 to the main circuit 6 and changed to the compressor frequency γ (STEP 3). The compressor frequency γ is a value set for cooling the evaporator 5, and is set to a value larger than the compressor frequency β in order to cool it as soon as possible. At this time, since the evaporator fan 23 is stopped, the compressor frequency γ may be set to a large value so that the low pressure does not decrease too much. Tt ° C. is a value equal to or higher than 0 ° C., and is a temperature set for reliably melting the frost on the tray 19. Further, when the temperature of the evaporator 5 becomes equal to or lower than the predetermined temperature, the defrosting operation is terminated, and the evaporator fan 23 is operated to shift to the normal operation (STEP 4). The operation after STEP 3 is a time provided for cooling the evaporator 5, and the defrosting operation may be terminated after a predetermined time regardless of the temperature of the evaporator 5.

  The compressor 1 in the machine room 10 is a low-pressure shell, and the discharge pipe is routed in the shell to dissipate heat. The shell is forcibly air-cooled from the outside by the machine room fan 11 and can be used for defrosting. Heat is exhausted into the machine room 10. For this reason, if the rotation speed of the machine room fan 11 is reduced or stopped during defrosting in order to reduce shell heat dissipation, heat used for defrosting increases.

  As described above, according to the first embodiment, in the hot gas bypass defrosting of the refrigerator-freezer, the residual frost on the tray 19 is efficiently processed with the hot gas, so that the defrosting time is shortened and energy is saved. The rise of the internal temperature can be suppressed and the quality of the food can be kept good.

Embodiment 2. FIG.
In the first embodiment, the case where the bypass circuit 9 is introduced into the cabinet from the back of the cooling chamber 17 is shown. However, in the second embodiment, the bypass circuit 9 is introduced from the drain port 20 of the tray 19 into the cooling chamber 17. Show the case. FIG. 10 is a rear view of the refrigerator-freezer according to the second embodiment. A machine room 10 is provided on the lower side of the back surface, and the compressor 1, the three-way valve 2, the machine room fan 11, and the condenser 3 are provided in the machine room 10. A drain pan 13 and a dryer 14 are provided. The piping of the main circuit 6 of the refrigeration cycle is connected to the three-way valve 2 and the forced air-cooled condenser 3 from the compressor 1, and after exiting the forced air-cooled condenser 3, it is connected to the piping installed inside the steel plate 15 of the refrigerator. Is done. On the other hand, the bypass circuit 9 passes through the drain pipe after exiting the three-way valve 2 and is introduced into the cooling chamber 17 from the drain port 20 of the tray 19.

  FIG. 11 is a view of the cooling chamber 17 as seen from the front side of the door. The evaporator 5 is disposed at the center of the cooling chamber 17. A tray 19 is provided below the evaporator 5, and the drainage of the tray 19 is performed. The bypass circuit 9 introduced from the opening 20 is bent along the tray 19.

FIG. 12 shows the tray pipe 8, and a drain port 20 is opened at the center of the tray 19, and the bypass circuit 9 extends along the tray 19 so as to enter the inside from the drain port 20 and draw a ““ ”shape. It has a different shape. If the pipe is made of copper and has an outer diameter of 4 mm and a wall thickness of about 0.3 mm, the radius of the minimum bending of the pipe is about 15 mm and the depth of the tray 19 is as narrow as 60 to 80 mm. In the case of the “-” shape, it is possible to arrange the pipes in the entire tray 19 without overlapping the pipes, and the end point of the tray pipe 8 becomes the corner of the tray 19, and the connection to the inlet of the evaporator 5 becomes easy.
Further, when a part of the “-” shape is meandered as shown in FIG. 13, the heat transfer area increases and the defrosting time can be shortened.
Further, when the drain outlet 20 is opened at the center of the tray 19, the bottom surface of the tray 19 is sharpened downward and the drain is collected at the center. Therefore, as shown in FIG. If the butterfly shape or the figure 8 shape is formed along the corner of the tray 19, it becomes easy to install the pipe on the tray 19. In addition, water droplets can easily flow to the drain port 20.

  Since other configurations and operations are the same as those in the first embodiment, the description thereof is omitted.

Embodiment 3 FIG.
In the first and second embodiments, a case where the bypass circuit 9 enters the evaporator 5 via the tray pipe 8 is shown. However, in the third embodiment, a circuit for flowing hot gas directly to the evaporator 5 is also provided. is there.
FIG. 15 shows a refrigerant circuit according to the third embodiment. The bypass circuit 9 from the three-way valve 2 branches in two, and the first bypass circuit 9a directly enters the evaporator 5 from the first throttle means 7a, and the second And a second bypass circuit 9b (corresponding to the bypass circuit 9 in the first and second embodiments) that continues to the evaporator 5 through the tray pipe 8 from the throttle means 7b.

FIG. 16 is a rear view of the refrigerator-freezer, and the bypass circuit 9 (first and second bypass circuits 9a and 9b) passes through the inside of the heat insulating wall 16 on the rear surface of the refrigerator after exiting the three-way valve 2, and is a hole at the inlet of the cooling chamber. Enter the warehouse from 18.
FIG. 17 is a view of the cooling chamber 17 of the refrigerator-freezer of FIG. 16 as viewed from the front side of the door. The evaporator 5 is disposed at the center of the cooling chamber 17, and the tray 19 is provided below the evaporator 5. One of the bypass circuits 9 (first bypass circuit 9 a) entering from the cooling chamber inlet hole 18 is directly connected to the inlet of the evaporator 5, and the other (second bypass circuit 9 b) extends along the tray 19. Accordingly, it is connected to the inlet of the evaporator 5.
Other configurations are the same as in the case of the first embodiment, and thus description thereof is omitted.

Next, the operation will be described.
As shown in FIG. 15, the refrigerant circuit has two bypass circuits 9, and the hot gas enters the evaporator 5 via the tray pipe 8 (second bypass circuit 9 b) and directly to the evaporator 5. It also has a route (first bypass circuit 9a) through which hot gas flows, and frost is melted by these routes.

The control operation will be described with reference to FIG.
When the defrosting operation is started, the evaporator fan 23 is stopped, the three-way valve 2 is switched so that the discharge gas of the compressor 1 flows from the main circuit 6 to the bypass circuit 9, and the second throttle on the evaporator 5 side is switched. After the means 7b is closed, the compressor frequency is changed to the defrosting frequency α (STEP 1). In general, since the compressor is operated at a lower frequency during normal operation, the defrosting frequency α is higher than the frequency during normal operation. The defrosting time can be shortened by setting the value as large as possible in consideration of the current value limitation and the liquid back reliability to the compressor 1. When the three-way valve 2 is switched to the bypass circuit 9, the high and low pressures approach a pressure equalization state, so that the refrigerant suddenly flows into the bypass circuit 9 and a refrigerant sound is generated. Therefore, before switching the three-way valve 2 to the bypass circuit 9, The compressor frequency may be reduced or the compressor 1 may be stopped. At this time, if the compressor 1 is stopped, it is necessary to secure time until restart for reliability, and it takes time for defrosting. Therefore, the compressor frequency is reduced to the minimum rotation speed. More preferred.

  Next, when the temperature of the evaporator 5 reaches Te ° C., the first throttle means 7a is closed, the second throttle means 7b is opened, and the compressor frequency β is changed (STEP 2). The compressor frequency β takes a value necessary for melting the frost that has fallen on the tray 19, but if the frequency is high, the evaporator 5 is overheated, and thus a value smaller than the frequency α is desirable. Te ° C. is a value equal to or higher than 0 ° C., and is a temperature set to ensure defrosting of the evaporator 5. Further, when the tray temperature becomes equal to or higher than Tt ° C., the three-way valve 2 is switched from the bypass circuit 9 to the main circuit 6, the first throttle means 7a is opened, and the compressor frequency γ is changed (STEP 3). The compressor frequency γ is a value set for cooling the evaporator 5, and is set to a value larger than the compressor frequency β in order to cool it as soon as possible. At this time, since the evaporator fan 23 is stopped, the compressor frequency γ may be set to a large value so that the low pressure does not decrease too much. Tt ° C. is a value equal to or higher than 0 ° C., and is a temperature set to reliably melt the frost on the tray. Further, when the temperature of the evaporator 5 becomes equal to or lower than the predetermined temperature, the defrosting operation is terminated, and the evaporator fan 23 is operated to shift to the normal operation (STEP 4). The operation after STEP 3 is a time provided for cooling the evaporator 5, and the defrosting operation may be terminated after a predetermined time regardless of the temperature of the evaporator 5.

Embodiment 4 FIG.
FIG. 19 is a rear view of the refrigerator-freezer according to Embodiment 4 of the present invention, and FIG. 20 is a view of the cooling chamber 17 of the refrigerator-freezer of FIG.
In FIG. 19, the bypass circuit 9 is divided into two branches, one (second bypass circuit 9b) passes through the drain hose 21 and enters the cooling chamber 17 from the drain port 20, and the other (first bypass circuit 9a) It passes through the inside of the heat insulating wall 16 on the back of the refrigerator and enters the cooling chamber 17 from the hole 18 at the cooling chamber entrance.
Further, in FIG. 20, the evaporator 5 is disposed in the center of the cooling chamber 17, and a tray 19 is provided below the evaporator 5, and one of the bypass circuits 9 entered from the drain port 20 (the second (second)). The bypass circuit 9b) is connected to the inlet of the evaporator 5 along the tray 19, and one of the bypass circuits 9 (the first bypass circuit 9a) entering from the hole 18 at the cooling chamber inlet is connected to the inlet of the evaporator 5. Connected directly.
Other configurations and operations are the same as in the case of the third embodiment, and a description thereof will be omitted.

Embodiment 5 FIG.
In the first to fourth embodiments, the drain 19 is provided at the center of the tray 19 and the tray 19 is convex downward toward the center. However, in the fifth embodiment, the tray 19 is planar.
FIG. 21 is a view of the cooling chamber 17 of the refrigerator-freezer according to Embodiment 5 as viewed from the front side of the door. The floor surface of the tray 19 is inclined obliquely so that the left rear surface is the lowest. When the tray pipe 8 is bent as shown in FIGS. 5 to 7 and FIGS. 12 to 14, the arrangement of the tray 19 is easy if the floor surface is flat. In FIG. 21, the bypass circuit 9 (first and second bypass circuits 9a and 9b) is introduced into the chamber through the hole 18 at the cooling chamber inlet, but from the drain port 20 into the chamber as in the second embodiment. The configuration of the bypass circuit 9 can also be applied to either FIG. 1 or FIG. The tilt of the tray 19 is not limited to the left rear surface, and the tray 19 can be tilted so that one corner on the left and right sides is lowest.
Other configurations and operations are the same as in the case of the third embodiment, and a description thereof will be omitted.

Embodiment 6 FIG.
In the first to fifth embodiments, the tray pipe 8 is provided on the tray 19, but in the sixth embodiment, the tray pipe 8 is provided along the lower surface of the tray 19.
FIG. 22 is a view of the cooling chamber 17 of the refrigerator-freezer according to the fifth embodiment when viewed from the front side of the door. A tray pipe 8 is provided along the lower surface of the tray 19, and the tray pipe 8 is brought into contact with the tray 19. When the tray 19 is made of aluminum, the heat conductivity is high and the defrosting efficiency is increased. The tray pipe 8 may be installed outside the drain port 20 and along the drain hose 21. The drain hose 21 may be bent from the positional relationship with the drain pan 13 or may have a structure in which a water reservoir is formed by meandering up and down in order to prevent air flow. It may be difficult to install in the cooling chamber 17. For this reason, by arranging the tray piping 8 along the outside of the drain hose 21, the shape of the drain hose 21 becomes free, and the production efficiency is good.
Other configurations and operations are the same as in the case of the third embodiment, and a description thereof will be omitted.

  1 compressor, 2 three-way valve, 3 condenser, 4 capillary tube, 5 evaporator, 6 main circuit, 7 throttle means, 7a first throttle means, 7b second throttle means, 8 tray piping, 9 bypass circuit, 9a 1st bypass circuit, 9b 2nd bypass circuit, 10 machine room, 11 machine room fan (fan for compressor cooling), 13 drain pan, 14 dryer, 15 steel plate, 16 heat insulation wall, 17 cooling room, 18 cooling room Inlet hole, 19 tray, 20 drain, 22 suction pipe, 23 evaporator fan.

Claims (12)

The refrigeration cycle includes a main circuit configured in the order of a compressor, a three-way valve, a condenser, a capillary tube, an evaporator, and a suction pipe, and a bypass circuit that branches at the three-way valve and leads to a tray pipe and an evaporator inlet. Prepared,
It has a cooling chamber on the back side in the cabinet, the cooling chamber is provided with the evaporator, an evaporator fan and a tray, and a tray pipe is provided along the tray.
The defrosting operation of the refrigeration cycle consists of an evaporator defrosting section, a tray defrosting section, and an evaporator cooling section,
In the evaporator defrosting section, the evaporator fan is stopped, the frequency of the compressor is reduced to the minimum number of rotations, the three-way valve is switched to the bypass circuit, and the compressor has a higher frequency than during normal operation. Drive on,
In the tray defrosting section, the compressor is operated at a frequency lower than a predetermined frequency of the evaporator defrosting section,
In the evaporator cooling section, after switching the three-way valve to the main circuit, the compressor is operated at a frequency higher than the frequency of the tray defrosting section,
A refrigerator-freezer , wherein the evaporator fan is operated at the end of the defrosting operation . Provided a machine room in the refrigerator, according to claim 1 and a fan for compressor cooling and the compressor in the machine room, Joshimochu is characterized in that to or stop lowering the rotating speed of the fan serial mounting of the refrigerator. The inner wall of the cooling chamber is provided with a hole through which the evaporator pipe enters the cooling chamber, the three-way valve is disposed in a machine room provided on the lower back side of the inside of the cabinet, and the bypass circuit exits the three-way valve. 3. The refrigerator-freezer according to claim 1, wherein after passing through the inside of the heat insulating wall on the back of the inside of the refrigerator, the refrigerator enters the refrigerator through a hole at the inlet of the cooling chamber. Refrigerator according to claim 1 to 3 floor of the tray, characterized in that a as the vicinity of the central portion becomes the lowest drainage port in the vicinity of the central portion. According to any one of claims 1 to 3, characterized in that the end portion of the floor surface in the flat floor surface of the tray is inclined so that the lowest, provided drainage openings in the vicinity of the end portion Freezer refrigerator. 6. The refrigerator-freezer according to claim 5, wherein the floor surface of the tray is inclined to one of the left and right sides, is inclined from the front side to the back side, and the drain outlet is provided in the vicinity of the lowest end. . The refrigerator-freezer according to any one of claims 4 to 6 , wherein the tray pipe is provided along an upper surface of the tray. 8. The refrigerator-freezer according to claim 7, wherein the tray pipe is provided along the circumference of the drain outlet on the upper surface of the tray, or is wound around the circumference. 8. The refrigerator-freezer according to claim 7, wherein the tray pipe passes over the drain outlet on an upper surface of the tray. The tray piping refrigerator according to any one of claims 4-9, characterized in that it is introduced into the cooling chamber through the interior of the drain outlet. The refrigerator tray according to any one of claims 4 to 6 , wherein the tray pipe is introduced into the cooling chamber through an outer periphery of the drain outlet and a lower surface of the tray. Refrigerator according to any one of claims 1 to 11, characterized in that said tray is formed by an aluminum plate or steel plate.

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