JPH07146038A - Refrigerating cycle - Google Patents

Abstract

PURPOSE:To obtain a refrigerating cycle preventing the backflow of liquid to a compressor from an evaporator at the time of defrosting and the backflow of liquid at the time of starting, being excellent in an oil return and increasing the reliability of the compressor. CONSTITUTION:This refrigerating cycle has a construction wherein a refrigerant tank 32 is provided at an inlet part of an evaporator 23 and a second accumulator 25 having a thin pipe 30 for an oil return and a bypass pipe for forming a refrigerant reservoir are provided at an inlet of a compressor, and a refrigerant flowing out from the evaporator 23 at the time of defrosting is made to stay in the refrigerant tank 32 and the second accumulator 25.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating cycle for a refrigerator / freezer which heats and defrosts an evaporator.

[0002]

2. Description of the Related Art In recent years, in a refrigerating cycle of a refrigerating refrigerator that heats and defrosts an evaporator, in order to improve reliability of a compressor, a liquid bag at the time of defrosting a heater and a liquid bag at the time of starting the compressor are used. Refrigeration cycles with added accumulators to prevent it are becoming common.

An example of the above-mentioned conventional refrigeration cycle will be described below with reference to the drawings. For example, JP-A-3-
There is a refrigeration cycle as known from Japanese Patent No. 282169.

FIG. 3 shows a conventional refrigeration cycle.
Compressor 1, condenser 2, capillary tube 3
The evaporator 4, the first accumulator 5, the second accumulator 6, and the check valve 7 are sequentially connected to form a refrigeration cycle. Reference numeral 10 is a defrost heater that defrosts the evaporator.

The first accumulator has an inlet 11 on the lower side.
And an outlet 12 is provided on the upper side. The second accumulator has a structure in which an inlet pipe 13 is provided in an upper portion, an oil return hole 14 is provided inside, and an outlet pipe 16 formed in a U-shaped outlet pipe having an outlet 15 is provided in an upper portion. .

In the above structure, when the evaporator 4 is heated by the defrost heater 10 to defrost the evaporator 4, the refrigerant warmed in the evaporator 4 is
The liquid refrigerant flows into the first accumulator 5 and stays in the first accumulator 6 to prevent the liquid refrigerant from flowing into the compressor 1. Further, the second accumulator 6 is configured such that when the compressor 1 is started, the liquid refrigerant overflowed in the first accumulator 5 is compressed by the compressor 1.
It acts to prevent the liquid from backing up and deteriorating the reliability of the compressor 1.

[0007]

However, in the above conventional configuration, when the evaporator 4 is heated by the defrost heater 10, most of the refrigerant warmed in the evaporator 4 flows into the first accumulator 5 and is stored as a liquid refrigerant. Therefore, it is necessary to use a large capacity for the first accumulator 5.

When the compressor 1 is started after the defrosting is finished, the liquid refrigerant in the first accumulator 5 boils and instantly flows into the second accumulator 6, so that the liquid back to the compressor 1 can be prevented. The second accumulator 6 also needed to use a complicated large-sized one having a high gas-liquid separation ability.

When the compressor 1 is stopped during normal operation, most of the refrigerant in the high-voltage circuit such as the condenser 2 flows into the evaporator 4 via the capillary tube 3 and stays as liquid refrigerant. Then, when the compressor 1 is started, the liquid refrigerant in the evaporator 4 instantaneously flows out of the evaporator 4, but since the amount of refrigerant flowing out is very large,
In the accumulator 5 and the second accumulator 6 described above, it is difficult to completely prevent the liquid back to the compressor 1, and the reliability of the compressor 1 is deteriorated.

The present invention solves the above-mentioned conventional problems by eliminating the liquid bag at the time of defrosting the heater and the liquid bag at the end of defrosting and at the time of starting the compressor during normal operation, thereby reducing the size of the accumulator and the compressor. An object is to provide a refrigeration cycle that can improve reliability.

[0011]

To achieve this object, a refrigeration cycle of the present invention comprises a compressor, a condenser, a capillary tube, an evaporator having a defrost heater, a first accumulator, and a second accumulator which are sequentially connected. Then, one is connected to the upper part of the second accumulator and the other is connected to the upper part of the first accumulator, and one is inserted from the lower part of the second accumulator to the upper part of the second accumulator, and Has an oil return hole on the bottom surface of the second accumulator,
A second pipe having a rising portion arranged so that the other is arranged at a position higher than the second accumulator, and connected to the compressor, and an upper portion of the second accumulator and a second pipe.
It has a configuration including a bypass pipe communicating with the pipe rising portion.

Further, one of the second accumulators is inserted from the lower part to the inside of the second accumulator and the other is connected to the compressor. The second pipe is connected downward from the lower part in the second accumulator to the second pipe. It has a structure provided with a thin tube having a predetermined length to be arranged in the.

Further, a refrigerant tank having a predetermined capacity is provided between the evaporator and the capillary tube, the capillary outlet is connected to the upper portion of the refrigerant tank, and the evaporator inlet is connected to the lower portion of the refrigerant tank to remove the refrigerant tank. It is arranged at a position lower than the evaporator temperature in the frost, and has a structure in which a refrigerant tank is embedded in a heat insulating material.

Further, the refrigerant tank is provided with a heat storage material, and the heat storage material is arranged in the heat insulating material at a position lower than the height of the evaporator.

[0015]

According to the present invention, since the liquid refrigerant flowing out from the evaporator can be retained in the second accumulator during defrosting by the above-described structure, liquid back to the compressor during defrosting can be prevented and reliability of the compressor can be improved. You can improve your sex.

Further, when the compressor is started after the defrosting is completed, the liquid refrigerant that has accumulated in the second accumulator and the liquid refrigerant that has accumulated in the evaporator flow only through the narrow tubes, so the liquid back at the time of compressor startup is greatly reduced. can do.

Further, since the refrigerant flowing out of the evaporator at the time of defrosting can be retained in the refrigerant tank arranged between the capillary and the evaporator, the amount of refrigerant flowing out of the evaporator into the second accumulator is greatly reduced. Therefore, the second accumulator can be downsized. Moreover, when the compressor is started, the refrigerant in the evaporator evaporates and is sucked into the compressor as a gas refrigerant, so that liquid backing of the compressor can be prevented.

Further, by providing the heat storage material in the refrigerant tank, the refrigerant flowing into the refrigerant tank can be liquefied reliably, so that the amount of liquid refrigerant retained in the evaporator at the time of defrosting can be greatly reduced, and the compressor It is possible to prevent liquid backing and reduce the starting torque.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.

In FIG. 1, a compressor 20, a condenser 21, a capillary tube 22, and an evaporator 2 are shown.
3, the first accumulator 24, and the second accumulator 25 are sequentially connected to form a refrigeration cycle.

The first accumulator 24 and the second accumulator 25 are connected by a first pipe 26, one of which is connected to the upper part of the first accumulator 24 and the other of which is connected to the upper part of the second accumulator 25. .

Reference numeral 27 is a second pipe connecting the second accumulator 25 and the compressor 20.

The second pipe 27 is connected to the second accumulator 2 from the lower portion 26 of the second accumulator 25.
5 has a rising portion 28 that is inserted to the upper part inside and the other one is arranged at a position higher than the second accumulator 25
The retention part 29 is formed.

Reference numeral 30 denotes a thin pipe for returning the oil of the compressor 20, which is arranged downward in the second pipe 27 from the lower portion 26 of the second accumulator of the second pipe 27 inserted in the second accumulator 2. Are arranged so as to have a predetermined length.

The inner diameter of the thin tube 30 is about 1 mm, and the length thereof is such that the amount of the refrigerant per unit time flowing out from the thin tube 30 to the compressor 20 side when the compressor 20 is started is the amount of the refrigerant per hour which can be evaporated in the second pipe. I have decided to make it less.

Reference numeral 31 is a bypass pipe which connects the inside of the second accumulator 25 and the rising portion 28 of the second pipe 27.

The inner diameter of the bypass pipe 31 is about 1 to 2 mm, which is smaller than the inner diameter of the second pipe of about 6 to 8 mm.

Reference numeral 32 is a refrigerant tank, and the capillary 22 is provided on the upper portion.
The outlet portion 33 of the
Are connected. The refrigerant tank 32 has an internal capacity of about 1/2 to about the amount of refrigerant in the refrigeration cycle.

Reference numeral 35 is a heat insulating material forming the body of the refrigerator-freezer. Reference numeral 36 denotes a defrost heater that defrosts the evaporator 23.

The refrigerant tank 32 is embedded in a heat insulating material 35 which becomes lower than the temperature of the evaporator 23 during defrosting of the evaporator 23.

FIG. 2 illustrates another embodiment, in which the refrigerant tank 32 has a heat insulating material 3 lower than the height of the evaporator 23.
5, the heat storage material 37 is arranged in a heat exchange manner around the refrigerant tank 32.

The melting temperature of the heat storage material 37 is set to 0 ° C. or lower, lower than the temperature of the evaporator 23 during defrosting, and the heat of fusion becomes equal to or more than the heat of condensation of the refrigerant enclosed in the refrigeration cycle. The amount of animal heat storage material is 37.

The operation of the refrigeration cycle configured as described above will be described below. The compressor 20 is repeatedly stopped during normal operation by a control means (not shown). When the compressor 20 operates for a predetermined time, the compressor 20 is stopped and the defrost heater 36 is energized. The heating of the defrost heater 36 raises the temperature of the evaporator 23, and defrosts the frost adhering to the surface of the evaporator 23.

When the temperature of the evaporator 23 rises during the defrosting, the pressure inside the evaporator 23 rises, the refrigerant inside the evaporator 23 flows into the condenser 21 through the capillary tube 22, and the first accumulator 24 flows. Through the second accumulator 25. Second accumulator 25 and second pipe 2
Since the rising portion 28 of 7 is communicated with the bypass pipe 31, the refrigerant is stored in the second accumulator 25.
It is possible to prevent the liquid from being backed up to the compressor 20 during defrosting because the water is accumulated in 9.

When the compressor is started after the defrosting is completed, the retained liquid refrigerant evaporates and becomes a gas state.
It is sucked into the compressor 20 through the pipe 27. At the same time, the liquid refrigerant is also sucked into the thin tube, but since the inner diameter of the tube is much smaller than that of the second pipe 27, the amount of the liquid refrigerant sucked can be reduced.

A refrigerant tank 32 is provided between the inlet portion 34 of the evaporator 23 and the outlet portion 33 of the capillary 22,
Since it is installed at a position lower than the temperature of the evaporator 23 during defrosting, the pressure inside the refrigerant tank 32 becomes lower than the pressure inside the evaporator 23 during defrosting. Therefore, the evaporator 2
Since the refrigerant in 3 can stay in the refrigerant tank 32 side, it is possible to reduce the flow of the liquid refrigerant from the evaporator 23 side to the condenser 21 side through the capillary tube 22 during defrosting, and to the second accumulator 25 side. Since the outflow amount can be reduced, the compressor 20 during defrosting and startup
Liquid back can be prevented.

Further, in the case where the heat storage material is disposed in the refrigerant tank in a heat exchange manner, the heat of fusion of the heat storage material 37 can be utilized, so that the refrigerant flowing into the refrigerant tank 32 can be surely liquefied. The amount of liquid refrigerant retained in the evaporator 23 at the time of defrosting can be significantly reduced, and liquid back at the time of startup and after startup can be prevented.

As described above, the compressor 20 is used in this embodiment.
An evaporator 23 having a condenser 21, a capillary tube 22, a defrost heater 36, a first accumulator 24, and a second accumulator 25 are sequentially connected, one of which is above the second accumulator 25 and the other of which is a second accumulator. First connected to the upper part of the accumulator 24
Pipe 26 and one of the second accumulator lower part 26
Insert it further inside the second accumulator 25,
An oil return hole is provided on the bottom surface of the second accumulator 25 of the insertion section, and a rising section 28 is arranged so that the other is arranged at a position higher than the second accumulator 25. Piping 27 and second
Since the bypass pipe 31 that communicates the upper part of the accumulator 25 with the rising portion 28 of the second pipe 27 is provided, it is important to retain the liquid refrigerant flowing out of the evaporator 23 during defrosting in the second accumulator 25. As a result, it is possible to prevent liquid backing to the compressor 20 during defrosting.

Further, one is inserted from the lower part of the second accumulator 26 to a position above the inside of the second accumulator,
The second pipe 27 from the lower portion 26 in the second accumulator of the second pipe 27 that connects the other side to the compressor 20.
Since the thin pipe 31 having a predetermined length is disposed inside the liquid pipe, the liquid refrigerant flows only through the thin pipe 22 when the compressor 20 is started after the defrosting is completed, so that the liquid back at the time of starting the compressor 20 is greatly increased. Can be reduced to

Evaporator 23 and capillary tube 2
A refrigerant tank 32 having a predetermined capacity is provided between the refrigerant tank 32, a capillary outlet portion 33 is connected to the upper portion of the refrigerant tank 32, and an evaporator inlet portion 34 is connected to the lower portion of the refrigerant tank to prevent the refrigerant tank 32 from being defrosted. Since the refrigerant tank 32 is arranged at a position lower than the evaporator temperature 23 and the refrigerant tank 32 is embedded in the heat insulating material 35, the refrigerant stays in the refrigerant tank 32 during defrosting, so that the liquid bag is reduced during defrosting and after defrosting. It is possible to prevent liquid backing at startup.

Further, the heat storage material 37 is provided in the refrigerant tank 32, and the heat insulating material 3 at a position lower than the height of the evaporator 23 is used.
Since it is arranged in No. 5, since the refrigerant flowing into the refrigerant tank 32 can be liquefied reliably, the amount of liquid refrigerant staying in the evaporator 23 at the time of defrosting can be significantly reduced, and the liquid back of the compressor 20 can be prevented. And the starting torque can be reduced.

[0042]

As described above, according to the present invention, an evaporator having a compressor, a condenser, a capillary tube, and a defrost heater, a first accumulator, and a second accumulator are sequentially connected, and one of the second accumulator is connected. The first pipe connecting the other to the upper part of the first accumulator at the upper part, and the one pipe from the lower part of the second accumulator to the upper part of the inside of the second accumulator, and the oil on the bottom part of the second accumulator at the insertion part. It has a return hole, and the other has a rising part arranged to be arranged at a position higher than the second accumulator, and a second pipe connected to the compressor, an upper part of the second accumulator, and a rising part of the second pipe. Since it is equipped with a bypass pipe that communicates with the parts, the liquid refrigerant flowing out from the evaporator during defrosting Can be made to stay in the second accumulator can be prevented liquid back to the compressor during defrosting.

One of the second accumulators is inserted from the lower part to the upper part of the inside of the second accumulator, and the other part is connected to the compressor. The second pipe is connected downward from the lower part in the second accumulator to the second pipe. By providing the thin tube having a predetermined length, the liquid refrigerant flows only through the thin tube when the compressor is started after defrosting is completed, and therefore the liquid bag at the time of starting the compressor can be significantly reduced.

Further, a refrigerant tank having a predetermined capacity is provided between the evaporator and the capillary tube, the capillary outlet is connected to the upper portion of the refrigerant tank, and the evaporator inlet is connected to the lower portion of the refrigerant tank to remove the refrigerant tank. By arranging it at a position lower than the evaporator temperature in the frost and burying the refrigerant tank in the heat insulating material, the refrigerant stays in the refrigerant tank during defrosting, so the liquid bag decreases during defrosting and when starting after defrosting. It is possible to prevent liquid back-up.

Further, since the heat storage material is provided in the refrigerant tank and is arranged in the heat insulating material at a position lower than the height of the evaporator, the refrigerant flowing into the refrigerant tank can be surely liquefied, so that the inside of the evaporator at the time of defrosting It is possible to greatly reduce the amount of liquid refrigerant retained, and to prevent liquid backing of the compressor and reduce the starting torque.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a refrigeration cycle according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a main part of a refrigeration cycle of another embodiment.

FIG. 3 is a conventional refrigeration cycle block diagram.

[Explanation of symbols]

 20 Compressor 21 Condenser 22 Capillary tube 23 Evaporator 25 Second accumulator 27 Second pipe 30 Fine tube 31 Bypass pipe 32 Refrigerant tank 37 Heat storage material

Claims (4)

[Claims] 1. A compressor, a condenser, a capillary tube, an evaporator having a defrost heater, a first accumulator, and a second accumulator are sequentially connected, one of which is above the second accumulator and the other of which is the first accumulator. A first pipe connecting to the upper part of
One is inserted from the lower part of the second accumulator to above the inside of the second accumulator, and an oil return hole is provided on the bottom surface of the second accumulator of the insertion part, and the other is arranged at a position higher than the second accumulator. A refrigerating cycle comprising: a second pipe connected to the compressor; and a bypass pipe communicating the upper part of the second accumulator with the second pipe rising portion. 2. One of the second accumulators is inserted from a lower part of the second accumulator to an upper part of the inside of the second accumulator, and the other is downward from a lower part of the second pipe of the second pipe connected to the compressor into the second pipe. 2. A thin tube having a predetermined length to be placed in
Refrigeration cycle described. 3. A refrigerant tank having a predetermined capacity is provided between the evaporator and the capillary tube, a capillary outlet is connected to an upper portion of the refrigerant tank, an evaporator inlet is connected to a lower portion of the refrigerant tank, and the refrigerant tank is removed. The refrigerating cycle according to claim 1, wherein the refrigerating cycle is arranged at a position lower than the evaporator temperature in the frost, and the refrigerant tank is embedded in the heat insulating material. 4. The refrigerating cycle according to claim 3, wherein the refrigerant tank is provided with a heat storage material, and the heat storage material is arranged in the heat insulating material at a position lower than the height of the evaporator.