JP2931469B2 - Refrigeration equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration system for cooling a compressor by supplying a refrigerant condensed in a condenser to a low pressure side inside the compressor by a liquid injection circuit.

[0002]

2. Description of the Related Art Conventionally, a refrigerant having a low specific heat ratio such as R-12 has been used in a refrigerant circuit constituting a refrigerating apparatus such as a low-temperature showcase installed as a food freezing / refrigeration facility in a supermarket or the like. In a refrigeration system using such a refrigerant, the discharge temperature of the refrigerant is relatively low, so that the temperature rise of the compressor is not a problem. However, in recent years, a specific refrigerant (R-12, etc.) related to the problem of destruction of the ozone layer surrounding the global environment. Is becoming unusable.

Therefore, in recent years, R-22 has been used as an alternative refrigerant.
For example, a refrigerant having a low risk of destruction of the ozone layer has been used. However, R-22 is R-12
As a result, there is a problem that the specific heat ratio is large, the discharge temperature of the refrigerant rises, the temperature of the compressor rises abnormally, and the windings of the drive motor burn out.

To solve this problem, a so-called liquid injection system has been conventionally considered as a means for lowering the temperature of the compressor. In the liquid injection method, the refrigerant discharged from the compressor is condensed and liquefied, and a part of the condensed liquid refrigerant is returned to the low pressure side of the compressor via a capillary tube by a liquid injection circuit, and is evaporated inside the compressor. It cools the compressor.

FIG. 6 shows a refrigerant circuit of a conventional refrigeration system having such a liquid injection circuit. Discharge side pipe 2 of so-called rotary type compressor 1
The condenser 3 is connected to the outlet, and an outlet pipe 4 of the condenser 3 is inserted into the receiver tank 5 from the bottom of the receiver tank 5 and opened at the upper part. From the bottom surface of the receiver tank 5, an inlet pipe 7 of a liquid injection circuit 6 and a pipe 9 connected to an expansion valve 8 are inserted, and open below the outlet pipe 4. The liquid injection circuit 6 includes a capillary tube 10, and an outlet pipe 11 thereof is connected to the compressor 1.
Is connected to the low pressure side. The outlet side of the expansion valve 8 is connected to the inlet pipe 13 of the evaporator 12, and the outlet pipe 14 of the evaporator 12 is connected to the accumulator 15. The accumulator 15 is connected to the compressor 1 via a check valve 16.
Is connected to the suction side pipe 17.

In this configuration, a predetermined amount of R-22 refrigerant is sealed in the refrigerant circuit, and the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 flows into the condenser 3 from the discharge-side pipe 2, And is cooled and condensed by air cooling or water cooling. The liquid refrigerant condensed in the condenser 3 is supplied to the outlet pipe 4
Through the receiver tank 5 and is stored therein at a predetermined liquid level.

The inlet side pipe 7 and the pipe 9 of the liquid injection circuit 6 are configured so as to open below the refrigerant level in the receiver tank 5 in a normal state, whereby both pipes 7 and 9 are connected. , A liquid refrigerant flows in. Inlet piping 7 of liquid injection circuit 6
The liquid refrigerant flowing into the compressor is depressurized by the capillary tube 10 and is then sucked from the outlet pipe 11 to the low pressure side of the compressor 1, where it is evaporated to cool the compressor 1. This prevents damage caused by a rise in the temperature of the compressor 1 when the R-22 refrigerant is used. The liquid refrigerant flowing into the pipe 9 is decompressed by the expansion valve 8 and then flows into the evaporator 12 through the inlet pipe 13 to evaporate, thereby cooling the inside of a refrigerator such as a showcase (not shown). The refrigerant flowing out of the evaporator 12 returns to the compressor 1 from the suction side pipe 17 via the accumulator 15 and the check valve 16.

[0008]

In such a conventional refrigeration system, for example, the refrigerant in the circuit runs short due to leakage of the refrigerant, or the condensing capacity of the condenser 3 decreases due to the clogging of the condenser 3 with dust. When an abnormal state such as the above occurs, a flash gas is generated in the refrigerant that has exited the condenser 3, the refrigerant level in the receiver tank 5 is reduced, and finally the liquid flows into both the inlet-side pipe 7 and the pipe 9. The refrigerant mixed with the gas flows in.

Here, since the pipe 9 passes through the interior of the showcase or the like which has been cooled down to the expansion valve 8, the refrigerant passing therethrough is slightly supercooled and condensed, but the liquid injection is performed. In circuit 6, such supercooling cannot be expected. Therefore, when the amount of gas refrigerant flowing into the inlet pipe 7 increases, the amount of liquid refrigerant that is decompressed by the capillary tube 10 and evaporates in the compressor 1 decreases, and the cooling capacity of the compressor 1 decreases, and the compressor 1 malfunctions. There is a problem that high temperatures cause damage. Further, exerting the cooling capacity in the evaporator 12 in such an abnormal state also causes an excessive load on the compressor 1, which is not preferable.

The present invention has been made to solve the above-mentioned conventional technical problem, and has as its object to provide a refrigeration apparatus that can preferentially cool a compressor even when an abnormal condition occurs. And

[0011]

A refrigerating apparatus R according to the present invention comprises a compressor 1, a condenser 3 connected to a discharge side of the compressor 1, an outlet of the condenser 3, and a compressor. An evaporator 12 connected to the suction side of the compressor 1 and a liquid injection circuit 6 for reducing the pressure of the refrigerant flowing out of the condenser 3 and supplying the decompressed refrigerant to a low-pressure side inside the compressor 1. A branch (branch pipe) 20 for diverting the refrigerant discharged from the condenser 3 and supplying it to the evaporator 12 and the liquid injection circuit 6
Configure, the outlet 20B of the liquid injection circuit 6 in the branch portion (branch pipe) 20, the branch portion
(Branch pipe) provided in the direction in which the refrigerant flows into 20;
Outlet 20 to evaporator 12 at branching section (branch pipe) 20
C is provided by branching in the horizontal direction .

The refrigeration apparatus R according to the second aspect of the present invention has
The branching section has a single inlet 20A and two outlets 20B,
20C and a substantially T-shaped branch pipe 20 provided with
The straight ahead from the entrance 20A of the branch pipe 20
Outlet 20B for the liquid injection circuit 6
Evaporated from the entrance 20A to a position bent horizontally
An outlet 20C for the vessel 12 is provided.

[0013]

According to the refrigerating apparatus R of the first aspect, the refrigerant flowing out of the condenser 3 is divided into a refrigerant flowing toward the liquid injection circuit 6 and a refrigerant flowing toward the evaporator 12 at the branch section (branch pipe) 20. When a flash gas is generated in the refrigerant that has exited the condenser 3, the refrigerant in which the liquid and the gas are mixed flows into the branch portion (branch pipe) 20, but the liquid refrigerant therein has a higher specific gravity than the gas, so that the inertia increases. Since the force is large and the vehicle tries to go straight, the refrigerant easily flows into the outlet 20B to the liquid injection circuit 6 provided in the direction in which the refrigerant flows . As a result, the liquid refrigerant is supplied to the liquid injection circuit 6 preferentially. Meanwhile, evaporation
Since the outlet to the vessel 12 is provided by being branched in the horizontal direction,
Liquid refrigerant completely in the liquid injection circuit 6 direction
Will not be separated, even when flash gas is generated
The cooling capacity of the evaporator 12 can be ensured.

According to the refrigeration apparatus R according to claim 2, pressurized to the
In addition, a branch is formed by a single inlet 20A and two outlets 20B,
20C and a substantially T-shaped branch pipe 20 provided with
At a position straight ahead from the entrance 20A of the branch pipe 20,
An outlet 20B for the feed injection circuit 6 is provided, and the
A position for the evaporator 12 at a position bent horizontally from the port 20A.
The structure is simplified by providing the outlet 20C.
When it becomes possible to reduce costs and save space
In both cases, the degree of freedom in design also increases.

[0015]

Next, an embodiment will be described with reference to the drawings. FIG.
FIG. 2 is a refrigerant circuit diagram of the refrigeration apparatus R of the present invention, and FIG.
FIG. 4 is an enlarged perspective view of a branch pipe 20 as a branch portion of FIG.
In each of the drawings, components denoted by the same reference numerals as those in FIG. 6 have the same functions. In FIG. 1, a condenser 3 is connected to a discharge side pipe 2 of a rotary type compressor 1,
The outlet pipe 4 of the condenser 3 is inserted into the receiver tank 5 from the bottom of the receiver tank 5 as in the case of FIG.
It is open at the top. The outlet pipe 21 of the receiver tank 5 is inserted from the bottom surface of the receiver tank 5, and is opened below the outlet pipe 4. As shown in FIG.
The inlet 20A of the substantially T-shaped branch pipe 20 is connected as shown in FIG.

As shown in FIG. 2, the branch pipe 20 has an inlet 2
An outlet 20B for a liquid injection circuit that opens at a position straight ahead from 0A, and an outlet 2 for an evaporator that opens at a position bent at a right angle in the horizontal direction from the inlet 20A.
It is arranged to have 0C. The outlet 20B is connected to the inlet pipe 7 of the liquid injection circuit 6, and the outlet 20C is connected to the pipe 9 to the expansion valve 8.

The liquid injection circuit 6 similarly includes a capillary tube 10 and an outlet pipe 11 thereof.
Is connected to the low pressure side of the compressor 1. The expansion valve 8
Is connected to an inlet pipe 13 of an evaporator 12 provided in a cool air passage such as a showcase (not shown), and an outlet pipe 14 of the evaporator 12 is connected to an accumulator 15. The accumulator 15 is connected to a suction side pipe 17 of the compressor 1 via a check valve 16.

In the above configuration, a predetermined amount of R-22 refrigerant is sealed in the refrigerant circuit, and in a normal state, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 is discharged from the discharge side pipe 2 to the condenser. 3, where it is cooled by air cooling or water cooling to be condensed and liquefied. The liquid refrigerant condensed in the condenser 3 flows into the receiver tank 5 through the outlet pipe 4 and is stored therein at a predetermined liquid level.

Outlet pipe 21 of the receiver tank 5
Is configured to open below the refrigerant level in the receiver tank 5 in a normal state, whereby the liquid refrigerant flows into the pipe 21 and flows into the branch pipe 20 from the inlet 20A. The liquid refrigerant that has flowed into the branch pipe 20 proceeds straight as it is toward the outlet 20B due to inertial force, but is partially bent toward the outlet 20C due to friction with the pipe inner wall. As a result, the liquid refrigerant that has flowed into the branch pipe 20 is split at a predetermined ratio in the directions of the outlet 20B and the outlet 20C.

The liquid refrigerant flowing out of the outlet 20B flows into the inlet pipe 7 of the liquid injection circuit 6, is decompressed by the capillary tube 10, and is sucked from the outlet pipe 11 to the low pressure side of the compressor 1, where it is drawn there. Evaporate and compressor 1
To cool. This prevents damage caused by a rise in the temperature of the compressor 1 when the R-22 refrigerant is used. On the other hand, the liquid refrigerant flowing out from the outlet 20C flows into the pipe 9 and is decompressed by the expansion valve 8, and then the evaporator 12
And evaporates. This cools the inside of the refrigerator such as a showcase (not shown). The low-temperature refrigerant that has left the evaporator 12 returns to the compressor 1 from the suction-side pipe 17 via the accumulator 15 and the check valve 16.

Next, the refrigeration apparatus R may be in a state where the refrigerant in the circuit becomes insufficient due to leakage of the refrigerant, for example.
If the condensing capacity of the condenser 3 is reduced due to clogging with dust or the like, a flash gas is generated in the refrigerant flowing out of the condenser 3 and the liquid level of the refrigerant in the receiver tank 5 decreases. Eventually, when the liquid level of the receiver tank 5 drops below the height at which the outlet pipe 21 opens, the refrigerant containing the liquid and the gas flows into the outlet pipe 21.

Here, the liquid refrigerant of the gas-liquid mixed refrigerant flowing into the branch pipe 20 has a higher density and a larger mass than the gas refrigerant. Therefore, a large amount of force is required to change the direction of movement due to an increase in inertial force as compared with a gas refrigerant. Therefore, the liquid refrigerant that has flowed into the branch pipe 20 easily travels straight, and flows straight from the inlet 20A in the direction in which most of the liquid refrigerant flows to the outlet 20A for the liquid injection circuit.
B, and a part thereof is bent by friction with the inner wall of the pipe, and flows out from the evaporator outlet 20C.

On the other hand, the gas refrigerant flowing into the branch pipe 20 has a small mass and a small inertia force. In addition, since it has low viscosity, it is easily bent and heads toward the outlet 20C. As a result, looking at the state of the refrigerant diverted in the branch pipe 20, the state toward the outlet 20B is in a state with a large amount of liquid and a small amount of gas, and the state toward the outlet 20C is in a state with a small amount of liquid and a large amount of gas. . Therefore, even in the abnormal state where the flash gas is generated, the liquid refrigerant is preferentially supplied to the liquid injection circuit 6, and the cooling of the compressor 1 can be ensured. Although a refrigerant having a large amount of gas is supplied to the pipe 9, the refrigerant is in an abnormal state, and is somewhat supercooled before reaching the expansion valve 8 as described above. . In particular, since the liquid refrigerant is diverted in the horizontal direction, the liquid refrigerant is hardly affected by gravity. Therefore, in a normal state, the liquid refrigerant flows excessively through the liquid injection circuit 6 and the inconvenience such that the liquid refrigerant cannot be supplied to the evaporator 14 is avoided. Easier to do.

Here, in addition to the structure shown in FIG. 2, the structure shown in FIGS. 3 to 5 can be considered as the branch flow of the refrigerant in the branch pipe 20. In each of the drawings, the portions indicated by the same reference numerals as those in FIGS. 1 and 2 are assumed to have the same function.
The branch pipe 20 shown in FIG. 3 is bent downward from an inlet 20A connected to the outlet pipe 21, and proceeds downward as it is to form an outlet 20B for a liquid injection circuit at an end bent in the horizontal direction. An outlet 20C for an evaporator is formed at an end branched horizontally from a vertically descending portion at an upper portion.

In the case of the branch pipe 20 shown in FIG. 3, the refrigerant flowing into the inlet 20A is bent downward in the flowing direction along the pipe shape, and the straight-ahead refrigerant flows toward the outlet 20B.
The one bent in the middle goes to the outlet 20C. Therefore, when the gas-liquid mixed refrigerant flows in from the inlet 20A, the liquid refrigerant has a large mass as described above, so that it tends to proceed downward due to inertial force and gravity, and the gas refrigerant is easily bent from the middle due to its small mass. Become like Therefore, similarly, the refrigerant exiting from the outlet 20B is a refrigerant having a large amount of liquid and a small amount of gas, and the refrigerant exiting from the exit 20C is a refrigerant having a large amount of gas and a small amount of liquid. Therefore, the supply of the liquid refrigerant to the liquid injection circuit 6 may be prioritized. become able to.

The branch pipe 20 shown in FIG. 4 has an inlet 20A connected to the outlet-side pipe 21 and has an upper and lower branch. The end of the upwardly branched pipe has an evaporator outlet 20C.
However, an outlet 20B for a liquid injection circuit is formed at the end of the pipe branched downward.

In the case of the branch pipe 20 shown in FIG. 4, the refrigerant flowing into the inlet 20A collides with the pipe wall at the branch point, and the one having a large mass flows to the lower outlet 20B due to gravity and the one having a small mass flows to the upper outlet 20C. Will be headed to. Therefore, when the gas-liquid mixed refrigerant flows in from the inlet 20A, the liquid refrigerant has a large mass and thus easily moves downward due to gravity, and the gas refrigerant has a small mass and moves upward. Therefore, similarly, the refrigerant exiting from the outlet 20B is a refrigerant having a large amount of liquid and a small amount of gas, and the refrigerant exiting from the exit 20C is a refrigerant having a large amount of gas and a small amount of liquid. Therefore, the supply of the liquid refrigerant to the liquid injection circuit 6 may be prioritized. become able to.

Further, the branch pipe 20 shown in FIG. 5 is provided with an outlet 20 for a liquid injection circuit at an end which proceeds straight from an inlet 20A connected to the outlet side pipe 21 as it is.
B is formed, and an outlet 20C for an evaporator is formed at an end of a pipe branched upward in the middle.

In the case of the branch pipe 20 shown in FIG. 5, of the refrigerant flowing into the inlet 20A, the one that has gone straight on goes to the outlet 20B, and the one that is bent upward on the way goes to the outlet 20C. Accordingly, when the gas-liquid mixed refrigerant flows in from the inlet 20A, the liquid refrigerant has a large mass as described above, so that it is easy to move forward due to inertial force, and the gas refrigerant has a small mass, so that it is easy to rise, and from the middle upward. It can be easily bent. Therefore, the refrigerant flowing out of the outlet 20B is a refrigerant having a large amount of liquid and a small amount of gas, and
The refrigerant discharged from the refrigerant becomes a refrigerant having a large amount of gas and a small amount of liquid, so that the supply of the liquid refrigerant to the liquid injection circuit 6 can be prioritized.

[0030]

According to the first aspect of the present invention, the refrigerant that has exited the condenser is divided at the branching portion into one that goes to the liquid injection circuit and one that goes to the evaporator. Cool the branch
Since the medium is provided in the direction in which the medium flows , even in an abnormal state in which flash gas is generated in the refrigerant that has exited the condenser, the liquid refrigerant easily flows into the liquid injection circuit as it is due to inertial force. Therefore, the liquid refrigerant is preferentially supplied to the liquid injection circuit, so that the cooling of the compressor is ensured and the durability of the compressor is improved. On the other hand,
Since the outlet to the evaporator is provided branched in the horizontal direction,
Liquid refrigerant is completely separated in the liquid injection circuit direction.
Evaporator even when flash gas is generated
Cooling capacity can be secured.

According to the invention of claim 2, in addition to the above,
The fork is a roughly T-shaped segment with a single inlet and two outlets.
Constructed of a branch pipe, proceeding straight from the entrance of the branch pipe
An outlet for a liquid injection circuit is provided at the position,
An outlet for the evaporator is installed at a position bent horizontally from the inlet.
Simplifies the structure and reduces costs
And space saving, and freedom of design
The degree also increases.

[Brief description of the drawings]

FIG. 1 is a refrigerant circuit diagram of a refrigeration apparatus of the present invention.

FIG. 2 is an enlarged perspective view of a refrigerating device in a branch pipe portion.

FIG. 3 is a perspective view of a branch pipe having another shape.

FIG. 4 is a perspective view of another shape of a branch pipe.

FIG. 5 is a perspective view of still another shape of the branch pipe.

FIG. 6 is a refrigerant circuit diagram of a conventional refrigeration apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 3 Condenser 6 Liquid injection circuit 12 Evaporator 20 Branch pipe 20B Exit for liquid injection circuit 20C Exit for evaporator

Claims (2)

(57) [Claims] 1. A compressor, a condenser connected to a discharge side of the compressor, an evaporator connected between an outlet side of the condenser and a suction side of the compressor, and the condenser. Refrigeration system equipped with a liquid injection circuit for reducing the pressure of the refrigerant discharged from the compressor and supplying it to the low-pressure side inside the compressor, diverting the refrigerant discharged from the condenser and supplying the divided refrigerant to the evaporator and the liquid injection circuit a branch unit that constitutes the,
An outlet to the liquid injection circuit in the branch portion is provided in a direction in which the refrigerant flows into the branch portion.
In both cases, the outlet to the evaporator at the branch is
A refrigeration apparatus characterized by being provided in a branch . 2. The branch has a single inlet and two outlets.
And a substantially T-shaped branch pipe.
Liquid injector at a position straight ahead from the entrance
An outlet for the installation circuit is provided,
It is noted that an outlet for the evaporator is
The refrigeration apparatus of claim 1, wherein