JPH05215413A - Freezer - Google Patents

Abstract

PURPOSE:To obtain a freezer which can cool a compressor with priority even when the freezer is in trouble. CONSTITUTION:A condenser 3 is connected to a discharge side of a compressor 1. An evaporator 12 is interposed between an output side of the condenser 3 and an inlet side of the compressor 1. A liquid injection circuit 6 is provided to supply refrigerant from the condenser 3, after reducing its pressure, to a low pressure side inside the compressor 1. A branched tube 20 is provided to divide the refrigerant from the condenser 3 to supply it to the evaporator 12 and the liquid injection circuit 6. An outlet 20B of the branched tube 20 to the liquid injection circuit 6 is provided in the flowing direction of the refrigerant, which flows into the branched tube 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating apparatus 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 which constitutes a refrigerating device such as a low temperature showcase installed as a food freezing / refrigerating facility in a supermarket or the like. Since the discharge temperature of the refrigerant is relatively low in the refrigerating apparatus using such a refrigerant, the rise in the temperature of the compressor does not pose a problem, but the specified refrigerant (R-12 etc.) related to the problem of ozone layer depletion surrounding the global environment in recent years. Is becoming unusable.

Therefore, in recent years, R-22 has been used as an alternative refrigerant.
Refrigerants having a low risk of depleting the ozone layer have come to be used. However, R-22 is R-12
Has a larger specific heat ratio than that of the above, the discharge temperature of the refrigerant rises, the temperature of the compressor rises abnormally, and the winding of the drive motor burns out.

In order to solve this, a so-called liquid injection system has been conventionally considered as a means for lowering the temperature of the compressor. The liquid injection method condenses and liquefies the refrigerant discharged from the compressor, returns a part of the condensed liquid refrigerant to the low pressure side of the compressor via the capillary tube by the liquid injection circuit, and evaporates it inside the compressor. It cools the compressor.

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

In such a structure, a predetermined amount of R-22 refrigerant is enclosed 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, Is cooled by air cooling or water cooling method and condensed. The liquid refrigerant condensed in the condenser 3 is the outlet side pipe 4
Through it to the receiver tank 5 where it is stored at a predetermined liquid level.

The inlet side pipe 7 and the pipe 9 of the liquid injection circuit 6 are constructed so as to open below the liquid level of the refrigerant in the receiver tank 5 in a normal state, whereby both pipes 7 and 9 are opened. The liquid refrigerant flows in. Inlet side pipe 7 of the liquid injection circuit 6
After being decompressed by the capillary tube 10, the liquid refrigerant that has flown into is sucked from the outlet side pipe 11 to the low pressure side of the compressor 1 and evaporated there to cool the compressor 1. This prevents the occurrence of damage due to the temperature rise of the compressor 1 when the R-22 refrigerant is used. The liquid refrigerant that has flowed 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 storage such as a showcase (not shown). The refrigerant discharged from the evaporator 12 is returned to the compressor 1 through the suction side pipe 17 via the accumulator 15 and the check valve 16.

[0008]

In the conventional refrigeration system, the condenser capacity of the condenser 3 is lowered due to a shortage of the refrigerant in the circuit due to leakage of the refrigerant or clogging of the condenser 3 with dust. When an abnormal state such as that occurs, flash gas is generated in the refrigerant that has exited the condenser 3, the refrigerant liquid level in the receiver tank 5 is lowered, and finally liquid is stored in both the inlet side pipe 7 and the pipe 9. The refrigerant mixed with gas comes to flow in.

Here, since the pipe 9 passes through the interior of the showcase or the like that is cooled by the time it reaches the expansion valve 8, the refrigerant passing therethrough is somewhat supercooled and condensed, but liquid injection is performed. In the circuit 6, such supercooling cannot be expected. Therefore, when the amount of gas refrigerant flowing into the inlet side pipe 7 increases, the amount of liquid refrigerant that is decompressed by the capillary tube 10 and evaporated in the compressor 1 decreases, the cooling capacity of the compressor 1 decreases, and the compressor 1 malfunctions. There is a problem that the temperature becomes high and damage occurs. Further, it is not preferable to exert the cooling capacity in the evaporator 12 in such an abnormal state, since it causes an excessive load on the compressor 1.

The present invention has been made to solve the above-mentioned conventional technical problems, and an object of the present invention is to provide a refrigeration system capable of preferentially cooling a compressor even when an abnormal state occurs. And

[0011]

A refrigeration system R according to the present invention is a compressor 1, a condenser 3 connected to the discharge side of the compressor 1, an outlet side of the condenser 3 and a compressor. 1 is provided with an evaporator 12 connected to the suction side, and a liquid injection circuit 6 that depressurizes the refrigerant discharged from the condenser 3 and supplies it to the low pressure side inside the compressor 1. A branch portion (branch pipe) 20 that splits the refrigerant discharged from the condenser 3 and supplies the refrigerant to the evaporator 12 and the liquid injection circuit 6.
And the outlet 20B to the liquid injection circuit 6 at the branch portion (branch pipe) 20.
Are provided in the flow direction of the refrigerant flowing into the branch portion (branch pipe) 20.

A refrigerating apparatus R according to a second aspect of the present invention is a compressor 1
A condenser 3 connected to the discharge side of the compressor 1; an evaporator 12 connected between the outlet side of the condenser 3 and the suction side of the compressor 1; And a liquid injection circuit 6 that depressurizes the refrigerant and supplies it to the low-pressure side inside the compressor 1. The refrigerant that has flowed out of the condenser 3 is branched and supplied to the evaporator 12 and the liquid injection circuit 6. A branch portion (branch pipe) 20 is formed, and the outlet 20B to the liquid injection circuit 6 in the branch portion (branch pipe) 20 is connected to the evaporator 1
It is provided below the exit 20C heading toward 2.

[0013]

According to the refrigerating apparatus R of the first aspect, the refrigerant discharged from the condenser 3 is divided into the one directed to the liquid injection circuit 6 and the one directed to the evaporator 12 in the branch portion (branch pipe) 20. When flash gas is generated in the refrigerant exiting the condenser 3, the refrigerant in which the liquid and the gas are mixed flows into the branch portion (branch pipe) 20, but since the liquid refrigerant therein has a larger specific gravity than the gas refrigerant. Since the inertial force is large and tries to go straight as it is, the outlet 20 to the liquid injection circuit 6 provided in the flowing direction of the inflowing refrigerant.
It becomes easy to flow into B. Thereby, the liquid refrigerant is preferentially supplied to the liquid injection circuit 6.

According to the refrigeration system R of claim 2, the condenser 3
The refrigerant that has exited is divided into a refrigerant directed to the liquid injection circuit 6 and a refrigerant directed to the evaporator 12 at a branch (branch) 20. When flash gas is generated in the refrigerant exiting the condenser 3, the refrigerant in which the liquid and the gas are mixed flows into the branch portion (branch pipe) 20, but since the liquid refrigerant therein has a larger specific gravity than the gas refrigerant. Gravity facilitates the flow into the outlet 20B to the liquid injection circuit 6 provided on the lower side. Thereby, the liquid refrigerant is preferentially supplied to the liquid injection circuit 6.

[0015]

Embodiments Next, embodiments will be described with reference to the drawings. Figure 1
Is a refrigerant circuit diagram of the refrigerating apparatus R of the present invention, and FIG.
It is an expansion perspective view of the branch pipe 20 part as a branch part of.
In each drawing, 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 side pipe 4 of the condenser 3 is inserted from the bottom surface of the receiver tank 5 into the receiver tank 5 as in the case of FIG.
It opens at the top. An outlet side pipe 21 of the receiver tank 5 is inserted from the bottom surface of the receiver tank 5 and opens below the outlet side pipe 4. The outlet side pipe 21 of the receiver tank 5 is shown in FIG.
An inlet 20A of the branch pipe 20 having a substantially T shape as shown in FIG.

This branch pipe 20 has an inlet 2 as shown in FIG.
The outlet 20B for the liquid injection circuit that opens straight from 0A, and the outlet 2 for the evaporator that opens at a position that is bent at a right angle from the inlet 20A in the horizontal direction.
It is arranged to have 0C. The outlet 20B is connected to the inlet side 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 also includes a capillary tube 10 and an outlet side pipe 11 thereof.
Are communicated with the low pressure side of the compressor 1. Expansion valve 8
The outlet side is connected to an inlet side pipe 13 of an evaporator 12 provided in a cold air passage such as a showcase (not shown), and the outlet side pipe 14 of the evaporator 12 is connected to an accumulator 15. Further, the accumulator 15 is connected to the suction side pipe 17 of the compressor 1 via the check valve 16.

In the above structure, a predetermined amount of R-22 refrigerant is enclosed 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 and is cooled there by an air cooling or water cooling system to be condensed and liquefied. The liquid refrigerant condensed in the condenser 3 flows into the receiver tank 5 through the outlet side pipe 4 and is stored therein at a predetermined liquid level.

The outlet side pipe 21 of the receiver tank 5
Is configured to open below the refrigerant liquid 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 advances straight in the direction of the outlet 20B due to the inertial force, but part of the liquid refrigerant is bent in the direction of the outlet 20C due to friction with the inner wall of the pipe. As a result, the liquid refrigerant flowing into the branch pipe 20 is split in the directions of the outlet 20B and the outlet 20C at a predetermined ratio.

The liquid refrigerant discharged from the outlet 20B flows into the inlet side pipe 7 of the liquid injection circuit 6, is decompressed by the capillary tube 10, and then is sucked from the outlet side pipe 11 to the low pressure side of the compressor 1 there. Evaporating and compressor 1
To cool. This prevents the occurrence of damage due to the temperature rise of the compressor 1 when the R-22 refrigerant is used. On the other hand, the liquid refrigerant discharged from the outlet 20C flows into the pipe 9 and is decompressed by the expansion valve 8, and then the evaporator 12 from the inlet side pipe 13.
It flows into and evaporates. This cools the inside of a store such as a showcase (not shown). The low-temperature refrigerant leaving the evaporator 12 returns to the compressor 1 through the suction side pipe 17 through the accumulator 15 and the check valve 16.

Next, in the refrigerating apparatus R, the refrigerant in the circuit becomes insufficient due to leakage of the refrigerant, and the condenser 3
When an abnormal state such as a decrease in the condensation capacity of the condenser 3 due to clogging with dust or the like occurs, a flash gas is generated in the refrigerant exiting the condenser 3 and the refrigerant liquid level in the receiver tank 5 decreases. When the liquid level of the receiver tank 5 eventually drops below the height at which the outlet side pipe 21 opens, the refrigerant in which the liquid and the gas are mixed flows into the outlet side pipe 21.

Here, the liquid refrigerant in the gas-liquid mixed refrigerant flowing into the branch pipe 20 has a larger density and a larger mass than the gas refrigerant. Therefore, the inertial force becomes large and a large amount of force is required to change the movement direction thereof as compared with the gas refrigerant. Therefore, the liquid refrigerant that has flowed into the branch pipe 20 is likely to go straight, and flows straight from the inlet 20A so that almost all of the liquid refrigerant flows straight to the outlet 20 for the liquid injection circuit.
It flows out from B, a part is bent by friction with the inner wall of the pipe, and comes out from the outlet 20C for the evaporator.

On the other hand, the gas refrigerant flowing into the branch pipe 20 has a small mass and a small inertial force. Further, since it has low viscosity, it is easily bent and goes toward the outlet 20C. As a result, looking at the state of the refrigerant that has been split in the branch pipe 20, the one heading for the outlet 20B is in a state where there is much liquid and less gas, and the one heading for the outlet 20C is in a state where there is less liquid and more 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 secured. It should be noted that although a refrigerant containing a large amount of gas is supplied to the pipe 9, it is also in an abnormal state and is somewhat supercooled before reaching the expansion valve 8 as described above, so a certain cooling capacity can be expected. .. In particular, since the flow is divided in the horizontal direction, it is less likely to be affected by gravity, so that in the normal state, the liquid refrigerant flows too much into the liquid injection circuit 6 and the disadvantage 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 of FIG. 3 to FIG. 5 can be considered for the branching of the refrigerant in the branch pipe 20. In each figure, the parts designated by the same reference numerals as those in FIGS. 1 and 2 have the same functions.
The branch pipe 20 shown in FIG. 3 is bent downward from an inlet 20A connected to the outlet side pipe 21, and further proceeds downward to form an outlet 20B for a liquid injection circuit at an end bent in the horizontal direction. An outlet 20C for the evaporator is formed at an end portion that is horizontally branched from a vertically descending portion.

In the case of the branch pipe 20 of FIG. 3, the refrigerant flowing into the inlet 20A is bent downward in the flowing direction along the shape of the pipe, and the refrigerant straightly proceeds to the outlet 20B,
What is bent on the way goes to the exit 20C. Therefore, when the gas-liquid mixed refrigerant flows in from the inlet 20A, the liquid refrigerant has a large mass as described above, and thus it is easy to move downward due to inertial force and gravity, and the gas refrigerant has a small mass and is easily bent halfway. Like Therefore, similarly, the refrigerant discharged from the outlet 20B is a refrigerant with a large amount of liquid and a small amount of gas, and the refrigerant discharged from the outlet 20C is a refrigerant with a large amount of gas and a small amount of liquid, and the supply of the liquid refrigerant to the liquid injection circuit 6 may be prioritized. become able to.

Further, the branch pipe 20 of FIG. 4 has an inlet 20A connected to the outlet side pipe 21 and a vertical branch, and an outlet 20C for an evaporator is provided at the end of the pipe branched upward.
However, an outlet 20B for the 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 is gravity to the lower outlet 20B and the one having a small mass is the upper outlet 20C. Will be headed for. 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 thus moves upward. Therefore, similarly, the refrigerant discharged from the outlet 20B is a refrigerant with a large amount of liquid and a small amount of gas, and the refrigerant discharged from the outlet 20C is a refrigerant with a large amount of gas and a small amount of liquid, and the supply of the liquid refrigerant to the liquid injection circuit 6 may be prioritized. become able to.

Further, the branch pipe 20 of FIG. 5 has a straight injection end 20A connected to the outlet side pipe 21 and an outlet 20 for a liquid injection circuit at an end thereof which goes straight.
B is formed, and an outlet 20C for the evaporator is formed at the end of the pipe branched upward from the middle.

In the case of the branch pipe 20 shown in FIG. 5, of the refrigerant flowing into the inlet 20A, the refrigerant that goes straight on goes to the outlet 20B, and the refrigerant that is bent upward 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, and thus it is easy for the liquid refrigerant to move forward due to the inertial force. It becomes easy to bend. Therefore, similarly, the refrigerant discharged from the outlet 20B is a refrigerant containing a large amount of liquid and a small amount of gas.
The refrigerant discharged from the refrigerant becomes a refrigerant that has a large amount of gas and a small amount of liquid, and 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 exiting the condenser is divided into the one directed to the liquid injection circuit and the one directed to the evaporator at the branch portion, but the outlet to the liquid injection circuit is used. Since the refrigerant is provided in the flow direction of the refrigerant flowing into the branch portion, the liquid refrigerant can easily flow into the liquid injection circuit as it is due to the inertial force even in an abnormal state in which the flash gas is generated in the refrigerant exiting the condenser. Therefore, since the liquid refrigerant is preferentially supplied to the liquid injection circuit, the cooling of the compressor is ensured and the durability of the compressor is improved.

According to the second aspect of the invention, the refrigerant that has exited the condenser is split into the liquid injection circuit and the evaporator in the branch portion, but the outlet to the liquid injection circuit is used. Since it is provided below the outlet toward the evaporator, the liquid refrigerant easily flows into the liquid injection circuit from the lower outlet due to gravity even in an abnormal state where flash gas is generated in the refrigerant that exits the condenser. Become. Therefore, since the liquid refrigerant is preferentially supplied to the liquid injection circuit, the cooling of the compressor is ensured and the durability of the compressor is improved.

[Brief description of 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 for 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 branch pipe having another shape.

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

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

[Explanation of symbols]

 1 Compressor 3 Condenser 6 Liquid Injection Circuit 12 Evaporator 20 Branch Pipe 20B Liquid Injection Circuit Outlet 20C Evaporator Outlet

Claims (2)

[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. In a refrigeration apparatus equipped with a liquid injection circuit that reduces the pressure of the refrigerant that is discharged from the condenser and supplies it to the low pressure side inside the compressor, the refrigerant that has discharged from the condenser is shunted and supplied to the evaporator and the liquid injection circuit. A refrigerating apparatus, which comprises a branch portion which is provided with an outlet to the liquid injection circuit in the branch portion in a direction in which a refrigerant flowing into the branch portion flows. 2. 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. In a refrigeration apparatus equipped with a liquid injection circuit that reduces the pressure of the refrigerant that is discharged from the condenser and supplies it to the low pressure side inside the compressor, the refrigerant that has discharged from the condenser is shunted and supplied to the evaporator and the liquid injection circuit. A refrigerating apparatus comprising: a branch portion which is provided with an outlet to the liquid injection circuit in the branch portion, the outlet being provided below the outlet toward the evaporator.