JPH109727A - Freezer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectually melt and remove frost adhering to an evaporator by providing a bypass circuit for allowing a refrigerant to flow only upon defrosting operation parallelly to a pressure reducing mechanism, and further providing a constant pressure expansion valve as a defrosting pressure reducing mechanism. SOLUTION: Upon defrosting operation, a refrigerant enters an evaporator 9 after passage through a compressor 1, and a four-way valve 2 as indicated by a broken arrow to melt frost adhering to the surface thereof and hence to lower the temperature. The refrigerant returns to the compressor 1 after passage through a bypass circuit 12 and a check valve 14, a constant pressure expansion valve 20, a condenser 3, a four-way valve 2, an accumulator 10 interposed in the bypass circuit. Thus, upon the defrosting operation, the refrigerant flows through the constant pressure expansion valve 20 to hereby become constant pressure and enters the condenser 3 where it is evaporated to hereby make evaporation pressure constant. Thus, even at low fresh air temperature heat is sufficiently absorbed from the fresh air in the condenser 3 so that frost adhering to the evaporator 9 is effectually melted and removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner,
The present invention relates to a refrigerating device such as a refrigerator.

[0002]

2. Description of the Related Art FIG.
Is shown in During the cooling operation of the refrigeration apparatus, the compressor 1
As shown by a solid line arrow, the refrigerant discharged from the condenser enters the condenser 3 via the four-way valve 2 and radiates heat to the outside air blown by the condenser fan 4 to be condensed and liquefied.

[0003] This liquid refrigerant is adiabatically expanded by being throttled by a throttle mechanism 8 composed of a capillary tube, and then evaporated and vaporized by cooling the internal air blown by an evaporator fan 11 by an evaporator 9. , Four-way valve 2
And returns to the compressor 1 via the accumulator 10.

When frost forms on the evaporator 9, the four-way valve 2 is switched in the reverse manner to the above, and the defrost operation is performed by the reverse cycle. During this defrost operation, the refrigerant enters the evaporator 9 through the compressor 1 and the four-way valve 2 as shown by the broken line arrow, where the temperature is lowered by melting the frost adhering to its surface. , The condenser 3, the four-way valve 2, and the accumulator 10 are returned to the compressor 1.

[0005]

In the above-mentioned conventional refrigeration system, during the defrost operation, the refrigerant flows into the condenser 3 via the capillary tube 8 and evaporates there, so that the evaporation pressure can be controlled to be constant. Can not. Therefore, when the outside air temperature falls to, for example, -15 ° C. or less, the amount of heat absorbed in the condenser 3 decreases, and there is a problem that frost attached to the evaporator 9 cannot be efficiently removed.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and its gist is to provide a compressor, a four-way valve, a condenser, a pressure reducing mechanism, an evaporator, and the like. A refrigeration system comprising a refrigerant circuit comprising: a defrost operation by switching the four-way valve and performing a reverse cycle by a reverse cycle; a bypass circuit for flowing a refrigerant only during the defrost operation in parallel with the pressure reduction mechanism; Provided in the refrigeration apparatus.

[0007] The bypass circuit may be formed by a circuit having a check valve connected in parallel with the pressure reducing mechanism.

[0008] A circuit having a check valve for flowing a refrigerant only during the cooling operation can be connected in parallel with the constant pressure expansion valve.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention is shown in FIG. A bypass circuit 12 for flowing the refrigerant only during the defrost operation is connected in parallel with the pressure reducing mechanism 8.
A check valve 14 is interposed in 12.

A constant pressure expansion valve 20 is provided as a defrost pressure reducing mechanism, and a circuit 17 having a check valve 27 for flowing a refrigerant only during the cooling operation is connected to the constant pressure expansion valve 20 in parallel. The other configuration is the same as that of the conventional one shown in FIG. 2, and the corresponding members are denoted by the same reference numerals and description thereof will be omitted.

During the cooling operation, the refrigerant discharged from the compressor 1 enters the condenser 3 through the four-way valve 2 as shown by a solid arrow, and the refrigerant is discharged to the outside air blown by the condenser fan 4. Condensed and liquefied by releasing heat. This liquid refrigerant enters the pressure reducing mechanism 8 via the circuit 17 and the check valve 27 interposed therein, and is adiabatically expanded by being throttled here.

This refrigerant enters the evaporator 9, where it is evaporated and vaporized by cooling the inside air blown by the evaporator fan 11, and then returns to the compressor 1 via the four-way valve 2 and the accumulator 10.

During the defrost operation, the refrigerant enters the evaporator 9 via the compressor 1 and the four-way valve 2 as shown by the dashed arrow,
Here, the temperature is lowered by melting the frost attached to the surface. This refrigerant returns to the compressor 1 through the bypass circuit 12, the check valve 14, the constant pressure expansion valve 20, the condenser 3, the four-way valve 2, and the accumulator 10 interposed in the bypass circuit 12.

Thus, during the defrost operation, the refrigerant flows through the constant-pressure expansion valve 20 to have a constant pressure and flows into the condenser 3, where it evaporates, so that the evaporation pressure becomes constant. Therefore, even at a low outside air temperature, the condenser 3 can sufficiently absorb heat from the outside air, so that the frost attached to the evaporator 9 can be efficiently melted and removed.

[0015]

According to the present invention, during defrost operation,
The refrigerant bypasses the pressure reducing mechanism, reaches a constant pressure through the constant pressure expansion valve, and evaporates in the condenser. Therefore, since the evaporation pressure can be kept constant, heat can be sufficiently absorbed by the condenser even at a low outside air temperature, and as a result, the frost attached to the evaporator can be efficiently melted and removed.

If the bypass circuit is formed by a circuit having a check valve connected in parallel with the pressure reducing mechanism, the refrigerant can flow through the pressure reducing mechanism during the cooling operation, and can flow through the bypass circuit during the defrost operation. .

If a circuit having a check valve for flowing the refrigerant only during the cooling operation is connected in parallel with the constant pressure expansion valve, the refrigerant can flow through the constant pressure expansion valve only during the defrost operation.

[Brief description of the drawings]

FIG. 1 is a refrigerant circuit diagram showing an embodiment of the present invention.

FIG. 2 is a refrigerant circuit diagram of a conventional refrigeration apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 2 Four-way valve 3 Condenser 8 Pressure reducing mechanism 12 Bypass circuit 14 Check valve 20 Constant pressure expansion valve 17 Circuit 27 Check valve

Claims (3)

[Claims] 1. A refrigerating apparatus comprising a refrigerant circuit including a compressor, a four-way valve, a condenser, a pressure reducing mechanism, an evaporator, and the like, and performing a defrost operation by a reverse cycle by switching the four-way valve. A refrigerating apparatus comprising: a bypass circuit for flowing a refrigerant only during a defrost operation; and a constant pressure expansion valve as a defrost pressure reducing mechanism. 2. The refrigeration system according to claim 1, wherein said bypass circuit is formed by a circuit having a check valve connected in parallel with said pressure reducing mechanism. 3. The refrigeration system according to claim 1, wherein a circuit having a check valve for flowing a refrigerant only during a cooling operation is connected in parallel with said constant pressure expansion valve.