JPH09318205A - Refrigerating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain the increase of a high-pressure pressure in the defrosting operation by providing a bypass circuit for bypassing hot gas to the suction pipe side of a compressor and interposing a bypass valve which opens when the high-pressure pressure becomes higher than a set pressure at the time of defrosting operation in the bypass circuit. SOLUTION: A refrigerating device is provided with a refrigerant circuit, constituted of a compressor 1, a condenser 3, a choking mechanism 5 and an evaporator 6, which are connected sequentially, while a bypass circuit 19, connecting the discharging pipe 18 of the compressor 1 to the suction pipe 8 of the same, is provided and a bypass valve 20 is interposed in the bypass circuit 19. In this case, the bypass valve 20 is controlled upon defrosting operation so as to be opened by a command from a controller 22 when a high- pressure pressure, detected by a high-pressure sensor 21 installed in a high- pressure refrigerant circuit, has become higher than a set pressure. According to this method, the increase of the high-pressure pressure in the defrosting operation can be restrained.

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 refrigerator such as a refrigerator and a refrigerated showcase.

[0002]

2. Description of the Related Art A refrigerant circuit of this type of refrigerating apparatus is shown in FIG. During the cooling operation, the gas refrigerant discharged from the compressor 1 enters the condenser 3 through the discharge pipe 18 and the three-way valve 15 and radiates heat to the outside to be condensed and liquefied. This liquid refrigerant enters the throttling mechanism 5 including an expansion valve and the like via the receiver 4, and is throttled here to adiabatically expand into a gas-liquid two-phase.

This refrigerant enters the evaporator 6, where it is evaporated and vaporized by cooling the air in the refrigerator, and then returns to the compressor 1 through the accumulator 7 and the suction pipe 8.

The three-way valve 15 is switched during the defrost operation. Then, the hot gas discharged from the compressor 1 passes through the three-way valve 15 and the defrost hot gas bypass circuit 16
Enters the evaporator 6 through the check valve 17 and the throttling mechanism 5,
Here, after the frost attached to the surface is melted to lower the temperature, the compressor 1 is passed through the accumulator 7 and the suction pipe 8.
Return to

[0005]

In the above conventional refrigeration system, there is a risk that the high pressure rises immediately before the end of the defrosting operation and the high pressure protection device operates, causing the refrigeration system to abnormally stop.

[0006]

The present invention has been invented to solve the above problems, and its gist is to connect a compressor, a condenser, a throttle mechanism, and an evaporator in this order. A refrigerating apparatus comprising a refrigerant circuit formed by the above, and a hot gas bypass circuit for defrosting provided between the discharge pipe of the compressor and the inlet of the evaporator. A bypass circuit for bypassing hot gas to the suction pipe side of the compressor is provided in the bypass circuit, and a bypass valve that opens when the high-pressure pressure becomes equal to or higher than a set pressure during defrost operation is provided in the bypass circuit. Located in the freezer.

However, during the defrosting operation, when the high pressure exceeds the set pressure, the bypass valve opens, and accordingly hot gas passes through the bypass circuit and bypasses to the suction pipe side of the compressor.

The gist of the second invention is that it comprises a refrigerant circuit in which a compressor, a condenser, a throttle mechanism and an evaporator are connected in this order, and a discharge pipe of the compressor and an inlet of the evaporator. In the refrigerating apparatus having a hot gas bypass circuit for defrosting between the oil and oil, an oil separator is provided in the discharge pipe of the compressor, and the oil separated by the oil separator is returned to the suction pipe of the compressor. A return circuit is provided, and a bypass circuit that bypasses hot gas to the suction pipe side of the compressor is connected to this oil return circuit, and this bypass circuit opens when the high pressure exceeds a set pressure during defrost operation. A refrigeration system characterized by having a valve interposed.

However, during the defrost operation, when the high pressure exceeds the set pressure, the bypass valve opens, and accordingly hot gas bypasses to the suction pipe side of the compressor through the oil return circuit and the bypass circuit. .

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The first embodiment of the present invention is shown in FIGS. 1 and 2, FIG. 1 is a system diagram, and FIG. 2 is a control flow chart. In this first embodiment, the compressor 1
A bypass circuit 19 that connects the discharge pipe 18 and the suction pipe 8 is provided, and a bypass valve 20 is interposed in the bypass circuit 19.

The bypass valve 20 is adapted to be opened by a command from the controller 22 when the high pressure detected by the high pressure sensor 21 installed in the high pressure refrigerant circuit during the defrost operation exceeds a set pressure. Other configurations are the same as those of the conventional one shown in FIG. 4, and corresponding members are designated by the same reference numerals and the description thereof is omitted.

However, during the cooling operation of the refrigeration system, the bypass valve 20 is closed, so that the refrigerant is the compressor 1 and the three-way valve.
15, condenser 3, receiver 4, throttle mechanism 5, evaporator 6, and accumulator 7 are circulated in this order.

During the defrost operation, the three-way valve 15 is switched, so that the refrigerant is the compressor 1, the three-way valve 15, the defrost hot gas bypass circuit 16, the check valve 17, the throttle mechanism 5,
The evaporator 6 and the accumulator 7 are circulated in this order.

During this defrosting operation, as shown in FIG. 2, when the high pressure rises above the set pressure, the bypass valve
Since 20 is opened, the hot gas discharged from the compressor 1 is discharged by the discharge pipe 18, the bypass circuit 19, the bypass valve 20, and the suction pipe 8.
After returning to the compressor 1, the high pressure is reduced.

When the high pressure falls below the set pressure, the bypass valve 20 is closed again and the defrost operation is continued. When the defrosting ends, that is, when the frost adhering to the evaporator 6 is removed, the defrosting operation ends.

Thus, since the high pressure can be prevented from rising during the defrost operation, it is possible to prevent the abnormal stop of the refrigeration system due to the operation of the high pressure protection device.

A second embodiment of the invention is shown in FIG. In the second embodiment, the oil separator 2 is arranged in the discharge pipe 18, and the oil return circuit 9 for returning the oil separated by the oil separator 2 to the suction pipe 8 of the compressor 1 is provided. There is.

An oil cooler 10, an oil return solenoid valve 11 and a capillary tube 12 are provided in the oil return circuit 9. A bypass circuit 13 is connected to the oil return circuit 9 in parallel with the oil return electromagnetic valve 11 and the capillary tube 12, and a bypass valve 14 is interposed in the bypass circuit 13.

The bypass valve 14 has a high pressure sensor 21.
When the high pressure detected by exceeds the set pressure, it is opened by a command from the controller 22. Other configurations are the same as those of the conventional one shown in FIG. 4, and corresponding members are designated by the same reference numerals and the description thereof is omitted.

Thus, during the cooling operation of the refrigeration system, the refrigerant gas discharged from the compressor 1 enters the oil separator 2, where the oil contained in the refrigerant gas is separated and temporarily stored at the bottom thereof. It

When the oil return solenoid valve 11 is opened, the oil stored in the oil separator 2 passes through the oil return circuit 9 and enters the oil cooler 10 where it is cooled, and then the oil return solenoid valve 11 is cooled. After that, the pressure is reduced by the capillary tube 12 into the suction pipe 8, and the gas returns to the compressor 1 along with the refrigerant gas flowing through the suction pipe 8.

During defrost operation, when the high pressure rises above the set pressure, the bypass valve 14 opens, so that the hot gas that has entered the oil separator 2 causes the oil return circuit 9, oil cooler 10, bypass circuit 13, bypass valve 14, Oil return circuit 9
Through this order and enter the suction pipe 8.

In this way, the rise of the high pressure during the defrost operation is suppressed, and the abnormal stop of the refrigeration system due to the operation of the high pressure protection device can be prevented.

[0024]

According to the first aspect of the present invention,
During the defrost operation, when the high pressure becomes equal to or higher than the set pressure, the bypass valve is opened, and the hot gas bypasses the intake pipe of the compressor through the bypass circuit. It is possible to prevent an abnormal stop of the refrigeration system due to the operation of the high-voltage protection device.

According to the second aspect of the present invention, when the high pressure becomes equal to or higher than the set pressure during the defrosting operation, the bypass valve opens, and hot gas passes through the oil return circuit and the bypass circuit and the suction pipe of the compressor. By bypassing to the side, the same effect as the first aspect of the invention is obtained.

[Brief description of drawings]

FIG. 1 is a system diagram showing a first embodiment of the present invention.

FIG. 2 is a control flowchart of the first embodiment.

FIG. 3 is a system diagram showing a second embodiment of the present invention.

FIG. 4 is a refrigerant circuit diagram of a conventional refrigeration system.

[Explanation of symbols]

 1 Compressor 18 Discharge pipe 8 Suction pipe 3 Condenser 4 Receiver 5 Throttling mechanism 6 Evaporator 7 Accumulator 15 Three-way valve 16 Hot gas bypass circuit 17 Check valve 19 Bypass circuit 20 Bypass valve

Claims (2)

[Claims] A defrosting hot gas bypass is provided between a discharge pipe of the compressor and an inlet of the evaporator, comprising a refrigerant circuit in which a compressor, a condenser, a throttle mechanism, and an evaporator are connected in this order. In a refrigerating device having a circuit, a bypass circuit for bypassing hot gas to the suction pipe side of the compressor is provided between the discharge pipe and the suction pipe of the compressor, and a high pressure during defrost operation is provided in this bypass circuit. A refrigeration system having a bypass valve that opens when the pressure exceeds a set pressure. 2. A defrosting hot gas bypass is provided between a discharge pipe of the compressor and an inlet of the evaporator, comprising a refrigerant circuit in which a compressor, a condenser, a throttle mechanism and an evaporator are connected in this order. In a refrigerating apparatus having a circuit, an oil separator is provided in a discharge pipe of the compressor, and an oil return circuit for returning the oil separated by the oil separator to an intake pipe of the compressor is provided. A bypass circuit for bypassing hot gas to the suction pipe side of the compressor is connected to the bypass circuit, and a bypass valve that opens when the high-pressure pressure exceeds a set pressure during defrost operation is inserted in the bypass circuit. Refrigerating device.