JPH087314Y2 - refrigerator - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a refrigerator having a compressor or a bypass circuit portion for bypassing a part of a liquid refrigerant to an upstream side of the compressor.

[0002]

2. Description of the Related Art Generally, a refrigerator constitutes a refrigeration cycle by a compressor, a heat exchanger (evaporator), a condenser, an expansion valve and the like.

By the way, the refrigerant circulating in the refrigeration cycle is changed from liquid to gas by the heat exchange action when passing through the heat exchanger, and the pressure on the downstream side of the heat exchanger is greatly reduced. As a result, the compression ratio of the compressor increases and the heat generation of the compressor also increases. Such heat generation causes overheating of the compressor when the cooling capacity is insufficient or particularly when cooling is performed at a low temperature, resulting in failure of the compressor or the like.

For this reason, conventionally, a bypass circuit portion which can bypass a part of the liquid refrigerant or the upstream side of the compressor is provided, and when the oil temperature at the bottom of the compressor exceeds a set temperature, the bypass circuit portion is provided. Was opened to cool the compressor by so-called liquid injection in which a part of the liquid refrigerant is supplied into the compressor. According to this method, the liquid refrigerant evaporates inside the compressor, and the heat of the compressor is taken during the evaporation, so that the compressor is cooled. The liquid injection is continuously performed until the temperature of the compressor becomes lower than the set temperature.

[0005]

However, since the cooling capacity is reduced by about 7 to 8% by performing liquid injection in the conventional refrigerator, when installing the refrigerator,
There is a problem that a refrigerator with a large capacity, that is, a model with a large cooling capacity needs to be installed in advance, which makes the refrigerator larger and more expensive.

Liquid injection is continued until the oil temperature at the bottom of the compressor falls below a set temperature. Normally, however, this type of refrigerator sensitively affects the temperature change state of the compressor depending on the operating conditions. Therefore, by only detecting the oil temperature at the bottom of the compressor, it is not possible to obtain an accurate timing for executing liquid injection,
After all, there were problems such as unnecessary energy loss.

The present invention solves the problems existing in the prior art as described above, and an object thereof is to provide a refrigerator which can contribute to miniaturization and cost reduction of the refrigerator and further reduction of energy loss. It is a thing.

[0008]

[MEANS FOR SOLVING THE PROBLEMS] The present invention is a refrigeration cycle C.
The cooling is performed by increasing the opening of the evaporation pressure adjusting valve 9 at
Cooling mode and heating mode for heating with a small opening
By performing constant temperature control by repeating the above , the bypass circuit unit 3 that can bypass a part of the liquid refrigerant in the refrigeration cycle C to the compressor 2 or the upstream side of the compressor 2, and the opening / closing unit 4 that opens and closes the bypass circuit unit 3 When configuring the refrigerator 1 that includes the temperature detection unit 5 that detects the oil temperature of the compressor 2 and the control unit 6 that controls the opening / closing unit 4 based on the detected temperature Td, especially when the refrigeration cycle C is in the heating mode. Whether or not it is the opening of the evaporation pressure control valve (hereinafter referred to as EPR) 9
A mode detection unit 7 for detecting the temperature based on a control voltage Ec for controlling the temperature is provided, the mode detection unit 7 detects the heating mode, and the opening / closing unit 4 is opened only when the detected temperature Td of the temperature detection unit 5 is equal to or higher than the set temperature. It is special that the control unit 6 for controlling the side is provided.
To collect.

[0009]

According to the refrigerator 1 according to the present invention, the temperature detecting unit 5
Detects the oil temperature of the compressor 2 and the mode detector 7 detects whether the refrigeration cycle C is in the heating mode.

In this case, the heating mode can be detected as follows. That is, the refrigerator 1 puts the compressor 2 in a continuous operation state,
By controlling the EPR 9 and the like provided in the refrigeration cycle C, the heating mode and the cooling mode are repeated to perform constant temperature control. Therefore, the opening degree of the EPR 9 becomes small in the heating mode, while the opening degree of the EPR 9 becomes large in the cooling mode. Therefore, by monitoring the magnitude of the control voltage Ec that determines the opening degree of the EPR 9, it is possible to detect whether the mode is the heating mode or the cooling mode.

Then, the temperature Td detected by the temperature detector 5
Is equal to or higher than the set temperature, and at the same time, when the mode detection unit 7 detects the heating mode, liquid injection is performed. That is, in this case, the opening / closing part 4 is controlled to the open side by the control part 6, and a part of the liquid refrigerant is supplied to the compressor 2 or the upstream side of the compressor 2 through the bypass circuit part 3.

Therefore, even when the temperature Td detected by the temperature detector 5 is equal to or higher than the set temperature, the mode detector 7
Therefore, when the heating mode is not detected, that is, in the cooling mode, the opening / closing part 4 is controlled to the closed side, and the liquid injection is not performed.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments according to the present invention will be described below in detail with reference to the drawings.

First, the configuration of the refrigerator 1 according to the present invention will be described with reference to FIG.

The refrigerator 1 constitutes a refrigeration cycle C in which a refrigerant circulates through a path of a compressor 2, a condenser 11, an expansion valve 12, an evaporator (heat exchanger) 13 and an EPR 9. Also, the compressor 2
A constant pressure expansion valve (hereinafter referred to as CCV) 14 is connected in parallel between the upstream side and the downstream side of the compressor to configure a compressor bypass section, and between the downstream side of the condenser 11 and the inside of the compressor 2. By-pass circuit section 3 for liquid injection in which a solenoid valve 4x (opening / closing section 4) and a capillary tube 15 are connected in series
Connect. The expansion valve 12 is controlled by the detection result of the temperature sensing unit 16 attached downstream of the evaporator 13.

On the other hand, 6 is a control unit, and a temperature sensor 5x (temperature detection unit 5) for detecting the temperature of the oil contained in the bottom of the compressor 2 is connected to the input side of the control unit 6 and A control voltage Ec for controlling the EPR 9 is input. The output side of the control unit 6 is connected to the solenoid valve 4x.

Next, the operation of the refrigerator 1 and the function of the control unit 6 will be described with reference to FIGS. 1 and 2.

First, the refrigerator 1 performs a cooling operation based on the refrigeration cycle C, and the object to be cooled is cooled by the evaporator 13 which is a heat exchanger. At this time, the compressor 2 is constantly operating, and when the temperature of the object to be cooled is higher than the set temperature, the EPR 9 opens and the CCV 14 closes. Then, when the temperature of the object to be cooled approaches the set temperature, the opening degree of the EPR 9 is adjusted. On the other hand, when the temperature of the object to be cooled falls below the set temperature, the EPR 9 is closed and the CCV 14 is opened to enter the heating mode. When the temperature of the object to be cooled rises and becomes close to the set temperature, the EPR 9 starts to open and CC
V14 is closed to enter the cooling mode. In this way, the temperature of the object to be cooled is maintained at the set temperature.

The opening of the EPR 9 is set in proportion to the input control voltage Ec. When the control voltage Ec is high, the opening becomes small, the heating mode is set, and when the control voltage Ec is low, the opening is set. Becomes larger and the cooling mode is set.

Next, assume that the oil temperature at the bottom of the compressor 2 rises. In this case, the detected temperature Td (temperature detection signal) obtained from the temperature sensor 5x is input to the controller 6 and compared with the preset temperature Ts set in the controller 6. Then, it is determined whether the detected temperature Td is equal to or higher than the set temperature Ts (step 51).

At the same time, in the control unit 6, the EP
It is determined whether the control voltage Ec applied to R9 is equal to or higher than a preset setting voltage Es, that is, whether it is in the heating mode (step 52).

When the detected temperature Td is equal to or higher than the set temperature Ts and the heating mode is set (Ec ≧ Es), the solenoid valve 4x is opened to bypass the liquid refrigerant and liquid injection is performed. That is, the compressor 2 is cooled (step 53). On the other hand, the detected temperature Td is the set temperature Ts
If either or both of less than or the cooling mode is used, the solenoid valve 4x is closed and liquid injection is not performed (step 54).

The embodiment has been described in detail above.
The present invention is not limited to such an embodiment.
For example, the heating mode is detected by monitoring the control voltage of the EPR, but in addition, a pressure change (downstream pressure of the EPR) due to opening and closing of the CCV may be detected, or the temperature of the object to be cooled is detected. The detection result of the temperature sensor may be used. Further, although the liquid refrigerant in the liquid injection is illustrated as being supplied to the inside of the compressor, it may be supplied to the upstream side of the compressor. In addition, the detailed configuration and the like can be arbitrarily changed without departing from the gist of the present invention.

[0024]

As described above, the refrigerator according to the present invention determines whether the refrigeration cycle is in the heating mode or not depending on the opening degree of the evaporation pressure adjusting valve.
A control unit that provides a mode detection unit that detects the temperature based on a control voltage that controls the temperature control unit, detects the heating mode, and controls the opening / closing unit to the open side only when the temperature detected by the temperature detection unit is equal to or higher than the set temperature. Since the above is provided, the following remarkable effects are achieved. When installing the refrigerator, it is not necessary to consider the capacity margin associated with the liquid injection, which can contribute to downsizing and cost reduction of the refrigerator. Since it is possible to obtain an accurate control timing when performing liquid injection, unnecessary energy loss can be eliminated.

[Brief description of drawings]

FIG. 1 is a block diagram of a refrigerator according to the present invention,

FIG. 2 is a flowchart showing a function of a control unit in the refrigerator.

[Explanation of symbols]

, 1: refrigerator, 2: compressor, 3: bypass circuit part, 4:
Open / close unit, 5: temperature detection unit, 6: control unit, 7: mode detection unit, 9: EPR, C: refrigeration cycle, Ec: control voltage

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiyuki Miyashita No. 246 Kodaka, Suzaka City, Nagano Prefecture Orion Machinery Co., Ltd. (56) Reference JP-A-64-33471 (JP, A) JP-A-1-263461 (JP, A)

Claims (1)

[Scope of utility model registration request] 1. An evaporation pressure control valve in a refrigeration cycle.
Cooling mode in which the opening is increased and cooling is performed, and the opening is decreased
Temperature control by repeating the heating mode
The bypass circuit part that can bypass the compressor or part of the liquid refrigerant in the refrigeration cycle to the compressor or the upstream side of the compressor, the opening and closing part that opens and closes the bypass circuit part, and the temperature that detects the oil temperature of the compressor. a detection unit, in the refrigerating machine comprising a control unit for controlling the opening and closing unit based on the detected temperature, whether the refrigeration cycle is heating mode, the evaporation pressure
A mode detector that detects based on the control voltage that controls the opening of the force adjustment valve is provided.The mode detector detects the heating mode and opens the switch only when the temperature detected by the temperature detector is higher than the set temperature. A refrigerator provided with a control unit for controlling the side.