JP2002130846A - Refrigerating plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigerating plant that can secure the reliability of a compressor when the compressor is operated at a high compression ratio. SOLUTION: This refrigerating plant is provided with detectors 6 and 7 which detect the discharge pressure and suction pressure of the compressor 1, the condensing temperature of a condenser 2, or the evaporative temperature of an evaporator 5 and a controller 8 which stops the compressor 1 when the discharge pressure or condensing temperature detected by means of the detectors 6 and 7 exceeds a boundary condition for securing reliability decided based on the suction pressure or evaporative temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration apparatus, and more particularly to a refrigeration apparatus provided with a blower for a condenser.

[0002]

2. Description of the Related Art FIG. 5 is a system diagram showing a configuration of a conventional refrigeration apparatus disclosed in, for example, Japanese Utility Model Laid-Open No. 7-6651. In this figure, 1 is a compressor, 2 is a condenser, and the refrigerant discharged from the compressor is condensed by exchanging heat with air by blowing air from a condenser blower 3. 4 is a throttle device for reducing the pressure of the liquid refrigerant condensed by the condenser 2,
5 is an evaporator for evaporating the depressurized refrigerant and sucking the gas refrigerant into the compressor 1, 6 is provided on the discharge side of the compressor 1,
A discharge pressure sensor 7 for detecting a discharge pressure; a suction pressure sensor 7 provided on the suction side of the compressor 1 for detecting a suction pressure;
Reference numeral 8 denotes a control device that controls the rotation speed of the condenser blower 3 based on the detection results of the discharge pressure sensor 6 and the suction pressure sensor 7.

Next, the operation of the conventional device will be described.
The gas refrigerant that has been compressed by the compressor 1 and has become high temperature and high pressure is
In the condenser 2, heat is exchanged with air by blowing air from the condenser blower 3 to become a high-pressure liquid refrigerant. This liquid refrigerant is supplied to the expansion device 4
The pressure is reduced in the evaporator 5, and the air is exchanged with air by the air blown from an evaporator blower (not shown) in the evaporator 5 to become a low-pressure gas refrigerant, which is sucked into the compressor 1. When the temperature of the air (ambient temperature) at which heat is exchanged in the condenser 2 is, for example, 32 ° C., the relationship between the discharge pressure and the suction pressure of the compressor 1 is as shown by the line A in FIG. When the outside air temperature rises to 40 ° C., the discharge pressure of the compressor 1 increases in accordance with the rise in the outside air temperature, and the relationship with the suction pressure is as shown by the line B in FIG. In addition, the compressor 1
If the discharge pressure of the compressor falls below a certain relationship with respect to the suction pressure, the reliability of the compressor deteriorates.
The discharge pressure is increased by taking measures such as reducing the cooling capacity of the condenser 2. For example, the blower 3 for the condenser is decelerated so that the discharge pressure does not fall below the line F in FIG. On the other hand, when the discharge pressure of the compressor 1 rises and exceeds the line C in FIG. 6, the compressor is generally stopped (stop of high-pressure cut protection) at the line C from the viewpoint of safety.

[0004]

The ordinary refrigerating apparatus including the conventional refrigerating apparatus having the above-described structure can continuously operate the refrigerating apparatus even at the ambient temperature at the upper limit of the use range and the suction pressure at the upper limit of the use range. It is designed to be. That is,
When the ambient temperature at the upper limit of the use range is 40 ° C., the heat exchange performance of the condenser 2 and the blower 3 for the condenser is designed so that the suction pressure at the upper limit of the use range does not exceed the C line as shown by the line B in FIG. Have been. Therefore, when the ambient temperature rises abnormally (for example, 50 ° C or more), when the heat exchange performance of the condenser deteriorates due to dirt on the condenser, etc., when the air volume of the blower for the condenser falls abnormally due to malfunction of the blower, The relationship between the discharge pressure and the suction pressure of the compressor 1 is as indicated by the line D in FIG. 6 and may exceed the line C. However, even in such a situation, the suction pressure is close to the lower limit of the working range. For example, when driving at point D1 on line D,
Because the discharge pressure does not reach the high pressure cut pressure (line C),
The operation of the refrigeration system may be continued. If the operation state of such a high compression ratio (here, compression ratio = discharge pressure / suction pressure) is continued, the following problem occurs. The efficiency of the compressor deteriorates, causing the motor winding temperature of the compressor to rise, the compressor oil temperature to rise, and the compressor discharge gas temperature to rise,
Further, the temperature of the entire refrigeration system rises, and the reliability of the equipment constituting the refrigeration system decreases. In the case of a component constituting the inside of the compressor, for example, a scroll compressor, the thrust receiver is damaged or seized. An unbalanced force according to the compression ratio acts on the thrust receiver, and the higher the compression ratio, the more the thrust behavior becomes abnormal, eventually leading to breakage and seizure.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a refrigeration apparatus which can ensure the reliability of a compressor at a high compression ratio operation.

[0006]

SUMMARY OF THE INVENTION A refrigerating apparatus according to the present invention comprises a compressor, a condenser for exchanging heat with air discharged from the compressor by heat exchange with air by a blower for the condenser, and a condenser. A refrigerating device comprising a throttle device for decompressing the liquid refrigerant condensed by the evaporator, and an evaporator for evaporating the depressurized refrigerant and sucking the gas refrigerant into the compressor. A detection device for detecting the suction pressure or the condensation temperature of the condenser or the evaporation temperature of the evaporator, and a boundary for ensuring reliability in which the discharge pressure or the condensation temperature detected by the detection device is determined based on the suction pressure or the evaporation temperature. And a control device for stopping the compressor when the condition is exceeded.

A refrigerating apparatus according to the present invention further comprises a detecting device for detecting a discharge pressure and a suction pressure of a compressor, a condensing temperature of a condenser or an evaporating temperature of an evaporator, and a discharge pressure or a pressure detected by the detecting device. When the condensing temperature exceeds a boundary condition for ensuring reliability determined based on the suction pressure or the evaporating temperature, a control device for operating the compressor blower at full speed and stopping the compressor is provided.

The refrigerating apparatus according to the present invention also includes a bypass circuit connecting the discharge side and the suction side of the compressor, an on-off valve provided in the bypass circuit and normally closed, and a compressor for the compressor. A detector for detecting the discharge pressure and the suction pressure, the condensation temperature of the condenser, or the evaporation temperature of the evaporator, and ensuring the reliability that the discharge pressure or the condensation temperature detected by the detection device is determined based on the suction pressure or the evaporation temperature. And a control device for opening the on-off valve while the compressor is running when the boundary condition is exceeded.

The refrigerating apparatus according to the present invention also includes a capacity control device for increasing and decreasing the refrigerating capacity of the compressor, and a detecting device for detecting a discharge pressure and a suction pressure of the compressor, a condensing temperature of the condenser, or an evaporating temperature of the evaporator. When the discharge pressure or the condensing temperature detected by the detecting device exceeds the boundary condition for securing reliability determined based on the suction pressure or the evaporating temperature, the capacity control device is operated to reduce the refrigerating capacity of the compressor. And a control device for reducing.

The refrigerating apparatus according to the present invention further includes a detecting device for detecting a discharge pressure and a suction pressure of a compressor, a condensing temperature of a condenser or an evaporating temperature of an evaporator, and a discharge pressure or a pressure detected by the detecting device. Before the condensation temperature reaches a boundary condition for ensuring reliability determined based on the suction pressure or the evaporation temperature, a control device for operating the condenser blower at full speed with the compressor operated.

In the refrigeration apparatus according to the present invention, when the compressor blower is operated at full speed, the discharge pressure corresponding to the suction pressure of the compressor at a predetermined ambient temperature within a range where the discharge pressure of the compressor does not reach the boundary condition. This is performed in a region where the pressure is exceeded.

In the refrigeration apparatus according to the present invention, the boundary condition is set such that the relationship between the discharge pressure and the suction pressure of the compressor becomes a straight line.

In the refrigeration apparatus according to the present invention, the boundary conditions are set such that the relationship between the discharge pressure and the suction pressure of the compressor is a quadratic curve.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a system diagram showing a configuration of the first embodiment, and FIG. 2 is a characteristic diagram showing a relationship between a discharge pressure and a suction pressure of a compressor. In FIG. 1, reference numeral 1 denotes a compressor, and reference numeral 2 denotes a condenser. The refrigerant discharged from the compressor is condensed by exchanging heat with air by blowing air from a blower 3 for the condenser. 4 is a throttling device for decompressing the liquid refrigerant condensed by the condenser 2, 5 is an evaporator for evaporating the depressurized refrigerant and sucking gas refrigerant into the compressor 1, and 6 is provided on the discharge side of the compressor 1. , A discharge pressure sensor as a detecting device for detecting the discharge pressure, 7 is provided on the suction side of the compressor 1, a suction pressure sensor as a detecting device for detecting the suction pressure, and 8 is a discharge pressure sensor 6 and a suction pressure sensor 7. Is a control device that controls the rotation speed of the condenser blower 3 and the operation and stop of the compressor 1 based on the detection result of

Next, the operation of the first embodiment will be described. The gas refrigerant which has been compressed by the compressor 1 and has become high temperature and high pressure exchanges heat with air in the condenser 2 by blowing air from the condenser blower 3 to become a high pressure liquid refrigerant. The liquid refrigerant is decompressed by the expansion device 4, heat-exchanges with air by blowing air from an evaporator blower (not shown) in the evaporator 5, becomes a low-pressure gas refrigerant, and is sucked into the compressor 1. Also, in FIG.
The line indicates the relationship between the discharge pressure and the suction pressure of the compressor 1 when the ambient temperature at which heat is exchanged in the condenser 2 is at the upper limit of the working range (for example, 40 ° C.). Indicates pressure. The line E is set as a boundary condition to be maintained in order to ensure the reliability of the refrigerating device or the compressor in a region lower than the discharge pressure at which the high-pressure cut protection is stopped. For example, (discharge pressure) = (suction pressure) ) × 4 +
It is a line of 1.4 (MPaabs).

In the case where the discharge pressure of the compressor 1 becomes equal to or higher than the E line in the range below the E1 point of the E line or becomes equal to or higher than the C line, in this embodiment, the reliability of the refrigerating apparatus and the compressor is improved. The compressor 1 is controlled by the control device 8 in order to secure
Stop operation of. In addition, normally, when the operation of the compressor 1 is stopped, the rotation of the condenser blower 3 is also stopped. However, in this case, the discharge pressure of the compressor during the protection stop is caused by the natural cooling of the condenser 2. As a gradual decrease, as a remedy, the control device 8 operates the condenser blower 3 at full speed even while the protection of the compressor 1 is stopped. As a result, the decrease in the discharge pressure of the compressor 1 is further accelerated, and the compressor 1 can be quickly restored to a restartable state. Further, in this embodiment, a boundary condition for ensuring reliability determined based on the discharge pressure and the suction pressure,
That is, although the E-line in FIG. 2 is defined as a straight line, the E-line does not necessarily have to be a straight line, and may be defined by a quadratic curve or the like. In setting the boundary conditions,
The condensation temperature may be used instead of the discharge pressure, and the evaporation temperature may be used instead of the suction pressure. However, in this case, it goes without saying that the conversion is performed for each of the discharge pressure and the condensation temperature and the suction pressure and the evaporation temperature, and the boundary conditions are set based on the conversion results.

Embodiment 2 FIG. Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 3 shows the second embodiment.
FIG. 2 is a system diagram showing the configuration of FIG. In this figure, the same or corresponding parts as those in FIG. 1 in that a bypass circuit for connecting the discharge side and the suction side of the compressor is provided, and an on-off valve is provided in the bypass circuit. That is, in FIG. 3, reference numeral 9 denotes a bypass circuit connecting the discharge side and the suction side of the compressor 1;
Is an on-off valve provided in the bypass circuit for opening and closing the bypass circuit, and is normally closed, but is opened by the control device 8 when the above-mentioned boundary condition is exceeded.

In such a configuration, when the discharge pressure of the compressor 1 becomes equal to or higher than the line E or C in FIG.
Opens the on-off valve 10 to ensure the reliability of the refrigerating device and the compressor. As a result, the amount of circulating refrigerant to be condensed decreases, and the discharge pressure of the compressor 1 decreases, so that the reliability of the refrigeration apparatus and the compressor 1 can be ensured without stopping the operation of the compressor 1. .

Embodiment 3 Next, a third embodiment of the present invention will be described with reference to the drawings. FIG. 4 shows the third embodiment.
FIG. 2 is a system diagram showing the configuration of FIG. In this figure, the same or corresponding parts as those in FIG. The difference from FIG. 1 is that a capacity control unit for increasing or decreasing the refrigeration capacity is provided in the compressor, and when the above-mentioned boundary condition is exceeded, the capacity control unit is controlled by the control device to reduce the refrigeration capacity of the compressor by a predetermined value. It is the point which did so. That is, in FIG. 4, reference numeral 11 denotes a capacity control unit for increasing or decreasing the refrigerating capacity of the compressor 1.

In such a configuration, when the discharge pressure of the compressor 1 becomes equal to or higher than the line E or C in FIG.
Operates the capacity control unit 11 to ensure the reliability of the refrigerating apparatus and the compressor, and reduces the refrigerating capacity of the compressor 1 by a predetermined value. As a result, the amount of circulating refrigerant to be condensed decreases, and the discharge pressure of the compressor 1 decreases, so that the reliability of the refrigeration apparatus and the compressor 1 can be ensured without stopping the operation of the compressor 1. .

Embodiment 4 FIG. Next, a fourth embodiment of the present invention will be described. The configuration may be any of the system diagrams in FIG. 1, FIG. 3, and FIG. That is, in this embodiment, the condenser blower 3 is operated at full speed before the discharge pressure of the compressor 1 reaches the line E in FIG. For example, ambient temperature 3
The relationship between the discharge pressure and the suction pressure at 5 ° C. is indicated by the line G in FIG. 2, and when the discharge pressure of the compressor becomes equal to or higher than the line G, the controller 8 operates the condenser blower 3 at full speed.
By doing so, it is possible to prevent a sudden rise in the discharge pressure of the compressor 1 beforehand. Therefore, by performing this in conjunction with each of the above-described embodiments, the reliability of the refrigeration apparatus and the compressor is further improved. Can be improved.

[0022]

The refrigerating apparatus according to the present invention comprises: a compressor;
A condenser for exchanging heat by exchanging the refrigerant discharged from the compressor with air by blowing air from the condenser blower and a condensing device, a throttle device for decompressing the liquid refrigerant condensed by the condenser, and evaporating the depressurized refrigerant, A refrigeration system comprising an evaporator for sucking a gas refrigerant into the compressor, and a detecting device for detecting a discharge pressure and a suction pressure of the compressor or a condensation temperature of the condenser or an evaporation temperature of the evaporator in a refrigeration system. And a control device for stopping the compressor when the discharge pressure or the condensation temperature detected by the detection device exceeds a boundary condition for ensuring reliability determined based on the suction pressure or the evaporation temperature. In addition, it is possible to ensure the reliability of the refrigeration apparatus and the compressor at a high compression ratio operation.

The refrigerating apparatus according to the present invention further includes a detecting device for detecting a discharge pressure and a suction pressure of a compressor, a condensing temperature of a condenser or an evaporating temperature of an evaporator, and a discharge pressure or a pressure detected by the detecting device. When the condensing temperature exceeds the boundary condition for ensuring reliability determined based on the suction pressure or the evaporating temperature, the control device operates the condenser blower at full speed and stops the compressor. The discharge pressure can be quickly reduced while the machine is stopped, and the restart of the refrigeration system can be facilitated, so that the reliability of the refrigeration system and the compressor can be improved.

The refrigerating apparatus according to the present invention also includes a bypass circuit for connecting the discharge side and the suction side of the compressor, an on-off valve provided in the bypass circuit and normally closed, and a compressor for the compressor. A detector for detecting the discharge pressure and the suction pressure, the condensation temperature of the condenser, or the evaporation temperature of the evaporator, and ensuring the reliability that the discharge pressure or the condensation temperature detected by the detection device is determined based on the suction pressure or the evaporation temperature. When the boundary condition is exceeded, the control unit opens the on-off valve while the compressor is running, so that the compressor continues to operate while ensuring the reliability of the refrigeration system and the compressor. be able to.

The refrigerating apparatus according to the present invention also has a capacity control device for increasing and decreasing the refrigerating capacity of the compressor, and a detecting device for detecting a discharge pressure and a suction pressure of the compressor, a condensing temperature of the condenser or an evaporating temperature of the evaporator. When the discharge pressure or the condensing temperature detected by the detecting device exceeds the boundary condition for securing reliability determined based on the suction pressure or the evaporating temperature, the capacity control device is operated to reduce the refrigerating capacity of the compressor. Since the control device is provided with the control device for reducing the pressure, the operation of the compressor can be continued while ensuring the reliability of the refrigerating device and the compressor.

The refrigerating apparatus according to the present invention further comprises a detecting device for detecting a discharge pressure and a suction pressure of a compressor, a condensing temperature of a condenser or an evaporating temperature of an evaporator, and a discharge pressure or a pressure detected by the detecting device. Before the condensing temperature reaches the boundary condition for ensuring reliability determined based on the suction pressure or the evaporating temperature, a control device that operates the condenser blower at full speed with the compressor operated is provided. A sudden increase in the discharge pressure of the compressor can be prevented beforehand, and the operation of the compressor can be continued while ensuring the reliability of the refrigerating device and the compressor.

In the refrigerating apparatus according to the present invention, the boundary condition for ensuring reliability is set such that the relationship between the discharge pressure and the suction pressure of the compressor becomes a straight line or a quadratic curve. It becomes easy and the reliability of the refrigerating device and the compressor can be improved.

[Brief description of the drawings]

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

FIG. 2 is a characteristic diagram showing a relationship between a discharge pressure and a suction pressure of a compressor.

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

FIG. 4 is a system diagram showing a configuration of a third embodiment of the present invention.

FIG. 5 is a system diagram showing a configuration of a conventional refrigeration apparatus.

FIG. 6 is a characteristic diagram showing a relationship between a discharge pressure and a suction pressure of a compressor in a conventional refrigeration system.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Compressor, 2 condenser, 3 condenser blower, 4 throttling device, 5 evaporator, 6 discharge pressure sensor, 7 suction pressure sensor, 8 control device, 9 bypass circuit, 10 on-off valve, 11 capacity control part.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Hideki Ishikawa 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsui Electric Co., Ltd. (72) Inventor Hirofumi Haraigawa 2-6-1 Otemachi, Chiyoda-ku, Tokyo No. Mitsubishi Electric Engineering Co., Ltd. (72) Inventor Hiromitsu Moriyama 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsui Electric Co., Ltd. (72) Koichi Higashi 2-6-1 Otemachi, Chiyoda-ku, Tokyo No. Mitsubishi Electric Engineering Co., Ltd. (72) Inventor Hajime Fujimoto 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation (72) Inventor Masaaki Sugawa 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation (72) Inventor Masao Kawasaki 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation

Claims (8)

[Claims] 1. A compressor, a condenser for exchanging heat discharged from the compressor by air with air from a blower for the condenser to condense the refrigerant, and a throttle device for decompressing the liquid refrigerant condensed by the condenser. An evaporator for evaporating the depressurized refrigerant and sucking the gas refrigerant into the compressor, wherein a refrigerating apparatus constituting a refrigeration cycle includes a discharge pressure and a suction pressure of the compressor or a condensation temperature of the condenser. Alternatively, a detecting device for detecting the evaporating temperature of the evaporator, and when the discharge pressure or the condensing temperature detected by the detecting device exceeds a boundary condition for securing reliability determined based on the suction pressure or the evaporating temperature, A refrigeration apparatus comprising: a control device for stopping the compressor. 2. A compressor, a condenser for exchanging heat of air discharged from the compressor with air from a blower for the condenser and exchanging heat with the air, and a throttle device for decompressing the liquid refrigerant condensed by the condenser. An evaporator for evaporating the depressurized refrigerant and sucking the gas refrigerant into the compressor, wherein a refrigerating apparatus constituting a refrigeration cycle includes a discharge pressure and a suction pressure of the compressor or a condensation temperature of the condenser. Alternatively, a detecting device for detecting the evaporating temperature of the evaporator, and when the discharge pressure or the condensing temperature detected by the detecting device exceeds a boundary condition for securing reliability determined based on the suction pressure or the evaporating temperature, A refrigeration apparatus comprising: a control device that operates a condenser blower at full speed and stops the compressor. 3. A compressor, a condenser for exchanging heat from air discharged from the compressor by air from a blower for the condenser and exchanging heat with the air, and a throttle device for decompressing the liquid refrigerant condensed by the condenser. An evaporator that evaporates the depressurized refrigerant and sucks the gas refrigerant into the compressor, and in a refrigeration system that constitutes a refrigeration cycle, a bypass circuit that couples a discharge side and a suction side of the compressor; An on-off valve provided in the bypass circuit and normally closed, a detecting device for detecting a discharge pressure and a suction pressure of the compressor, a condensing temperature of the condenser, or an evaporating temperature of the evaporator; When the discharge pressure or the condensing temperature detected by the detecting device exceeds the boundary condition for securing reliability determined based on the suction pressure or the evaporating temperature, the opening and closing of the compressor in the operating state of the compressor. A refrigeration system comprising: a control device for opening a valve. 4. A compressor, a condenser for exchanging heat with air discharged from the compressor by air from a blower for the condenser to condense the refrigerant, and a throttle device for decompressing the liquid refrigerant condensed by the condenser. An evaporator for evaporating a depressurized refrigerant and sucking a gas refrigerant into the compressor, wherein in a refrigeration system constituting a refrigeration cycle, a capacity control device for increasing or decreasing the refrigerating capacity of the compressor; A detecting device for detecting a discharge pressure and a suction pressure of the machine or a condensation temperature of the condenser or an evaporation temperature of the evaporator; and a discharge pressure or a condensation temperature detected by the detection device based on the suction pressure or the evaporation temperature. A control device for operating the capacity control device when the determined reliability ensuring boundary condition is exceeded, and reducing the refrigerating capacity of the compressor. Refrigeration equipment. 5. A compressor, a condenser for exchanging heat of air discharged from the compressor with air by a blower from a condenser blower and condensing the refrigerant, and a throttle device for decompressing the liquid refrigerant condensed by the condenser. An evaporator for evaporating the depressurized refrigerant and sucking the gas refrigerant into the compressor, wherein a refrigerating apparatus constituting a refrigeration cycle includes a discharge pressure and a suction pressure of the compressor or a condensation temperature of the condenser. Alternatively, a detecting device for detecting the evaporating temperature of the evaporator, and before the discharge pressure or the condensing temperature detected by the detecting device reaches the boundary condition for ensuring reliability determined based on the suction pressure or the evaporating temperature, A refrigerating apparatus comprising: a control device for operating the condenser blower at full speed in an operating state of the compressor. 6. The full-speed operation of the condenser blower is performed in a region where the discharge pressure of the compressor exceeds the discharge pressure corresponding to the suction pressure of the compressor at a predetermined ambient temperature within a range not reaching the boundary condition. The refrigeration apparatus according to claim 5, wherein: 7. The refrigeration system according to claim 1, wherein the boundary condition is set such that the relationship between the discharge pressure and the suction pressure of the compressor becomes a straight line. apparatus. 8. The boundary condition according to claim 1, wherein the relationship between the discharge pressure and the suction pressure of the compressor is set to be a quadratic curve. Refrigeration equipment.