JP2002242848A - Refrigerating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigerating device capable of improving safety of a device by preventing pressure within a sealed container of a hermetic compressor from exceeding prescribed pressure. SOLUTION: This refrigerating device 1 is provided with the hermetic compressor 2 for compressing refrigerant, a refrigerant to water heat exchanger 3 for exchanging heat between the refrigerant and water, a pressure reducing device 4 for expanding the refrigerant and reducing pressure of the refrigerant, an evaporator 5 for exchanging heat between the refrigerant and outside air, an accumulator 6 for performing gas-liquid separation of the refrigerant, a control device 7 for lowering pressure within the container of the hermetic compressor 2 and a pressure detecting device 8 for detecting pressure within the sealed container of the hermetic compressor 2. The control device 7 lowers suction pressure of the hermetic compressor 2 when pressure detected by the pressure detecting device 8 reaches prescribed pressure, and also lowers pressure within the container of the hermetic compressor 2.

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 controlling the pressure in a closed vessel of a hermetic compressor.

[0002]

2. Description of the Related Art Freon refrigerant has conventionally been used as a refrigerant used in a refrigeration system. It has been found that the refrigerant contains a chlorine group and causes ozone layer destruction. As an alternative refrigerant, there is utilization of a carbon dioxide refrigerant which is a natural refrigerant.

[0003] Generally, a hermetic-type compressor having a single-stage refrigerant compression section has a structure in which refrigerant gas compressed to cool an electric motor section is discharged into a closed vessel and discharged to the outside. Is the discharge pressure.

When a carbon dioxide refrigerant is used in a refrigeration system, it requires a higher operating pressure than a chlorofluorocarbon refrigerant.
The pressure in the sealed container of the sealed compressor increases.

In order to reduce the pressure in the hermetic container of the hermetic compressor, the pressure in the hermetic container of the hermetic compressor is reduced by the suction pressure and the discharge pressure. And intermediate pressures.

[0006]

However, when the temperature of the water supplied to the refrigerant-to-water heat exchanger or the temperature of the outside air provided in the refrigeration system rises, the pressure of the refrigerant supplied to the hermetic compressor rises, and There is a problem that the pressure in the closed container of the compressor increases.

An object of the present invention has been made in view of the above circumstances, and prevents the pressure in a sealed container of a sealed compressor from exceeding a predetermined pressure, thereby improving the safety of the device. It is an object of the present invention to provide a refrigeration device that can be operated.

[0008]

According to the first aspect of the present invention,
In the closed vessel, a compression section having a first compression section for compressing the suction refrigerant from the suction pressure to the intermediate pressure and a second compression section for compressing the intermediate pressure refrigerant from the first compression section to the discharge pressure is provided. In a refrigerating apparatus provided with a hermetic compressor in which the pressure in a container is set equal to the intermediate pressure, a pressure detector for detecting the intermediate pressure, and the intermediate pressure detected by the pressure detector reaches a predetermined pressure. In this case, a control device for reducing the suction pressure is provided.

According to a second aspect of the present invention, in the first aspect, the pressure detecting device is a pressure sensor for detecting a pressure in the closed container.

According to a third aspect of the present invention, in the first aspect of the present invention, the pressure detecting device is a temperature detecting device provided on a refrigerant suction side of the pre-stage compression section. is there.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the refrigeration system includes a refrigerant-to-water heat exchanger, and a feedwater temperature detecting device for detecting a feedwater temperature of the refrigerant-to-water heat exchanger. A calculation for calculating an intermediate pressure based on a temperature detected by the supply water temperature detection device by the pressure detection device and a temperature detected by the outside air temperature detection device by providing an outside air temperature detection device for detecting an outside air temperature. It is characterized by having a device.

According to a fifth aspect of the present invention, in the first aspect of the present invention, the control device includes an electric expansion valve provided on a refrigerant suction side of the front-stage compression section. Then, according to the detection result by the pressure detection device,
It has a valve opening control device which controls the valve opening of the electric expansion valve.

According to a sixth aspect of the present invention, in the first aspect of the present invention, the control device includes an electromagnetic on-off valve provided on a refrigerant suction side of the first-stage compression section; A capillary tube provided in parallel with the electromagnetic on-off valve, and a valve opening control device for controlling a valve opening of the electromagnetic on-off valve based on a detection result by the pressure detecting device. It is.

According to a seventh aspect of the present invention, in the first aspect of the present invention, the control device includes an electromagnetic on-off valve provided on a refrigerant suction side of the pre-stage compression section; An electromagnetic expansion valve provided in parallel with the electromagnetic on-off valve, and a valve opening control device for controlling a valve opening of the electromagnetic on-off valve and the electromagnetic expansion valve based on a detection result by the pressure detection device. It is characterized by the following.

According to an eighth aspect of the present invention, in the first aspect of the present invention, the refrigerant is a carbon dioxide refrigerant.

The first to seventh aspects of the present invention have the following effects.

The intermediate pressure in the closed vessel of the closed type compressor is
When the pressure reaches the predetermined pressure, the suction pressure is reduced and the intermediate pressure in the closed container is reduced, so that the pressure of the closed container can be prevented from increasing beyond the predetermined pressure.

Claim 8 has the following operation.

When a carbon dioxide refrigerant that requires a higher operating pressure than the Freon refrigerant is used as the refrigerant, the suction pressure is reduced when the intermediate pressure in the sealed container of the sealed compressor reaches a predetermined pressure. By lowering and lowering the intermediate pressure in the closed container, it is possible to prevent the pressure of the closed container from exceeding a predetermined pressure and increasing.

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

In the refrigerating apparatus according to the embodiment of the present invention, a case will be described in which a carbon dioxide refrigerant which is a natural refrigerant is used as the refrigerant.

[A] First Embodiment FIG. 1 is a refrigerant circuit diagram of a refrigeration apparatus according to a first embodiment of the present invention.

Reference numeral 1 denotes a refrigeration apparatus.
Hermetic compressor 2 for compressing the refrigerant, refrigerant-to-water heat exchanger 3 for exchanging heat between the refrigerant and water, decompressor 4 for expanding and decompressing the refrigerant, evaporator 5 for exchanging heat between the refrigerant and the outside air, An accumulator 6 for performing gas-liquid separation and a control device 7 for controlling a refrigerant suction pressure of the hermetic compressor 2 are provided.

The refrigerating apparatus 1 includes a hermetic compressor 2
The control device 7 controls the refrigerant suction pressure of the hermetic compressor 2 based on the detection result of the pressure detection device 8.

The control device 7 includes an electric expansion valve 9 and a valve opening control device 10 for controlling the opening of the valve. The valve opening control device 10 controls the valve opening of the electric expansion valve 9. And controls the refrigerant suction pressure of the hermetic compressor 2. Pressure detector 8
Has a pressure sensor 11 for detecting the pressure in the closed container of the closed compressor 2.

As shown in FIG. 2, the hermetic compressor 2 has a hermetically sealed container 12 in which a motor 13
And a compression unit 14. The compression section 14 includes a first-stage compression section 15 and a second-stage compression section 16. The front-stage compression section 15 has a refrigerant suction port 15a and a refrigerant discharge port 15b.
And a discharge port 15c for discharging the refrigerant into the closed container 12, and a suction port 16a and a discharge port 16b for the refrigerant are provided in the rear compression section 16. The discharge port 15 b of the front compression unit 15 and the suction port 16 a of the rear compression unit 16 are connected by a connection pipe 17. Suction port 1 of front compression unit 15
A suction pipe 18 for sucking refrigerant to be compressed is provided in 5a, and an electric expansion valve 9 of the control device 7 is provided in the suction port 15a via the suction pipe 18.

A discharge pipe 19 for discharging the compressed refrigerant is provided at a discharge port 16b of the rear compression section 16. One end 20 a of a passage pipe 20 for discharging the refrigerant is connected to the closed container 12, and the other end 20 b of the passage pipe 20 is connected to a connection pipe 17.

The refrigerant sucked from the suction port 15a of the pre-compression unit 15 is compressed by the pre-compression unit 15, and the compressed refrigerant is discharged from the discharge ports 15b, 15 of the pre-compression unit 15.
c. The refrigerant discharged from the suction port 15a of the first-stage compression section 15 passes through the connection pipe 17 and passes through the second-stage compression section 1
6 is sucked through the suction port 16a, compressed by the latter compression section 16, and discharged from the discharge port 16b.

In the closed container 12, the refrigerant discharged from the discharge port 15c becomes an intermediate pressure P3 between the suction pressure P1 and the discharge pressure P2, and the refrigerant having the intermediate pressure P3 is discharged from the passage pipe 20 and is connected to the connection pipe 17. Is sent to the latter-stage compression section 16.

In the above configuration, for example, in summer, the supply water temperature and the outside air temperature of the refrigerant-to-water heat exchanger 3 increase.
Alternatively, one of the temperatures increases. When the refrigeration apparatus 1 is operated in this state, the suction pressure P1 of the refrigerant into the hermetic compressor 2 increases, and the intermediate pressure P3 of the refrigerant compressed in the first-stage compression section 15 increases.

Usually, when the intermediate pressure P3 increases, a compressor protection mechanism (not shown) operates to stop the operation of the compressor.

In the present embodiment, the intermediate pressure P3 is detected by the pressure sensor 11, and when the intermediate pressure P3 reaches a certain predetermined pressure, the valve opening of the electric expansion valve 9 is controlled by the valve opening control device 10. Then, the suction pressure P1 of the refrigerant into the hermetic compressor 2 is reduced, and the intermediate pressure P3 is reduced. Therefore, the intermediate pressure P3 of the sealed container 12 does not increase beyond the predetermined pressure, and the compressor protection mechanism (not shown) does not operate, so that the compressor can be continuously operated.

[B] Second Embodiment FIG. 3 is a refrigerant circuit diagram of a refrigeration apparatus according to a second embodiment of the present invention. In the second embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

The control device 7 comprises a parallel circuit of an electromagnetic on-off valve 21 and a capillary tube 22 and a valve opening control device 23 for controlling the valve opening of the electromagnetic on-off valve 21. When the intermediate pressure P3 is equal to or lower than a predetermined pressure, the valve opening control device 23 opens the electromagnetic on-off valve 21. When the intermediate pressure of the refrigerant reaches the predetermined pressure, the electromagnetic on-off valve 21 is closed and the refrigerant is transferred to the capillary tube. 22 and the suction pressure P
1 to reduce the intermediate pressure P3 in the closed container 12.

Thus, it is possible to prevent the intermediate pressure P3 in the sealed container 12 from exceeding a predetermined pressure and increasing.

[C] Third Embodiment FIG. 4 is a refrigerant circuit diagram of a refrigeration apparatus according to a third embodiment of the present invention. In the third embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

The control device 7 controls a parallel circuit of the electromagnetic on-off valve 24 and the electric expansion valve 25, and a valve opening control device 26 for controlling the valve opening of the electromagnetic on-off valve 24 and the valve opening of the electric expansion valve 25. It is composed of When the intermediate pressure P3 of the refrigerant is equal to or lower than a predetermined pressure, the electromagnetic opening / closing valve 2
4, when the intermediate pressure P3 reaches a predetermined pressure, the electromagnetic on-off valve 24 is closed and the refrigerant is bypassed to the electric expansion valve 25, the valve opening of the electric expansion valve 25 is controlled, and the suction pressure P1 is reduced. The intermediate pressure P3 in the closed container 12 is reduced.

Thus, it is possible to prevent the intermediate pressure P3 in the sealed container 12 from exceeding a predetermined pressure and increasing.

[D] Fourth Embodiment FIG. 5 is a refrigerant circuit diagram of a refrigeration apparatus according to a fourth embodiment of the present invention. In the fourth embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. Since the suction pressure P1 of the refrigerant is proportional to the suction temperature, and the suction pressure P1 is proportional to the intermediate pressure P3, the pressure detection device 8 is connected to the refrigerant temperature detection device 27 that detects the temperature of the suction refrigerant of the hermetic compressor 2. There may be.

[E] Fifth Embodiment FIG. 6 is a refrigerant circuit diagram of a refrigeration apparatus according to a fifth embodiment of the present invention. In the fourth embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. The pressure detection device 7 includes a supply water temperature detection device 28 that detects the temperature of the supply water flowing into the refrigerant-to-water heat exchanger 3, an outside air temperature detection device 29 that detects the outside air temperature, and an intermediate pressure based on the detected temperatures. An arithmetic unit 30 for calculating P3 may be used.

Although the present invention has been described based on one embodiment, the present invention is not limited to this.

[0042]

According to the present invention, when the pressure in the closed container reaches a predetermined pressure, the suction pressure is reduced and the pressure in the container is reduced, so that the pressure in the closed container increases beyond the predetermined pressure. To prevent. Therefore, the refrigeration system is safely driven.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a first embodiment of a refrigeration apparatus according to the present invention.

FIG. 2 is a cross-sectional view of the hermetic compressor.

FIG. 3 is a circuit diagram showing a refrigeration apparatus according to a second embodiment of the present invention.

FIG. 4 is a circuit diagram showing a refrigeration apparatus according to a third embodiment of the present invention.

FIG. 5 is a circuit diagram showing a fourth embodiment of the refrigeration apparatus according to the present invention.

FIG. 6 is a circuit diagram showing a refrigeration apparatus according to a fifth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Refrigeration apparatus 2 Hermetic compressor 3 Refrigerant-water heat exchanger 4 Decompressor 5 Evaporator 6 Accumulator 7 Control device 8 Pressure detection device 9 Electric expansion valve (Control device) 10 Valve opening control device (Control device) 11 Pressure Sensor (pressure detection device) 12 Closed container 13 Electric motor unit 14 Compression unit 15 Front compression unit 15a Suction port 15b Discharge port 15c Discharge port 16 Rear compression unit 16a Suction port 16b Discharge port 21 Electromagnetic open / close valve (control device) 22 Capillary tube ( Control device) 23 Valve opening control device (control device) 24 Electromagnetic on-off valve (control device) 25 Electric expansion valve (control device) 26 Valve opening control device (control device) 27 Refrigerant temperature detecting device (pressure detecting device) 28 Water supply temperature detecting device (pressure detecting device) 29 Outside air temperature detecting device (pressure detecting device) 30 Computing device (pressure detecting device)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kiyoshi Koyama 1 Otsukicho, Ashikaga, Tochigi Pref. Sanyo Electric Air Conditioning Co., Ltd. (72) Inventor Yoshinori Toya 1 Otsukicho, Ashikaga, Tochigi Pref. (72) Inventor Chiaki Shichiji 1 Otsukicho, Ashikaga, Tochigi Prefecture Sanyo Electric Air Conditioning Co., Ltd. (72) Inventor Masanobu Saito 1st Otsukicho, Ashikaga City, Tochigi Prefecture Sanyo Electric Air Conditioning Co., Ltd. (72) Person Shigeya Ishigaki 1F, Otsuki-cho, Ashikaga-shi, Tochigi Sanyo Electric Air Conditioning Co., Ltd.

Claims (8)

[Claims] 1. A compression section having, in a closed vessel, a first-stage compression section for compressing a suction refrigerant from a suction pressure to an intermediate pressure and a second-stage compression section for compressing the intermediate-pressure refrigerant from the first-stage compression section to a discharge pressure. A refrigerating apparatus provided with a hermetic compressor in which the pressure in the closed vessel is set equal to the intermediate pressure; a pressure detecting device for detecting the intermediate pressure; and the intermediate pressure detected by the pressure detecting device. And a controller that reduces the suction pressure when the pressure reaches a predetermined pressure. 2. The refrigeration apparatus according to claim 1, wherein the pressure detection device is a pressure sensor that detects a pressure in the closed container. 3. The refrigerating apparatus according to claim 1, wherein the pressure detecting device is a temperature detecting device provided on a refrigerant suction side of the pre-stage compression section. 4. The refrigeration system includes a refrigerant-to-water heat exchanger, a supply water temperature detection device that detects a supply water temperature of the refrigerant-to-water heat exchanger, and an outside air temperature detection device that detects an outside air temperature. 2. The refrigeration system according to claim 1, further comprising a calculation device that calculates an intermediate pressure based on the temperature detected by the pressure detection device and the temperature detected by the outside air temperature detection device. 3. apparatus. 5. The control device includes an electric expansion valve provided on a refrigerant suction port side of the first-stage compression section, and controls a valve opening of the electric expansion valve based on a detection result by the pressure detection device. The refrigeration apparatus according to any one of claims 1 to 4, further comprising a valve opening control device. 6. The pressure detection device according to claim 1, wherein the control device includes an electromagnetic on-off valve provided on the refrigerant suction port side of the first-stage compression section, and a capillary tube provided in parallel with the electromagnetic on-off valve. The refrigeration apparatus according to any one of claims 1 to 4, further comprising a valve opening control device that controls a valve opening of the electromagnetic on-off valve based on a detection result. 7. The pressure detection device according to claim 1, wherein the control device includes an electromagnetic on-off valve provided on a refrigerant suction side of the pre-stage compression section, and an electromagnetic expansion valve provided in parallel with the electromagnetic on-off valve. The refrigeration apparatus according to claim 1, further comprising a valve opening control device that controls a valve opening of the electromagnetic on-off valve and the electromagnetic expansion valve based on a result of the detection. 8. The refrigeration apparatus according to claim 1, wherein the refrigerant is a carbon dioxide refrigerant.