JPH11230070A - Compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a low stage side compression part of a compressor for compressing refrigerant at multistages from being abnormally increased, by using a plurality of compression parts. SOLUTION: In a compressor C, an electric motor 2 and a compression element 3 to be driven by the electric motor 2 are provided in a single closed container 1, and this compression element 3 is constituted of a low stage side compression part 52 and a high stage side compression part 51, and refrigerant is sequentially compressed at multistages. A communication passage for communicating the discharge side of the low stage side compression part 52 with the inside of the closed container or the discharge side of the high stage side compression part 51 is provided. A check valve 33 taking the discharging side direction of the closed container 1 or the high stage side compression part 51 as the normal direction is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compressor for compressing a refrigerant in multiple stages using a plurality of compression units.

[0002]

2. Description of the Related Art Conventionally, refrigeration systems used in refrigerators, air conditioners, and the like include rotary cylinders and rollers rotating inside the cylinders, respectively, as disclosed in Japanese Patent Publication No. 7-30743 (F04C23 / 00). The rotary type compressor which accommodated two compression parts consisting of the same in the same closed container is adopted. Then, each compression section of the compressor is made into a low-stage compression section and a high-stage compression section, and the refrigerant gas compressed in one stage by the low-stage compression section is sucked into the high-stage compression section, thereby compressing the refrigerant in multiple stages. It has a configuration.

[0003] The use of such a compressor has the advantage that a high compression ratio can be obtained while suppressing the torque fluctuation per compression.

[0004]

However, in the above-described multi-stage compressor having the low-stage compression section and the high-stage compression section, the amount of intake air to be taken into the low-stage compression section and the high-stage compression section is determined. Therefore, when the compressor is started up, when the compressor is pulled down, or when liquid compression occurs, the discharge pressure in the low-stage compression section abnormally increases. As a result, there has been a problem that the load on the compressor becomes excessive and the compressor is damaged.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional technical problem, and a plurality of compression sections are used to compress refrigerant in a multi-stage manner. The purpose is to prevent the.

[0006]

The compressor according to the present invention includes an electric motor and a compression element driven by the electric motor in a single hermetically sealed container. It is constituted by a high-stage compression section and sequentially compresses the refrigerant in multiple stages, and a communication path communicating between the discharge side of the low-stage compression section and the closed vessel, or the discharge side of the high-stage compression section. Provided,
In the communication passage, a check valve is provided in which the forward direction is in the discharge side of the high-stage compression unit in the closed vessel.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a refrigerant circuit diagram of a multi-stage compression refrigeration system R using a compressor C according to the present invention, FIG. 2 is a longitudinal side view of the compressor C of the present invention, and FIG. 3 is a low-stage side of the compressor C of the present invention. 3A and 3B are enlarged cross-sectional views of the vicinity of a communication path 34 that communicates the compression section and the discharge side of the high-stage compression section.

First, in FIG. 2, reference numeral 1 denotes a single closed container, and an electric motor (brushless DC motor or A
A compression element 3 rotatably driven by the electric motor 2 is accommodated in the lower side. The airtight container 1 contains the electric motor 2 and the compression element 3 in a preliminarily divided into two parts and is sealed by high frequency welding or the like.

The electric motor 2 includes a stator 4 fixed to the inner wall of the closed casing 1 and a rotor 5 supported inside the stator 4 so as to be rotatable around a rotation shaft 6. . The stator 4 includes a stator winding 7 that applies a rotating magnetic field to the rotor 5. W1 and W2 are balance weights attached to the upper and lower surfaces of the rotor 5, respectively.

The compression element 3 has a first rotary cylinder 9 and a second rotary cylinder 10 separated by an intermediate partition plate 8. Eccentric portions 11 and 12 that are driven to rotate by the rotating shaft 6 are attached to the cylinders 9 and 10, respectively. The eccentric portions 11 and 12 are 180 degrees out of phase with each other.

Reference numerals 13 and 14 denote a first roller and a second roller which rotate in the cylinders 9 and 10, respectively, and rotate in the cylinder by rotation of the eccentric portions 11 and 12, respectively. 15,
Reference numeral 16 denotes a first frame and a second frame, respectively. The first frame 15 forms a closed compression space of the cylinder 9 between the first frame 15 and the intermediate partition plate 8, and the second frame 16 is Similarly, a closed compression space of the cylinder 10 is formed between the cylinder 10 and the intermediate partition plate 8. The first frame 15 and the second frame 16 are respectively provided with bearing portions 17, 1 that rotatably support the lower portion of the rotary shaft 6.
8 is provided.

The upper cylinder 9, the eccentric portion 11, the roller 13, the vanes (not shown) for dividing the inside of the cylinder 9 into a high-pressure chamber and a low-pressure chamber, and the like constitute a high-stage compression section 51. Cylinder 10, eccentric part 12, roller 14
And a vane (not shown) that partitions the inside of the cylinder 10 into a high-pressure chamber and a low-pressure chamber, and the like, and the low-stage compression section 52 is configured.

The displacement volume of the low-stage compression section 52 is D
1. Assuming that the excluded volume of the high-stage compression section 51 is D2, the excluded volume ratio D2 / D1 is set in the range of 0.35 ± 0.15.

Reference numeral 19 denotes a discharge muffler, and the first frame 1
5 is attached. The cylinder 9 and the discharge muffler 19 communicate with each other through a discharge hole (not shown) provided in the first frame 15.

On the other hand, a recess 21 is provided in the second frame 16, and the recess 21 is closed by a lid 26 and a bolt 27 is provided.
By being fixed to the cylinder 10 integrally with the second frame 16 at, an inflatable silencer 28 is formed inside. The second frame 16 is provided with a discharge port 29 that communicates between the inside of the cylinder 10 and the inside of the recess 21.

The second frame 16 is located at the lowermost part in the closed container 1, and its periphery is an oil reservoir 30 for storing lubricating oil. As a result, the periphery of the second frame 16 is filled with the lubricating oil.
There is no danger that the high-pressure gas in the sealed container 1 leaks into the expansion type silencer 28, and a decrease in performance due to a decrease in the amount of circulating refrigerant can be prevented.

The discharge port 29 communicates with a pipe 31 drawn out of the closed vessel 1, and this pipe 31 is inserted from above into a merger 32 also provided outside the closed vessel 1. 32. Further, an outlet pipe 32 </ b> A at the lower end of the merger 32 is connected to a suction pipe 23 connected to the cylinder 9.

On the other hand, reference numeral 22 denotes a discharge pipe provided on the closed vessel 1, and reference numeral 24 denotes a suction pipe connected to the cylinder 10. Reference numeral 25 denotes a sealed terminal, which is a sealed container 1
To supply electric power to the stator winding 7 of the stator 4 from the outside (not shown are lead wires connecting the sealed terminal 25 and the stator winding 7).

Here, the discharge side of the low-stage compression section 52 and the discharge muffler (located on the discharge side of the high-stage compression section 51).
Are communicated with each other by a communication passage 34 penetrating the first frame 15, the cylinder 9, the intermediate partition plate 8 and the cylinder 10. In the communication passage 34, a check valve 33 Is provided. The pressure in the discharge muffler 19 is constantly applied as a back pressure to the check valve 33, whereby the check valve 33 is pressed against the intermediate partition plate 8 to close the communication passage 34, and the discharge pressure of the low-stage compression section 52 is reduced. When the pressure becomes higher than the pressure, the communication passage 34 is opened. That is, the check valve 33 is provided such that the direction of the discharge muffler 19 located on the discharge side of the high-stage compression section 51 is the forward direction.

Next, in the refrigerant circuit of FIG. 1, the discharge pipe 22 of the compressor C constituting the multi-stage compression refrigeration system R
A condenser 36 is connected via a pipe 36 to an inlet of a condenser 37, and an outlet of the condenser 37 is connected to a capillary tube 38 as primary expansion means. This capillary tube 3
The upper portion of the gas-liquid separator 39 is connected to the outlet of 8, and a capillary tube 41 as secondary expansion means is connected to the lower end of the gas-liquid separator 39.

A cooler 42 is connected to the outlet of the capillary tube 41, and a pipe 43 connected to the outlet of the cooler 42 is connected to the suction pipe 24 of the compressor C. Further, a branch pipe 44 is connected to an upper portion of the gas-liquid separator 39, and the branch pipe 44 is inserted into the merger 32 from above and opened inside.

Thus, the refrigeration cycle of the multistage compression refrigeration system R is constituted. And such a multi-stage compression refrigeration system R
A predetermined amount of an HFC refrigerant or an HC refrigerant such as R-134a is sealed in the refrigerant circuit, and an ester oil, an ether oil, an alkylbenzene oil, a mineral oil, or the like is used as a lubricating oil. Is used as a refrigerant,
Ester oil is used as the lubricating oil.

The operation of the above configuration will now be described. When the electric motor 2 is driven, the low-stage compression section 52 draws the refrigerant from the suction pipe 24 and compresses it (one-stage compression).
And is discharged to the pipe 31 through the expansion type silencer 28. The one-stage compressed gas refrigerant discharged to the pipe 31 is sucked from the suction pipe 23 to the high-stage compression part 51 via the merger 32. There, the two-stage compressed gas refrigerant compressed (two-stage compression) is discharged from the discharge hole to the discharge muffler 19, and the discharge muffler 1
9 into the closed container 1.

The discharged two-stage compressed gas refrigerant in the closed vessel 1 is discharged from the discharge pipe 22 to the pipe 36. And
After flowing into the condenser 37, where the heat is released and condensed, the pressure is reduced by the capillary tube 38. Then, it flows into the gas-liquid separator 39, and a part thereof evaporates there.

Thus, the liquid refrigerant is stored at the bottom of the gas-liquid separator 39, and the one-stage expanded saturated gas refrigerant is stored at the top of the gas-liquid separator 39. At this time, the temperature of the saturated gas refrigerant, that is, the gas-liquid separation temperature is −10 ° C. to + 10 ° C.
The throttle amount of the capillary tube 38 is selected so as to be in the range of 25 ° C.

Then, only the liquid refrigerant flows out of the gas-liquid separator 39 toward the capillary tube 41, where the pressure is reduced. Then, it flows into the cooler 42 and evaporates. At this time, the cooler 42 exerts a cooling action by removing heat from the surroundings. Then, the low-temperature gas refrigerant that has exited the cooler 42 returns to the compressor C via the pipe 43, and is sucked again from the suction pipe 24 into the low-stage compression section 52.

On the other hand, the saturated gas refrigerant in the upper part of the gas-liquid separator 39 flows out to the branch pipe 44 and flows into the merger 32 therethrough. Then, after joining with the one-stage compressed gas refrigerant discharged from the low-stage compression part 52, both are sucked from the suction pipe 23 into the high-stage compression part 51 and compressed again.

Here, the compressor C includes a low-stage compression section 52.
When the compressor C is started, when the refrigerating device R is pulled down, or when liquid compression occurs in the low-stage compression unit 52, the low-stage compression is performed. Although the discharge pressure of the side compression section 52 rises, when it becomes higher than the pressure in the discharge muffler 19, the check valve 33 opens the communication passage 34 as described above, and the pressure in the low-stage side compression section 52 is reduced. Escape to 19. As a result, abnormal pressure rise in the low-stage compression section 52 is avoided.

Further, the low-stage compression section 52, the high-stage compression section 51 of the compressor C, the condenser 37, the capillary tube 38,
Gas-liquid separator 39, capillary tube 41 and cooler 4
2 are sequentially connected in a ring to form a refrigeration cycle.
Then, since the saturated gas refrigerant in the gas-liquid separator 39 is sucked into the high-stage compression section 51 together with the refrigerant discharged from the low-stage compression section 52, compared with a single-stage compression refrigeration apparatus, While suppressing the torque fluctuation per compression,
A high compression ratio can be obtained.

Further, the temperature of the gas refrigerant sucked by the high-stage compression section 51 can be reduced, and the input can be reduced. Also, the high-stage compression unit 51
Since the temperature of the discharged gas refrigerant becomes low, even when ester oil is used as the lubricating oil, it is possible to suppress the occurrence of the POE problem and the deterioration of the lubricating characteristics.

Since the liquid refrigerant in the gas-liquid separator 39 flows through the capillary tube 41 and evaporates in the cooler 42, the refrigerating effect on the refrigerant circulation amount is increased, and the efficiency is improved. (See Mollier diagram in FIG. 4).

Here, the excluded volume D1 of the low-stage compression section 52
The relationship between the ratio of the excluded volume D2 of the high-stage side compression section D2 / D1 and the coefficient of performance is shown in FIG. 5, and as is clear from this figure, the coefficient of performance is 30% of the excluded volume ratio D2 / D1. It has a mountain-like characteristic with a peak in the vicinity.

Next, the gas-liquid separation temperature in the gas-liquid separator 39 is changed by changing the throttle amount of the capillary tube 38, and the peak values of the curves in FIG. 5 at each gas-liquid separation temperature are connected as shown in FIG. As a result, a mountain-like characteristic as shown in FIG. 6 or FIG. 7 is obtained.

That is, based on the relation between the gas-liquid separation temperature and the coefficient of performance in the gas-liquid separator 39 shown in FIG. 6 or FIG.
Since the temperature is set in the range of 0 ° C. to + 25 ° C., the coefficient of performance can be remarkably improved as compared with the single-stage compression refrigeration apparatus shown at the bottom of FIG.

As is apparent from FIG. 5, the coefficient of performance has a peak-like characteristic having a peak at around 30% of the excluded volume ratio D2 / D1 of the low-stage compression unit 52 and the high-stage compression unit 51. Becomes In the present invention, the excluded volume ratio D2 / D is used.
Since 1 is set in the range of 0.35 ± 0.15,
The coefficient of performance can be further improved as compared with a single-stage compression refrigeration apparatus, and the efficiency can be improved.

FIG. 8 shows another embodiment of the compressor C. In this figure, components denoted by the same reference numerals as those in FIG. 2 have the same or similar functions. In this case, the communication path 34 directly communicates the discharge side of the low-stage compression section 52 with the inside of the sealed container 1.

According to this configuration, when the compressor C is started, when the refrigeration system R is pulled down, or when liquid compression occurs in the low-stage compression section 52, the discharge pressure of the low-stage compression section 52 is increased. When the pressure rises and becomes higher than the pressure in the closed container 1, the check valve 33 opens the communication passage 34, and releases the pressure in the low-stage compression section 52 into the closed container 1. Thereby, the low-stage compression unit 5
Abnormal pressurization in 2 is avoided beforehand.

Although the embodiment has been described with reference to a two-stage compression type compressor, the present invention is not limited to this, and the present invention is also effective when applied to a three-stage or four-stage compressor.

[0039]

As described above in detail, according to the present invention, an electric motor and a compression element driven by the electric motor are provided in a single hermetic container, and the compression element is provided with a low-stage compression section. In the compressor configured by the high-stage compression section and sequentially compressing the refrigerant in multiple stages, a communication path is provided to communicate the discharge side of the low-stage compression section with the inside of the closed vessel or the discharge side of the high-stage compression section. ,
In the communication passage, a check valve is provided in the closed vessel or in the discharge side of the high-stage compression section as a forward direction, so that when the compressor is started, when the compressor is pulled down, or when the liquid is compressed. In such a situation, if the discharge pressure of the low-stage compression section rises abnormally, the check valve opens the communication passage.

This makes it possible to discharge the refrigerant from the low-stage compression section directly into the closed vessel or to the discharge side of the high-stage compression section, thereby improving the reliability and durability of the compressor. Can be achieved.

[Brief description of the drawings]

FIG. 1 is a refrigerant circuit diagram of a multi-stage compression refrigeration apparatus to which a compressor of the present invention is applied.

FIG. 2 is a vertical sectional side view of the compressor of the present invention.

FIG. 3 is an enlarged sectional view of the vicinity of a communication passage of the compressor of the present invention.

FIG. 4 is a Mollier diagram of a multi-stage compression refrigeration apparatus to which the compressor of the present invention is applied.

FIG. 5 is a diagram showing a relationship between a displacement volume ratio and a coefficient of performance of a low-stage compression section (low-stage compression means) and a high-stage compression section (high-stage compression means) of the compressor of the present invention.

FIG. 6 is a diagram showing a relationship between a gas-liquid separation temperature and a coefficient of performance of a compressor in a gas-liquid separator of a refrigeration apparatus to which the present invention is applied.

FIG. 7 is another diagram showing the relationship between the gas-liquid separation temperature in the gas-liquid separator and the coefficient of performance of the compressor.

FIG. 8 is an enlarged sectional view of the vicinity of a communication passage of a compressor according to another embodiment of the present invention.

[Explanation of symbols]

 C Compressor R Multistage compression refrigeration system 1 Closed vessel 2 Electric motor 3 Compressor 8 Intermediate partition plate 9, 10 Cylinder 13, 14 Roller 19 Discharge muffler 31 Piping 33 Check valve 34 Communication path 42 Cooler 44 Branch pipe 51 Higher side Compression section 52 Low-stage compression section

Claims (1)

[Claims] An electric motor and a compression element driven by the electric motor are provided in a single closed container.
In a compressor configured by a low-stage compression section and a high-stage compression section and sequentially compressing the refrigerant in multiple stages, the discharge side of the low-stage compression section and the inside of the closed container, or the discharge of the high-stage compression section A communication path communicating with the high-pressure side compression section is provided in the closed vessel, or a non-return valve having a discharge side direction of the high-stage compression section as a forward direction is provided in the communication path. Compressor.