CN113063235A

CN113063235A - Multistage compression type refrigerating device

Info

Publication number: CN113063235A
Application number: CN202010877999.3A
Authority: CN
Inventors: 金完祚; 金奎英; 郭民熙; 朴相云
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 2019-12-31
Filing date: 2020-08-27
Publication date: 2021-07-02
Anticipated expiration: 2040-08-27
Also published as: CN113063235B; KR102294500B1; KR20210085936A

Abstract

The invention discloses a multistage compression type refrigerating device. The multistage compression type refrigeration apparatus of the present invention comprises: a compression unit configured to compress a refrigerant at a plurality of compression ends; a condensing part connected to the compressing part, the refrigerant passing through the compressing part being condensed by heat exchange; an accumulator connected to the condensing part and storing the liquid refrigerant condensed in the condensing part; a first expansion valve portion provided in a pipe connected to the accumulator and configured to expand the refrigerant discharged from the accumulator; a gas-liquid separation portion that receives the refrigerant passing through the first expansion valve portion and separates into a liquid refrigerant and a gaseous refrigerant, supplying the gaseous refrigerant to the compression portion; a second expansion valve section provided in a pipe connected to the gas-liquid separation section and configured to expand the refrigerant discharged from the gas-liquid separation section; and an evaporation part connected to the gas-liquid separation part and the compression part, and converting the liquid refrigerant discharged from the gas-liquid separation part into a gaseous refrigerant through heat exchange, and the gas-liquid separation part may be disposed downstream of the accumulator.

Description

Multistage compression type refrigerating device

Technical Field

The present invention relates to a multistage compression type refrigeration apparatus.

Background

As a general refrigerating apparatus, a refrigerator (Chiller) can be used. A refrigerator is a large-scale refrigeration system that can provide refrigeration to a large building and uses cold water or antifreeze as a refrigerant for transferring a substance as a heat source.

A chiller is a device that supplies cold water to a demand. In addition, the refrigerator conducts to perform heat exchange between the refrigerant circulating in the refrigerant cycle and the cold water circulating at a demand, thereby cooling the cold water. A refrigerating apparatus using a refrigerator is a facility having a large capacity, and thus can be installed in a large-scale building or the like.

Cold water cooled in a refrigeration apparatus using a refrigerator is supplied to a place where a demand for using an air conditioner or the like is demanded.

The refrigerator unit includes: a compressor for compressing a refrigerant; a condenser for condensing refrigerant compressed in the compressor; an expansion device for decompressing the refrigerant condensed in the condenser; and an evaporator for evaporating the refrigerant decompressed in the expansion device. The refrigerant used in the related art refrigerating apparatus may exchange heat with outside air in the condenser, and may exchange heat with cold water in the evaporator.

The chiller units may be provided in various sizes or capacities. The size or capacity of the refrigerator unit is a concept corresponding to the refrigerating capacity, and thus can be expressed in units of Refrigeration Tons (RT). The refrigerator unit may be manufactured to have various kinds of facilities of freezing tons according to the size of a building or the like in which the refrigerator unit is installed, the capacity of cold water to be circulated, the capacity of an air conditioner, or the like. For example, the chiller unit may be manufactured as a model having a capacity of 200RT, 500RT, 1000RT, 1500RT, 2000RT, 3000RT, etc.

When the compressor of the related art refrigerating apparatus compresses the refrigerant in multiple stages, an Economizer (Economizer) may be installed as a gas-liquid separator that separates the refrigerant in a gas state and the refrigerant in a liquid state.

In addition, in the load control of the conventional refrigerating apparatus, a method of mechanically controlling an Inlet Guide Vane (IGV) of the compressor and a method of controlling a refrigerating capacity by a Hot Gas Bypass (Hot Gas Bypass) are used. In the case of controlling the refrigeration apparatus using only the inlet guide vane, the reduction in the refrigeration efficiency is minimal as compared with other methods, but since the reduction amount of the refrigeration capacity is not large, there is a problem in that it is difficult to cope with the low-load operation having a small value of the refrigeration capacity.

When the load control of the refrigerating apparatus cannot be performed only with the inlet guide vane, the refrigerant of the condenser will be directly transferred to the evaporator via the high-temperature gas bypass, in which case there will be a problem in that the refrigerating efficiency is greatly reduced.

[ Prior art documents ]

[ patent document ]

(patent document 1) Korean laid-open patent publication No. 2019-0006339 (published in 2019 on 1 month and 18 th, title of the invention: refrigerator unit and refrigerator system comprising the same)

Disclosure of Invention

The invention provides a multistage compression type refrigerating apparatus capable of easily controlling the refrigerating capacity of the refrigerating apparatus and minimizing the reduction of the refrigerating efficiency.

It is another object of the present invention to provide a multistage compression type refrigeration apparatus in which the refrigeration capacity can be easily controlled at the time of the minimum load operation of the refrigeration apparatus without using an inlet guide vane or a high-temperature gas bypass.

Objects of the present invention are not limited to the above objects, and other objects and advantages of the present invention, which are not mentioned, can be understood by the following description, and the present invention can be more clearly understood by means of the embodiments of the present invention. Further, it is apparent that the objects and advantages of the present invention can be achieved by the means set forth in the claims and combinations thereof.

The control portion according to the present invention is capable of adjusting the number of actions of the compression end by controlling the control valve portion provided at the piping portion for supplying the gaseous refrigerant to the compression portion having the plurality of compression ends.

In addition, the gas-liquid separation portion according to the present invention sequentially blocks the pipe portion for conveying the gaseous refrigerant from the separation portion having a lower pressure toward the separation portion having a higher pressure.

The multistage compression type refrigeration apparatus according to the present invention comprises: a compression unit that compresses refrigerant at a plurality of compression ends; a condensing part connected to the compressing part, and condensing the refrigerant passing through the compressing part by heat exchange; a first expansion valve portion provided in a pipe for guiding movement of the refrigerant discharged from the condensation portion, for expanding the refrigerant; a gas-liquid separation section having a plurality of separation sections and receiving the refrigerant passing through the first expansion valve section and separating it into a liquid refrigerant and a gaseous refrigerant, supplying the gaseous refrigerant to the compression section; a second expansion valve portion that is provided in a pipe connected to the gas-liquid separation portion and expands the refrigerant discharged from the gas-liquid separation portion; and a control valve portion that is provided in a plurality of pipes that guide the gaseous refrigerant separated from the gas-liquid separation portion to the compression portion, and controls movement of the refrigerant.

Further, a control unit for controlling the operation of the control valve unit may be provided.

In addition, the gas-liquid separating portion includes a plurality of separating portions for separating the delivered refrigerant into the liquid refrigerant and the gaseous refrigerant, and the number of separating portions provided to the gas-liquid separating portion may be smaller than the number of compressing ends provided to the compressing portion.

In addition, the control part may sequentially block pipes connected to the separation parts from the separation part having the lowest pressure to the separation part having the highest pressure, and may adjust a cooling capacity.

In addition, the compressing part may include: a first compression unit that compresses the refrigerant sent through the evaporation unit at a plurality of compression ports; and a second compression part connected to the first compression part and compressing the refrigerant passing through the first compression part and compressed at a plurality of compression ends.

In addition, the first compression part may include: a first compression end for compressing the refrigerant transmitted through the evaporation unit; and a second compression end disposed downstream of the first compression end and compressing the refrigerant compressed at the first compression end again.

In addition, the second compression part may include: a third compression end that compresses the refrigerant sent through the second compression end; a fourth compression end disposed downstream of the third compression end and compressing the refrigerant compressed in the third compression end again; and a fifth compression end disposed downstream of the fourth compression end and compressing the refrigerant compressed in the fourth compression end again.

In addition, the gas-liquid separation portion may include: a first separation section connected to the first expansion valve section; a second separation portion that is provided downstream of the first separation portion and separates the refrigerant sent thereto from the first separation portion into a gaseous refrigerant and a liquid refrigerant; a third separation portion that is provided downstream of the second separation portion and separates the refrigerant sent from the second separation portion into a gaseous refrigerant and a liquid refrigerant; and a fourth separation portion that is provided downstream of the third separation portion and separates the refrigerant sent thereto from the third separation portion into a gaseous refrigerant and a liquid refrigerant.

In addition, the control valve part may include a first operation valve provided at a first supply pipe for guiding the gaseous refrigerant separated from the first separation part to an inlet of the fifth compression port and operated according to a control signal of the control part to open and close the pipe.

In addition, the control valve portion may further include a second operation valve provided in a second supply pipe that guides the gaseous refrigerant separated from the second separation portion to the inlet of the fourth compression port and operates to open and close the pipe in accordance with a control signal of the control portion.

In addition, the control valve portion may further include a third operation valve provided in a third supply pipe for guiding the gaseous refrigerant separated from the third separation portion to the inlet of the third compression port and operated according to a control signal of the control portion to open and close the conduit.

In addition, the control valve portion may further include a fourth operation valve provided in a fourth supply pipe for guiding the gaseous refrigerant separated from the fourth separation portion to the inlet of the second compression end and operated according to a control signal of the control portion to open and close the conduit.

In order to reduce the cooling capacity, the control unit may operate the fourth operating valve to block the fourth supply pipe, and may operate the third operating valve, the second operating valve, and the first operating valve in this order to block the duct, as necessary.

In addition, the present invention may further include an accumulator connected to the condensing portion and storing the liquid refrigerant condensed in the condensing portion, and the first expansion valve portion expands the refrigerant discharged from the accumulator and may be provided at the first pipe connecting the accumulator and the gas-liquid separating portion.

In addition, the second inflation valve portion may include: a first valve connected to a second pipe for connecting the first separation part and the second separation part; a second valve connected to a third pipe for connecting the second separation part and the third separation part; a third valve connected to a fourth pipe for connecting the third separation part and the fourth separation part; and a fourth valve connected to a fifth pipe for connecting the fourth separation part and the evaporation part.

The control portion according to the present invention controls the control valve portion provided in the piping portion that supplies the gaseous refrigerant to the compression portion having the plurality of compression ends, so that the cooling capacity of the cooling apparatus can be easily controlled, and the reduction in cooling efficiency can be minimized.

In addition, the gas-liquid separation portion according to the present invention sequentially blocks the pipe portion that transports the gaseous refrigerant from the separation portion having a lower pressure toward the separation portion having a higher pressure, and thus can respond stepwise to a partial load of the refrigeration capacity.

In addition, the refrigerant that moves from the condensing portion to the evaporator according to the present invention passes through the separating portions of the plurality of gas-liquid separating portions and sequentially expands, thereby reducing noise during partial load operation.

In addition to the above effects, specific effects of the present invention will be described while specific matters for carrying out the present invention are described.

Drawings

Fig. 1 is a block diagram showing the main structure of a multistage compression type refrigeration apparatus according to an embodiment of the present invention.

Fig. 2 is a block diagram illustrating a compression section according to an embodiment of the present invention.

Fig. 3 is a block diagram illustrating an accumulator and a gas-liquid separation portion according to an embodiment of the present invention.

Fig. 4 is a block diagram illustrating a state in which the gaseous refrigerant separated from the gas-liquid separation portion according to an embodiment of the present invention moves toward the compression portion.

Fig. 5 is a block diagram illustrating a state in which a compression part is cooled using a refrigerant discharged from a condensation part according to an embodiment of the present invention.

Fig. 6 is a perspective view showing a multistage compression type refrigerating apparatus according to an embodiment of the present invention.

Fig. 7 is a P-H diagram when the gas-liquid separation section according to the embodiment of the present invention is operated in its entirety.

Fig. 8 is a P-H diagram of a fourth separator according to an embodiment of the present invention in a non-operating state.

Fig. 9 is a P-H diagram of a state in which the third separator and the fourth separator are not operating according to an embodiment of the present invention.

Fig. 10 is a P-H diagram of the second separator, the third separator, and the fourth separator in a non-operating state according to an embodiment of the present invention.

Fig. 11 is a P-H diagram when all of the gas-liquid separation section does not operate according to an embodiment of the present invention.

Wherein the reference numerals are as follows:

1: multistage compression type refrigerating device

10: the compression section 20: first compression portion 22: first compression end 24: second compression end

30: second compression portion 32: third compression end 34: fourth compression end 36: fifth compression end

40: condensation section

60: liquid storage device

70: first expansion valve portion

80: gas-liquid separation section 82: first separated portion 84: second separating portion 86: third separation part

88: a fourth separating part

90: second expansion valve portion 92: first valve 94: second valve 96: third valve 98: fourth valve

100: evaporation part

110: duct portion 111: first tube 112: second pipe 113: third pipe 114: fourth pipe

115: fifth pipe 116: first cooling pipe 117: second cooling pipe 118: a first exhaust pipe

119: second discharge pipe 120: first supply pipe 122: second supply pipe 124: third supply pipe

126: fourth supply pipe

C: total refrigeration capacity

R1: first reduced refrigeration capacity C1: first cooling capacity

R2: second reduced refrigeration capacity C2: second cooling capacity

R3: third reduced refrigeration capacity C3: third cooling capacity

R4: fourth reduced refrigeration capacity C4: fourth cooling capacity

Detailed Description

The foregoing objects, features and advantages will be described in detail with reference to the accompanying drawings, whereby those skilled in the art can easily embody the technical idea of the present invention. In describing the present invention, when it is judged that a detailed description of a known technology related to the present invention would obscure the gist of the present invention, a detailed description thereof will be omitted. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals denote the same or similar structural elements.

Although the first, second, etc. constituent elements are used for explaining a plurality of structural elements, these constituent elements are not limited to these terms. These terms are used only for distinguishing one constituent element from another constituent element, and it is needless to say that the first constituent element may be the second constituent element unless otherwise stated.

Hereinafter, the arrangement of any constituent on "upper (or lower)" or "upper (or lower)" of a constituent element means that any constituent is disposed in contact with the top surface (or bottom surface) of a component, and may also mean that other constituents may be interposed between the constituent element and any constituent disposed above (or below) the constituent element.

In addition, when it is described that a certain constituent element is "connected", "coupled" or "connected" to another constituent element, it is to be understood that the above constituent element may be directly connected or connected to the above other constituent element, another constituent element may be "interposed" between the constituent elements, or each constituent element may be "connected", "coupled" or "connected" by another constituent element.

Throughout the specification, each constituent element may be singular or plural unless otherwise specified.

Furthermore, unless the context clearly dictates otherwise, expressions in the singular include a plurality of expressions. In the present application, the term "composed of … …" or "including" should not be interpreted as including all of the various constituent elements or steps described in the specification, may not include some of the constituent elements or steps, or may be interpreted as further including other constituent elements or steps.

Throughout the specification, when "a and/or B" is referred to, A, B or a and B is indicated unless otherwise stated, and when "C to D" is referred to, C is above and D is below, unless otherwise stated.

Hereinafter, a multistage compression type refrigeration apparatus according to an embodiment of the present invention is explained.

[ multistage compression type refrigerating apparatus ]

As shown in fig. 1, a multistage compression type refrigeration apparatus 1 according to an embodiment of the present invention may include: the compression section 10, the condensation section 40, the accumulator 60, the first expansion valve section 70, the gas-liquid separation section 80, the second expansion valve section 90, the evaporation section 100, the piping section 110, the control valve section 130, and the control section 140.

[ compression part ]

As shown in fig. 1 and 2, the compression unit 10 may be modified in various forms within the technical idea of compressing refrigerant at a plurality of compression ends. The compression part 10 according to an embodiment includes a first compression part 20 and a second compression part 30.

[ first compression part ]

The first compression unit 20 is connected to the evaporation unit 100 via the pipe unit 110, and can be variously modified within the technical idea of receiving the refrigerant via the evaporation unit 100 and then compressing it at a plurality of compression ends.

The first compression part 20 according to an embodiment may include: a first compression end 22 for compressing the refrigerant transmitted through the evaporation unit 100; and a second compression end 24 disposed after (downstream of) the first compression end 22 and compressing the refrigerant compressed by the first compression end 22 again. Although the case where the first compression part 20 performs compression of the refrigerant at two compression ends has been described, it is not limited thereto, and the first compression part 20 according to an embodiment may include a single compression end, or may include more than three compression ends.

The gaseous refrigerant discharged from the evaporation portion 100 moves to the first compression end 22 of the first compression part 20, thereby achieving compression. The second compression end 24 is located rearward (right side in fig. 1) opposite the first compression end 22. The refrigerant that has been compressed in the first compression end 22 will move to the second compression end 24 and be compressed again. .

[ second compression part ]

The second compression part 30 is connected with the first compression part 20, and various types of compressors may be used within the technical idea of compressing the refrigerant passing through the first compression part 20 and compressed in a plurality of compression ends. The second compression part 30 receives and compresses the refrigerant compressed in the first compression part 20, and the first compression part 20 and the second compression part 30 are connected by a pipe-shaped pipe.

The first compression part 20 according to an embodiment includes two compression ends and the second compression part 30 includes three compression ends. However, various modifications are possible, and for example, the first compression part 20 may include three or more compression ends, and the second compression part 30 may include two or four or more compression ends, and the like.

For example, the second compression section 30 includes a third compression end 32, a fourth compression end 34, and a fifth compression end 36. The third compression end 32, the fourth compression end 34, and the fifth compression end 36 are arranged in a line, and sequentially achieve compression of the refrigerant. Such third, fourth and fifth compressing ends 32, 34 and 36 are located inside a case (case) of the second compressing part 30.

The third compression end 32 compresses the refrigerant passing thereto via the second compression end 24. The fourth compression end 34 located rearward of the third compression end 32 is disposed rearward of the third compression end 32 and compresses the refrigerant compressed in the third compression end 32 again. And, the fifth compression end 36 is disposed after the fourth compression end 34, and compresses the refrigerant compressed in the fourth compression end 34 again.

The first compression part 20 is provided with a first compression end 22 and a second compression end 24 for compressing the refrigerant, and the first compression end 22 and the second compression end 24 are rotated by the operation of a motor provided in the first compression part 20, thereby compressing the refrigerant.

The second compression part 30 is also provided with a third compression end 32, a fourth compression end 34, and a fifth compression end 36 for compressing the refrigerant, and the third compression end 32, the fourth compression end 34, and the fifth compression end 36 compress the refrigerant by being rotated by the operation of a motor provided in the second compression part 30.

[ condensation section ]

The condensing part 40 is connected to the compressing part 10 via a connection pipe, and refrigerant passing through the compressing part 10 is condensed by heat exchange. The refrigerant moving from the second compression part 30 to the inlet of the condensation part 40 is in a vapor state, and the refrigerant passing through the condensation part 40 exchanges heat with air or a cryogenic fluid, thereby forming a refrigerant in a liquid state.

[ reservoir ]

Fig. 3 is a block diagram illustrating the accumulator 60 and the gas-liquid separating portion 80 according to an embodiment of the present invention.

As shown in fig. 1 and 3, the accumulator 60 is connected to the condensing portion 40, and may be modified in various forms within the technical idea of having a space for storing the liquid refrigerant condensed in the condensing portion 40. The accumulator 60 receives the liquid refrigerant supercooled by the condenser 40, and stores the liquid refrigerant in the accumulator 60.

For example, the accumulator 60 is provided behind the gas-liquid separation portion 80 and is formed in a cylindrical shape. Since the accumulator 60 is formed in a cylindrical shape, even if the internal pressure is increased by the refrigerant stored inside the accumulator 60, the internal pressure can be easily dispersed by the cylindrical shape, and therefore, the durability of the gas-liquid separation portion 80 can be improved in the accumulator 60.

The accumulator 60 may be disposed between the condensing portion 40 and the gas-liquid separating portion 80, and in some cases, the provision of the accumulator 60 may also be omitted. In the case where the arrangement of the accumulator 60 is omitted, the refrigerant discharged from the condensing portion 40 passes through the first expansion valve portion 70 and is expanded, and then is supplied to the first separating portion 82.

[ gas-liquid separation part ]

The gas-liquid separation portion 80 receives the refrigerant that has passed through the first expansion valve portion 70 and separates the refrigerant into a liquid refrigerant and a gaseous refrigerant, and various modifications are possible within the technical idea of supplying the gaseous refrigerant to the compression portion 10.

Since the gas-liquid separation portion 80 is provided behind the accumulator 60, the installation space for the accumulator 60 and the gas-liquid separation portion 80 can be reduced, and the space utilization rate can be improved. For example, the gas-liquid separation portion 80 and the accumulator 60 may be provided successively in this order inside a cylindrical casing extending in a straight direction.

The gas-liquid separation part 80 and the accumulator 60 are provided in one casing, and the gas-liquid separation part 80 and the accumulator 60 share an outer casing, so that installation costs of the apparatus can be reduced, and the accumulator 60 and the plurality of separation parts can be provided even in a relatively narrow space, so that cooling efficiency can be improved.

A partition wall provided in the vertical direction may be located between the reservoir 60 and the gas-liquid separation portion 80 provided inside one casing, and a partition wall provided in the vertical direction may also be located between the respective separation portions provided in the gas-liquid separation portion 80.

The gas-liquid separation portion 80 may be provided with a plurality of separation portions for separating the refrigerant transferred thereto into a liquid refrigerant and a gaseous refrigerant. In addition, the number of the separation sections provided in the gas-liquid separation section 80 may be less than the number provided in the compression end of the compression section 10.

For example, the compression section 10 of the present invention is provided with five compression ends, and the gas-liquid separation section 80 corresponding to the compression section 10 is provided with four separation sections. The maximum number of the separation sections provided in the gas-liquid separation section 80 is a number obtained by subtracting 1 from the number of the compression ends provided in the compression section 10.

The gas-liquid separation section 80 according to an embodiment of the present invention includes: a first separating portion 82, a second separating portion 84, a third separating portion 86, and a fourth separating portion 88.

The first separation portion 82 is provided downstream of the reservoir 60 with a partition wall interposed therebetween, and is connected to the first expansion valve portion 70. Therefore, the liquid refrigerant in the supercooled state discharged from the accumulator 60 passes through the first valve 92, and moves to the inside of the first separating portion 82 in a state where its volume is expanded with its pressure reduced.

The refrigerant moving to the inside of the first separating portion 82 is separated into a gaseous refrigerant and a liquid refrigerant. The gaseous refrigerant separated from the first separating part 82 moves to the inlet of the fifth compression end 36 and moves to the fifth compression end 36 together with the refrigerant moving from the outlet of the fourth compression end 34 to the inlet of the fifth compression end 36 and is compressed.

The second separating portion 84 is disposed after the first separating portion 82, and separates the refrigerant transferred thereto from the first separating portion 82 into a gaseous refrigerant and a liquid refrigerant.

The second separation portion 84 is provided behind the first separation portion 82 with a partition wall interposed therebetween, and receives the refrigerant passing through the first valve 92 provided in the second expansion valve portion 90. Therefore, the refrigerant in the liquid state discharged from the first separation portion 82 passes through the first valve 92 provided to the second expansion valve portion 90, and moves to the inside of the second separation portion 84 in a state where the pressure thereof is reduced and the volume thereof is expanded.

The refrigerant moved to the inside of the second separation portion 84 is separated into a gaseous refrigerant and a liquid refrigerant. The refrigerant in the gaseous state separated from the second separating part 84 moves to the inlet of the fourth compression end 34 and moves to the fourth compression end 34 together with the refrigerant moving from the outlet of the third compression end 32 to the inlet of the fourth compression end 34 and is compressed.

The third separating portion 86 is provided behind the second separating portion 84 with a partition wall interposed therebetween, and receives the refrigerant passing through the second valve 94 provided in the second expansion valve portion 90. Therefore, the refrigerant in a liquid state discharged from the second separation portion 84 passes through the second valve 94 provided to the second expansion valve portion 90, and moves to the inside of the third separation portion 86 in a state where its pressure is reduced and its volume is expanded.

The refrigerant moved to the inside of the third separation portion 86 is separated into the gaseous refrigerant and the liquid refrigerant. The gaseous refrigerant separated from the third separation part 86 moves to the inlet of the third compression end 32 and moves to the third compression end 32 together with the refrigerant moving from the outlet of the second compression end 24 to the inlet of the third compression end 32 and is compressed.

The fourth separating portion 88 is provided behind the third separating portion 86 with a partition wall interposed therebetween, and receives the refrigerant passing through the third valve 96 provided in the second expansion valve portion 90. Therefore, the refrigerant discharged from the third separating portion 86 to a liquid state passes through the third valve 96 provided in the second expansion valve portion 90, and moves to the inside of the fourth separating portion 88 in a state where its pressure is reduced and its volume is expanded.

The refrigerant moved to the inside of the fourth separating portion 88 is separated into the gaseous refrigerant and the liquid refrigerant. The refrigerant in the gaseous state separated from the fourth separating part 88 moves to the inlet of the second compression end 24 and moves to the second compression end 24 together with the refrigerant moving from the outlet of the first compression end 22 to the inlet of the second compression end 24 and is compressed.

The accumulator 60 and the first separating portion 82, the second separating portion 84, the third separating portion 86, and the fourth separating portion 88 constituting the gas-liquid separating portion 80 are provided in series in this order, and are located inside the single tank (tank) portion.

Further, since the gas-liquid separation portion 80 and the liquid reservoir 60 are integrally manufactured, a compact external configuration can be achieved as compared with a refrigeration apparatus in which the gas-liquid separation portion 80 is provided beside the compression portion 10 in the related art. In addition, since the gas-liquid separating portion 80 is provided in a sump shape together with the accumulator 60, an installation space of the gas-liquid separating portion 80 and the accumulator 60 is reduced, and thus, a greater number of separating portions can be additionally provided compared to the related art, so that the refrigerating efficiency can be improved.

Further, as the number of separation units provided in the gas-liquid separation unit 80 increases, the refrigeration capacity can be significantly improved as compared with the related art. In the present invention, four separation portions are applied to the five-stage refrigeration cycle, thereby improving the refrigeration efficiency.

In the conventional refrigerator, there is a structural limitation in an installation space of the separation portion located above the heat exchanger. However, since the gas-liquid separation portion 80 and the accumulator 60 are provided in an integrated tank form, the problem of the limitation of the installation space can be solved, and the number of the separation portions can be increased, thereby improving the cooling efficiency.

[ first expansion valve section ]

The first separating portion 82 is provided behind the reservoir 60, and the reservoir 60 and the first separating portion 82 may be connected by a first pipe 111. The first expansion valve portion 70 is provided in a first pipe 111, which is a pipe connected to the accumulator 60, and this first expansion valve portion 70 expands and reduces the pressure of the refrigerant discharged from the accumulator 60.

[ second expansion valve section ]

The second expansion valve portion 90 is provided in a pipe connected to the gas-liquid separation portion 80, and various types of expansion valves can be used within the technical idea of expanding the refrigerant discharged from the gas-liquid separation portion 80. The second expansion valve portion 90 according to an embodiment of the invention includes a first valve 92, a second valve 94, a third valve 96, and a fourth valve 98.

The first valve 92 is connected to a second pipe 112 connecting the first separation portion 82 and the second separation portion 84, and expands and decompresses the refrigerant discharged from the first separation portion 82. The refrigerant passing through the first valve 92 moves to the second separation portion 84 along the second pipe 112.

The second valve 94 is connected to a third pipe 113 connecting the second separation portion 84 and the third separation portion 86, and expands and decompresses the refrigerant discharged from the second separation portion 84. The refrigerant passing through the second valve 94 moves to the third separating portion 86 along the third pipe 113.

The third valve 96 is connected to a fourth pipe 114 connecting the third separating portion 86 and the fourth separating portion 88, and expands and decompresses the refrigerant discharged from the third separating portion 86. The refrigerant passing through the third valve 96 moves to the fourth separator 88 along the fourth pipe 114.

The fourth valve 98 is connected to a fifth pipe 115 connecting the fourth separating portion 88 and the evaporation portion 100, and expands and decompresses the refrigerant discharged from the fourth separating portion 88. The refrigerant passing through the fourth valve 98 moves to the evaporation portion 100 along the fifth pipe 115.

[ Evaporation part ]

The evaporation unit 100 is connected to the gas-liquid separation unit 80 and the compression unit 10 via pipes, and various types of evaporation devices can be employed within the technical idea of converting the liquid refrigerant discharged from the gas-liquid separation unit 80 into a gaseous refrigerant by heat exchange. The refrigerant passing through the fourth valve 98 will pass through the evaporation part 100 and be formed into a low temperature gas, and then move to the compression part 10.

[ pipe section ]

The pipe portion 110 is used to connect the main components of the multistage compression refrigeration apparatus 1, and can be variously modified within the technical idea of guiding the movement of the refrigerant. As an example, the duct portion 110 may include: a first pipe 111, a second pipe 112, a third pipe 113, a fourth pipe 114, a fifth pipe 115, a first cooling pipe 116, a second cooling pipe 117, a first discharge pipe 118, and a second discharge pipe 119. In addition, the pipe part 110 may further include a first supply pipe 120, a second supply pipe 122, a third supply pipe 124, and a fourth supply pipe 126 for connecting the gas-liquid separation part 80 and the compression part 10.

The first pipe 111 is a pipe for connecting the reservoir 60 and the first separating portion 82, and may have a shape protruding toward the outside of the reservoir formed integrally by the reservoir 60 and the gas-liquid separating portion 80. Alternatively, the first pipe 111 may be variously modified, and may be provided inside a tank formed integrally with the liquid reservoir 60 and the gas-liquid separation portion 80, for example. A first expansion valve portion 70 is provided on such a first pipe 111.

The second pipe 112 is a pipe for connecting the first and

second separation portions

82 and 84, and may have a shape protruding toward the outside of the sump formed integrally by the first and

second separation portions

82 and 84. Alternatively, the second pipe 112 may be variously modified, and may be provided inside a tank formed integrally by the first and

second separating portions

82 and 84, for example. A first valve 92 is provided in this second pipe 112.

The third pipe 113 is a pipe for connecting the second separation portion 84 and the third separation portion 86, and may have a shape protruding toward the outside of the sump formed integrally by the second separation portion 84 and the third separation portion 86. Alternatively, the third pipe 113 may be variously modified, and may be provided inside a tank formed integrally by the second separating portion 84 and the third separating portion 86, for example. A second valve 94 is provided in this third pipe 113.

The fourth pipe 114 is a pipe for connecting the third separating portion 86 and the fourth separating portion 88, and may have a shape protruding toward the outside of the sump formed integrally by the third separating portion 86 and the fourth separating portion 88. Alternatively, the fourth pipe 114 may be variously modified, and may be disposed inside a tank formed integrally by the third separating portion 86 and the fourth separating portion 88, for example. A third valve 96 is provided on this fourth tube 114.

A fifth pipe 115 is a pipe for connecting the fourth separating portion 88 and the evaporation portion 100, and a second valve 94 is provided in this fifth pipe 115.

[ control valve section ]

The control valve portion 130 is provided on a plurality of pipes for guiding the gaseous refrigerant separated from the gas-liquid separation portion 80 to the compression portion, and various types of valves may be employed within the technical idea of controlling the movement of the refrigerant by acting manually or automatically. The control valve portion 130 according to an embodiment includes a first operating valve 132, a second operating valve 134, a third operating valve 136, and a fourth operating valve 138.

The first actuating valve 132 is provided on the first supply pipe 120 for guiding the gaseous refrigerant separated from the first separating part 82 to the inlet of the fifth compression end 36, and is actuated according to a control signal of the control part 140, thereby opening and closing the first supply pipe 120.

The second actuating valve 134 is provided in the second supply pipe 122 for guiding the gaseous refrigerant separated from the second separating part 84 to the inlet of the fourth compression end 34, and is actuated according to a control signal of the control part 140 to open and close the second supply pipe 122.

The third operation valve 136 is provided in the third supply pipe 124 for guiding the gaseous refrigerant separated from the third separation part 86 to the inlet of the third compression end 32, and operates according to a control signal of the control part 140 to open and close the third supply pipe 124.

The fourth operation valve 138 is provided in the fourth supply pipe 126 for guiding the gaseous refrigerant separated from the fourth separating unit 88 to the inlet of the second compression end 24, and operates according to a control signal of the control unit 140 to open and close the fourth supply pipe 126.

The first, second, third, and

fourth operating valves

132, 134, 136, and 138 may be operated manually or automatically in response to a control signal from the control unit 140.

[ control section ]

The control unit 140 may employ various types of control devices within the technical idea of controlling the operation of the control valve unit 130. Since the control part 140 according to an embodiment sequentially blocks the pipes connected to the separation parts from the separation part having the lowest pressure toward the separation part having the highest pressure, the cooling capacity can be adjusted.

The control unit 140 may reduce the cooling capacity by operating the fourth operating valve 138 to block the fourth supply pipe 126, and may block the piping by sequentially operating the third operating valve 136, the second operating valve 134, and the first operating valve 132 as necessary.

[ Cooling of Motor ]

Fig. 5 is a block diagram illustrating a state in which the compression part 10 is cooled using the refrigerant discharged from the condensation part 40 according to an embodiment of the present invention.

As shown in fig. 1 and 5, the first cooling pipe 116 is connected to the condensing part 40 and the first compressing part 20, and supplies a portion of the refrigerant condensed in the condensing part 40 to the first compressing part 20. One side of the first discharge pipe 118 is connected to the first compressing part 20 and the other side is connected to the fourth pipe 114 or the fourth separating part 88. Alternatively, the first cooling pipe 116 and the first discharge pipe 118 may be connected, thereby making it easier for the refrigerant to move.

The refrigerant, which cools the motor of the first compression part 20, may move to the fourth tube 114 along the first discharge tube 118 and then be supplied to the fourth separation part 88 together with the refrigerant passing through the third valve 96. Alternatively, the refrigerant that has cooled the motor of the first compression part 20 may move along the first discharge pipe 118 and directly move inside the fourth separation part 88.

The fourth separating portion 88 is connected to the fourth pipe 114, and the refrigerant passing through the third valve 96 is expanded and formed into a low pressure and low temperature state. Therefore, in the case where the first discharge pipe 118 is connected to the fourth separating part 88 or the fourth pipe 114, the refrigerant moving along the first discharge pipe 118 and the first cooling pipe 116 is also expanded, and the temperature thereof is lowered.

In the case where the first discharge pipe 118 is connected to the fourth separating part 88 or the fourth pipe 114, the motor provided in the first compressing part 20 is cooled by the refrigerant, and the surface temperature of the motor is about 15 to 20 ℃. Therefore, the motor provided in the first compression part 20 is cooled to a dew point temperature or higher, so that dew condensation can be prevented from occurring outside the motor, and a motor failure due to dew condensation can be prevented, thereby preventing an increase in maintenance costs.

If the first discharge pipe 118 is connected to another separation unit other than the fourth separation unit 88, the internal pressure of the first compression unit 20 increases. As the internal pressure of the first compression part 20 increases, the density of the fluid existing inside the first compression part 20 will increase. Therefore, a pressure loss of the first compression part 20 is generated due to an increase in Friction loss (Friction loss) inside the motor, and a problem of a decrease in efficiency of the motor occurs. In order to solve such a problem, the first discharge pipe 118 is connected to the fourth separating part 88, which has a relatively low pressure compared to other separating parts and can prevent the dew condensation problem, or to the fourth pipe 114 connected to the fourth separating part 88.

The second cooling pipe 117 is connected to the condensing part 40 and the second compressing part 30, and supplies a portion of the refrigerant condensed in the condensing part 40 to the second compressing part 30. The second discharge pipe 119 has one side connected to the second compressing part 30 and the other side connected to the fourth pipe 114 or the fourth separating part 88. Alternatively, the second cooling pipe 117 and the second discharge pipe 119 may be connected, thereby making it easier for the refrigerant to move.

The refrigerant, which cools the motor of the second compressing part 30, may move to the fourth tube 114 along the second discharge tube 119 and then be supplied to the fourth separating part 88 together with the refrigerant passing through the third valve 96. Alternatively, the refrigerant that has cooled the motor of the second compression part 30 may move along the second discharge pipe 119 and directly move inside the fourth separation part 88.

The fourth separating portion 88 is connected to the fourth pipe 114, and the refrigerant passing through the third valve 96 is expanded and formed into a low pressure and low temperature state. Therefore, in the case where the second discharge pipe 119 is connected to the fourth separating portion 88 or the fourth pipe 114, the refrigerant moving along the second discharge pipe 119 and the second cooling pipe 117 is also expanded, and the temperature thereof is lowered.

In the case where the second discharge pipe 119 is connected to the fourth separating part 88 or the fourth pipe 114, the motor provided in the second compressing part 30 is cooled by the refrigerant, and the surface temperature of the motor is about 15 to 20 ℃. Therefore, the motor provided in the second compression part 30 is cooled to a dew point temperature or higher, so that dew condensation can be prevented from occurring outside the motor, and a motor failure due to dew condensation can be prevented, thereby preventing an increase in maintenance costs.

If the second discharge pipe 119 is connected to a separate part other than the fourth separating part 88, the internal pressure of the second compressing part 30 is increased. As the internal pressure of the second compression part 30 increases, the density of the fluid existing inside the second compression part 30 will increase. Therefore, a pressure loss of the second compression part 30 is generated due to an increase in Friction loss (Friction loss) inside the motor, and a problem of a decrease in the efficiency of the motor occurs. In order to solve such a problem, the second discharge pipe 119 is connected to the fourth separating part 88 having a relatively low pressure compared to other separating parts and capable of preventing the dew condensation problem, or to the fourth pipe 114 connected to the fourth separating part 88.

[ movement of the gaseous refrigerant separated from the gas-liquid separation section ]

Fig. 4 is a block diagram illustrating a state in which the refrigerant in a gaseous state separated from the gas-liquid separation portion 80 according to an embodiment of the present invention moves toward the compression portion 10.

As shown in fig. 1 and 4, one side of the first supply pipe 120 is connected to the first separating part 82, and the other side is connected to the inlet of the fifth compressing end 36. Accordingly, after being separated into liquid refrigerant and gaseous refrigerant from the first separating part 82, the gaseous refrigerant moves to the inlet of the fifth compression end 36 along the first supply pipe 120 and is then compressed in the fifth compression end 36 together with the refrigerant compressed in the fourth compression end 34.

The second supply pipe 122 has one side connected to the second separating part 84 and the other side connected to an inlet of the fourth compressing end 34. Therefore, after being separated into liquid refrigerant and gaseous refrigerant from the second separating part 84, the gaseous refrigerant moves to the inlet of the fourth compression end 34 along the second supply pipe 122 and is then compressed in the fourth compression end 34 together with the refrigerant compressed in the third compression end 32.

The third supply pipe 124 is connected at one side to the third separation part 86 and at the other side to the inlet of the third compressing end 32. Therefore, after being separated into liquid refrigerant and gaseous refrigerant from the third separation part 86, the gaseous refrigerant moves to the inlet of the third compression end 32 along the third supply pipe 124, and is then compressed in the third compression end 32 together with the refrigerant compressed in the second compression end 24.

The fourth supply pipe 126 is connected at one side to the fourth separating portion 88 and at the other side to the inlet of the second compressing end 24. Therefore, after being separated into liquid refrigerant and gaseous refrigerant from the fourth separating part 88, the gaseous refrigerant moves to the inlet of the second compression end 24 along the fourth supply pipe 126, and is then compressed in the second compression end 24 together with the refrigerant compressed in the first compression end 22.

Fig. 6 is a perspective view showing a multistage compression type refrigeration apparatus 1 according to an embodiment of the present invention.

As shown in fig. 6, the accumulator 60 and the gas-liquid separating portion 80 are arranged in a straight direction and are located inside one housing-shaped reservoir. Therefore, as compared with the case where the accumulator 60 and the gas-liquid separation portion 80 are separately provided, the installation space can be significantly reduced, and the multistage compression refrigeration apparatus 1 can be installed in various spaces.

A tank-shaped evaporation unit 100 is provided on a side surface of the tank including the liquid reservoir 60 and the gas-liquid separation unit 80. A sump according to an embodiment of the present invention refers to a large tank for holding a fluid such as refrigerant, water, gas, oil, etc., and may have a housing formed in a cylindrical shape.

The compression section 10 is located on the upper side of a reservoir-shaped structure composed of an evaporator or accumulator 60 and a gas-liquid separation section 80. The compression part 10 includes a first compression part 20 and a second compression part 30, and the first compression part 20 and the second compression part 30 move a refrigerant through a pipe having a pipe shape.

[ actions of the invention ]

Hereinafter, the operation state of the multistage compression refrigeration apparatus 1 according to an embodiment of the present invention will be described in detail with reference to the drawings.

Fig. 7 is a P-H diagram of the multistage compression refrigeration apparatus 1 according to the embodiment of the present invention.

As shown in fig. 1 and 7, the refrigerant compressed in the first compression end 22 of the first compression part 20 moves to the second compression end 24 and is compressed. Then, the refrigerant compressed in the second compression end 24 moves to the third compression end 32 and is compressed. After that, the refrigerant compressed in the third compression end 32 moves to the fourth compression end 34 and is compressed. Then, the refrigerant compressed in the fourth compression end 34 moves to the fifth compression end 36 and is compressed. The refrigerant compressed in the compression portion 10 is in a saturated vapor state.

The gaseous refrigerant discharged from the second compressing part 30 moves to the condensing part 40 and exchanges heat with air or other refrigerant or fluid, thereby being formed into liquid refrigerant.

The refrigerant discharged from the condensing portion 40 moves to the accumulator 60 and is stored. Then, the refrigerant stored in the accumulator 60 passes through the first expansion valve portion 70, and moves to the inside of the first separation portion 82 in a state where its pressure is reduced and expansion is formed.

Is separated into gaseous refrigerant and liquid refrigerant in the first separating portion 82, and the gaseous refrigerant moves to the inlet of the fifth compression end 36 via the first supply pipe 120 and the first actuating valve 132. The gaseous refrigerant, which moves to the inlet of the fifth compression end 36, is compressed in the fifth compression end 36 together with the refrigerant discharged through the outlet of the fourth compression end 34.

The liquid refrigerant stored in the first separation portion 82 passes through the first valve 92 provided in the second expansion valve portion 90, and is expanded while its pressure is reduced. The refrigerant accumulated in the first separating portion 82 passes through the first valve 92 and moves to the inside of the second separating portion 84.

Is separated into gaseous refrigerant and liquid refrigerant in the second separating portion 84, and the gaseous refrigerant moves to the inlet of the fourth compression end 34 via the second supply pipe 122 and the second actuating valve 134. The gaseous refrigerant, which moves to the inlet of the fourth compression end 34, is compressed in the fourth compression end 34 together with the refrigerant discharged through the outlet of the third compression end 32.

The liquid refrigerant stored in the second separation portion 84 passes through the second valve 94 provided in the second expansion valve portion 90, and is expanded while its pressure is reduced. The refrigerant stored in the second separating portion 84 passes through the second valve 94 and moves to the inside of the third separating portion 86.

Is separated into gaseous refrigerant and liquid refrigerant in the third separation portion 86, and the gaseous refrigerant moves to the inlet of the third compression end 32 via the third supply pipe 124 and the third actuating valve 136. The gaseous refrigerant, which moves to the inlet of the third compression end 32, is compressed in the third compression end 32 together with the refrigerant discharged through the outlet of the second compression end 24.

The liquid refrigerant stored in the third separation portion 86 passes through the third valve 96 provided in the second expansion valve portion 90, and is expanded while its pressure is reduced. The refrigerant stored in the third separating portion 86 passes through the third valve 96 and moves to the inside of the fourth separating portion 88.

Is separated into gaseous refrigerant and liquid refrigerant in the fourth separating portion 88, and the gaseous refrigerant moves to the inlet of the second compression end 24 via the fourth supply pipe 126 and the fourth service valve 138. The gaseous refrigerant, which moves to the inlet of the second compression end 24, is compressed in the second compression end 24 together with the refrigerant discharged through the outlet of the first compression end 22.

The liquid refrigerant discharged from the fourth separating portion 88 passes through the fourth valve 98, and its pressure is reduced while expansion is formed, and its temperature is lowered. The refrigerant passing through the fourth valve 98 moves to the evaporation portion 100 along the fifth pipe 115 and exchanges heat with the fluid to be supplied to the demand, thereby being formed as gaseous refrigerant.

The refrigerant having passed through the evaporation unit 100 moves to the compression unit 10 again and is compressed.

As shown in fig. 5, the refrigerant passing through the condensing portion 40 is a liquid refrigerant, and a portion of the refrigerant is supplied to the first and

second compressing portions

20 and 30.

A part of the refrigerant discharged from the condensing portion 40 moves along the first cooling pipe 116, and is expanded while its temperature is lowered. This refrigerant moves to the first compression part 20 and cools the first compression part 20, and then moves to the fourth tubes 114 via the first discharge tube 118. In addition, a portion of the refrigerant discharged from the condensation part 40 moves to the second compression part 30 along the second cooling pipe 117 and cools the second compression part 30, and then moves to the fourth pipe 114 via the second discharge pipe 119.

The refrigerant moved to the fourth pipe 114 is moved to the fourth separating portion 88 together with the refrigerant passed through the third valve 96, and is separated into the gaseous refrigerant and the liquid refrigerant.

In the P-H diagram shown in fig. 7, the horizontal axis represents enthalpy (H) and the vertical axis represents pressure (P). And, C denotes a total cooling capacity.

Fig. 8 is a P-H diagram of the fourth separator 88 according to an embodiment of the present invention in a non-operating state.

As shown in fig. 1 and 8, during the partial load operation of the multistage compression refrigeration apparatus 1, the control unit 140 stops the operation of the fourth separation unit 88 having the lowest pressure among the four separation units provided in the gas-liquid separation unit 80, thereby reducing the refrigeration capacity of the multistage compression refrigeration apparatus 1.

To stop the operation of the fourth separator 88, the controller 140 sends a control signal to the fourth operating valve 138, so that the fourth operating valve 138 operates in the closed mode to close the fourth supply pipe 126. Therefore, the movement of the gaseous refrigerant separated from the fourth separating portion 88 to between the first and second compression ends 22 and 24 through the fourth supply pipe 126 will be stopped.

Since the movement of the gaseous refrigerant in the fourth supply pipe 126 is blocked, the third separating portion 86 will function as the existing fourth separating portion 88. In addition, in the multistage compression refrigeration apparatus 1, since the fourth separation portion 88 does not operate, the partial load operation in which the cooling capacity is reduced can be performed.

When the fourth separating unit 88 is not operated, the refrigeration capacity is decreased by the first refrigeration capacity reduction amount R1, and the multistage compression refrigeration apparatus 1 is operated at the first refrigeration capacity C1 obtained by subtracting the first refrigeration capacity reduction amount R1 from the total refrigeration capacity C.

As shown in fig. 1 and 9, when the multistage compression refrigeration apparatus 1 is in the partial load operation, the control unit 140 sequentially stops the operations of the fourth separation section 88 (which has the lowest pressure among the four separation sections provided in the gas-liquid separation section 80) and the third separation section 86 (which has the lowest pressure among the separation sections other than the fourth separation section 88), thereby reducing the refrigeration capacity of the multistage compression refrigeration apparatus 1.

To stop the operation of the fourth separator 88, the controller 140 sends a control signal to the fourth operating valve 138, and causes the fourth operating valve 138 to operate in the closed mode, thereby closing the fourth supply pipe 126. Therefore, the movement of the gaseous refrigerant separated from the fourth separating portion 88 to between the first and second compression ends 22 and 24 through the fourth supply pipe 126 will be stopped.

To stop the operation of the third separator 86, the controller 140 sends a control signal to the third operating valve 136, so that the third operating valve 136 operates in the closed mode to close the third supply pipe 124. Therefore, the movement of the gaseous refrigerant separated from the third separation part 86 to between the second compression end 24 and the third compression end 32 via the third supply pipe 124 will be stopped.

Since the movement of the gaseous refrigerant in the fourth and

third supply pipes

126 and 124 is blocked, the second separating portion 84 will function as the existing fourth and

third separating portions

88 and 86. In addition, in the multistage compression refrigeration apparatus 1, the partial load operation in which the fourth separation unit 88 and the third separation unit 86 are not operated and the refrigeration capacity is reduced for the second time can be performed.

When the third separating unit 86 and the fourth separating unit 88 are not operated, the refrigeration capacity is decreased by the second reduced refrigeration capacity R2, and the multistage compression refrigeration apparatus 1 is operated at the second refrigeration capacity C2 obtained by subtracting the second reduced refrigeration capacity R2 from the total refrigeration capacity C.

As shown in fig. 1 and 10, when the multistage compression refrigeration apparatus 1 performs the partial load operation, the control unit 140 sequentially stops: a fourth separation section 88 having the lowest pressure among the four separation sections of the gas-liquid separation section 80; the third separating portion 86 having the lowest pressure among the other separating portions except the fourth separating portion 88; the operation of the second separating unit 84 having the lowest pressure among the separating units other than the fourth separating unit 88 and the third separating unit 86 reduces the cooling capacity of the multistage compression refrigeration apparatus 1.

In order to stop the operation of the second separator 84, the controller 140 sends a control signal to the second operation valve 134, thereby operating the second operation valve 134 in the closed mode to close the second supply pipe 122. Therefore, the movement of the gaseous refrigerant separated from the second separating part 84 to between the third compression end 32 and the fourth compression end 34 via the second supply pipe 122 will be stopped.

Since the movement of the gaseous refrigerant on the fourth supply pipe 126, the third supply pipe 124 and the second supply pipe 122 is blocked, the first separating part 82 will function as the existing fourth separating part 88, the third separating part 86 and the second separating part 84. In the multistage compression refrigeration apparatus 1, the second separation unit 84, the third separation unit 86, and the fourth separation unit 88 may be operated for the partial load operation in which the cooling capacity is reduced for the third time.

When the second separating unit 84, the third separating unit 86, and the fourth separating unit 88 are not operated, the refrigeration capacity is decreased by the third reduced refrigeration capacity R3, and the multistage compression refrigeration apparatus 1 is operated at the third refrigeration capacity C3 obtained by subtracting the third reduced refrigeration capacity R3 from the total refrigeration capacity C.

Fig. 11 is a P-H diagram when all of the gas-liquid separation sections 80 do not operate according to the embodiment of the present invention.

As shown in fig. 1 and 11, when the multistage compression refrigeration apparatus 1 is in the partial load operation, the control unit 140 sequentially stops the operations of the fourth separation unit 88 having the lowest pressure to the first separation unit 82 having the highest pressure among the four separation units of the gas-liquid separation unit 80, thereby reducing the refrigeration capacity of the multistage compression refrigeration apparatus 1.

First, to stop the operation of the fourth separator 88, the controller 140 sends a control signal to the fourth operating valve 138, and causes the fourth operating valve 138 to operate in the closed mode, thereby closing the fourth supply pipe 126. Therefore, the movement of the gaseous refrigerant separated from the fourth separating portion 88 to between the first and second compression ends 22 and 24 through the fourth supply pipe 126 will be stopped.

Then, in order to stop the operation of the third separator 86, the controller 140 sends a control signal to the third operating valve 136, so that the third operating valve 136 operates in the closed mode to close the third supply pipe 124. Therefore, the movement of the gaseous refrigerant separated from the third separation part 86 to between the second compression end 24 and the third compression end 32 via the third supply pipe 124 will be stopped.

Thereafter, the control unit 140 generates a control signal to the second operating valve 134 in order to stop the operation of the second separator 84, thereby operating the second operating valve 134 in the closed mode to close the second supply pipe 122. Therefore, the movement of the gaseous refrigerant separated from the second separating part 84 to between the third compression end 32 and the fourth compression end 34 via the second supply pipe 122 will be stopped.

Then, in order to stop the operation of the first separating portion 82, the control portion 140 transmits a control signal to the first operating valve 132, thereby operating the first operating valve 132 in the closed mode to close the first supply pipe 120. Therefore, the movement of the gaseous refrigerant separated from the first separating part 82 to between the fourth compression end 34 and the fifth compression end 36 via the first supply pipe 120 will be stopped.

Since the movement of the gaseous refrigerant on the fourth supply pipe 126, the third supply pipe 124, the second supply pipe 122, and the first supply pipe 120 is blocked, the gas-liquid separation portion 80 does not operate. Further, since the refrigerant discharged from the condensing unit 40 directly moves to the evaporating unit 100, the multistage compression refrigeration apparatus 1 can perform the partial load operation in which the fourth separating unit 88, the third separating unit 86, the second separating unit 84, and the first separating unit 82 do not operate and the cooling capacity is reduced for the fourth time.

When the fourth separating unit 88, the third separating unit 86, the second separating unit 84, and the first separating unit 82 are not operated, the refrigeration capacity decreases by the fourth reduced refrigeration capacity R4, and the multistage compression refrigeration apparatus 1 operates at the fourth refrigeration capacity C4 obtained by subtracting the fourth reduced refrigeration capacity R4 from the total refrigeration capacity C.

Therefore, the P-H diagram shown in fig. 11 has the same shape as the P-H diagram of the refrigeration apparatus using the single-stage compressor.

In the normal operation of the multistage compression refrigeration apparatus 1 according to the embodiment of the present invention, the cooling capacity is set to the total cooling capacity C. The cooling capacity decreased during the partial load operation in which the cooling capacity is decreased for the first time is set to the first decreased cooling capacity R1. The cooling capacity decreased during the partial load operation in which the cooling capacity is decreased for the second time is set to the second decreased cooling capacity R2. Further, the cooling capacity decreased during the partial load operation in which the cooling capacity is decreased for the third time is set to the third decreased cooling capacity R3. Further, the cooling capacity decreased during the partial load operation in which the cooling capacity is decreased fourth is set to a fourth decreased cooling capacity R4.

In this case, the value of the refrigeration capacity decreased during the part load operation has a relationship of R1< R2< R3< R4.

The control portion 140 closes the conduit portion 110 through which the gaseous refrigerant moves in the order of the fourth separating portion 88, the third separating portion 86, the second separating portion 84, and the first separating portion 82, so that the low load capacity of the multistage compression refrigeration apparatus 1 can be easily controlled.

In the present invention, the multi-stage gas-liquid separation unit 80 of the large capacity air-cooled refrigerator using the multi-stage compressor can realize the partial load operation. Further, in the conventional technique, since the refrigerant is directly moved from the condenser to the evaporator by using the high-temperature gas bypass, there is a problem that a large noise is generated because the flow velocity in the pipe is high. However, in the present invention, the condensed refrigerant is expanded in sequence while passing through the plurality of separation portions, and therefore, the effect of reducing noise is exhibited even when the multistage compression refrigeration apparatus 1 is operated under partial load.

In the refrigeration apparatus according to the related art, the gas-liquid separation portion 80 functions only to separate the condensed refrigerant into a liquid state and a gaseous state, but in the present invention, the pipeline portion 110 for connecting the gas-liquid separation portion 80 and the compression portion 10 may be sequentially closed, and only a part of the expansion line may be operated, thereby sequentially reducing the refrigeration capacity.

[ Explanation of Effect ]

The control portion 140 controls the control valve portion 130, the control valve portion 130 being provided at the pipe portion 110 that supplies the gaseous refrigerant to the compression portion 10 having a plurality of compression ends, so the cooling capacity of the cooling device can be easily controlled, and the reduction in cooling efficiency can be minimized. In addition, the gas-liquid separation portion 80 sequentially blocks the piping portion 110 that transports the gaseous refrigerant from the separation portion having a lower pressure toward the separation portion having a higher pressure, and thus can respond in stages to the partial load of the refrigeration capacity. Further, the refrigerant moving from the condensing portion 40 toward the evaporating portion 100 passes through the separating portions of the plurality of gas-liquid separating portions 80 and expands sequentially, so that noise during the partial load operation can be reduced.

In addition, since the gas-liquid separation portion 80 is provided downstream of the accumulator 60 and the gas-liquid separation portion 80 and the accumulator 60 are provided in one housing in an integrated manner, the space for providing the gas-liquid separation portion 80 can be minimized and the space utilization rate can be improved.

In addition, although the entire size of the refrigeration apparatus and the complexity of the pipe structure increase when the conventional external sump-shaped gas-liquid separation apparatus is applied, the gas-liquid separation portion 80 and the reservoir 60 are formed integrally to form a condenser provided in the conventional refrigerator, so that the spatial limitation can be solved.

Further, since the plurality of separation portions provided in the gas-liquid separation portion 80 are provided in series in order and adjacent to the liquid reservoir 60, the length of the pipe for transporting the refrigerant can be minimized, and the installation cost and the maintenance cost can be reduced. That is, the gas-liquid separation device provided in the related art refrigeration apparatus is disposed in parallel beside the compressor, and it is necessary to perform an installation work of pipes for conveying the liquid refrigerant and the gaseous refrigerant to the evaporator and the compressor, respectively. However, in the present invention, the structure of the delivery piping of the liquid refrigerant is simple, and the installation length of the piping is reduced as compared with the related art, so that the installation space of the pipe part 110 can be reduced. Further, since the reservoir 60 and the gas-liquid separating portion 80 are integrally formed, the installation of the pipe portion 110 around the compression portion 10 is simplified, and maintenance work can be easily performed.

In addition, the gas-liquid separation portion 80 is continuously provided in plurality in proportion to the number of compression ends provided to the compression portion 10, and after separating the refrigerant into gas and liquid refrigerants, the gaseous refrigerant is delivered to the compression portion 10, so that the refrigeration efficiency can be improved.

In addition, the present invention can control the cooling capacity using four separate parts applied to the five-stage refrigeration cycle. In addition, the present invention can respond to a low load by adjusting the number of the separation portions that operate to reduce the decrease in cooling efficiency.

As described above, the present invention is described with reference to the illustrated drawings, but the present invention is not limited to the embodiments and drawings disclosed in the present specification, and it is apparent to those skilled in the art that various modifications can be made within the scope of the technical idea of the present invention. In addition, even if the operation and effect of the configuration of the present invention are not explicitly described or recited while describing the embodiment of the present invention, it should be recognized that the effect can be predicted from the configuration.

Claims

1. A multistage compression type refrigerating apparatus comprising:

a compression unit configured to compress a refrigerant at a plurality of compression ends;

a condensing part connected to the compressing part and condensing the refrigerant passing through the compressing part by heat exchange;

a first expansion valve portion that is provided in a pipe that guides movement of the refrigerant discharged from the condensation portion, and that expands the refrigerant;

a gas-liquid separation portion that is provided with a plurality of separation portions, and that receives the refrigerant passing through the first expansion valve portion and separates into liquid refrigerant and gaseous refrigerant, and supplies gaseous refrigerant to the compression portion;

a second expansion valve section that is provided in a pipe connected to the gas-liquid separation section and expands the refrigerant discharged from the gas-liquid separation section;

a control valve portion that is provided in a plurality of pipes that guide the gaseous refrigerant separated from the gas-liquid separation portion to the compression portion, and that controls movement of the refrigerant; and

and a control unit for controlling the operation of the control valve unit.

2. The multi-stage compression refrigeration unit of claim 1,

the compression section includes:

a first compression unit that compresses the refrigerant sent through the evaporation unit at a plurality of compression ports; and

and a second compression part connected to the first compression part and compressing the refrigerant passing through the first compression part and compressed at a plurality of compression ends.

3. The multi-stage compression refrigeration unit of claim 2,

the first compression part includes:

a first compression end for compressing the refrigerant sent through the evaporation part; and

a second compression end disposed downstream of the first compression end and re-compressing the refrigerant compressed in the first compression end.

4. The multi-stage compression refrigeration unit of claim 3,

the second compression part includes:

a third compression end compressing the refrigerant delivered through the second compression end;

a fourth compression end disposed downstream of the third compression end and compressing the refrigerant compressed in the third compression end again; and

a fifth compression end disposed downstream of the fourth compression end and compressing the refrigerant compressed in the fourth compression end again.

5. The multi-stage compression refrigeration unit of claim 4,

the gas-liquid separation section includes:

a first separation section connected to the first expansion valve section;

a second separation portion that is provided downstream of the first separation portion and separates the refrigerant sent from the first separation portion into a gaseous refrigerant and a liquid refrigerant;

a third separation portion that is provided downstream of the second separation portion and separates the refrigerant sent from the second separation portion into a gaseous refrigerant and a liquid refrigerant; and

a fourth separation portion that is provided downstream of the third separation portion and separates the refrigerant sent from the third separation portion into a gaseous refrigerant and a liquid refrigerant.

6. The multi-stage compression refrigeration unit of claim 5,

the control valve part includes a first operation valve provided in a first supply pipe that guides the gaseous refrigerant separated from the first separation part to an inlet of the fifth compression port and operates to open and close a pipe in accordance with a control signal of the control part.

7. The multi-stage compression refrigeration unit of claim 6,

the control valve part further includes a second operation valve provided in a second supply pipe that guides the gaseous refrigerant separated from the second separation part to an inlet of the fourth compression port and operates to open and close a pipe according to a control signal of the control part.

8. The multi-stage compression refrigeration unit of claim 7,

the control valve part further includes a third operation valve provided to a third supply pipe guiding the gaseous refrigerant separated from the third separation part to an inlet of the third compression port and operated to open and close a pipe according to a control signal of the control part.

9. The multi-stage compression refrigeration unit of claim 8,

the control valve part further includes a fourth operation valve provided in a fourth supply pipe that guides the gaseous refrigerant separated from the fourth separation part to the inlet of the second compression port and operates to open and close the pipe in accordance with a control signal of the control part.

10. The multi-stage compression refrigeration unit of claim 5,

the second inflation valve portion includes:

a first valve connected to a second pipe for connecting the first separation part and the second separation part;

a second valve connected to a third pipe for connecting the second separation part and the third separation part;

a third valve connected to a fourth pipe for connecting the third separation part and the fourth separation part; and

and a fourth valve connected to a fifth pipe for connecting the fourth separation part and the evaporation part.