Evaporator

Abstract

The purpose of the present invention is to improve performance by improving heat exchange efficiency in a heat transfer tube group. An evaporator is provided with: a heat transfer tube group having a plurality of heat transfer tubes through which a heat exchange medium flows; a connection part (51) into which the refrigerant expanded by the expansion part is introduced, said refrigerant being a refrigerant in a gas-liquid two-phase state in which a liquid refrigerant and bubbles are mixed; a mixing unit (53) to which the refrigerant introduced through the connection unit (51) is supplied and which mixes the supplied refrigerant; and a header (54) for supplying the refrigerant mixed by the mixing unit (53) to the heat transfer tube group.

Description

Technical Field

[0001] This invention relates to an evaporator. Background Technology

[0002] As an evaporator used in refrigeration machines, a liquid film evaporator is known, which supplies liquid refrigerant from above to a heat transfer tube assembly through which the medium to be cooled flows. In this type of liquid film evaporator, refrigerant expanded by an expansion valve is introduced via piping (e.g., Patent Document 1).

[0003] Patent document 1 discloses an evaporator in which refrigerant received from a condenser is supplied to a bundle of hoses from multiple locations via a distributor.

[0004] Previous technical documents

[0005] Patent documents

[0006] Patent Document 1: U.S. Patent Application Publication No. 2006 / 0080998 Summary of the Invention

[0007] The technical problem to be solved by the invention

[0008] The refrigerant flowing toward the evaporator experiences gas entrainment or flash evaporation due to pressure drop during its flow. Therefore, the refrigerant flowing toward the evaporator is in a two-phase state, containing gas-liquid bubbles in the liquid refrigerant (hereinafter referred to as "refrigerant liquid").

[0009] Furthermore, the refrigerant in a gas-liquid two-phase state flowing towards the evaporator experiences deviations in the refrigerant liquid across the flow path cross-section due to bends in the piping or uneven cross-sections. Specifically, for example, in bends in the piping, the refrigerant liquid tends to be biased towards the outer periphery due to the density difference between the bubbles and the refrigerant liquid, while the bubbles tend to be biased towards the inner periphery. This can potentially reduce the uniformity of the refrigerant liquid and bubbles across the flow path cross-section.

[0010] The refrigerant introduced into the evaporator is supplied to the heat transfer tube assembly. However, if the refrigerant, in a two-phase state, is supplied to the heat transfer tube assembly with reduced uniformity, the amount of refrigerant supplied will deviate depending on the location. As a result, the heat exchange efficiency in the heat transfer tube assembly decreases, and the performance of the evaporator may be reduced.

[0011] The present invention was made in view of this situation, and its object is to provide an evaporator that can improve the performance by increasing the heat exchange efficiency in the heat transfer tube assembly.

[0012] means for solving technical problems

[0013] To address the aforementioned issues, the evaporator of the present invention employs the following solution.

[0014] An evaporator according to one aspect of the present invention comprises: a heat transfer tube assembly having a plurality of heat transfer tubes through which a heat exchange medium flows; an inlet for introducing a refrigerant in a gas-liquid two-phase state; a mixing section for being supplied with the refrigerant introduced through the inlet and mixing the supplied refrigerant; and a supply section for supplying the refrigerant mixed by the mixing section to the heat transfer tube assembly.

[0015] Invention Effects

[0016] According to the present invention, the heat exchange efficiency in the heat transfer tube assembly can be improved, thereby improving the performance of the evaporator. Attached Figure Description

[0017] Figure 1 This is a perspective view showing the evaporator according to the first embodiment of the present invention.

[0018] Figure 2 This is a perspective view of the evaporator according to the first embodiment of the present invention, showing the state after the shell and cover have been removed.

[0019] Figure 3 This is a schematic longitudinal sectional view showing the main parts of the evaporator according to the first embodiment of the present invention.

[0020] Figure 4 This is a perspective view showing the mixing section of the evaporator provided in the first embodiment of the present invention.

[0021] Figure 5 This is a schematic longitudinal sectional view showing the main parts of the evaporator according to a modified example of the first embodiment of the present invention.

[0022] Figure 6 This is a perspective view showing the mixing section of the evaporator provided in a modified example of the first embodiment of the present invention.

[0023] Figure 7 This is a schematic longitudinal sectional view showing the main parts of the evaporator according to the second embodiment of the present invention. Detailed Implementation

[0024] The following uses Figures 1 to 7 An embodiment of the evaporator according to the present invention will be described. Furthermore, in the following description and accompanying drawings, the vertical direction is defined as the Z-axis direction, the direction in which the heat transfer tube extends is defined as the X-axis direction, and the direction orthogonal to both the Z-axis and X-axis directions is defined as the Y-axis direction.

[0025] [First Implementation]

[0026] The evaporator 1 described in this embodiment is applicable to a turbo refrigeration system. The turbo refrigeration system includes a turbo compressor (not shown) that compresses the refrigerant, a condenser (not shown) that condenses the refrigerant compressed by the turbo compressor, an expansion valve (not shown) that expands the refrigerant condensed by the condenser, and an evaporator that evaporates the refrigerant expanded by the expansion valve, and is configured as a unit. Each component is connected by piping for refrigerant flow. For example, low-pressure refrigerants such as R1233zd, which operate at a maximum pressure of less than 0.2 MPaG, are used as refrigerants. However, the applicable refrigerant is not limited to low-pressure refrigerants. For example, high-pressure refrigerants can be used.

[0027] Evaporator 1 is supplied with refrigerant in a two-phase gas-liquid state, expanded by the expansion valve. For example... Figure 1 and Figure 2 As shown, the evaporator 1 includes a pressure vessel 10 forming the outer shell, a refrigerant inlet pipe (inlet section) 20 for introducing refrigerant in a gas-liquid two-phase state expanded by an expansion valve into the interior of the pressure vessel 10, a heat transfer tube assembly 30 housed inside the pressure vessel 10, a cover 40 covering the heat transfer tube assembly 30 from above, and a supply device 50 disposed above the heat transfer tube assembly 30 for supplying refrigerant introduced through the refrigerant inlet pipe 20 to the heat transfer tube assembly 30. Additionally, in Figure 2 Due to the nature of the illustrations, the pressure vessel 10 and the enclosure 40 are omitted from the diagram. Furthermore, in... Figure 1 In the diagram, the pressure vessel 10 is made transparent.

[0028] like Figure 1 As shown, the pressure vessel 10 integrally comprises a cylindrical portion 11 with its central axis extending along the X-axis direction and two tube sheets (not shown) closing both ends along the central axis direction (X-axis direction) of the cylindrical portion 11. The cylindrical portion 11 is arranged in a manner where its central axis is approximately horizontal. Each tube sheet is a disc-shaped plate. Liquid refrigerant is stored in the lower part of the pressure vessel 10. An outlet opening 12 communicating between the internal and external spaces of the pressure vessel 10 is provided at the upper end of the cylindrical portion 11. The outlet opening 12 is located at one end in the X-axis direction. An inlet opening 13 communicating between the internal and external spaces of the pressure vessel 10 is provided on the side of the cylindrical portion 11. A refrigerant inlet pipe 20 is inserted through the inlet opening 13.

[0029] Furthermore, in the following description, when referred to simply as "inner side" and "outer side", they refer to the "inner side" and "outer side" with the central axis of the cylindrical portion 11 as the reference. That is, "inner side" refers to the side with the central axis of the cylindrical portion 11, and "outer side" refers to the side with the inner circumferential surface of the cylindrical portion 11.

[0030] In the refrigerant inlet pipe 20, a gas-liquid two-phase refrigerant flows internally. The refrigerant inlet pipe 20 includes a first horizontal pipe 21 extending along the Y-axis direction, a second horizontal pipe 22 that bends approximately at a right angle from the downstream end of the first horizontal pipe 21 and extends along the X-axis direction, a vertical pipe 23 that bends approximately at a right angle from the downstream end of the second horizontal pipe 22 and extends upward, and a third horizontal pipe 24 that bends approximately at a right angle from the downstream end (upper end) of the vertical pipe 23 and extends along the X-axis direction.

[0031] The first horizontal pipe 21, the second horizontal pipe 22, and the vertical pipe 23 are disposed on the outside of the pressure vessel 10. Furthermore, the third horizontal pipe 24 penetrates the inlet opening 13. That is, a portion of the third horizontal pipe 24 is disposed on the outside of the pressure vessel 10, and a portion of the third horizontal pipe 24 is disposed inside the pressure vessel 10.

[0032] Furthermore, the refrigerant inlet pipe 20 includes a fourth horizontal pipe 25 disposed above the heat transfer pipe assembly 30 and extending in a straight line along the X-axis direction, a fifth horizontal pipe 26 disposed at both ends of the fourth horizontal pipe 25 in the X-axis direction and extending in a straight line along the Y-axis direction, and a supply pipe 27 that bends downward at approximately a right angle from both ends of the pair of fifth horizontal pipes 26 in the Y-axis direction.

[0033] The fourth horizontal pipe 25, the fifth horizontal pipe 26, and the supply pipe 27 are housed inside the pressure vessel 10. The fourth horizontal pipe 25, the fifth horizontal pipe 26, and the supply pipe 27 are located in the upper part of the pressure vessel 10. The fourth horizontal pipe 25, the fifth horizontal pipe 26, and the supply pipe 27 are located above the cover 40.

[0034] The fourth horizontal pipe 25 is located approximately at the center of the pressure vessel 10 in the X-axis direction. The downstream end of the third horizontal pipe 24 is connected to the side of the fourth horizontal pipe 25 approximately at its center in the X-axis direction. The downstream end (one or the other end in the X-axis direction) of the third horizontal pipe 24 is connected to the side of each fifth horizontal pipe 26 approximately at its center in the Y-axis direction. The downstream end (lower end) of the supply pipe 27 is connected to the supply device 50. The supply pipe 27 penetrates the enclosure 40.

[0035] Thus, the refrigerant inlet pipe 20 has multiple bends (e.g., the connection between the first horizontal pipe 21 and the second horizontal pipe 22, or the connection between the fifth horizontal pipe 26 and the supply pipe 27, etc.).

[0036] like Figure 1 and Figure 2 As shown, the heat transfer tube assembly 30 includes a flooded heat transfer tube assembly 31, a lower liquid film heat transfer tube assembly 32, and an upper liquid film heat transfer tube assembly 33. Additionally, in Figure 1 and Figure 2 Due to the nature of the illustration, the heat transfer tubes included in each heat transfer tube group are not shown separately.

[0037] The flooded heat transfer tube assembly 31 is housed within the pressure vessel 10. Furthermore, the flooded heat transfer tube assembly 31 is immersed in liquid refrigerant stored in the lower part of the pressure vessel 10. That is, it is positioned below the liquid level of the stored refrigerant.

[0038] The lower liquid film heat transfer tube assembly 32 is housed within the pressure vessel 10. The lower liquid film heat transfer tube assembly 32 is positioned higher than the flooded heat transfer tube assembly 31. The lower liquid film heat transfer tube assembly 32 is positioned higher than the liquid level of the stored refrigerant.

[0039] The upper liquid film heat transfer tube assembly 33 is housed in the pressure vessel 10. The upper liquid film heat transfer tube assembly 33 is positioned higher than the lower liquid film heat transfer tube assembly 32. The upper liquid film heat transfer tube assembly 33 is positioned higher than the liquid level of the stored refrigerant.

[0040] The lower liquid film heat transfer tube assembly 32 and the upper liquid film heat transfer tube assembly 33 are separated in the vertical direction.

[0041] The flooded heat transfer tube assembly 31, the lower liquid film heat transfer tube assembly 32, and the upper liquid film heat transfer tube assembly 33 each have multiple heat transfer tubes extending along the X-axis direction. These multiple heat transfer tubes are arranged substantially parallel to each other. The multiple heat transfer tubes are arranged at predetermined intervals in the vertical and Y-axis directions. Specifically, the multiple heat transfer tubes are arranged in multiple segments in the vertical direction and in multiple columns in the Y-axis direction. Water (hereinafter referred to as "cooled water"), serving as the heat exchange medium, flows inside each heat transfer tube. Furthermore, each heat transfer tube is formed in a straight line. Each heat transfer tube extends from one end of the pressure vessel 10 in the X-axis direction to the other end and penetrates each tube sheet (not shown). The length of the flooded heat transfer tube assembly 31, the lower liquid film heat transfer tube assembly 32, and the upper liquid film heat transfer tube assembly 33 in the X-axis direction is greater than that of the manifold (supply section) 54 described later (see reference). Figure 2 The length of the X-axis is longer.

[0042] The cover 40 is configured such that its plate surface is horizontal. The cover 40 is positioned above the manifold 54 of the supply device 50. Multiple supply pipes 27 extend through the cover 40. Furthermore, the cover 40 extends along the upper liquid film heat transfer tube assembly 33 over approximately the entire area of ​​the pressure vessel 10 in the X-axis direction. Alternatively, the cover 40 may be provided only in a portion of the X-axis direction.

[0043] like Figure 2 and Figure 3 As shown, the supply device 50 is located at the lower end of each supply pipe 27. The structures of each supply device 50 are generally the same, so the following description will focus on one supply device 50 and omit the description of the other supply devices 50.

[0044] The supply device 50 includes a connecting part (inlet part) 51 connected to the lower end of the supply pipe 27, a rectangular part 52 connected to the lower end of the connecting part 51 and rectangular in shape when viewed from above, a mixing part 53 disposed below the rectangular part 52, and a pair of manifolds 54 connected to the two ends of the rectangular part 52 in the Y-axis direction.

[0045] like Figure 3 As shown, the connecting portion 51 is a cylindrical component that extends linearly in the vertical direction. The upper end of the connecting portion 51 is connected to the lower end of the supply pipe 27. The lower end of the connecting portion 51 is connected to the center of the upper surface of the rectangular portion 52 in both the X-axis and Y-axis directions. A circular outlet 51a with an opening into the space formed inside the rectangular portion 52 is formed at the lower end of the connecting portion 51. The diameter D2 of the outlet 51a is shorter than the diameter D1 of the inlet 53a of the mixing portion 53. Furthermore, the opening area of ​​the outlet 51a is smaller than the opening area of ​​the inlet 53a of the mixing portion 53.

[0046] The rectangular portion 52 is a component that appears roughly square when viewed from above. The rectangular portion 52 is also roughly cuboid in shape. A space is formed inside the rectangular portion 52. The lower end of the connecting portion 51 is connected to the upper surface of the rectangular portion 52. Furthermore, the upper end of the mixing portion 53 is connected to the lower surface of the rectangular portion 52.

[0047] At both ends of the rectangular portion 52 in the Y-axis direction, flow path portions 52a are provided to guide the refrigerant mixed by the mixing portion 53 to the manifold 54. The flow path portions 52a extend along the Y-axis direction from the outlet 51a of the connecting portion 51 and the inlet 53a of the mixing portion 53. The manifold 54 is connected to the end of the flow path portion 52a in the Y-axis direction. A small-diameter portion 52b with a smaller flow path area than the flow path portion 52a is provided at the connection between the flow path portion 52a and the manifold 54.

[0048] Furthermore, the shape of the rectangular portion 52 is not limited to the shape described above. For example, it can be circular when viewed from above, or it can be irregular in shape when viewed from above.

[0049] like Figure 4 As shown, the mixing section 53 is a hemispherical component configured to protrude downwards. The mixing section 53 has an internal space. The mixing section 53 is configured such that its horizontal cross-section decreases as it moves downwards. The bottom surface 53b of the mixing section 53 is a curved surface.

[0050] The upper end of the mixing section 53 is connected to the center of the lower surface of the rectangular section 52 in both the X-axis and Y-axis directions. A circular inlet 53a, opening into the space formed inside the rectangular section 52, is formed at the upper end of the mixing section 53. The diameter D1 of the inlet 53a is longer than the diameter D2 of the outlet 51a of the connecting section 51. Furthermore, the opening area of ​​the inlet 53a is larger than the opening area of ​​the outlet 51a of the connecting section 51.

[0051] The connection between the mixing section 53 and the rectangular section 52 is at the same height throughout the entire circumferential region. That is, the inlet 53a is formed along the horizontal plane. By forming the inlet 53a in this way, mixing can be performed more appropriately.

[0052] The outlet 51a of the connecting part 51 and the inlet 53a of the mixing part 53 are configured such that the entire area of ​​the outlet 51a overlaps with the inlet 53a when viewed from above. Furthermore, the outlet 51a of the connecting part 51 and the inlet 53a of the mixing part 53 are separated in the vertical direction due to the presence of the rectangular part 52.

[0053] like Figure 2 As shown, manifold 54 is a tubular component extending along the X-axis. Viewed from the side, manifold 54 is approximately rectangular. Furthermore, as... Figure 3 As shown, when viewed from the side, the manifold 54 is curved downwards at its lower end. Multiple ejector sections (not shown) are formed at the lower end of the manifold 54. Each ejector section can be formed as a slit along its length in the Y-axis direction. The multiple ejector sections are arranged at equal intervals in the X-axis direction. Refrigerant flowing within the manifold 54 is ejected from each ejector section. The manifold 54 supplies the refrigerant ejected from each ejector section from above to the heat transfer tube assembly 30.

[0054] Next, the flow of refrigerant in the evaporator 1 according to this embodiment will be described.

[0055] The refrigerant expanded by the expansion valve (gas-liquid two-phase flow) flows through the refrigerant inlet pipe 20 and is guided into the interior of the pressure vessel 10. The refrigerant flowing into the pressure vessel 10 flows through the refrigerant inlet pipe 20 and is introduced into the supply device 50. The refrigerant flowing through the refrigerant inlet pipe 20 is in a gas-liquid two-phase state containing gas bubbles in the liquid refrigerant (hereinafter referred to as "refrigerant liquid").

[0056] The gas-liquid two-phase flow circulating in the refrigerant inlet pipe 20 passes through bends or sections with uneven cross-sections in the flow path, causing a shift in the refrigerant liquid's air bubbles across the flow path cross-section. Specifically, for example, in bends, the refrigerant liquid tends to be biased towards the outer periphery, while the air bubbles tend to be biased towards the inner periphery. Thus, the refrigerant is introduced into the supply device 50 in a state where the uniformity of the refrigerant liquid and air bubbles across the flow path cross-section is reduced.

[0057] like Figure 3 As shown, the refrigerant introduced into the supply device 50 is introduced into the mixing section 53 via the connecting portion 51 and the rectangular portion 52. At this time, the refrigerant flows from top to bottom (refer to arrow A1), and the mixing section 53 receives the refrigerant using its bottom surface 53b. The gas-liquid two-phase flow of refrigerant introduced into the mixing section 53 mixes with refrigerant liquid and air bubbles in the mixing section 53. The mixed refrigerant overflows from the mixing section 53 and flows into the flow path portion 52a (refer to arrow A2). The refrigerant flowing into the flow path portion 52a flows within the flow path portion 52a and is introduced into the manifold 54 via the small-diameter portion 52b.

[0058] like Figure 2 As shown, liquid refrigerant flowing within manifold 54 is sprayed downwards through multiple nozzles (not shown) formed at the lower end of manifold 54. The liquid refrigerant sprayed from manifold 54 contacts the uppermost heat transfer tube of the liquid film heat transfer tube assembly (upper liquid film heat transfer tube assembly 33 and lower liquid film heat transfer tube assembly 32), covering the outer circumferential surface of the heat transfer tube in a film-like manner. The refrigerant covering the outer circumferential surface of the heat transfer tube exchanges heat with the cooled water inside the heat transfer tube. Through heat exchange, a portion of the refrigerant evaporates, and the unevaporated refrigerant falls to the heat transfer tubes arranged further down. This heat exchange is repeated continuously. The refrigerant that does not evaporate after heat exchange with the water in the lowermost heat transfer tube is stored in the lower part of pressure vessel 10. Thus, a liquid refrigerant pool is formed inside pressure vessel 10. The liquid level of this refrigerant pool is automatically adjusted to a predetermined height. The heat transfer tubes of the flooded heat transfer tube assembly 31 are immersed in the stored liquid refrigerant. Cooling water flowing within the heat transfer tubes exchanges heat with the stored refrigerant. The refrigerant that has exchanged heat with the heat transfer tubes evaporates and is guided upwards from the liquid surface. The refrigerant evaporated in the upper liquid film heat transfer tube assembly 33, the lower liquid film heat transfer tube assembly 32, and the flooded heat transfer tube assembly 31 is guided to the outlet opening 12 (see reference). Figure 1 The refrigerant guided to the outlet opening 12 is discharged to the outside of the pressure vessel 10. The refrigerant discharged to the outside of the pressure vessel 10 is then drawn in and compressed by the turbo compressor.

[0059] According to this embodiment, the following effects are achieved.

[0060] In this embodiment, a mixing section 53 is provided to mix a refrigerant in a two-phase state (gas and liquid), and the refrigerant mixed by the mixing section 53 is supplied to the heat transfer tube assembly 30. Thus, a refrigerant in a state where the gaseous and liquid phases of the refrigerant are mixed in the mixing section 53 is supplied to the heat transfer tube assembly 30. Therefore, the amount of refrigerant supplied to the heat transfer tube assembly 30 can be homogenized. Consequently, the heat exchange efficiency in the heat transfer tube assembly 30 can be improved, thereby enhancing the performance of the evaporator 1.

[0061] In this embodiment, the mixing section 53 is disposed below the connecting section 51 and receives the refrigerant discharged from the connecting section 51. Therefore, when refrigerant is received in the mixing section 53, the gaseous refrigerant and the liquid refrigerant are mixed by the impact. Thus, the gaseous refrigerant and the liquid refrigerant can be mixed more appropriately in the mixing section 53.

[0062] In this embodiment, the opening area of ​​the inlet 53a of the mixing section 53 is larger than the opening area of ​​the outlet 51a of the connecting section 51. This allows for the appropriate introduction of refrigerant into the mixing section 53. Consequently, the gaseous refrigerant and the liquid refrigerant can be more appropriately mixed in the mixing section 53.

[0063] Furthermore, the present invention is not limited to the above-described embodiments, and appropriate modifications can be made without departing from its spirit.

[0064] For example, in the above embodiment, an example of a component with a hemispherical shape for the mixing section 53 has been described, but the present invention is not limited thereto. For example, as Figure 5 and Figure 6 As shown, the mixing section can be cylindrical. In the cylindrical mixing section 53A, the opening area of ​​the inlet opening 53Aa is approximately the same as the area of ​​the bottom surface 53Ab.

[0065] Furthermore, the mixing section can be conical or frustum-shaped. It can also be pyramidal or frustum-shaped, or a combination thereof. However, as long as the mixing section has a cross-sectional shape that remains unchanged throughout the entire vertical region or a shape whose cross-sectional area decreases downwards, it can properly mix the refrigerant.

[0066] Furthermore, for example, in the above embodiment, an example of the application of the present invention was described in an evaporator in which the refrigerant mixed by the mixing section is supplied to the manifold 54 and the refrigerant is sprayed from the manifold 54 toward the heat transfer tube assembly, but the evaporator to which the present invention is applicable is not limited to the evaporator described above.

[0067] For example, such as Figure 7 As shown, the present invention can be applied in an evaporator 1 in which a tray 60 is provided instead of a manifold 54. The supply device 50B provided in the evaporator 1 supplies the refrigerant mixed by the mixing section 53A to the tray 60 (refer to arrow A3) which is separately provided below the mixing section 53A, and causes the refrigerant to drip from a plurality of holes formed on the bottom surface of the tray 60 toward the heat transfer tube assembly 30 (refer to arrow A4).

[0068] Thus, this invention can be applied even to tray-type or spray-type evaporators.

[0069] The evaporator described in the above-described embodiments can be understood as follows, for example.

[0070] The evaporator according to the first aspect of the present invention comprises: a heat transfer tube assembly 30 having a plurality of heat transfer tubes through which a heat exchange medium flows; an inlet section 20, 51 for introducing a refrigerant in a gas-liquid two-phase state; a mixing section 53 for being supplied with the refrigerant introduced by the inlet section and mixing the supplied refrigerant; and a supply section 54 for supplying the refrigerant mixed by the mixing section to the heat transfer tube assembly.

[0071] In the above structure, a mixing section is provided for a refrigerant in a mixed gas-liquid two-phase state, and the refrigerant mixed in the mixing section is supplied to the heat transfer tube assembly. Thus, a refrigerant in a mixed state of gaseous and liquid phases in the mixing section is supplied to the heat transfer tube assembly. Therefore, the amount of refrigerant supplied to the heat transfer tube assembly can be homogenized. Consequently, the heat exchange efficiency in the heat transfer tube assembly can be improved, thereby enhancing the performance of the evaporator.

[0072] In the second aspect of the present invention, the evaporator described in the first aspect has a mixing section disposed below the inlet section and receiving refrigerant discharged from the inlet section.

[0073] In the above structure, the mixing section is located below the inlet section and receives the refrigerant discharged from the inlet section. Therefore, when the refrigerant is received in the mixing section, the gaseous refrigerant and the liquid refrigerant are mixed by the impact. Thus, the gaseous and liquid refrigerant can be mixed more appropriately in the mixing section.

[0074] In the third aspect of the present invention, the evaporator has, in the first or second aspect described above, a discharge port 51a for discharging the refrigerant in the inlet section, and a mixing section has an inlet port 53a for introducing the refrigerant discharged from the inlet section, wherein the opening area of ​​the inlet port is larger than the opening area of ​​the discharge port.

[0075] In the above structure, the opening area of ​​the inlet of the mixing section is larger than the opening area of ​​the outlet of the inlet. This allows for the appropriate introduction of refrigerant into the mixing section. Therefore, the gaseous and liquid phases of the refrigerant can be mixed more effectively in the mixing section.

[0076] Symbol Explanation

[0077] 1-Evaporator, 10-Pressure vessel, 11-Cylindrical section, 12-Outlet opening, 13-Inlet opening, 20-Refrigerant inlet pipe (introducing section), 21-First horizontal pipe, 22-Second horizontal pipe, 23-Vertical pipe, 24-Third horizontal pipe, 25-Fourth horizontal pipe, 26-Fifth horizontal pipe, 27-Supply pipe, 30-Heat transfer tube assembly, 31-Flooded heat transfer tube assembly, 32-Lower liquid film heat transfer tube assembly 33-Upper liquid film heat transfer tube assembly, 40-Cover, 50-Supply device, 50B-Supply device, 51-Connecting part (inlet part), 51a-Outlet, 52-Rectangular part, 52a-Flow path part, 52b-Small diameter part, 53-Mixing part, 53A-Mixing part, 53Aa-Inlet opening, 53Ab-Bottom surface, 53a-Inlet, 53b-Bottom surface, 54-Manifold (supply part), 60-Tray.

Claims

1. An evaporator comprising: a heat transfer tube group having a plurality of heat transfer tubes through which a heat exchange medium flows inside; an introduction portion that introduces refrigerant in a gas-liquid two-phase state; a mixing portion that is supplied with refrigerant introduced by the introduction portion and mixes the supplied refrigerant; and a supply portion that supplies refrigerant mixed by the mixing portion to the heat transfer tube group.

2. The evaporator according to claim 1, wherein the mixing portion is provided below the introduction portion and receives refrigerant discharged from the introduction portion.

3. The evaporator according to claim 1 or 2, wherein the introduction portion has a discharge port that discharges the refrigerant, the mixing portion has an introduction port that introduces refrigerant discharged from the introduction portion, and an opening area of the introduction port is larger than an opening area of the discharge port. ​ ​ ​ ​ ​ ​ ​ ​

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