JP2007046880A - Refrigerant piping structure for refrigeration unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide refrigerant piping structure for a refrigeration unit capable of preventing surely a defect of brazing material plugging from being generated. <P>SOLUTION: In this refrigerant piping structure for the refrigeration unit, a brazing material reserving space 21 for reserving an excess of brazing material 20 is formed between an outer circumferential face in a tip part 6 of a refrigerant pipe 1 and a diameter expansion part 4 of a joint pipe 2, by overhanging the tip part 6 of the refrigerant pipe 1 into the diameter expansion part 4 adjacent to a tip part 3 of the joint pipe 2, while fitting the tip part 3 of the joint pipe 2 around an end part 5 of the refrigerant pipe 1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a refrigerant pipe structure of a refrigeration apparatus formed by connecting a plurality of refrigerant pipes.

Conventionally, when connecting refrigerant pipes in a refrigeration apparatus such as an air conditioner or a heat pump type hot water heater, for example, as shown in FIG. In the state in which the refrigerant pipes 50 and 52 are brazed with a brazing material 54 interposed between the outer peripheral surface of the tip end portion 51 and the inner peripheral surface of the tip enlarged diameter portion 53 in a state of being inserted into the tip end portion 51. is there. (For example, refer to Patent Document 1).
JP-A-9-310888

  However, in the conventional refrigerant piping structure, when the amount of the brazing material 54 at the time of brazing is large, the surplus brazing material 54 wraps around the pipes of the refrigerant pipes 50 and 52, thereby reducing the pressure loss during refrigerant transportation. In some cases, wax clogging defects such as inviting or clogging in the pipe may occur.

In particular, in a refrigeration apparatus that forms a high-pressure supercritical refrigerant cycle using carbon dioxide (CO ₂ ) as a refrigerant, the pressure resistance is increased by increasing the thickness of the refrigerant pipe or reducing the outer diameter. When small refrigerant pipes are connected to each other by brazing as in the prior art, there has been a drawback in that defective solder clogging is likely to occur.

  The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to provide a refrigerant piping structure for a refrigeration apparatus that can reliably prevent the occurrence of defective wax clogging. .

  In order to solve the above-described problem, the refrigerant piping structure of the refrigeration apparatus of the present invention is formed by connecting a plurality of refrigerant tubes 1, 2,... While the front end portion 3 of the refrigerant pipe 2 is externally fitted, the front end portion 6 of the one refrigerant pipe 1 is projected into the enlarged diameter portion 4 continuous with the front end portion 3 of the other refrigerant pipe 2, Between the outer peripheral surface of the tip portion 6 of the one refrigerant tube 1 and the inner peripheral surface of the enlarged diameter portion 4 of the other refrigerant tube 2, the end portion 5 of the one refrigerant tube 1 and the other refrigerant tube. 2 is characterized in that a wax storage space 21 is formed for storing an excess of the brazing material 20 interposed between the two tip portions 3.

  Specifically, the inner cross-sectional area S1 around the tip opening 7 of the one refrigerant tube 1 in the enlarged diameter portion 4 of the other refrigerant tube 2 is defined as 3. Less than 9 times.

Further, the outer peripheral surface of the tip portion 6 of the one refrigerant tube 1, the inner peripheral surface of the enlarged diameter portion 4 of the other refrigerant tube 2, and the tube shaft direction orthogonal to the tip surface 8 of the one refrigerant tube 1. The volume of the wax storage space 21 surrounded by the surface 22 extending along the direction of the movement is 10 mm ³ or more.

  In the refrigerant piping structure of the refrigeration apparatus according to the present invention, a solder storage space for storing excess brazing material is formed at the connecting portion between one refrigerant pipe and the other refrigerant pipe, so that the outer diameter of the pressure-resistant strength is increased. Even when small refrigerant pipes are connected to each other, it is possible to prevent the brazing material from entering the pipes and to reliably prevent the occurrence of the clogging.

  Also, by setting the ratio of the area at the front end opening of one refrigerant pipe and the inner cross-sectional area of the enlarged diameter part of the other refrigerant pipe to an appropriate value, the flow path from one refrigerant pipe to the other refrigerant pipe can be expanded. Since it is moderate, even if a two-phase refrigerant flows during defrosting, it is possible to reliably suppress the generation of noise due to rapid expansion of the flow path.

  Furthermore, since the volume of the brazing space is set to an appropriate value so that the brazing material can be stably accumulated in the brazing space, it is possible to reliably prevent the brazing material from entering the pipe.

Next, specific embodiments of the refrigerant piping structure of the refrigeration apparatus of the present invention will be described in detail with reference to the drawings. FIG. 1 is a longitudinal sectional view of a refrigerant pipe structure according to an embodiment of the present invention, in which 1 is one refrigerant pipe constituting a supercritical refrigerant cycle of a heat pump type hot water heater using, for example, CO ₂ as a refrigerant, Reference numeral 2 denotes a joint pipe as the other refrigerant pipe for connecting the refrigerant pipes 1 and 1 to each other.

  The refrigerant tube 1 is set to have a small outer diameter and has a pressure resistance that can withstand a high-pressure refrigerant. Specifically, in the refrigerant pipe 1, as shown in FIG. 2, for example, the thickness is set to 0.5 mm, the outer diameter is set to 4 mm, and the inner diameter is set to 3 mm.

  The joint pipe 2 is formed by integrally forming both straight tubular tip portions 3 and 3 and an enlarged diameter portion 4 connecting the tip portions 3 and 3. The tip portions 3 and 3 of the joint pipe 2 are set to have a thickness of 1 mm, an outer diameter of about 6 mm, and an inner diameter of about 4 mm, for example, and are fitted on the end portions 5 and 5 of the refrigerant tubes 1 and 1, respectively. It is like that.

  The diameter-enlarged portion 4 of the joint pipe 2 includes tapered rising portions 10 and 10 that are continuous with both end portions 3 and 3, and a straight tubular intermediate portion 11 that connects the rising portions 10 and 10. The rising portions 10 and 10 are set to have a thickness of 1 mm, for example, and are formed such that the outer diameter and the inner diameter gradually increase as the distance from the tip portions 3 and 3 increases. For example, the intermediate portion 11 has a thickness of 1 mm, an outer diameter of 7.94 mm, and an inner diameter of 5.94 mm.

  When connecting the one refrigerant pipe 1 and the joint pipe 2, as shown in FIG. 2, the end part 3 of the joint pipe 2 is externally fitted to the end part 5 of the refrigerant pipe 1. The distal end portion 6 protrudes into the enlarged diameter portion 4 of the joint pipe 2, and the distal end opening 7 faces the enlarged diameter portion 4. Then, both pipes 1 and 2 are brazed with a brazing material 20 interposed between the outer peripheral surface of the end portion 5 of the refrigerant pipe 1 and the inner peripheral surface of the distal end portion 3 of the joint pipe 2.

  In this connected state, a brazing reservoir space 21 is formed between the outer peripheral surface of the distal end portion 6 of the refrigerant pipe 1 and the inner peripheral surface of the enlarged diameter portion 4 of the joint pipe 2, and stores an excess amount of the brazing material 20. The brazing material 20 is prevented from wrapping around the pipes 1 and 2 to prevent the occurrence of defective solder clogging.

  However, simply by providing the joint pipe 2 with the enlarged diameter portion 4 and forming the wax accumulation space 21 between the inner peripheral surface of the enlarged diameter portion 4 and the outer peripheral surface of the front end portion 6 of the refrigerant pipe 1, At the time of defrosting, if a two-phase refrigerant mixed with gas and liquid flows from the tip opening 7 of the refrigerant pipe 1 to the enlarged diameter portion 4 of the joint pipe 2, there is a possibility that an abnormal noise is generated due to the rapid expansion of the flow path. is there.

  Therefore, as a countermeasure against such abnormal noise, the inner cross-sectional area S1 around the front end opening 7 of the refrigerant pipe 1 in the intermediate portion 11 of the enlarged diameter portion 4 of the joint pipe 2 is set to 3 of the area S2 in the front end opening 7 of the refrigerant pipe 1. Less than 9 times. As described above, the ratio between the inner cross-sectional area S1 and the area S2 is set when the inner cross-sectional area S1 is 3.9 times the area S2 or more. This is because an abnormal noise is generated when flowing from the pipe to the enlarged diameter portion 4 of the joint pipe 2, whereas the generation of the abnormal noise can be suppressed by making the ratio less than 3.9 times.

  In order to suppress the generation of abnormal noise, it is desirable to reduce the inner diameter difference between the expanded diameter portion 4 of the refrigerant pipe 1 and the joint pipe 2 as much as possible. However, the volume of the wax storage space 21 is reduced accordingly, and this volume is too large. If it becomes smaller, the brazing material 20 cannot be stored well.

Therefore, the outer peripheral surface of the distal end portion 6 of the refrigerant pipe 1, the inner peripheral surface of the enlarged diameter portion 4 of the joint pipe 2 (the inner peripheral surface from the rising portion 10 to a part of the intermediate portion 11), and the distal end of the refrigerant tube 1. The volume of the wax storage space 21 surrounded by the surface 22 extending from the surface 8 along the direction orthogonal to the tube axis direction (the volume of the portion provided with fine dots) is set to 10 mm ³ or more. In this way, the volume of the brazing reservoir space 21 is set because if the volume is less than 10 mm ³ , the brazing filler metal 20 cannot be sufficiently accumulated in the brazing reservoir space 21, and the brazing filler metal is introduced into both pipes 1 and 2. 20 may wrap around, but by setting the volume to 10 mm ³ , the brazing material 20 is stably accumulated in the brazing space 21, and the brazing material 20 wraps around the pipes 1 and 2. This is because it can be eliminated.

  Therefore, in the above refrigerant piping structure, the occurrence of abnormal noise can be reliably suppressed even when the two-phase refrigerant flows at the time of defrosting, while reliably preventing the occurrence of defective clogging.

  FIG. 3 shows a refrigerant piping structure according to another embodiment. The joint pipe 30 in this refrigerant pipe structure has a structure in which two branch pipes 32, 32 are branched from the main pipe 31 in a substantially L shape, and the refrigerant pipe 1 similar to the above is connected to the main pipe 31, A wax accumulation space 34 is formed between the outer peripheral surface of the front end portion 6 of the refrigerant pipe 1 and the inner peripheral surface of the enlarged diameter portion 33 of the main pipe 31. The other branch pipes 32 and 32 are connected to other refrigerant pipes 35 and 35 having an outer diameter larger than that of the refrigerant pipe 1.

  FIG. 4 shows a refrigerant piping structure according to still another embodiment. The joint pipe 40 in this refrigerant pipe structure has a structure in which two branch pipes 42 and 42 are branched from the main pipe 41 in a substantially U shape, and the refrigerant pipe 1 similar to the above is connected to the main pipe 41. A wax accumulation space 44 is formed between the outer peripheral surface of the front end portion 6 of the refrigerant pipe 1 and the inner peripheral surface of the enlarged diameter portion 43 of the main pipe 41. Note that another refrigerant pipe (not shown) is connected to the other branch pipes 42 and 42.

  Although specific embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made within the scope of the present invention. For example, in the above embodiment, the connection between the refrigerant pipe and the joint pipe has been described, but the refrigerant pipe structure of the present invention may be applied when the ends of the refrigerant pipe are simply connected. In addition, each dimension of the refrigerant pipe and the joint pipe, the ratio of the inner cross-sectional area around the refrigerant pipe tip opening in the diameter-expanded portion of the joint pipe and the area of the refrigerant pipe tip opening, and the volume of the wax storage space are not necessarily It is not limited to the above embodiment, but may be appropriately changed according to the specifications of the refrigeration apparatus, the type of refrigerant, and the like.

It is a longitudinal cross-sectional view which shows the refrigerant | coolant piping structure of the freezing apparatus which concerns on one Embodiment of this invention. It is the longitudinal cross-sectional view which expanded the principal part similarly. It is a longitudinal cross-sectional view which shows the refrigerant | coolant piping structure which concerns on another embodiment. It is a longitudinal cross-sectional view which shows the refrigerant | coolant piping structure which concerns on another embodiment. It is a longitudinal cross-sectional view which shows the conventional refrigerant | coolant piping structure.

Explanation of symbols

··· One refrigerant tube, 2, 30, 40 ··· The other refrigerant tube (joint tube), · · · The tip of the other refrigerant tube, 4, 33, 43 · · Expanded portion, · · · One The end of one refrigerant tube, the tip end of one refrigerant tube, the opening of the tip of one refrigerant tube, the tip surface of one refrigerant tube, the brazing material, 21, 34, 44..Lower storage space, 22..Surface, S1..Inner cross-sectional area, S2..Area

Claims (4)

  In the refrigerant piping structure of the refrigeration apparatus formed by connecting a plurality of refrigerant tubes (1), (2),..., The end portion (5) of one refrigerant tube (1) is connected to the tip portion of the other refrigerant tube (2). While fitting (3), the tip (6) of the one refrigerant pipe (1) is placed in the enlarged diameter part (4) continuous with the tip (3) of the other refrigerant pipe (2). The one refrigerant pipe is extended between the outer peripheral surface of the tip (6) of the one refrigerant pipe (1) and the inner peripheral surface of the enlarged diameter part (4) of the other refrigerant pipe (2). A wax storage space (21) for storing an excess of the brazing material (20) interposed between the end (5) of (1) and the tip (3) of the other refrigerant pipe (2) was formed. A refrigerant piping structure for a refrigeration apparatus.   The inner cross-sectional area (S1) around the tip opening (7) of the one refrigerant pipe (1) in the enlarged diameter portion (4) of the other refrigerant pipe (2) is the tip of the one refrigerant pipe (1). The refrigerant piping structure of the refrigeration apparatus according to claim 1, wherein the area (S2) of the opening (7) is less than 3.9 times. The outer peripheral surface of the tip portion (6) of the one refrigerant pipe (1), the inner peripheral surface of the enlarged diameter portion (4) of the other refrigerant pipe (2), and the front end surface of the one refrigerant pipe (1) ( The volume of the wax reservoir space (21) surrounded by a surface (22) extending along a direction orthogonal to the tube axis direction from 8) is set to 10 mm ³ or more. Refrigerant piping structure of refrigeration equipment.   The refrigerant pipe structure of the refrigeration apparatus according to any one of claims 1 to 3, wherein the other refrigerant pipe (2) is a joint pipe for connecting the refrigerant pipes (1) and (1).