Refrigerant piping

Abstract

Provided is refrigerant piping in which it is possible to suppress any corrosion of a brazing material in a piping joint portion in an environment where corrosive gas is present. To achieve the above, this refrigerant piping comprises first piping through the interior of which refrigerant flows, and second piping through the interior of which the refrigerant flows and which is joined to the first piping by brazing. The outside diameter of the second piping is less than the inside diameter of the first piping. A brazing material for the brazing is provided between the outer periphery of the second piping inserted inside the first piping and the inner periphery of the first piping. The refrigerant piping furthermore comprises a neutralizing agent that neutralizes one or both of an acidic gas and an alkaline gas, an adsorbent that adsorbs moisture, and a seal material that covers the outer periphery of the first piping and the outer periphery of the second piping at the joint portion between the first piping and the second piping. The neutralizing agent and the adsorbent are disposed between the seal material and the outer periphery of the second piping.

Description

Refrigerant piping

[0001] The present disclosure relates to refrigerant piping.

[0002] A known refrigeration cycle is formed by connecting a compressor, a condenser, an expansion mechanism, and an evaporator with refrigerant piping, and a flammable refrigerant is sealed in this refrigeration cycle.The interior of the refrigeration cycle is formed by an insulated box with an inner box and an outer box filled with insulating material, and the piping connections between the cycle components that make up the refrigeration cycle are covered with heat-shrink tubing (see, for example, Patent Document 1).

[0003] Japanese Patent Application Publication No. 2001-248950

[0004] However, in the technology disclosed in Patent Document 1, the brazed pipe connection portion is simply covered with a heat-shrinkable tube. Therefore, in an environment where corrosive gases such as sulfur dioxide, hydrogen sulfide, and ammonia are present, these corrosive gases may permeate the heat-shrinkable tube and reach the brazed portion, causing corrosion of the brazing material.

[0005] The present disclosure has been made to solve these problems, and an object of the present disclosure is to provide a refrigerant pipe that can suppress corrosion of the brazing material at the pipe joint in an environment where corrosive gases such as sulfur dioxide, hydrogen sulfide, and ammonia are present.

[0006] The refrigerant piping according to the present disclosure comprises a first pipe through which a refrigerant flows, and a second pipe through which a refrigerant flows and which is joined to the first pipe by brazing, wherein the outer diameter of the second pipe is smaller than the inner diameter of the first pipe, and a brazing material is provided between the outer periphery of the second pipe inserted inside the first pipe and the inner periphery of the first pipe, and further comprises a neutralizing agent that neutralizes one or both of an acidic gas and an alkaline gas, an adsorbent that adsorbs moisture, and a sealing material that covers the outer periphery of the first pipe and the outer periphery of the second pipe at the joint between the first pipe and the second pipe, and the neutralizing agent and the adsorbent are disposed between the sealing material and the outer periphery of the second pipe.

[0007] Advantageous Effects of Invention The refrigerant pipe according to the present disclosure has the advantage of being able to suppress corrosion of the brazing material at the joint portion of the pipe in an environment where corrosive gas is present.

[0008] FIG. 1 is a cross-sectional view schematically showing one example of the configuration of a refrigerant pipe according to embodiment 1. FIG. 2 is a cross-sectional view schematically showing another example of the configuration of a refrigerant pipe according to embodiment 1. FIG. 3 is a cross-sectional view schematically showing the configuration of a first modified example of a refrigerant pipe according to embodiment 1. FIG. 4 is a cross-sectional view schematically showing the configuration of a second modified example of a refrigerant pipe according to embodiment 1. FIG. 5 is a cross-sectional view schematically showing the configuration of a third modified example of a refrigerant pipe according to embodiment 1. FIG. 6 is a cross-sectional view schematically showing the configuration of a fourth modified example of a refrigerant pipe according to embodiment 1. FIG. 7 is a cross-sectional view schematically showing the configuration of a fifth modified example of a refrigerant pipe according to embodiment 1. FIG. 8 is a cross-sectional view schematically showing the configuration of a sixth modified example of a refrigerant pipe according to embodiment 1.

[0009] Embodiments of refrigerant piping according to the present disclosure will be described with reference to the accompanying drawings. In each drawing, identical or corresponding parts are designated by the same reference numerals, and redundant descriptions will be appropriately simplified or omitted. For convenience, the following description may express the positional relationship of each structure based on the illustrated state. Note that the present disclosure is not limited to the following embodiments, and any combination of the embodiments, any modification of any component of each embodiment, or any omission of any component of each embodiment are possible within the scope of the present disclosure.

[0010] Embodiment 1. A first embodiment of the present disclosure will be described with reference to Figures 1 to 8. Figure 1 is a cross-sectional view schematically showing one example of the configuration of a refrigerant pipe. Figure 2 is a cross-sectional view schematically showing another example of the configuration of a refrigerant pipe. Figure 3 is a cross-sectional view schematically showing the configuration of a first modified example of a refrigerant pipe. Figure 4 is a cross-sectional view schematically showing the configuration of a second modified example of a refrigerant pipe. Figure 5 is a cross-sectional view schematically showing the configuration of a third modified example of a refrigerant pipe. Figure 6 is a cross-sectional view schematically showing the configuration of a fourth modified example of a refrigerant pipe. Figure 7 is a cross-sectional view schematically showing the configuration of a fifth modified example of a refrigerant pipe. Figure 8 is a cross-sectional view schematically showing the configuration of a sixth modified example of a refrigerant pipe.

[0011] As shown in Fig. 1, the refrigerant pipe 10 according to this embodiment includes a first pipe 11 and a second pipe 12. The first pipe 11 and the second pipe 12 are hollow cylindrical. A refrigerant flows through the first pipe 11 and the second pipe 12. The first pipe 11 and the second pipe 12 are metal pipes made of, for example, copper, aluminum, or the like.

[0012] The first pipe 11 and the second pipe 12 are joined by brazing. The outer diameter of the second pipe 12 is smaller than the inner diameter of the first pipe 11. The outer diameter of the second pipe 12 may not be constant but may vary along the longitudinal direction of the second pipe 12. Similarly, the inner diameter of the first pipe 11 may not be constant but may vary along the longitudinal direction of the first pipe 11. Therefore, more specifically, the outer diameter of at least the end of the second pipe 12 that is connected to the first pipe 11 is smaller than the inner diameter of at least the end of the first pipe 11 that is connected to the second pipe 12.

[0013] At the joint between the first pipe 11 and the second pipe 12, the second pipe 12 is inserted inside the first pipe 11. A brazing material 20 used for brazing is filled between the outer periphery of the second pipe 12 inserted inside the first pipe 11 and the inner periphery of the first pipe 11. When the first pipe 11 and the second pipe 12 are copper pipes, for example, phosphor copper brazing material or the like is used as the brazing material 20. When the first pipe 11 and the second pipe 12 are aluminum pipes, for example, aluminum brazing material or the like is used as the brazing material 20.

[0014] The refrigerant pipe 10 of this embodiment further includes a sealing material 30. The sealing material 30 continuously covers the outer periphery of the first pipe 11 and the outer periphery of the second pipe 12 at the joint between the first pipe 11 and the second pipe 12. The sealing material 30 is preferably made of a substance having a solubility parameter (Solubility Parameter / SP value) of 10 or less. Specific examples include butyl rubber, natural rubber, styrene-butadiene rubber, chloroprene rubber, polyethylene, and polystyrene.

[0015] The sealing material 30 may be in the form of rubber or tape with a thickness of 1 mm or less. This allows the sealing material 30 to adhere to the brazed portion even if there is some variation in the shape of the brazed portion, which varies from product to product. Furthermore, the sealing material 30 may be fixed with an adhesive to prevent peeling of the sealing material 30.

[0016] The refrigerant pipe 10 of this embodiment further includes a neutralizing agent 41 and an adsorbent 42. The neutralizing agent 41 neutralizes one or both of acidic gases and alkaline gases. The neutralizing agent 41 may be a hydrogen ion concentration buffer. Specific examples of hydrogen ion concentration buffers used for the neutralizing agent 41 include sodium bicarbonate, citric acid, calcium carbonate, etc., or mixtures of these. The adsorbent 42 adsorbs moisture. For example, activated carbon can be used as the adsorbent 42.

[0017] The neutralizing agent 41 and the adsorbent 42 are arranged between the sealing material 30 and the outer periphery of the second pipe 12. In the configuration example shown in FIG. 1, the neutralizing agent 41 and the adsorbent 42 are arranged along the axial direction of the second pipe 12. In the example shown in FIG. 1, the neutralizing agent 41 is arranged closer to the brazing material 20, and the adsorbent 42 is arranged farther from the brazing material 20. The neutralizing agent 41 is adjacent to the brazing material 20. However, this arrangement order is not limited to that shown in FIG. 1. As shown in FIG. 2, the adsorbent 42 may be arranged closer to the brazing material 20, and the neutralizing agent 41 may be arranged farther from the brazing material 20.

[0018] In the refrigerant pipe 10 configured as described above, the brazed pipe joint is covered with the sealant 30, and the neutralizing agent 41 and the adsorbent 42 are filled inside the sealant 30. When gases present outside the refrigerant pipe 10 that corrode the brazing filler metal 20, such as sulfur dioxide, hydrogen sulfide, and ammonia, penetrate the sealant 30 and enter the inside of the sealant 30, the neutralizing agent 41 neutralizes the invading corrosive gas, and the adsorbent 42 adsorbs and removes the water in which the corrosive gas is dissolved. This makes it possible to neutralize and remove the corrosive gas that has penetrated inside the sealant 30 before it reaches the brazing filler metal 20, thereby suppressing corrosion of the brazing filler metal at the pipe joint in an environment where corrosive gas is present. Furthermore, using a substance with a solubility parameter of 10 or less for the sealant 30 makes it difficult for corrosive gases present outside the refrigerant pipe 10, such as sulfur dioxide, hydrogen sulfide, and ammonia, to penetrate the sealant 30, further suppressing corrosion of the brazing filler metal at the pipe joint.

[0019] Next, modified examples of the refrigerant pipe 10 according to this embodiment will be described with reference to Figures 3 to 8. Figure 3 shows a first modified example of the refrigerant pipe 10. In this first modified example, the sealing material 30 has a thick portion 31. The thick portion 31 of the sealing material 30 is a portion whose thickness is greater than the thickness of the sealing material 30 other than the thick portion 31.

[0020] In this first modified example, a portion of the sealing material 30 that is disposed radially outward of the second pipe 12 relative to the neutralizing agent 41 and the adsorbent 42 is the thick portion 31. A portion that is disposed on the opposite side of the second pipe 12 from the first pipe 11 in the axial direction of the second pipe 12 relative to the neutralizing agent 41 and the adsorbent 42 is not the thick portion 31. In other words, the thickness of the portion that is disposed radially outward of the second pipe 12 relative to the neutralizing agent 41 and the adsorbent 42 is greater than the thickness of the portion that is disposed on the opposite side of the second pipe 12 from the first pipe 11 in the axial direction of the second pipe 12 relative to the neutralizing agent 41 and the adsorbent 42.

[0021] According to the first modified example, it is possible to make it difficult for corrosive gas to permeate the sealing material 30 from the radial direction of the second pipe 12 provided with the thick portion 31. This makes it possible to prevent the corrosive gas from permeating the sealing material 30 from the radial direction of the second pipe 12 and passing through only one of the neutralizing agent 41 or the adsorbent 42 to reach the brazing material 20. In other words, the corrosive gas that permeates the sealing material 30 can be guided to pass through both the neutralizing agent 41 and the adsorbent 42 in sequence, making it possible to neutralize and adsorb and remove the corrosive gas that has penetrated inside the sealing material 30. This makes it possible to more reliably prevent corrosion of the brazing material at the pipe joint portion.

[0022] 4 shows a second modified example of the refrigerant pipe 10. In this second modified example, the adsorbent 42 is disposed radially outward of the neutralizing agent 41 in the second pipe 12 and on the opposite side of the second pipe 12 from the first pipe 11 in the axial direction of the neutralizing agent 41. Although not shown in the drawings, in this second modified example, the positions of the neutralizing agent 41 and the adsorbent 42 may be interchanged. That is, the neutralizing agent 41 may be disposed radially outward of the adsorbent 42 in the second pipe 12 and on the opposite side of the second pipe 12 from the first pipe 11 in the axial direction of the adsorbent 42.

[0023] According to the second modification, the corrosive gas can be made to pass through both the neutralizing agent 41 and the adsorbent 42 in sequence, regardless of whether the corrosive gas permeates the sealing material 30 from the radial direction of the second pipe 12 or from the axial direction of the second pipe 12. This makes it possible to neutralize and adsorb / remove the corrosive gas that has penetrated inside the sealing material 30, and more reliably suppress corrosion of the brazing material at the pipe joint.

[0024] FIG. 5 shows a third modified example of the refrigerant pipe 10. In this third modified example, one of the neutralizing agent 41 and the adsorbent 42 is disposed between the outer periphery of the second pipe 12 inserted inside the first pipe 11 and the inner periphery of the first pipe 11. In the illustrated example, the neutralizing agent 41 is filled between the outer periphery of the second pipe 12 inserted inside the first pipe 11 and the inner periphery of the first pipe 11. Here, the brazing material 20 is filled at the innermost position between the outer periphery of the second pipe 12 inserted inside the first pipe 11 and the inner periphery of the first pipe 11. In other words, the brazing material 20 is adjacent to the space through which the refrigerant flows within the refrigerant pipe 10. The neutralizing agent 41 is adjacent to the brazing material 20. The adsorbent 42 is disposed outside the first pipe 11 and between the sealing material 30 and the outer periphery of the second pipe 12. The adsorbent 42 is adjacent to the neutralizing agent 41.

[0025] Although not shown in the drawings, in this third modified example, the positions of the neutralizing agent 41 and the adsorbent 42 may be interchanged. That is, the adsorbent 42 may be filled between the outer periphery of the second pipe 12 inserted inside the first pipe 11 and the inner periphery of the first pipe 11. The neutralizing agent 41 may be disposed outside the first pipe 11, between the sealing material 30 and the outer periphery of the second pipe 12.

[0026] According to the third modification, the corrosive gas that has permeated the sealing material 30 can be reliably passed through both the neutralizing agent 41 and the adsorbent 42 in sequence. This makes it possible to neutralize and adsorb and remove the corrosive gas that has penetrated inside the sealing material 30, and more reliably suppress corrosion of the brazing material at the pipe joint.

[0027] FIG. 6 shows a fourth modified example of the refrigerant pipe 10. In this fourth modified example, both a neutralizing agent 41 and an adsorbent 42 are disposed between the outer periphery of the second pipe 12 inserted inside the first pipe 11 and the inner periphery of the first pipe 11. In the illustrated example, the neutralizing agent 41 is disposed closer to the brazing material 20, and the adsorbent 42 is disposed farther from the brazing material 20. Here, the brazing material 20 is filled at the innermost position between the outer periphery of the second pipe 12 inserted inside the first pipe 11 and the inner periphery of the first pipe 11. In other words, the brazing material 20 is adjacent to the space in the refrigerant pipe 10 through which the refrigerant flows. The neutralizing agent 41 is adjacent to the brazing material 20, and the adsorbent 42 is adjacent to the neutralizing agent 41.

[0028] Although not shown in the drawings, in this fourth modified example, the positions of the neutralizing agent 41 and the adsorbent 42 may be interchanged. That is, the adsorbent 42 may be disposed closer to the brazing filler metal 20, and the neutralizing agent 41 may be disposed farther from the brazing filler metal 20.

[0029] As with the third modification, the fourth modification also ensures that the corrosive gas that has permeated the sealing material 30 passes through both the neutralizing agent 41 and the adsorbent 42 in sequence. This makes it possible to neutralize and adsorb and remove the corrosive gas that has penetrated inside the sealing material 30, and more reliably suppress corrosion of the brazing material at the pipe joint.

[0030] 6 , the sealing material 30 includes a thick portion 31. That is, the thick portion 31 is a portion of the sealing material 30 that is located on the opposite side of the first pipe 11 in the axial direction of the second pipe 12 from the neutralizing agent 41 and the adsorbent 42. By providing such a thick portion 31, it is possible to make it difficult for corrosive gases present outside the refrigerant pipe 10 to pass through the sealing material 30, thereby further suppressing corrosion of the brazing material at the pipe joints. However, in this fourth modified example, the sealing material 30 does not necessarily have to include the thick portion 31.

[0031] FIG. 7 shows a fifth modified example of the refrigerant pipe 10. In this fifth modified example, the refrigerant pipe 10 further includes a partition member 50. The partition member 50 is disposed between the neutralizing agent 41 and the adsorbent 42. Alternatively, as shown in FIG. 7, a partition member 50 may be disposed between the neutralizing agent 41 and the brazing material 20 and between the adsorbent 42 and the sealing material 30. In this fifth modified example, one or both of the neutralizing agent 41 and the adsorbent 42 are powdered. The partition member 50 has a plurality of holes formed therein, each hole having an inner diameter smaller than the particle diameter of the powder. Therefore, the neutralizing agent 41 and the adsorbent 42 cannot pass through the partition member 50. Meanwhile, corrosive gases and water can pass through the partition member 50. The partition member 50 may be, for example, a net, a mesh, or a punched metal.

[0032] 7 shows an example in which a partition member 50 is added to the fourth modified example shown in FIG. 6 described above, i.e., a configuration in which both the neutralizing agent 41 and the adsorbent 42 are filled between the outer periphery of the second pipe 12 inserted inside the first pipe 11 and the inner periphery of the first pipe 11. However, the configuration in which the partition member 50 is added is not limited to that based on the fourth modified example shown in FIG. 6. The partition member 50 may be added to any of the configurations shown in FIGS. 1 to 5.

[0033] According to the fifth modification, when the powdered neutralizing agent 41 and the adsorbent 42 are filled outside the brazing filler material 20 and between the sealing material 30 and the outer periphery of the second pipe 12, the powders can be filled while being pressed down by the partition member 50, and scattering of the powdered neutralizing agent 41 and the adsorbent 42 can be prevented. Therefore, workability during installation can be improved.

[0034] FIG. 8 shows a sixth modified example of the refrigerant pipe 10. In this sixth modified example, the neutralizing agent 41 and the adsorbent 42 are powdered and mixed together. In the configuration example shown in FIG. 8, the entire mixed powdered neutralizing agent 41 and adsorbent 42 is filled between the outer periphery of the second pipe 12 inserted inside the first pipe 11 and the inner periphery of the first pipe 11. However, only a portion of the mixed powdered neutralizing agent 41 and adsorbent 42 may be filled between the outer periphery of the second pipe 12 inserted inside the first pipe 11 and the inner periphery of the first pipe 11, and the other portion may be located outside the first pipe 11 and between the sealing material 30 and the outer periphery of the second pipe 12. Alternatively, the entire mixed powdered neutralizing agent 41 and adsorbent 42 may be located outside the first pipe 11 and between the sealing material 30 and the outer periphery of the second pipe 12. In addition, in the configuration example shown in Figure 8, partition members 50 are provided between the neutralizing agent 41 and the brazing material 20, and between the adsorbent 42 and the sealing material 30, but the partition members 50 do not necessarily have to be provided.

[0035] According to the sixth modification, the powdered neutralizing agent 41 and the adsorbent 42 can be mixed and filled at once outside the brazing material 20 and between the sealing material 30 and the outer periphery of the second pipe 12. This improves the workability during installation.

[0036] The present disclosure can be used for refrigerant piping in which refrigerant pipes are joined together by brazing.

[0037] REFERENCE SIGNS LIST 10 Refrigerant pipe 11 First pipe 12 Second pipe 20 Brazing material 30 Sealing material 31 Thick wall portion 41 Neutralizing agent 42 Adsorbent 50 Partition member

Claims

1. A refrigerant pipe comprising: a first pipe through which a refrigerant flows; and a second pipe through which a refrigerant flows and which is joined to the first pipe by brazing, wherein the outer diameter of the second pipe is smaller than the inner diameter of the first pipe; the brazing material is provided between the outer periphery of the second pipe inserted inside the first pipe and the inner periphery of the first pipe; and further comprising: a neutralizing agent that neutralizes one or both of acidic gases and alkaline gases; an adsorbent that adsorbs moisture; and a sealing material that covers the outer periphery of the first pipe and the outer periphery of the second pipe at the joint between the first pipe and the second pipe, wherein the neutralizing agent and the adsorbent are disposed between the sealing material and the outer periphery of the second pipe.

2. The refrigerant piping described in claim 1, wherein the neutralizing agent and the adsorbent are arranged along the axial direction of the second piping, and the thickness of the sealing material at a portion located radially outward of the second piping relative to the neutralizing agent and the adsorbent is greater than the thickness of a portion located on the opposite side of the first piping in the axial direction relative to the neutralizing agent and the adsorbent.

3. The refrigerant piping according to claim 1, wherein the adsorbent is arranged radially outward of the second piping relative to the neutralizing agent and on the opposite side of the second piping in the axial direction from the first piping relative to the neutralizing agent.

4. The refrigerant piping according to claim 1, wherein the neutralizing agent is arranged radially outward of the second piping relative to the adsorbent and on the opposite side of the second piping in the axial direction from the first piping relative to the adsorbent.

5. The refrigerant piping according to claim 1, wherein one or both of the neutralizing agent and the adsorbent are disposed between the outer periphery of the second piping inserted inside the first piping and the inner periphery of the first piping.

6. The refrigerant pipe according to any one of claims 1 to 5, further comprising a partition member disposed between the neutralizing agent and the adsorbent.

7. The refrigerant pipe according to any one of claims 1 to 6, wherein one or both of the neutralizing agent and the adsorbent are in powder form.

8. The refrigerant pipe according to claim 7, wherein the neutralizing agent and the adsorbent are mixed together.

9. The refrigerant pipe according to any one of claims 1 to 8, wherein the neutralizing agent is sodium bicarbonate, calcium carbonate, or citric acid.

10. A refrigerant pipe according to any one of claims 1 to 9, wherein the solubility parameter of the sealing material is 10 or less.

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