Method for manufacturing a porous body-containing pipe

Abstract

To provide a porous body-including pipe that has sufficiently high heat-exchanging and filtering performances and can suppress the pressure loss of fluid flowing through an interior low, and a method of manufacturing such a porous body-including pipe.SOLUTION: A porous body-including pipe comprises a pipe body 11 and porous sintered bodies 20 disposed within the pipe body 11, in which a plurality of porous sintered bodies 20 are disposed with spacing in an extending direction of the pipe body 11, the porous sintered bodies 20 and space portions 15 where no porous sintered bodies 20 are disposed are alternately disposed in the extending direction of the pipe body 11, and the pipe body 11 and the porous sintered bodies 20 are sinter-joined together.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention provides a pipe body and a porous sintered body disposed inside the pipe body. Many The present invention relates to a method for producing a porous body-containing pipe. [Background technology]

[0002] Conventionally, porous sintered bodies made of metals have been used in filters, electrode assemblies, sound-absorbing materials, heat exchanger materials, etc. because of their high specific surface area and high open porosity. For example, Patent Document 1 discloses an underground heat exchange pipe in which a metal tube is filled with a metal porous body that is continuously connected in three dimensions. Furthermore, Patent Document 2 discloses that the metal porous body is used as a filter material for removing soot from the exhaust gas of a diesel engine, or as a filter for a dust collector for combustion gases in incinerators and thermal power plants.

[0003] Here, Patent Document 3 discloses that by using Mg as a sintering aid when sintering aluminum fibers, a porous aluminum sintered body having high porosity and sufficient strength is produced. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-095529 A [Patent Document 2] JP 2004-300526 A [Patent Document 3] JP 2016-194117 A Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, as disclosed in Patent Documents 1 and 2, in heat exchangers and filters having a structure in which a porous metal body is inserted inside a pipe, it is required to reduce the pressure loss of the fluid flowing inside the pipe. In general, in order to reduce pressure loss, it is necessary to increase the porosity of the metal porous body. However, when the porosity is increased, the opening diameter of the pores increases, which may result in a decrease in heat exchange performance and filtering performance.

[0006] The present invention has been made in light of the above circumstances, and provides a filter that has sufficiently high heat exchange performance and filter performance and is capable of suppressing the pressure loss of the fluid flowing inside to a low level. Many The object of the present invention is to provide a method for producing a porous body-containing pipe. [Means for solving the problem]

[0014] The method for producing a porous body-containing pipe of the present invention comprises the steps of: The pipe body and the porous sintered body disposed inside the pipe body are arranged at intervals in the extending direction of the pipe body, the porous sintered bodies and spaces in which the porous sintered bodies are not disposed are arranged alternately in the extending direction of the pipe body, and the pipe body and the porous sintered bodies are sinter-bonded. This method for manufacturing a porous body-containing pipe includes a filling step for filling the inside of the pipe body with sintering raw materials and sintering aids that will become the porous sintered body, and filling the area that will become the space with a mixture of a water-soluble salt and a sintering aid; a sintering step for sintering the sintering raw materials to form the porous sintered body, and sintering-bonding the porous sintered body and the pipe body; and a washing step for circulating water through the inside of the pipe body and discharging the salt to the outside of the pipe body after the sintering step.

[0015] According to this method for manufacturing a porous body-containing pipe, the sintering raw material and sintering aid are filled, and the region that will become the space is filled with a mixture of a water-soluble salt and a sintering aid. After sintering, water is circulated inside the pipe body and the salt is discharged to the outside of the pipe body. Therefore, in the sintering process, a porous sintered body is formed at a predetermined position in the extension direction of the pipe body, and this porous sintered body and the pipe body are sintered and bonded to each other. In addition, the regions that will become the spaces are filled with water-soluble salt and the salt is removed by washing after the sintering process, so that spaces can be reliably formed between the porous sintered bodies. Furthermore, since the area that becomes the space is filled with a water-soluble salt and a sintering aid, the sintering aid filled together with the sintering raw material can be prevented from being adsorbed by the salt during the sintering process. By allowing the sintering aid to act sufficiently, the sintering of the sintering raw material is promoted, making it possible to form a high-strength porous sintered body and to firmly sinter-bond the porous sintered body to the pipe body.

[0016] Here, in the method for producing a porous body-containing pipe of the present invention, the content of the sintering aid in the mixture is preferably 0.5 mass % or more. In this case, since the content of the sintering aid in the mixture is 0.5 mass% or more, the sintering aid filled together with the sintering raw material can be further prevented from being adsorbed by the salt, allowing the sintering aid to act more fully.

[0017] In the method for producing a porous body-containing pipe of the present invention, the salt is preferably sodium chloride. In this case, since the salt is composed of sodium chloride, it can be easily discharged to the outside of the pipe body by washing water in the washing step. In addition, since sodium chloride is inexpensive, the above-mentioned porous body-containing pipe can be manufactured at low cost.

[0018] In the method for producing a porous body-containing pipe of the present invention, the pipe body and the porous sintered body are preferably made of aluminum or an aluminum alloy. In this case, since the pipe body and the porous sintered body are made of aluminum or an aluminum alloy which has excellent sintering properties, a high-strength porous sintered body can be formed and the porous sintered body and the pipe body can be firmly sintered together.

[0019] In the method for producing a porous body-containing pipe of the present invention, the sintering aid is preferably magnesium or zinc. In this case, the pipe body and the porous sintered body are made of aluminum or an aluminum alloy, and the sintering aid is magnesium or zinc, so that the sintering of the sintering raw materials is promoted, a high-strength porous sintered body can be formed, and the porous sintered body and the pipe body can be firmly sintered together. Effect of the Invention

[0020] According to the present invention, the heat exchange performance and the filter performance are sufficiently high, and the pressure loss of the fluid flowing inside can be suppressed to a low level. Many A method for producing a porous body-containing pipe can be provided. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a schematic explanatory diagram of a porous body-containing pipe according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic explanatory diagram of a porous sintered body provided in a porous body-containing pipe according to an embodiment of the present invention. [Diagram 3] 1 is an observation photograph of a cut state of a porous body-containing pipe according to an embodiment of the present invention. [Figure 4] FIG. 2 is a flow diagram showing a method for producing a porous body-containing pipe according to an embodiment of the present invention. [Diagram 5] FIG. 2 is an explanatory diagram of a method for producing a porous body-containing pipe according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, a porous body-containing pipe according to an embodiment of the present invention and a method for producing the porous body-containing pipe will be described with reference to the accompanying drawings. The porous body-containing pipe 10 of this embodiment is used, for example, as a heat exchanger and a filter member.

[0023] As shown in FIG. 1, a porous body-containing pipe 10 according to this embodiment has a structure including a pipe body 11 and a porous sintered body 20 disposed inside the pipe body 11. As shown in FIG. 1, in this embodiment, a plurality of porous sintered bodies 20 are arranged at intervals in the extending direction of the pipe body 11, and the porous sintered bodies 20 and spaces 15 in which the porous sintered bodies 20 are not arranged are arranged alternately in the extending direction of the pipe body 11. In other words, the plurality of porous sintered bodies 20 are arranged intermittently in the extending direction of the pipe body 11.

[0024] In the porous body-containing pipe 10 of this embodiment, the pipe body 11 and the porous sintered body 20 are sinter-bonded. In this embodiment, it is preferable that a sintering aid is present at the joint between the pipe body 11 and the porous sintered body 20. The sintering aid is used when sintering the porous sintered body 20. In this embodiment, the pipe body 11 and the porous sintered body 20 are made of aluminum or an aluminum alloy, and magnesium or zinc is used as a sintering aid.

[0025] 2, the porous sintered body 20 is formed by sintering a plurality of aluminum base materials 21 into one body. In this embodiment, aluminum fibers are used as the aluminum base material 21. It is preferable that the diameter R of the aluminum fibers is within a range of 0.02 mm or more and 1.0 mm or less, and that the ratio L / R of the length L to the diameter R is within a range of 4 or more and 2500 or less.

[0026] In this embodiment, the porosity P of the porous sintered body 20 is preferably set within the range of 65% to 90%. The porosity P (apparent porosity) of the porous sintered body 20 is expressed as the mass m (g) and the volume V (cm 3 ), the true density d (g / cm 3 ) and calculate it by the following formula. 3) can be measured by the underwater method using a precision balance. Porosity P(%)=(1-(m÷(V×d)))×100

[0027] In this embodiment, it is preferable that the inner peripheral surface of the space 15 of the pipe body 11 where the porous sintered body 20 is not disposed is uneven. Fig. 3 is an observation photograph of the porous body-containing pipe 10 of this embodiment cut at the space 15. As shown in Fig. 3, it is confirmed that the inner peripheral surface of the space 15 is not a smooth surface but has unevenness.

[0028] Next, a method for producing the porous body-containing pipe 10 according to this embodiment will be described with reference to FIGS.

[0029] (Filling process S01) First, as shown in Fig. 5, a pipe body 11 is prepared, and a carbon spacer 40 is placed at one end opening (the lower end opening in Fig. 5) of the pipe body 11. Then, the sintering raw material 31 that will become the porous sintered body 20 is filled into the inside of the pipe body 11 from the other opening (the upper end opening in Fig. 5) of the pipe body 11, together with a sintering aid, and a mixture 35 of a water-soluble salt and a sintering aid is filled into the region that will become the space 15.

[0030] In this embodiment, the sintering raw material 31 is aluminum fiber, and magnesium is used as a sintering aid that is filled together with the sintering raw material 31 . The content of magnesium as a sintering aid is preferably within a range of 0.5 mass % to 15 mass %, with the total amount of the sintering raw material 31 and the sintering aid being 100 mass %.

[0031] In this embodiment, sodium chloride is used as the water-soluble salt constituting the mixture 35, and magnesium is used as the sintering aid constituting the mixture 35. Here, the salt and the sintering aid may be mixed uniformly, or the salt and the sintering aid may be laminated in layers. Here, the content of the sintering aid (magnesium) in the mixture 35 is preferably 5 mass% or more, with the mixture 35 being 100 mass%. There is no particular upper limit, but it is preferably 20 mass% or less. Moreover, the content of the sintering aid (magnesium) in the mixture 35 is preferably equal to or greater than the amount of the sintering aid filled together with the sintering raw material 31 .

[0032] (Sintering process S02) Next, sintering is performed with the sintering raw material 31 and the mixture 35 filled in. In this sintering step S02, the aluminum fibers, which are the sintering raw material 31, are bonded to each other to form the porous sintered body 20, and the porous sintered body 20 and the pipe body 11 are sinter-bonded to each other. Here, it is preferable that the sintering temperature is within a range of 565° C. to 655° C., the holding time at the sintering temperature is within a range of 0.5 hours to 2 hours, and the atmosphere is an argon atmosphere.

[0033] In this sintering step S02, by mixing magnesium as a sintering aid into the mixture 35, the sintering aid (magnesium) filled together with the sintering raw material 31 is prevented from being adsorbed by the salt of the mixture 35 when heated, and the magnesium sintering aid promotes sintering between the aluminum fibers which are the sintering raw material 31 and between the porous sintered body 20 and the inner surface of the pipe body 11. Furthermore, the sintering aid disposed in the region that will become the space 15 reacts with the inner surface of the pipe body 11, so that projections and recesses are formed on the inner peripheral surface of the space 15.

[0034] (Cleaning process S03) Next, after the sintering step S02, the carbon spacer 40 is removed, and cleaning water is circulated inside the pipe body 11 to dissolve the water-soluble salt (sodium chloride in this embodiment) that constitutes the mixture 35 in the cleaning water and discharge it to the outside of the pipe body 11.

[0035] By the above-mentioned steps, a plurality of porous sintered bodies 20 are intermittently arranged in the extending direction of the pipe body 11, and the porous body-containing pipe 10 of this embodiment is manufactured.

[0036] According to the porous body-containing pipe 10 of this embodiment configured as described above, a plurality of porous sintered bodies 20 are arranged at intervals in the extension direction of the pipe body 11, and the porous sintered bodies 20 and the space portions 15 in which the porous sintered bodies 20 are not arranged are arranged alternately in the extension direction of the pipe body 11, thereby making it possible to reduce the pressure loss of the fluid flowing inside the pipe body 11. Furthermore, since the porous sintered bodies 20 and the pipe body 11 are sintered together, even if the porous sintered bodies 20 are arranged intermittently with spaces between them, the porous sintered bodies 20 can be firmly fixed in place.

[0037] In this embodiment, if a sintering aid is present at the joint between the pipe body 11 and the porous sintered body 20, the sintering is promoted by the sintering aid when the pipe body 11 and the porous sintered body 20 are sintered together, so that the pipe body 11 and the porous sintered body 20 are firmly bonded together, and the porous sintered body 20 can be fixed even more firmly.

[0038] In the present embodiment, when the pipe body 11 and the porous sintered body 20 are made of aluminum or an aluminum alloy, they are lightweight and have excellent thermal conductivity, and are particularly suitable as a heat exchanger. Furthermore, since aluminum or an aluminum alloy has relatively excellent sinterability, it is possible to form a high-strength porous sintered body 20 and to firmly bond the pipe body 11 and the porous sintered body 20 together.

[0039] Furthermore, in this embodiment, the pipe body 11 and the porous sintered body 20 are made of aluminum or an aluminum alloy, and when magnesium or zinc as a sintering aid is present at the joint between the pipe body 11 and the porous sintered body 20, the sintering is reliably promoted by the sintering aid magnesium or zinc, the pipe body 11 and the porous sintered body 20 are firmly bonded together, and the porous sintered body 20 can be fixed even more firmly.

[0040] In this embodiment, when the porous sintered body 20 is a sintered body of aluminum fibers, the porous sintered body 20 has a sufficient porosity, and the pressure loss can be further reduced.

[0041] Furthermore, in this embodiment, if unevenness is formed on the inner surface of the space portion 15, the unevenness will cause the fluid flowing inside to become turbulent, making it possible to further improve the heat exchange performance and filter performance.

[0042] According to the manufacturing method of the porous body-containing pipe of this embodiment, the sintering raw material 31 and sintering aid are filled, and the region that will become the space 15 is filled with a mixture 35 of a water-soluble salt and a sintering aid. After sintering this, water is circulated inside the pipe body 11 and the water-soluble salt is discharged to the outside of the pipe body 11. Therefore, in the sintering step S02, the porous sintered body 20 can be formed at a predetermined position in the extension direction of the pipe body 11, and this porous sintered body 20 and the pipe body 11 can be sintered and bonded to each other.

[0043] In addition, the area that becomes the space 15 is filled with water-soluble salt, and the salt is discharged by circulating cleaning water after the sintering process, so that the space 15 can be reliably formed between the multiple porous sintered bodies 20. Furthermore, since the region that becomes the space 15 is filled with a mixture 35 of a water-soluble salt and a sintering aid, the sintering aid filled together with the sintering raw material 31 in the sintering step S02 can be prevented from being adsorbed by the salt filled in the space 15. By allowing the sintering aid filled together with the sintering raw material 31 to act sufficiently, the sintering of the sintering raw material 31 is promoted, a high-strength porous sintered body 20 can be formed, and the porous sintered body 20 and the pipe body 11 can be firmly sintered together.

[0044] In this embodiment, when the content of the sintering aid in the mixture 35 is 0.5 mass% or more, the sintering aid filled together with the sintering raw material 31 can be further prevented from being adsorbed by the salt, allowing the sintering aid to act more fully, promoting the sintering of the sintering raw material 31, enabling a high-strength porous sintered body 20 to be formed, and enabling the porous sintered body 20 and the pipe body 11 to be firmly sintered together.

[0045] In this embodiment, when the water-soluble salt is sodium chloride, sodium chloride can be easily discharged to the outside of the pipe body 11 by dissolving it in the cleaning water in the cleaning step S03. In addition, since sodium chloride is inexpensive, the porous body-containing pipe 10 of this embodiment can be manufactured at low cost.

[0046] Furthermore, in this embodiment, when the pipe body 11 and the porous sintered body 20 are made of aluminum or an aluminum alloy, a porous sintered body 20 having excellent sinterability and high strength can be formed, and the porous sintered body 20 and the pipe body 11 can be firmly sintered and bonded together.

[0047] In addition, in this embodiment, when the pipe body 11 and the porous sintered body 20 are made of aluminum or an aluminum alloy and the sintering aid is magnesium or zinc, the sintering of the sintering raw material 31 is promoted, a high-strength porous sintered body 20 can be formed, and the porous sintered body 20 and the pipe body 11 can be firmly sintered together.

[0048] Although the embodiment of the present invention has been described above, the present invention is not limited to this, and can be modified as appropriate without departing from the technical concept of the invention. In this embodiment, a porous body-containing pipe having the structure shown in Figure 1 has been described as an example, but the present invention is not limited to this. It is sufficient that a plurality of porous sintered bodies are arranged at intervals in the extension direction of the pipe body, the porous sintered bodies and spaces in which no porous sintered bodies are arranged alternately in the extension direction of the pipe body, and the pipe body and the porous bodies are sintered and bonded to each other. For example, the pipe body may be a curved pipe, as long as the porous sintered bodies are disposed at intervals in the extending direction of the pipe body. EXAMPLES

[0049] The results of experiments carried out to confirm the effects of the present invention will be described below.

[0050] First, a pipe (inner diameter 18 mm, outer diameter 20 mm, length 100 mm) made of A1070 was prepared. Furthermore, aluminum fibers (made of A1050) having a diameter R of 0.25 mm or more and 0.35 mm or less and a ratio L / R of the length L to the diameter R of 15 or more and 120 or less were prepared as a sintering raw material. Magnesium was prepared as a sintering aid. As a water-soluble salt, sodium chloride was prepared.

[0051] The inside of the pipe was filled with the sintering raw material (aluminum fiber) and the sintering aid (magnesium), and also with a mixture of water-soluble salt (sodium chloride) and the sintering aid (magnesium). At this time, the content of magnesium filled together with the aluminum fibers was 1 mass%, with the total of the sintering raw material and the sintering aid being 100 mass%. The magnesium content in the mixture and the mixed state of sodium chloride and magnesium are shown in Table 1.

[0052] Next, sintering was performed in an argon atmosphere at 640°C for 1 hour. After that, washing water was circulated inside the pipe body. In this manner, a porous body-containing pipe was produced.

[0053] The obtained porous pipe was evaluated as follows with respect to the sintering state between the porous sintered body and the pipe body, and the state of the inner surface of the pipe body.

[0054] (Sintering state between porous sintered body and pipe body) The aluminum fibers arranged inside the pipe were pulled with tweezers to confirm whether they could be removed. If the weight of the removed aluminum fibers was 50% or more of the weight of the aluminum fibers inserted inside the pipe, it was evaluated as "X", and if the weight of the removed aluminum fibers was less than 50%, it was evaluated as "O". The evaluation results are shown in Table 1.

[0055] (Unevenness of the inner surface of the pipe) The pipe was cut at the space where no aluminum fibers were arranged, and the thickness of the pipe at the space was measured at 10 points in the circumferential direction using a vernier caliper, and the maximum and minimum differences were measured. The measurement results are shown in Table 1.

[0056] [Table 1]

[0057] In the comparative example in which only a water-soluble salt (sodium chloride) was filled, the porous sintered body and the pipe body were not sufficiently sintered and bonded, and the sintering of the porous sintered body itself did not progress sufficiently.

[0058] In contrast, in Example 1-4 of the present invention, which was filled with a mixture of water-soluble salt (sodium chloride) and sintering aid (magnesium), the porous sintered body and the pipe body were sufficiently sintered and bonded, and the sintering of the porous sintered body itself had progressed sufficiently.

[0059] From the above, it has been confirmed that the present invention can provide a porous body-containing pipe that has sufficiently high heat exchange performance and filtering performance and is capable of reducing the pressure loss of the fluid flowing through it, as well as a method for manufacturing this porous body-containing pipe. [Explanation of symbols]

[0060] 10. Porous material-containing pipe 11 Pipe body 15 Space section 20 Porous sintered body

Claims

1. A method for manufacturing a porous body-containing pipe, comprising: a pipe body; and a porous sintered body disposed inside the pipe body, a plurality of the porous sintered bodies are disposed at intervals in the extension direction of the pipe body, the porous sintered bodies and spaces in which the porous sintered bodies are not disposed are disposed alternately in the extension direction of the pipe body, and the pipe body and the porous sintered bodies are sinter-bonded to each other, comprising: a filling step of filling the inside of the pipe with sintering raw materials and a sintering aid that will become the porous sintered body, and filling a mixture of a water-soluble salt and a sintering aid into an area that will become the space; a sintering step of sintering a sintering raw material to form the porous sintered body and sinter-bonding the porous sintered body and the pipe body; a washing step of circulating water through the inside of the pipe body after the sintering step to discharge the salt to the outside of the pipe body; A method for producing a porous body-containing pipe, comprising:

2. 2. The method for producing a porous body-containing pipe according to claim 1, wherein the content of the sintering aid in the mixture is 0.5 mass % or more.

3. 3. The method for producing a porous body-containing pipe according to claim 1, wherein the salt is sodium chloride.

4. 4. The method for producing a porous body-containing pipe according to claim 1, wherein the pipe body and the porous sintered body are made of aluminum or an aluminum alloy.

5. 5. The method for producing a porous body-containing pipe according to claim 4, wherein the sintering aid is magnesium or zinc.

Images