JP2006144557A - Pipe and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pipe having high durability, streamlining property, and silencing property and capable of coping with steam. <P>SOLUTION: This pipe has bellows-like bellows 2, a multiporous pipe 4 arranged to cover the bellows 2 inside the bellows 2 and provided with a plurality of holes 3, and a first supporting member 5 for supporting the multiporous pipe 4 on the upstream side of the bellows 2. Thickness of a layer in a space between the bellows 2 and the multiporous pipe 4 is specified thickness of the layer. By specifying thickness of the multiporous pipe 4 to predetermined thickness, the space between the bellows 2 and the multiporous pipe 4 is used as a Helmholtz resonator for silencing sound in desired frequency band. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a piping and a manufacturing method thereof.

  Bellows-like pipes called bellows are used as exhaust pipe pipes of combustion engines in order to prevent transmission of vibrations of the combustion engine. The above bellows also requires characteristics such as durability and sound deadening. For example, in order to prevent disturbance of the fluid flow and improve durability, the structure does not directly apply the flow to the bellows, or to reduce noise. The inside of the bellows has a double tube structure, and a hole is formed in the inner tube wall, the space with the bellows is used as a Helmholtz resonator, or the bellows and the double tube structure are not in contact with each other to ensure vibration absorption performance. (See Patent Document 1).

JP 09-280041 A

  In the conventional pipe as described above, the structural strength of the double pipe provided inside the bellows is low, there is a risk of resonance with the rotational speed of the turbine, etc., and the separated flow generated downstream of the double pipe There was also a need to suppress backflow. Moreover, as a muffling property, it was possible to mute only a single frequency. Furthermore, not only the exhaust pipe of a combustion engine but also a response to a high-temperature fluid such as steam has been demanded.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a pipe that has high durability, rectification properties, and sound deadening properties, and can cope with steam and the like.

The piping according to the first invention for solving the above-described problems is as follows.
A bellows-shaped bellows provided in the circular tube, a porous tube disposed inside the bellows so as to cover the bellows, and a plurality of holes, and the porous tube as a circular tube on the upstream side of the bellows A first support member to support,
The layer thickness of the space between the bellows and the porous tube is a predetermined layer thickness, the thickness of the porous tube is a predetermined thickness, and the space is a Helmholtz resonator that silences a desired frequency band. Features.

The piping according to the second invention for solving the above problem is as follows.
In the piping according to the first invention,
The porous tube is formed of a material having a high coefficient of thermal expansion,
A second support member for supporting the porous tube on a circular tube on the downstream side of the bellows is provided.

The piping according to the third invention for solving the above problem is as follows.
A bellows-shaped bellows provided in the circular tube, a porous tube disposed inside the bellows so as to cover the bellows, and a plurality of holes, and the porous tube as a circular tube on the upstream side of the bellows A first rectifying member that supports and narrows the flow path from the inner wall surface of the circular tube to the inner wall surface of the porous tube at a predetermined angle; and the porous tube is supported by a circular tube on the downstream side of the bellows; A second rectifying member that expands the flow path at a predetermined angle from the inner wall surface to the inner wall surface of the circular pipe,
The layer thickness of the space between the bellows and the porous tube is a predetermined layer thickness, the thickness of the porous tube is a predetermined thickness, and the space is a Helmholtz resonator that silences a desired frequency band. Features.

The piping according to the fourth invention for solving the above-mentioned problems is
A circular tube having a porous portion provided with a plurality of holes, and a cylindrical tube attached so as to enclose the porous portion outside the porous portion;
The layer thickness of the space between the porous part and the cylindrical tube is a predetermined layer thickness, the thickness of the porous part is a predetermined thickness, and the space is a Helmholtz resonator that silences a desired frequency band It is characterized by.

The piping according to the fifth invention for solving the above-mentioned problems is
In the piping according to the fourth invention,
A separation wall for separating the space is provided in the space between the porous portion and the cylindrical tube.

A pipe according to a sixth invention for solving the above-described problem is
In the piping according to the fifth invention,
A plurality of communication holes are provided in the separation wall.

The piping according to the seventh invention for solving the above-described problems is
In the piping according to the first to sixth inventions,
A rib is provided on the outer surface of the porous tube or the porous portion in the axial direction of the porous tube or the porous portion.

The piping according to the eighth invention for solving the above-described problems is
In the piping according to the first to sixth inventions,
A rib is provided on an outer surface of the porous tube or the porous portion in a circumferential direction of the porous tube or the porous portion.

The piping according to the ninth invention for solving the above-mentioned problems is as follows.
In the piping according to the eighth invention,
The rib is provided obliquely with respect to the axial direction of the perforated tube or the perforated portion, and is shaped like an umbrella.
In the pipe having the above-described configuration, the condensed steam is discharged vertically downward along the rib by installing the pipe vertically.

A method for manufacturing a pipe according to a tenth aspect of the invention for solving the above problem is as follows.
In a tube formed in a cylindrical shape, a plurality of holes are formed to form a porous tube or a porous portion,
Ring-shaped ribs are divided into a plurality of parts in advance,
In the circumferential direction of the outer surface of the perforated tube or the perforated portion, attaching the ribs divided into a plurality, to form a ring-shaped rib,
A bellows or a cylindrical tube enclosing the porous tube or the porous portion is attached to the outside of the porous tube or the porous portion.

A method for manufacturing a pipe according to an eleventh invention for solving the above-described problems is as follows.
Open a plurality of holes in a flat plate to make a perforated plate,
Forming a plate-like rib parallel to one side of the porous plate perpendicular to the surface of the porous plate,
Bending the perforated plate in a direction perpendicular to the longitudinal direction of the ribs to form a cylindrical perforated tube or perforated part having ribs in the axial direction;
A bellows or a cylindrical tube enclosing the porous tube or the porous portion is attached to the outside of the porous tube or the porous portion.

A method of manufacturing a pipe according to the twelfth invention for solving the above problem is as follows.
In a tube formed in a cylindrical shape, a plurality of holes are formed to form a porous tube or a porous portion,
Insert the porous tube or the porous portion into a rib formed in a ring shape, and join the rib and the porous tube or the porous portion by shrink fitting,
A bellows or a cylindrical tube enclosing the porous tube or the porous portion is attached to the outside of the porous tube or the porous portion.

  According to the first invention, since the porous tube is provided inside the bellows to form the Helmholtz resonator, the bellows portion can be silenced and the desired frequency band can be silenced. Further, the bellows portion can absorb the pressure fluctuation of the fluid and can reduce the thermal stress due to the heat conducted to the pipe.

  According to the second aspect of the invention, since the porous tube is supported on the upstream side and the downstream side of the bellows, the rigidity of the porous tube can be improved without impairing the silencing property and the absorbability of fluid pressure fluctuation.

  According to the third invention, since the rectifying member is provided on the upstream side and the downstream side of the perforated pipe, it is possible to suppress the turbulence of the fluid upstream of the perforated pipe, and the turbulence of the fluid downstream of the perforated pipe. , Backflow can be suppressed.

  According to the fourth to sixth inventions, since the cylindrical tube is provided outside the circular tube having the porous portion, the turbulence, separation flow, and reverse flow of the fluid upstream and downstream of the porous portion are suppressed with a simple configuration. In addition, the space between the porous portion and the cylindrical tube can be silenced to mute a desired frequency band.

  According to the seventh and eighth inventions, since the rib is provided on the outer surface of the porous tube or the porous portion in the axial direction or the circumferential direction of the porous tube or the porous portion, the rigidity of the porous tube or the porous portion is improved. be able to.

  According to the ninth aspect, since the umbrella-shaped rib is provided on the outer surface of the porous tube or the porous portion obliquely in the circumferential direction of the porous tube or the porous portion, the rigidity of the porous tube or the porous portion is improved. In addition, if the pipes are installed so that the ribs are directed vertically downward, it is possible to prevent accumulation of fluid condensing on the ribs and discharge them.

  According to the tenth invention, after dividing the ring-shaped rib in advance, the rib is formed in the circumferential direction of the porous tube or the porous portion, so that welding distortion at the time of production is reduced and the periphery of the porous tube or the porous portion is reduced. Directional rigidity can be ensured.

  According to the eleventh invention, after forming the flat rib on the flat plate in advance, the flat plate is bent and the rib is set in the axial direction. The axial rigidity of the porous portion can be ensured.

  According to the twelfth invention, since the ring-shaped rib is joined to the cylindrical porous tube or the porous portion by shrink fitting, the distortion of the porous tube or the porous portion during production is reduced, and the porous tube or the porous portion is reduced. The rigidity can be ensured.

  Hereinafter, with reference to FIGS. 1-12, the piping which concerns on this invention, and its manufacturing method are demonstrated.

FIG. 1 is a schematic view showing an example of an embodiment of a pipe according to the present invention.
As shown in FIG. 1, the pipe 1 according to the present embodiment is provided with a bellows-like bellows 2 provided in a circular pipe and a bellows 2 inside the bellows 2 so as to cover the bellows 2. It has a porous tube 4 and a support member 5 (first support member) that supports the porous tube 4 on a circular tube on the upstream side (left side in FIG. 1) of the bellows 2. The layer thickness of the space between the bellows 2 and the porous tube 4 is set to a predetermined layer thickness, and the thickness of the porous tube 4 and the cross-sectional area of the hole 3 are set to predetermined values (details will be described later). 7 and 8), a Helmholtz resonator capable of silencing a desired frequency band is formed in the space between the bellows 2 and the perforated tube 4, and functions as a silencer that absorbs noise in the pipe 1 To do.

  Further, in the bellows 2 portion, the pressure fluctuation of the fluid flowing through the pipe 1 can be absorbed, and the thermal stress due to the heat conducted to the pipe 1 can be reduced. For example, the heat of the pipe 1 due to thermal expansion can be reduced. It is possible to absorb the elongation. For example, when high-temperature steam of 200 ° C. to 400 ° C. flows, the vapor is condensed from the opening portion downstream of the porous tube 4 by vertically setting the support member 5 side of the porous tube 4. It is possible to drain the liquid. The perforated tube 4 is made of, for example, carbon steel.

FIG. 2 is a schematic view showing another example of the embodiment of the piping according to the present invention.
As shown in FIG. 2, the pipe 6 of the present embodiment is a portion different from the first embodiment in that a support member 7 (second support member) is provided. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted. In the other embodiments described below, the same components are denoted by the same reference numerals, and redundant description is omitted.

  The pipe 6 of the present embodiment is provided with a support member 7 that supports the porous pipe 4 on the circular pipe on the downstream side (right side in FIG. 2) of the bellows 2 in the pipe 1 of the first embodiment. Therefore, the upstream side and the downstream side of the perforated pipe 4 arranged inside the bellows 2 are fixed to the inner wall surface of the upstream and downstream circular pipes of the bellows 2 so as to reduce noise and absorb pressure fluctuation of the fluid. The rigidity of the porous tube 4 can be improved without loss. Further, by forming the porous tube 4 from a material having a high coefficient of thermal expansion, it is possible to take into account the stress due to thermal expansion, and it is possible to absorb the thermal expansion of the pipe 6 due to thermal expansion.

FIG. 3 is a schematic view showing another example of the embodiment of the piping according to the present invention.
As shown in FIG. 3, the pipe 8 of this embodiment is different from the first and second embodiments in that instead of the support members 5 and 7, rectifying members 9 and 10 (first and second rectifying members) are provided. Part.

  The pipe 8 of this embodiment supports the porous pipe 4 on the circular pipe on the upstream side (left side in FIG. 3) of the bellows 2 instead of the support members 5 and 7 in the pipe 6 of the second embodiment. A rectifying member 9 (first rectifying member) that narrows the flow path from the inner wall surface of the circular tube to the inner wall surface of the porous tube 4 at a predetermined angle, and a circular tube downstream of the bellows 2 (right side in FIG. 3). And a rectifying member 10 (second rectifying member) that expands the flow path at a predetermined angle from the inner wall surface of the porous tube 4 to the inner wall surface of the circular tube. The rectifying members 9 and 10 may be provided independently from the support members 5 and 7 shown in FIGS. Further, in order to reduce the separation flow as much as possible downstream of the bellows 2, it is desirable to make the angle of the rectifying member 10 as gentle as possible. With the above configuration, the fluid flow is narrowed with a predetermined inclination on the upstream side of the porous tube 4 and the fluid flow is expanded with a predetermined inclination on the downstream side of the porous tube 4. It is possible to suppress turbulence of the fluid upstream of 4, and to suppress turbulence of the fluid downstream of the porous tube 4, separation flow, and backflow.

FIG. 4 is a schematic view showing another example of the embodiment of the piping according to the present invention.
As shown in FIG. 4, the pipe 11 according to this embodiment includes a circular pipe 12 having a porous portion 14 provided with a plurality of holes 13 and a cylinder attached so as to enclose the porous portion 14 outside the porous portion 14. Tube 15. Then, by setting the layer thickness of the space between the porous portion 14 and the cylindrical tube 15 to a predetermined layer thickness, the thickness of the porous portion 14 and the cross-sectional area of the hole 13 are set to predetermined values (described later). 7 and 8), a Helmholtz resonator capable of silencing a desired frequency band is formed in the space between the porous portion 14 and the cylindrical tube 15, and functions as a silencer that absorbs noise inside the pipe 11. To do. Further, in this embodiment, as compared with the configuration of the third embodiment, it is possible to suppress the turbulence, separation flow, and backflow of fluid on the upstream and downstream sides of the porous portion 14 with a simple configuration.

  In the configuration of the present embodiment, the pipe 11 itself cannot absorb the thermal elongation due to thermal expansion. Therefore, when the thermal elongation is expected, the pipe 11 having a bellows is separately connected in series. Try to absorb the elongation. Further, by forming the entire circular tube 12 or the porous portion 14 with a material having a high coefficient of thermal expansion, the stress due to the thermal expansion is taken into consideration, and further, the cylindrical tube 15 is made into a bellows. It is possible to absorb the thermal elongation of the pipe 11 due to thermal expansion.

FIG. 5 is a schematic view showing another example of the embodiment of the piping according to the present invention.
As shown in FIG. 5, the pipe 16 of the present embodiment is a part different from the fourth embodiment in that a separation wall 17 is provided.

  In the piping according to the present invention, the rigidity of the porous portion 14 is low because the thickness of the porous portion 14 cannot be increased when the silencing characteristics are taken into consideration. Therefore, in the present embodiment, by providing the separation wall 17 that separates the space in the space between the porous portion 14 and the cylindrical tube 15, the porous portion 14 is reinforced and the porous portion 14 and the cylindrical tube 15 are separated from each other. The fluid that has flowed into the space between them is made difficult to flow out on the circular tube 12 side.

FIG. 6 is a schematic view showing another example of the embodiment of the piping according to the present invention.
As shown in FIG. 6, the pipe 18 according to the present embodiment is different from the fourth and fifth embodiments in that a separation wall 20 having a communication hole 19 is provided.

  In the present embodiment, a separation wall 20 that separates the space is provided in a space between the porous portion 14 and the cylindrical tube 15, and further, a communication hole 19 that communicates the separated space is provided in the separation wall 20. The sound absorption characteristics of the Helmholtz resonator formed in the space between the porous portion 14 and the cylindrical tube 15 can be freely set so that a desired frequency band can be silenced.

  Here, the Helmholtz resonator will be described with reference to the mathematical formula of the Helmholtz resonator shown in FIG.

  In the pipes of Examples 1 to 6, the thickness of the porous tube 4 or the porous portion 14, the number (density) of the holes 3 and 13, the diameter (cross-sectional area) of the holes 3 and 13, the porous tube 4 or the porous portion 14 are By appropriately setting the thickness or the like of the back layer to be formed (the layer between the porous tube 4 and the bellows 2 or the layer between the porous portion 14 and the outer wall 15), it can silence the desired frequency band. In particular, the sound absorption performance at a high frequency (500 Hz to 2000 Hz) is improved.

  Here, referring to the principle diagram of the Helmholtz resonator, the portion of the volume V provided in the middle of the pipe can be regarded as a space forming the Helmholtz resonator, and can be represented by a simple configuration as shown in FIG. The thickness of the back layer of the porous tube 4 or the porous portion 14 is La, the plate thickness of the porous tube 4 or the porous portion 14 is Lb, the cross-sectional area of the holes 3 and 13 is Sb, the sound velocity is c, and the cross-sectional area of the pipe is When S is used, a desired sound absorbing performance (silence) can be obtained by using the following basic formula of the Helmholtz resonator.

  Specifically, as shown in FIGS. 8A and 8B, increasing the thickness La of the back layer of the porous tube 4 or the porous portion 14 increases the sound absorption coefficient. As the thickness Lb is smaller, a higher sound absorption coefficient can be obtained in a wider frequency band.

FIG. 9 is a schematic view showing another example of the embodiment of the piping according to the present invention.
In the piping according to the present invention, as described above, when the silencing characteristics are taken into consideration, the thickness of the porous tube 4 (or the porous portion 14) cannot be increased, and therefore the rigidity of the porous tube 4 (or the porous portion 14) is low. In this embodiment, as shown in FIG. 9, by providing a plurality of ribs 21 as reinforcing members in the circumferential direction on the outer surface of the porous tube 4 (or the porous portion 14), the porous tube 4 (or the porous portion 14). ) The circumferential rigidity of itself can be reinforced.

  When manufacturing the rib 21 in the circumferential direction, as shown in FIG. 12, a plurality of holes 3 (or holes 13) are provided in a cylindrical tube to form a porous tube 4 (or a porous portion 14). The rib 21 having a shape is divided into a plurality of divided ribs 21a in advance, and the divided ribs 21a divided into a plurality are welded and attached to the circumferential direction of the outer surface of the porous tube 4 (or the porous portion 14). Thus, the porous tube 4 (or the porous portion 14) having a plurality of ring-shaped ribs 21 in the circumferential direction is obtained. Thereafter, the bellows 2 or the cylindrical tube 15 is attached outside the porous tube 4 (or the porous portion 14) so as to enclose the porous tube 4 (or the porous portion 14), thereby constituting a pipe. By the above manufacturing method, welding distortion when the rib 21 is attached can be reduced. Note that any number of ribs 21 may be divided.

  As another method for producing the circumferential rib 21, a plurality of holes 3 (or holes 13) are provided in a cylindrical tube to form a porous tube 4 (or a porous portion 14). The porous tube 4 (or the porous portion 14) is inserted into the formed rib 21, and the rib 21 and the porous tube 4 (or the porous portion 14) are joined together by shrink fitting to form a ring shape in the circumferential direction. The porous tube 4 (or the porous portion 14) having a plurality of ribs 21 is used. Thereafter, the bellows 2 or the cylindrical tube 15 is attached outside the porous tube 4 (or the porous portion 14) so as to enclose the porous tube 4 (or the porous portion 14), thereby constituting a pipe. By the above manufacturing method, distortion at the time of attaching the rib 21 can be reduced.

FIG. 10 is a schematic view showing another example of the embodiment of the piping according to the present invention.
As shown in FIG. 10, the present embodiment is different from the seventh embodiment in that an axial rib 22 is provided instead of the circumferential rib 21.

  In this embodiment, as shown in FIG. 10, a plurality of ribs 22 serving as reinforcing members are provided in the axial direction on the outer surface of the porous tube 4 (or the porous portion 14). Alternatively, the axial rigidity of the porous portion 14) itself can be reinforced.

  When the rib 22 in the axial direction is produced, a plurality of holes 3 (or holes 13) are formed in a flat plate to form a porous plate, and a plate-like rib 22 perpendicular to the surface of the porous plate and parallel to one side of the porous plate is formed. Form. Then, the perforated plate is bent in a direction perpendicular to the longitudinal direction of the ribs 22 to form a cylindrical perforated tube 4 (or perforated portion 14) having a plurality of ribs 22 in the axial direction. Thereafter, the bellows 2 or the cylindrical tube 15 is attached outside the porous tube 4 (or the porous portion 14) so as to enclose the porous tube 4 (or the porous portion 14), thereby constituting a pipe. By the above manufacturing method, it is possible to reduce welding distortion when the rib 22 is attached.

FIG. 11 is a schematic view showing another example of the embodiment of the piping according to the present invention.
As shown in FIG. 11, the present embodiment is different from the seventh embodiment in that a rib 23 having an umbrella shape in the circumferential direction is provided instead of the circumferential rib 21.

  In the present embodiment, as shown in FIG. 11, a plurality of ribs 23 serving as reinforcing members are provided in the circumferential direction on the outer surface of the porous tube 4 (or the porous portion 14). 4 (or the porous portion 14) is provided obliquely with a predetermined angle with respect to the axial direction. For example, it is formed in an umbrella shape. With the above configuration, the rigidity of the porous tube 4 (or the porous portion 14) itself can be reinforced as in the seventh embodiment. Further, if the pipe having the above-described configuration is installed in the vertical direction and the umbrella-shaped rib 23 is installed in a vertically obliquely downward direction with respect to the wall surface of the porous tube 4 (or the porous portion 14), that is, the end of the rib 23 spreads. If the portion is disposed on the vertically lower side, when a fluid such as steam is condensed, the condensed fluid is discharged vertically downward along the rib 23, and retention of the condensed fluid in the rib 23 can be prevented.

  The pipe according to the present invention is applicable not only to the exhaust pipe of a combustion engine but also to pipes of various devices, and is particularly suitable as a steam pipe of a steam turbine through which a high-temperature fluid such as steam flows.

It is the schematic which shows an example (Example 1) of embodiment of piping which concerns on this invention. It is the schematic which shows another example (Example 2) of embodiment of piping which concerns on this invention. It is the schematic which shows another example (Example 3) of embodiment of piping which concerns on this invention. It is the schematic which shows another example (Example 4) of embodiment of piping which concerns on this invention. It is the schematic which shows another example (Example 5) of embodiment of piping which concerns on this invention. It is the schematic which shows another example (Example 6) of embodiment of piping which concerns on this invention. It is a figure explaining the Helmholtz resonator in this invention. It is a figure which shows the frequency characteristic of a sound absorption factor at the time of changing a back layer thickness and a porous tube thickness in the Helmholtz resonator in this invention. It is the schematic which shows another example (Example 7) of embodiment of piping which concerns on this invention. It is the schematic which shows another example (Example 8) of embodiment of piping which concerns on this invention. It is the schematic which shows another example (Example 9) of embodiment of piping which concerns on this invention. It is a figure explaining an example (Example 7) of embodiment of the manufacturing method of piping which concerns on this invention.

Explanation of symbols

1, 6, 8, 11, 16, 18 Piping 2 Bellows 3 Hole 4 Porous tube 5 Support member 7 Support member 9 Rectifying member 10 Rectifying member 12 Circular tube 13 Hole 14 Porous portion 15 Cylindrical tube 17 Separation wall 19 Communication hole 20 Separation Wall 21, 22, 23 rib

Claims (12)

A bellows-shaped bellows provided in the circular tube, a porous tube disposed inside the bellows so as to cover the bellows, and a plurality of holes, and the porous tube as a circular tube on the upstream side of the bellows A first support member to support,
The layer thickness of the space between the bellows and the porous tube is a predetermined layer thickness, the thickness of the porous tube is a predetermined thickness, and the space is a Helmholtz resonator that silences a desired frequency band. Characteristic piping. In the piping according to claim 1,
The porous tube is formed of a material having a high coefficient of thermal expansion,
A pipe having a second support member for supporting the porous pipe on a circular pipe on the downstream side of the bellows. The piping according to claim 2,
A bellows-shaped bellows provided in the circular tube, a porous tube disposed inside the bellows so as to cover the bellows, and a plurality of holes, and the porous tube as a circular tube upstream of the bellows A first rectifying member that supports and narrows a flow path at a predetermined angle from an inner wall surface of the circular tube to an inner wall surface of the porous tube; and the porous tube is supported by a circular tube on the downstream side of the bellows; A second rectifying member that expands the flow path at a predetermined angle from the inner wall surface to the inner wall surface of the circular pipe,
The layer thickness of the space between the bellows and the porous tube is a predetermined layer thickness, the thickness of the porous tube is a predetermined thickness, and the space is a Helmholtz resonator that silences a desired frequency band. Characteristic piping. A circular tube having a porous portion provided with a plurality of holes, and a cylindrical tube attached so as to enclose the porous portion outside the porous portion;
The layer thickness of the space between the porous part and the cylindrical tube is a predetermined layer thickness, the thickness of the porous part is a predetermined thickness, and the space is a Helmholtz resonator that silences a desired frequency band Piping characterized by The piping according to claim 4,
A pipe having a separation wall for separating the space in a space between the porous portion and the cylindrical tube. In the piping according to claim 5,
A pipe characterized in that a plurality of communication holes are provided in the separation wall. In the piping according to any one of claims 1 to 6,
A pipe characterized in that a rib is provided on the outer surface of the porous tube or the porous portion in the axial direction of the porous tube or the porous portion. In the piping according to any one of claims 1 to 6,
A pipe characterized in that a rib is provided on the outer surface of the porous tube or the porous portion in the circumferential direction of the porous tube or the porous portion. The piping according to claim 8,
A pipe characterized in that the rib is provided obliquely with respect to the axial direction of the perforated pipe or the perforated portion, and has an umbrella shape. In a tube formed in a cylindrical shape, a plurality of holes are formed to form a porous tube or a porous portion,
Ring-shaped ribs are divided into a plurality of parts in advance,
In the circumferential direction of the outer surface of the perforated tube or the perforated portion, attaching the ribs divided into a plurality, to form a ring-shaped rib,
A method for manufacturing a pipe, wherein a bellows or a cylindrical tube containing the porous tube or the porous portion is attached outside the porous tube or the porous portion. Open a plurality of holes in a flat plate to make a perforated plate,
Forming a plate-like rib parallel to one side of the porous plate perpendicular to the surface of the porous plate,
Bending the perforated plate in a direction perpendicular to the longitudinal direction of the ribs to form a cylindrical perforated tube or perforated part having ribs in the axial direction;
A method for manufacturing a pipe, wherein a bellows or a cylindrical tube containing the porous tube or the porous portion is attached outside the porous tube or the porous portion. In a tube formed in a cylindrical shape, a plurality of holes are formed to form a porous tube or a porous portion,
Insert the porous tube or the porous portion into a rib formed in a ring shape, and join the rib and the porous tube or the porous portion by shrink fitting,
A method for manufacturing a pipe, wherein a bellows or a cylindrical tube containing the porous tube or the porous portion is attached outside the porous tube or the porous portion.

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