EP3688358A1

EP3688358A1 - Tube for air distribution systems

Info

Publication number: EP3688358A1
Application number: EP18786404.6A
Authority: EP
Inventors: Ruedi Kriesi
Original assignee: Zehnder Group International AG
Current assignee: Zehnder Group International AG
Priority date: 2017-09-25
Filing date: 2018-09-25
Publication date: 2020-08-05
Also published as: EA202090840A1; WO2020095086A1

Abstract

The invention relates to a tube (1), in particular for an air distribution system in buildings or parts thereof, comprising an inner wall (2), an outer wall (4) surrounding the inner wall and an intermediate space (3) between the inner wall (2) and the outer wall (4). The intermediate space (3) is filled at least in partial regions with a sound-absorbing material (5).

Description

Pipe for air distribution systems

The invention relates to a pipe, in particular for an air distribution system in buildings or parts thereof, with an inner wall, an outer wall surrounding the inner wall and a space between the inner wall and the outer wall.

Such pipes are known. The intermediate space is used in particular for heat and sound insulation. The inner wall of the tube and the outer wall of the tube touch one another at selected locations which are spaced apart from one another along the axial direction and / or along the circumferential direction of the tube.

Such a pipe is e.g. known from EP1724508A1.

The invention has for its object in a tube of the beginning

described design to improve the sound insulation, in particular by the damping of radially propagating from the inside of the tube to the outside sound waves and the attenuation of axially propagating axially inside the pipe wall along the pipe amplifying sound waves.

This object is achieved by means of a tube, in particular for a

Air distribution system in buildings or parts thereof, with an inner wall, an outer wall surrounding the inner wall and a space between the inner wall and the outer wall, the space according to the invention being filled at least in partial areas with a sound-absorbing material.

The filling of sound-absorbing material reduces the propagation of sound (“structure-borne sound”) in the axial direction, ie along the longitudinal direction of the pipe, and in the radial direction, ie across the longitudinal direction of the pipe. The sound-absorbing material preferably fills the entire space. This achieves maximum sound absorption along the axial and radial directions.

In cases where the sound absorption along the axial direction is more important than along the radial direction, it is sufficient if the sound-absorbing material fills the intermediate space in axial partial areas of the tube. This also results in mechanical, in particular elastic, properties of the

Tube, which are different along the axial direction. Filling the space with the sound absorbing material and / or

Sound-absorbing properties of the material can be variable, in particular periodically, along the axial direction. In particular, areas with and without sound-absorbing material can alternate along the axial direction.

The outer wall is preferably designed as a corrugated tube with wave crests and wave troughs extending along the circumferential direction. This will make it easier to bend the pipe.

The inner wall is preferably designed as a corrugated tube with wave crests and wave troughs extending along the circumferential direction. This will make it easier to bend the pipe.

In a particularly preferred embodiment, the sound-absorbing material has a foam material. This results in a strong sound absorption in the axial and radial directions with a low pipe weight.

The outer wall preferably contains a polymer material.

The inner wall preferably contains a polymer material.

The foam material can have a polymer, in particular an elastomer. The use of an elastomer foam ensures that the pipe can be bent easily.

The tube can extend from the inner wall to the one in the intermediate space

Have spacer extending outer wall. This ensures that the wall thickness of the pipe due to mechanical influence on the pipe, such as in Bending the tube or when applying a local compressive force in the radial direction does not become too small.

The spacer preferably has a higher rigidity in the radial direction of the tube than in the axial direction of the tube. This ensures that the pipe can be bent with a relatively small amount of force (pair of forces), while a large amount of force is required to squeeze the pipe, i.e. reduce its cross-sectional area.

According to a first particularly preferred embodiment, the spacer is designed as a corrugated tube with wave crests and wave troughs extending along the circumferential direction. This reduces the effort required when bending the tube, since the corrugated tube can be stretched on the outside of the bend with relatively little axial tensile force and can be compressed on the inside of the bend with relatively little axial compressive force.

With the corrugated pipe, crests and troughs of the inner wall,

Wave crests and wave troughs of the outer wall as well as wave crests and wave troughs of the spacer are located at the same locations along the axial direction of the tube. The corrugations W2 of the inner wall, W4 of the outer wall and W6 of the spacer are therefore in phase.

The corrugation W2 of the inner wall and the corrugation W4 of the outer wall preferably each have a smaller amplitude A2 or A4 than the amplitude A6 of the corrugation W6 of the spacer, that is to say A2 <A6 and A4 <A6. This will make the

Flow resistance for an air flow inside the tube kept low.

The inner wall and the outer wall preferably each have a smaller wall thickness D2 or D4 than the wall thickness D6 of the spacer, ie D2 <D6 and D4 <D6. This contributes to the easier bendability of the pipe.

In a special embodiment, the corrugation W2 of the inner wall, the corrugation W4 of the outer wall and the corrugation W6 of the spacer in the axial direction of the tube can all have the same wavelength L, that is to say L2 = L4 = L6 = L.

Alternatively, the corrugation W2 of the inner wall and / or the corrugation W4 of the outer wall can have a smaller wavelength L2 or L4 than the wavelength L6 of the Corrugation W6 of the spacer in the axial direction of the tube, i.e. L2 <L6 and L4 <L6.

The wavelength L6 of the corrugation W6 of the spacer is preferably a multiple of the wavelength L2 of the corrugation W2 of the inner wall 2, that is to say L6 = n x L2, n = 1, 2, 3, 4,, 20 in particular.

The wavelength L6 of the corrugation W6 of the spacer is preferably a multiple of the wavelength L4 of the corrugation W4 of the outer wall, that is to say L6 = n x L4, where n = 1, 2, 3, 4,... 20 applies in particular.

The spacer can have a wall thickness D6 of 0.2 mm to 3 mm and

preferably have from 0.5 mm to 1.5 mm.

The spaces between the inner wall, the outer wall and the spacer are preferably foamed with the sound-absorbing material, in particular with melamine resin. This has advantages in terms of production technology, because foaming can be carried out in known processes (for the production of pipes without

sound absorbing material) can be easily integrated.

The spacer is preferably designed as a helical (helical) web which extends coaxially to the inner wall and to the outer wall along the axial direction in the intermediate space. This also has manufacturing advantages.

On the one hand, wave crests of the inner wall and wave valleys of the

Outer wall are located at the same locations along the axial direction of the tube, and on the other hand troughs of the inner wall and wave crests of the outer wall are located at the same locations along the axial direction of the tube. The corrugations W2 of the inner wall and the corrugations W4 of the outer wall are therefore in phase opposition. This helps ease the effort of bending the tube.

On the one hand, wave crests of the inner wall and wave valleys of the

Outer wall protrude into the space between the helical web and, on the other hand, wave troughs of the inner wall extend along a radially inner side of the helical web and wave crests of the outer wall extend along a radially outer side of the helical web. Preferably, the radially inner side and the radially outer side of the

helical ridges each convex and protrude into the troughs of the inner wall or into the wave crests of the outer wall.

The spacer can have a thickness of 0.2 mm to 5 mm and preferably 1 mm to 3 mm.

The spacer preferably contains a polymer material.

The spacer can also have mineral fibers and / or metal fibers.

This can improve mechanical strength and fire resistance.

The space between the one formed as a corrugated tube is preferably

Outer wall and the inner wall are foamed with a foam material which has a course W3 which fluctuates periodically along the axial direction

Has foam material wall thickness D3. This contributes to the easier bendability of the pipe.

Preferably, the foam material with the radially inner surface of the

External wall bonded, in particular glued and / or

welded.

The foam material is preferably integrally connected to the radially outer surface of the inner wall, in particular glued and / or welded.

The foam material preferably has a periodically fluctuating course W3 ^{* of} the foam material flute (modulus of elasticity) along the axial direction. This contributes to the easier bendability of the pipe.

The courses W3 and W3 ^{* can be in} phase, ie maxima W3 ^* a and minima W3 ^* b of the course W3 ^{* of} the foam material flute Fl and maxima W3a and Minima W3b of the course W3 of the foam material wall thickness D3 are in the same places along the axial direction of the tube.

Alternatively, the curves W3 and W3 ^{* can be in} phase opposition, ie that the minimums W3 ^* b and the maximums W3 ^* a of the curve W3 ^{* of} the foam material flute Fl and Maxima W3a and minimums W3b of the curve W3 of the foam material wall thickness D3 are in the same locations along the axial direction of the tube. The periodically fluctuating course W3 ^{* of} the foam material hardness and / or the periodically fluctuating course W3 of the foam material wall thickness D3 can have a smaller wavelength L3 ^* or L3 than the wavelength L4 of the corrugation W4 of the outer wall, i.e. L3 ^* <L4 or L3 <L4.

The wavelength L4 of the corrugation W4 of the outer wall can be a multiple of the wavelength L3 of the corrugation W3 of the periodically fluctuating course of the foam material wall thickness D3, i.e. L4 = n x L3, where in particular n = 1, 2, 3, 4, ..., 10 applies.

The wavelength L4 of the corrugation W4 of the outer wall can be a multiple of the wavelength L3 ^{* of} the corrugation W3 ^{* of} the periodically fluctuating course of the foam material hardness, ie L4 = nx L3 ^* , in particular n = 1, 2, 3, 4, .. ., 10 applies.

The course W3 of the foam material wall thickness D3, which fluctuates periodically along the axial direction, is preferably determined by the corrugation W4 of the outer wall. This is simple in terms of manufacturing technology.

The course W3 of the foam material wall thickness D3, which fluctuates periodically along the axial direction, is preferably determined by a corrugation W2 of the inner wall. This is simple in terms of manufacturing technology.

The corrugation W4 of the outer wall and the corrugation W2 of the inner wall can be in phase.

The corrugation W4 of the outer wall and the corrugation W2 of the inner wall can be in phase opposition.

The wavelength L4 of the corrugation W4 of the outer wall can be a multiple of the wavelength L2 of the corrugation W2 of the inner wall, i.e. L4 = n x L2, where in particular n = 1, 2, 3, 4, ..., 10 applies.

In a special embodiment, the course W3 of the foam material wall thickness D3, which fluctuates periodically along the axial direction, is only determined by the corrugation W4 of the outer wall, i.e. the inner wall is straight,

uncurved pipe no curl. According to a second, particularly preferred embodiment, the inner wall and / or the outer wall is connected to a helical reinforcement which extends coaxially to the inner wall and to the outer wall along the axial direction of the tube. This reduces the effort required when bending the tube, since the corrugated tube can be stretched on the outside of the bend with relatively little axial tensile force and can be compressed on the inside of the bend with relatively little axial compressive force.

The helical reinforcement is preferably embedded in the outer wall.

The helical reinforcement is preferably integrally connected to the radially inner surface of the outer wall and to the foam material.

especially welded and / or glued.

The helical reinforcement is preferably with the radially outer one

Surface of the inner wall and cohesively connected to the foam material, in particular welded and / or glued.

The helical reinforcement can be a helically wound strand. This is simple in terms of manufacturing technology.

The strand can have a rectangular cross-section, the long side LS of the rectangle being aligned parallel to the longitudinal direction of the tube, and in particular the length ratio of the long side LS to the short side KS of the rectangle being in the range from 1: 1 to 10: 1 1 <LS / KS <10. This contributes to the stability and radial compactness of the pipe.

The strand can have an oval cross-section, the long diagonal LD of the oval being aligned parallel to the longitudinal direction of the tube, and in particular the length ratio of the long diagonal LD to the short diagonal KD of the oval being in the range from 1: 1 to 10: 1 1 <LD / KD <10. This contributes to the stability and radial compactness of the tube.

The reinforcement can have polymer material and / or metal.

The reinforcement can also have mineral fibers and / or metal fibers.

This can improve mechanical strength and fire resistance. The wall thickness D4 of the outer wall of the tube is preferably greater than the wall thickness D2 of the inner wall of the tube, ie D4> D2.

The inner wall preferably has a wall thickness D2 of 0.05 mm to 0.3 mm and the outer wall has a wall thickness D4 of 0.2 mm to 1.2 mm. That contributes to

Robustness of the pipe.

The inner wall preferably has one on its radially inner surface

Coating containing aluminum. On the one hand, this contributes to the hygiene of the pipe and, on the other hand, enables the inner surface of the pipe to be grounded in order to avoid local electrostatic charging.

The tube expediently has a circular cross section or a rectangular cross section. It can also have a polygonal cross section, in particular a hexagonal cross section.

Further advantages, features and possible uses of the invention result from the following description of non-restrictive embodiments, wherein

1 shows a longitudinal section through the tube wall of a first embodiment of the tube according to the invention;

2 shows a longitudinal section through the tube wall of a second embodiment of the tube according to the invention;

Fig. 3 is a side view, a longitudinal section, a cross section and a

Perspective view of a third embodiment of the tube according to the invention shows;

Fig. 4 shows a longitudinal section through the tube wall of the third embodiment of the tube according to the invention in a straight, i.e. shows not bent state of the tube;

5 shows a longitudinal section through the tube wall of the third embodiment of the tube according to the invention in the curved state of the tube; 6 shows a side view, a longitudinal section, a cross section and a perspective view of a fourth embodiment of the tube according to the invention;

Fig. 7 is a longitudinal section of a fifth embodiment of the pipe according to the invention in a straight, i.e. shows not bent state of the tube;

8 shows a longitudinal section through the tube wall of the fifth embodiment of the tube according to the invention in the curved state of the tube;

9 shows a longitudinal section through the tube wall of a sixth embodiment of the tube according to the invention;

Fig. 10 shows a first course of two pipe parameters as a function of the axial

Shows coordinate along the axial direction of the pipe according to the invention; and

Fig. 1 1 shows a second course of two pipe parameters as a function of the axial

Coordinate along the axial direction of the pipe according to the invention shows.

1 shows a longitudinal section through the tube wall of a first embodiment of a tube 1 according to the invention. The tube 1 has an inner wall 2, an outer wall 4 surrounding the inner wall and an intermediate space 3 between the inner wall 2 and the outer wall 4. The intermediate space 3 is filled with a sound-absorbing material 5. The tube 1 contains in the intermediate space 3 a spacer 6 in the form of a corrugated tube which extends from the inner wall 2 to the outer wall 4. The spacer 6 has a corrugation W6 with a wavelength L6. The outer wall 4 and the inner wall 2 have a corrugation W4 or W2 with a wavelength L4 or L2. In this embodiment of the tube 1, all the corrugations W2, W4 and W6 have the same wavelength L2 = L4 = L6 = L. The three corrugations W2, W4 and W6 run in phase here, ie the crests 2a of the inner wall 2, the crests 4a of the outer wall 4 and the wave crests 6a of the spacer 6 are at the same axial positions along the axial direction of the tube 1, while the wave troughs 2b of the inner wall 2, the wave troughs 4b of the outer wall 4 and the wave troughs 6b of the spacer 6 are at the same axial positions along the axial direction of the Tube 1 are located. The spacer 6 has a higher rigidity in the radial direction of the tube 1 than in the axial direction of the tube 1. This ensures that the pipe 1 can be bent with a relatively small amount of force (pair of forces), while a large amount of force is required to squeeze the pipe 1, ie to reduce its cross-sectional area.

2 shows a longitudinal section through the tube wall of a second embodiment of the tube 1 'according to the invention. The pipe 1 ’also has one

Inner wall 2, an outer wall 4 surrounding the inner wall and one

Gap 3 between the inner wall 2 and the outer wall 4. The

Intermediate space 3 is also filled with a sound-absorbing material 5. The tube 1 'contains in the intermediate space 3 a spacer 7 extending from the inner wall 2 to the outer wall 4, but here in the form of a

helical or helical web 7. The spacer 7 has a pitch G. The outer wall 4 and the inner wall 2 have a corrugation W4 or W2 with a wavelength L4 or L2. In this embodiment of the tube 1 ', the two corrugations W2 and W4 have the same wavelength L2 = L4 = L, which in turn is the same size as the pitch G of the spacer, i.e. L2 = G. The two corrugations W2 and W4 run in opposite phase here, i.e. the wave crests 2a of the inner wall 2 and the wave troughs 4b of the outer wall 4 are at the same axial positions along the axial direction of the tube 1 ', while the wave troughs 2b of the inner wall 2 and the wave crests 4a of the outer wall 4 are at the same axial positions along the axial direction of the pipe 1' Rohres 1 'are. The spacer 7 also has a higher rigidity in the radial direction of the pipe 1 ″ than in the axial direction of the pipe 1 ’. This in turn ensures that the pipe 1 ’can be bent with a relatively small amount of force (pair of forces), while a large amount of force is required to squeeze the pipe 1’, i.e. reduce its cross-sectional area.

In Fig. 3 are a side view, a longitudinal section, a cross section and a

Perspective view of a third embodiment of the tube 1 ”according to the invention is shown. The tube 1 has an inner wall 2, one surrounding the inner wall

Outer wall 4 and an intermediate space 3 between the inner wall 2 and the outer wall 4. The intermediate space 3 is sound-absorbing

Foam material 5 filled.

4 is a longitudinal section through the tube wall of the third embodiment of the tube 1 ”according to the invention in a straight, ie not curved, state of the tube 1 ”shown. The outer wall 4 is designed as a corrugated tube 4a, 4b with wave crests 4a and wave troughs 4 extending along the circumferential direction. In contrast to the outer wall 4, the inner wall 2 in the straight state of the tube 1 ”has no corrugation, that is to say neither wave crests nor troughs, or only a slight corrugation in comparison to the corrugation of the outer wall 4, the wave amplitudes of which are less than 1/10 of the wave amplitudes of the corrugation the outer wall 4. The thickness D3, measured in the radial direction, of the intermediate space 3 filled with the sound-absorbing material 5 is periodic due to the corrugated tube 4a, 4b

swaying. In the areas 9 where the thickness D3 of the intermediate space 3 or the sound-insulating foam material 5 has its minimum values, the hardness H or the modulus of elasticity of the foam material 5 can also be their minimum or their

have maximum values. In this context, hardness H or modulus of elasticity means the measurable hardness or modulus of elasticity of the solid-air mixture. The hardness H or the modulus of elasticity of the foam material 5 can be determined by

Changing the total air content, the size of the air bubbles, the air wall thickness and the choice of the solid material. In addition to the mentioned in-phase (see also FIG. 10) or antiphase (see also FIG. 11) between the course W3 of the thickness D3 and the course W3 ^{* of} the hardness H (modulus of elasticity), other phase relationships (between 0 and 180 °) can be selected between the course W3 and the course W3 ^* . The inner wall 2 is integrally connected to the foam material 5, that is to say glued and / or welded. As a result, the inner skin 2 follows any deformations,

in particular also the radial deformations, the surface of the

Foam material 5. When the pipe is bent 1 ”, the pipe wall is subject to compression on the inside of the pipe bend.

In an alternative embodiment (not shown), the inner wall or

Inner skin 2 a curl. The corrugation of the inner wall or inner skin 2 has a smaller wave amplitude than the corrugation of the outer wall 4. The wave amplitude of the corrugation of the inner wall or inner skin 2 is preferably less than 1/5 of the wave amplitude of the corrugation of the outer wall 4.

5 shows a longitudinal section through the tube wall of the third embodiment of the tube 1 ”according to the invention in the curved state of the tube 1”. You can see the compressed or compressed due to the pipe bend Pipe wall. Since the inner wall or inner skin 2 is very thin and is made of a material with high hardness or high modulus of elasticity, it is hardly stretchable along the axial direction of the tube 1 ”, but it is very flexible. On the one hand, this leads to the fact that on the inside of the pipe bend the in the

The arc length of the inner wall 2 of the curved tube 1 ”measured in the axial direction is shorter than the corresponding length of the measured in the axial direction

Inner wall 2 in the straight state of the tube 1 ”. On the other hand, this means that the one measured in the axial direction on the outside of the pipe bend

Arc length of the outer wall 2 of the curved pipe 1 "is practically the same length as the corresponding length of the inner wall 2 measured in the axial direction in the straight state of the pipe 1". In other words, the inner wall or inner skin 2 on the outside of the pipe bend behaves as the neutral fiber of the bent pipe 1 ”. The arc length of the central bending line M inside the pipe bend is therefore shorter than the corresponding length of the central line in the straight state of the pipe 1 ”. Due to the bond between the

Inner wall or inner skin 2 and the foam material 5 and because of the high flexibility of the inner wall 2, this can follow any deformation of the foam material 5. The periodic course W3 of the thickness D3 and the periodic course W3 ^{* of} the hardness H or the modulus of elasticity of the foam material 5 contribute to the fact that the inner wall 2 is predominantly in the areas 9 of minimal thickness D3

Foam material 5 radially outwards, i.e. folds into the foam material 5 as shown by the folds 10 in FIG. 5.

In the alternative version (not shown) the third version with

Inner wall corrugation, the inner wall can be both lengthened and shortened along the axial direction of the tube. Now the inner wall 2 on the outside of the pipe bend does not behave as the neutral fiber of the bent pipe 1 ”. Rather, the arc length of the central or approximately central bending line M inside the pipe bend is now as long as that

Corresponding length of the center line in the straight state of the tube 1. That is, the center bending line or the bending surface M intersecting the drawing plane is the imaginary, non-material “neutral fiber” or “neutral surface” inside the tube 1. The two cutting lines of this immaterial neutral bending surface M with the tube wall represent material, i.e. material neutral fibers in mutually opposite areas of the curved tube wall. In Fig. 6 are a side view, a longitudinal section, a cross section and a

Perspective view of a fourth embodiment of the tube 1 ^* according to the invention is shown. The tube 1 ^* has an inner wall 2, one surrounding the inner wall

Foam material 5 filled. In addition, the inner wall 2 of the tube 1 ^{* is} connected to a helical or helical reinforcement T which extends coaxially to the inner wall 2 and to the outer wall 4 along the axial direction of the tube 1 ^* . The helical reinforcement T is integrally connected to the radially outer surface of the inner wall 2 and with the foam material 5, that is to say welded and / or glued. The helical reinforcement T contributes to the dimensional stability of the pipe 1 ^* . Similar to the spacer 6 mentioned above in the second embodiment, the reinforcement T has a higher rigidity in the radial direction of the tube 1 ^* than in the axial direction of the tube 1 ^* . This ensures that the tube 1 ^* with a relatively small effort

(Pair of forces) can bend, while a high effort is required to squeeze the pipe 1 ^* , ie to reduce its cross-sectional area.

FIG. 7 shows a longitudinal section of a fifth embodiment of the pipe 1 ^** according to the invention in the straight, ie non-curved state of the pipe 1 ^** .

The pipe 1 ^** has an inner wall 2, an outer wall 4 surrounding the inner wall and an intermediate space 3 between the inner wall 2 and the outer wall 4. The intermediate space 3 is filled with a sound-absorbing foam material 5.

In addition, the outer wall 4 of the pipe 1 ^{** is} connected to a helical or helical reinforcement T which extends coaxially to the inner wall 2 and to the outer wall 4 along the axial direction of the pipe 1 ^** . The helical reinforcement T is a helically wound strand 7 'which is embedded in the outer wall 4. Between the helically wound strand T, the outer wall 4 has a helical crest 4a. in the

In contrast to the outer wall 4, the inner wall 2 in the straight state of the pipe 1 ^{** has} no corrugation, that is to say neither wave crests nor troughs. Similar to the reinforcement T mentioned above in the fourth embodiment, the reinforcement T has a higher rigidity in the radial direction of the tube 1 ^* than in the axial direction of the tube 1 ^* . This ensures that the pipe 1 ^{** can be bent} with a relatively small amount of force (pair of forces) while it is high effort required to squeeze the pipe 1 ^** , ie to reduce its cross-sectional area.

In an alternative embodiment (not shown) of the fifth embodiment, the inner wall 2 has a corrugation.

8 shows a longitudinal section through the tube wall of the fifth embodiment of the tube 1 ^** according to the invention in the curved state of the tube 1 ^** . Similar to FIG. 5, the tube wall compressed or compressed due to the tube curvature can be seen on the inside of the tube curve. Since the inner wall 2 is very thin and is made of a material with great hardness or high modulus of elasticity, the inner wall 2 is hardly stretchable along the axial direction of the tube 1 ^** , but it is very flexible. Similar to the third embodiment in FIG. 5, this leads to the fact that on the inside of the pipe curvature the arc length of the inner wall 2 of the curved pipe 1 ^** measured in the axial direction is shorter than the corresponding length of the inner wall 2 measured in the axial direction in a straight line Condition of the pipe 1 ^** .

On the other hand, this means that on the outside of the pipe curvature the arc length of the outer wall 2 of the curved pipe 1 ^** measured in the axial direction is practically the same length as the corresponding length of the inner wall 2 measured in the axial direction in the straight state of the pipe 1 ^** . In other words, the inner wall 2 on the outside of the pipe bend behaves as the neutral fiber or neutral surface of the bent pipe 1 ^** . The arc length of the central bending line or bending surface M in the interior of the pipe bend is therefore shorter than the corresponding length of the central line in the straight state of the pipe 1 ”(FIG. 7). Due to the material bond between the inner wall 2 and the foam material 5 and because of the high flexibility of the inner wall 2, this can follow any deformation of the foam material 5. The periodic course W3 of the thickness D3 and the periodic course W3 ^{* of} the hardness H or the modulus of elasticity of the foam material 5 contribute to the fact that the inner wall 2 predominantly radially outwards in the regions 9 of minimal thickness D3 of the foam material 5, ie in the

Foam material 5 folds in as shown by folds 10 in FIG. 8.

In the alternative version (not shown) with the fifth version

Inner wall corrugation, the inner wall can be both lengthened and shortened along the axial direction of the tube. Now the inner wall 2 behaves the outside of the pipe bend not as the neutral fiber or neutral surface of the bent pipe 1 ”. Rather, the arc length of the central bending line or bending surface M inside the pipe bend is just as long as the corresponding length of the central line or surface in the straight state of the pipe 1. That is, the central bending line or bending surface M is the imaginary, non-material "Neutral fiber" or "neutral surface".

In Fig. 9 is a longitudinal section through the tube wall of a sixth

Embodiment of the pipe 1 ’” according to the invention. The pipe 1 ″ ”has an inner wall 2, an outer wall 4 surrounding the inner wall and one

Gap 3 between the inner wall 2 and the outer wall 4. The

Gap 3 is filled with a sound absorbing material 5. The

Outer wall 4 is a corrugated tube 4a, 4b with wave crests 4a and wave troughs 4b extending along the circumferential direction. Likewise, the inner wall 2 is a corrugated tube 2a, 2b which extends along the circumferential direction

Wave crests 2a and wave troughs 2b. The spacer 6 is also a corrugated tube 6a, 6b with wave crests 6a and 6 extending along the circumferential direction

Wave valleys 6b. The corrugation W2 of the inner wall 2 and the corrugation W4

Outer wall 4 each have a smaller amplitude A2 or A4 than the amplitude A6 of the corrugation W6 of the spacer 6. The wavelength L6 of the corrugation W6 of the spacer 6 is a multiple of the wavelength L2 of the corrugation W2

Inner wall 2. The wavelength L6 of the corrugation W6 of the spacer 6 is a multiple of the wavelength L4 of the corrugation W4 of the outer wall 4.

The following relationships preferably apply: 2 <A6 / A2 <15

2 <A6 / A4 <15

1 <L6 / L2 <20

1 <L6 / L4 <20

10 shows a first profile of the two tube parameters “Thickness D3 of the

Foam material »and« hardness Fl of the foam material »(modulus of elasticity) are shown as a function of the axial coordinate x along the axial direction of the tube according to the invention. D3 and H run in phase here.

11 shows a second profile of the two tube parameters “Thickness D3 of the

Foam material »and« hardness H of the foam material »(modulus of elasticity) as a function of axial coordinate x shown along the axial direction of the tube according to the invention. D3 and H run in opposite phases here.

In addition to the in-phase (Fig. 10) or the opposite phase (Fig. 1 1) between the course W3 of the thickness D3 and the course W3 ^{* of} the hardness F1 (modulus of elasticity), other phase relationships (between 0 and 180 °) can also be between the course W3 and the course W3 ^* can be selected.

Claims

Expectations

1. Pipe (1; 1 1 1 1 ^* ; 1 ^** ), especially for an air distribution system in

Buildings or parts thereof, with an inner wall (2), an outer wall (4) surrounding the inner wall and an intermediate space (3) between the

Inner wall (2) and the outer wall (4), characterized in that the

Intermediate space (3) is filled with a sound-absorbing material (5) at least in partial areas.

2. Pipe according to claim 1, characterized in that the sound-absorbing material (5) fills the entire space (3).

3. Pipe according to claim 1, characterized in that the sound-absorbing material (5) fills the intermediate space (3) in axial partial areas of the pipe.

4. Pipe according to one of claims 1 to 3, characterized in that the outer wall (4) is designed as a corrugated tube (4a, 4b) with wave crests (4a) and wave troughs (4b) extending along the circumferential direction.

5. Pipe according to one of claims 1 to 4, characterized in that the inner wall (2) as a corrugated tube (2a, 2b) with it along the circumferential direction

extending wave crests (2a) and wave troughs (2b) is formed.

6. Pipe according to one of claims 1 to 5, characterized in that the sound-absorbing material (5) comprises a foam material.

7. Pipe according to one of claims 1 to 5, characterized in that the outer wall (4) has a polymer material.

8. Pipe according to one of claims 1 to 6, characterized in that the inner wall (2) comprises a polymer material.

9. Pipe according to claim 6 to 8, characterized in that the foam material has a polymer, in particular an elastomer.

10. Pipe (1; 1 ’) according to one of claims 1 to 9, characterized in that the tube in the intermediate space (3) one from the inner wall (2) to the

Has outer wall (4) extending spacer (6; 7).

1 1. tube (1; 1 ') according to claim 10, characterized in that the

Spacers (6; 7) in the radial direction of the tube has a higher rigidity than in the axial direction of the tube.

12. Pipe (1) according to one of claims 10 to 1 1, characterized in that the spacer (6) is designed as a corrugated tube (6a, 6b) with wave crests (6a) and wave troughs (6b) extending along the circumferential direction.

13. Pipe (1) according to claim 12, characterized in that wave crests (2a) and wave troughs (2b) of the inner wall (2), wave crests (4a) and wave troughs (4b) of the outer wall (4) and wave crests (6a) and Wave troughs (6b) of the spacer (6) are located at the same locations along the axial direction of the tube.

(Corrugations W2, W4, W6 are in phase)

14. Pipe (1) according to one of claims 12 to 13, characterized in that the corrugation W2 of the inner wall (2) and the corrugation W4 of the outer wall (4) each have a smaller amplitude (A2, A4) than the amplitude (A6) the corrugation W6 of the

Have spacers (6) (A2 <A6, A4 <A6).

15. Pipe (1) according to one of claims 12 to 14, characterized in that the inner wall (2) and the outer wall (4) each have a smaller wall thickness (D2, D4) than the wall thickness (D6) of the spacer (6) (D2 <D6, D4 <D6).

16. Pipe (1) according to one of claims 12 to 15, characterized in that the corrugation W2 of the inner wall (2), the corrugation W4 of the outer wall (4) and the

Corrugation W6 of the spacer (6) in the axial direction of the tube all have the same wavelength L (L2 = L4 = L6 = L).

17. Pipe (1) according to one of claims 12 to 15, characterized in that the corrugation W2 of the inner wall (2) and / or the corrugation W4 of the outer wall (4) has a smaller wavelength (L2, L4) than the wavelength (L6 ) of the corrugation W6 of the

Have spacers (6) in the axial direction of the tube (L2 <L6, L4 <L6).

18. Pipe (1 ’”) according to claim 17, characterized in that the wavelength (L6) of the corrugation W6 of the spacer (6) is a multiple of the wavelength (L2) of the corrugation W2 of the inner wall (2), i.e.

L6 = n x L2, where n = 1, 2, 3, 4,, 20.

19. Pipe (1 '”) according to one of claims 17 to 18, characterized in that the wavelength (L6) of the corrugation W6 of the spacer (6) is a multiple of the wavelength (L4) of the corrugation W4 of the outer wall (4), ie

L6 = n x L4, where n = 1, 2, 3, 4, ..., 20.

20. Pipe (1) according to one of claims 12 to 19, characterized in that the spacer (6) has a wall thickness (D6) of 0.2 mm to 3 mm and preferably from 0.5 mm to 1.5 mm.

21. Pipe (1) according to one of claims 12 to 20, characterized in that the spaces (3a, 3b) between the inner wall (2), the outer wall (4) and the spacer (6) with the sound-absorbing material (5) , especially with melamine resin.

22. Pipe (1 ') according to any one of claims 10 to 1 1, characterized in that the spacer (7) is designed as a helical (helical) web (7) which is coaxial with the inner wall (2) and the outer wall ( 4) extends along the axial direction in the intermediate space (3).

23. Pipe (1 ') according to claim 22, characterized in that on the one hand there are wave crests (2a) of the inner wall (2) and troughs (4b) of the outer wall (4) at the same locations along the axial direction of the tube and on the other hand troughs ( 2b) of the inner wall (2) and wave crests (4a) of the

Outer wall (4) are in the same places along the axial direction of the tube. (Corrugations W2, W4 are out of phase)

24. Pipe (1 ') according to any one of claims 22 to 23, characterized in that on the one hand wave crests (2a) of the inner wall (2) and troughs (4b) of the outer wall (4) in the space (3) between the helical web ( 7) protrude and on the other hand wave troughs (2b) of the inner wall (2) extend along a radially inner side (7a) of the helical web (7) and wave crests (4a) of the The outer wall (4) extends along a radially outer side (7b) of the helical web (7).

25. Pipe (1 ') according to any one of claims 22 to 24, characterized in that the radially inner side (7a) and the radially outer side (7b) of the helical web (7) are each convex and into the troughs (2b) protrude the inner wall (2) or protrude into the wave crests (4a) of the outer wall (4).

26. Pipe (1) according to one of claims 22 to 25, characterized in that the spacer (7) has a thickness of 0.2 mm to 5 mm and preferably from 1 mm to 3 mm.

27. Pipe according to one of claims 10 to 26, characterized in that the spacer (6; 7) comprises polymer material.

28. Pipe according to one of claims 10 to 27, characterized in that the spacer (6; 7) has mineral fibers and / or metal fibers.

29. Pipe (1 ”) according to one of claims 4 to 1 1, characterized in that the intermediate space (3) between the outer wall (4a, 4b) formed as a corrugated tube (4a, 4b) and the inner wall (2) with a foam material (5th ) is foamed, which has a periodically fluctuating course W3 of the foam material wall thickness D3 along the axial direction.

30. Pipe according to claim 29, characterized in that the foam material (5) with the radially inner surface of the outer wall (4) is integrally connected, in particular glued and / or welded.

31. Pipe according to claim 29 or 30, characterized in that the

Foam material (5) with the radially outer surface of the inner wall (2)

is integrally connected, in particular glued and / or welded.

32. Pipe according to one of claims 29 to 31, characterized in that the foam material (5) has a periodically fluctuating course W3 ^{* of} the foam material hardness (modulus of elasticity) along the axial direction.

33. Pipe according to claim 32, characterized in that the curves W3 and W3 ^{* are in} phase, ie that maxima (W3 ^* a) and minima (W3 ^* b) of the curve W3 ^{* of} the foam material hardness H and maxima (W3a) and minima (W3b) of Course W3 of the foam material wall thickness D3 are located at the same locations along the axial direction of the tube.

34. Pipe according to claim 32, characterized in that the profiles W3 and W3 ^{* are in} opposite phase, ie that there are minima (W3 ^* b) and maxima (W3 ^* a) of the profile W3 ^{* of} the foam material hardness H and maxima (W3a) and minima (W3b) of the course W3 of the foam material wall thickness D3 are located at the same locations along the axial direction of the tube.

35. Pipe according to one of claims 32 to 34, characterized in that the periodically fluctuating profile W3 ^{* of} the foam material hardness and / or the periodically fluctuating profile W3 of the foam material wall thickness D3 has a smaller wavelength (L3 ^* , L3) than the wavelength (L4) the curl W4 the

Have outer wall (4) (L3 ^* <L4, L3 <L4).

36. Pipe according to claim 35, characterized in that the wavelength L4 of the corrugation W4 of the outer wall (4) is a multiple of the wavelength L3 of the corrugation W3 of the periodically fluctuating course of the foam material wall thickness D3, i.e. L4 = n x L3, where n = 1, 2, 3, 4, ..., 10.

37. Pipe according to claim 35 or 36, characterized in that the wavelength L4 of the corrugation W4 of the outer wall (4) is a multiple of the wavelength L3 ^{* of} the corrugation W3 ^{* of} the periodically fluctuating course of the foam material hardness, ie L4 = nx L3 ^* , where n = 1, 2, 3, 4, ..., 10.

38. Pipe according to one of claims 29 to 37, characterized in that the course W3 of the foam material wall thickness D3 which fluctuates periodically along the axial direction is determined by the corrugation W4 of the outer wall (4).

39. Pipe according to one of claims 29 to 38, characterized in that the course W3 of the foam material wall thickness D3 which fluctuates periodically along the axial direction is determined by a corrugation W2 of the inner wall (2).

40. Pipe according to claim 39, characterized in that the corrugation W4 of the outer wall (4) and the corrugation W2 of the inner wall (2) are in phase.

41. Pipe according to claim 39, characterized in that the corrugation W4 of the outer wall (4) and the corrugation W2 of the inner wall (2) are out of phase.

42. Pipe according to one of claims 39 to 41, characterized in that the wavelength L4 of the corrugation W4 of the outer wall (4) is a multiple of the wavelength L2 of the corrugation W2 of the inner wall (2), i.e. L4 = n x L2, where n = 1, 2, 3, 4, ..., 10.

43. Pipe according to one of claims 29 to 38, characterized in that the course W3 of the foam material wall thickness D3 which fluctuates periodically along the axial direction is determined only by the corrugation W4 of the outer wall (4), i.e. that the inner wall (2) has no corrugation when the pipe is straight and not curved.

44. Pipe (1 ^* ; 1 ^** ) according to one of claims 1 to 9, characterized in that the inner wall (2) and / or the outer wall (4) is connected to a helical (helical) reinforcement (7 '), which extends coaxially to the inner wall (2) and to the outer wall (4) along the axial direction of the tube.

45. Pipe according to claim 44, characterized in that the helical reinforcement (7 ’) is embedded in the outer wall (4).

46. Pipe according to claim 44 or 45, characterized in that the

helical reinforcement (7 ’) with the radially inner surface of the outer wall (4) and with the foam material (5) is integrally connected, in particular welded and / or glued.

47. Pipe according to one of claims 44 to 46, characterized in that the helical reinforcement (7 ') with the radially outer surface of the inner wall (2) and with the foam material (5) is integrally connected, in particular welded and / or glued .

48. Pipe according to one of claims 44 to 47, characterized in that the helical reinforcement (7 ’) is a helically wound strand (7’).

49. Pipe according to one of claims 44 to 48, characterized in that the strand (7 ') has a rectangular cross-section, the long side LS of the rectangle being aligned parallel to the longitudinal direction of the tube and in particular the aspect ratio of the long side LS short side KS of the rectangle is in the range from 1: 1 to 10: 1, ie 1 <LS / KS <10.

50. Pipe according to one of claims 44 to 48, characterized in that the strand (7 ') has an oval cross-section, the long diagonal LD of the oval being aligned parallel to the longitudinal direction of the pipe and in particular the aspect ratio of the long diagonal LD short diagonal KD of the oval lies in the range from 1: 1 to 10: 1, ie 1 <LD / KD <10.

51. Pipe according to one of claims 44 to 50, characterized in that the reinforcement (8) comprises polymer material and / or metal.

52. Pipe according to one of claims 44 to 51, characterized in that the reinforcement (8) has mineral fibers and / or metal fibers.

53. Pipe (1; 1 1 1 '”) according to one of claims 1 to 52, characterized in that the wall thickness (D4) of the outer wall (4) of the pipe is greater than the wall thickness (D2) of the inner wall (2) of the pipe is (D4> D2).

54. Pipe according to one of claims 1 to 53, characterized in that the inner wall (2) has a wall thickness (D2) of 0.05 mm to 0.3 mm and the

Outer wall (4) has a wall thickness (D4) of 0.2 mm to 1.2 mm.

55. Pipe according to one of claims 1 to 54, characterized in that the inner wall (2) on its radially inner surface containing an aluminum

Has coating (8).

56. Pipe according to one of claims 1 to 55, characterized in that it has a circular cross section.

57. Pipe according to one of claims 1 to 55, characterized in that it has a rectangular cross section.

58. Pipe according to one of claims 1 to 55, characterized in that it has a polygonal cross section, in particular a hexagonal cross section.