Corrugated plastic tube for air-conditioning and / or ventilation technology

Abstract

The invention relates to a plastic corrugated tube for air-conditioning and / or ventilation technology, designed as a single-layer or double-layer non-circular corrugated tube (1, 1a) which has a corrugated profile (10) that forms the outer side of the corrugated tube (1, 1a), wherein, in at least one of the circumferential portions (Ui2) with strong curvature (R2), the corrugated profile (10) has a greater corrugation height (H), preferably at least on average a greater corrugation height (H), than in at least one of the circumferential portions (I1) with weak curvature (R1).

Description

[0001] Corrugated plastic pipe for air conditioning and / or ventilation technology

[0002] The invention relates to corrugated plastic pipes with the features according to the preamble of claim 1.

[0003] The invention relates to a preferably non-circular corrugated pipe. The corrugated pipe is manufactured using a corrugator known per se in a known manner. The corrugated pipe can be designed as a single-walled or double-walled corrugated pipe. The double-walled corrugated pipe consists of a substantially smooth inner pipe and an outer pipe having a corrugated profile. The inner pipe is preferably smooth but can also have a slight corrugation. Pipes of this type are used, for example, as part of a room ventilation system in the construction industry, mostly as ventilation pipes. Another application for pipes of this type in the construction industry is as conduits for routing cables.

[0004] These corrugated pipes are primarily evaluated according to the following criteria:

[0005] Size of the cross-sectional area F1 enclosed by the inner skin. This should be as large as possible. In the case of designs as ventilation pipes, the flow space (air duct) enclosed by the inner skin should be as large as possible.

[0006] Suitable for installation purposes, allowing for non-destructive bending with minimal effort. The pipe should be as flexible as possible. Highest possible resistance to external forces (e.g., pressure load) is required.

[0007] The engineering challenge lies in optimizing the aforementioned, sometimes conflicting, criteria by choosing a suitable geometry.

[0008] The state of the art offers a variety of solutions, the essential distinguishing feature of which is the geometric design of the cross-sectional area (oval design, loaf shape, hourglass shape, etc.) and the characteristics of the profile parameters of the wave profile, namely the profile parameters wave width and wave height.

[0009] The invention is based on the objective of creating a plastic corrugated pipe which, despite having a non-circular cross-sectional shape, has the largest possible inner cross-section and exhibits high flexibility for installation purposes and high resistance to damage during operation; preferably, preferred embodiments as flow pipes should have the lowest possible flow resistance.

[0010] The invention solves the problem with the subject matter of main claim 1. This subject matter is a plastic corrugated pipe for air conditioning and / or ventilation technology, designed as a single-layer or double-layer corrugated pipe, which has a corrugated profile that forms the outside of the corrugated pipe.

[0011] Preferably, the corrugated profile is formed from wave crests arranged one behind the other in the direction of the axis of the corrugated tube, with wave troughs arranged between immediately adjacent wave crests, the outer circumference of the corrugated profile is formed by the outer circumference of the wave crests and is non-circular or round, and the inner circumference of the corrugated profile is formed by the outer circumference of the wave troughs and is non-circular.

[0012] The solution according to the invention provides that the inner circumference has one or more circumferential sections with strong curvature and one or more circumferential sections with weak curvature, wherein in at least one of the circumferential sections with strong curvature the wave profile has a greater wave height, preferably at least on average a greater wave height, than in at least one of the circumferential sections with weak curvature.

[0013] This allows for a significantly larger cross-sectional area compared to corrugated pipes, where the profile height H, i.e., the wave height of the corrugated profile, is constant around the circumference. In ventilation pipe applications, this also reduces flow resistance. The inventive design of the corrugated profile with a large profile height H in a circumferential section of strong curvature is crucial for achieving resistance to external forces (for example, achieving the test force according to DIN EN ISO 61386-24). In a circumferential section of weak curvature, however, the profile height H can be smaller, as this area preferably contributes only minimally to achieving the required test forces. Consequently, in the inventive design, the cross-sectional area F increases while maintaining virtually the same resistance. Circumferential sections with weak curvature, i.e.,Curvatures with a small radius of curvature R can be concave or convex. However, so-called weak curvature can also have an infinitely large radius of curvature, resulting in a straight line or another curve shape.

[0014] The profile geometry is preferably designed such that a continuous transition occurs between the different wave heights. This can mean that the wave height H preferably has a minimum in a central region of a circumferential section with slight curvature and a maximum in a central region of a circumferential section with strong curvature.

[0015] The wave profile can also be designed in such a way that the respective minimum of the profile height, preferably in the circumferential section of weak curvature, or the respective maximum of the profile height, preferably in the circumferential section of strong curvature, extends over a larger area, for example, the profile height in the circumferential section of strong curvature is at its maximum throughout the entire circumferential section.

[0016] Particularly preferred embodiments are described by the features of the dependent claims. Regarding the various circumferential sections, i.e.,

[0017] Regarding the distinction between sections of the circumference with strong curvature and those with weak curvature, the terms "strong curvature" and "weak curvature" primarily refer to the fact that the curvature is greater in the section with strong curvature than in the section with weak curvature. Strong curvature means a relatively small radius of curvature, which can be constant or varying within the relevant section. Weak curvature means a relatively large radius of curvature, which can also be constant or varying across the section. Weak curvature also includes a linear profile, i.e., an infinite radius of curvature, and especially a concave shape.

[0018] In preferred embodiments, the inner circumference may have at least two, preferably opposing, circumferential sections with a strong curvature and at least two, preferably opposing, circumferential sections with a weak curvature. The cross-sectional shape of such tubes may be symmetrical or asymmetrical with respect to the inner circumference. Preferred embodiments may provide that two adjoining, adjacent circumferential sections of the inner circumference, one of which is a circumferential section with a strong curvature and the other a circumferential section with a weak curvature, transition smoothly into one another with respect to the different wave height of the corrugation profile and / or with respect to their different curvature, preferably forming a continuous transition section.

[0019] In particularly preferred embodiments, the design of the wave profile within the circumferential section of strong curvature, i.e., viewed along this circumferential section, can be provided in such a way that within one or more, preferably each, of the circumferential sections with strong curvature in the wave profile along the circumferential section, the wave height and / or the curvature of the circumferential section is constant or variable, preferably forming one, preferably convex, maximum or several maxima, preferably alternately variable.

[0020] Preferred further training may stipulate that the course of the varying profile height and / or curvature is continuous along the circumferential section of strong curvature.

[0021] In special embodiments, the design of the wave profile within the circumferential section of slight curvature, i.e., the design along this circumferential section, may include the provision that within one or more, preferably each, of the circumferential sections with slight curvature in the wave profile along the circumferential section, the wave height and / or the curvature of the circumferential section is designed as variable, preferably varying by forming a preferably concave minimum or several minima, preferably varying alternately.

[0022] Preferred further developments may stipulate that the course of the varying wave height and / or curvature is continuous along the circumferential section of weak curvature.

[0023] Preferred embodiments may provide, with regard to the shape of the inner circumference and / or the shape of the outer circumference, that the shape of the inner circumference and / or the shape of the outer circumference is non-circular, preferably as an elliptical shape and / or as an hourglass shape and / or as a loaf of bread, wherein it is preferably provided that, in modification of one or more of the above-mentioned non-circular shapes, at least one or both of the opposing circumferential sections of slight curvature are convex and / or concave and / or have a linear profile at least in sections.

[0024] Preferred embodiments may provide that the shape of the inner circumference and / or the shape of the outer circumference is non-circular.

[0025] - is shaped like an ellipse and / or

[0026] - is shaped like an hourglass and / or

[0027] - is designed as a bread loaf shape and / or

[0028] - is designed as a modified elliptical shape such that, in a modification of the elliptical shape, both of the opposite longitudinal sides of the outer circumference, which correspond to the circumferential sections of the inner circumference with slight curvature, are flattened and parallel with at least a partially linear profile, wherein in the elliptical shape modification it is preferably provided that both of the opposite longitudinal sides of the inner circumference, which form the circumferential sections of the inner circumference with slight curvature, are convexly curved. Preferred embodiments of the elliptical shape, the hourglass shape, the loaf shape, and / or the elliptical shape modification are each corrugated tubes having an elongated cross-section.They are preferably designed such that on the opposite long sides of the cross-section the circumferential sections of the inner tube and the outer circumference have slight curvature and on the opposite short sides of the cross-section the circumferential sections of the inner circumference and the outer circumference have strong curvature.

[0029] In an elliptical shape, the circumferential segments of the inner and outer circumferences formed on opposite long sides can be convex in cases of slight curvature, meaning they exhibit a convex profile on both the inner and outer circumferences along the two opposite long sides. On opposite short sides, the circumferential segments of the inner and outer circumferences are convex in cases of strong curvature.

[0030] In the hourglass shape, the circumferential sections of the inner and outer circumferences formed on the long sides are concave in the case of slight curvature; that is, the inner and outer circumferences run concave in the region of the opposite long sides. On the opposite short sides, the circumferential sections of the inner and outer circumferences are convex in the case of strong curvature.

[0031] In the loaf-shaped mold, the circumferential sections of the inner and outer circumferences formed on the long sides are shaped differently. On one long side, the circumferential sections of the inner and outer circumferences are flattened, so that the outer circumferential sections are linear, at least in the central region, i.e., parallel to the longitudinal axis of the cross-section. The circumferential sections of the inner circumference are also flattened, but preferably still convex. On the opposite long side, the circumferential sections of the inner and outer circumferences are each convex, i.e., not flattened. On the opposite short sides, the circumferential sections of the inner and outer circumferences are each convex with a strong curvature.

[0032] Preferred embodiments may provide that the shape of the outer circumference is non-circular, a modification of the ellipse, wherein, in a modification of the ellipse shape, both of the opposite longitudinal sides of the outer circumference, which are assigned to the inner circumference sections with slight curvature, are flattened and parallel with at least a partially linear profile; and / or that the shape of the inner circumference is an ellipse, wherein the opposite circumference sections with slight curvature are convex.

[0033] Particularly preferred embodiments, especially further developments of the preceding embodiments, may provide that the outer cross-section of the corrugated tube formed by the outer circumference of the corrugated profile has a cross-sectional height oriented along the small axis of at least 48.5 mm to a maximum of 52.0 mm and a cross-sectional width oriented along the large axis of at least 139.7 mm to a maximum of 142.3 mm.

[0034] Regarding the design of the wave profile, particularly preferred embodiments provide that the profile parameters wave height and wave width vary along the inner circumference of the wave profile, and preferably also the wave root width and / or wave rise angle and / or pitch vary, such that in the circumferential section of strong curvature the wave height has the value H2, the wave width the value B2, the wave root width the value A2 / 2, the wave rise angle the value a2 and the pitch the value T2, and in the circumferential section of weak curvature the wave height has the value H1, the wave root width the value A1 / 2, the wave rise angle the value cd and the pitch the value T1, wherein the wave height and the wave width form the following relationship:

[0035] Relation 1 (wave profile variant 1): H2 > H1 and B2 = B1 or

[0036] Relation 2 (wave profile variant 2): H2 > H1 and B2 + B1 , preferably B2 > B1 or

[0037] Relation 3 (wave profile variant 3): H2 > H1 and B2 < B1

[0038] Preferred further training options may include:

[0039] Relation 1.1: that relation 1 (wave profile variant 1) holds in combination with one or more of the following relations:

[0040] A2 / 2 < A1 / 2 a2 = a1

[0041] T2 = T1 or

[0042] Relation 1.2: that relation 2 (wave profile variant 2) holds in combination with one or more of the following relations:

[0043] A2 / 2 < A1 / 2 a2 + a1, preferably a2 < a1

[0044] T2 = T1 or

[0045] Relation 1.3: that relation 3 (wave profile variant 3) holds in combination with one or more of the following relations:

[0046] A2 / 2 = A1 / 2 a2 + a1, preferably a2 > a1 T2 = T1

[0047] The invention preferably also relates to a pair of forming jaws for use in a corrugator for producing a corrugated tube according to one of the claims directed to the corrugated tube, wherein the pair of forming jaws is formed from a first forming jaw and a second forming jaw, i.e., for example, a left forming jaw or a right forming jaw, and the inner forming surface of the pair of forming jaws is formed by the opposing inner surfaces of the first and second forming jaws. According to the invention, it can be provided that the inner forming surface of the pair of forming jaws is complementary to the outer surface of the plastic corrugated tube to be produced.

[0048] In particularly preferred embodiments, a particularly cost-effective manufacturing process for the mold jaws may be provided. For example, the mold jaw pair may be manufactured by first milling the inner surface of the first and second mold jaws to produce the inner mold surface, creating exclusively circumferential sections of strong curvature, and then, in a second step, milling away one or more of the circumferential sections of strong curvature produced in the first step, creating one or more circumferential sections of weak curvature.

[0049] The invention will be explained in more detail below with reference to drawings.

[0050] Figures 1a-1d show the cross-section of the corrugated pipe perpendicular to the pipe axis for four corrugated pipe designs that differ in the shape of the pipe cross-section, as follows:

[0051] Fig. 1 a: Cross-section of the corrugated pipe design A;

[0052] Fig. 1 b: Cross-section of the corrugated pipe design B;

[0053] Fig. 1c: Cross-section of the corrugated pipe design C;

[0054] Fig. 1d: Cross-section of the corrugated pipe design D;

[0055] Fig. 1.1x and

[0056] Fig. 1.1y: Longitudinal sections of a corrugated profile variant 1 in the corrugated pipe designs of Fig. 1a to 1d, wherein Fig. 1.1x is a longitudinal section along the horizontal section plane XX in Fig. 1a to 1d and Fig. 1.1y is a longitudinal section along the vertical section plane YY in Fig. 1a to 1d;

[0057] Fig. 1.2x and

[0058] Fig. 1,2y: Longitudinal sections of a corrugated profile variant 2 in the corrugated pipe designs of Fig. 1a to 1d, where Fig. 1,2x is a longitudinal section along the horizontal section plane XX in Fig. 1a to 1d and Fig. 1,2y is a longitudinal section along the vertical section plane YY in Fig. 1a to 1d;

[0059] Fig. 1.3x and

[0060] Fig. 1,3y: Longitudinal sections of a wave profile variant 3 in the corrugated pipe designs of Figs. 1a to 1d, where Fig. 1,3x is a longitudinal section along the horizontal section plane XX in Figs. 1a to 1d and Fig. 1,3y is a longitudinal section along the vertical section plane YY in Figs. 1a to 1d, each with wave profile parameters shown in the sense of a graphical geometric definition of the parameters; Fig. 2 perspective view of a pair of forming jaws:

[0061] The illustrated embodiments are plastic composite pipes designed as double-layered corrugated pipes with a corrugated outer pipe 1a and a largely smooth inner pipe 1i, which is arranged coaxially with the axis RA of the corrugated pipe in the corrugated outer pipe 1a and is preferably welded to the troughs of the corrugations of the outer pipe 1a. The corrugated outer pipe 1a and the smooth inner pipe 1i are visible in section in the longitudinal sectional views Fig. 1, 1x and y to Fig. 1, 3x and y.

[0062] Figures 1a to 1d show four different corrugated pipe designs A, B, C and D. The designs differ in the shape of the corrugated pipe cross-section, i.e., in the shape of the inner circumference Ui, which is formed by the circumferential contour of the inner tube 1i.

[0063] In appropriate designs of single-walled corrugated tubes, the inner circumference Ui is formed by the circumferential contour formed by the corrugation troughs.

[0064] The inner circumference Ui of corrugated pipe designs A, B, C, and D is non-circular, as can be seen in the cross-sectional views. The outer circumference Ua, formed by the contour of the outer circumference of the corrugation crests, is also non-circular in designs A, B, C, and D, as can be seen in the cross-sectional views, but its shape deviates slightly from that of the inner circumference Ui in certain sections.

[0065] In the corrugated tube design A in Fig. 1a, the shape of the inner circumference Ui is elliptical with a large horizontal axis a1 and a small vertical axis a2. The circumferential contour is symmetrical about both the horizontal and vertical central axes. The circumference Ui has two opposing circumferential sections Ui2 with strong curvature and a small radius of curvature R2, and two opposing circumferential sections Ui1 with weak curvature and a large radius of curvature R1. The circumferential sections connect tangentially and continuously to each other, forming the symmetrical elliptical shape of the inner circumference Ui.

[0066] The corrugated pipe design B in Fig. 1b is also symmetrical. However, unlike design A, the slightly curved circumferential sections Ui1 in design B are not convex, but concave. This cross-sectional shape is known in practice as an hourglass shape.

[0067] The corrugated pipe design C in Fig. 1c differs from the corrugated pipe designs A and B in that, in the case of corrugated pipe design C, the opposing circumferential sections Ua1 are linearly parallel to each other, in order to form flat bearing surfaces on these opposite sides. The opposing slightly curved circumferential sections Ui1 are convex or at least partially linear in the central region.

[0068] The corrugated tube design D in Fig. 1d is referred to in practice as a loaf shape.

[0069] The cross-sectional shape is asymmetrical. The opposing sections Ui1 are designed differently in this case. The lower circumferential section Ui1 is very slightly curved. The associated lower circumferential section Ua1, formed on the outer circumference Ua, is linear, i.e., its radius of curvature is infinite, in order to form a bearing surface for the pipe. The upper circumferential section Ui1 is convexly curved, and more strongly curved than the opposing circumferential sections Ui1 in the corrugated pipe design A in Fig. 1a. It is essential that, in all the corrugated pipe designs A to D shown, as can be seen from the comparison of the profiles of Ui and Ua in Figs. 1a to 1d, the profile height H is greater in the strongly curved circumferential sections Ui2 than in the circumferential sections Ui1.Within the circumferential sections Ui2 and Ui1, the profile height H is approximately constant, with a minimum profile height H occurring in the central region of the slightly curved circumferential sections Ui1. In the transition area between the circumferential sections Ui2 and Ui1, the transition between the larger profile height H and the smaller profile height H is continuous in the embodiments shown in the figures, as can also be seen from the course of Ui and Ua in Figures 1a to 1d.

[0070] The wave profile parameters H, B, T, A, and a are shown in detail in Figures 1, 1x and y to 1, 3x and y. These figures show three different wave profile variants, namely variants 1, 2, and 3. These wave profile variants are each implemented in the corrugated pipe designs A to D of Figures 1a to 1d, which differ in their cross-sectional shape.

[0071] Figures 1,1x and 1,1y show wave profile variant 1.

[0072] Figures 1,2x and 1,2y show wave profile variant 2.

[0073] Figures 1,3x and 1,3y show wave profile variant 3.

[0074] Figures labelled with index x each show section XX in the strongly curved circumferential section Ui2 of figures 1a to 1d. Figures labelled with index y each show section YY in the less curved or straight circumferential section Ui1 of figures 1a to 1d.

[0075] The profile parameters shown in Figs. 1.1x and 1.1y to 1.3x and 1.3y are H: profile height or wave height of the wave profile;

[0076] B: Wave width of the wave profile;

[0077] T: Division of the wave profile;

[0078] A / 2: Wave base width; cc: Wave rise angle.

[0079] A comparison of the sectional views designated with index x Fig. 1.1x, Fig. 1.2x and Fig. 1.3x (section plane XX in the circumferential section Ui2) with the sectional views designated with index y Fig. 1.1y, Fig. 1.2y and Fig. 1.3y (section plane Y-Y in the circumferential section Ui1) shows how the profile parameters vary over the circumference Ui.

[0080] In the following, the profile parameters H, B, T, a, A / 2 from section plane XX are denoted by index x and from section plane YY by index y and are compared with each other. The following relationships result for the individual profile variants 1, 2 and 3:

[0081] Wave profile variant 1 (Fig. 1.1 x and 1.1 y)

[0082] Hx > Hy

[0083] Bx = By

[0084] Tx = Ty ax = ay Ax / 2 < Ay / 2

[0085] Wave profile variant 2 (Fig. 1 ,2x and 1 ,2y)

[0086] Hx > Hy

[0087] Bx > By

[0088] Tx = Ty ax < ay Ax / 2 < Ay / 2

[0089] Wave profile variant 3 (Fig. 1, 3x and 1, 3y) Hx > Hy Bx < By Tx = Ty ax > ay Ax / 2 = Ay / 2

[0090] The corrugated tubes that implement profile variants 1, 2 and 3 differ in the following technical properties:

[0091] Corrugated tubes with a corrugation profile formed according to corrugation profile variant 1 offer manufacturing advantages. These advantages lie in the fact that the dies used for manufacturing such corrugated tubes are particularly easy to produce. These dies can be manufactured by first milling the inner surface of the dies of a pair of dies with a uniform corrugation profile across the entire circumference, using the same profile parameters as the cutting plane XX, i.e., the parameters Hx, Bx, Tx, Ax / 2, ax. In a second step, the resulting uniform corrugation profile is then further machined only in the circumferential sections Ui1 by milling, reducing the profile height Hx to the profile height Hy.In these profile sections, the additional profile parameters Bx, Tx, Ax / 2, and ax are automatically determined. The two-stage manufacturing process, possible with this corrugation profile variant, makes the production of the forming jaws very simple, i.e., simpler than the single-stage production of forming jaws with different corrugation profiles in different circumferential sections by milling. The forming jaws, which are manufactured in two stages as described above, produce corrugated pipes with the corrugation profile according to profile variant 1 when used in the corrugator. Corrugated pipes with the corrugation profile according to profile variant 1 are therefore advantageous from a manufacturing perspective due to their simple production. The stiffness against compressive loads from external pressure acting on the opposite, less curved or flat sides, and the flexibility of the corrugated pipe for installation purposes, are sufficiently good as a compromise.

[0092] Such a pair of forming jaws 20 with left forming jaw 21 and right forming jaw 22 and an inner forming surface 25 formed on the inner side of the forming jaws facing each other is shown in Fig. 2.

[0093] Regarding the properties of the corrugated pipes according to the corrugated profile variants 2 and 3:

[0094] Corrugated pipes with a wave profile according to profile variant 2 have a wider wave shape and therefore increased stiffness against pressure acting on the opposite flat sides of the corrugated pipe.

[0095] Corrugated pipes with a wave profile according to profile variant 3 have a particularly narrow wave shape and offer particularly good flexibility during installation.

[0096] A common feature of the corrugated pipes with corrugated profiles of variants 1, 2, and 3 is that they each have a significantly higher profile height H in the circumferential sections of high curvature (i.e., in circumferential sections Ui2) than in the circumferential sections of low curvature (i.e., in circumferential sections Ui1). This common feature of profile variants 1, 2, and 3 is essential for obtaining large cross-sectional areas with the given non-circular cross-sectional shape. These areas are advantageous for airflow in the case of ventilation pipes and for large-volume pipes used to guide cables or similar items. In both cases, they ensure high compressive strength against damage from external pressure, particularly when the pressure is applied to the opposite flat sides of the corrugated pipe.

[0097] The definitions of the profile parameters H, B, T, A / 2, and a are derived from the sectional views in Figures 1.1x and 1.1y, 1.2x and 1.2y, and 1.3x and 1.3y, in which the profile parameters are defined graphically / geometrically. The sectional views in these figures show a network of exemplary embodiments of corrugated tubes.

[0098] In the following Table 1, the profile parameters are additionally defined mathematically / geometrically based on the sectional views of the figures mentioned.

[0099] Table 1 Definitions of the profile parameters of the corrugated profile of corrugated pipes

[0100] 1.1 Profile height H

[0101] The profile height H is the radial distance between the outside of the pipe in the area of ​​a wave crest and the outside of the pipe in the area of ​​an adjacent wave trough.

[0102] 1.2 Division T

[0103] The division T is the axial distance between two geometrically repeating points along the axial pipe direction. The division T is typically measured between the bisector of one wave trough and the bisector of the adjacent wave trough.

[0104] 1.3 Wave trough width A of a wave trough. The wave trough width A is the axial distance between the imaginary intersection point of the left profile flank tangent and the axial extension line of the outside of the wave trough and the imaginary intersection point of the right profile flank tangent and the axial extension line of the outside of the wave trough.

[0105] The profile flank tangent is the tangent to the outside of the profile flank in the region of the midpoint of the profile height H, i.e., the tangent at H / 2 and / or the tangent to the outside of the profile flank in the middle region of the profile flank's path. This applies to waves with profile flanks where the majority of the profile flank's path is linear, i.e., has a constant slope, e.g., waves where the profile flank has a constant slope over a predominant part of the extent of the associated profile height H, for example, approximately 70% of the extent of the associated profile height H.

[0106] For waves with profile flanks where the majority of the profile flank has a convex curve, the profile flank tangent is a fictitious tangent formed as a line of intersection through the profile flank with the first intersection point at 2 / 3 of the profile height, i.e., 2 / 3H, and the second intersection point at 1 / 3 of the profile height, i.e., 1 / 3H.

[0107] 1.4 Profile width B of a wave crest

[0108] The profile width B is the axial distance between the imaginary intersection of the left profile flank tangent and the axial extent line of the outer surface of the wave crest, and the imaginary intersection of the right profile flank tangent and the axial extent line of the outer surface of the wave crest. The profile flank tangent is the tangent to the outer surface of the profile flank in the region of the midpoint of the profile height H, i.e., the tangent at H / 2 and / or the tangent to the outer surface of the profile flank in the middle region of the profile flank's path. This applies to waves with profiled flanks where the majority of the profile flank's path is linear, i.e., constant slope, for example, waves where the profile flank has a constant slope over a predominant part of the extent of the associated profile height H, for instance, approximately 70% of the extent of the associated profile height H.

[0109] For waves with profile flanks where the majority of the profile flank has a convex curve, the profile flank tangent is a fictitious tangent formed as a line of intersection through the profile flank with the first intersection point at 2 / 3 of the profile height, i.e., 2 / 3H, and the second intersection point at 1 / 3 of the profile height, i.e., 1 / 3H.

[0110] 1.5 Profile angle a

[0111] The profile angle a of a wave crest is the angle between the radial line that bisects the profile width B and the profile flank tangent to the profile flank of the wave crest.

[0112] The profile flank tangent is the tangent to the outside of the profile flank in the region of the midpoint of the profile height H, i.e., the tangent at H / 2 and / or the tangent to the outside of the profile flank in the middle region of the profile flank's path. This applies to waves with profile flanks where most of the path of the profile flanks has a linear course, i.e., a constant slope, e.g., for waves where the profile flank has a constant slope over a predominant part of the extent of the associated profile height H, for example, approximately 70% of the extent of the associated profile height H. For waves with profile flanks where most of the path of the profile flank has a convex curve, the profile flank tangent is a fictitious tangent formed as the line of intersection through the profile flank with the first intersection point at 2 / 3 of the profile height d, i.e., 2 / 3H, and second intersection point at 1 / 3 profile height, i.e. 1 / 3H.

[0113] Reference symbol:

[0114] RA axis of the corrugated pipe, pipe axis a1 major axis of the pipe cross-section a2 minor axis of the pipe cross-section lla outer circumference

[0115] Ui inner circumference

[0116] Ui1 Circumferential section of weak curvature

[0117] Ui2 circumferential section of strong curvature

[0118] R1 radius of curvature of weak curvature, large radius of curvature

[0119] R2 radius of curvature of strong curvature, small radius of curvature

[0120] H Wave height of the wave profile, profile height

[0121] B Wave width of the wave profile, profile width of a wave crest

[0122] T division of the wave pro

[0123] A / 2 wave foot width

[0124] A wave trough width a wave rise angle, profile angle

[0125] 1 corrugated pipe

[0126] 1 a corrugated outer tube

[0127] 1 i inner tube

[0128] 10 wave profile

[0129] 10b Wellenberg

[0130] 10t wave trough

[0131] 20 pairs of baking molds

[0132] 21 first baking

[0133] 22 second baking

[0134] 25 inner forming surface of the forming jaw pair

Claims

Claims 1. Plastic corrugated pipe for air conditioning and / or ventilation technology, designed as a single-layer or double-layer corrugated pipe (1 , 1 a) which has a corrugated profile (10) that forms the outside of the corrugated pipe (1 , 1a), wherein it is provided that - that the wave profile (10) is formed from wave crests (10b) arranged one behind the other in the direction of the axis (RA) of the corrugated tube (1 , 1 a) with wave troughs (10t) arranged between immediately adjacent wave crests (10b), - that the outer circumference (11a) of the wave profile (10) is formed by the outer circumference of the wave crests (10b) and is non-circular or round, that the inner circumference (Ui) of the wave profile (10) is formed by the outer circumference of the wave troughs (10t) and is non-circular, characterized in that the inner circumference (Ui) has one or more circumferential sections (Ui2) with strong curvature (R2) and one or more circumferential sections (Ui1) with weak curvature (R1), wherein in at least one of the circumferential sections (Ui2) with strong curvature (R2) the wave profile (10) has a greater wave height (H), preferably at least on average a greater wave height (H), than in at least one of the circumferential sections (11) with weak curvature (R1).

2. Corrugated plastic tube according to claim 1, characterized in that the inner circumference (Ui) has at least two, preferably opposing, circumferential sections (Ui2) with strong curvature (R2) and at least two, preferably opposing, circumferential sections (11) with weak curvature (R1).

3. Corrugated plastic tube according to one of the preceding claims, characterized in that two adjoining, neighboring circumferential sections (11 , I2) of the inner circumference (I), one of which is designed as a circumferential section (I2) of strong curvature (R2) and the other as a circumferential section (11 ) of weak curvature (R1 ), transition continuously into one another with respect to the different wave height (H) of the wave profile (10) and / or with respect to their different curvature (R2, R1 ), preferably forming a continuous transition section.

4. Corrugated plastic tube according to one of the preceding claims, characterized in that within one or more, preferably each of the circumferential sections (I2) with strong curvature (R2) in the corrugated profile (10) along the circumferential section the wave height (H) and / or the curvature (R2) of the circumferential section is formed as constant or variable, preferably forming one, preferably convex maximum or several maxima variably, preferably alternately variably.

5. Corrugated plastic pipe according to claim 4, characterized by the fact that the course of the varying profile height (H) and / or curvature (R2) along the circumferential section (I2) of strong curvature (R2) is continuous.

6. Corrugated plastic tube according to one of the preceding claims, characterized in that within one or more, preferably each of the circumferential sections (Ui1 ) with slight curvature (R1 ) in the corrugated profile (10) along the circumferential section (11 ) the wave height (H) and / or the curvature (R1 ) of the circumferential section is designed as variable, preferably varying by forming a preferably concave minimum or several minima, preferably varying alternately.

7. Corrugated plastic tube according to claim 6, characterized in that the course of the varying wave height (H) and / or curvature (R1) along the circumferential section (11) of slight curvature is continuous.

8. Corrugated plastic tube according to one of the preceding claims, characterized in that the shape of the inner circumference (Ui) and / or the shape of the outer circumference (Ua) is non-circular, preferably as an elliptical shape and / or as an hourglass shape and / or as a loaf shape, wherein it is preferably provided that, in modification of one or more of the above-mentioned non-circular shapes, at least one or both of the opposing circumferential sections (Ui1, Ui1) of slight curvature (R1, R1) are convex and / or concave. and / or are formed with at least a section-wise linear course.

9. Corrugated plastic tube according to one of the preceding claims, characterized in that the shape of the inner circumference (Ui) and / or the shape of the outer circumference (Ua) is non-circular - is shaped like an ellipse and / or - is shaped like an hourglass and / or - is designed as a bread loaf shape and / or - is modified as an elliptical shape modification in such a way that, in a modification of the elliptical shape, both of the opposite longitudinal sides of the outer circumference (Ua), which are assigned to the circumferential sections (Ui1 , Ui1 ) of the inner circumference (Ui) with slight curvature (R1 , R1 ), are flattened with at least sectionally linear progression and are parallel, wherein in the elliptical shape modification it is preferably provided that both of the opposite longitudinal sides of the inner circumference (Ui), which form the circumferential sections (Ui1 , Ui1 ) of the inner circumference (Ui) with slight curvature (R1 , R1 ), are convexly curved.

10. Corrugated plastic tube according to one of the preceding claims, characterized in that the shape of the outer circumference (Ua) is non-circular, forming a modification of the elliptical shape, wherein, in modification of the elliptical shape, both of the opposite longitudinal sides of the outer circumference (Ua), which are assigned to the inner circumference sections (Ui1, Ui1) of the inner circumference (Ui) with slight curvature (R1, R1), are flattened with at least partially linear progression and are parallel; and / or that the shape of the inner circumference (Ui) is formed as an ellipse, with the opposing circumferential sections (Ui1 , Ui1 ) having a slight curvature (R1 , R1 ) being convex.

11. Corrugated plastic tube according to one of the preceding claims, characterized in that the outer cross-section of the corrugated tube (1 , 1 a) formed by the outer circumference (Ua) of the corrugated profile (10) has a cross-sectional height oriented along the small axis (a2) of a minimum of 48.5 mm to a maximum of 52.0 mm and a cross-sectional width oriented along the large axis (a1 ) of a minimum of 139.7 mm to a maximum of 142.3 mm.

12. Corrugated plastic tube according to one of the preceding claims, characterized in that the profile parameters wave height (H) and wave width (B) vary along the inner circumference (Ui) in the corrugated profile (10), and preferably also the wave root width (A / 2) and / or wave rise angle (a) and / or pitch (T) vary, or vary in that in the circumferential section (Ui2) of strong curvature (R2) the wave height (H) has the value H2, the wave width (B) the value B2, the wave root width (A / 2) the value A2 / 2, the wave rise angle (a) the value a2 and the pitch (T) the value T2, and in the circumferential section (Ui1) of weak curvature (R1) the wave height (H) has the value H1, the wave root width (A / 2) the value A1 / 2, the wave rise angle (a) the value a1 and the pitch (T) the value T1 exhibits, where the wave height (H) and the wave width (B) form the following relationship: - Relation 1 (wave profile variant 1): H2 > H1 and B2 = B1 or - Relation 2 (wave profile variant 2): H2 > H1 and B2 + B1 , preferably B2 > B1 or - Relation 3 (wave profile variant 3): H2 > H1 and B2 < B1 13. Corrugated plastic pipe according to claim 12, characterized in that Relation 1.1: that relation 1 (wave profile variant 1) holds in combination with one or more of the following relations: - A2 / 2 < A1 / 2 - a2 = a1 - T2 = T1 or Relation 1.2: that relation 2 (wave profile variant 2) holds in combination with one or more of the following relations: - A2 / 2 < A1 / 2 - a2 + a1, preferably a2 < a1 - T2 = T1 or Relation 1.3: that relation 3 (wave profile variant 3) holds in combination with one or more of the following relations: - A2 / 2 = A1 / 2 - a2 + a1, preferably a2 > a1 - T2 = T1 14. Forming jaw pair for use in a corrugator for the production of a plastic corrugated tube according to one of the preceding claims, wherein the forming jaw pair is formed from a first forming jaw and a second forming jaw and an inner forming surface of the forming jaw pair is formed by opposing inner surfaces of the first and the second forming jaw, characterized in that the inner forming surface of the forming jaw pair is complementary to the outer surface of the plastic corrugated tube to be produced.

15. Forming jaw pair according to claim 14 for producing a corrugated tube according to relation 1 (profile variant 1) of claim 12 and / or according to relation 1.1 of claim 13, characterized in that the forming jaw pair is manufactured by milling out the inner surface of the first and the second forming jaw in a first step to produce the inner forming surface, producing exclusively circumferential sections (Ui2) of strong curvature (R2), and in a second step milling off one or more of the circumferential sections (Ui2) of strong curvature (R2) produced in the first step, producing one or more circumferential sections (Ui1) of weak curvature (R1).

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