WO2009071501A1

WO2009071501A1 - Pipe with an outer lateral surface modified by a surface profile

Info

Publication number: WO2009071501A1
Application number: PCT/EP2008/066502
Authority: WO
Inventors: Wolfgang Berger; Antje Clasen
Original assignee: Fitr-Gesellschaft Für Innovation Im Tief- Und Rohrleitungsbau Weimar M.B.H.
Priority date: 2007-12-05
Filing date: 2008-12-01
Publication date: 2009-06-11
Also published as: DE102008030423B4; DE102008030423A1

Abstract

The invention relates to a pipe with an outer lateral surface (2) that is modified by a surface profile. Said pipe in characterised in that the surface profile comprises projections (3) that extend from the outer lateral surface and that are distributed on the outer surface of said pipe.

Description

Tube with an outer surface modified by a surface profile

description

The invention relates to a tube with a modified by a surface profile outer surface according to the preamble of claim 1.

Such pipes are widely used in practice. They play an important role in the transport of fluid media and in the transfer of heat energy between a medium flowing inside the tube and an external environment. The use of these pipes is determined by basic parameters such as cross section, pipe material, surface quality, inside and outside diameter, wall thickness and pressure rating. Tubes are made of very different materials, such as steel, ceramic, light metal or plastic, and are usually not flexible.

According to the prior art, a tube is generally designed as an elongated hollow cylinder having a base and top surface and a lateral surface as a wall. As a rule, the length of the hollow cylinder is much larger than its cross section. Both the inside and the outside of the wall can be provided with surface modifications. For this purpose, there is an extensive state of the art.

The documents AT 329 608 B, AT 48 697 E, DE 102 10 016 B9, DE 100 41 919 C, DE 2 209 325 A, DE 60 005 089 T2, DE 835 156 B and DE 1 122 971 B describe embodiments in on the inner surface of a tube ribs or other internals are arranged to improve the heat transfer properties of the tube.

Patent specification AT 329 608 B describes helical ribs in the interior of the tube for generating turbulence without an increase in the flow resistance. In the document DE 4 345 045 Al, a mounting element in the form of a wire spiral is described, with which the heat transfer performance is to be optimized. Ribs are also in DE 600 05 beautiful profile, which can increase the heat exchange coefficient.

The ribs can also be incorporated in connection with a profile insert in the tube interior, as described in WO 1995 025 937 Al.

Moldings and structures on the outer tube surface are described, for example, in the publications DE 100 27 71 B, DE 4 404 357 C1 and DE 69 526 907 T2. These are either formed as a corrugated metal band wrapped helically around the tube wall, or annular or helical circumferential ribs, the latter having notches which increase their surface area.

All known pipes belonging to the cited prior art have surface-modifying structures both inside the pipe and on the pipe outside. By known from the prior art embodiments of the outer circumferential surfaces no optimal improvement of the heat exchange is possible. In addition, the known formations require additional material, manufacturing and cost. With changed inner surfaces, the flow resistance and the weight of the tube increases. In addition, here also increases the production cost. Deflection elements, such as ribs, sheets and the like, moreover lead to a change in the direction of flow of the fluid and to a negative influence on the fluidic properties of the pipe.

It is therefore the object to provide a tube that has a significantly better functionality compared to the known from the prior art tubes. Furthermore, there is the task of specifying a tube which has advantageous properties in particular when laying or moving in the ground.

The object is achieved with a tube with a surface profile modified by a outer circumferential surface, wherein the tube according to the invention characterized in that the surface profile of the outer circumferential surface outgoing, distributed on the outer circumferential surface pimples has.

The thus shaped outer circumferential surface thus extends into the environment of the tube, whereby an intimate thermal contact between the outer circumferential surface and the environment arises at a considerably enlarged surface.

The thereby achieved surface enlargement of the outer circumferential surface causes a particularly good heat transfer to the environment. For this reason, disposed within the tube means for increasing the heat transfer, in particular arranged on the pipe inner wall profiles and shapes completely eliminated. Therefore, the inner circumferential surface expediently has a smooth surface profile.

In one embodiment, the knobs are substantially parallel to each other. In a further embodiment, the nubs are oriented substantially perpendicular to the outer circumferential surface. However, an angular orientation of the knobs is also possible in a further variant.

The nubs can be arranged to each other in different ways. In an expedient embodiment, the nubs are evenly spaced from each other. Advantageously, a regular arrangement of the knobs in a the outer circumferential surface at least partially covering pattern.

In a further embodiment, the nubs form an irregular pattern, which covers the outer circumferential surface in sections.

The knobbed shape may vary. In a first embodiment, the nubs on a prismatic shaped knob shaft. In further embodiments, the nub shaft is conical or pyramid-shaped. These different shapes can be supplemented by a number of different Noppenkopfformen. In a first embodiment, the knobs have a flattened knobbed head. In a second embodiment, the knobbed head is sharpened. In a third embodiment, the knobbed head is rounded.

Finally, the knobs may be hemispherical in shape.

The tube according to the invention will be explained in more detail below with reference to exemplary embodiments. For clarity, the attached figures serve. It shows

1 shows a longitudinal section through an exemplary knobbed tube,

Fig. 2 is an external view of the tube of FIG. 1,

3 shows a cross section of the tube from FIG. 1 and 2,

4 shows an embodiment with strands extending on the outer lateral surface nubs,

5 is an external view of a tube with helically arranged knobs,

6 is an external view of a tube with radially and rosette-shaped nubs,

Fig. 7 is a series of exemplary studded shapes.

Fig. 1 shows a longitudinal section through an exemplary studded tube. The tube shown here has an inner circumferential surface 1 and an outer lateral surface 2. This is occupied by a plurality of nubs 3, between which cavities 4 are located. The inner circumferential surface 1 is smooth throughout and has no formations. The nubs 3 can be formed both macroscopically and microscopically be. They form on the outside of the tube by their shape an area with high and deep, or convex and concave shaped areas. The outside of the pipe can consist of the base material of the pipe wall in a first embodiment. In a further embodiment, a pipe which is in itself smooth is provided with a nub surface applied in a layer-like manner on its lateral surface. The nubs can be made in the latter case of a material different from the material of the pipe wall.

The knobs may be oriented differently with respect to the outer circumferential surface. In the in Fig. 2 embodiment, all longitudinal axes of the studs are oriented perpendicular to the pipe wall with respect to the longitudinal direction of the tube, wherein the studs are arranged substantially parallel to each other. The nubs have in this example Noppenköpfe 5 in a rounded shape.

The knobs can be distributed in different ways on the outer circumferential surface. In the case of FIG. 1 and FIG. In the embodiment shown in FIG. 2, the nubs are arranged in rows of two each extending along the longitudinal axis of the pipe such that, in cross-section, a line shown in FIG. 3 cross figure results. Such an arrangement of the nubs is recommended when the tube is to be flowed through by a surrounding medium in the longitudinal direction. But this knob arrangement is also advantageous for a pipe that is to be installed in a solid backfilling, for example in the soil.

As shown in FIG. 4, the nubs arranged in a linear manner can thus be combined to form a nip strand 4a running substantially in the tube longitudinal direction.

Fig. 5 shows a nub arrangement in the form of a double helix 6. In this embodiment, the nubs are radially from the outer surface of the tube from. The pitch of the double helix, ie their pitch, depends on the intended conditions of use of the pipe. Such a doping Pelhelix is advantageous if a flowing outside of the tube medium is deflected with a flow direction perpendicular to the tube longitudinal axis and partially guided along the pipe, for example, to intensify thermal contact.

Fig. 6 shows a knob arrangement in a rosette shape. Each individual rosette 7 consists of radially outgoing from the outer surface, distributed around the pipe circumference knobs. The nubs of a rosette are parallel to the next adjacent knob of the next rosette. Such an embodiment is particularly well suited for heat transfer with an outer, in the direction of the tube longitudinal axis flowing medium or with a surrounding the pipe landfill, for example, the soil.

Fig. 7 shows some exemplary stud shapes. In one of the preceding embodiments, a rounded knobhead 5 has already been mentioned. Such a knobbed head is expediently combined with a cylindrical knob shaft 8. The cylindrical nub shaft can also be combined with a pointed, in particular conical, nub head 9. Such a sharpened knobbed shape allows piercing or skewing of mat-shaped sheaths to isolate or even attach heat-conducting materials to the outside of the tube. The nubs formed in this way are rod-shaped or finger-shaped from the outside of the tube and extend into the environment, with an intense thermal contact can be achieved.

The cylindrical nub shaft 8 can also have a greatly shortened or vanishing length. In conjunction with the rounded knobbed head 5, a rounded, strongly shortened, in the tendency hemispherical, knob 8a is formed.

In general, a large number of other prismatic shapes with different base and top surfaces are possible for the nub shaft. Fig. 7 shows an example of a nub with a triangular nub shaft 10 and a pyramidal, pointed knobbed head 11. Instead of the triangular prism is of course a prism with any number of corners, in particular a four- or hexagonal prism possible. The hexagonal shape has the advantage that the knob can be grasped with a wrench or a suitable pliers and tightened on the tube outside in corresponding threaded holes or can be removed from these.

Of course, the nub shaft can also be designed as a conical or truncated cone-shaped nub shaft 12 or a pyramid-shaped or pyramid-truncated nub shaft 13. In the examples shown here, the knobbed head is not formed, wherein the knobbed shaft each terminates with a plane surface. Such conical or pointed, reinforced at the base knobbed shapes are particularly useful when the nubs against shear and bending forces resistant form is required.

As a material for the knobs, both rigid and flexible materials are available for given nip thicknesses and lengths. Suitable rigid materials are, in particular, the metallic materials customary in pipeline construction. This can be mainly steel materials, but also zinc, copper or lead alloys, but also glass materials. Flexible materials can be used in the form of rubber, plastics or composite materials, in particular coated metal wires or other fiber materials.

The exemplary embodiments shown here can be supplemented by other embodiments within the scope of expert practice, without departing from the scope of the basic concept according to the invention. Further embodiments emerge in particular from the subclaims. LIST OF REFERENCE NUMBERS

1 inner lateral surface

2 outer circumferential surface

3 pimples

4 cavity

4a knobbed strand

5 knobbed head, rounded

6 double helix

7 rosette

8 Studded, cylindrical 8a knob, hemispherical

9 knobbed head

10 knob stem, triangular

11 knobbed head, pyramidal

12 knobbed stem, frustoconical

13 Studded stem, truncated pyramid

Claims

claims

1. tube having a modified by a surface profile outer surface (2), characterized in that the surface profile of the outer circumferential surface outgoing on the

Outer shell surface distributed nubs (3).

2. Pipe according to claim 1, characterized in that an inner circumferential surface (1) has a smooth surface.

3. Pipe according to one of claims 1 or 2, characterized in that the nubs (3) extend with respect to the longitudinal direction of the tube substantially parallel to each other.

4. Pipe according to one of claims 1 to 3, characterized in that the nubs (3) are oriented substantially radially to the outer circumferential surface (2).

5. Pipe according to one of claims 1 to 3, characterized in that the knobs (3) are oriented at an angle to the outer circumferential surface.

6. Pipe according to one of the preceding claims, characterized in that the nubs (3) are mutually uniformly spaced.

7. Pipe according to one of the preceding claims, characterized in that the knobs (3) are arranged in a regular, the outer circumferential surface at least partially covering pattern.

8. Pipe according to one of claims 1 to 7, characterized in that the knobs (3) are arranged in an irregular, the outer circumferential surface at least partially covering pattern.

9. Pipe according to one of the preceding claims, characterized in that the nubs (3) have a prismatic shaped nub shaft (8, 10).

10. Pipe according to one of claims 1 to 8, characterized in that the nubs (3) have a conical or pyramidal nub shaft (12, 13).

11. Pipe according to one of the preceding claims, characterized in that the knobs (3) have a flattened knobbed head (14).

12. Pipe according to one of claims 1 to 9, characterized in that the nubs (3) have a pointed nub head (9, 11).

13. Pipe according to one of claims 1 to 9, characterized in that the nubs (3) have a rounded nub head (5).

14. Pipe according to one of claims 1 to 8, characterized in that the nubs (3) are formed hemispherical.