DE29815970U1 - Chimney pipe - Google Patents

Description

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EUROPEAN PATENT AND TRADEMARK ATTORNEYS

Application for registration of a utility model

(31) Priority Application Number:

(32) Priority Date:

(33) Priority Country:

Our reference: T173DE7 B/mü

(54) Title:

Chimney pipe

(71) Applicant:

Technaflon AG Konstanzer Strasse

8274 Tägerwilen Switzerland

(73) Inventor:

1. Dieter Baechle

2. Horst Wish

c/o both Technaflon AG, Konstanzer Straße 7 8274 Tägerwilen I Switzerland

(74) Representative / Agent:

Dipl.-Ing. Gerhard F. Hiebsch

Dipl.-Ing. Dr. oec. Niels Behrmann M.B.A. (NY)

Heinrich-Weber-Platz

78224 Singen

T173DE7 " - 1 *:

CHIMNEY PIPE

The present invention relates to a chimney pipe according to the preamble of claim 1.

Chimney pipes, especially those for use in a condensation or wet chimney, are, due to their design, subject to particular stresses, both from the condensate from the smoke or exhaust gases condensing on their inner surface, and from mechanical stresses.

Traditionally, such chimney pipes are made of corrosion-resistant steel, although this material is not only complex to process, but also has cost disadvantages.

For several years now, plastic chimney pipes made from PVDF (polyvinylidene chloride) have been sold under the "TECHNAFLON" brand. Not only does this tough and highly temperature-resistant material reach the critical limit of 160° for exhaust gas temperatures, it is also sufficiently resistant to aggressive condensate, which occurs in wet chimneys in particular. In addition, the material achieves fire class VO. This has enabled such plastic chimney pipes to establish themselves as a serious alternative to the stainless steel chimney pipes described above.

However, conventional hollow-cylindrical PVDF chimney pipes also have the disadvantage of expensive materials and thus high production costs, so that from a purely cost perspective this solution is only limitedly competitive with stainless steel.

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The object of the present invention is therefore to improve generic plastic chimney pipes, in particular for use in a wet chimney, in such a way that, with largely unchanged stability and in no way impaired operating (condensation) properties, more efficient production is possible through improved material utilization and thus, as a result, also more cost-effective production.

The problem is solved by the rigid chimney pipe with the features of claim 1.

In an advantageous manner according to the invention, this chimney pipe has a surface profile formed only on the inner surface, whereby the stability, for example the kink resistance, of such a pipe is practically unchanged compared to a hollow cylindrical pipe with a smooth inner surface with an inner surface corresponding to the maximum thickness of the profile. In contrast, the profiling of the inner surface, which is preferably achieved by a suitable tool design of the extrusion tool for producing the pipe, ensures both a material saving compared to the solid pipe (i.e. the pipe with a continuously smooth inner surface) and an increase in the surface area that comes into contact with the exhaust gas flow in the chimney, thus increasing the effective condensation surface and thus improving the efficiency of the chimney.

Pipes that are designed to be elongated, bent or angled as intended, but are never intended to change an extension direction or a bending or buckling direction, and therefore have a minimum rigidity necessary to achieve this state, are to be regarded as "rigid" in the sense of the invention.

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While it is particularly preferred within the scope of the invention to use PVDF as the material for the realization of the chimney pipe, other plastics suitable for the production of an intended chimney pipe are also included, such as PET or PETP (polyethylene terephthalate).

Further advantageous developments of the invention are described in the subclaims.

It is therefore particularly preferred, for example by appropriately designing the extrusion tool, to provide the profiling and thus the cross-sectional contour of the inner surface with the selected profile pattern continuously and regularly, whereby this is preferably wave-shaped, toothed or half-wave-shaped.

More preferably, the profiling can be defined by radii or circular arcs, which, depending on the shape of the wave structure, have their origin inside or outside the tube.

According to alternative embodiments, it is also possible to realize the profiling by means of a plurality of projections that extend from an otherwise smooth inner surface of the chimney pipe. These projections are particularly preferably T-shaped in cross section in order to realize the largest possible condensation surface with minimized flow resistance for the exhaust gas.

The result is a chimney pipe which, while still providing sufficient mechanical stability, allows for a significantly reduced use of materials for manufacturing and thus a much more efficient production, and also achieves additional advantages in terms of efficiency by effectively increasing the condensation surface in the interior of the chimney pipe.

T173DE7 -4^iI

Further advantages, features and details of the invention emerge from the following description of preferred embodiments and from the drawings; these show in

Fig. 1: a sectional view through a

Chimney pipe according to a first preferred embodiment of the invention with a smooth outer casing and a toothed inner profile;

Fig. 2: a preparatory sectional view

to illustrate the geometry of a chimney pipe according to a second, preferred embodiment;

Fig. 3: a detailed view of circular-section-shaped grooves as profiling on the inner surface according to the arrangement in Fig. 2 and

Fig. 4: another alternative embodiment with a profiling of the chimney pipe realized by projections extending from the inner surface.

Fig. 1 shows a cross-sectional view of a chimney pipe 10 made from PVDF by means of extrusion and intended for use in wet or condensation chimneys, the smooth cylindrical outer surface (shell surface) 12 of which determines an outer diameter of mm in the illustrated embodiment. An inner surface of the pipe 10 has the profile 14 shown in Fig. 1, which is serrated in cross section and which, in the respective recesses of the serration, reduces a maximum thickness of the chimney pipe 10 from 2 mm to a minimum.

T173DE7 - 5

times 1.2 mm and thus ensures that in the direction of extension (longitudinal direction) of the pipe, this has regularly arranged, elongated recesses (grooves) 16 along its inner surface.

The design shown in Fig. 1 allows the material required for extruding a pipe to be reduced by 10 to 40%, in practice around 30%, compared to a solid pipe with a constant wall thickness of 2 mm (and thus an inner surface that is smooth like the outer surface). Accordingly, the surface area that is important for condensation increases by around 30% compared to a smooth inner surface, thus increasing the efficiency of a condensation or wet chimney constructed with the pipe shown.

The concrete geometric structure of a chimney according to a further preferred embodiment is now described with reference to Figs. 2 and 3. Fig. 2 shows a cross section through the chimney pipe, but here the profiling is only indicated by the rays running at a distance of 7.5° in one quadrant. The pipe according to this embodiment also has an external diameter D _a of 125 mm and a clear internal diameter D ₁ of 121 mm defined by the distance between two maximum profile elevations.

Fig. 3 shows in detail how the profiling in the pipe of Fig. 3 is realized. The reference number 10 describes the pipe wall of the outer diameter D _a , in which circular arcs or circular sections (each based on the cross-sectional view of Fig. 3) are cut out at a distance of 2 x α, ie 15°. To be more precise, such a circular arc has a radius Rl of 16 mm in the embodiment shown, so that adjacent, non-overlapping circular arc-shaped recesses are created. The origin of the radius (circular arc) for the recess according to Rl is inside the pipe.

T173DE7 - 6 &Aacgr;

In addition, the resulting shape, as shown by the arc along radius R2, is ground using a circular arc of radius R2 running around a center point outside the pipe (here: R2 = 18 mm), so that a continuous, largely step-free wave shape is created. The center of this circle lies on the bisector of the 15° angle 2 α, i.e. it runs between the two inner circular arcs Rl.

Due to the profiling shown, a maximum wall thickness Dl of 2 mm in the illustrated embodiment at the deepest point of each circular recess is reduced to a minimum wall thickness of 1.2 mm.

Fig. 4 shows another alternative embodiment of the present invention.

As is possible in particular through a corresponding - somewhat more complex - design of the extrusion tool, projections 20 are formed here at regular intervals along the (otherwise smooth) inner surface of the tube, in one piece with the wall 22, which have the cross-sectional T-shape shown in Fig. 4 and extend along the inner circumferential direction over a width a. It is particularly suitable to make the width a wider than the thickness of a connecting web 24 to the wall 22, so that the largest possible effective surface for condensation is achieved.

In the illustrated embodiment of Fig. 4, two adjacent projections 20 are spaced apart by a distance b between their respective ends, wherein it is particularly preferred to make the distance b equal to the width a of the projections, so that an optimization of the condensation surface is achieved while at the same time minimizing a flow resistance in the pipe caused by the profiling.

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The present invention is not limited to the embodiments described; it is thus possible in particular to design the pipes in any other internal and external diameters (preferably adapted to standard sizes intended for chimneys), for example with external diameters of 75 or 160 mm, and in addition to elongated, straight chimney pipes, it is also possible to design predetermined angle or curved pieces in the manner according to the invention.

Furthermore, the present invention is not limited to the material used, PVDF, but any other plastics, such as PET, could be suitable for implementing the invention, depending on the requirements profile for the pipe in the chimney system.

As a result, the measures according to the invention result in a significantly improved chimney pipe, which combines a significant reduction in manufacturing costs with improved operating properties, without having to accept disadvantages in terms of buckling resistance or other stability parameters.

Claims (9)

EXPECTATIONS 1. Chimney pipe, in particular for use in a wet chimney, made of a plastic material forming a rigid pipe body (10), in particular PVDF or PETP, with a smooth, cylindrical outer surface (12), marked by a profiling (14) formed on an inner surface of the chimney pipe, which offers a larger surface area than a smooth inner surface and is continuously formed in cross-section, at least in sections, relative to a circumferential direction of the chimney pipe. 2. Chimney pipe according to claim 1, characterized in that the inner surface in cross section, relative to a circumferential direction, is continuously and regularly profiled. 3. Chimney pipe according to claim 1 or 2, characterized in that the profiling is wave-shaped and designed in such a way that a profile shape can be determined cross-sectionally through a plurality of adjacent cutouts defined by circular arcs of the same radius (Rl) from a smooth inner surface of a predetermined wall thickness (Dl). 4. Chimney pipe according to claim 3, characterized in that the circular arcs have an origin which lies inside or outside the chimney pipe. 5. Chimney pipe according to claim 3 or 4, characterized in that the radius, based on an outer diameter of the chimney pipe, has a ratio of 1:5 to 1:10. T173DE7 - 9 ~-: 6. Chimney pipe according to one of claims 1 to 5, characterized in that a maximum profile depth of the profiling in the radial direction, based on a maximum wall thickness, is 20 to 60% of this, preferably 30 to 45% of this. 7. Chimney pipe according to one of claims 1 to 6, characterized in that the profiling has a tooth or half-wave shape. 8. Chimney pipe according to one of claims 1 to 6, characterized in that the profiling has a plurality of projections (20) arranged at regular intervals in the circumferential direction and preferably T-shaped in cross section. 9. Chimney pipe according to claim 8, characterized in that a width (a) of a projection in the circumferential direction corresponds to the distance (b) to an adjacent, identical projection.