Freestanding steel chimney

Abstract

Freestanding steel chimney (1), comprising: - a self-supporting outer tube made of steel (2), - an inner tube (3) arranged in and connected to the outer tube (2), characterized in that the outer tube (2) has an n-sided cross-section, wherein 6 ≤ n ≤ 12.

Description

[0001] The invention relates to a free-standing steel chimney, comprising a self-supporting outer pipe made of steel and an inner pipe arranged in the outer pipe and connected thereto.

[0002] Such steel chimneys are designed and constructed according to the standards Eurocode 3 EN 1993-1-6 and EN 1993-3-2.

[0003] The operation of a heat generator that relies on the combustion of a fuel produces exhaust gases or flue gases that must be removed through a chimney. Chimneys can be made of different materials and can be single-walled or double-walled. A conventional double-walled steel chimney consists of an outer steel pipe containing an inner pipe. Double-walled chimneys are characterized by better draft.

[0004] Currently, freestanding steel chimneys have a circular cross-section. High-output heat generators require tall chimneys. Chimneys are designed with the forces and loads encountered during operation, especially wind, in mind. A taller chimney with a circular cross-section requires greater wall thickness.

[0005] The invention is therefore based on the object of providing a free-standing steel chimney that can be manufactured more cost-effectively.

[0006] To solve this problem, a free-standing steel chimney with the features of claim 1 is provided.

[0007] The steel chimney according to the invention is characterized in that the outer pipe has an n-cornered cross-section, where 6 ≤ n ≤ 12.

[0008] The invention is based on the finding that a steel chimney with a rectangular cross-section that exceeds a certain height offers structural advantages compared to an otherwise identical steel chimney with a circular cross-section. Due to the rectangular cross-section, the wall thickness of the outer pipe can be thinner in certain configurations compared to a steel chimney of the same height with a circular cross-section. Depending on the load assumptions and other boundary conditions, a rectangular cross-section can exhibit greater stability against wind loads and thus be advantageous from a structural point of view. The material savings achieved by the thinner wall thickness reduce the manufacturing costs of the steel chimney.A further advantage is that the steel chimney according to the invention can be designed to be free-standing, whereas a chimney of the same height with a round cross-section may require a vibration damper depending on the static boundary conditions, which increases the costs.

[0009] In the context of the invention, it is preferred that n = 8 and the steel chimney thus has an octagonal cross-section.

[0010] The outer tube is preferably made of structural steel S355J2C+N. This material is characterized by good formability, which is necessary when bending the steel profile for the outer tube.

[0011] The outer pipe can be provided with a zinc coating. Preferably, the outer pipe is hot-dip galvanized or, more preferably, hot-dip galvanized according to DIN EN 1461 (in the version valid on the date of application). The steel chimney according to the invention is therefore corrosion-resistant and durable.

[0012] The steel chimney according to the invention can be single-flue, double-flue or multi-flue.

[0013] For connection to a subsurface or foundation, the outer tube preferably has a base flange. The base flange can be designed as a plate with through holes for screws.

[0014] Within the scope of the invention, it is preferred that the steel chimney has several vertically spaced, substantially horizontally arranged brackets between the outer pipe and the inner pipe, connecting the outer pipe to the inner pipe. These brackets center the outer pipe with the inner pipe and ensure the stability of the steel chimney.

[0015] The inner pipe is preferably made of stainless CrNiMo steel (V4A). Stainless steel is permanently resistant to exhaust gases and flue gases.

[0016] The inner pipe may be insulated on its outside. This insulation prevents rapid cooling of the rising flue gases and improves the efficiency of the steel chimney.

[0017] The invention is explained below using an exemplary embodiment with reference to the drawings. The drawings are schematic representations and show: Fig. 1 is a side view of a freestanding steel chimney according to the invention; Fig. 2 a sectional view of the Fig. 1 shown steel chimney; Fig. 3 a relative to the view of Fig. 2 sectioned view rotated by 90°; and Fig. 4 a horizontal section view of the steel chimney.

[0018] An example of the steel chimney is shown on the Fig. 1 to 4. This shows Fig. 1 a side view, Fig. 2 a sectioned view, Fig. 3 a view rotated by 90° and Fig. 4 shows a horizontal section. The steel chimney is designed and constructed according to Eurocode 3 EN 1993-1-6 and EN 1993-3-2.

[0019] The single-flue steel chimney 1 is freestanding and comprises an outer pipe 2, inside which an inner pipe 3 is arranged. In other designs, the steel chimney can also be designed with two or more flues. At the lower end of the outer pipe 2 is a base flange (not shown), which is attached to a foundation 4. In the sectional views of the Fig. 2 and Fig. 3 shows that an annular space 5 is formed between the inner tube 3 and the outer tube 2. The inner tube 3 and the outer tube 2 are connected to each other and centered relative to each other via a plurality of substantially horizontally extending brackets 6, which are arranged vertically spaced from each other.

[0020] The Fig.The horizontal section shown in Figure 4 shows that the outer pipe has an octagonal cross-section. The octagonal cross-section is merely an example; alternatively, the cross-section of the outer pipe could also be hexagonal or dodecagonal. The angular shape increases the stability of the steel chimney 1 compared to a chimney of the same wall thickness with a circular cross-section. The steel chimney 1 does not require any bracing, nor is a vibration damper required.

[0021] In the illustrated embodiment, the outer pipe 2 is made of structural steel S355J2C+N. The outer pipe is hot-dip galvanized inside and out (according to DIN EN 1461). The inner pipe 3 is made of stainless CrNiMo steel (V4A). On its outside, the inner pipe 3 is surrounded by insulation 7. The steel chimney 1 comprises a combustion connection 8 designed as a flange or plug-in connection and a cleaning connection 9 located underneath. A condensate drain 10 with rear ventilation is provided near its lower end. List of reference symbols 1 steel chimney 2 outer tube 3 inner tube 4 Foundation 5 Annular space 6 Bracket 7 Insulation 8 Combustion connection 9 Cleaning connection 10 Condensate drain

Claims

[1] Freestanding steel chimney (1), comprising: - a self-supporting outer tube made of steel (2), - an inner tube (3) arranged in the outer tube (2) and connected thereto, characterized by that the outer tube (2) has an n-cornered cross-section, where 6 ≤ n ≤ 12. [2] Steel chimney according to claim 1, wherein the outer pipe (2) is made of structural steel S355J2C+N. [3] Steel chimney according to claim 1 or 2, wherein the outer pipe (2) is galvanized, hot-dip galvanized or hot-dip galvanized. [4] Steel chimney according to one of the preceding claims, wherein the outer pipe (2) has a base flange. [5] Steel chimney according to one of the preceding claims, wherein between the outer pipe (2) and the inner pipe (3) there are arranged a plurality of vertically spaced apart, substantially horizontally arranged brackets (6) connecting and centering the outer pipe (2) to the inner pipe (3). [6] Steel chimney according to one of the preceding claims, wherein the inner pipe (3) is made of stainless CrNiMo steel (V4A). [7] Steel chimney according to one of the preceding claims, wherein the inner pipe (3) has an insulation (7) on its outer side.

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