HEATING DEVICE EXHAUST PIPE ARRANGEMENT WITH INTEGRATED MUFFLER AND METHOD FOR PRODUCING SAME

Abstract

Provided is a heating device exhaust gas arrangement with an integrated sound suppressor, having: a rigid exhaust gas pipe (1) which is made by bending and longitudinally welding a perforated metal sheet and which has an un-perforated, curved first pipe section (2), an un-perforated second pipe section (3) and, formed integrally with the first pipe section (2) and the second pipe section (3), a perforated sound suppressor section (4) between the first pipe section (2) and the second pipe section (3), and a sound suppressor housing (5) which externally covers the perforated sound suppressor section (4) and which is arranged such that the first pipe section (2) and the second pipe section (3) both extend at least predominantly outside the sound suppressor housing (5).

Claims

1. A heating device exhaust pipe arrangement with an integrated muffler, having: a flexurally stiff exhaust pipe, which is manufactured from a perforated metal sheet by round bending and longitudinal welding and has an unperforated curved first pipe section, an unperforated second pipe section and, formed integrally with the first pipe section and the second pipe section, a perforated muffler section between the first pipe section and the second pipe section, and a muffler housing, which covers the exterior of the perforated muffler section and is arranged in such a way that the first pipe section and the second pipe section each extend at least predominantly outside the muffler housing.

2. The heating device exhaust pipe arrangement as claimed in claim 1, wherein the perforated muffler section extends over at most 40% of the total length of the exhaust pipe.

3. The heating device exhaust pipe arrangement as claimed in claim 1 , wherein at least one of the curved first pipe section and the second pipe section has a length of at least 80% of the length of the perforated muffler section.

4. The heating device exhaust pipe arrangement as claimed in claim 1, wherein the curved first pipe section and the second pipe section each have a length of at least 50% of the length of the perforated muffler section.

5. The heating device exhaust pipe arrangement as claimed in claim 1, wherein at least the curved first pipe section has a curvature >90°.

6. The heating device exhaust pipe arrangement as claimed in claim 1, wherein the muffler housing is welded to the outside of the exhaust pipe.

7. The heating device exhaust pipe arrangement as claimed in claim 1, wherein the muffler housing has two half shells of identical design.

8. The heating device exhaust pipe arrangement as claimed in claim 1, wherein a noise-absorbing insulating material is arranged between the inside of the muffler housing and the outside of the perforated muffler section.

9. The heating device exhaust pipe arrangement as claimed in claim 8, wherein the insulating material comprises at least one of mineral wool and glass wool.

10. The heating device exhaust pipe arrangement as claimed in claim 1, characterized in that the exhaust pipe is manufactured from a temperature-stable steel sheet.

11. A mobile fuel-operated heating device having a heating device exhaust pipe arrangement as claimed in claim 1.

12. A method for producing a heating device exhaust pipe arrangement with an integrated muffler, comprising the following steps: forming a flexurally stiff pipe having a first unperforated pipe section, a second unperforated pipe section and a perforated muffler section arranged therebetween by round bending and longitudinal welding of a regionally perforated metal sheet; inelastically deforming at least of the first unperforated pipe section to form a flexurally stiff exhaust pipe having an unperforated curved first pipe section, an unperforated second pipe section and a perforated muffler section situated therebetween, securing a muffler housing in the region of the perforated muffler section in such a way that the unperforated curved first pipe section and the unperforated second pipe section extend at least predominantly outside the muffler housing.

13. The method as claimed in claim 12, comprising the following step: welding the muffler housing to the exhaust pipe.

14. The method as claimed in claim 12, comprising the following step: introducing a sound-absorbing insulating material between an inside of the muffler housing and an outside of the perforated muffler section.

15. The heating device exhaust pipe arrangement as claimed in claim 1, wherein the perforated muffler section extends over at most 35% of the total length of the exhaust pipe.

16. The heating device exhaust pipe arrangement as claimed in claim 1, wherein at least the curved first pipe section has a curvature >120°.

Description

[0026] Further advantages and developments will become apparent from the following description of an illustrative embodiment with reference to the attached drawings.

[0027] FIG. 1 is a schematic illustration of a regionally perforated metal sheet of the kind used in the method according to the invention.

[0028] FIG. 2 is a schematic illustration of a flexurally stiff metal pipe, which is manufactured from the perforated metal sheet in FIG. 1 by round bending and longitudinal welding and has a first unperforated pipe section, a second unperforated pipe section and a perforated muffler section arranged therebetween.

[0029] FIG. 3 is a schematic illustration of a flexurally stiff exhaust pipe according to the embodiment.

[0030] FIG. 4 is a schematic illustration of the flexurally stiff exhaust pipe with a half shell of a muffler housing.

[0031] FIG. 5 is a schematic illustration of the exhaust pipe with a muffler housing secured thereon.

[0032] FIG. 6 is a schematic section through a heating device exhaust pipe arrangement with an integrated muffler according to the embodiment.

[0033] FIG. 7 is a schematic perspective illustration of the heating device exhaust pipe arrangement.

[0034] An embodiment of the heating device exhaust pipe arrangement 100 with integrated muffler is described below with reference to FIG. 1 to FIG. 7.

[0035] The heating device exhaust pipe arrangement 100 according to the embodiment is designed specifically for a mobile fuel-operated heating device, in particular for a vehicle heating device of the kind typically used in a parking heater or auxiliary heater, for example.

[0036] The heating device exhaust pipe arrangement 100 with integrated muffler has an inflexible exhaust pipe 1, as illustrated in FIG. 3. The exhaust pipe 1 is formed from metal, in particular from sheet steel consisting of a temperature-stable steel grade in the specifically illustrated embodiment. The exhaust pipe 1 has a curved first pipe section 2, a curved second pipe section 3 and a muffler section 4 formed between the curved first pipe section 2 and the curved second pipe section 3. In this case, the muffler section 4 is formed integrally with the curved first pipe section 2 and the curved second pipe section 3 from the metal sheet. In the muffler section 4, the wall of the exhaust pipe 1 is perforated, whereas the curved first pipe section 2 and the curved second pipe section 3 are unperforated, i.e. are formed with a continuous pipe wall. In the perforated muffler section 4, the wall of the exhaust pipe 1 is provided with a multiplicity of holes, which connect the inside of the muffler section 4 to the outside of the muffler section 4.

[0037] The unperforated curved first pipe section 2 and the unperforated curved second pipe section 3 each extend over a pipe length (measured as the flow path formed in the center of the pipe) which is at least 50% of the length of the perforated muffler section 4. In the specifically illustrated illustrative embodiment, the unperforated curved first pipe section 3 extends over a length which corresponds approximately to the length of the muffler section, and the unperforated curved second pipe section 3 thus extends over more than 80% of the length of the muffler section 4. Together, the unperforated curved first pipe section 2 and the unperforated curved second pipe section form a larger proportion of the length of the exhaust pipe 1 than the perforated muffler section 4.

[0038] In the embodiment illustrated, the unperforated curved second pipe section 3 is provided with a curvature of about 90°, for example, and the unperforated curved first pipe section 2 is provided with a significantly larger curvature, in particular a curvature >120°, or even a curvature of more than 160° in the specifically illustrated illustrative embodiment. In contrast, the perforated muffler section 4 extends at least substantially in a linear manner, being therefore of uncurved design, in the embodiment.

[0039] The exhaust pipe 1 having the unperforated curved first pipe section 2, the perforated muffler section 4 and the unperforated curved second pipe section 3 is embodied so as to be flexurally stiff, and therefore it is self-supporting, i.e. does not deform if it is secured only at one or a few points, for example. The exhaust pipe 1 is formed by round bending and longitudinal welding of a flat metal sheet 10, which has an unperforated first section 11, an unperforated second section 12 and a perforated section 13 situated therebetween, of the kind illustrated schematically in FIG. 1, for example. In particular, the holes in the perforated section 13 can be produced in the metal sheet 10 by punching, allowing particularly low-cost manufacture. The flexurally stiff pipe 20 produced by round bending and longitudinal welding is illustrated schematically in FIG. 2. As illustrated schematically in FIG. 2, the flexurally stiff pipe 20 has a weld seam 25, which extends in the longitudinal direction of the pipe 20 and which is illustrated in dashed lines in FIG. 2. It should be noted that FIG. 1 and FIG. 2 are only schematic illustrations, and the length of the unperforated sections 11 and 12 and of the perforated section 13 of the metal sheet 10 do not correspond fully to the respective lengths of the exhaust pipe 1 illustrated in FIG. 3 to FIG. 7, owing to the schematic illustration. As can be seen in FIG. 2, the flexurally stiff pipe 20 formed has an unperforated first pipe section 21, an unperforated second pipe section 22 and the muffler section 4 situated therebetween.

[0040] The flexurally stiff exhaust pipe 1 illustrated in FIG. 3 is formed by inelastic deforming of the flexurally stiff pipe 2. Here, the unperforated curved first pipe section 2 and the unperforated curved second pipe section 3 are formed by bending the unperforated pipe sections 21 and 22 using a conventional pipe bending apparatus. To produce the flexurally stiff exhaust pipe 1, the free end of the unperforated curved first pipe section 2 and/or the free end of the unperforated curved second pipe section 3 can also, in particular, be cut to the required length.

[0041] To form the heating device exhaust pipe arrangement 100 according to the embodiment, the flexurally stiff exhaust pipe 1 is provided with a muffler housing 5. In the embodiment, the muffler housing 5 has two half shells 5a, 5b of identical design to one another, which allows particularly low-cost production. In the embodiment, the muffler housing 5 is also formed from sheet metal, in particular from sheet steel. In this case, it is possible, in particular, for the half shells 5a, 5b of the muffler housing 5 to be formed from the metal sheet by deforming. The half shells 5a, 5b of the muffler housing 5 are arranged on the flexurally stiff exhaust pipe 1 in such a way that the muffler housing 5 covers the perforated muffler section 4. In this case, the muffler housing 5 surrounds the entire outer circumference of the muffler section 4, and therefore an interspace is formed between the outside of the perforated muffler section 4 and the inside of the muffler housing 5, as can be seen especially in the schematic sectional illustration in FIG. 6. Arranged in the interspace is a noise-absorbing insulating material 6, which, in particular, is formed by mineral wool in the embodiment. As an alternative or in addition, it is also possible, in particular, to use glass wool as an insulating material. However, it is also possible to use other temperature-stable and environmentally stable fiber materials.

[0042] The muffler housing 5 is connected to the outside of the flexurally stiff exhaust pipe 1 by welding. The muffler housing 5 is dimensioned in such a way that both the unperforated curved first pipe section 2 and the unperforated curved second pipe section 3 extend predominantly outside the muffler housing 5. The unperforated curved first pipe section 2 and the unperforated curved second pipe section 3 thus not only form connection pieces, protruding from the muffler housing 5, for partial lengths of an exhaust pipe but each themselves form partial lengths of the exhaust pipe. The muffler housing 5 is welded to the muffler section 4 or to regions of the unperforated curved first pipe section 2 and/or of the unperforated curved second pipe section 3 which directly adjoin said muffler section. Here, it is possible, in particular, for the welded joint between the muffler housing 5 and the exhaust pipe 1 to be formed in a simple and low-cost way by spot welding.

[0043] In the embodiment, the heating device exhaust pipe arrangement 100 with an integrated muffler furthermore has a bracket 7 for securing the heating device exhaust pipe arrangement 100, as can be seen in FIG. 6 and FIG. 7. The bracket 7 is likewise made from sheet metal and is connected to the muffler housing 5 by welding. By virtue of the flexurally stiff design of the exhaust pipe 1, the heating device exhaust pipe arrangement can be secured exclusively by means of the bracket 7, for example, and the heating device exhaust pipe arrangement 100 is held in a self-supporting manner, in particular preventing the unperforated curved first pipe section 2 or the unperforated curved second pipe section 3 from moving relative to the integrated muffler formed by the muffler section 4 and the muffler housing 5. As a result, the welded joint between the exhaust pipe 1 and the muffler housing 5 is not acted upon by high forces, and therefore this joint is very stable and durable.

[0044] Since the muffler section 4 is designed as part of the exhaust pipe 1, the exhaust pipe 1 can be designed to be curved directly adjoining the muffler housing 5, thus allowing a significantly more compact configuration as compared with separate formation of a muffler and partial exhaust pipe lengths secured thereon, e.g. by means of connection pieces.

[0045] In a method for producing the heating device exhaust pipe arrangement 100 according to the embodiment, a flexurally stiff pipe 20 having a first unperforated pipe section 21, a second unperforated pipe section 22 and a perforated muffler section 4 arranged therebetween, as illustrated schematically in FIG. 2, is formed by round bending and longitudinal welding of a regionally perforated metal sheet 10, which is illustrated schematically in FIG. 1.

[0046] The first unperforated pipe section 21 and the second unperforated pipe section 22 are then deformed inelastically, this being carried out in a conventional pipe bending apparatus, for example. In this way, the flexurally stiff exhaust pipe 1 with the unperforated curved first pipe section 2, the unperforated curved second pipe section 3 and the perforated muffler section 4 situated therebetween is formed, being illustrated schematically in FIG. 3.

[0047] The muffler housing 5 is then secured on the exhaust pipe 1 in the region of the perforated muffler section 4 in such a way that the unperforated curved first pipe section 2 and the unperforated curved second pipe section 3 extend at least predominantly outside the muffler housing 5. In the illustrative embodiment, securing is accomplished, in particular, by welding, in particular by spot welding. Before or during the securing of the muffler housing 5, the sound-absorbing insulating material 6 is arranged between the inside of the muffler housing 5 and the outside of the perforated muffler section 4. The bracket 7 can be connected to one of the two half shells 5a, 5b even before the muffler housing 5 is secured, for example, or, alternatively, can be secured only after the muffler housing 5 has been secured on the flexurally stiff exhaust pipe 1. The securing of the bracket 7 can also preferably be accomplished by spot welding.