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(11) | EP 0 156 228 B1 |
| (12) | EUROPEAN PATENT SPECIFICATION |
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| (54) |
Water heater construction and method of manufacture Wassererhitzerkonstruktion und Verfahren zur Herstellung Construction d'un réchauffeur d'eau et procédé de fabrication |
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| Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). |
[0001] The invention relates to a water heater tank assembly and a method of its manufacture as outlined in the preamble of the independent claims 1 and 5.
[0002] A water heater tank assembly of this type is disclosed in US-A-2 363 980. The known tank assembly is a tank for water storage heaters having a ceramic enamelled interior surface. The tank is described to have a head showing a knuckle curvature and skirt extending beyond the knuckel radius essentially parallel to the shell. In order to prevent any cracking or otherwise damaging of the enamel during the welding procedure of the head to the shell, the skirt of the head is provided with a plurality of circumferentially spaced grooves extending about a half of the thickness of the material into the skirt. Flue tubes and their connecting to the head and bottom members are not shown.
[0003] FR-A-1 301 484 describes a heat exchanger having tubes welded to tube plates. In order to prevent the rupture of the welded connection due to different thermal expansions between the tube and their support during use, an extension member is arranged between each tube and the respective tube plate. The extension member is, at its one end, connected to the tube plate and, at its other end, welded to the tube. The publication does not disclose any indication as to how lined tubes are to be connected to head and bottom members also lined with a lining which tends to crack due to weld heat and accompanying stresses.
[0004] In a further conventional gas water heater, the flue tubes are welded directly to the bottom and top heads of the tank. The high temperatures produced when the glass lined flue tubes, tank heads and bottoms and tank shells are welded together can cause the corrosion-protective glass-lining surfaces to chip and crack, exposing the bare steel underneath. Such flaws in the glass-lining surface often lead to premature tank failure.
[0005] The object of the present invention is to provide a water heater construction and method of manufacture wherein the problem of cracking of the lining due to weld heat and accompanying stresses in the various joint, radius and adjoining areas is substantially eliminated.
Description of the Drawings
[0010]
Fig. 1 is a side elevation view (with parts broken away) of a water heater tank assembly constructed in accordance with the present invention;
Fig. 2 is a top plan view of the water heater tank shown in Fig. I;
Fig. 3 is a fragmentary sectional view showing a typical prior art water heater tank construction;
Fig. 4 is an enlarged fragmentary sectional view of the circled portion of the water tank shown in Fig. 1; and
Fig. 5 is an enlarged fragmentary sectional view of the joint between the bottom head member and the shell.
Description of the Preferred Embodiment
[0011] The water heater tank construction of the present invention relates to gas or oil fired water heaters and more particularly to commercial gas or oil fired water heaters.
[0012] Referring to Fig. 1, the water heater tank assembly 10 is constructed of the following basic parts, namely, a shell 12, a top head member 14, a bottom head member 16 and a plurality of flue tubes 18. Top and bottom head members 14 and 16 are provided with flanges 32. A gas or oil burner assembly (not shown) of any suitable design is mounted in the combustion chamber 20 beneath the bottom head member 16. The products of combustion which pass upwardly through flue tubes 18 are carried from the heater by an appropriate venting means of any suitable design mounted on the top of the heater.
[0013] As best shown in Fig. 4, an important feature of the present invention is the use of collar members 22 for mounting flue tubes 18 in top and bottom head members 14 and 16. Each collar member 22 is comprised of a circular flange portion 26 having a cylindrical body portion 24 extending therefrom and formed integrally therewith. Collar members 22 are mounted in fluetube mounting openings 36 in the top and bottom head members 14 and 16. Details of the construction and advantages attained by collar members 22 will be set forth in detail hereinafter.
[0014] In the preferred embodiment, the water heater of the present invention is constructed as follows.
[0015] The first step is to mount collar members 22 in openings 36 in top and bottom head members 14 and 16 with the flange portions 26 positioned against the inside surface of the head members. The next step is to weld the flange 26 of each collar 22 to the inside surface of the top and bottom head members 14 and 16 by a weld designated by reference numeral 28. It should be noted at this point that the final assembly arrangement of collar members 22 and flue tubes 18 in top head 14 and bottom head 16 is identical, so identical reference numerals are used.
[0016] The next step is to apply a glass lining to what will become the inside (water side) of top and bottom head members 14 and 16 with collar members 22 welded thereto. The glass lining will thus cover the inner surface of the head members and the surfaces of the collar flanges 26 and the weld 28 between the flanges and the inner surfaces 22A of the cylindrical body portions of the collars 22. The reference numeral 29 designates the glass lining on the interior surfaces of the water heater. It will be appreciated that the glass lining is not drawn to scale.
[0017] The next step is to press fit the top member 14 and the bottom member 16 into the ends of shell member 12 with flanges 32 thereon extending upwardly and downwardly away from the interior of the shell. The shell member will have had a glass lining applied to its internal surface prior to this step.
[0018] Either the flange 32 of the top head member 14 or the bottom head member 16 is then welded to the shell by a weld 34. For purposes of explanation, the bottom head 16 will be welded to shell 12 first. Flange 32 is made sufficiently long so that the glass lining on the head will not be damaged when weld 34 is made. In the preferred embodiment, the minimum length of flange 32 on top and bottom head members 14 and 16 is approximately 7.3 mm (2-7/8 inches).
[0019] Next, flue tubes 18 are inserted into collars 22 with the opposite ends of the flue tubes 18 extending past the ends of the cylindrical body portions 24 of collar members 22. The flue tubes 18 will have been glass-lined on their external surface prior to such assembly.
[0020] Next, the lower ends of flue tubes 18 are welded to the ends of cylindrical body portions 24 of collars 22 by welds 30. Here again, by the use of collars 22 having a configuration as described above, weld 30 will be made at a location remote from the glass lining on the head 16 and collar flanges 26. The metal of the collar body 24 and flange 26 act as a heat sink during welding to thus prevent damage to the glass lining. In the preferred embodiment, the minimum length of cylindrical body portions 24 (from the top surface of flanges 26) is approximately 20 mm (13/16 inches).
[0021] At this point, reference is made to Fig. 3, which shows a typical prior art water heater tank construction. As shown, the flue tubes 19 are welded directly to the head 17. Because of the close proximity of the weld 31 to the bottom head glass lining 29, the heat produced, when making the weld, could, in some instances, cause the glass lining to crack, ultimately leading to premature tank failure.
[0022] Next, the upper ends of flue tubes 18 are welded to the ends of cylindrical body portions 24 of collars 22 by a weld 30. Here again, collars 22 serve as a heat sink during welding to prevent damage to the glass lining on top head 14. The final step is to weld the flange 32 of top head 14 to the shell 12 by a weld 34.
[0023] It should be noted at this point that it is important to make welds 30 at both the top and bottom of flue tubes 18 before the final weld 34 is made between the top head 14 and the shell. By following this procedure, the top head can "float" with respect to the shell when welds 30 are made. It will be appreciated that when welds 30 are made, there will be some expansion and contraction of the parts, which movement will be accommodated by the "floating" relationship between the top head and the shell.
a shell (12) having a top head member (14) and a bottom head member (16) welded in the ends thereof, the interior surfaces of said water heater tank assembly (10) being lined by a glass-lining (29) characterized in that said top and bottom head members (14,16) have a plurality of aligned flue tube mounting openings (36) therein,
a plurality of metal collar members (22) is mounted in said flue tube mounting openings (36), each of said collar members (22) having a circular flange portion (26) and a cylindrical body portion (24) extending therefrom, said collar members (22) being mounted in said flue tube mounting openings (36) with said flange portions (26) positioned against the inside surface of said top and bottom head members (14, 16) and with said cylindrical body portions (24) extending through said flue tube mounting openings (36) to a point above and below the external surface of said top and bottom head members (14,16), said collar members (22) being welded to said top and bottom head members (14, 16) by a weld (28) extending around the periphery of said flange portions (26) on said collar members (22); and
a plurality of flue tubes (18) having a glass-lining (20) on their external surface is mounted in the cylindrical body portions (24) of said collar members (22) with the ends of said flue tubes (18) extending past the ends of said cylindrical body portions (24) of said collar members (22), said flue tubes (18) being welded to said collar members (22) by a weld (30) extending around the ends of said cylindrical body portions (24) of said collar members (22).
(1) mounting a plurality of collar members (22) in the flue tube mounting openings (36) in a top head member (14) and a bottom head member (16), said collar members (22) having a circular flange portion (26) and a cylindrical body portion (24) extending therefrom, said collar members (22) mounted in said flue tube mounting openings (36) with said flange portions (26) positioned against the water side surface of said top and bottom head members (14, 16) and with said cylindrical body portions (24) extending through said flue tube mounting openings (36) to points above and below the external surface of said top and bottom head members (14, 16);
(2) welding the flange portion (26) of each collar member (22) to the inside surface of the top and bottom head members (14,16);
(3) applying the lining as a glass lining (29) to the water side surface of top and bottom head members (14, 16) with the collar members (22) welded thereto;
(4) friction fitting said top and bottom head members (14,16) into the opposite ends of a shell member (12), said shell member (12) having had a glass lining applied to its internal surface prior to this step;
(5) welding either the top or bottom member (14, 16) to the shell (12);
(6) inserting flue tube member (18) into the collar members (22) with the ends of the flue tube members (18) extending past the ends of the cylindrical body portions (24) of the collar members (22), the flue tubes (18) having been glass lined on their external surface prior to this step;
(7) welding the flue tube members (18) to the cylindrical body portions (24) of the collar members (22); and
(8) welding either the top or bottom head member (14, 16) to the shell (12) depending upon whether the top or bottom member (14, 16) was welded to the shell (12) in step (5).
(1) das Montieren einer Mehrzahl von Kragenteilen (22) in die Rauchrohr-Montageöffnungen (36) in einem oberen Abschlußteil (14) und einem unteren Abschlußteil (16), wobei die Kragenteile (22) einen kreisförmigen Flanschabschnitt (26) und einen sich davon wegerstreckenden zylindrischen Körperabschnitt (24) enthalten, wobei die Kragenteile (22) in den Rauchrohr-Montageöffnungen (36) derart montiert sind, daß die Flanschabschnitte (26) gegen die dem Wasser zugewandte Oberfläche des oberen und des Bodenabschlußteils (14,16) gerichtet positioniert sind, und wobei die zylindrischen Körperabschnitte (24) sich durch die Rauchrohr-Montageöffnungen (36) bis zu einem Punkt hindurcherstrecken, der über und unter der äußeren Oberfläche des oberen und des Bodenabschlußteils (14, 16) liegt,
(2) Schweißen des Flanschabschnittes (26) jedes Kragenteils (22) an die innere Oberfläche des oberen und des Bodenabschlußteils (14, 16),
(3) Aufbringen des Überzuges in Form eines glasigen Überzuges (29) auf die dem Wasser zugewandte Oberfläche der oberen und Bodenabschlußteile (14, 16) mit den daran angeschweißten Kragenteilen (22),
(4) Aufbringen der oberen und Bodenabschlußteile (14, 16) in die gegenüberliegenden Enden eines -Mantelteils (20) durch Reibungssitz, wobei das Mantelteil (12) vor diesem Verfahrensschritt mit einem auf seine Innenseite aufgebrachten glasigen Überzug versehen wurde,
(5) Schweißen entweder des oberen oder des Bodenabschlußteils (14, 16) an den Mantel,
(6) Einführen eines Rauchrohrteils (18) in die Kragenteile (22), wobei die Enden der Rauchrohrteile (18) sich über die Enden der zylindrischen Körperabschnitte der Kragenteile (22) hinauserstrecken, die Rauchrohre (18) wurden vor diesem Verfahrensschritt an ihrer äußeren Oberfläche mit dem glasigen Überzug versehen,
(7) Schweißen der Rauchrohrteile (18) an die zylindrischen Körperabschnitte (24) der Kragenteile (22), und
(8) Schweißen entweder des oberen oder des Bodenabschlußteils (14, 16) an den Mantel, in Abhängigkeit davon, ob das obere oder das Bodenabschlußteil (14,16) in Verfahrensschritt (5) an den Mantel (12) angeschweißt wurde.
un corps (12) comportant un élément de bout supérieur (14) et un élément de bout inférieur (16) soudés aux extrémités de celui-ci, les surfaces intérieures dudit ensemble de réservoir de réchauffeur d'eau (10) étant revêtues d'un revêtement vitrifié (29), caractérisé en ce que
lesdits éléments de bout supérieur et inférieur (14, 16) comportent une pluralité d'ouvertures (36) de montage de tubes formant carnaux alignées,
une pluralité d'éléments de colliers (22) de métal sont montés dans lesdites ouvertures (36) de montage de tubes formant carnaux, chacun desdits éléments formant colliers (22) comporte une partie (26) formant une collerette circulaire et une partie (24) formant un corps cylindrique qui s'étend à partir de celle-ci, lesdits éléments formant colliers (22) étant montés dans lesdites ouvertures (36) de montage de tubes, lesdites parties formant des collerettes (26) étant placées contre la surface intérieure desdits éléments de bout supérieur et inférieur (14, 16) et lesdites parties (24) formant un corps cylindrique s'étendant dans lesdites ouvertures (36) de montage de tubes formant carnaux jusqu'à un point situé au-dessus et respectivement au-dessous de la surface extérieure des éléments de bout supérieur et inférieur (14,16), lesdits éléments formant colliers (22) étant soudés auxdits éléments de bout (14, 16) supérieur et inférieur, au moyen d'une soudure (28) s'étendant à la périphérie desdites parties formant collerettes (26) sur lesdits éléments formant colliers (22);
et une pluralité de tubes formant colliers (18) comportant un revêtement vitrifié (29) sur leur surface extérieure, sont montés dans les parties (24) formant un corps cylindrique desdits éléments formant colliers (22), les extrémités desdits tubes formant carnaux (18) s'étendant au-delà desdites extrémités des parties (24) formant un corps cylindrique desdits éléments formant colliers (22), lesdits tubes formant carnaux (18) étant soudés auxdits éléments formant colliers (22) par une soudure (30) s'étendant autour des extrémités desdites parties (24) formant un corps cylindrique desdits éléments formant colliers (22).
(1) montage d'une pluralité d'éléments formant colliers (22) dans les ouvertures de montage de tubes formant carnaux (36) d'un élément de bout supérieur (14) et d'un élément de bout inférieur (16), lesdits éléments formant colliers (22) comportant une partie formant collerette (26) circulaire et une partie formant un corps cylindrique (24) qui s'étend à partir de celle-ci, lesdits éléments formant colliers (22) montés dans lesdites ouvertures de montage de tubes, lesdites parties formant collerette (26) étant placées contre la surface située du côté de l'eau desdits éléments de bout (14, 16) supérieur et inférieur, et lesdites parties (24) formant un corps cylindrique s'étendant dans lesdites ouvertures (36) de montage de tube jusqu'à des emplacements situés au-dessus et au-dessous de la surface extérieure desdits éléments de bout (14, 16) supérieur et inférieur;
(2) soudure de la partie formant collerette (26) sur la surface intérieure des éléments de bout (14, 16) supérieur et inférieur;
(3) application d'un revêtement tel qu'un revêtement vitrifié (29) sur la surface située du côté de l'eau des éléments de bout (14, 16) supérieur et inférieur, comportant soudés sur eux les éléments formant colliers (22);
(4) emmanchement serré desdits éléments de bout (14, 16) supérieur et inférieur dans les extrémités opposées d'un élément formant corps (12), ledit élément formant corps (12) comportant un revêtement vitrifié appliqué sur sa surface intérieure préalablement à cette opération;
(5) soudure soit de l'élément de bout supérieur (14), soit de l'élément de bout inférieur (16) avec le corps (12);
(6) insertion des éléments de tubes formant carnaux (13) dans les éléments formant colliers (22), les extrémités des éléments de tubes formant carnaux s'étendant au-delà des extrémités des parties (24) formant un corps cylindrique des éléments formant colliers (22), les tubes formant carnaux (18) ayant été revêtus d'émail vitrifié sur leur surface externe préalablement à cette opération;
(7) soudure des éléments de tubes formant carnaux (18) avec les parties (24) formant un corps cylindrique des éléments formant colliers (22); et
(8) soudure, soit de l'élément de bout supérieur (14), soit de l'élément de bout inférieur (16) au corps (12), selon qu'à l'opération (5) on a soudé avec le corps (12), l'élément de bout inférieur (16) ou bien l'élément de bout supérieur (14).