EP0601253B1 - Cast iron boilers - Google Patents

Description

The present invention relates to cast iron boilers whose hydraulic circuit is formed from a set of molded elements obtained without the use of foundry cores.

Such boilers are known in principle, for example by European Patent Application No. EP-A-0 414 925 and the published German Patent Application DE 41 19 866 C1. They are formed by assembling such elements delimiting an internal volume traversed by the combustion products and an external or peripheral volume traversed by the water of the heating circuit. This external volume must therefore both offer the minimum resistance to the circulation of water from each element to the next and a perfect seal.

In EP-A-0 414 925, the elements are cylindrical boxes having an H-shaped axial section (with the exception of the end elements) and are assembled facing each other along their open sides, with interposition of seals, all of these boxes and said seals being compressed by means of a series of tensioned tie rods internally traversing the entire length of the boxes, being distributed peripherally at the rate of one tie for each section formed of a longitudinal series of boxes. Any axial movement of boxes is therefore practically impossible. However, such an assembly, implying the installation of as many tie rods as boxes in a cross section and their tensioning uniformly distributed, is
Obviously long and complicated, especially in case of disassembly for the maintenance or replacement of said boxes. In addition, sealing must be ensured at the end of each tie rod.

In the system of DE 41 19 866 C1, similar boxes are created by the assembly of parts having in axial section the shape of a T, the bar of each T being tapered towards the ends to come to be embedded in a groove from the bottom of an inverted T adjoining it, said parts being oriented alternately outward and inward. The assembly therefore consists, in fact, of cylinder sections joined by transverse spacers each having an opening for the circulation of water. It is clear that this asymmetrical arrangement is inevitably creating stress imbalances detrimental to the solidity of the boiler. Likewise, it appears difficult to ensure satisfactory compatibility between the solidity of the spacers and the ease of circulation of the water through sufficient openings. Finally, the necessary sealing requires additional seals tightened by means of tie rods stretched between each successive pair of spacers.

The present invention eliminates the various drawbacks which emerge from the above description of the state of the art, that is to say the complexity of the parts and their assembly and in particular the need to ensure their tightening by means tight tie rods.

For this purpose, the water circuit of a boiler according to the invention consists of a succession of sections of cast iron ferrules, each section being slightly frustoconical in at least one direction so that its small face comes to adapt tightly in the large face of a contiguous section, all of the assembled sections constituting a toroidal volume, the two peripheral surfaces of which are kept apart by annular transverse spacers pierced with openings allowing the circulation of water in the axial direction, said assembly being held by means of tie rods external to the boxes, bearing on ears distributed over the periphery of the end ferrules.

According to a first embodiment, all the sections of ferrules are oriented in the same direction, the large face of each section constituting the spacer corresponding to the corresponding cross section of the boiler. In this case, the front edge of the small face of each section abuts against the large rear face of the neighboring section, the seal being ensured by an appropriate seal.

According to a second embodiment, the sections are oriented alternately in one direction and in the other, the assembly being done by the small facing faces of two successive sections with the interposition of a thin annular piece itself constituting both the and the gasket.

• La figure 1 est une coupe axiale d'une première réalisation de l'invention,
• La figure 1A est une vue agrandie d'un détail de la figure 1,
• La figure 2 est une coupe suivant II-II de la figure 1,
• La figure 3 est une vue en perspective avec arrachement partiel de l'un des tronçons de la chaudière selon les figures 1-2,
• La figure 4 est une coupe axiale d'une seconde réalisation de l'invention,
• La figure 4A est une vue agrandie d'un détail de la figure 4,
• La figure 5 est une coupe suivant V-V de la figure 4,
• La figure 6 est une vue en perspective avec arrachement partiel de l'un des tronçons de la chaudière selon les figures 4-5,
• Et la figure 7 est une vue partielle en perspective d'un détail de la figure 4.

The invention will now be described in more detail with reference to the accompanying drawing in which:

• FIG. 1 is an axial section of a first embodiment of the invention,
• FIG. 1A is an enlarged view of a detail of FIG. 1,
• FIG. 2 is a section along II-II of FIG. 1,
• FIG. 3 is a perspective view with partial cutaway of one of the sections of the boiler according to FIGS. 1-2,
• FIG. 4 is an axial section of a second embodiment of the invention,
• FIG. 4A is an enlarged view of a detail of FIG. 4,
• FIG. 5 is a section along VV of FIG. 4,
• FIG. 6 is a perspective view with partial cutaway of one of the sections of the boiler according to FIGS. 4-5,
• And FIG. 7 is a partial perspective view of a detail of FIG. 4.

Referring first to Figures 1-2, there is shown a boiler according to the invention consisting in known manner of a heating body 1 completed by an insulated front panel A and a rear panel B through which are evacuated combustion products.

With the aim of delimiting the internal volume 1 traversed by the combustion products and the external volume 2 intended to be traversed by the water of the heating circuit, the invention provides for the assembly of two series of cast iron ferrules 4 and 5 , slightly frustoconical so that the edge of the small front face 6 a of an outer shell 4 a abuts against the large rear face 7 b of the next outer shell 4 b , and that likewise, the edge of the small face 6 ' a of an interior ferrule abuts against the large face 7' b of the following interior ferrule, each embedding being sealed by means of a lining 8, for example made of silicone or the like. Optionally, the positioning or centering of a small face with respect to a large face can be ensured by a peripheral rim thereof, or by a number of ribs 17 distributed over the outer periphery of the outer ferrules 4, as shown.

The large faces 7 of each pair of ferrules 4-5 together constitute spacers in the form of crowns 9 holding the ferrules apart and pierced with openings 20 ensuring the circulation of water.

In practice, each pair of ferrules 4-5 and its spacer 9 constitutes a single circular piece of cast iron with a U-section, obtained by casting without a core, so that a boiler thus produced according to the invention by simple axial assembly d 'a series of such circular parts is much simpler and more robust in construction than the previous boilers described above.

Such an assembly is obtained by means of tie rods 21 exterior to the exterior ferrules 4 passing through ears 18 distributed over the periphery of the exterior ferrules of ends to ensure solidity and tightness, and the tension of which is ensured by means of nuts 22.

In the second embodiment, illustrated in FIGS. 4-5, the interior and exterior ferrules, respectively 10 and 11, are oriented alternately in one direction and in the other, so that their small faces are facing each other, and that they are assembled, as illustrated in FIG. 4 A by an intermediate piece 12 constituting an annular spacer comprising water circulation openings (13). In this version, a part 23 inserted between two pairs of ferrules 10a, 10b, 11a, 11b can itself constitute the seal ensuring the seal between these ferrules. In this case, it may have the appearance of a metallo-plastic joint as shown in FIG. 5, where a gasket 23 having openings 14 is crimped in a metal strip 15.

As in the first version, the ferrules 10 and 11 are obtained together by coreless casting and assembled by external tie rods 21 tightened by nuts 22. The end pieces are similar to those of the first version, while the intermediate pieces are symmetrical about their mid-section.

The advantages of the two versions are the same: simplicity of obtaining and assembling successive parts, which can advantageously be provided with fins 16 improving the heat exchange.

Although FIGS. 2 and 5 illustrate a circular toroidal shape for the water circuit produced according to the invention, it can be produced in an equivalent manner in polygonal form, the peripheral surface of each ferrule 4, 5, 10 and 11 then being formed of a succession of planes.

Claims (6)

1. Boiler of the type in which the water circuit is formed of cast-iron elements obtained by solid-casting, characterised by the fact that the said elements each form a discrete cast transverse boiler section defined by a pair of concentric shell members (4, 5, 10, 11) slightly in the shape of truncated cones, separated by an annular base (9, 12) having water circulation orifices (20, 13), the successive sections being assembled by external braces (21) tightened by nuts (22) passing through lugs (18) on the end shell members with interposition of a gasket (8, 12) between the periphery of one shell member and the base of the next.
2. Boiler in accordance with claim 1, characterised by the fact that the elements of all the sections are oriented in the same direction, the small face (6a) of one shell member abutting against the large face (7b) of the next.
3. Boiler in accordance with claim 1, characterised by the fact that the elements of a section, with the exception of the end sections, consist of the association in one single cast piece of two pairs of shell members shaped slightly as truncated cones oriented in opposite directions and the large faces of which are integrally connected by an annular piece (12) having water circulation orifices (13), the small faces (11a, 11b, 10a, 10b) of two such successive sections being assembled with interposition of a perforated annular piece (23), the two faces of this annular piece (23) receiving the said small faces of two adjacent elements with interposition of a gasket.
4. Boiler in accordance with claim 3, characterised by the fact that the said annular piece (23) receiving the said small faces itself constitutes a common gasket.
5. Boiler in accordance with claim 4, characterised by the fact that the said common gasket is a filled-metal jacketed gasket formed by a strip (23) having perforations (14) and set in a metal strip (15).
6. Boiler in accordance with any of the preceding claims, characterised by the fact that each inner shell member is provided with vanes (17) oriented towards the firebox in order to improve heat exchange.

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