EP1528319A1

EP1528319A1 - Prefabricated flue system and methed of assembly thereof

Info

Publication number: EP1528319A1
Application number: EP04105296A
Authority: EP
Inventors: Salvatore Greco
Original assignee: Ligure Sarda SpA
Current assignee: Ligure Sarda SpA
Priority date: 2003-10-30
Filing date: 2004-10-26
Publication date: 2005-05-04
Also published as: ITSV20030044A1

Abstract

A prefabricated flue system, comprising at least one first outer tubular casing element (1) and at least one second inner tubular element (2) for conducting flue gas, which two elements are disposed the latter (2) inside the former (1) and with their longitudinal axes essentially parallel and/or coincident. According to the invention, the first outer casing element (1) is formed by two parts (101, 201), adapted to be coupled to and uncoupled from each other (301, 401), means (3) being provided for removably securing the second element (2) to one of said two parts (101, 201) of the outer casing element (1), whereas the second part (201) of said first outer casing element (1) acts as a wall for externally covering and/or closing the housing of the inner element (2).

The invention also provides a method for assembling said flue system.

Description

The present invention relates to a prefabricated flue system as described in the preamble of claim 1.

Prefabricated flue systems comprise at least one first outer tubular casing element and at least one second inner tubular element for conducting flue gas, which two elements are disposed the latter inside the former and with their longitudinal axes essentially parallel and/or coincident.

Particularly, the invention relates to prefabricated flue systems composed of a plurality of prefabricated sections that can be tightly fitted one into the other. In these flue systems one end of the second inner tubular element of each flue section has a bell joint, whereas the opposite end is shaped like a terminal complementary to said bell joint. Also, the two opposite ends of the outer tubular casing element are shaped like complementary connection or press-fit terminals. The whole is designed in such a manner that, when the sections of the second inner tubular element are coupled together, the sections of the first outer tubular casing element are also coupled.

In these prior art flues, the outer tubular casing element is a one-piece tubular element, i.e. stably closed on itself. This arrangement involves construction problems during fabrication of the flue or flue sections and, when a flue section breaks, the whole section, i.e. both the outer tubular casing element and the inner element, needs to be replaced. Further, the prefabricated sections, including both the outer casing element and the inner element in a single prefabricated and preassembled element have a heavy weight, which makes assembly and/or maintenance thereof inconvenient and dangerous, as such operations have to be performed at a considerable height.

Typically, the whole of such flue systems, or a part of them, e.g. the outer tubular casing element or the inner tubular element, are made of metal, e.g. stainless steel sheet or other suitable metals. This material may be also obviously used for the flue according to this invention, as one of the options, among several different metal or non-metal materials.

For the maintenance or renovation of building fronts, changing of prior art flues is only limited to the external color. However, no change is possible on the material of the outer tubular element of these flues, not even for the exposed portion, hence a number of different and often complex manual tools are required, to ensure safe fastening of external finishes.

The invention has the object of providing a flue system like the one described hereinbefore that, by using simple and inexpensive arrangements, may obviate the above drawbacks, while allowing an easier and faster installation thereof, and adding versatility thereto, in terms both of technical features and of aesthetic adaptation.

The invention fulfils the above objects by providing a flue system which, in combination with the characteristics of the preamble of claim 1, also has the characteristics of the characterizing part of claim 1.

Particularly, the first outer casing element is formed by two parts, adapted to be coupled to and uncoupled from each other, means being provided for removably securing the second element to one of said two parts of the outer casing element, whereas the second part of said first outer casing element acts as for externally covering and/or closing the housing of the inner element, therefore the fabrication of the flue system is easier and less expensive, and the parts thereof to be installed have a lighter weight.

Especially, when multiple flue sections are provided, to be fitted one inside the other, the flue system of the present invention also has press-fit and/or connection terminals at the ends of both the sections of the second inner tubular element and the first and second part of the first outer tubular casing element.

As better shown by the description hereafter, the press-fit and/or connection ends of the sections of the second inner tubular element and of the two parts of the first outer tubular casing element have such a size that the press-fit stroke of two adjacent sections of the second tubular element is defined by and corresponds to the connection or press-fit distance of two adjacent sections of the corresponding first and second parts of the outer tubular casing element, which are themselves defined in terms of both length and relative position by the press-fit stroke of the corresponding adjacent sections of the second tubular element.

In terms of assembly of a flue system according to the invention, in a first embodiment, the sections of the first parts of the first outer tubular casing element need only be assembled, by sequentially fastening them to a wall, e.g. the outer wall of a building, i.e. by placing the connection or press-fit terminals of the sections of the first part of the outer tubular casing element in the proper coupling position, thereby forming a continuous element for housing and securing the second tubular element.

In the second step, each section of the second tubular element is mounted in its respective section of the first parts of the outer tubular casing element, and is sequentially secured to the corresponding first part in its predetermined relative position, by using removable fastener means.

Once the first section of the second tubular element has been fastened in the corresponding first section of the first part of the first outer tubular casing element, the next section of the second tubular element simply has to be fitted in the corresponding press-fit end of the first section of the second tubular element and locked to the corresponding section of the first part of the first outer tubular casing element. In fact, since the section of the second tubular element is already fastened to the corresponding first part section, the next section of the second tubular element is supported by the first section and the operating personnel can fasten it in an easy and safe manner.

The last step is the installation of second covering and closing part of the first outer tubular casing element, which are mounted in exactly the same manner as the previous parts.

Intermediate steps may be also provided for inserting intermediate elements to cover the sections of the second inner tubular element. These intermediate elements may be also provided in multiple parts, of such sizes and shapes as to fit the length and the shape of the sections of the second inner tubular element, as well as the internal shape of the first outer tubular casing element.

Thus, operations are apparently carried out in a totally safe manner.

The assembly method also provides considerable advantages when transverse deflected or branched portions of the second inner tubular element must pass across the masonry. In this case, the above method has a very simple operation, thanks to the structure of the flue system of the invention. In fact, once the sections of the first part of the outer tubular casing element have been mounted, holes may be formed in proper positions of the wall that supports them or said first parts may be properly positioned in previously formed holes. To this end, an opening may be already provided in the wall of the sections of the first part of the first outer tubular casing member, or said first part may be provided in the form of a frame, with an open wall portion, or a hole may be also newly formed in the wall of said first part. Furthermore, regarding the installation of the second inner tubular element, all desired adaptations may be simply made to properly center the pre-formed openings or newly formed holes with the transverse branched or deflected portions.

Please note that flue systems according to this invention especially find application in the renovation of existing buildings, where the adaptation to existing conditions is of the utmost importance.

Regarding the second part of the outer tubular casing element, thanks to the fact that it may be easily coupled to and uncoupled from the first part, which is fastened to or carries the second inner tubular element, aesthetic arrangements and servicing on the flue system become very easy, fast and flexible. In fact, several different materials may be used at least for the exposed face of said first part, and at least the exposed outer layer of said second part of the outer tubular casing element may be replaced without dismantling the whole flue system, which keeps its features unaltered. The invention apparently also allows to make maintenance and replacement of damaged and worn parts easier and less expensive.

It shall be noted that, while the embodiment as shown in the figures relates to a flue system having one second inner tubular element, the flue may also have two, three or more inner tubular elements.

Furthermore, the flue system according to the invention may have any sectional shape, in addition to the square section that is shown in the figures, e.g. a round, polygonal, circular, elliptical, semicircular, semielliptical shape or the like.

Also, regarding the materials for flue systems, any type of suitable material may be used, i.e. any material having a sufficient heat resistance.

It shall be further noted that the claimed structure may be used for any type of tubular piping, such as drainage pipes for storm and/or sanitary waters or pipes for aeration systems, or other pipes.

Further improvements of the invention will form the subject of the dependent claims.

The characteristics of the invention will appear more clearly from the following description of one embodiment, which is shown by way of non-limiting example in the annexed drawings, in which:

Figs. 1 and 2 show two elevational assembly views, as seen from the front side and perpendicular to the front side respectively, of a flue system according to the invention, which is formed by a plurality of prefabricated sections.

Figs. 3 and 4 are front and side sectional views respectively of the flue system of the previous figures, the second covering or closing part of the first outer tubular casing element.

Figs. 5 and 6 are views like the previous Figures 3 and 4 of the flue system of the previous figures in the assembled condition.

Figs. 7 and 8 are two cross-sectional views of the flue system as shown in the previous figures, the former showing the condition in which the second covering or closing part of the outer tubular casing element is removed from the first part, and the latter showing the condition in which said parts are assembled.

Fig. 9 is a view similar to that of Figure 8, in which an intermediate layer is provided for covering the second inner tubular element.

Figures 1 and 2 show a prefabricated flue system composed of a plurality of prefabricated sections having essentially the same construction, except a few variants to be described hereafter.

In the first section, the second tubular element has a T shape, with a transverse branched portion which is connected to the outlet of a boiler and passes through a peripheral wall.

Under such first section, another section is provided, which has the function of a condensate discharge and inspection terminal, and has a door for opening and accessing the inner space of the flue.

The second section has a window for accessing flue gas collection apertures for flue gas analysis. Cases may be further provided for containing measuring instruments, e.g. temperature or pressure measuring instruments.

Then, a predetermined number of identical successive flue sections follow up to a chimney top module having a rain cap terminal.

The next figures show the construction of one of the base module sections of the flue system as shown in Figures 1 and 2.

Each base module section has a section of a first outer tubular casing element 1, which contains a section of a second inner tubular element 2, the latter forming the flue gas conduit.

Each section of the outer tubular casing element 1 is formed by the corresponding sections of two

parts

101, 201, which may be coupled to and uncoupled from each other.

A first part 101 forms a section of a frame for securing a corresponding section of a second inner tubular element 2 and is designed to be attached to a wall or the like. This section of the first part 101 is a support frame, which is essentially flat but may also have a round or polygonal cross section, with flat portions for attachment thereof to the wall, i.e. flattened wall portions or flat wall attachment brackets.

In the embodiment of the figures, in which the cross section of the outer tubular casing element 1 has a quadrilateral, particularly square shape, the first part 101 forms one side of said square cross section. At least two tabs 501 project out of the upper side of the section of the first part, and have through holes therein, e.g. for hooks attached to the wall or for fastener means such as screw, bolts, or the like.

Further tabs and through holes, not shown, may be also provided within the surface of this section of the first part 101 of the outer casing element 1.

A bracket at one end of the section of the first part acts as a cradle for housing and fastening the corresponding section of the second inner tubular element 2. Particularly, the bracket has a concave surface 104 on the side to be coupled to the corresponding section of the second tubular element 2, whose shape is complementary to the shape of the second tubular element and which extends over an angular width of about 180°. Two flat portions are provided at the two sides of the cradle, for engagement of the threads of two bolt fasteners, or the like, of a half-collar 204. Thus, the section of the second inner tubular element 2 is clamped between the concave portion 104 of the cradle 4 and the half collar 204.

In this embodiment, the section of the inner tubular element 2 is only retained at its upper end 102, which forms a bell joint for the terminal 202 of another flue section, identical to the one described above, and also having a section of the second tubular element 2. It is apparent that, while another combination of a cradle 4 and a half collar 204 may be provided in at least one more location of the longitudinal extension of the section of the second inner tubular element 2, one of such combinations is sufficient, at the bell joint 102, to ensure that each section of the second inner tubular element 2 is retained in the proper position by the bell joint of the preceding, i.e. underlying section of the second inner tubular element 2. This allows to considerably reduce the time and material required to couple the section of the second inner tubular element 2 to the corresponding section of the first part 101 of the first outer tubular casing element 1.

The second part 201 of the outer tubular casing element 1 is also divided into sections, which correspond to first part sections 101 and to inner tubular element sections 2.

Each section of the second part 201 of the outer tubular casing element 1 has a concave shape and has a front wall extending by two side branches which are designed to lie over essentially the whole side thickness of the corresponding section of the first part 101 or the side tabs 201 of said first part section.

The embodiment of the figures, which shall be intended without limitation, relates to a square shape, and the sections of the second part 201 have a U shape, i.e. with a front wall parallel to the first part 101 and the two side walls perpendicular to the front wall and to the first part 101.

As mentioned above, several different cross sectional shapes may be provided, which may be quadrilateral, e.g. rectangular, trapezoidal, rhomboidal shapes, or round, circular, elliptical, polygonal shapes, or combinations thereof. Also, even when the sections of the second part 201 do not extend to the attachment wall of the section of the first part 101 of the first outer tubular casing element 1, this may provide advantages, because the sections of the second part may have advantageous aesthetic functions, in that they add versatility to the inventive flue system, allowing it to be easily adapted to the overall aesthetic aspect of the building in which the flue system is provided.

The side walls of the sections of the second covering or closing part 201 of the outer tubular casing element 1 lie, by their longitudinal terminal portions, over the thickness of the corresponding section of the first part 101 or over the side tabs 501 of the latter. These side tabs 501, which may be continuous or discontinuous and/or the longitudinal side edges of the sections of the first part 101 extend in a fashion that is coplanar or corresponding to the side walls of the section of the second covering or closing part 201, which lies over them.

Within the thickness of each section of the first part 101 of the outer tubular casing element 1 or in the continuous or discontinuous side tabs 501, at least in the two end portions, means 301 are provided for removable coupling to corresponding removable coupling means 401, located in a corresponding position in the superimposed portions of the side walls of the sections of the second covering or closing part 201 of the outer tubular casing element 1.

In a particular embodiment, the

means

301, 401 for mutually removably coupling the section of the first part 101 and the corresponding section of the second part 201 of the outer casing element 1 may be, for example, hooks with an upturned open side, with reference to the vertical extension of the flue, in the first part, and, for each hook 301 of the first part 1, a transverse engaging member 401 in the second part 201, i.e. a stirrup projecting inwardly from the corresponding inner surface of the second part, or transverse members connecting two opposite edges of an aperture 601 in which the corresponding hook 301 has to be inserted, said aperture having such a size has to wholly accommodate the hook therein, between the transverse member 401 and a parallel edge of the aperture 601, particularly the lower edge of the aperture 601. Thanks to this arrangement, each section of the second covering or closing part 201 may be simply hooked to the corresponding section of the first part 101. When the hooks cooperate with cross members of apertures, the proper hooked condition may be also visually checked from the outside. Fastener screw means, or the like may be also combined with the hooks. The second part may be simply coupled to the first part, by placing the second part over the first part in a position in which the open sides of the hooks are turned toward the corresponding cross members, and by downwardly sliding the second part to fit the cross members into the hooks.

The above is only an example of the means for removably coupling the first and the second parts of the outer tubular casing element, and any removable coupling means may be provided, with a snap, interlock, clamp engagement operation, or the like.

Regarding the cross section of the outer tubular casing element 1, this shall not necessarily be a quadrilateral, and may particularly have an annular cross section, i.e. closed on itself, e.g polygonal or circular, and the cross section of the first part 101 of the outer casing element 1 may have an angular extension of 180° or less, whereas the second covering or closing part 201 may have an angular extension of 180° or more, i.e. corresponding to the angular extension of the first part 101.

According to another characteristic, and as provided in prior art prefabricated flue systems, the inventive flue system is also composed of a plurality of prefabricated segments with the above construction, which are tightly fitted one into the other.

In this case, the sections of the second inner tubular element 2 of each flue segment have a bell joint 102, whereas the opposite end is shaped like a terminal 202 complementary to said bell joint. The two opposite ends of the outer tubular casing element 1 are also shaped like complementary connection or press-fit terminals.

Particularly referring to the embodiment of the figures, each section of the first part 101 of the outer casing element 1 has, at the same end as the bell joint 102 of the second tubular inner element 2, a terminal 701, to be fitted in a recess formed at the end of the section of the first part of an adjacent flue section, which end is associated to the press-fit terminal 202 of the corresponding section of the second inner tubular element 2. The insertion stroke of the press-fit terminal 202 of the second inner tubular element 2 of a flue section in the bell joint 102 at the end of the second inner tubular element 2 of an adjacent flue section essentially corresponds to the connection distance or insertion stroke of the corresponding facing ends of the first outer tubular casing element 1. Particularly, the press-fit terminal 701 of the first part 101 of the outer casing element 1 of a flue section is a narrowing step transverse to the longitudinal extension of said flue section, which narrowing step has a length in the axial direction of the flue section that is essentially equal to the insertion stroke of two second tubular elements 2 of two adjacent flue sections. The two tabs 501 projecting out of the upper edge of this press-fit terminal have a size that corresponds to the recess of the facing end of the first part 101 of the adjacent flue section, so that the tabs 501 are housed in said recess and may be accessed from the outside.

The sections of the second covering or closing part 201 of the outer casing element 1, also have a terminal with a narrowing step 801 of such a size that the opposite end of an adjacent section of the second covering or closing part 201 lies over said step-like terminal and whose axial length essentially corresponds to the insertion stroke between two second inner tubular elements 2 of two adjacent flue sections and/or to the axial size of the press-fit terminal 701 of the first part 101 of the first outer tubular casing element 1. Therefore, each section of this second part 201 of the first outer casing element 1 is connected at its two opposite longitudinal ends flush with the adjacent section of the second part 201.

Thanks to the above construction, two assembly modes may be provided. In a first mode, all the sections of the first part 101 of the outer tubular casing element 1 are first sequentially assembled together, by coupling the facing connection terminals thereof. Then, all the sections of the second inner tubular element 2 are coupled together therein, and finally all the sections of the second covering or closing part 201 of the outer tubular casing element 1 are mounted thereon. This arrangement allows to reduce the weight of the parts to be assembled, to properly position the sections of the first part 101 of the outer tubular casing element with respect to apertures or passages for transverse branched or deflected portions, to monitor the coupling between the sections of the second tubular element 2 and to mount the second covering or closing parts 201, which are separated from the remaining parts and may be made of or covered by materials of a considerable weight, e.g. exterior coverings made of a stone material, such as rock, marble, granite or the like.

In a different mode, the sections of the first part of the outer tubular casing element 1 may be assembled together with the corresponding section of the inner tubular element 2 thereon, while the sections of the second part 201 of the outer tubular element 1 are always mounted separately, in a last assembly step.

The advantages of the present invention and the high flexibility of the inventive flue system are self-evident from the above description.

Hence, for example, in the flue system of the invention, the second part 201 of the first outer tubular casing element has one or more preformed inspection apertures to be closed by corresponding doors, possibly themselves prefabricated, which apertures may coincide with one or more closable inspection apertures formed in the second inner tubular element 2.

Alternatively to or in combination with the above, the second part 201 of the first outer tubular casing element 1 may have one or more prefabricated cases for housing measuring instruments, whose inner side has apertures for the wires to sensors, prefabricated or premounted in or on the second inner tubular element.

As described above, the section of the second inner tubular element 2 may have at least one transverse branched portion and/or one curved portion with a transverse branch 302, said transverse branch being turned toward the first part 101 or the second part 201 of said first outer casing element 1 and said first part 101 or said second part 201 having an aperture for the passage of said transverse branched portion or said transverse curved portion 302.

An intermediate covering layer 7 made of an insulating material may be provided between the first outer tubular casing element 1 and the second inner tubular element 2, which covering layer is shaped in such a manner as to be complementary to the outer side of the second tubular element 2 and/or to the inner side of at least a portion of the first part 101 and/or at least a portion of the second part 201 of the first outer tubular casing element 1. This intermediate insulating layer 7 is divided circumferentially into at least two or more complementary parts 107, 207 and/or longitudinally to correspond at least to the length of the flue sections or into pieces whose length is a submultiple of the length of said flue sections.

Depending on its cross section, the second covering or closing part 201 of the first outer casing element 1 may be composed of two or more parts, that may be removably coupled by complementary interlock or press-fit and/or clamp engagement means or hinged together to oscillate about at least one axis parallel to the longitudinal axis of the flue and/or to one or more transverse axes.

Furthermore, in combination with a first outer tubular casing element 1, two or more inner tubular elements 2 are provided having equal or different diameters, some or all of them being constructed according to one or more of the annexed claims. In this case, the cradles or brackets may be formed as described in prior art, in DE 3420554.

In this case, a cradle is provided having two, three or more housings, for two, three or more second inner tubular elements respectively.

From the aesthetic point of view, at least the second covering or closing part 201 of the first tubular casing element 1 is made of metal and/or plastic and/or of a multilayer material comprising at least one metal layer and at least one plastic layer. Hence, this second covering or closing part 201 of the first tubular casing element 1 acts as an anchorage or support element for a finishing layer, such as a paint layer and/or a layer formed by one or more finishing panels, e.g. made of metal, plastic, concrete, or a stone material such as rock, granite, marble or the like, or at least one multilayer panel comprising at least one support layer made of plastic or concrete, and one finishing layer made of metal, plastic or a stone material such as rock, granite, marble or the like. The sections of the second covering or closing part 201 of the first tubular casing element 1 may be also provided in the form of frames having means for removably fastening wall panels, such as through bolts, or the like.

The above is without departure from the guiding principle disclosed above and claimed below.

Claims

A prefabricated flue system comprising at least one first outer tubular casing element (1) and at least one second inner tubular element (2) for conducting flue gas, which two elements are disposed the latter (2) inside the former (1) and with their longitudinal axes essentially parallel and/or coincident, characterized in that the first outer casing element (1) is formed by two parts (101, 201), adapted to be coupled to and uncoupled from each other (301, 401), means (3) being provided for removably securing the second element (2) to one of said two parts (101, 201) of the outer casing element (1), whereas the second part (201) of said first outer casing element (1) acts as a wall for externally covering and/or closing the housing of the inner element (2).
A flue system as claimed in claim 1, characterized in that the first and the second part (101, 201) of the outer casing element have removable fastening means (301, 401), such as mutual hooking means and/or mutual interlocking means and/or mutual clamping means.
A flue system as claimed in claim 1 or 2, characterized in that a first part of the outer casing element (1) is a frame for securing the first casing element to a wall or the like, and has fastening means (501).
A flue system as claimed in claim 3, characterized in that said fastening means are tabs (501) with holes for engagement with hooks fixed in the wall and/or for attachment to said wall by screws, bolts or the like.
A flue system as claimed in one or more of the preceding claims 3 and 4, characterized in that at least some of the means for fastening the part (101) of the outer casing element (1) have through holes or slots for hooks, bolts, screws or the like for attachment to a wall, which holes or slots are placed within the perimeter of said wall.
A flue system as claimed in one or more of the preceding claims 3 to 5, characterized in that at least some of the fastening or clamping tabs (501) are provided on the contact side of the part (101) against the wall and project upwards out of the upper side of said part (101).
A flue system as claimed in one or more of the preceding claims, characterized in that the first part (101) of the outer casing element is a frame or a wall, at least a portion or the whole whereof is essentially the only side of the casing element turned toward the fastening wall, whereas the second covering and/or closing part (201) has a concave cross section, whose concavity is turned toward said first part (101).
A flue system as claimed in claim 7, characterized in that the second covering or closing part (201) of the outer casing element (1) has means along the longitudinal edges or in the band next to said longitudinal edges, for removably coupling it to said first part (101) of the outer casing element (1), which removable coupling means (301) cooperate with complementary means (401) located in corresponding positions on the first part (101) of the casing element.
A flue system as claimed in claim 7 or 8, characterized in that the first part (101) of the outer casing element (1) has a predetermined thickness along its two side edges, over which the end bands of the second part lie, or tabs extending continuously or discontinuously along said side edges of the first part (101) and projecting toward said second covering or closing part (201), the end bands of the second part (201) lying over said tabs along the two side edges, there being provided, in said end bands along the side edges of the first part (101) and at said thickness of the first part (101) and/or at said tabs, the complementary means for mutually removably coupling said first part and/or said second part (101, 201) of the outer casing element (1).
A flue system as claimed in one or more of the preceding claims, characterized in that the means (301, 401) for mutually removably coupling said first part (101) and said second part (201) of the outer casing element (1) are hooks with an upturned open side, with reference to the vertical extension of the flue, in the first part (101), and, for each hook (301) of the first part (101), a transverse engaging member (401) in the second part (201), i.e. a stirrup projecting inwardly from the corresponding inner surface of the second part, or transverse members connecting two opposite edges of an aperture (601) in which the corresponding hook (301) has to be inserted, said aperture having such a size has to wholly accommodate the hook therein, between the transverse member (401) and a parallel edge of the aperture (601), particularly the lower edge of said aperture (601).
A flue system as claimed in one or more of the preceding claims, characterized in that the outer tubular casing element (1) has an annular cross section, i.e. closed on itself, which is polygonal or circular or elliptical or semicircular or semielliptical and the cross section of the first part (101) of the outer casing element (1) has an angular extension of 180° or less, whereas the second covering or closing part (201) of the outer casing element (1) has an angular extension of 180° or more, i.e. corresponding to the angular extension of the first part (101).
A flue system as claimed in one or more of the preceding claims 1 to 11, characterized in that the outer casing element (1) has a quadrilateral cross section, e.g. a trapezoidal, square, rhomboidal or rectangular cross section, wherein the first part (101) forms one side of said quadrilateral shape and the second covering or closing part (201) forms the other three sides of said quadrilateral shape.
A flue system as claimed in claim 12, characterized in that the first part (101) of said outer casing element (1) has side tabs (501) extending at least partly along the two transverse walls, over which the two side walls formed by the second covering or closing wall (201) lie, the means (301, 401, 601) for mutually removably coupling said first part (101) to said second part (201) being provided in coincident positions and in the area of said side tabs (501).
A flue system as claimed in one or more of the preceding claims, characterized in that the first part (101) of the outer casing element (1) is internally shaped like a cradle (4) for housing the second inner tubular element (2), with a round, preferably circular shape, means (3) being associated to said cradle (4) for removably securing said second tubular element (2) to said cradle (4).
A flue system as claimed in claim 14, characterized in that the cradle (4) is formed by at least two brackets, secured to or integral with said first part (101) of the outer casing element (1), which brackets are provided at least at the two opposite ends of the second tubular element (2) and have a concave side (104) for housing said second tubular element (2) which is a half of a clamping collar, there being provided an additional half collar (204), to be fastened by screws against said concave side (104) and against the second tubular element (2) housed therein.
A flue system as claimed in one or more of the preceding claims, characterized in that the brackets that form the cradle (4) for the second inner tubular element (2) have a cross section that is complementary to the cross section of the first part (101) of the outer casing element (1) on the sides adjacent to the inner surface thereof and a concave cross section (104), with a shape corresponding to the outer skirt of the second inner element (2), particularly a semicircular shape, on the side in which said second inner tubular element (2) is housed.
A flue system as claimed in one or more of the preceding claims, characterized in that it is composed of a plurality of prefabricated segments to be tightly fitted one into the other, each segment being constructed as claimed in the preceding claims 1 to 16.
A flue system as claimed in claim 17, characterized in that one end of the second inner tubular element (2) of each flue section has a bell joint (102), whereas the opposite end is shaped like a terminal (202) complementary to said bell joint.
A flue system as claimed in claim 17 or 18, characterized in that the two opposite ends of the outer tubular casing element (1) are shaped like complementary connection or press-fit terminals.
A flue system as claimed in claim 19, characterized in that the first part (101) of the outer casing element (1) has, at the same end as the bell joint (102) of the second tubular inner element (2), a terminal (701), to be fitted in a recess formed at the end of the first part (101) of an adjacent flue section, which end is associated to the press-fit terminal (202) of the corresponding section of the second inner tubular element (2).
A flue system as claimed in one or more of claims 18 to 20, characterized in that the insertion stroke of the press-fit terminal (202) of the second inner tubular element (2) of a flue section in the bell joint (102) at the end of the second inner tubular element (2) of an adjacent flue section essentially corresponds to the connection distance or insertion stroke of the corresponding facing ends of the first outer tubular casing element (1).
A flue system as claimed in claim 21, characterized in that the press-fit terminal (701) of the first part (101) of the outer casing element (1) of a flue section is a narrowing step transverse to the longitudinal extension of said flue section, which narrowing step has a length in the axial direction of the flue section that is essentially equal to the insertion stroke of two second tubular elements (2) of two adjacent flue sections.
A flue system as claimed in claim 21 or 22, characterized in that at least two tabs (501) for fastening said part (101) to a wall project out of the upper edge of said press-fit terminal, which tabs (501) and the recess of the facing end of the first part (101) of the adjacent flue section have such a size that the tabs (501) are housed in said recess.
A flue system as claimed in one or more of the preceding claims, characterized in that the second covering or closing part (201) of the outer casing element (1) has a terminal for connection to the second part (201) of an adjacent flue section, one end of said second part sections being provided with a connection terminal (801) in the form of a narrowing step over which the opposite end of an adjacent section of the second covering and closing part (201) lies, the narrowing step having such a size that the two adjacent sections of the second covering or closing part (201) are connected in a flush manner, and the length of said narrowing step (801) in the axial direction of the flue essentially corresponds to the insertion stroke of two second inner tubular elements (2) of two adjacent flue sections and/or to the axial dimension of the press-fit terminal (701) of the sections of the first part (101) of the first outer tubular casing element (1).
A flue system as claimed in claim 24, characterized in that said second part (201) of the first outer casing element (1) ends by its two opposite longitudinal ends flush with the corresponding ends of the first part (101) respectively.
A flue system as claimed in one or more of the preceding claims, characterized in that the second part (201) of the first outer tubular casing element (1) has one or more preformed inspection apertures to be closed by corresponding doors, possibly themselves prefabricated, which apertures may coincide with closable inspection apertures formed in the second inner tubular element (2).
A flue system as claimed in one or more of the preceding claims, characterized in that the second part (201) of the first outer tubular casing element (1) has one or more prefabricated cases for housing measuring instruments, whose inner side has apertures for the wires to sensors, prefabricated or premounted in or on the second inner tubular element (2).
A flue system as claimed in one or more of the preceding claims, characterized in that it has a prefabricated chimney top end element, to be fitted in the bell joint (102) of the second inner tubular element (2) and on the connection or press-fit terminal of the first outer tubular element (1) of the top section of the flue.
A flue system as claimed in one or more of the preceding claims, characterized in that the inner tubular element (2) may have at least one transverse branched portion and/or one curved portion with a transverse branch (302), said transverse branch being turned toward the first part (101) or the second part (201) of said first outer casing element (1) and said first part (101) or said second part (201) having an aperture for the passage of said transverse branched portion or said transverse curved portion (302).
A flue system as claimed in one or more of the preceding claims, characterized in that an intermediate covering layer (7) made of an insulating material is provided between the first outer tubular casing element (1) and the second inner tubular element (2), which covering layer is shaped in such a manner as to be complementary to the outer side of the second tubular element (2) and/or to the inner side of at least a portion of the first part (101) and/or at least a portion of the second part (201) of the first outer tubular casing element (1).
A flue system as claimed in claim 30, characterized in that said intermediate insulating layer (7) is divided circumferentially into at least two or more complementary parts (107, 207) and/or longitudinally to correspond at least to the length of the flue sections or into pieces whose length is a submultiple of the length of said flue sections.
A flue system as claimed in one or more of the preceding claims, characterized in that at least the second covering or closing part (201) of the first outer casing element (1) is composed of two or more parts, that may be removably coupled by complementary interlock or press-fit and/or clamp engagement means or hinged together to oscillate about at least one axis parallel to the longitudinal axis of the flue and/or to one or more transverse axes.
A flue system as claimed in one or more of the preceding claims, characterized in that, in combination with a first outer tubular casing element (1), two or more inner tubular elements (2) are provided having equal or different diameters, some or all of them being constructed as claimed in one or more of the preceding claims.
A flue system as claimed in claim 33, characterized in that the first part (101) of the first outer casing element (1) has a cradle with two, three or more housings for two, three or more second inner tubular elements.
A flue system as claimed in one or more of the preceding claims, characterized in that at least the second covering or closing part (201) of the first tubular casing element (1) is made of metal and/or plastic and/or of a multilayer material comprising at least one metal layer and at least one plastic layer.
A flue system as claimed in one or more of the preceding claims, characterized in that the second covering or closing part (201) of the first tubular casing element (1) acts as an anchorage or support element for a finishing layer, such as a paint layer and/or a layer formed by one or more finishing panels, e.g. made of metal, plastic, concrete, or a stone material such as rock, granite, marble or the like, or at least one multilayer panel comprising at least one support layer made of plastic or concrete, and one finishing layer made of metal, plastic or a stone material such as rock, granite, marble or the like.
A flue system as claimed in one or more of the preceding claims, characterized in that the second covering or closing part (201) of the first tubular casing element (1) is provided in the form of a frame having means for removably fastening wall panels, such as through bolts, or the like.
A flue system as claimed in one or more of the preceding claims, characterized in that it is composed of at least one flue section as claimed in one or more of the preceding claims and of at least one chimney top terminal, to be fitted on the upper end of the flue section, and possibly of at least one section having a second curved inner tubular element, deflecting toward the discharge outlet of a flue gas generating device.
A method of assembling a flue system as claimed in one or more of the preceding claims and composed of at least one or more essentially identical flue sections, characterized in that the method includes the following steps:

sequentially fastening the sections of the first part (101) of the first outer tubular casing element (1) to a wall, e.g. the outer wall of a building, i.e. by placing the connection or press-fit terminals of the sections of the first part (101) , thereby forming a continuous element for housing and securing the second tubular element;

sequentially mounting the sections of the second inner tubular element (2) to the cradles (4) of the corresponding sections of the first parts (101) of the outer tubular casing element (1), i.e. fitting each of them into the bell joint (102) of the section of the inner tubular element (2) of a previous flue section, if any, and fastening it to the corresponding first part (101) in the predetermined relative position, by using the removable fastening means at the bell joint of the corresponding section of the second tubular element (2);

sequentially coupling the sections of the second covering and closing part (201) of the first outer tubular casing element (1) to the first parts (101) of said first outer tubular casing element (1).
A method as claimed in claim 39, characterized in that it includes one or more intermediate steps for inserting intermediate elements to cover the sections of the second inner tubular element.
A method as claimed in claim 39 or 40, characterized in that the sections of the second part of the tubular element (2) are pre-mounted to the sections of the first part (101) of the outer tubular casing element (1) and fastened together to the wall.