GB2097109A

GB2097109A - Ceramic elements for use in the construction of chimney ducts

Info

Publication number: GB2097109A
Application number: GB8210369A
Authority: GB
Original assignee: Pomel SA Ets
Current assignee: Pomel SA Ets
Priority date: 1981-04-08
Filing date: 1982-04-07
Publication date: 1982-10-27
Also published as: FR2503773B1; BE892786A; LU84074A1; FR2503773A1; GB2097109B; DE3212330A1

Abstract

A ceramic element for use in the construction of chimney ducts includes an outer shell (1) of generally rectangular cross-section consisting of outer and inner leaves (4, 5) separated from each other by a row of secondary cells (6), and an inner shell (2) consisting of an outer leaf (7) of generally rectangular cross-section separated from an inner leaf (10) by a further row of secondary cells (11). The element further includes at least one primary cell (3) separating each pair of adjacent faces of the inner and outer shells (1, 2), the length of each primary cell (3) being at least equal to half the length of a side (8) of the outer leaf (7) of the inner shell (2). <IMAGE>

Description

SPECIFICATION Ceramic elements for use in the construction of chimney ducts The present invention relates to elements for use in the construction of buildings, and more particu larly to ceramic elements for use in the construction of chimney ducts.

It has been known for a considerable length of time to construct the chimney ducts of buildings with super-imposed elements fabricated in baked clay. Baked clay is an ideal material for such building elements, particularly in view of its impermeability and its excellent resistance to heat. Due to recent rises in the costs of fuels, the heat exchange capacities at the heat generators have been increased, and it has therefore been necessary, in order to retain a certain temperature in the smoke emitted from said generators, to increase the ther mal resistance of the ducts. We have recently achieved this by providing elements in the form of profiled shells produced by extrusion and compris ing a plurality of leaves of baked clay each of cellular structure. Such elements have constituted an unde niable progress as regards the efficiency of heating installations.

However, in the more recent past, smoke ducts have been required to have a still higher resistance to heat transfer. In order to satisfy these new requirements it was necessary, when using ducts incorporating the aforesaid extruded shells, to stop the ducts up with a thermal insulator and then to cover this insulator with a partition so as to be able to line the duct conveniently either with a float skin or with plaster according to the external or internal face of the wall in which the duct was integrated.

It would be desirable to be able to provide a duct which avoids the necessity for the subsequent oper ations of stopping up and of erecting the partition, and which hence which would reduce construction costs.

According to the present invention there is pro vided a ceramic element for use in the construction of smoke ducts, the element comprising an outer shell of quadrilateral transverse section, said shell including inner and outer leaves separated by a row of hollow secondary cells, and an inner shell includ ing an outer leaf of quadrilateral transverse section the sides of which are parallel with and spaced from the adjacent sides of the inner leaf of the outer shell, said inner shell further including an inner leaf sepa rated from said outer leaf by a further row of secon dary cells, adjacent faces of the outer and inner shells being separated from one another by at least one primary cell the length of which, in a transverse plane through the element, is equal to at least half the length of a side of the outer leaf of the inner shell.

In such an arrangement, the outer shell acts as a partition which is automatically erected as the duct is constructed and without further complication, while the large primary cells, which can result in a minimum ofthermic bridges between the inner and outer shells, can act as housings for a heat insulating material which suppresses convection inside said cells.

Advantageously there are four primary cells, one between each pair of adjacent faces of the outer and inner shells, each primary cell having a length intermediate the length of a side of the outer leaf of the inner shell and the length of the inner leaf of the outer shell; this results in a reduction in the number of thermic bridges to a minimum, and the possibility of a unique insulating mattress for each of the sides ofthe element.

In a preferred embodiment of the invention, each primary cell is lined along its entire length with material having a high coefficient of thermal insulation and resistant to high temperatures. The lining may be performed either in the factory, or on site by the insertion of an insulator of the mineral wool type or by injection.

Preferably the inner and outer shells are axially staggered relative to one another.

By way of examples only, embodiments of the invention will now be described in greater detail with reference to the accompanying drawings of which: Figs. 1 and 2 are transverse sections through first and second double-shelled elements according to the invention, and Figs. 3a and 3b are longitudinal sections through parts of two superimposed elements such as those of Figs. 1 or 2.

Referring to Fig. 1, which is a section in a plane perpendicular to the axis of extrusion of the profile which forms an element, the illustrated element consists of an outer shell 1 and an inner shell 2 separated by large primary cells 3.

The outer shell 1 is of quadrilateral cross-section and consists of an outer leaf 4 and an inner leaf 5, said leaves being separated by a row of small secondary cells 6. It will be noted that the outer faces of the outer shell are grooved so as to permit good bonding to the plaster or the mortar, since as mentioned above, these outer shells are intended to replace a partition.

The inner shell 2 includes an outer leaf 7 of quadrilateral cross-section, the sides, such as the side 8, of which are parallel to the opposing sides, such as the side 9, ofthe inner leaf of the outer shell. The inner shell 2 further includes an inner leaf 10. The leaves 7 and 10 of the inner shell are separated buy a further row of small secondary cells 11. It will be observed that the inner leaf 10 ofthe inner shell has rounded corners. However this could be cylindrical or of quadrilateral cross-section.

The length / of a large primary cell 3 is at least equal to half the length m of a side of the outer leaf 7 of the inner shell 2. In Fig. 1, this length / is intermediate said length m and the lengthy of the inner leaf 5 of the outer shell 1. In the embodiment of Fig.

1, the large primary cells 3, as well as the element as a whole, have a 4th order symmetry about the extrusion axis 12, in that the components of the element are super-imposable by rotation through /4 about the axis 12.

The element of Fig. 2 differs from that of Fig. 1 in the arrangement and dimension ofthe large primary cells. In the element of Fig. 2, two large primary cells 14, 15 situated on opposite sides of the element each have lengths I'1, extending across the entire lengthy' of the inner leaf of the outer shell, whereas two large primary cells 16, 17 have lengths/'2 shorter than that of said cells 14, 15 and extending only across the width m' of the outer leaf of the inner shell. It will be observed that such an element has a 2nd order symmetry about its axis 18.Such an arrangement presents two advantages, namely the sides of the element containing the shorter primary cells 16, 17 can advantageously be the sides contained in the thickness ofthewall of the duct, while the othertwo sides face the open air; another advantage lies in the fact that, on leaving the die, the clay element is less likely to deform when it rests upon the sides abutting the shorter length primary cells 16 and 17.

In Figs. 3a andb, elements of Figs. 1 and 2 are shown sectioned along the central longitudinal axes, the outer shell such as 20 and the inner shell such as 21 exhibiting an axial stagger k therebetween. This stagger, which is knowperse in other types of elements, prevents sweating of the water of condensation inside the ducts. It will also be observed in these illustrations that a mattress of insulating material 22, 22' may either extend from the primary cell of one element into the corresponding primary cell of a superimposed element (Fig. 3a), or may, like the mattress 23, lie only in the cell of an associated element (Fig. 3b).

It will be noted in connection with the mattresses of insulating material that an element such as that of Fig. 2 will require mattresses of two distinct widths, which is a disadvantage compared with the element of Fig. 1, in which the large primary cells all have the same length. Lastly, it will be recalled that this insulating material may either be introduced into the element on manufacture, a case which lends itself to an arrangement such as that of Fig. 3b, or the insulating material may be supplied separately to the installer, a case which lends itself to the arrangement of Fig. 3a.

Claims

1. A ceramic element for use in the construction of smoke ducts, the element comprising an outer shell of quadrilateral transverse section, said shell including inner and outer leaves separated by a row of hollow secondary cells, and an inner shell including an outer leaf of quadrilateral transverse section the sides of which are parallel with and spaced from the adjacent sides of the inner leaf of the outer shell, said inner shell further including an inner leaf sepa rated from said outer leaf by a further row of secon dary cells, adjacent faces of the outer and inner shells being separated from one another by at least one primary cell the length of which, in a transverse plane through the element, is equal to at least half the length of a side ofthe outer leaf of the inner shell.

2. A ceramic element as claimed in claim 1 in which there are four primary cells, one between each pair of adjacent faces of the outer and inner shells, each primary cell having a length intermediate the length of a side of the outer leaf of the inner shell and the length of a side of the inner leaf of the outer shell.

3. A ceramic element as claimed in claim 1 or claim 2 in which each primary cell is lined along its full length with a heat resistant material having a high coefficient of thermal expansion.

4. A ceramic element as claimed in claim 3 in which said material is mineral wool.

5. A ceramic element as claimed in any one of claims 1 to 4 in which the inner and outer shells are axially staggered relative to one another.

6. A ceramic element for use in the construction of smoke ducts substantially as described with referpence to and as illustrated by the accompanying drawings.