WO2009010629A1

WO2009010629A1 - Protection part combination

Info

Publication number: WO2009010629A1
Application number: PCT/FI2008/050400
Authority: WO
Inventors: Janne Tanhuanpää; Tuomo Huopana
Original assignee: Rautaruukki Oyj
Current assignee: Rautaruukki Oyj
Priority date: 2007-07-17
Filing date: 2008-07-01
Publication date: 2009-01-22
Anticipated expiration: 2010-01-17
Also published as: FI20075552A0

Abstract

A protection part combination for openings, particularly for ends of air flues, such as chimneys, which protection part combination comprises a cover part (5) in which there is at least one opening (6), and at least one protection part (4) to be fastened in the cover part. In the cover part, guide elements (9) are arranged in which counter elements (13) arranged in the protection part are fittable such that the protection part (4) is movable supported by the guide elements (9) slidingly in relation to the cover part (5) between at least two positions, a first position in which the protection part (4) is at the point of the opening (6) and a second position in which the protection part (4) is moved away from the point of the opening (6). The invention also relates to the protection part (4) and the cover part (5).

Description

PROTECTION PART COMBINATION

Background of invention

The invention relates to a protection part combination according to the preamble of claim 1 for openings, particularly for ends of air flues, such as chimneys, which protection part combination comprises a cover part in which there is at least one opening and at least one protection part to be fastened in the cover part.

The invention also relates to a protection part according to claim 10 particularly for air flues, such as chimneys, which protection part is movably fastenable at the upper end of an air flue, such as a chimney, directly or by means of an intermediate part.

The invention further relates to a cover part according to claim 18, particularly for air flues, such as chimneys, which cover part comprises a cover surface part and an opening formed in it which is arranged in incidence with the opening of the flue channel.

From construction engineering, protection device combinations of an air flue or a chimney in connection with different air flues, particularly chimneys, usually guided through building roofs are known, which typically comprise a covering-like capping coming outside the air flue or the chimney, a protection cover of the end of the chimney and a chimney protection part i.e. a chimney hood to be fastened in the protection cover or directly to the chimney. On the one hand, the protection capping protects the air flue from the outside and, on the other hand, by means of it, the flue protection is connected to the roof coating and sufficient sealing is provided in the connection point of the roof and the air flue. Water accessing air flues, such as chimneys, disintegrates the inner surface of the air flues in the course of time. The disadvantage caused by water is especially great in the case of rarely heated fireplaces. The disadvantage caused can, however, be considerably diminished by installing a separate chimney hood on top of the chimney which also improves chimney ventilation.

Chimney hoods have been used for protecting the chimney and the air flue, inter alia, from the effects of weather, such as for preventing the access of water or snow in the chimney flue. The chimney hood has typically been fastened from vertical support elements on top of the chimney, whereby the protection part of the actual chimney hood is at a distance from the upper surface of the chimney. Then, flue gases are well able to be carried from the air flue between the chimney and the protection part of the hood and, on the other hand, the distance has allowed chimney sweeping without removing the chimney hood. In some chimney hoods, there is a net or equivalent to prevent litter, animals, such as birds or squirrels, from accessing the chimney flue. These nets hinder chimney sweeping, whereby the chimney hood has to be often removed for the time of sweeping or other maintenance. However, a disadvantage of known arrangements is that their fastening and removal during maintenance work, such as chimney sweeping or equivalents, is awkward and requires tools. Furthermore, removing the hood can cause dangerous situations. Also chimney hoods are known which are fastened in a projection of the chimney, such as a masonry edge, and are movable to the side. A disadvantage of these is often their difficult aesthetical fitting together with the chimney capping and the roof coating and, particularly, their durability with respect to both the corrosion caused by flue gases and thermal stress. Furthermore, some of them are not applicable to be used together with ready-made chimneys.

A considerable factor in connection with known chimney hoods is that they should fit aesthetically together with the protection capping of the chimney and also with the roof coating. Then in known arrangements, the corrosion resistance of chimney hoods, inter alia, due to load caused by flue gases, can be defective.

The object of this invention is a protection part combination suitable on top of different air flues of buildings, by means of which the disadvantages of known prior art are avoided. Another object is to provide a protection part which is easily arrangeable to be used e.g. in connection with a modular protection part combination of ready-made chimneys. A further object is to provide a protection part of a chimney the corrosion resistance of which is better than earlier and which enables easy installability. A further third object is to provide a protection part combination which is aesthetically fittable into connection with the chimney capping and the roof coating, the corrosion resistance of the chimney hood remaining better than earlier.

Brief description of invention A protection part combination according to the invention is characterised in that, in a cover part, guide elements are arranged in which counter elements arranged in a protection part are fittable such that the protection part is movable supported by the guide elements slidingly in relation to the cover part between at least two positions, a first position in which the protection part is at the point of the opening and a second position in which the protection part is moved away from the point of the opening.

Furthermore, the protection part combination according to the invention is characterised by what is stated in claims 2-9.

A protection part according to the invention is characterised by the protection part comprising a counter part for guide elements arranged at an upper end of an air flue or an intermediate part, such as a cover part.

Furthermore, the protection part according to the invention is characterised by what is stated in claims 11-17.

A cover part according to the invention, again, is characterised in that, in the cover part, guide elements are arranged supported by which a possible protection part is arrangeable to move.

Furthermore, the cover part according to the invention is characterised by what is stated in claims 19-24.

The arrangement according to the invention has numerous significant advantages. By means of the protection part combination according to the invention, an extremely maintenance-friendly arrangement is provided for protecting the ends of different openings, particularly air flues, such as the ends of chimneys. The arrangement enables protecting ready-made chimneys effectively against weather conditions. Furthermore, a unit is provided which is easily connectable to the capping of an air flue, such as the capping of a chimney. By arranging a protection plate into connection with the protection part, an arrangement with better resistance against heat and corrosion is provided, particularly into connection with chimneys. Simultaneously, it is possible to maintain the materials of the protection part and the outside of the cover part uniform. By using the edges of the cover part as the guide elements in which the counter elements of the protection part fit, an advantageous arrangement is provided for arranging a movable protection part. The protection part is quickly fastenable in the cover part. The mutual immobility of the protection part and the cover part can be arranged, if required, by quick fastening, such as by a cotter. The invention also enables an easy way to arrange means for preventing the access of litter and animals in the air flue. By forming flaps or projections or equivalents in the protection plate or the protection part, said means are provided quickly. The combination according to the invention offers a possibility to modularly form required protection parts e.g. in chimneys comprising several air flues or equivalents. Several protection parts can be used with one cover part. It is also possible to form different protection parts to be used with one cover part. The protection part according to the invention can also be used in connection with other chimneys than solely with chimneys provided with a cover part according to the invention. Then, the improved resistance of corrosion and thermal stress is a considerable improvement compared to earlier, without compromising matters of appearance. Furthermore, a possibility combined to the protection plate to provide protection means for preventing the access of litter, animals, such as birds, in the protected opening has been made easily implementable in relation to known arrangements. The cover part comprises a collar which prevents the access of water in the air flue. In addition, a fastening collar is formed in the cover part which collar is easily bringable from a transport position to an operating position. Furthermore, openings have been formed in the fastening collar from which the cover part is fastenable in the capping of the air flue, forming a moving connection. The arrangement according to the invention is easily installable and is aesthetically suitable together with the roof coating and the chimney capping. Also, the processibility of the parts used in the combination is good.

Brief description of figures

In the following, the invention will be described in detail by means of an example with reference to the accompanying drawings in which

Fig. 1 shows a protection part combination according to known prior art in connection with the end of a chimney,

Fig. 2 shows an embodiment of an apparatus according to the invention, the protection part in a first position, Fig. 3 shows an embodiment of an apparatus according to the invention, the protection part in a second position,

Fig. 4 shows a detail of an apparatus according to the invention,

Fig. 5 shows another embodiment of an apparatus according to the invention,

Fig. 6 shows a further embodiment of an apparatus according to the invention,

Fig. 7 shows a detail of a protection plate used in an embodiment of an apparatus according to the invention,

Fig. 8 shows a blank of a protection plate of an embodiment of an apparatus according to the invention, and

Fig. 9 shows a yet further embodiment of an apparatus according to the invention.

Detailed description of invention

Fig. 1 shows a protection part combination according to known prior art in connection with a chimney. The chimney is designated with reference number 1. Inside the chimney goes vertically an air flue 2. At the upper end of the chimney, there is a flue opening 3. At the upper end of the chimney is arranged a cover part 5 in which there is an opening at the point of the flue opening 3. On top of the cover part at the point of the flue opening 3 and the opening 6 is conventionally arranged a protection part 4 i.e. a chimney hood with fastening means, such as screws or bolts, in the cover part 5.

Figs. 2 and 3 show an embodiment of a protection part combination of an opening, such as an end of an air flue, according to the invention. The figures show the cover part 5 to be arranged at the upper end of the air flue, such as a chimney, in which is formed the opening 6 most suitably at the point of the flue opening of the flue channel and the protection part 4 i.e. the hood part movable with respect to the cover part 5 which in a first position i.e. a protective position is at the point of the opening 6 of the cover part (Fig. 2). In Fig. 3, the protection part 4 has been moved from covering the opening of the cover part to a second position. Figs. 2 and 3 do not show the air flue, such as a chimney, for clarity.

The invention thus relates to a protection part combination for openings, particularly for ends of air flues, such as chimneys, which protection part combination comprises a cover part 5 in which there is at least one opening 6, and at least one protection part 4 to be fastened in the cover part. In the cover part, guide elements 9 are arranged in which counter elements 13 arranged in the protection part are fittable such that the protection part 4 is movable supported by the guide elements 9 slidingly in relation to the cover part 5 between at least two positions, a first position in which the protection part 4 is at the point of the opening 6 and a second position in which the protection part 4 is moved away from the point of the opening.

The guide elements 9 of the cover part 5 and the counter elements 13 of the protection part 4 are form-locked to each other at least in one direction transverse in relation to the moving direction of the protection part. Then, the protection part stays well in place and can only move along the guide elements.

The protection part combination further comprises quick fastening means 15 for the mutual locking of the protection part 4 and the cover part 5. The quick fastening means comprise e.g. a cotter element which is passable in openings or equivalents formed in the parts.

The protection part 4 further comprises a protection plate 14 which is arranged between the cover part 5 and the protection part 4 at least at the point of the opening 6 of the cover part when the protection part 4 is in the first position.

The protection part combination can comprise means 16, 22, 23 for preventing the access of animals or harmful objects in the opening 6 from outside. These means 16 typically comprise wall parts 20, 23 provided with openings 23, flaps or projections 16 or equivalents.

The protection part can be formed of desired size. In the embodiment of Figs. 2 and 3, the protection part 4 extends to a part of the length of the cover part 5 in the direction of the guide elements 9. In the embodiment of Figs. 2 and 3, the protection part 4 is only somewhat wider than the diameter of the opening 6. Naturally, the protection part 4 can also be wider and it can be larger than the cover part in the direction of the guide elements.

The protection part combination can also comprise several protection parts 4, 4' arranged in the cover part 5, as shown in Fig. 5.

The protection part combination 4, 5 is connectable from its lower part to the upper part of the protective casing of the air flue (not shown), such as to the capping of the chimney. This is not shown in the figures but will be described later in more detail.

The protection part 4 is shaped such that the protection part extends vertically at a distance from the cover part 5 at least at the point of the opening 6 of the cover part. For functionality, this is essential, at least in the embodiment intended for a chimney.

The cover part 5 comprises a cover surface part 7 and an opening 6 formed in it which is arranged in incidence with the opening of the flue channel. In the cover part, a collar 8 is arranged around the opening 6 which collar extends at a distance upwards from the surface of the cover part.

In the cover part 5, guide elements 9 are arranged supported by which a possible protection part is arrangeable to move. The guide elements 9 are formed of the edge area of the cover part. According to an advantageous embodiment of the invention, the opposite edge areas 9 of the cover part 5 are guide elements. The cover part 5 comprises a fastening collar part 11 which extends at a distance from the fastening plane of the collar part, such as from the plane of the end of the air flue, downwards. In the collar part 11 is formed an opening or a gap 12 from which the collar part 5 is fastened in the protective casing of the air flue, particularly its upper part, which enables the longitudinal mutual motion of the gap between the cover part and the casing. The fastening collar 11 comprises at least one fold point from which the walls of the collar are folded inwards in the storage position and are openable at the installation site to the fastening position.

Next, an embodiment of the cover part 5 will be presented. The cover part can be manufactured of one part, sheet material, e.g. plate material. The cover part 5 comprises a cover surface part 7 in which is formed an opening 6 for the opening of the air flue of the chimney. Around the opening 6 of the cover part, there is a collar 8, whereby the edge of the opening 6 extends at a distance from the cover surface part 7 outwards. The height of the collar 8 from the surface plane of the cover surface part varies in accordance with the embodiment. A typical height is about 10-50 mm, advantageously about 20-25 mm. In the cover part 5, there is an edge area 9 which encircles the cover surface part 7. At a distance from an outer edge 10 of the cover part 5 inwards, on the opposite side of the cover part 5 in relation to the cover surface part 7, there is a fastening collar 11. The cover part 5 is typically intended to be set at the upper end of the air flue, such as a chimney, whereby the fastening collar 11 extends at a distance downwards in relation to the upper surface of the chimney. The fastening collar 11 extends in the casing part of the capping of the chimney which encircles the chimney at least partially. The cover part 5 is intended to be connected to the casing of the capping, e.g. by fastening means. In the cover part 5, in its fastening collar 11 , is formed at least one opening or gap 12, e.g. an elongated, vertical opening, from which the cover part 5 is fastened in the casing of the capping of the chimney with fastening means, typically with short screws. The elongated opening 12 enables the mutual motion between the cover part 5 and the capping or other suitable fastening point. Then, e.g. possible motions of the structures of a building, e.g. the setting of a log house, in relation to the chimney will be considered.

The edge area 9 of the cover part 5 extends at a distance from the fastening collar 11 outwards. The edge area 9 slopes away from the collar 8 and the opening 6.

The fastening collar 11 is formed e.g. by cutting and bending one blank sheet. The cover part 5 can be manufactured e.g. at a sheet metal workshop where several work stages, cutting, punching, bending and edging can be performed at the same time.

The protection part 4 i.e. the hood part is arranged movably with respect to the cover part 5. The protection part 4 comprises counter elements 13 which are arranged to fit with the guide elements 9 of the cover part, such as a protruding edge area. The counter elements 13 comprise at least one first counter part coming against the upper surface of the cover part and at least one second counter part coming against the lower surface of the edge area. There are typically at least two of the guide elements 9 of the cover part, one on each side of the opening of the cover part. The counter elements 13 of the protection part are formed of the bent edge area, whereby the edge area extends around the equivalent edge 10 of the cover part from above to below it. The edge area of the protection part can be uniform or it can be formed of several projections which are bent to form mating surfaces for the guide surfaces of the cover part.

The protection part 4 is movably arranged supported by the guide elements 9 of the cover part 5, particularly slidingly. Thus, it is possible to move the protection part, if required, away from top of the opening 6 e.g. for maintenance work, whereby the edge areas of the cover part function as guide elements supported by which the counter elements 13 of the protection part and the protection part 4 move. In the embodiment in question, the protection part is fastened supported by the edges of the cover part so that it is easily movable sidewards. Also other fastening arrangements can be considered by means of which the protection part is movable sidewards. An alternative arrangement is to bend the edges of the cover part upwards around the edges of the protection part, whereby the edges of the cover part form a guide groove in which the edges of the protection part are able to move.

On the side of the cover part of the protection part 4, a protection plate 14 is arranged. The purpose of the protection plate is to prevent or at least minimise the corrosion load and thermal stress caused by flue gases and heat coming via the opening of the cover part 6, such as the air flue of the chimney, to the protection part 4. The protection plate 14 can be of some suitable material having good corrosion resistance properties. Some suitable materials are corrosion-resistant metals, such as galvanised steel or stainless or acid-proof steel. The shape of the protection plate is dependent on the target of application. It can be a straight sheet or curved or otherwise suitably shaped.

Fig. 6 shows another embodiment of the protection part combination and the protection part 4, in a protection plate 14 in connection with which are formed projections 16 which are bendable in a way shown by the figure e.g. for the intention of preventing the access of animals and litter in the opening 6 of the cover part 5 and further in the air flue. It can also be considered that the projections 16 function as heat exchanger surfaces thus minimising the thermal stress directed at the protection part. The shape of the projections 16 can vary in accordance with the embodiment. The projections advantageously extend around the collar 8 of the opening 6 of the cover part, outside of it, whereby according to an advantageous embodiment they support themselves on the outer surface of the collar 8. Then, it can be considered that the projections 16 can also be used for locking the protection part in the cover part at least in the protective position.

Figs. 7 and 8 show an embodiment of a protection plate 14 of the protection part 4. Fig. 8 shows a top view as a blank and Fig. 7 axonometrically. In Fig. 8, the blank comprises in the centre a uniform area, which is circular, which corresponds to the shape of the opening 6 of the cover part 5. From it, projection blank fields 16 are radially formed divided in the circle of the uniform circular area. The projections can be left in the position of Fig. 8 and, if desired, they can be bend into view e.g. in the position of Fig. 7. In the projections, there are openings 18.

In Fig. 7, the projections 16 are bent to extend at a distance from the surface of the protection plate 14. In Fig. 7, the projections extend upwards but, when set in place, the projections of the protection plate extend downwards i.e. towards the cover part as in Fig. 6.

In the embodiment of Figs. 7 and 8, at the corners of the protection plate there are bevels 24 which facilitate installing the plate 14 and, on the other hand, the passage of flue gases. Additionally, they save material.

The protection plate is arranged according to Fig. 6 supported by support surfaces 21 formed in the hood part. The protection plate is thus mainly at a distance from the lower surface of the protection part. Between the protection plate and the lower surface of the protection part, there is a space 25 which minimises the thermal stress directed at the protection part 4.

The shape of the protection plate 4 and the shape and size of the projections 16 to be bend from it can vary in accordance with the embodiment.

In the embodiment of Figs. 2 and 3, the protection plate 14 is formed curved. Then, it is able to support the protection part 4 e.g. against the load caused by snow gathered on top of the protection part. A protection part 4, particularly for air flues, such as chimneys, which protection part 4 is movably fastenable at the upper end of an air flue, such as a chimney, directly or by means of an intermediate part. In the protection part 4, a protection plate 14 is arranged on the side of the flue opening intended to be covered. The actual protection part 4 is formed of one piece. The protection part 4 comprises a counter part 13 for guide elements 9 arranged at then upper end of an air flue or an intermediate part, such as a cover part 5.

The counter part 13 is form-locked in the guide elements 9 of the upper end of the air flue or the intermediate part, such as the cover part, at least in one direction transverse with respect to the guide elements. In the protection part 4 is formed a support surface 21 supported by which the protection plate 14 is arranged.

The protection plate 14 can comprise flaps, projections 16 or equivalents which extend towards the upper surface of the upper end of the air flue or the intermediate part, such as the cover part 5. The protection plate is typically of corrosion-resistant material.

The upper surface of the protection part 4 is formed level or sloping towards edges 10.

The invention also relates to a cover part 5, particularly for air flues, such as chimneys, which cover part comprises a cover surface part 7 and an opening 6 formed in it which is arranged in incidence with the opening of the flue channel. In the cover part, a collar 8 is arranged around the opening 6 which collar extends at a distance upwards from the surface of the cover part. In the cover part, guide elements 9 are arranged supported by which a possible protection part 4 is arrangeable to move.

According to an embodiment, the guide elements 9 are formed of the edge area of the cover part. Typically, the opposite edge parts of the cover part are guide elements. It can be considered that all four edge parts of the cover part can function as guide elements. If the cover part is quadratic, the protection part can then be fitted movably with both two opposite guide elements. This facilitates installation.

The cover part 5 comprises a fastening collar part 11 which extends at a distance from the fastening plane of the collar part, such as from the plane of the end of the air flue, downwards. In the collar part is formed a gap 12 from which the collar part 5 is fastened in the protective casing of the air flue, particularly its upper part, which enables the longitudinal mutual motion of the gap between the cover part and the casing.

The fastening collar 11 comprises a fold point from which the walls of the collar are folded inwards in a storage position and are openable at the installation site to a fastening position by bending them in the opposite direction outwards.

The protection part is typically manufactured of coated sheet steel the thickness of which can vary in accordance with the embodiment. In an embodiment, typical thickness is 0.7-0.9 mm. The cover part can be of the same material with the protection part. Typically, also the capping of the chimney can be of the same material. Then is provided an aesthetically good unit which does not necessarily require surface treatment.

It is obvious to those skilled in the art that the invention is not limited to the embodiments described above, but it may be varied within the scope of the enclosed claims. Thus, it is also possible to use the protection part combination in connection with other openings than air flues, such as chimneys. When necessary, the features possibly described in this specification together with other features may also be used separately from each other.

Claims

1. A protection part combination for openings, particularly the ends of air flues, such as chimneys, which protection part combination comprises a cover part (5) in which there is at least one opening (6) and at least one protection part (4) to be fastened in the cover part, characterised in that in the cover part are arranged guide elements (9) in which counter elements (13) arranged in the protection part are fittable such that the protection part (4) is movable supported by the guide elements (9) slidingly in relation to the cover part (5) between at least two positions, a first position in which the protection part (4) is at the point of the opening (6) and a second position in which the protection part (4) is moved away from the point of the opening.

2. A protection part combination according to claim 1, characterised in that the guide elements (9) of the cover part (5) and the counter elements (13) of the protection part (4) are form-locked to each other in at least one direction transverse in relation to the moving direction of the protection part (4).

3. A protection part combination according to claim 1 or 2, characterised in that the protection part (4) further comprises a protection plate (14) which is arranged between the cover part (5) and the protection part (4) at least at the point of the opening (6) of the cover part when the protection part (4) is in the first position.

4. A protection part combination according to any one of claims 1-3, characterised in that the protection part combination comprises means (16, 22, 23) for preventing the access of animals or harmful objects in the opening (6) from outside.

5. A protection part combination according to claim 4, characterised in that the means (16) comprise wall parts (20, 23) provided with openings (23), flaps or projections (16) or equivalents.

6. A protection part combination according to any one of claims 1-5, characterised in that the combination further comprises quick fastening means (15) for the mutual locking of the protection part (4) and the cover part (5).

7. A protection part combination according to any one of claims 1-6, characterised in that the protection part (4) extends to a part of the length of the cover part (5).

8. A protection part combination according to any one of claims 1-7, characterised in that the protection part combination comprises several protection parts (4, 4') arranged in the cover part (5).

9. A protection part combination according to any one of claims 1-8, characterised in that the protection part combination is connectable from its lower part to the upper part of a protective casing of an air flue, such as a capping of a chimney.

10. A protection part (4), particularly for air flues, such as chimneys, which protection part (4) is movably fastenable at the upper end of an air flue, such as a chimney, directly or by means of an intermediate part, characterised in that the protection part (4) comprises a counter part (13) for guide elements (9) arranged at the upper end of the air flue or the intermediate part, such as a cover part (5).

11. A protection part according to claim 10, characterised in that the actual protection part (4) is formed of one piece.

12. A protection part according to claim 10 or 11, characterised in that in the protection part (4) is arranged a protection plate (14) on the side of the flue opening intended to be protected.

13. A protection part according to any one of claims 10-12, characterised in that the counter part (13) is form-locked in the guide elements (9) of the upper end of the air flue or the intermediate part, such as the cover part, in at least one direction transverse to the guide elements.

14. A protection part according to any one of claims 10-13, characterised in that in the protection part (4) is formed a support surface (21) supported by which the protection plate (14) is arranged.

15. A protection part according to any one of claims 10-14, characterised in that the protection plate (14) comprises flaps, projections (16) or equivalents which extend towards the upper surface of the upper end of the air flue or the intermediate part, such as the cover part (5).

16. A protection part according to any one of claims 10-15, characterised in that the protection plate (14) is of corrosion-resistant material.

17. A protection part according to any one of claims 10-16, characterised in that the upper surface of the protection part (4) is formed level or sloping towards edges (10).

18. A cover part (5), particularly for air flues, such as chimneys, which cover part comprises a cover surface part (7) and an opening (6) formed in it which is arranged in incidence with the opening of the flue channel, characterised in that in the cover part are arranged guide elements (9) supported by which a possible protection part is arrangable to move.

19. A cover part according to claim 18, characterised in that in the cover part (5) is arranged around the opening (6) a collar (8) which extends at a distance from the surface of the cover part upwards.

20. A cover part according to claim 18 or 19, characterised in that the guide elements (9) are formed of the edge area of the cover part.

21. A cover part according to any one of claims 18-20, characterised in that the opposite edge parts of the cover part are guide elements.

22. A cover part according to any one of claims 18-21 , characterised in that the cover part comprises a fastening collar part (11) which extends at a distance from the fastening plane of the collar part, such as the plane of the end of the air flue, downwards.

23. A cover part according to any one of claims 18-22, characterised in that in the collar part is formed a gap (12) from which the collar part (5) is fastened in the protective casing of the air flue, particularly its upper part, which enables the longitudinal mutual motion of the gap between the cover part and the casing.

24. A cover part according to any one of claims 18-23, characterised in that the fastening collar (11) comprises a fold point from which the walls of the collar are folded inwards in a storage position and are openable at the installation site to a fastening position by bending them in the opposite direction.