GB2159934A - Chimney flues - Google Patents

Abstract

A flue pipe assembly for use within or, as shown, at the outlet of a chimney stack comprises an inner pipe (7), e.g. of fire clay material, and an outer pipe (8), e.g. of stainless steel, between which is mounted an expansion accommodating member (10), e.g. of corrugated aluminium, to accommodate expansion and contraction of the inner pipe (7) within the structural member, e.g. stack coping, in which the assembly is mounted. A top pipe (11) of fire clay material may be mounted on the outer pipe (8) to prevent the penetration of rain and moisture into the gap between the pipes (7) and (8), or the inner pipe may be extended beyond the outer pipe and flanged to cover the gap. The outer pipe (8) may alternatively be of fireclay or asbestos, and the member (9) could be of fibreglass or plastics. <IMAGE>

Description

SPECIFICATION Improvements in and Relating to Chimney Flues The present invention relates to a flue pipe and in particular to a flue pipe forming the outlet from a chimney stack.

In general, chimney stacks are topped with a coping to prevent the ingress of moisture. A flue outlet pipe extends out through an opening in the coping, and it is necessary to tightly cast the coping around the outlet flue pipe to prevent moisture penetration down through the stack. This causes problems should a chimney fire break out in the chimney. During a fire the top free portion of the flue outlet pipe can expand freely however, the portion of the flue outlet pipe bound by the coping cannot expand. This leads to cracking and subsequent breaking of the outlet flue pipe and in many cases cracking and breaking of the coping andlorthe chimney stack itself. Once eitherthe outlet flue pipe or the coping or chimney stack crack or break, moisture can then penetrate down through the stack.This it will be appreciated is a considerable problem, particularly, in houses, buildings or the like.

There is therefore a need for a flue pipe to overcome this problem.

The present invention is directed towards providing such a flue pipe.

According to the invention there is provided a flue comprising an inner elongated pipe, and an outer expansion accommodating member on the outer surface of the inner pipe to accommodate expansion of the inner pipe in an opening of a structural member.

In one embodiment of the invention an outer pipe extends over at least portion of the length of the inner pipe, and the expansion accommodating member is provided between the inner and the outer pipes.

In another embodiment of the invention the expansion accommodating member is an elongated member and extends at least partly over the length of the inner pipe.

Preferably, the expansion accommodating member extends substantially but not quite around the inner pipe. Advantageously, the expansion accommodating member is of corrugated transverse cross-section.

In a further embodiment of the invention a radial flange extends around and outwardly of the inner pipe.

Preferably, the outer diameter of the radial flange is at least equal to the outer diameter of the outer pipe. Advantageously, the outer diameter of the radial flange is greater than the outer diameter of the outer pipe.

In a still further embodiment of the invention the inner pipe is provided in two longitudinal portions adapted to be joined together.

Preferably the flue pipe is provided in two longitudinal portions adapted to be joined together.

Advantageously, the flue pipe is adapted to form the flue outlet pipe for a chimney stack.

Additionally the invention provides an expansion accommodating member for use with the flue pipe.

Further, the invention provides a chimney stack incorporating the flue pipe.

The invention will be more clearly understood from the following description of some preferred embodiments thereof given by way of example only with reference to the accompanying drawings in which: Fig. 1 is a perspective view of a flue pipe according to the invention.

Fig. 2 is a partly cut away perspective view of the flue pipe of Fig. 1, Fig. 3 is a sectional elevational view of the flue pipe of Fig. 1, in use, Fig. 4 is a sectional plan view of the flue pipe of Fig. 1 on the line lV-IV of Fig. 3, Fig. 5 is a partly cut away perspective view of a flue pipe according to another embodiment of the invention, Fig. 6 is a sectional elevational view of the flue pipe of Fig. 5, Fig. 7 is a partly cut away perspective view of a flue pipe according to another embodiment of the invention, Fig. 8 is a sectional elevational view of the flue pipe of Fig. 7, Fig. 9 is a partly cut-away perspective view of a flue pipe according to another embodiment of the invention, Fig. 10 is a cross-sectional view of the flue pipe of Fig. 9, Fig. 11 is a sectional elevational view of the flue pipe of Fig. 9 in use, Fig. 12 is portion of a flue pipe according to another embodiment of the invention, and Fig. 13 is a perspective view of another portion of a flue pipe according to another embodiment of the invention.

Referring to the drawings and initially to Figs. 1 to 4 thereof there is illustrated a flue pipe according to the invention indicated generally by the reference numeral 1. In this case, the flue pipe is an outlet flue pipe for extending through an opening 2 in a coping 3 of a chimney stack 4, see Fig. 3. The flue pipe 1 comprises an inner pipe 7 of fire clay material and an outer pipe 8 of stainless steel extending substantially the length of the inner pipe 7. An expansion accommodating member in this case a member 9 of corrugated aluminium extends between the inner and outer pipes 7 and 8. As can be seen in Fig. 2 the expansion accommodating member 9 does not extend completely around the inner pipe 7. The longitudinal edges 10 are spacedapart to accommodate heat expansion of the member 9.It is envisaged that in practice the gap between the edges 10 will be in the order of 25 mm for a 290 mm diameter flue. The expansion accommodating member 9 and the outer pipe 8 extend almost the length of the inner pipe 7 but stop just short at 6 to accommodate the connecting flange of a lowerflue pipe 18 in the stack 4, see Fig.

3.

A top pipe 11 of fire clay material is provided at the top end of the flue pipe 1. A portion 12 of the top pipe 11 as can be seen extends beyond the inner and outer pipe 7 and 8. The portion is of reduced diameter and as can be seen the internal diameter of the portion 12 is less than the internal diameter of the inner pipe 7. Thus, the top pipe 11 prevents rainwater penetrating between the inner and outer pipes 7 and 8. The bottom portion 15 of the top pipe 11 is inwardly relieved so that the outer lower peripheral 16 acts as a drip means to cause water to drip off the outer surface of the top pipe 11 onto the coping 3. Annular reinforcing bands 17 of copper wire are cast integrally in the second outer pipe 11.

In use, the chimney stack 4 is constructed in conventional fashion with flue pipes 18 set in a weak filling of lime and sand mortar 19 between the brickwork 20. The flue outlet pipe 1 is set on the top flue pipe 18 as illustrated in Fig. 3 and the coping 3 is then cast around the flue pipe 1 so that the opening 2 is tightly cast onto the outer pipe 8 of the flue 1.

Accordingly, should a chimney fire break out the inner pipe 7 expands and the expansion is evenly accommodated over the length of the pipe 7 by the expansion accommodating member 9. On cooling the inner pipe 7 contracts and this is also accommodated by the member 9. Thus, both expansion and contraction of the inner pipe 7 is permitted evenly over the entire length of the inner pipe 7 and accordingly cracking is avoided.

In the construction of the stack 3 a damp proof course indicated by the reference numerals 21 may be provided between the coping 3 and the brick work 20 of the stack 4. Such constructions of stacks will be well known to those skilled in the art.

Referring now to Figs. Sand 6 there is illustrated a flue outlet pipe indicated generally by the reference numeral 30. In this case the flue outlet pipe 30 comprises an inner pipe 31 and an outer pipe 32 both of fire clay material. An expansion accommodating member 33 of aluminium substantially similar to the member 9 of the flue pipe 1 is provided between the inner and outer pipes 31 and 32. A similar gap is left between the edges 34 of the member 33 as is left between the edges 10 of the member 9. A radial flange 36 extends from the inner pipe 31 and beyond the outer pipe 32 to prevent the ingress of moisture between the inner and outer pipes 31 and 32. An outer peripheral ring 37 acts as a drip means to cause water to drip off from the flange 36 before it reaches the outer pipe 32.As can be seen in Fig. 6 the outer pipe 32 and the expansion member 33 are substantially the same length and extend almost the length of the inner pipe 31 thus stopping short at 38.

In use this flue outlet pipe 30 is mounted in the coping of a stack in a substantially similar fashion to the flue pipe 1. The flue outlet pipe 30 is mounted on the top flue pipe in the stack and the coping is then cast around the outer pipe 32. Needless to say, in certain cases it will be appreciated that a pre-cast coping could be used in which case the opening 2 in the coping would be tightly filled with mortar or grouting.

Referring now to Figs. 7 and 8 there is illustrated a flue pipe according to a further embodiment of the invention which is indicated generally by the reference numeral 40. This flue pipe is for use in the stack rather than as an outlet pipe. It is envisaged that the flue in a stack would be constructed from a plurality of pipes 40, or in certain cases only the first few flue pipes from the fireplace would be provided by the flue pipe 40. Essentially, this flue pipe is substantially similar to that just described with reference to Figs. 5 and 6 and similar reference numerals are used to identify similar components.

The main difference between this flue pipe 40 and the flue pipe 30 is that the flange 36 forms a female connection member 41 to engage the inner pipes 31 and the expansion accommodating member 33 of the next pipe up. It can be seen that the expansion accommodating member 33 extends substantially the length of the inner pipe while the outer pipe 32 and the expansion accommodating members stop short of the inner pipe 31 to accommodate the female connecting member 41 of the next adjacent pipe.

In use, as the chimney stack is being constructed the flue pipes 40 are mounted in the stack. By virtue of the fact that the expansion accommodating member accommodates expansion of the inner pipe 32 it is envisaged in most cases that the need for a filling of weak lime and sand mortar may be dispensed with in the construction of stack.

Referring now to Figs. to 11 there is illustrated a flue outlet pipe according to a still further embodiment of the invention indicated generally by the reference numeral 50.

In this case the flue outlet pipe 50 comprises an inner pipe 51 of fire clay material and an outer pipe 52 of asbestos material. An expansion accommodating member 53 in this case provided by fibreglass material is mounted between the inner and outer pipes 51 and 52 and extends completely around the inner pipe 51. As can be seen the outer pipe 52 and the member 53 extends over only portion of the length of the pipe. At the lower end 54 both the member 53 and the outer pipe 52 stop short of the inner pipe 51 so that the flue 50 can accommodate a female connecting portion 55 of the top flue 56 in a stack 57 (see Fig. 11). A radial flange 58 extends around the inner pipe 51. A downwardly projecting ring 59 from the flange 58 acts as a drip means to cause water run-off from the inner pipe 51 in use. As can be seen the outer pipe 52 and the expansion accommodating member 53 extend to the flange 58.

In use, brickwork 60 is built up and the flues 56 are set in a weak lime and sand mortar. The outlet flue 50 is set in the female connecting portion 55 of the top flue 56 and a coping 61 is cast around the outlet flue pipe 50 so that the coping tightly engages the outer pipe 52.

Referring now to Fig. 12 there is illustrated portion of a flue outlet pipe according to a still further embodiment of the invention. In this case the portion is identified by the reference numeral 70. As can be seen the portion 70 is a half portion of the inner pipe 51 of the flue outlet pipe 50. In this case, the inner pipe 51 is formed in two half portions 70 which are joined together to form the inner pipe 51.

A particular advantage of having the inner pipe formed in two halves is that should the inner pipe crack in the event of an extremely severe fire the inner pipe 51 can readily easily be replaced by inserting two half portions 70 into the expansion member 53.

Referring now to Fig. 13 there is provided a portion of an outlet flue pipe also according to a further embodiment of the invention. This portion is identified by the reference numeral 80 and as can be seen is substantially similar to the portion 70. The main difference between this portion and the portion 70 is that rebates 81 are formed on mating surfaces 82 of thetwo halves to join the two half portions 80. As can be seen in Fig. 13 the rebates are formed so that all half portions are identical and by putting any two half portions together they will always mate.

It will be appreciated that the main advantage of the flue pipes according to the invention is that by virtue of the fact that they incorporate an expansion accommodation member there is virtually no danger of the inner pipe cracking. Thus, the cracking of the flue pipe is avoided and subsequent cracking of the coping and/or chimney stack. Thus, the flue pipes according to the present invention have considerable advantages over flue pipes known heretofore, both flue pipes and flue outlet pipes.

A further advantage of the flue pipes according to the present invention is that should the inner pipe crack, for example, in the event of a very serious fire or through age or the like, then the inner pipe can readily easily be replaced with a new pipe by merely sliding out the broken pipe and sliding in a new inner pipe. This it will be appreciated overcomes the need to re-grout the pipe is around the coping. Thus, once the inner pipe has been replaced there should be no danger of leaks afterwards. Needless to say, where it is desired to replace the expansion accommodating member this can also readily easily be done.

It is envisaged that while in the embodiment of the invention described with reference to Figs. 1 to 4 the outer pipe has been described as being of steel it could if desired be of fire clay material also. Indeed, it is envisaged that where it is of fire clay material the top pipe could be formed integrally with it.

It is also envisaged that while in the embodiments of the invention described with reference to Figs. 1 to 6 expansion accommodating members of aluminium have been described any other suitable material besides aluminium could be provided. It will also of course be appreciated that other crosssections besides corrugation could be used.

Furthermore, it is envisaged in certain cases that instead of using metal of corrugated cross-section the expansion accommodating member could be provided by fibre-glass as is described with reference to Figs. 9 to 11. Furthermore, other suitable resilient materials, either plastics materials or the like could be used. It is however, advisable thatthe expansion accommodating member should be of a relatively heat resisting material.

Further, it is envisaged that where the expansion accommodating member is of corrugated metal it could be provided in a plurality of longitudinal portions spaced-apart from each other around the periphery of the inner pipe. Further, it will be appreciated that in certain cases the outer pipe may be dispensed with altogether.

It will also be appreciated that the inner pipe, although in all cases has been described as being of fire clay material, any other suitable materials could be used. Additionally, it will be appreciated that the inner and outer pipes where manufactured of fire clay, could if desired be reinforced by annular and/or longitudinal reinforcing members of steel, brass, copper or the like. Further, it will be appreciated that while various drip means has been described in most of the flues these could be dispensed with if desired or other construction of drip means could be used. It will also be appreciated that other construction of inner and outer pipes could be used.

It is also envisaged that while the outer pipe in all cases has been described as being formed in one piece it could be formed in two halves split longitudinally or it could be formed by a plurality of portions split longitudinally. Additionally, it is envisaged that while the inner pipe has been described as being formed in two halves in Fig. 12 and 13 the inner pipe could be formed in any number of portions split longitudinally.

Furthermore, it is envisaged that the expansion accommodating member could be formed in a plurality of portions split longitudinally. Needless to say, where the portions are split longitudinally they could be joined together by any suitable joining means, for example, the abutting surfaces may be flat as illustrated in Fig. 12 or rebated as illustrated in Fig. 13 or, for example, they may be tongued and grooved or any other construction could be used.

It is also envisaged that in the case of all the flue pipes the outer pipe could be of any material besides stainless steel, fire clay material or asbestos, as could the inner pipe.

Further, the expansion engaging member could be provided by a polystyrene, polyurethane or any other plastics material.

It is also envisaged that while in the case of the outlet flue pipes described with reference to Figs. 5 and 6 and Figs. 9 to 13 have been described with a radially extending flange to act as a weather shield to prevent the penetration of rain into the flue pipe any other suitable weather shield arrangement could be provided.

Additionally, it is envisaged that while all the flues have been described as being of circular crosssection they could be of any other desired cross section, for example, square, triangular, hexagonal or the like. Indeed, it is also envisaged that the flues may taper from bottom to top.

Claims (39)

1. A flue pipe comprising an inner elongated member, and an outer expansion member on the outer surface of the inner pipe to accommodate expansion of the inner pipe in an opening of a structural member.

2. Aflue pipe as claimed in Claim 1 in which an outer pipe extends over at least portion of the length of the inner pipe and the expansion accommodating member is provided between the inner and the outer pipes.

3. A flue pipe as claimed in Claim 1 or Claim 2 in which the expansion accommodating member is an elongated member and extends at least partly over the length of the inner pipe.

4. Aflue pipe as claimed in any preceding claim in which the expansion accommodating member extends almost the entire length of the inner pipe.

5. Aflue pipe as claimed in Claim 5 in which the expansion accommodating member extends substantially the entire length of the inner pipe.

6. A flue pipe as claimed in any preceding claim in which the expansion accommodating member extends substantially but not quite around the inner pipe.

7. Aflue pipe as claimed in Claim 7 in which the two longitudinal edges of the expansion accommodating member are spaced-apart to accommodate circumferential expansion of the expansion accommodating member.

8. Aflue pipe as claimed in Claim 1 in which the expansion accommodating member is provided by a resilient member.

9. Aflue pipe as claimed in any preceding claim in which the expansion accommodating member is of corrugated transverse cross-section.

10. A fiue pipe as claimed in any preceding claim in which the expansion accommodating member is of metal material.

11. Aflue pipe as claimed in Claim 10 in which the expansion accommodating member is of corrugated aluminium.

12. Aflue pipe as claimed in any of Claims 1 to 9 in which the expansion accommodating member extends entirely around the inner pipe.

13. Aflue pipe as claimed in any of Claim 1 to 9 or Claim 10 in which the expansion accommodating member is of a plastics material.

14. Aflue pipe as claimed in any of Claims 1 to 9 or Claim 12 in which the expansion accommodating member is of fibreglass material.

15. Aflue pipe as claimed in any preceding claim in which a radial flange extends around and outwardly of the inner pipe.

16. Aflue pipe as claimed in Claim 15 in which the outer diameter of the radial flange is at least equal to the outer diameter of the outer pipe.

17. Aflue pipe as claimed in Claim 16 in which the outer diameter of the radial flange is greater than the outer diameter of the outer pipe.

18. Aflue pipe as claimed in Claim 20 in which a ring extending around the lower side of the radial flange acts as a drip means.

19. Aflue pipe as claimed in any of Claims 15 to 18 in which the outer pipe extends up to the radial flange.

20. Aflue pipe as claimed in Claim 19 in which the outer pipe extends from the radial flange to an end of the inner pipe.

21. A flue pipe as claimed in Claim 20 in which the radial flange is provided intermediate the ends of the inner pipe.

22. A flue pipe as claimed in Claim 20 in which the radial flange is provided at one end of the inner pipe, and the outer pipe extends to the other end of the inner pipe.

23. A flue pipe as claimed in any of Claims 20 to 22 in which the outer pipe stops just short of the inner pipe.

24. A flue pipe as claimed in any of Claims 15 to 23 in which the expansion accommodating member extends substantially the length of the outer pipe.

25. Aflue pipe as claimed in any preceding claim in which the flue pipe is of circular cross-section.

26. Aflue pipe as claimed in any preceding claim in which the inner pipe is provided in two longitudinal portions adapted to be joined together.

27. A flue pipe as claimed in any preceding claims in which the flue pipe is provided in two longitudinal portions adapted to be joined together.

28. Aflue pipe as claimed in any preceding claim in which the inner pipe is of fire clay material.

29. Aflue pipe as claimed in any preceding claim in which the outer pipe is of fire clay material.

30. A flue pipe as claimed in any of Claims 1 to 28 in which the outer pipe is of asbestos material.

31. Aflue pipe as claimed in any of Claims 1 to 28 in which the outer pipe is of stainless steel material.

32. A flue pipe as claimed in any preceding claim in which the flue pipe is adapted to extend through the coping member of a chimney stack, the expansion accommodating member or the outer pipe being adapted to engage an opening in the coping member.

33. A flue pipe as claimed in any of Claims 2 to 32 in which a top pipe extends from the top end of the outer pipe.

34. Aflue pipe as claimed in Claim 33 in which the free end of the top pipe extends beyond the outer pipe and the extending portion of the top pipe being of a reduced cross-sectional area.

35. A flue pipe as claimed in Claim 33 in which the inner cross-sectional area of the extending portion of the top pipe is iess than the inner cross-sectional area of the inner pipe.

36. A flue pipe as claimed in any of Claims 33 to 35 in which the lower end of the top pipe is inwardly relieved so that the outer peripheral lower edge of the top pipe acts as a drip means to cause water to drip from the outer surface of the top pipe.

37. Flue pipes substantially as described herein with reference to and as illustrated in the accompanying drawing.

38. An expansion accommodating member for use with any of the flue pipe as claimed in any of Claims 1 to 37.

39. A chimney stack incorporating a flue pipe in any of Claims 1 to 33.