Flexible Chimney Liner

Abstract

A flexible chimney liner is presented having a corrugation profile with an sheet strip width of about 110 mm to about 120 mm, preferably about 114 mm and a pitch of about 45 mm to about 55 mm, preferably about 50 mm.

Description

FIELD OF THE INVENTION

This invention relates generally to chimney components and in particular, to a flexible chimney liner.

BACKGROUND OF THE INVENTION

A chimney has a channel running its length for conveying exhaust gases from a fireplace, furnace or boiler acting as a heating source. Combustion products in the form of hot exhaust gases rise up the channel to the outside. They are typically vented vertically to ensure that the hot gases flow smoothly upward. The venting medium passes through the structure's roof to vent to the outside.

Over time it is not uncommon for the chimney venting medium to lose its sealing integrity, thereby allowing exhaust gasses to enter the living space. Rather than raising and rebuilding the chimney it is often advantageous to create a new venting medium by inserting a flexible chimney liner to reestablish sealing integrity.

Chimney liners are typically produced in lengths from 15 feet to 100 feet. Due to their length they are coiled for shipping. Uncoiling the chimney liner at the job site often presents problems because it is very difficult to uncoil the liner. Uncoiling the liner is time consuming and the uncoiled liner retains some memory and does not become completely straight.

Illustrated in FIG. 1, when the chimney liner is inserted into the existing chimney channel which may contain one or more offsets, it often requires “fishing” the liner through the channel. This requires that the liner be capable of flexing to pass an offset without becoming permanently distorted.

Additionally, the chimney liner must be able to coil for shipping without kinking The greater the flexibility the liner can achieve without distortion the wider the range of retrofits with which it can be used.

Accordingly, there is still a continuing need for improved flexible chimney liner designs. The present invention fulfills this need and further provides related advantages.

BRIEF SUMMARY OF THE INVENTION

Described below is a novel chimney liner design that retains significantly less coiling memory than existing liners so that it uncoils much easier and once uncoiled remains straight. The novel design also provides greater flexibility without permanent distortion than known designs.

Additionally, its novel profile provides greater crush resistance than known chimney liners.

In a preferred form the chimney liner has a corrugation profile with an sheet strip width W of about 110 mm to about 120 mm, preferably about 114 mm and a pitch P of about 45 mm to about 55 mm, preferably about 50 mm.

Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a further understanding of the present invention. These drawings are incorporated in and constitute a part of this specification, illustrate one or more embodiments of the present invention, and together with the description, serve to explain the principles of the present invention.

FIG. 1 is a side cutaway view of an installed flexible chimney liner.

FIG. 2 illustrates a section of flexible chimney liner during fabrication from a corrugated metal sheet.

FIG. 3 is a side view of a section of flexible chimney liner.

FIG. 4 is a side view of the lock seam of FIG. 2

FIG. PA-1 is side view of a known corrugation profile

FIG. 5 is a side view of the corrugation profile Z of FIG. 2.

Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.

DETAILED DESCRIPTION OF THE INVENTION

As required, detailed embodiments of the present invention are disclosed; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various forms. The figures are not necessary to scale, and some features may be exaggerated to show details of particular components. Therefore, specific structural and functional details disclosed are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention. Where possible, like reference numerals have been used to refer to like parts in the several alternative embodiments of the present invention described herein.

A flexible chimney liner 2 is fabricated using known technology, for example, by twisting a corrugated sheet 4, for example, a metal sheet, around a tool (not shown). FIG. 2 illustrates a section of the chimney liner 2 during fabrication from a corrugated metal sheet 4.

The flexible chimney liner 2 includes a wall 20 formed from the corrugated metal sheet 4. The metal sheet 4 has opposing first and second edges extending longitudinally along the metal sheet 4. The wall 20 includes a seam, such as lock seam 6, formed by abutting portions of the first and second edges. The lock seam 6 extends helically about and along a length of the wall 20. The metal sheet 4 has an interior wall side and an opposing exterior wall side. The interior wall side defines an inner wall surface 22 of the chimney liner 2, and the exterior wall side defines an outer wall surface 24 of the chimney liner 2. The metal sheet 4 has a sinusoidal profile defining the corrugation peaks 26 and corrugation valleys 28 of the chimney liner 2 (FIG. 3).

The novel profile of the corrugations (described in detail below) is not limited by the metal sheet material or the finished liner inside diameter DN (FIG. 3).

In its preferred form, the corrugated metal sheet 4 is aluminum or stainless steel having a width of about 110 mm to about 120 mm, preferably about 114 mm. After fabrication the flexible chimney liner 2 preferably has a finished inside diameter DN of about 127 mm to about 305 mm.

FIG. 3 is a side view of the fabricated flexible chimney liner 2. Lock seams 6 are formed during the manufacturing process from a sheet first edge and a sheet second edge in known fashion, for example, as illustrated in FIG. 4. The distance from lock seam to lock seam is referred to as the pitch P.

To aid in understanding the novelty of the claimed profile, comparison will be made to a known flexible chimney liner, illustrated in FIG. PA-1. The height H of a known chimney liner corrugation is 3.2 mm (0.126″). The angle α of the corrugations, determined by facing corrugation walls 8, 8′, is 53.8 degrees. The width of the corrugation CW, is 3.099 mm (0.122″), and the radius R of the corrugation is 1.346 mm (0.053″). The pitch P is 73 mm (2.874″).

In manufacturing a chimney liner, for a given sheet strip width W, the pitch P is determined by the corrugation height H; corrugation width CW; angle of the corrugations α; or a combination of each. Therefore, if a pitch P change is desired for a given sheet width W, the corrugation height H; and/or the corrugation width CW; and/or the angle of the corrugations α; or some combination of those parameters would need to be modified.

The relationship of the sheet strip profile parameters (radius R, width W, angle of the corrugations α, and height H) directly impact the pitch P. There is a maximum height H of any profile beyond which the manufacturing tooling becomes too weak to form the sheet strip properly without breaking. However, reducing the height H will make the liner less flexible.

There is also an optimal angle of the corrugations α. As the angle α is reduced the strip formation becomes more difficult while if the angle α is increased too much the liner is more likely to kink when coiled.

Likewise the radius R has a direct impact on the manufacturing process. The radius R has a value beyond which it cannot be decreased without making the tooling too weak to form the profile without breaking.

Unexpectedly, with a sheet strip width W of about 110 mm to about 120 mm, preferably about 114 mm, a pitch P of about 45 mm to about 55 mm was found to provide optimal manufacturing and finished chimney liner characteristics.

FIG. 5 is an enlarged cross sectional view of a portion Z (FIG. 3) of a length of the novel flexible chimney liner 2 constructed in accordance with an aspect of the present invention.

In developing the novel profile described below it was unexpectedly found that as the angle of the corrugations α approaches 0 degrees (parallel) the more favorable the chimney liner flexibility characteristics become. Significant improvement over known corrugation geometry was found when the angle of the corrugations α was less than or equal to about 10 degrees. About a 6 degree angle of corrugations α achieved superior characteristics.

When corrugation height H is smaller the chimney liner flexibility is reduced and when it is greater the chimney liner becomes weaker. Optimal corrugation height H providing the best balance of flexibility to strength was found to be from about 4.648 mm (0.183″) to about 4.826 mm (0.190″) with about 4.65 mm being preferred.

As the pitch P increases the ability to manufacture operatively acceptable smaller diameter liners is reduced As the pitch P decreases the liner becomes less flexible. Optimal pitch P providing the best balance of flexibility and the ability to run smaller diameters DN is about 45 mm to about 55 mm and most preferably about 50 mm (1.97″).

The optimal corrugation radius R is about 1.27 mm to about 1.52 mm and most preferably about 1.397 mm (0.55″). Preferably the lock seam 6 is about 2.5 mm wide.

As noted above, optimal chimney liner characteristics can be obtained with a sheet strip width W of about 110 mm to about 120 mm, preferably about 114 mm and a pitch P of about 45 mm to about 55 mm, preferably about 50 mm. Additional manufacturing benefit is obtained with also having an angle of corrugation a less than or equal to about 10 degrees, preferably about 6 degrees, a corrugation height H from about 4.648 mm to about 4.826 mm, preferably about 4.65 mm, a corrugation width CW of about 5.8 mm, and a corrugation radius R of about 1.27 mm to about 1.52 mm, preferably about 1.397 mm (0.55″) .

Using the novel profile parameter discussed above significantly and unexpectedly strengthens the chimney liner. Tests have shown the novel profile will hold 400 pounds per square foot as compared to 150 pounds per square foot with known profile parameters. The novel profile also produces a significant increase in flexibility, achieving a significantly greater degree of flex without kinking than that of known profiles. Once corrugations are kinked the chimney liner is ruined.

Although the present invention has been described in connection with specific examples and embodiments, those skilled in the art will recognize that the present invention is capable of other variations and modifications within its scope. These examples and embodiments are intended as typical of, rather than in any way limiting on, the scope of the present invention as presented in the appended claims.

Claims

1. A chimney liner having a profile comprising a sheet strip width of about 110 mm to about 120 mm and a pitch of about 45 mm to about 55 mm.

2. The chimney liner of claim 1 further comprising a corrugation height of about 4.648 mm to about 4.826 mm and an angle of corrugation less than or equal to about 10 degrees.

3. The chimney liner of claim 1 wherein the sheet strip width is about 114 mm and the pitch is about 50 mm.

4. The chimney liner of claim 2 wherein the corrugation height is about 4.65 mm and the angle of corrugation is about 6 degrees.

5. The chimney liner of claim 3 wherein the corrugation height is about 4.65 mm and the angle of corrugation is about 6 degrees.

6. The chimney liner of claim 1 further comprising a corrugation width of about 5.8 mm.

7. The chimney liner of claim 1 further comprising a corrugation radius of about 1.27 mm to about 1.52 mm.

8. The chimney liner of claim 1 further comprising an inside diameter of about 127 mm to about 305 mm.

9. A chimney liner having a profile comprising a sheet strip width of about 110 mm to about 120 mm, a pitch of about 45 mm to about 55 mm, an angle of corrugation less than or equal to about 10 degrees, a corrugation height from about 4.648 mm to about 4.826 mm, a corrugation width of about 5.8 mm, and a corrugation radius of about 1.27 mm to about 1.52 mm.

10. The chimney liner of claim 9 wherein the sheet strip width is about 114 mm and the pitch is about 50 mm.

11. The chimney liner of claim 9 wherein the corrugation height is about 4.65 mm and the angle of corrugation is about 6 degrees.

12. The chimney liner of claim 10 wherein the corrugation height is about 4.65 mm and the angle of corrugation is about 6 degrees.13. The chimney liner of claim 10 further comprising a corrugation width of about 5.8 mm.

13. The chimney liner of claim 9 further comprising an inside diameter of about 127 mm to about 305 mm.

14. A chimney liner manufacturing process comprising the steps of:

forming corrugations in a sheet strip;

twisting and seaming the sheet strip to form a chimney liner;

wherein the corrugations form a chimney liner profile comprising a sheet strip width of about 110 mm to about 120 mm and a pitch of about 45 mm to about 55 mm.

15. The process of claim 14 wherein the sheet strip width is about 114 mm and the pitch is about 50 mm.

16. The process of claim 14 wherein the chimney liner profile further comprises a corrugation height of about 4.648 mm to about 4.826 mm and an angle of corrugation less than or equal to about 10 degrees.

17. The process of claim 15 wherein the chimney liner profile further comprises a corrugation height of about 4.648 mm to about 4.826 mm and an angle of corrugation less than or equal to about 10 degrees.

18. The process of claim 15 wherein the chimney liner profile further comprises an inside diameter of about 127 mm to about 305 mm.

19. The process of claim 14 wherein the chimney liner profile further comprises an inside diameter of about 127 mm to about 305 mm.

20. The process of claim 14 wherein the chimney liner profile further comprises an angle of corrugation less than or equal to about 10 degrees, a corrugation height from about 4.648 mm to about 4.826 mm, a corrugation width of about 5.8 mm, and a corrugation radius of about 1.27 mm to about 1.52 mm.