Expansion and length adjustment joint

An expansion and length adjustment joint for use with a double walled metal chimney, the chimney having an inner flue wall and an outer casing wall, the adjustment joint having an inner sliding sleeve with a flange at one end thereof. An upper flue wall connecting band is sealingly disposed around the inner sliding sleeve flange and a flange of the inner flue wall. A gasket retaining collar is secured against the inner sliding sleeve, thus retaining a flue gas seal therealong with thermal expansion.

BACKGROUND OF THE INVENTION 
1. Field of the Invention. 
The present invention relates to a double walled metal chimney having an 
inner flue wall and outer casing wall, and more particularly but not by 
way of limitation, to an expansion and length adjustment joint for joining 
chimney sections. 
2. Brief Description of the Prior Art. 
Heretofore, there have been a number of different types of double walled 
metal chimneys with expansion joints, such as the expansion joint 
described in U.S. Pat. No. 4,029,343 to Stone. This expansion joint, while 
appearing similar to the present invention, uses an annular gasket 
supported by, and in sealed engagement with, an inner wall end portion. 
This joint does not provide the advantages of having a separate gasket 
retaining collar as described herein. Also, U.S. Pat. No. 1,824,422 to 
Badger, U.S. Pat. No. 2,850,264 to Grable, U.S. Pat. No. 3,208,539 to 
Henderson, U.S. Pat. No. 3,427,051 to White et al., U.S. Pat. No. 
3,544,135 to Hoerrner, U.S. Pat. No. 3,583,730 to Kozlowski and U.S. Pat. 
No. 3,902,744 to Stone describe different types of metal chimneys, 
expansion joints and related metal equipment used in chimneys. None of 
these prior art patents describes the particularly unique features and 
advantages of the subject adjustment joint with gasket retaining collar. 
SUMMARY OF THE INVENTION 
The present invention provides an expansion and length adjustment joint 
with a separate sliding gasket retaining collar used for holding a 
graphited or graphite coated gasket to prevent the escape of flue gas from 
inner flue walls. The joint includes an inner sliding sleeve which engages 
the gasket and inner circumference of a lower flue wall to provide for the 
linear thermal expansion of the chimney while providing a positive seal. 
The expansion and length adjustment joint eliminates the need during a 
chimney installation of cutting individual casing and flue walls. Also the 
subject joint allows for expansion and length adjustment during the 
expansion of the flue walls. 
The invention is rugged in construction, provides a minimum of parts 
required for an expansion joint and can be easily installed during the 
installation of chimney sections. 
The expansion and length adjustment joint includes a cylindrical inner 
sliding sleeve having an outwardly extending flange adapted for engagement 
with a flange extending outwardly from a cylindrical upper flue wall. The 
flanges are secured together using an upper flue connecting band. The 
joint further includes a cylindrical gasket retaining collar having an 
outwardly extending flange used for engagement with an outwardly extending 
flange of a cylindrical lower flue wall. The flanges are secured together 
using a lower flue connecting band. The gasket retaining collar further 
includes an annular groove therearound for receiving a graphited gasket or 
the like therein. By tightening a gasket compression band the gasket is 
rigidly secured inside the annular groove and against the outer 
circumference of the sliding sleeve. 
The advantages and objects of the present invention will become evident 
from the following detailed description of the drawings when read in 
connection with the accompanying drawings which illustrate preferred 
embodiments of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS 
In FIG. 1 an expansion and length adjustment joint is designated by general 
reference numeral 10. The joint 10 is used for installation between an 
upper chimney section 12 and a lower chimney section 14. The upper chimney 
section 12 includes an outer casing wall 16 and an inner flue wall 18. The 
lower section 14 includes an outer casing wall 20 and an inner flue wall 
22. A longitudinally split cylindrical outer casing jacket 24 is disposed 
about the outer casing walls 16 and 20 as shown. The casing jacket 24 
comprises two identical halves, designated 24A and 24B secured together 
via flanges 26 and 28 disposed on opposite sides of the casing jacket 24 
along the longitudinal seam thereof and secured together by bolts 29. (One 
side of the casing jacket 24 and thus one pair of the flanges 26, 28 are 
shown in FIG. 1 which is sufficient for the identical details of the 
opposing side thereof.) 
The expansion and length adjustment joint 10 includes a cylindrical inner 
sliding sleeve 30 which has an outwardly extending radial flange 32 used 
for engagement against an outwardly extending radial flange 34 at the 
lower end of the upper flue wall 18. The two radial flanges 32 and 34 are 
joined together in a tight seal by a circular upper flue wall connecting 
band 36. The band 36 has a bracket 35 at each of its ends that meet and 
are secured together via fasteners 37 for tightening the band 36 around 
the radial flanges 32 and 34. 
The inner sliding sleeve 30 extends downwardly and is received past the 
upper end of the lower flue wall 22 and adjacent the inner circumference 
of the wall 22. The joint 10 further includes a cylindrical gasket 
retaining collar 40 which is received around the sliding sleeve 30 and 
which includes a slotted retaining groove 42 therearound for receiving and 
retaining a gasket 44. A review of FIG. 1 and FIG. 1A will show that the 
retaining groove 42 has an angular cross section. The gasket 44 can be a 
graphited ceramic fiber braid or similar type of gasket, and is compressed 
against the outer circumference of the sleeve 30 by a compression band 46 
which is received in the bottom of the groove 42. The band 46 is tightened 
via radial brackets 50 which extend outwardly therefrom through a slot in 
the groove 42, and a fastener 52 secures the radial brackets 50 together. 
Accordingly, when the sliding sleeve 30 slides lengthwise due to the 
longitudinal expansion of the chimney sections 12 and 14, flue gas is 
prevented from escaping from between the outer circumference of the sleeve 
30 and the inner circumference of the lower flue wall 22. 
In FIG. 1A an enlarged view of the gasket retaining collar 40 is shown with 
the gasket 44 held in compression against the side of the outer 
circumference of the sleeve 30 and against the sides of the groove 42. 
Also shown in this figure is the collar 40 with an outwardly extending 
radial flange 54 therearound used for engagement against the side of an 
outwardly extending radial flange 56 at the end of the lower flue wall 22. 
The two radial flanges 54 and 56 are joined together using a lower flue 
wall connecting band 58. The band 58 has outwardly extending brackets 60 
and metal fasteners 62 for securing the ends of the band 58 together to 
compress the band around the radial flanges 54 and 56 to provide a tight 
seal. 
Referring back to the joint 10 shown in FIG. 1, the outer casing jacket 24 
extends downwardly from the upper casing wall 16 towards the lower casing 
wall 20. A groove 64 is provided in a collar 65 and fits around a circular 
bead 66 in the casing wall 16 for an improved lock around the lower end of 
the wall 16. The inner circumference of the casing jacket 24 at its lower 
end is received around a similar circular bead 68 disposed around the end 
of the lower casing wall 20. A groove 70 is formed at the top end of the 
casing jacket, as shown, the groove 70 being dimensioned to accommodate 
the thickness of the collar 65 and that of the bead 68 (in the top end 
portion of the lower casing wall 20) so as to permit jacket casing 24 to 
remain cylindrically true as the flanges 26, 28 are secured via the bolts 
29. As partially shown in FIG. 1, a tongue member 72 is attached along the 
underside of the flange 28 and is disposed to extend beneath the flange 26 
to provide a metal facing seal beneath the longitudinal seam of the casing 
jacket 24. 
Also shown in FIG. 1 is the sliding sleeve 30 with its lower end extending 
past the upper end of the lower flue wall 22 to provide for expansion and 
an improved seal to prevent flue gas from escaping from between the inner 
flue wall 22 and the sliding sleeve 30. 
Finally, the upper and lower chimney sections 12 and 14 are interconnected 
by connectors that connect the inner flue wall 18, the inner flue wall 22, 
and the interdisposed inner sliding sleeve 30, to the outer casing walls 
16 and 20. These connectors are not shown, as such can be of conventional 
design, such as appropriately disposed strapping; but preferably, the 
connectors utilized for the expansion and length adjustment joint 10 will 
be the "J"-shaped expansion clips taught in U.S. Patent Application Ser. 
No. 945,355, filed on Dec. 22, 1986. Insofar as may be necessary, the 
disclosure of that patent application is incorporated herein by reference. 
It is clear that the present invention is well adapted to carry out the 
objects and to attain the ends and advantages mentioned herein as well as 
those inherent in the invention. While a preferred embodiment of the 
invention has been described for the purposes of this disclosure, numerous 
changes can be made which will readily suggest themselves to those skilled 
in the art and which are encompassed within the spirit and scope of the 
invention disclosed herein and as defined in the appended claims.