Abstract:
A joining connection for the ends of flue gas conduits, each of which is provided with a complemental taper joint, each taper joint having equally-spaced locking tabs extending outwardly therefrom, the locking tabs of each conduit being so positioned as to be substantially axially aligned and in close adjacency when the taper joints of the conduits are joined, and a split clamping band or locking ring sleeved on the taper joints and having an integral screw tightening mechanism and a series of equally-spaced slots therein, with the locking tabs of each conduit being captured in the slots of the clamping band, whereby tightening of the screw mechanism brings the clamping band into tight engagement with the conduits for securely locking the conduits together.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to connectors for joining together the ends of flue gas conduits of the type used for venting smoke and flue gases to the atmosphere. 
     2. Description of Related Art 
     U.S. Pat. No. 4,874,191 discloses a connection which utilizes a clamping ring and a fastening mechanism for joining together the tapered ends of flue gas conduits. 
     While this joining connection is satisfactory, it fails to provide air space clearance at the connection between the conduits, makes no provision for indexing of the tab fasteners, has no means for tightening the clamping ring, and does not permit assembly of the conduits without the necessity of rotating the components. 
     There is a need for a more rigorous vent system which utilizes a joining connection differing substantially from those presently available in the prior art. 
     SUMMARY OF THE INVENTION 
     The joining connection of the invention employs a tapered joint geometry at the flue gas conduit ends; but, rather than the fastening mechanism of the prior art, a substantially more rigorous mechanical locking system is utilized which comprises shaped, strategically located, locking tabs which provide a means for securing together the conduit ends, and a clamping band or locking ring having slots for capturing the locking tabs and a screw mechanism for tightening the band from a single location, thereby affording fast installation for locking the conduits together. 
     In one of its embodiments the conduits of the flue gas joining connection of the invention employ a double-wall construction of spaced, concentric, inner and outer walls. 
     This double-wall construction allows for an insulating blanket of air (or other tangible materials such as fiberglass, mineral wool, etc.) between the inner wall and the outer wall. This air insulation has the advantage of keeping the flue gases warmer, as well as making the skin temperature of the outer wall cooler than would be possible with an uninsulated single-wall section. The reduced skin temperature allows the joining connection of the invention to be installed in closer proximity to combustible materials. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded, fragmentary, front perspective view of a flue gas conduit joining connection before assembly of a pair of conduits, embodying a first form of the invention. 
     FIG. 2 is a front perspective view of the flue gas conduit joining connection of FIG. 1 following assembly of the conduits and prior to installation of a clamping band or locking ring; 
     FIG. 3 is a front perspective view similar to FIG. 2 following installation of a clamping band or locking ring; 
     FIG. 4 is a front elevational view of one of the flue gas conduits of FIG. 1; 
     FIG. 5 is a top plan view of the flue gas conduit of FIG. 4; 
     FIG. 6 is a somewhat schematic, fragmentary, part sectional view of the female end of one of the conduits of FIG. 1; 
     FIG. 7 is a somewhat schematic, fragmentary, part sectional view of the male end of one of the conduits of FIG. 1; 
     FIG. 8 is a somewhat schematic, fragmentary, part sectional view of the male and female ends of the conduits of FIGS. 6 and 7 following interengagement; 
     FIG. 9 is a somewhat schematic, fragmentary, part sectional view similar to FIG. 8 following installation of a clamping band or locking ring; 
     FIG. 10 is an exploded, fragmentary, front perspective view of a flue gas conduit joining connection before assembly of a pair of conduits, embodying a second form of the invention; 
     FIG. 11 is a front perspective view of the flue gas conduit joining connection of FIG. 10 following assembly of the conduits and prior to installation of a clamping band or locking ring; 
     FIG. 12 is a front perspective view similar to FIG. 11 following installation of a clamping band or a locking ring; 
     FIG. 13 is a somewhat schematic, fragmentary, cross sectional view of the female end of one of the conduits of FIG. 10; 
     FIG. 14 is a somewhat schematic, fragmentary, cross sectional view of the male end of one of the conduits of FIG. 10; 
     FIG. 15 is a somewhat schematic, fragmentary, cross sectional view of the male and female ends of the conduits of FIGS. 13 and 14 following interengagement; and 
     FIG. 16 is a somewhat schematic, fragmentary, cross sectional view similar to FIG. 15 following installation of a clamping band or locking ring. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring first to FIGS. 1-9, a flue gas conduit joining connection, generally indicated by  10 , embodying a first form of the invention, is provided for joining the end of a first cylindrical flue gas conduit, generally indicated by  12 , to the end of a second cylindrical flue gas conduit generally indicated by  14 . 
     Conduits  12  and  14  are identical, with conduit  12  being shown in FIGS. 4 and 5 for illustrative purposes. 
     Each conduit  12  and  14  has a double-wall construction which includes an inner pipe  16  and an outer shield  18  spaced from and concentric therewith. 
     This double-wall construction provides a space  19  for an insulating blanket of air or other tangible material such as fiberglass, mineral wool, not shown, between inner wall  16  and outer shield  18 . This insulation has the advantage of keeping the flue gases warmer, as well as making the skin temperature of outer shield  18  cooler than would be possible with an uninsulated single-wall section. This reduced skin temperature allows the forming connection of the invention to be installed in closer proximity to combustible materials. 
     Inner pipe  16  has a female component, generally indicated by  20 , formed integrally on one of its ends and a male component, generally indicated by  22 , formed integrally on its opposite end. 
     Female component  20  of inner pipe  16  of first conduit  12 , and male component  22  of inner pipe  16  of second conduit  14  are adapted to be brought into mating, telescopic relationship and clamped together by an annular clamping band or locking ring generally indicated by  24 . 
     Clamping band or locking ring  24  is split centrally of its length to provide adjacent offset ends  26  and  28  each of which has a central opening therein, not shown, through which a bolt  30  extends, the bolt having a nut  32  threaded thereon. 
     Clamping band  24  or locking ring is provided with a plurality of equi-spaced, longitudinally-extending slots  34  along its longitudinal axis, all for purposes to appear. 
     The direction of flue gas flow in the conduits is indicated by the arrow “a” in FIGS. 1-9 of the drawings. 
     Female component  20  of inner pipe  16  of each conduit  12  and  14 , includes a bell-shaped, annular end joint  36  which tapers inwardly from an outer end face  38  and terminates at an inner shoulder  40  which merges with the body of inner pipe  16 . 
     Male component  22  of inner pipe  16  of each conduit  12  and  14  includes a reverse, bell-shaped, annular end joint  42  which tapers outwardly from an outer end face  44  and terminates at an inner shoulder  46  which merges with the body of inner pipe  16 . 
     A first set of locking members, generally indicated by  48 , is fixed to the outer periphery of end joint  36  of female component  20  at equally-spaced intervals around the circumference of the end joint and are located at or adjacent the outer end of end joint  36 , for purposes to appear. 
     A second set of locking members, generally indicated by  50 , is fixed to the outer periphery of inner pipe  16 , and are located immediately above shoulder  46  and adjacent end joint  42  of male component  22  at equally-spaced intervals around the circumference inner pipe  16 , also for purposes to appear. 
     The spacing between the locking members of each set of locking members  48  and  50  corresponds to the spacing between slots  34  of clamping band or locking ring  24 , also for purposes to appear. 
     As best seen in FIGS. 6 and 7, the locking members of each set  48  and  50  are identical and are somewhat U-shaped in side elevation. 
     Each locking member includes a flat, rectangular, upright wall  52  which has an integral locking tab  54  extending angularly outwardly from one of its ends and an integral base wall  56  which extends horizontally outwardly from its opposite end. 
     The outer ends of locking tabs  54  are preferably rounded as at  55 , thereby providing a smooth surface less apt to injure an installer handling the conduits and for other purposes, as will appear. 
     However, while a rounded end on locking tabs  54  is preferred, the ends may have any other shape, such as square, rectangular, triangular, etc. 
     Base wall  56  has an integral upright finger  58  extending outwardly from its opposite outer end in the direction of locking tab  54  and disposed in spaced, substantial parallelism to upright wall  52 . 
     Upright wall  52  of each locking member of first set  48  is fixed to the outer periphery of end joint  36  of female component  20  of inner pipe  16  as by spot welds, not shown, while each finger  58  is similarly fixed to the inner periphery of outer shield  18  as by a spot weld, not shown. 
     Upright wall  52  of each locking member of second set  50  is fixed to the outer periphery of inner pipe  16  immediately adjacent end joint  42  of male component  22  as by spot welds, not shown, while each finger  58  is similarly fixed to the inner periphery of outer shield  19  as by a spot weld, not shown. 
     In addition to their other functions, the locking members of each set  48  and  50  serve to hold outer shield  18  in spaced concentricity to inner pipe  16 , as will appear. 
     As shown in the drawings, upright wall  52 , base wall  56  and upright finger  58  of the locking members or each set  48  and  50  provide about one inch of separation between inner pipe  16  and outer shield  18 . However, greater or lesser separation distances between the components may be provided, as desired. 
     Reverse bell-shaped end joint  42  of male component  22  is of appropriate size and configuration as to be telescopically receivable in bell-shaped end joint  36  of female component  20  when the ends of the two components are interengaged. 
     When component  20  of first flue gas conduit  12  and component  22  of second flue gas conduit  14  are interengaged, the position of locking tabs  54  of the first set of locking members  48  on female component  20 , and the position of locking tabs  54  on the second set of locking members  50  on male component  22 , is such that the locking tabs of each set  48  and  50  are aligned and are disposed in close adjacency, as shown in FIGS.  2 , 3 , 8  and  9 . 
     It will be recalled that locking tabs  54  of first set  48  are located at or adjacent outer end face  38  of end joint  36  of female component  20 , while locking tabs  54  of second set  50  are located immediately above shoulder  46  and adjacent end joint  42  of male component  22 . 
     This placement of locking tabs  54  of first and second sets  48  and  50 , respectively, is important, since such placement is related to the amount of overlap which occurs when component  22  is assembled into female component  20 , assuring that the locking tabs of each set are disposed in close adjacency when the components  20  and  22  are interengaged. 
     At this time, clamping band or locking ring  24  is assembled onto components  20  and  22  as shown in FIGS. 3 and 9, with locking tabs  54  of both components extending through and being captured in slots  34  of band  24 , with the slots being of sufficient length as to easily accommodate the locking tabs. 
     Rounded ends  55  of locking tabs  54  facilitate entry of the locking tabs into slots  34  of band  24  while insuring against injury to the installer. 
     Bolt  30  is now tightened relative to nut  32 , drawing offset ends  26  and  28  of clamping band or locking ring  24  closer together to bring the clamping band into tight engagement with components  20  and  22  to securely lock first conduit  12  and second conduit  14  together. 
     Clamping band or locking ring  24  provides a mechanical connection between the two assembled conduits. It also serves to pull together the conduits, making a pressure-tight assembly. Locking ring  24  may be tightened from a single location using a hand tool. This single-point fastening system is an improvement over previous structures as it allows one installer to complete an assembly without rotating the conduits, or repositioning himself relative to the conduits. 
     Referring now to FIGS. 10-16, a flue gas joining connection, generally indicated by  110 , embodying a second form of the invention, is provided for joining the end of a first cylindrical flue gas conduit, generally indicated by  112 , to the end of a second cylindrical flue gas conduit, generally indicated by  114 . 
     In the embodiment of FIGS. 10-16, flue gas conduits  112  and  114  have no outer shields; otherwise, conduits  112  and  114  and joining connection  110  are identical to conduits  12  and  14  and joining connection  10  of the embodiment of FIGS. 1-9. 
     Each conduit  112  and  114  includes a main body portion  116  which has a female component, generally indicated by  120 , formed integrally on one of its ends and a male component, generally indicated by  122 , formed integrally on its opposite end. 
     Female component  120  of first conduit  112 , and male component  122  of second conduit  114  are adapted to be brought into mating, telescopic relationship and clamped together by annular clamping band or locking ring  24  of FIGS. 1-9. 
     The direction of flue gas flow in conduits  112  and  114  is indicated by the arrow “a′”in FIGS. 10-16 of the drawings. 
     Female component  120  of both conduits  112  and  114  includes a bell-shaped, annular end joint  136  which tapers inwardly from an outer end face  138  and terminates at an inner shoulder  140  which merges with main body portion  116  of each conduit. 
     Male component  122  of each conduit  112  and  114  includes a reverse, bell-shaped, annular end joint  142  which tapers outwardly from an outer end face  144  and terminates at an inner shoulder  146  which merges with main body portion  116  of each conduit. 
     In the embodiment of FIGS. 10-12, a first set of locking members, generally indicated by  148 , is fixed to the outer periphery of end joint  136  of female component  120  of each conduit  112  and  114  at equally-spaced intervals around the circumference of end joint  136 , and are located at or adjacent the outer end of end joint  136 , for purposes to appear. 
     A second set of locking members, generally indicated by  150 , is fixed to the outer periphery of main body portion  116 , and are located immediately adjacent end joint  142  of male component  122  of each conduit  112  and  114  at equally-spaced intervals around the circumference of end joint  142 , also for purposes to appear. 
     The spacing between the locking members of each set of locking members  148  and  150  corresponds to the spacing between slots  34  of clamping band or locking ring  24 , for purposes to appear. 
     The locking members of each set  148  and  150  are identical to the locking members of each set  48  and  50  of the embodiment of FIGS. 1-9. 
     The locking members of each set  148  and  150  are somewhat U-shaped in side elevation and include a flat, rectangular, upright wall  152  which has an integral locking tab  154  extending angularly outwardly from one of its ends and an integral base wall  156  extending horizontally outwardly from its opposite end. Locking tab  154  preferably has a rounded outer end  155  for purposes as discussed with regard to locking tab  54 . 
     Base wall  156  has an integral upright finger  158  extending outwardly from its opposite outer end and disposed in spaced, substantial parallelism to upright wall  152 . 
     Upright wall  152  of each locking member of first set  148  is fixed to the outer periphery of end joint  136  of female component  120  of each conduit  112  and  114  as by spot welds, not shown. 
     Upright wall  152  of the locking members of second set  150  is fixed to the outer periphery of main body portion  116  immediately adjacent end joint  142  of male component  122  of each conduit  112  and  114  as by spot welds, not shown. 
     Referring to FIGS. 13-16, since an outer shield is not employed with conduits  112  and  114 , a more simplified locking means may be utilized. 
     In FIGS. 13-16, a first set of locking members, generally indicated by  248 , is fixed to the outer periphery of end joint  136  of female component  120  of first conduit  112 . 
     A second set of locking members, generally indicated by  250 , is fixed to the outer periphery of main body portion  116  immediately adjacent end joint  142  of male component  122 . 
     The locking members of each set  248  and  250  are somewhat L-shaped in side elevation and include a flat, rectangular, upright wall  252  which has an integral locking tab  254  extending angularly outwardly from one end. Locking tab  254  preferably has a rounded outer end  255  for purposes as discussed with regard to locking tab  54 . 
     Upright wall  252  of the locking member of first set  248  is fixed to the outer periphery of end joint  136  of female component  120  of first conduit  112  as by spot welds, not shown. 
     Upright wall  252  of the locking members of second set  250  is fixed to the outer periphery of main body portion  116  immediately adjacent end joint  142  of male component  122  of second conduit  114  as by spot welds, not shown. 
     Reverse bell-shaped end joint  142  of male component  122  of second conduit  114  is of appropriate size and configuration as to be telescopically receivable in bell-shaped end joint  136  of female component  120  of first conduit  112  when the ends of the two components are interengaged. 
     In the embodiment of FIGS. 10-16, as with the embodiment of FIGS. 1-9, when components  120  and  122  of conduits  112  and  114  are interengaged, locking tabs  154  or  254  of the first set of locking members  148  or  248  of female component  120  are substantially aligned with and are disposed in close adjacency to locking tabs  154  or  254  of the second set of locking members  150  or  250  of male component  122 . 
     At this time, and as shown in FIG. 16, clamping band or locking ring  24  is assembled onto components  120  and  122 , with locking tabs  154  or  254  of both components extending through and being captured in slots  34  of band  24 , with the slots being of sufficient length to easily accommodate the locking tabs. 
     Bolt  30  is now tightened relative to nut  32  to draw offset ends  26  and  28  of clamping band or locking ring  24  closer together, bringing the band into tight engagement with components  120  and  122  to securely lock conduits  112  and  114  together.