GB2082282A - Improvements in or Relating to Flange Type Duct Joints - Google Patents

Abstract

A joint assembly for connecting the ends of a pair of generally rectangular sheet metal ducts (10) includes a pair of frames secured to each other and connected to the respective duct ends. The frames include flange portions (28, 34), each flange portion having an upstanding channel shaped leg portion (36) and an angularly extending duct receiving leg portion (44). A corner piece (66) according to the invention connects adjacent flange portions and extends into channel potions (52) of the upstanding leg portions (36) to form a generally rectangular frame. The end portions (22, 24) of the ducts (10) are then inserted into longitudinal openings of the duct receiving leg portions (44). A flowing type gasket material (64) is positioned longitudinally in the flanges in a longitudinal pocket (62). The end of each duct wall partially displaces the gasket material (64) so that the gasket material extrudes outwardly around the upper and lower surfaces of the duct wall and between the ends of the flange portion and the corner piece (66). <IMAGE>

Description

1 GB 2 082 282 A 1-

SPECIFICATION

Corner Pieces for Connecting a Plurality of Adjacent Flange Portions of a Flange Type Duct Joint Assembly for Connecting the End 5 Portions of Generally Rectangular Ducts The invention relates to corner pieces for connecting a plurality of adjacent flange portions of a duct joint assembly for connecting the end portions of generally rectangular ducts.

United States Patent 3 712 650 discloses a flange connection for connecting the ends of rectangular air conditioning ducts that includes flange portions each having a horizontal leg portion secured to the end portion of the duct and a vertical channel shaped leg for receiving the arm of an angular corner piece. A wall of the horizontal flange portion has a sloping intermediate portion that permits visual access to the bend areas between the adjacent walls of the duct and ends of the duct walls.

The angular corner pieces have arm portions which each extend into an opening in the vertical channel sloped flange. The arm portions are so dimensioned vertically that the lower surface of each arm abuts the lower wall of the horizontal flange. With this arrangement the end of the duct wall abuts or rests against the surface of the corner piece arm extending into the channel shaped opening.

Another joint assembly for connecting the ends 95 of a pair of ducts is disclosed in German Application No. P.2556167 filed December 13, 1975, and includes a plulity of flange portions secured to the ends of the ducts and angular corner pieces positioned in vertically extending channel shaped openings in the respective flange portions to form a generally rectangular frame secured to the ends of the ducts. The flange portions each have a generally horizontal duct receiving leg and a vertical channel shaped leg. The duct receiving leg portion has a longitudinal opening for receiving the duct end wall and one wall of the vertically extending channel shaped leg has an inturned or inwardly rebent portion that forms a longitudinally extending lip spaced from 110 the lower wall of the horizontal duct receiving leg. The duct end portion is arranged to extend into the space between the longitudinally extending lip and the lower wall of the horizontal duct receiving leg. In position, the duct end wall abuts the inner surface of the outer vertical wall of the upstanding channel shaped leg. The arm of the corner piece is arranged to extend into the opening above the inturned lip so that the corner piece arm portion is spaced from the duct end wall by the inturned lip portion. The corner pieces have arms with a curved configuration so that pairs of facing arms in adjacnt frames are intended to exert a joinder pressure onthe respective frame when the corner pieces are bolted to each other.

In the above joint assemblies, the duct end walls abut either the arms of the corner pieces or abut the inner surface of the frame channel shaped leg portion outer vertical wall. Where the end of the duct wall rests against the arm of the corner section, a space is provided between a substantial portion of the outer vertical wall of the channel shaped leg and the end of the duct wall. Where the end of the duct wall is positioned in the space between the inturned lip and the horizontal bottom wall, the duct end wall abuts a portion of the vertical wall of the frame section between the lip and the horizontal bottom wall. In either instance, irregularities on the surface of the duct or on the surface of the frame portions permit leakage of air from the duct through the flange connection. Positioning gasket material on the outer surface of the frame portions does not eliminate this air leakage since the leakage is occurring within the frame portions and around the duct end wall.

In German Offenlegungschrift 2221312 published November 15, 1973 a fibrous gasket material is disclosed as positioned between the upper surface of the duct end portion and the under surface of the inturned rebent portion.

French Patent 1363255 discloses two pieces of sheet metal joined by a fold arrangement with a sealant engaged to the edge of one of the metal sheets. United States Patent 3246918 discloses a flange connection in which sealing is achieved by the penetration of an end of a duct into a mastic.

One problem encountered with the joint assemblies of the prior art is the inability to form an air-tight seal around the duct end wall positioned oppositely of the vertical wall of the frame section adjacent the horizontal bottom wall of the frame section.

One proposed solution to this problem, as disclosed in the German OLS. referred to above is positioning a longitudinally extending gasket in the longitudinal space between the inturned rebent portion and the lower wall of the horizontal duct receiving leg. If when the duct end wall is inserted in the duct receiving leg portion, the gasket material is rolled up against the inner surface of the vertical wall of the channel shaped leg portion, and incomplete seal is formed around the end of the duct and the inner surface of the bottom wall of the duct receiving leg portion. Consequently, the end of the duct is substantially spaced from the inner vertical wall of the channel shaped leg portion. An air space is thus formed between the outside gasket on the outer surface of the frame portions and the duct edge because the outside gasket rests on the corner pieces and does not contact the duct edge. This permits air from the duct to flow around the end of the duct and between the outside surface of the duct and the under surface of the corner piece. Thus, air leaks from the ducts at the corners of the frame connecting the ducts.

According to the present invention there is provided a corner piece for connecting a plurality of adjacent flange portions for a duct joint, the corner piece comprising a body portion and a pair of legs extending angularly therefrom, said body portion having a corner section with a flange -2 GB 2 082 282 A 2_ portion extending from said body portion, said flange portion having a first surface and a second surface, said first and second surfaces terminating in an edge portion, and said first and second surfaces of said flange portion being angularly displaced from said body portion.

The outer surface of the corner piece flange portion is preferably curved rearwardly away from the front wall inner surface. With this arrangement the duct end portion is permitted to extend beyond the corner piece flange portion so that the duct edge can penetrate an external gasket positioned on the surface of the flange portions and the corner pieces. This arrangement provides an effective corner seal for the duct joint assembly.

An embodiment of the invention will now be described, by way of illustrative and non-limiting example, with reference to the accompanying drawings, in which:- Figure 1 is a fragmentary, exploded perspective view of a flange type duct joint assembly for connecting the end portions of a pair of ducts, illustrating a plurality of angular corner pieces according to the present invention for connecting adjacent flange portions to form a frame for receiving the end portions of the ducts. Figure 2 is an enlarged perspective view of an angular corner piece and adjacent flange portions. 30 Figure 3 is a perspective view of a corner of the end of a duct with the flange portions connected thereto and the corner piece connecting the adjacent flange portions. Figure 4 is a fragmentary perspective view of a corner of the end portion of a duct sealingly connected to a pair of adjacent flanges connected by a corner piece, illustrating the edge of the duct extending above a flange portion of the corner piece. A deformable gasket material in the flanges is shown extruded from the end of one flange but is omitted from the end of the other flange for purposes of illustration only to more clearly show the relationship between the end of the flange, the flange of the corner piece, and the end of the duct.

Figure 5 is a perspective view of an angular corner piece, illustrating a downwardly curved flange portion extending from the inner corner of the corner piece.

Figure 6 is a perspective view of the opposite face of the angular corner piece shown in Figure 5, illustrating the configuration of the downwardly curved flange portion of the corner piece.

Figure 7 is a fragmentary perspective view of a corner piece, illustrating the downwardly curved flangeportion.

Figure 8 is a fragmentary sectional view of the end portion of the duct abutting the front wall of an upstanding channel shaped leg portion of the flange and penetrating the gasket member positioned on the flange and the corner piece, illustrating the flange portion of the corner piece curved rearwardly from the front wall of the channel shaped leg portion.

Figure 9 is a fragmentary sectional view of the130 end portions of a pair of ducts connected by a duct joint assembly embodying the present invention, illustrating the flanges secured to the ducts with the flanges abutting a gasket therebetween.

Figure 10 is a sectional view of a corner piece taken along the lines X-X of Figure 7, illustrating the configuration of a leg of the corner piece and the curved flange portion of the corner piece.

Figure 11 is a sectional view of a corner piece taken along lines X1-Xl of Figure 7, illustrating the configuration of a corner piece.

Referring to the drawings and particularly to Figures 1-4, there is illustrated the end portion of a pair of ducts generally designated by the numeral 10 in which each duct 10 has an upper duct wall 12, a lower duct wall 14, and a pair of vertical duct sidewalls 16 and 18. The ducts 10 are formed in the configuration illustrated in Figure 1 with the longitudinally extending sealed corner joint 20 between the lower duct wall 14 and the sidewall 16.

As illustrated in Figure 3, the duct upper wall 12 terminates in an end portion 22 and the duct sidewall 18 terminates in an end portion 24. It should be understood, although not shown, that the other duct walls 14 and 16 terminate in similar end portions so that the end portions of the duct 10 extend along a plane transverse to the longitudinal axis of the duct 10.

Each of the ducts 10 preferably is fabricated from galvanized sheet material and may have various thicknesses. For example, commercial grade 20 gauge duct has a thickness of between 0.906 and 1. 106 millimeters. The galvanized surface of the duct walls also provides a relatively irregular surface so that the thickness of the sheet metal forming the duct 10 is not uniform along the duct end portions.

The end portions of the pair of ducts 10 are secured to each other by a pair of frame members generally designated by the numeral 26. The frame members 26 are similar in construction and are secured to the ends of adjacent duct sections and are connected to each other by bolts 25 and nuts 27, shown in Figure 1 as will be described later in greater detail. Each frame 26 includes an upper flange portion 28, a lower portion 30 and a pair of side flange portions 32 and 34. The configuration of the flange portions 28-34 are identical and are preferably cut to a preselected length from an elongated sheet metal strip that has been roll formed into the flange configuration illustrated in the drawings. Throughout the specification, the flange portions 28 and 34 and the connections therebetween will be described in detail; however, it should be understood thai the other flange portions are similarly connectqd to the duct end portions and to each other.

The flange portion 28 is illustrated in detail in Figures 2, 3, 4, 8 and 9. The flange 28 has an upstanding channel shaped leg portion generally designated by the numeral 36 with a front wall 38 connected to a rear wall 40 by a generally horizontal top wall 42. A shoulder 43 is formed 3 GB 2 082 282 A 3_ between the walls 40 and 42 and is arranged to receive a longitudinal clip 41 illustrated in Figure 9. Extending laterally at substantially a right angle from the upstanding channel shaped leg portion 36 is a duct receiving leg portion generally 70 designated by the numeral 44 which has a bottom wall 46 and a top wall 48. The top wall 48 has an upturned lip portion 50 to permit the end wall of the duct to slide between the respective walls 46 and 48 so that the duct end wall is frictionally engaged between adjacent surfaces of the flange walls 46 and 48.

In forming the profile of the flange portions, the walls 38 and 40 of upstanding leg 36 are spaced from each other by the top wall 42 to form a longitudinal extending cavity or opening 52 for receiving the legs of angular corner pieces which will be described later. The outer vertical wall 38 has an inturned rebent portion generally designated by the numeral 54 that extends 85 inwardly into the opening 52 closely adjacent the inner surface of vertical wall 40. As illustrated in greater detail in Figure 8, the inturned portion 54 has a tear drop configuration in side elevation with an upper leg 56 and a lower leg 58. The legs 56 and 58 extend angularly from the vertical wall 38 and form an acute angle therewith. The lower leg 58 of inturned portion 54 is spaced upwardly from and entends toward the inner surface 60 of the lower horizontal wall 46 to form therebetween a pocket generally designated by the numeral 62 as seen in Figure 3.

Suitable gasket material 64, as illustrated in Figures 2 and 3, is positioned in the pocket 62 and is maintained therein by the angular relation of lower leg 58 of inturned portion 54 and the bottom horizontal wall 46 and the portion of the inner surface 39 of front wall 38 below the inturned portion 54. The gasket material 64 has a viscosity that permits the material to flow into position by application from a nozzle into the pocket 62. An example material suitable for use as the gasket material 64 is a polymeric material, such as Servaseal 5511 sold by Service Adhesives, Inc. of Maywood, Illinois.

Preferably the gasket material 64 remains flowable for a substantial period of time at least during the assembly of the duct joint. With this arrangement the end portion of the duct when inserted into the duct receiving leg portion 44 partially displaces the gasket material within the pocket 62. The gasket material 64 sealingly connects the duct end portion to the respective flanges. Thus, an air-tight seal is formed around the adjacent metal surfaces as will be explained hereinafter in greater detail.

The vertical rear wall 40 of the upstanding channel shaped leg portion 36 as seen in Figures 3 and 8 extends generally parallel to the vertical front wall 3p to a location where the inner surface 125 of the rear wall 40 is slightly below the lower leg 58 of inturned portion 54. The rear wall 40 at that location is bent to form a juncture with the top wall 48 of the duct receiving leg portion 44. The top wall 48 is inclined to and extends into 130 abutting relation with the upper surface of the lower wall 46 which, in turn, is bent upwardly slightly at its end portion to receive the duct end wall and frictionally engage the duct end wall between adjacent surfaces of walls 46 and 48. The above described configuration permits duct walls of different thicknesses to be utilized and maintained in frictional engagement between the adjacent surfaces of the respective walls 46 and 48.

The vertical dimension of the pocket 62 is not critical because of the gasket material 64 positioned therein. The vertical dimension of pocket 62 may be such that it is arranged to receive euct end walls of different thicknesses and the flange portit s 38-34 may thus be utilized for joint assemblies on ducts of different wall thicknesses. It is preferred, as illustrated in Figure 3, that the duct end walls 22 and 24 be inserted into the pockets 62 and through the gasket material 64 until the edges 22 and 24 of the duct end walls abut the inner surfaces 39 of the vertical walls 38. It should be understood that a seal is obtained when the edge of the duct end wall penetrates the gasket material 64. The gasket material 64 is operable to be displaced and flow out of the pocket 62 at the end of the respective flanges to thereby form a seal around the end of the duct at the intersection of walls 38 and 46 adjacent corner piece 66, as illustrated in Figure 4.

Angular corner pieces 66 according to the present invention, as illustrated in Figures 1-4 and in greater detail in Figures 5-7 and 10 and 11, have a generally planar configuration. Each, corner piece 66 has a body portion 70 with legs 72 and 74 extending angularly therefrom and an upper planar surface 73 and a lower planar surface 75. The corner piece 66 has an elongated concave recessed portion 76, as illustrated in Figures 5, 6, 10 and 11 which extends from a front edge 78 of the leg 72 to the body portion 70 and continues through the body portion 70 along the other leg to a location adjacent a leg end portion 80.

The legs 72 and 74 have apertures 82 therein to permit dimpling of the frame portions after assembly of the frame member 26. The body portion 70 has a bolt aperture 84 arranged to receive a connecting bolt. The body portion 70 terminates in inwardly extending shoulders 86 and 88 adjacent the outer and inner edges 90 and 92 of leg 72. Similarly, the body portion 70 terminates in shoulders 94 and 96 adjacent the outer and inner edges 98 and 100 of leg 74. The shoulders 86, 88, 94 and 96 are arranged to abut ends 102 and 104 of flange portions 28 and 34, as illustrated in Figure 3. The corner piece body portion 70 has a corner section generally designated by the numeral 83 having a flange portion 85, as illustrated in Figures 7 and 10. The flange portion 85 has an arcuate portion 89 which is curved downwardly away from the body portion 70. The flange arcuate portion 89, as illustrated in Figures 5-7, has an upper surface 4 GB 2 082 282 A 4 9 1 and a lower surface 93. The surfaces 9 1 and 93 terminate in longitudinal edge 95.

With the above described arrangement of the corner piece 66, the leg portions 72 and 74 are positioned in the openings 52 of flange portions 38 and 34. The top walls 42 of the upstanding channel shaped leg portions 36 serve as a stop means and abut shoulders 86 and 94 to prevent the body portion 70 of the corner piece 66 from extending into the longitudinal openings 52. With the corner piece 66 in this position as illustrated in Figure 8, the upper surface 91 and longitudinal edge 95 of the downwardly curved flange portion are displaced from the inner surface 39 of the front wall 38 and spaced above the upper surface of horizontal bottom wall 46 so as to provide clearance for the edge 22 of the duct end portion to extend beyond the upper surface 91 of flange portion 85 to a position closely adjacent to or in abutting relation with the inner surface 39 of the front wall 38. With this arrangement an air-tight seal is provided around the corner of the duct end portion adjacent the flanges 28 and 34 and the upper surface 9 1 of the corner piece flange portion 85 by the penetration of a gasket, 90 positioned on the corner piece and adjacent flanges, by the duct edge as will be explained later in greater detail.

As illustrated in Figure 11, the leg 72 of corner piece 66 has the concave recessed portion 76 and the upper and lower edges 90 and 92. When the leg 72 is positioned in the opening 52 of flange portion 28, as illustrated in Figures 3 and 8, the upper edge 90 of leg 72 abuts the under surface of the horizontal wall 42 and the lower edge 92 abuts upper leg 56 of the inturned portion 54. The outer surface of the concave portion 76 abuts the inner surface of the rear wall while the remaining portions of the leg abut the inner surface of the front wall 38. With this arrangement, the leg 72 of the corner piece 66 abuts the surfaces of both the front wall 38 and rear wall 40 in the cavity 52 and the upper edge abuts the horizontal wall 42 while the lower edge 92 abuts the surface of the inturned portion upper leg 56. This provides a rigid, sturdy connection between the corner piece leg portion and the flange portion.

As above described, the shoulders 88 and 96 are arranged to abut the ends 102 and 104 of the flange portions 28 and 34 so that the corner section 83 of the corner piece body portion 70 does not extend into the longitudinal openings 52 of the respective flange portions. Therefore, the downwardly curved flange portion 85 of the corner section 83 is in juxtaposition with the flange portion ends 102 and 104. Further, as illustrated in Figures 4 and 8 the upper surface 91 of the arcuate flange portion 85 at the longitudinal edge 95 is positioned spaced 125 rearwardly from the inner surface 39 of the flange portion front wall 38. Also, the longitudinal edge is spaced above the horizontal inner surface of the flange bottom wall 46. With this arrangement, clearance is provided between the 130 longitudinal edge 95 of the corner piece flange portion 85 and the bottom wall inner surface 60 to permit the edge 22 of duct end portion to pass between the duct receiving walls 46 and 48 and beyond the longitudinal edge 95 and flange surface 9 1. Preferably, the duct edge 22 extends into abutting relation with the inner surface 39 of the flange front wall 38. With this arrangement, as illustrated in Figure 4, the plane formed by the duct end portions 22 and 24 is positioned abovethe plane of the corner piece flange surface 91.

The frame members 26 are formed by first cutting preselected lengths of the strips having preformed flange portion profiles. For example, frame portions 28, 30, 32 and 34 are cut from a strip of the flange shaped profile. Four corner pieces 66 have the leg portions 72 and 74 inserted in the openings 52 in the respective upstanding channel shaped leg portion 36 so that they extend into the openings 52 their entire length with the shoulders 86, 88, 94 and 96 abutting the edges of the respective flange portions. With the corner pieces 66 secured in the openings, the generally rectangular frame 26 is then secured to the end of the duct 12 by passing the duct walls 12-18 between the legs 46 and 48 of the duct receiving leg portion 44. The end portions of the respective duct walls 12-18 are urged into the flange portions 28-34 until the duct end wall portions, for example the end portions 22 and 24, penetrate the gasket material 64 and abut the inner surfaces 39 of the frame portion vertically extending walls 38.

It will be apparent that due to variations in the thickness of the duct end wall portions, the end portions 22 and 24 may be spaced slightly from the front wall 38 but closely adjacent thereto to the extent that the edge of the duct displaces the gasket material 64 in the pocket 62.

Consequently, the flowing type gasket material extrudes outwardly around the upper and lower surfaces of the duct wall portions 22 and 24 to seal the end portion of the duct wall in the respective pocket 62 of the flange portion.

Further, a portion of the gasket material 64 extrudes longitudinally, as illustrated in Figure 4, beyond the ends of the flange portions adjacent the corner piece corner section 83. The gasket material 64 flows between a respective corner piece shoulder portion, for example shoulder 88, and the adjacent flange end portions and onto the flange portion 85. Further when the gasket material 64 is extruded from the open end of the flange it flows into the space between the upper surface of the end of the duct wall and the edge, 95 of the corner piece flange portion 85. This arrangement provides an effective air-tight sear between the flange and the duct and the corner piece and the duct. For purposes of illustration only the gasket material 64 has been omitted from flange portion 34 shown in Figure 4.

As illustrated in Figure 9, pairs of ducts are positioned with the flange members in abutting relation with each other. A suitable relatively thin gasket member 106 such as neoprene, k - GB 2 082 282 A 5 1 polyethylene or the like, is positioned between the upstanding channel shaped leg portion front walls 38 on the outer surface 37 thereof and between the surfaces of the corner pieces 66. Preferably, the gasket member 106 is formed or shaped to meet the dimensions of the duct end wall and the respective frame members 26. Bolts 25 are inserted through the respective apertures 84, and nuts 27 are threadedly secured to the bolts 25 to thus secure the corner pieces 66 to each other and, in turn, secure the respective frame members 26 to each other with the ducts 10 secured thereto.

With this arrangement, the frame members 26 provide a joint assembly for securing the duct members 10 to each other and to form an airtight seal therebetween. The configuration of the flange portions permits duct members having walls of different thicknesses to be utilized with the frame portions having the same dimension. The edges of the duct walls extend into the flowing type gasket material 64 in the longitudinal openings 52 to provide an air-tight seal between the undersurface of the duct wall and the uppersurface of the duct receiving leg portion and further around the duct end wall between the uppersurface of the duct wall and the innersurface 39 of front wall 38. In addition the flowing type gasket material 64 is effective to form an air-tight seal where the surfaces of duct walls or the walls of the frame portions are irregular due to the coating applied to the surface during the galvanizing operation.

Further it will be apparent from the foregoing disclosure that by downwardly curving or displacing the corner piece flange portions 85, the edges 22 and 24 of the duct walls that form the corner piece corner section 83 are operable to extend into or penetrate the gasket member 106 which is positioned between the upstanding channel shaped leg portions 36 in overlying relation with the corner piece corner sections 83. In this manner air from within the duct is - prevented from flowing around the duct end wall and between the upper surface of the duct and the surface of the corner piece flange edge 95.

The flange type duct joint assembly which has been described with reference to the accompanying drawing forms the subject matter of our copending United Kingdom Patent Application No. 7927869 (Publication No. 2 038 434).

Claims (4)

1. Claims 1. A corner piece for connecting a plurality of adjacent flange

   portions for a duct joint, the corner piece comprising a body portion and a pair of legs extending angularly therefrom, said body portion having a corner section with a flange portion extending from said body portion, said flange portion having a first surface and a second surface, said first and second surfaces terminating in an edge portion, and said first and second surfaces of said flange portion being angularly displaced from said body portion.
2. 2. A corner piece as claimed in claim 1, in which said corner section flange portion has an arcuate portion formed by said first and second surfaces.
3. 3. A corner piece as claimed in claim 1 or claim 2, in which said first and second surfaces of said corner section flange portion are curved away from said body portion, and said body portion has a planar surface with said corner section flange portion being curved away from said body portion planarsurface.
4. 4. A corner piece for connecting a plurality of adjacent flange portions for a duct joint, the corner piece being substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

   Printed for Her Majesty's Stationery office by the Courier Press, Leamington Spa, 1982. Published by the Patent Office. 25 Southampton Buildings, London, WC2A 1 AY, from which copies may be obtained.