Abstract:
A corner seal device is disclosed for use in preventing unwanted air leaks in ductwork sections intended for directing conditioned air in heating, ventilating and air conditioning systems (i.e., HVAC systems). The corner seal device eliminates potential air leaks caused inter alia, by the flange members of the ductwork sections, and further, it avoids previously known costly expenses and loss of time to seal the unwanted air leaks created when the flange members of the ductwork sections are made and are prepared for assembly of the ductwork sections. A method of assembly of such ductwork sections incorporating the unique corner seal device of the invention, is also disclosed. A duct for directing conditioned air in heating, ventilating and air conditioning systems incorporating such ducts is also disclosed. A heating, ventilating and air conditioning system incorporating such unique corner seal device and related structures is also disclosed.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. provisional application No. 61/915,348, filed Dec. 12, 2013, the disclosure of which is incorporated in its entirety by reference herein, and made a part of this application. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to the assembly of ductwork sections having channel flanges at their ends. More particularly, the invention relates to a method of assembly of such flanged ductwork sections utilizing a unique sealing bracket which quickly and efficiently seals the assembled ductwork sections such that air leaks are prevented. 
         [0004]    2. Description of the Related Art 
         [0005]    Presently, flanged ductwork sections which are formed with such channel flanges, are assembled by the placement of angle plates into the corners defined by the channel flanges positioned at the ends of the ductwork sections, as more particularly described in U.S. Pat. Nos. 5,283,944, 5,321,880 and 5,342,100 to Goodhue. The contents of U.S. Pat. Nos. 5,283,944, 5,321,880 and 5,342,100 are incorporated in their entirety by reference herein and made a part of this application. 
         [0006]    More particularly, the Goodhue patents relate to angle plates for assembling such ductwork sections having transverse duct flanges by placement of the angle plate into an open space or “notch” in each corner of the duct, the notch being defined by the ends of the transversely oriented flanges of the ducts. Once the angled plates are fully seated in the ductwork flanges, the side edges of the ductwork flanges adjacent the notch are crimped into overlying relation with respect to the angle plate to create a channel so as to assure interlocking of the angle plates with the ducts. 
         [0007]    In practice, the flanges can be structured and dimensioned to provide interlocking of the angle plate, without need for crimping the side edges of the flanges after placement of the angle plate. 
         [0008]    After the angle plates are secured with respect to the ducts, a suitable sealant or gasket is applied to the flange surfaces and the ducts are secured together by bolts passing through each respective pair of face-to-face angle plates and tightened by nuts to provide an airtight seal. 
         [0009]    In general, the assembly of the angle plates with the ductwork sections as described in the Goodhue patents is accomplished by automatic machine operations as described in the Goodhue patents. 
         [0010]    More recently, U.S. Pat. No. 8,875,388, dated Nov. 4, 2014 relates to an apparatus and method for placement of such angle plates in transverse duct flanges of the type described in the Goodhue patents. Moreover, US Published Application No. US 2014/0319165, dated Oct. 30, 2014 relates to an apparatus and method for placement of such angle plates in transverse duct flanges, utilizing a package purportedly for use in the apparatus for automatically assembling the angle plates in the channel shaped flanges. The disclosures of U.S. Pat. No. 8,875,388 and Application Publication No. US 2014/0319165 are incorporated in their entirety herein by reference herein, and made a part of this application. 
       Disadvantages of the Current System of Assembling Flanged Ductwork Sections 
       [0011]    One disadvantage of the present system of assembling such flanged ductwork sections relates to the presence of a notch between the edges of adjacent flanges, and an aperture in each of the corners of the ductwork section between adjacent flanges and adjacent the notch. In practice, the ductwork section is initially formed from a metal such as galvanized sheet steel, and is made into an elongated box-like member of one-piece or multiple-piece construction. The ductwork section will generally have a rectangular cross-section, and for most applications, a square cross-section. Such ductwork can also be made of galvanized steel, stainless steel, aluminum, or any other materials approved by local codes for heating, ventilating and air conditioning systems (hereinafter sometimes referred to as “HVAC” systems). 
         [0012]    To create the flanges, a slit is introduced at each corner of the ductwork section, followed by bending of the marginal portions of the metal adjacent each slit. Since the slits may be made by manually applied cuts in the metal, they are not always identical. Accordingly, when the flanges are formed by bending the respective marginal portions adjacent each slit, the aforementioned notch is formed in the corner of the duct, and a small aperture is often formed where the flanges meet at the duct wall. Since this small aperture in the corners of the duct are potential sources of leaks of conditioned air, in order to avoid such loss of conditioned air, the apertures must be sealed. 
         [0013]    The angle plate is positioned in contact with adjacent flanges and is progressively pressed into contact with the flanges. The marginal edge portions of the flanges extending outwardly of the legs of the angle plate are then crimped over the edge portions of the legs of the angle plate to create a channel which secures the angle plate in position with respect to the ductwork section. 
       The Sealing Step 
       [0014]    Since sealing of the apertures must be accomplished with materials approved for heating, ventilating and air conditioning, the sealants usually applied to the apertures are generally of the type which require a relatively extensive curing time, sometimes up to approximately twenty-four hours. Therefore it can be readily appreciated that such twenty-four hour period provides a relatively significant delay in the production schedule of the ductwork sections. 
         [0015]    I have invented a corner seal device which is quickly applied to each of the four corners of the ductwork assembly so as to extend across the notch between the orthogonal flanges, while at the same time, sealing the unwanted air leaks created by the duct forming slits, thereby resulting in improved efficiency for assembly and operation of such ductwork sections. My invention also relates to improvements in such ductwork, and an improved method of assembling such ductwork, which method is cost effective and which eliminates costly labor expenses. My invention therefore improves such air conditioning systems which incorporate such ductwork sections. 
       SUMMARY OF THE INVENTION 
       [0016]    The present invention relates to a corner seal device for ductwork for conditioned air, and a method of assembly of such ductwork in which known potential air leaks are readily prevented when the ductwork sections are connected together to direct conditioned air in an air conditioning and/or heating system. 
         [0017]    In particular, the corner seal device is assembled with the ductwork sections and corner mounting angle plates for use in connecting ductwork sections in a system which is free of air leaks. 
         [0018]    The corner seal device of the present invention eliminates costly time delays and expenses by providing a quick connecting seal device which eliminates loss of conditioned air. 
         [0019]    A device for sealing a space defined between respective end portions of an adjacent pair of orthogonal flange members of a conditioned air duct having a generally rectangular cross-section is disclosed, which comprises, a first plate member having a surface dimensioned and configured for placement in face-to-face relation with the respective adjacent upper surface portions of said adjacent flange members, and a leg member extending away from a generally central portion of said plate member and being generally perpendicular thereto, the leg member comprising second and third orthogonal plate members having respectively orthogonal surface portions configured and dimensioned to engage corresponding respective adjacent orthogonal inner wall surface portions of said duct when said first plate member is positioned on the flange members. 
         [0020]    According to the invention, the leg member is generally integrally attached to the plate member, or monolithically formed therewith. 
         [0021]    The first plate member and the leg member are preferably made of at least one of a metal and plastic. The metal may be steel, galvanized steel, stainless steel or aluminum, for example. 
         [0022]    The surface portions of the first plate member and the leg member which are adapted to contact the respective flange members and the corresponding respective inner wall surface portions of the duct are coated with adhesive sealing material for attachment to the respective surface portions, so as to cover and seal the space between the flange members to prevent leakage of conditioned air therethrough. 
         [0023]    The adhesive sealing material should be approved for heating, ventilating and air conditioning systems. Furthermore, the first plate member is preferably configured to define a pair of orthogonal sections dimensioned for respective face-to-face engagement with the corresponding pair of orthogonal flange members, and the second and third plate members of the leg member are configured, dimensioned and positioned for face-to-face engagement with the corresponding orthogonal inner wall surface portions of the duct adjacent the corner of the duct. 
         [0024]    The first plate member is preferably provided with at least one attachment device for attachment of the plate member in position with respect to the orthogonal flange members and the wall portions of the duct. Further, the angle plate member is attached to the flange members at the corner of the duct, and the at least one attachment device of the first plate member is configured and dimensioned for locking attachment to the angle plate. 
         [0025]    The attachment device of the invention is preferably comprised of a pair of locking attachment prongs extending perpendicular to the plate member, and being configured to enter correspondingly dimensioned apertures in the corner angle plate. The locking attachment prongs are configured and dimensioned to become resiliently engaged with the apertures in the angle plate to retain the first plate member and the second and third plates of the leg member in position with respect to the ductwork. 
         [0026]    The at least one attachment device may also be comprised of upstanding side walls dimensioned, configured and adapted to resiliently engage the flange members of the duct to attach the plate member and the leg member to the duct. In all embodiments disclosed, the rectangular shaped conditioned air also contemplates a duct having a square cross-section. 
         [0027]    A sealing device is also disclosed for sealing flanged sections of ductwork attached together with the flanges positioned in face-to-face relation to fond a continuous duct system for conducting conditioned air, the flanges being respectively oriented at right angles to each other and to the ductwork, the flanges defining at least one aperture between their end portions, which may permit leakage of conditioned air therethrough, which comprises a leg member having generally orthogonal plate members adapted to be positioned in engagement with adjacent corner wall portions of the ductwork section, the leg member further having a plate member integrally attached thereto and generally perpendicular thereto, the plate member being configured and dimensioned to be placed in face-to-face relation with respective adjacent surface portions of the flanges. The leg member and the plate member are respectively provided with a soft sealing material on all surfaces coming into contact with the respective surface portions of the ductwork when inserted into the corner of the ductwork to prevent leakage of conditioned air. 
         [0028]    A duct is also disclosed for directing conditioned air in a heating, ventilating and air conditioning type system, which comprises a first ductwork section having a generally rectangular cross section, each corner of the rectangular ductwork section having a pair of channel flanges extending orthogonally from the respective duct walls and orthogonally with respect to each other. The end portions of the adjacent flanges define an open space at each corner of the ductwork section. An angle plate is seated at each corner of the ductwork section in the channel flanges for attaching the first section of ductwork to a second identical section of ductwork, each angle plate including two legs formed together in angular relation by an integral corner. 
         [0029]    A device is provided for sealing the open space between said flanges, the device comprising, a first plate member having a surface portion dimensioned and configured for placement in face-to-face relation with the respective adjacent upper surface portions of the adjacent orthogonal flanges, and a leg member extending generally from, and generally perpendicular to a central portion of said plate member, the leg member being comprised of respective orthogonal second and third respective plate members having surface portions configured and dimensioned to engage corresponding respective adjacent orthogonal inner wall surface portions of said ductwork section when the plate member is positioned on the flange members, thereby providing an airtight seal for at least a portion of the open space between the flange members. 
         [0030]    A method of attaching two sections of flanged ductwork so as to provide an airtight duct for conducting conditioned air in a heating, ventilating and air conditioning system, the ductwork sections having a generally rectangular cross-section and the flanges of the ductwork being generally orthogonal to each other is disclosed, comprising a) positioning an angle plate into contact with one corner of a first ductwork section and progressively pressing the angle plate into the flanges, the angle plate including two legs formed together in angular relation, the flanges defining an open space between their respective ends, and further, having side edge marginal portions adjacent said each leg of said angle plate, b) crimping the marginal side edge portions of the flanges over each leg of the angle plate to form a channel which positively locks the angle plate with respect to the adjacent flanges, c) positioning a device for sealing the open space between the flanges, the device comprising a plate member having a surface dimensioned and configured for placement in face-to-face relation with the respective adjacent upper surface portions of the adjacent flanges, a leg member extending away from a generally central portion of the plate member and being generally perpendicular thereto, the leg member having orthogonal surface portions configured and dimensioned to engage corresponding respective adjacent orthogonal inner wall surface portions of the duct when the plate member is positioned on the flanges. At least one attachment device is provided for attachment of the plate member in position with respect to the flanges, and an adhesive sealing material is provided on all surface portions of the plate member and the leg member which contact the flange member and the surface portions of the duct walls. 
         [0031]    The method also comprises repeating the steps a), b) and c) on the remaining corners of the first ductwork section, and then repeating all of the previously recited steps on the second section of ductwork, positioning the first and second sections of ductwork in end-to-end relation by positioning the flange members in face-to-face relation, and inserting at least one bolt-type fastener through respective aligned apertures of adjacent angle corners of the first and second ductwork sections, and securing the ductwork sections together with a nut-type fastener over each the bolt-type fastener at each corner of the ductwork sections. 
         [0032]    A heating, ventilating and air conditioning system which includes ductwork for conducting conditioned air therethrough, said ductwork structured and configured according to the invention as disclosed herein. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0033]    Preferred embodiments of the invention are described herein with reference to the drawings, wherein: 
           [0034]      FIG. 1  is a perspective view of two sections of flanged ductwork having a corner mounting angle plate attached at each corner of the respective ductwork sections, and positioned for engagement with each other and attachment by suitable fasteners to produce a continuous duct system for conditioned air; 
           [0035]      FIG. 2  is an enlarged top perspective view of the assembled corner mounting angle plate and flanged section of ductwork which is encircled by dash lines in  FIG. 1 , and which is intended to be attached to an identical flanged section of ductwork therebelow, as illustrated by arrows A, B and C in  FIG. 1 , the view in  FIG. 2  illustrating the notch between adjacent orthogonal flanges and the aperture in the corner between the respective flange formations which can potentially result in an unwanted air leak in the ductwork; 
           [0036]      FIG. 3  is a top perspective view of one preferred embodiment of a corner seal device constructed according to the present invention, this device having an adhesive-type approved sealant on the relevant surfaces, and being intended to be attached to a flanged section of ductwork of the type shown in  FIGS. 1 and 2 , to extend across the notch created when the flanges are formed, and seal the small aperture between the flanges of the ductwork; 
           [0037]      FIG. 4  is an enlarged top perspective view, with parts separated, of a flanged section of ductwork prior to assembly with a corner mounting angle plate and the corner seal device constructed according to the present invention; 
           [0038]      FIG. 5  is an enlarged top perspective view similar to  FIG. 4 , but of the opposite side of the ductwork, illustrating the flanged ductwork of  FIG. 4 , assembled with the corner mounting angle plate, and ready for assembly with the corner seal device of the present invention, shown immediately thereabove; 
           [0039]      FIG. 6  is a top plan view of the corner seal device of the present invention, illustrating one preferred embodiment, provided with dual facing locking attachment prongs; 
           [0040]      FIG. 7  is a top perspective view of the assembled corner portion of the flanged section of ductwork of  FIGS. 4 and 5 , assembled with the corner mounting angle plate shown in  FIG. 4 , and further, with the corner seal device of  FIG. 3 , shown in phantom lines; 
           [0041]      FIG. 8  is a top plan view of the assembled components of  FIG. 7 , showing the corner seal device of the present invention in cross-section; 
           [0042]      FIG. 9  is a partial cross-sectional view, taken along lines  9 - 9  of  FIG. 8 , illustrating one corner of the two items of flanged ductwork shown in  FIGS. 7 and 8 , assembled together with corner angle plates and corner seal devices of the present invention, together with the addition of a bolt and nut, this assembly being part of a leak-proof ductwork system for conducting conditioned air, without loss of such conditioned air; 
           [0043]      FIG. 10  is a cross-sectional view, taken along lines  10 - 10  of  FIG. 8 , illustrating one preferred embodiment of locking attachment prongs of the corner seal device of the present invention in locking engagement with the corner angle plate; 
           [0044]      FIG. 11  is a top view, partially cut away, of an assembled ductwork corner similar to  FIGS. 7 and 8 , showing an alternative embodiment of the corner seal device of the present invention, incorporating an alternative arrangement of locking attachment prongs, said prongs being in perpendicular relation with each other in this embodiment; 
           [0045]      FIG. 12  is a top plan view similar to  FIG. 11 , showing yet another alternative embodiment of the corner seal device of the present invention, and incorporating yet another alternative arrangement of the locking attachment prong feature, this arrangement being in the form of a single locking attachment prong having a locking head having opposed sloped surfaces for insertion into an appropriately dimensioned and configured elongated slot in interference relation with the elongated slot provided in the corner mounting angle plate for locked engage relation with the slot; 
           [0046]      FIG. 13  is a cross-sectional view, taken along lines  13 - 13  of  FIG. 12 , illustrating the engagement by the single attachment locking prong of the corner seal device of the invention shown in  FIG. 12 , with the corner angle mounting plate of the assembly; 
           [0047]      FIG. 14  is a top perspective view of yet another alternative embodiment of the corner seal device of the present invention, incorporating a relatively soft plastic material having self-sealing surfaces somewhat similar to so-called “orange peel”-type surfaces, such orange peel-type surface having a plurality of randomly positioned and spaced “bumps” and “valleys”, which provide self-sealing when placed in engagement with the relatively flat surfaces of the ductwork and associated flanges, this embodiment eliminating the need for an additional sealant; 
           [0048]      FIG. 15  is a partial cross-sectional view, taken along lines  15 - 15  of  FIG. 14 ; 
           [0049]      FIG. 16  is a top plan view, partially in cross-section, of one corner of a section of flanged ductwork having the corner seal device of the present invention as shown in  FIGS. 14 and 15 , placed in position in the ductwork section as shown in the previous views; 
           [0050]      FIG. 17  is a top perspective view of yet another alternative embodiment of the corner seal device of the invention, including edgewise locking attachment prongs arranged to engage and grip the respective edges of the ductwork flanges to attach the corner seal device to the ductwork; 
           [0051]      FIG. 18  is a top plan view of an assembled corner section of ductwork similar to  FIG. 8 , incorporating the corner seal device of  FIG. 17 ; and 
           [0052]      FIG. 19  is a cross-sectional view taken along lines  19 - 19  of  FIG. 18 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0053]    In the description which follows, reference is sometimes made to a corner structure of a conditioned air duct. Such descriptions are illustrative of a typical corner of the ductwork. Each such section of ductwork which has a rectangular section generally has four of such corner structures. The expression “rectangular” duct section is also meant to contemplate such duct sections having a square cross-section. 
         [0054]    Referring initially to  FIG. 1 , there is shown a pair of flanged ductwork sections  10 , 12  positioned for attachment in end-to-end relation as shown by the arrows A, B, and C, with suitable fasteners according to known practice. The faces of each such section of ductwork are to be attached in face-to-face relation. In general, the ductwork sections are attached to each other by positioning the ends in face-to-face relation and by passing a bolt through apertures  16  of the known corner mounting angle plates  14  similar to the angle plates disclosed in U.S. Pat. Nos. 5,283,944, 5,321,880 and 5,342,100. In general, the ductwork sections and the corner mounting angle plates are usually made of steel which may be galvanized, and the ductwork sections are usually of square cross-section. However any approved materials for such ductwork and attachment devices is contemplated herein. 
         [0055]      FIG. 2  is an enlarged top perspective view of the assembled corner mounting angle plate and flanged section of ductwork which is encircled in  FIG. 1 . The ductwork is generally rectangular, and often square in cross-section, such that each section of ductwork will include four of such corner structures as shown. 
         [0056]    In  FIG. 2 , ductwork section  10  is provided with example flanges  18 ,  20  which are bent away approximately 90° from the ductwork walls as shown. As noted, the steel ductwork can be of one piece or multiple piece construction. After formation of the basic duct, a cut is introduced at each corner, and the flanges are formed by bending the marginal portions at an approximate angle of 90° to the duct wall, leaving rectangular corner notch  25  defined by flange edges  21 ,  23 . Due to occasional inconsistencies in the depth of the cut made in the ductwork corner, when the flanges are bent, a small aperture  19  is often formed, which is potentially a source of leakage of the conditioned air which is directed through the ductwork sections. 
         [0057]    To prevent loss of conditioned air (and consequent energy loss) a suitable approved sealant is generally applied to aperture  19  and then permitted to cure. In particular, the sealant must be approved for all HVAC (i.e., heating, ventilating, and air conditioning) systems. Since curing time for such approved sealants can take up to 24 hours, the application of the sealant, combined with the loss of time for the sealant to be cured, results in a measurable inefficiency in the method of assembling and constructing such ductwork systems. 
         [0058]    To eliminate the unwanted air leaking aperture  19 , a corner seal device  24  as shown in  FIG. 3  will be incorporated into the assembly of the flanged ductwork section as will be described. As can be seen, the corner seal device can be readily applied to the assembly of the angle plate and the ductwork flanges prior to completing the attachment of the ductwork sections. 
         [0059]    Further sealing of the entire assembly is generally provided by a suitable strip of soft gasket material  22 , generally of approximately ⅛ inch thickness, adhesively applied to the flanges  18 ,  20  to be positioned between them in sealed relation. In general, the gasket material may be self-sticking, or it may be provided with an additional adhesive layer covered by a suitable silicone release paper or the like. 
         [0060]    In  FIG. 3 , the corner seal device  24  constructed according to the present invention is shown. The corner seal device  24  is preferably made of one piece, such as metal or a plastic material which meets national and local air conditioning and heating codes. The corner seal device may be of one piece construction as shown; however, multiple pieces attached to form an integral seal are also contemplated. The corner seal device can be made of galvanized steel, stainless steel, aluminum or plastic. While metal or plastic is primarily contemplated for the corner seal device, alternative materials which meet local HVAC standards are also contemplated. 
         [0061]    Referring to  FIG. 3 , the corner seal device  24  includes a first plate member  27  and a leg member  35  comprised of second and third plate members  31 ,  33 , formed adjacent and monolithically with plate member  27 . Plate member  27  is perpendicular to second and third plate members  31 ,  33 , as shown, and second and third plate members  31 ,  33  are orthogonal to each other so as to engage the perpendicular duct walls at each former of the ductwork section. 
         [0062]    In the preferred embodiment shown in  FIG. 3 , the respective surfaces of the plate members  31 ,  33  are coated with a suitable adhesive sealing material  28  of a type approved for use in heating and air conditioning codes. The sealing material is depicted by the stippled portions on the respective surfaces as shown in  FIG. 3 . 
         [0063]    One embodiment of the seal device  24  shown in  FIG. 3 , includes a pair of upstanding resilient locking attachment prongs  30 ,  32  which are positioned to be inserted into correspondingly shaped rectangular apertures  34 ,  36  in the corner mounting angle plate  14  as will be described in more detail in connection with  FIGS. 4-9 . 
         [0064]    In  FIG. 4  there is shown an enlarged view, with parts separated for illustration purposes, of a corner of a flanged section of ductwork  10  prior to assembly with a corner angle plate  14  and a corner seal device  24  of the present invention. Ductwork section  10  is in position to be assembled with corner mounting angle plate  14  as shown in  FIG. 5 . Corner seal device  24  of the present invention is then attached to the inside corner of the ductwork section  10 , covering a portion of the space defined as corner notch  25 , which in turn is defined by flange edges  21 ,  23 , as shown in  FIG. 4 . 
         [0065]    In the embodiment shown in  FIGS. 3-6 , the corner seal device  24  has a coating of suitable approved adhesive sealing material  28  on the inner surfaces as shown, which will adhere to the ductwork section between the flanges  18 ,  20 , while covering not only a part of the corner notch  25 , but also sealing unwanted aperture  19  in the ductwork. 
         [0066]      FIG. 7  is a top perspective view of the corner portion of the flanged section of ductwork  10  of  FIG. 1 , assembled with the corner mounting angle plate  14  shown in  FIGS. 1 and 4 , and with the addition of corner seal device  24  of the invention (is shown in phantom lines) installed to cover aperture  19  which is shown more clearly in  FIG. 2 . As well, a portion of the space defined by corner notch  25  will also be covered by the seal device of the present invention. 
         [0067]      FIG. 8  is a top plan view of the assembled components shown in  FIG. 7 , showing the corner seal device  24  of the invention, attached to corner mounting angle plate  14  by engagement of upstanding attaching locking prongs  30 ,  32  with corner mounting angle plate  14  by insertion thereof into rectangular apertures  34 ,  36  in corner mounting angle plate  14  as shown. 
         [0068]      FIG. 9  is a partial cross-sectional view, taken along lines  9 - 9  of  FIG. 8 , showing one assembled corner of the components of  FIGS. 7 and 8 , assembled together with bolt  37  through aperture  35  and nut  39  to form part of a leakproof ductwork system for conditioned air. Identical corner seal devices  24  of the present invention are shown in opposed relation and in cross-section, attached to corner mounting angle plates  14  by upstanding attachment locking prongs  30  in apertures  34 . The locking prongs  30 ,  32  and respective apertures  34 ,  36  are shown more clearly in  FIG. 10 . 
         [0069]      FIG. 10  is a cross-sectional view taken along lines  10 - 10  of  FIG. 8 , illustrating the attachment locking prongs  30 ,  32  of the corner seal device of the present invention in locking engagement with the angled corner mounting angle plate  14  through respective apertures  34 ,  36 . 
         [0070]      FIG. 11  is a top view, partially cut away, and partially in cross-section, of an assembled ductwork corner similar to  FIGS. 5, 7 and 8 , showing an alternative embodiment of the corner seal device  42  of the present invention, incorporating an alternative arrangement of the locking attachment prongs  44 ,  46 , oriented at approximately 90° to each other and inserted into respective apertures  48 ,  50  in corner mounting angle plate  42  to seal aperture  19  formed between flanges  18 ,  20  as disclosed previously. 
         [0071]      FIG. 12  is a top plan view, partially cutaway, similar to  FIG. 11 , showing yet another alternative embodiment of the corner seal device  52  of the present invention, incorporating a single upstanding attachment locking prong  54  dimensioned and positioned for insertion in interference relation into correspondingly positioned and dimensioned aperture  56  for locking attachment as shown in cross-section in  FIG. 13 . 
         [0072]      FIG. 14  is a top perspective view of yet another alternative embodiment of the corner seal device  60  of the present invention, wherein the sealing surfaces are made of a relatively soft and resilient self sealing material having “orange peel”-type surfaces  62  comprised of a soft material defining a plurality of randomly positioned and randomly configured bumps  64  and valleys  66 , which provide a self-sealing effect when positioned in engagement with the respective relatively smooth and flat surfaces of the corner mounting angle plate and the ductwork section as disclosed in the previous embodiments. The self-sealing effect is primarily due to the configurations of the bumps  64  and valleys  66 , combined with the soft character, the flexibility, and the resilience of the material, which is preferably a plastic material. This embodiment includes locking attachment prongs  61 ,  63  as shown in  FIG. 14 . 
         [0073]      FIG. 15  is a partial cross-sectional view taken along lines  15 - 15  of  FIG. 14 . 
         [0074]      FIG. 16  is a top plan view partially in cross-section, of the corner seal device of  FIGS. 14 and 15  of the present invention, attached in position with respect to a section of ductwork  10  of the type shown in  FIG. 1 , and showing the sealing effect of the “orange peel-type” surfaces  62  comprised of relatively soft bumps  64  and valleys  66 , in engagement with the relatively smooth surfaces of the ductwork walls and flanges. 
         [0075]      FIG. 17  is a top perspective view of yet another embodiment of a corner seal device  70  of the present invention, incorporating alternative attachment locking prongs  72 ,  74 , dimensioned and positioned for locking engagement with the flange members  18 ,  20  of the ductwork section  10  of  FIG. 1 , as shown in  FIGS. 18 and 19 . This system of attachment locking prongs provides stable attachment of the corner seal device  70  with respect to the corner mounting angle plate and the ductwork flanges. 
         [0076]      FIG. 18  is a top plan view of a ductwork assembly incorporating the corner seal device of  FIG. 17 . 
         [0077]      FIG. 19  is a cross-sectional view taken along lines  19 - 19  of  FIG. 18 . 
         [0078]    It can be readily appreciated that upon assembly of such ductwork sections with angle plates, and upon assembling the sections to form continuous ductwork for HVAC systems, the relatively quick insertion of the corner seal device of the present invention, in position as described, provides a unique advantage over the prior art methods of assembly. In particular, such corner seals can be made readily available to the user, with sealing material applied in advance. The sealing material can be covered with an appropriate release paper, i.e., silicone release paper, such that the assembler can quickly select a corner seal, peel the release paper, and then simply drop it into position in the corner of the respective flanged ductwork sections as described. 
       LIST OF REFERENCES 
       [0000]    
       
         
           
               10 ,  12  Ductwork Sections 
               14  Corner Mounting Angle Plate 
               16  Apertures in Angle Plate 
               18 ,  20  Ductwork Flanges 
               19  Small Aperture/Air Leaking Aperture 
               21 ,  23  Flange Edges 
               22  Soft Gasket Material 
               24  Corner Seal Device 
               25  Corner Notch 
               27  Monolithically Formed Plate Member of Corner Seal Device 
               28  Adhesive Sealing Material of Corner Seal Device 
               30 ,  32  Pair of Upstanding Resilient Locking Attachment Prongs of Corner Seal Device 
               26  Leg Member of Corner Seal Device  24 , Comprised of Plate Members  31 ,  33   
               31 ,  33  Plate Members of Leg Member  35  of Corner Seal Device 
               34 ,  36  Rectangular Apertures in Corner Mounting Angle Plate  14   
               35  Aperture in Corner Angle Plate for Bolt  37   
               37  Bolt 
               39  Nut 
               42  Alternative Embodiment of Corner Seal Device 
               44 ,  46  Locking Attachment Prongs of Alternative Corner Seal Device  42   
               48 ,  50  Apertures in Corner Mounting Angle Plate of  FIG. 11   
               52  Alternative Embodiment of Corner Seal Device 
               54  Single Upstanding Locking Attaching Prong of Corner Seal Device  52   
               56  Correspondingly Positioned and Dimensioned Aperture for Reception of Locking Prong  54   
               60  Alternative Embodiment of Corner Seal Device 
               61 ,  63  Locking Attachment Prongs 
               62  Orange Peel-Type Self-Sealing Surface 
               64 ,  66  Respective Randomly Configured Bumps and Valleys in Orange Peel-Type Surface  62   
               70  Alternative Embodiment of Corner Seal Device 
               72 ,  74  Alternative Locking Attachment Prongs of Corner Seal Device  70  of  FIG. 17