Abstract:
An apparatus for coupling and sealing tubes, comprising a flexible duct having a first and second end portions, each portion having an outwardly extending seal portion connected to a flat portion, which in turn is connected to an angled portion which connects to a flat portion having expanded diameter. The apparatus also comprises a sealing assembly comprising a split ring, a compression ring and an end cap subassembly which fits over the compression and split rings. The end cap subassembly comprises a pair of half-rings which are hinged together at one end and latched together using a closure mechanism at the other end. The split ring is mounted over the duct end seal after a tube with a bead is inserted inside the duct. A compression ring is fit over the split ring and the end cap subassembly is latched in place over the compression and split rings, thereby placing the duct seal portion under compressive pressure against the tube and maintaining it in place in a sealed relationship.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to sealing systems. More particularly, the present invention relates to a flexible duct seal and compression assembly which reduces potential leakage and slippage.  
       BACKGROUND OF THE INVENTION  
       [0002]     Present day flexible ducting is constructed using rubber, fabric reinforced rubber (for example, flexible ducts available from RCF Technologies, Inc., Vidalia, Ga., www.rcftechnologies.com) or flexible plastics secured to metal or rigid tubing by means of commercially available band clamps or welding. Sealing against fluid as well as against internal or external pressure and slippage are important functions of the clamp.  
         [0003]     One typical type of band clamp consists of a metal strip with helical slots at one end. The slots slip through a worm gear located at the opposite end. The strip is wrapped around a tubular end section of the duct which has been placed over a beaded metal tube to which it is secured. The strip is fed through the worm gear and tightened until the duct is locked in place and sealed. Where higher pressures are involved, the duct may, in time, slip out from under the clamp. Hence, a bead is provided at the end of the tube to act as a stop.  
         [0004]     As the band or strip is drawn through the worm gear and tightened, friction between it and the duct material causes the duct material to move with the strip and gather near the worm gear. This can create a leak path and many designs of band clamps have been developed to address this problem, with varying degrees of success.  
         [0005]     It would be desirable to have a duct sealing system that would adequately address the problem of slippage and leakage. Furthermore, it would be desirable to have a sealing system that would not require manual tightening.  
       SUMMARY OF THE INVENTION  
       [0006]     Generally described, the present invention provides in a first exemplary embodiment a sealing apparatus generally comprising a flexible duct and a sealing assembly. The duct comprises i) a first end having an annular first seal extending radially therefrom, the first seal having a rounded side edge, ii) a first generally flat portion extending from the first end, iii) an expanded portion having an expanded diameter extending from the generally flat portion, iv) a second generally flat portion extending from the expanded portion, and, v) a second end having an annular second flange extending radially therefrom, the second flange having a rounded side edge. The invention further comprises a sealing assembly, comprising a split ring, at least one compression ring, and an end cap assembly. The split ring comprises a ring having a gap therein. The compression ring has a rim sized to fit over the first end seal or the second end seal in a friction fit. The end cap subassembly comprises a) an end cap ring, comprising a first and second sections, each section having a first end and a second end, b) a rim extending from the end cap ring, c) a lip extending inwardly from the rim and generally parallel to the end cap ring, d) a hinge joining the first ends of the first and second sections, and, e) a closure for removably maintaining the second ends in a fixed spaced relationship.  
         [0007]     The duct is designed so that each opening can fit over a tube having a beaded or flanged end. The apparatus of the present invention seals over the tube and allows for flexion of two tubes with respect to one another in the event of stress, expansion, vibration or the like. The end cap locks the duct over the beaded end of the tube to reduce the likelihood of the duct being pulled off the tube. The end cap secures the seal into the compression ring so that it resists pressure and vibration.  
         [0008]     Other features and advantages of the present invention will become apparent upon reading the following detailed description of embodiments of the invention, when taken in conjunction with the appended claims. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]     The invention is illustrated in the drawings in which like reference characters designate the same or similar parts throughout the figures of which:  
         [0010]      FIG. 1  is a cross-section view of one exemplary embodiment of the present invention showing a flexible duct and sealing assembly in use with a pair of conventional tubes.  
         [0011]      FIG. 2  is a perspective view of a duct according to one exemplary embodiment.  
         [0012]      FIG. 3  is a side elevation view of an exemplary embodiment of a split ring.  
         [0013]      FIG. 4  is a detailed view of the edge of the split ring of  FIG. 3 .  
         [0014]      FIG. 5  is a side elevation view of an exemplary embodiment of a compression ring.  
         [0015]      FIG. 6  is a detailed view of the edge of the compression ring of  FIG. 5 .  
         [0016]      FIG. 7  is a front elevation view of one exemplary embodiment of an end cap subassembly.  
         [0017]      FIG. 8  is a side elevation view of the end cap subassembly of  FIG. 7 .  
         [0018]      FIG. 9  is a front elevation view of an alternative exemplary embodiment of an end cap subassembly.  
         [0019]      FIG. 10  is a side elevation view of the end cap subassembly of  FIG. 9 .  
         [0020]      FIG. 11  is a side elevation view of an alternative embodiment. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]      FIG. 1  shows a conventionally available rigid first tube  4  and second tube  6 , each of which has a bead  8 ,  10  proximate to one end. The tube is used in many industries and is available from a number of different sources.  
         [0022]     A flexible duct sealing apparatus according to a first exemplary embodiment of the present invention and shown in  FIG. 1  generally comprises a duct  14  and a sealing assembly  20 , generally comprising a split ring  22 , a compression ring  24  and an end cap assembly  26 . Typically, a pair of sealing assemblies  20  will be used with a single duct  14  so as to join two tubes  4 ,  6  together. It is contemplated as being within the scope of the present invention to adapt the duct  14  construction to have more than two openings so as to join more than two tubes together, thus employing more than two sealing assemblies  20 .  
         [0023]     The duct  14  is formed of a flexible material designed to operate at the parameters desired. A preferred duct is the Rishon® duct available from RCF Technologies, Inc., Vidalia, Ga., which is formed of multiple layers of rubberized material. It is preferable that the duct  14  be able to withstand appropriate levels of temperature, pressure or caustic material as the intended use or environment requires. The duct  14  has a first end  30  having an opening  32  sized to receive tube  4 . A first seal  34  having a rounded edge  36  is connected to a generally flat section  38 , which in turn is connected to a beveled section  40 . The beveled section  40  is connected to a generally flat middle section  42 . At the opposite end of the duct  14  are second end  44 , opening  46 , second seal  48 , rounded edge  50 , beveled section  51 , and flat section  52 , which are substantially mirror images of the correlative parts at the first end  30 . It is contemplated as being within the scope of the present invention that the components at each end may be the same in size and shape, or may be different, such as when two different diameter or shaped tubes  4 ,  6  are to be connected. In a preferred embodiment the duct has a circular cross-sectional shape; however, other shapes, such as, but not limited to, oval, elliptical, T-shaped, elbows, involuted or the like are possible.  
         [0024]     In one exemplary embodiment the duct  14  has a reinforcing band  60  associated with the flat section  38 . The association can be such that the band  60  is on the outside of the duct  14 , or, more preferably, the band  60  can be incorporated in between layers of the duct material. Where the duct is formed of two layers, the band  60  can be manufactured to be between the inner and outer walls of the material. The function of the band  60  is to provide additional reinforcement to the duct  14  when in use in high stress environments, e.g., high pressure or vacuum. The band  60  can be made of solid metal, metal mesh, wire or fabric, plastic, combinations of the foregoing, or other suitable material. It is to be understood that a plurality of bands  60  can be used, with each band  60  being parallel, crossing or overlapping with respect to a neighboring band.  
         [0025]      FIGS. 3 and 4  show the split ring  22 , which preferably comprises a single piece ring having an opening  62  which can be twisted so that ring  22  can be fit over the duct  14  and positioned around the flat section  38  or  52  (as shown in  FIG. 1 ).  FIG. 4  shows a detailed cross-section view of the rim of the ring  22 , which has a lip section  64  and a flange  66 . The lip  64  preferably has a beveled edge  68 , which, when the ring  22  is positioned against the seal  34  or  48 , reduces the possibility of cutting the duct  14 . The seal  66  has a notch  70  which, as will be described in greater detail hereinbelow, mates with the compression ring  24 . The height of the flange  66  preferably is approximately the same or slightly less than the height of the seal  34 ,  48 . The ring  22  creates an interference fit with the bead, preventing slippage.  
         [0026]      FIGS. 5 and 6  show the compression ring  24 , which comprises a ring  72  having a lip  74 .  FIG. 6  shows a detail of the lip  74 , which preferably has a beveled or rounded edge  76  which fits within the notch  70  of the split ring  22 . The compression ring  24  is preferably sized to fit snugly over the seal  34  or  48  of the duct  14  so as to squeeze the rounded edge  36  or  50  towards the tube  4  or  6 , thereby creating a tight seal between the duct  14  and the tube  4  or  6 . The split ring may be eliminated for low pressure applications.  
         [0027]      FIGS. 7 and 8  show one exemplary end cap subassembly  80  in which a pair of ring segments  82  and  84  are pivotably joined by a hinge  86 . The hinge comprises two hinge segments  88 ,  90 , with segment  88  being affixed to ring segment  82  and hinge segment  84  being affixed to ring segment  84 . A pin  92  connects the hinge segments  88 ,  90 . A latch or lock mechanism  94  removably joins the other ends of the ring segments  82 ,  84 . Any suitable conventional latch or lock mechanism which can maintain the ring segments in a fixed relationship may be used with the present invention. See for example, the CentraLock™ mechanism by RCF Technologies, Inc. disclosed in U.S. Pat. No. 5,865,476, the disclosure related thereto being incorporated by reference herein.  
         [0028]     In an alternative exemplary embodiment of the end cap, shown in  FIGS. 9 and 10  (as an oval shape, but circular other shapes are usable), an end cap subassembly  100  comprises a ring base segment  102 , a first ring segment  104  and second ring segment  106 , the ring segments  104 ,  106  being hingedly attached to the base segment  102  by hinges  108 ,  110 . The hinges may be similar in design to the hinge  86 . The ring segments  104  and  106  are joined together by a latch or lock mechanism  94 . The end cap subassembly  100  is used in a manner similar to the end cap subassembly  80 . This ring configuration is particularly well adapted for use where there is reduced clearance to open the ring segments. One exemplary embodiment of a latch mechanism  94  that can be used is shown in U.S. Pat. No. 5,865,476, the disclosure of which is incorporated herein.  
         [0029]     In operation a tube  4  is fitted into the opening  32  of the duct  14  so that the bead  8  is inside the duct  14  and the flange  40 . A split ring  22  is fitted over the duct  14  and placed over the flat section  38  so that the flange  66  is pointed away from the opening  32 . A compression ring  24  is fitted over the split ring  22  and force fitted over the seal  34 . The rounded edge  36  deforms slightly, which assists in assembly and in providing a tight seal. An end cap assembly  26  (with the latch mechanism unlatched) is fitted over the compression ring  24  and the flange  66  of the split ring  22  and the latch  94  is closed and locked. The compression ring  24  presses the inside of the duct  14  against the outside of the tube  4 . A second set of the split ring, compression ring and end cap subassembly are fit over the second end  44  in a similar manner. If the duct  14  is designed to have more than two openings and flanges, etc., then there is one sealing assembly  20  used for each opening.  
         [0030]     In an alternative exemplary embodiment of the present invention the duct  14  can be modified to have two sealing assemblies  20  used at each end where additional sealing is required.  
         [0031]     In a further alternative exemplary embodiment, shown in  FIG. 11 , a duct  110  is modified in that the rounded edge  36 ,  50  of  FIG. 1  is, instead, a generally U-shaped groove  112 . Either edge  36  or edge  50  or both edges can have a groove  112 . The groove  112  can accommodate a conventional O-ring  114  such that when the compression ring is fit over the O-ring  114  when in the groove  112  the O-ring is partially deformed to form an elliptical cross-section shape. The end cap assembly  26  is essentially as described hereinabove. The duct  110  can be truncated (compared to the duct  14  described hereinabove) so that the second end  44  is the terminating end of the duct  110 . In this configuration at least a portion of the duct  110  proximate to the second end  44 , and possibly the beveled section  40  are bonded to a conventional duct  116 , such as, but not limited to, rubber, solid metal, metal mesh, PVC, or the like. The second end  44  can be bonded to the duct  116  using any of various techniques know to those skilled in the art. In this manner, conventional ducting can be adapted for connection to tubes  4 ,  6  by being bonded to the duct  110  of the present invention. The groove  112  can be elongated to accommodate more than one O-ring  114 , should several be necessary.  
         [0032]     The present invention contemplates optimally needing only about 6-8% squeeze (particularly when using the Rishon® duct material from RCF Technologies, Inc.) to form a suitable seal, in comparison to existing sealing apparatus, which require some 18-20% squeeze. Should the tubes  4 ,  6  be subject to stress which attempts to pull them apart, the beads  8 ,  10  are abutted by the flange  34 ,  48  portion of the duct  14  and are prevented from being pulled apart. Similarly, the seal between the duct  14  and tube  3 ,  4  is maintained. Since the duct  14  has an inherent amount of flexion, should either or both of the tubes  4 ,  6  be turned, twisted, bent, vibrated, pulled, or the like, the duct  14  can accommodate such movement while maintaining the seal. The split ring  22  reduces the possibility of counterclockwise rotation of the compression ring during stress. The split ring notch  70  mates with the lip  74  of the compression ring to form a tight fit. The end cap assembly  26  eliminates the need for tightening a worm gear type clamp, which is subject to manual errors of insufficient tightening or overtightening or mis-positioning, all of which can lead to leakage. The reinforcing band, while optional, helps to restrict the duct  14  against undue expansion under stress.  
         [0033]     In another aspect the present invention provides a novel duct useful for joining two tubes, the duct being as shown and described above.  
         [0034]     Although only a few exemplary embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the following claims.  
         [0035]     It should further be noted that any patents, applications and publications referred to herein are incorporated by reference in their entirety.