Abstract:
A hose for transport of conditioned air between a ground-based heating-ventilating unit and an internal ventilation system of an aircraft comprises at least one hose segment. The hose segment has an end provided with a fastener interconnectable with a fastener on an end of an adjacent hose segment. The hose segment also has an interior insulation layer sealed to inhibit migration of moisture between the insulation layer and the interior of the hose.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application is a continuation in part of U.S. patent application Ser. No. 09/248,431 filed on Feb. 11, 1999, which claims the benefit of U.S. Provisional Application No. 60/074,623, filed on Feb. 13, 1998. 
     
    
     
       BACKGROUND OF INFORMATION  
         [0002]    1. Field of the Invention  
           [0003]    The invention relates generally to interconnectable, insulated flexible ventilation ducts. More specifically, the invention relates to air ducts for transporting conditioned air.  
           [0004]    2. Related Art  
           [0005]    During the time an aircraft is located adjacent to an airport gate, conditioned air can be transported to the aircraft from a ground-based heating or air conditioning system. This is done through the use of insulated flexible duct that connects the heating or air conditioning unit of the airport with the internal ventilation system of the aircraft.  
           [0006]    These ducts have been manufactured with various materials and in varying lengths to accommodate different types of aircraft. They are typically formed of several segments connected together through releasable connections. Depending upon the type of the aircraft being serviced, it is necessary to add or delete segments of the duct to establish a suitable and appropriate connection of the aircraft ventilation system with the ground-based unit. The releasable connections can comprise zippers or hook and loop fasteners, such as Velcro®. An example of a duct assembly employing hook and loop fasteners to interconnect adjacent segments of the ducts is shown in U.S. Pat. No. 5,368,341 (Larson), issued Nov. 29, 1994.  
           [0007]    It is known to use insulation to retard heat transfer between the interior of the duct and the exterior, since the air is typically conditioned, i.e., either heated or cooled and humidified or dehumidified to a comfortable level. A problem with known insulated ducts is their propensity for the insulation layer to absorb moisture, particularly in warm, humid climates. Passing air picks up moisture in the insulation layer, thus altering its pre-conditioned state. Moreover, heavily moisture-laden insulation diminishes the durability of the duct and renders it more difficult to maneuver. This often happens particularly where open cell foam is used as the insulating layer, or where the insulating layer is exposed to the exterior, such as through a stitched seam or through abrasions in the exterior sheath. The need exists for more durable ventilation duct, given the harsh rigors of its typical use on airport ramps, along with a need for a greater degree of protection for the insulation and for the connections.  
         SUMMARY OF INVENTION  
         [0008]    This invention relates to a hose for delivery of conditioned air between a ground-based heating-ventilating unit and an internal ventilation system of an aircraft. The hose has at least one hose segment having an interior layer of insulation. The insulation has a surface sealed against migration of moisture into or out of the insulation layer. Thus, migration of moisture into the interior of the hose through the insulation layer is inhibited.  
           [0009]    In one aspect, the surface is sealed by a sealing agent. Preferably the sealing agent is polyurethane which can be sprayed on the interior surface. In another aspect, the sealing agent is a film, preferably polyolefin.  
           [0010]    The insulation itself can comprise an open cell foam. And may have two surfaces where one or both are sealed. One of the surfaces would be exposed to the interior of the hose where the conditioned air passes.  
           [0011]    In another aspect, the invention is directed a combination of at least two hose segments. Each hose segment has an end with a fastener connectable with an adjacent fastener on an adjacent hose segment. At least one protective flap is preferably located adjacent the fastener on one hose segment and is preferably adapted to cover the fastener and an interconnected fastener when a pair of hose segments are connected to each other. A sealed insulation layer surrounds the interior of each hose segment.  
           [0012]    Other objects, features, and advantages of the invention will be apparent from the ensuing description in conjunction with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0013]    [0013]FIG. 1 is a perspective view showing the air duct according to the invention shown extending between an airport terminal ventilation system and an aircraft.  
         [0014]    [0014]FIG. 2 is a fragmentary perspective view of interconnected segments of the duct of FIG. 1.  
         [0015]    [0015]FIG. 3 is an exploded perspective view showing adjacent segments of the duct of FIG. 1 with arrows showing the interconnection of the ends of the adjacent segments.  
         [0016]    [0016]FIG. 4 is a perspective view showing a first stage of interconnection between the ends of the two adjacent segments of FIG. 3.  
         [0017]    [0017]FIG. 5 is a perspective view showing a nearly complete interconnection between the ends of the adjacent duct segments of FIG. 4. 
     
    
     DETAILED DESCRIPTION  
       [0018]    Turning to the drawings and to FIG. 1 in particular, a air duct  10  for transporting conditioned to an aircraft  12  is shown comprising several interconnected segments  14 , the ends of which are serially joined together by closure connections  16 . It is understood that the number of segments actually needed will vary depending on a number of factors such as the size of the aircraft and the proximity of the aircraft to the gate. Indeed, if the segment is long enough, or the distance between the aircraft and the gate is short enough, only a single segment will be needed. For this invention, it is assumed that at least one segment will be needed. The size of each segment is limited by its manual transportability and the ease with which it can be stored, unstored and connected to ventilation systems and/or adjacent segments. When the duct segment or segments  14  are in place, conditioned air can be carried from a ventilating system  18  typically located within an airport to an internal ventilating system (not shown) of the aircraft  12  on a ground surface  20  before the aircraft  12  is ready for takeoff. Interconnection of the internal ventilation system of the aircraft  12  to the ventilating system  18  on the ground  20  allows the internal ventilation system of the aircraft  12  to cease generation and delivery of conditioned air to any occupants of the aircraft  12  and permits the aircraft engines to be shut down. Rather, the conditioned air is supplied from the ventilating system  18  of the airport.  
         [0019]    Looking now at FIGS. 2 and 3, each duct segment  14  has an exterior sheath preferably manufactured from a vinyl material, such as coated nylon, which affords optimum strength and flexibility in all types of weather conditions and temperatures. Each segment  14  is formed from a single rectangular length of the duct material joined along opposing longitudinal sides  22  thereof by a longitudinal seam  24 . The seam  24  is preferably welded to provide maximum tear-resistance and prevent the escape of any conditioned air carried within the duct  10 , and a longitudinal strip  25  of similar material can be welded over the longitudinal seam  24  to provide additional protection. Of course, with the protective longitudinal strip  25 , the longitudinal seam can be formed in other ways, such as by stitching. An insulation layer  27  is disposed interior to the duct adjacent to the exterior sheath primarily to retard heat transfer between conditioned air passing through the duct and the exterior atmosphere. The insulation layer  27  may be formed of closed cell foam to minimize water absorption. More often, however, open cell foam has been found to be more cost-effective. The duct  10  is flexible, especially radially, to permit deformation of the duct  10  so as to be flat on the ground surface  20 . Thus, ground vehicles can be driven over the duct  10  without permanent damage to the duct. Moreover, the duct itself can be rolled up for storage.  
         [0020]    Each segment  14  has a first end  26  and a second end  28 . The first and second ends  26  and  28  each carry closure connections  16  which enable a second end  28  of an adjacent segment  14  to be interconnected to the first end  26  of another segment  14  of the duct  10 , or, alternatively, either to an airport ventilation system or to an aircraft. Closure connections  16  include any type of fastener that would secure the connection against axial separation, such as zippers, snaps, hook and loop, and the like.  
         [0021]    In a preferred embodiment, the connections  16  on the first end  26  of each segment  14  includes a first portion  30  of a zipper used for interconnecting adjacent segments  14  of the duct  10  which preferably extends substantially around the circumference of the first end  26 . A first portion  32  of a hook and loop fastener, such as Velcro®, is located adjacent to the first portion  30  of the zipper and preferably axially inwardly thereof.  
         [0022]    The second end  28  of each segment  14  includes a second portion  34  of the zipper which is adapted to interconnect with the first portion  30  of the zipper on the first end  26  of the segment  14 . The second end  28  of the segment  14  is also provided with several flexible flaps  36  extending axially outwardly of the second portion  34  of the zipper.  
         [0023]    Each flap  36  includes an interior surface  38  provided with a transversely-extending second portion  40  of the hook and loop fastener that is adapted to removably engage the first portion  32  of the hook and loop fastener on the first end  26  of an adjacent segment  14 .  
         [0024]    Each flap  36  also includes a first end  42  and a second end  44 . The first end  42  of each flap  36  has a first portion  46  of a hook and loop fastener provided on the interior surface  38  of the flap  36 . The second end  44  of each flap  36  is provided with a second portion of a hook and loop fastener on an exterior surface  50  of the flap  36 .  
         [0025]    The flaps  36  are preferably formed as circumferential extensions of the second end  28  of the segment  14  whereby a first end  42  of one flap  36  is adapted to overlap a second end  44  of an adjacent flap  36 . The first portion  46  of the hook and loop fastener on the first end  42  of one flap thereby overlaps and engages the second portion  48  of the hook and loop fastener located on the second end  44  of an adjacent flap  36  as shown in the drawings.  
         [0026]    Although three flaps  36  are shown in the drawings, it will be understood that additional or fewer flaps  36  can be provided to the second end  28  of the segment  14  without departing from the scope of this invention.  
         [0027]    In the illustrated assembly, the first end  26  of one segment  14  is brought adjacent to the second end  28  of an adjacent segment  14  as shown in FIG. 4. The first portion  30  of the zipper on the first end  26  of one segment  14  is engaged with the second portion  34  of the zipper on the second end  28  of the other segment  14 . The zipper is then circumferentially traversed so that the first and second portions  30  and  34  thereof are interengaged. Thus, the primary function of the zipper, and specifically the first and second portions  30  and  34  thereof, is to securely interconnect the first and second ends  26  and  28  of adjacent duct segments  14 .  
         [0028]    The flaps  36  located on the second end  28  of the segment  14  have the primary purpose of providing a protective cover to prevent environmental elements from damaging the first and second portions  30  and  34  of the zipper. Once the first and second portions  30  and  34  of the zipper on adjacent segments  14  are interengaged, the flaps  36  on the second end  28  on one segment  14  can be folded toward the first end  26  on the adjacent segment  14  so that the second portion  40  of the hook and loop fastener located on the interior surface  38  of each flap  36  overlaps and engages the first portion  32  of the hook and loop fastener located on the first end  26  of the adjacent segment  14 . The flaps  36  thereby enclose the first and second portions  30  and  34  of the zipper.  
         [0029]    The first portion  46  of the hook and loop fastener located on the first end  42  of each flap  36  can also be engaged with the second portion  48  of the hook and loop fastener located on the second end  44  of the adjacent flap  36  so that each of the flaps  36  are engaged with a successive and a preceding flap  36  as well as with the first end  26  of the adjacent segment  14 . Thus, the interengagement of each of the successive and preceding flaps  36  in connection with the engagement of each flap  36  with the first end  26  of the adjacent segment  14  forms an impermeable enclosure for the first and second portions  30  and  34  of the zipper.  
         [0030]    It will be understood that the seam  24  is preferably welded whereby the material on one longitudinal side  22  of the rectangular piece of duct material is bonded with the material on the other longitudinal side  22  of the piece. It has been found that the welded seam has greater strength than conventional stitch seams as well as not being subject to unraveling due to abrasion, such as when the duct  10  is dragged across the ground surface  20  during use. More importantly, the welded seam more effectively inhibits penetration of moisture from the exterior of the sheath. This especially so when the longitudinal strip  25  is welded over the seam, providing an additional layer of protection.  
         [0031]    It has also been found that coupling the first and second ends  26  and  28  of adjacent segments  14  of the duct  10  with a zipper eliminates decoupling of the adjacent segments  14  during use. Further, covering the first and second portions  30  and  34  of the zipper with the flaps  36  keeps the first and second portions  30  and  34  of the zipper clean and easy to operate even in inclement weather conditions. Engagement of the flaps  36  with the first end  26  of an adjacent segment  14  as well as with immediately preceding and succeeding flaps  36  provides a secure protective cover to the first and second portions  30  and  34  of the zipper. Although a zipper is thought to more securely attach adjacent segments, it will be understood that a zipper is not a requirement for this invention.  
         [0032]    The foam insulation is preferably bonded to the outer ply of waterproof fabric with a well-known bonding agent such as a hot melt adhesive. Thus, the duct  10  is lightweight while preventing conditioned air from escaping from within the duct  10  or between the interconnection between the first and second ends  26  and  28  of adjoining segments  14 . The insulation is further sealed against moisture invasion by a polyurethane spray on the interior surface of the insulation layer after the insulation is bonded to the outer ply. Thus, migration of moisture between the insulation layer and conditioned air passing through the duct is inhibited. It will be understood that any type of conventional sealant can be applied to the insulation layer. Moreover, the application can occur prior to the adhesion of the foam layer to the outer ply, in which case, the sealant can be applied to one or both sides of the insulation layer. For example, a thin sheet of sealing film can be calendared to one or both surfaces of the insulation layer prior to adhering the insulation layer to the outer ply. Polyolefin has been found to be an effective sealing film.  
         [0033]    While particular embodiments of the invention have been shown, it will be understood, of course, that the invention is not limited thereto since modifications may be made by those skilled in the art, particularly in light of the foregoing teachings. Reasonable variation and modification are possible within the scope of the foregoing disclosure of the invention without departing from the spirit of the invention.