Clad duct

Abstract

A clad duct comprising an outer sheet of thermoplastic material and an inner duct of rigid foam is disclosed. The outer sheet of thermoplastic material is bonded to the inner duct. The outer sheet has a first edge and a second edge and a seal is provided to seal the first edge and the second edge.

I claim: 
     
         1 . A clad duct comprising
 an outer cladding layer composed of a thermoplastic material having a first edge and a second edge,   an inner lining composed of an insulative foam board,   said outer skin and said insulative foam board being bonded together by an adhesive, and   a seal that seals said first and second edges of said outer cladding layer.   
     
     
         2 . The clad duct claimed in  claim 1  wherein said outer cladding layer is composed of a PVC based material. 
     
     
         3 . The clad duct claimed in  claim 2  wherein said PVC based material is further composed of an additive that increases the resistance of said outer cladding layer to degradation by ultraviolet radiation. 
     
     
         4 . The clad duct claimed in  claim 1  wherein said insulative foam board is a rigid foam. 
     
     
         5 . The clad duct claimed in  claim 4  wherein said insulative foam board is phenolic based foam. 
     
     
         6 . The clad duct claimed in  claim 5  wherein said insulative foam board is faced on one side with a facing material. 
     
     
         7 . The clad duct claimed in  claim 6  wherein said insulative board is faced on both sides with a facing material. 
     
     
         8 . The clad duct claimed in  claim 1  wherein said adhesive is a polyurethane based adhesive system. 
     
     
         9 . The clad duct claimed in  claim 1  wherein said seal is a right angle strip adhesively bonded to the outside of said outer cladding layer so that it spans said first and second edges thereof. 
     
     
         10 . The clad duct claimed in  claim 1  wherein said seal comprises a weld joining said first and second edges of said cladding layer. 
     
     
         11 . The clad duct claimed in  claim 10  wherein said weld is formed of a material having substantially the same composition as said cladding layer. 
     
     
         12 . A clad duct comprising
 an outer cladding layer composed of a sheet of PVC based thermoplastic material having a first edge and a second edge,   an inner lining composed of an insulative, phenolic based, rigid foam board, and   a seal that seals said first and second edges of said outer cladding layer,   wherein said outer layer and said inner lining are adhesively bonded to each other by a polyurethane based adhesive.   
     
     
         13 . The clad duct claimed in  claim 12  wherein said insulative foam board is faced on one side with a facing material. 
     
     
         14 . The clad duct claimed in  claim 12  wherein said insulative board is faced on both sides with a facing material. 
     
     
         15 . The clad duct claimed in  claim 12  wherein said seal is a right angle strip adhesively bonded to the outside of said outer cladding layer so that it spans said first and second edges thereof. 
     
     
         16 . The clad duct claimed in  claim 15  wherein said right angle strip is formed of a material having substantially the same composition as said cladding layer 
     
     
         17 . The clad duct claimed in  claim 12  wherein said seal comprises a weld joining said first and second edges of said cladding layer. 
     
     
         18 . The clad duct claimed in  claim 17  wherein said weld is formed of a material having substantially the same composition as said cladding layer. 
     
     
         19 . A clad duct comprising
 an outer cladding layer composed of a sheet of PVC based thermoplastic material having a first edge and a second edge,   an inner lining composed of an insulative, phenolic based, rigid foam board that is faced on at least one side with a facing material, and   a seal that seals said first and second edges of said outer cladding layer,   wherein said outer layer and said inner lining are adhesively bonded to each other by a polyurethane based adhesive.