Reinforced thermoplastic pipe manufacture

Abstract

A fiber reinforced thermoplastic pipe member is obtained by a novel continuous process in which the reinforcement fibers are wrapped about the outer pipe surface in an unbonded condition while the pipe member continuously moves in a linear direction and which is followed by sufficient heating of the moving fiber wrapped pipe member to cause thermal bonding between the applied fibers and the pipe member. Automated apparatus for carrying out the continuous process is also disclosed.

What I claim as new and desire to secure by Letters Patent of the United States is:  
     
         1 . A method for reinforcement of a pipe length with inner and outer surfaces and formed with a solid thermoplastic organic polymer which comprises: 
 (a) continuously moving the pipe length in a linear direction,    (b) wrapping a plurality of continuous juxtapositioned reinforcement fibers formed with a material composition selected from the group consisting of ceramics, metals, carbon and organic polymers while in an unbonded condition about the outer surface of said moving pipe length in a predetermined spatial direction, and    (c) heating the fiber wrapped pipe length sufficiently to cause thermal bonding between the reinforcement fibers and the pipe length while said pipe length continues to move in the same linear direction.    
     
     
         2 . The method of  claim 1  wherein the thermal bonding includes radial expansion of the moving pipe length.  
     
     
         3 . The method of  claim 1  wherein the thermal bonding includes melting of the pipe outer surface.  
     
     
         4 . The method of  claim 1  wherein the reinforcement fibers are provided in a matrix formed with a solid thermoplastic organic polmer.  
     
     
         5 . The method of  claim 4  wherein the thermal bonding includes melting of the fiber matrix.  
     
     
         6 . The method of  claim 1  wherein the thermal bonding includes radial expansion of the moving pipe length and melting of the pipe outer surface.  
     
     
         7 . The method of  claim 4  wherein the thermal bonding includes radial expansion of the moving pipe length while being accompanied by melting of the outer pipe surface as well as melting of the reinforcement fiber matrix.  
     
     
         8 . A method for reinforcement of a plurality of identical pipe lengths joined together at the ends and each formed of the same solid thermoplastic polymer with inner and outer surfaces which comprises: 
 (a) continuously moving the joined pipe lengths in a linear direction,    (b) wrapping a plurality of continuous juxtapositioned reinforcement fibers formed with a material composition selected from the group consisting of ceramics, metals, carbon and organic polymers while in an unbonded condition about the outer surface of each moving joined pipe length in a predetermined spatial direction, and    (c) heating the fiber wrapped pipe lengths sufficiently to cause thermal bonding between the reinforcement fibers and the pipe lengths while said joined pipe lengths continue to move in the same linear direction.    
     
     
         9 . The method of  claim 8  wherein the thermal bonding includes radial expansion of the moving pipe lengths.  
     
     
         10 . The method of  claim 8  wherein the thermal bonding includes melting of the pipe outer surfaces.  
     
     
         11 . The method of  claim 8  wherein the reinforcement fibers are provided in a matrix formed with a solid thermoplastic organic polymer.  
     
     
         12 . The method of  claim 11  wherein the thermal bonding includes melting of the fiber matrix.  
     
     
         13 . The method of  claim 8  wherein the thermal bonding includes radial expansion of the moving pipe lengths and melting of the outer pipe surfaces.  
     
     
         14 . The method of  claim 11  wherein the thermal bonding includes radial expansion of the moving pipe lengths while being accompanied by melting of the outer pipe surfaces as well as melting of the reinforcement fiber matrix.