Internal Lining for Pipe Surfaces and Method of Lining Pipes

Abstract

A pipe lining having at least two material layers, a first elastomeric layer spray applied directly to the inside of a pipe which acts as a hydrophobic, ductile membrane, and a second rigid layer is spray applied to the first layer prior to complete curing of the first layer. One or more additional layers may be applied to the second layer to provide additional abrasion, erosion or chemical resistance to the second layer. An intermediate reinforcing layer may be disposed between the first and second layers. The first layer cures into a closed cell elastomeric foam, such that stress and other forces are not passed from the pipe to the rigid second layer.

I claim: 
     
         1 . A combination pipe and pipe liner, the pipe liner adhered to the inside of the pipe, the liner comprising a first layer and a second layer;
 said first layer formed of a curable polymeric material applied to said pipe and allowed to cure such that said first layer is an elastomeric foam layer, and   said second layer formed of a curable thermosetting polymeric material applied to said first layer and allowed to cure such that said second layer is a rigid layer bonded to said first layer.   
     
     
         2 . The combination of  claim 1 , wherein said first layer possesses a modulus of elasticity of approximately 100 to 10,000 psi, and wherein said second layer possesses a modulus of elasticity of approximately 250,000 to 750,000 psi. 
     
     
         3 . The combination of  claim 1 , wherein said first layer possesses a Poison's ratio not greater than approximately 0.25, and wherein said second layer possesses a Poisson's ratio not less than approximately 3.0. 
     
     
         4 . The combination of  claim 2 , wherein said first layer possesses a Poison's ratio not greater than approximately 0.25, and wherein said second layer possesses a Poisson's ratio not less than approximately 3.0. 
     
     
         5 . The combination of  claim 1 , wherein said first layer possesses elongation of approximately 500 to 1500%, and wherein said second layer possesses elongation of less than approximately 25%. 
     
     
         6 . The combination of  claim 2 , wherein said first layer possesses elongation of approximately 500 to 1500%, and wherein said second layer possesses elongation of approximately 1 to 25%. 
     
     
         7 . The combination of  claim 3 , wherein said first layer possesses elongation of approximately 500 to 1500%, and wherein said second layer possesses elongation of approximately 1 to 25%. 
     
     
         8 . The combination of  claim 4 , wherein said first layer possesses elongation of approximately 500 to 1500%, and wherein said second layer possesses elongation of approximately 1 to 25%. 
     
     
         9 . The combination of  claim 1 , wherein said first layer possesses a gel rate approximately 2-300 seconds and becomes tack-free in approximately 60-600 seconds, and wherein said second layer possesses a snap cure rate of approximately 3-300 seconds and a full cure rate of 1-24 hours. 
     
     
         10 . The combination of  claim 1 , wherein said first layer is formed of a hydrophobic/moisture tolerant polymeric material, characterized in that said polymeric material does not absorb or react to moisture or fluids prior to curing and is liquid impermeable after curing. 
     
     
         11 . The combination of  claim 1 , further comprising a third layer, said third layer formed of a polymeric material applied to said second layer and allowed to cure. 
     
     
         12 . The combination of  claim 1 , wherein said second layer polymeric material is applied to said first layer polymeric material prior to said first layer polymeric material fully curing into said elastomeric foam layer. 
     
     
         13 . The combination of  claim 1 , further comprising an intermediate reinforcing layer between said first layer and said second layer. 
     
     
         14 . The combination of  claim 13 , wherein said intermediate reinforcing layer comprising a helically wound filament. 
     
     
         15 . The combination of  claim 14 , wherein said helically wound filament is resin-impregnated and said helically wound filament is chosen from the group of filaments consisting of carbon fiber, E-glass and Aramid fiber. 
     
     
         16 . The combination of  claim 14 , wherein the majority of said helically wound filament is embedded within said second layer. 
     
     
         17 . A pipe liner comprising a tubular elastomeric polymeric foam first layer and a tubular rigid polymeric second layer, said second layer bonded internally to said first layer. 
     
     
         18 . The pipe liner of  claim 17 , wherein said first layer possesses a modulus of elasticity of approximately 100 to 10,000 psi, and wherein said second layer possesses a modulus of elasticity of approximately 250,000 to 750,000 psi. 
     
     
         19 . The liner of  claim 17 , wherein said first layer possesses a Poison's ratio not greater than approximately 0.25, and wherein said second layer possesses a Poisson's ratio not less than approximately 3.0. 
     
     
         20 . The liner of  claim 17 , wherein said first layer possesses elongation of approximately 500 to 1500%, and wherein said second layer possesses elongation of approximately 1 to 25%. 
     
     
         21 . The liner of  claim 17 , wherein said first layer possesses a gel rate of approximately 2-300 seconds and becomes tack-free in approximately 60-600 seconds, and wherein said second layer possesses a snap cure rate of approximately 3-300 seconds and a full cure rate of 1-24 hours. 
     
     
         22 . The liner of claim  127 , wherein said first layer is formed of a hydrophobic/moisture tolerant polymeric material, characterized in that said polymeric material does not absorb or react to moisture or fluids prior to curing and is liquid impermeable after curing. 
     
     
         23 . The liner of  claim 17 , further comprising a third layer, said third layer formed of a polymeric material applied to said second layer and allowed to cure. 
     
     
         24 . The liner of  claim 17 , wherein said second layer polymeric material is applied to said first layer polymeric material prior to said first layer polymeric material fully curing into said elastomeric foam layer. 
     
     
         25 . The combination of  claim 17 , further comprising an intermediate reinforcing layer between said first layer and said second layer. 
     
     
         26 . The combination of  claim 25 , wherein said intermediate reinforcing layer comprising a helically wound filament. 
     
     
         27 . The combination of  claim 26 , wherein said helically wound filament is resin-impregnated and said helically wound filament is chosen from the group of filaments consisting of carbon fiber, E-glass and Aramid fiber. 
     
     
         28 . The combination of  claim 26 , wherein the majority of said helically wound filament is embedded within said second layer. 
     
     
         29 . A method of lining a pipe comprising the steps of:
 applying a first curable polymeric material to the inside of said pipe and allowing said polymeric material to cure to form an elastomeric foam first layer;   applying a second curable thermosetting polymeric material to the inside of said elastomeric first layer to from a rigid second layer bonded to said first layer;   said second curable thermosetting polymeric material being applied to said first curable polymeric material prior to said first curable polymeric material fully curing to form said elastomeric foam first layer.   
     
     
         30 . The method of  claim 29 , further comprising the step of choosing said first curable polymeric material such that said elastomeric foam first layer possesses a modulus of elasticity of approximately 100 to 10,000 psi, and choosing said second curable thermosetting polymeric material such that said rigid second layer possesses a modulus of elasticity of approximately 250,000 to 750,000 psi. 
     
     
         31 . The method of  claim 29 , further comprising the step of choosing said first curable polymeric material such that said elastomeric foam first layer possesses a Poison's ratio not greater than approximately 0.25, and wherein said second layer possesses a Poisson's ratio not less than approximately 3.0. 
     
     
         32 . The method of  claim 29 , further comprising the step of choosing said first curable polymeric material such that said elastomeric foam first layer possesses elongation of approximately 500 to 1500%, and choosing said second curable thermosetting polymeric material such that said rigid second layer possesses elongation of approximately 1 to 25%. 
     
     
         33 . The method of  claim 29 , further comprising the step of choosing said first curable polymeric material such that said first curable polymeric material begins gelling in approximately 2-300 seconds and becomes tack-free in approximately 60-600 seconds, and choosing said second curable thermosetting polymeric material such that said second curable thermosetting polymeric material has a snap cure rate of approximately 3-300 seconds and a full cure rate of 1-24 hours. 
     
     
         34 . The method of  claim 29 , further comprising the step of choosing said first curable polymeric material such that said first curable polymeric material is formed of a hydrophobic/moisture tolerant polymeric material, characterized in that said first curable polymeric material does not absorb or react to moisture or fluids prior to curing and is liquid impermeable after curing. 
     
     
         35 . The method of  claim 29 , further comprising the step of applying an intermediate reinforcing layer onto said first layer prior to applying said second layer. 
     
     
         36 . The method of  claim 35 , wherein said intermediate reinforcing layer is composed of filaments and said step of applying said intermediate reinforcing layer comprises helically winding said filaments onto said first layer prior to full cure of said first layer. 
     
     
         37 . The method of  claim 36 , wherein said step of applying said intermediate reinforcing layer comprises allowing said first layer to partially cure sufficiently such that said filaments adhere to the surface of said first layer, and further such that the majority of said filaments become embedded in said second layer when said second layer is applied. 
     
     
         38 . The method of  claim 37 , wherein said intermediate reinforcing layer comprises UV-curable, resin-impregnated, helically wound filaments, and further comprising the step of exposing said filaments to UV radiation to cure said filaments upon applying said filament to said first layer.