Composite Sucker Rod Assemblies

Abstract

Sucker rod assemblies are provided. A sucker rod assembly includes one or more continuous fiber reinforced thermoplastic rods. Each rod has a core comprising a plurality of generally unidirectionally oriented continuous fibers embedded in a thermoplastic resin. A sucker rod assembly further includes a first end fitting and a second end fitting, at least one of which is connected to the plurality of continuous fiber reinforced thermoplastic rods. Each rod has an ultimate tensile strength of between approximately 280,000 pounds per square inch and approximately 370,000 pounds per square inch, and the continuous fibers have a ratio of ultimate tensile strength to mass per unit length of greater than about 1,000 Megapascals per gram per meter. The continuous fibers constitute from about 25 wt. % to about 80 wt. % of each rod, and the thermoplastic resin constitutes from about 20 wt. % to about 75 wt. % of each rod.

What is claimed is: 
     
         1 . A sucker rod assembly, the sucker rod assembly comprising:
 a plurality of continuous fiber reinforced thermoplastic rods arranged in a stranded bundle, each of the plurality of continuous fiber reinforced thermoplastic rods having a core comprising a plurality of generally unidirectionally oriented continuous fibers embedded in a thermoplastic resin; and   a first end fitting and a second end fitting, at least one of the first and second end fittings connected to the plurality of continuous fiber reinforced thermoplastic rods,   wherein each of the plurality of rods has an ultimate tensile strength of between approximately 280,000 pounds per square inch and approximately 370,000 pounds per square inch, wherein the continuous fibers have a ratio of ultimate tensile strength to mass per unit length of greater than about 1,000 Megapascals per gram per meter, and wherein the continuous fibers constitute from about 25 wt. % to about 80 wt. % of each of the plurality of rods and the thermoplastic resin constitutes from about 20 wt. % to about 75 wt. % of each of the plurality of rods.   
     
     
         2 . The sucker rod assembly of  claim 1 , wherein each of the plurality of rods has an ultimate tensile strength of between approximately 320,000 pounds per square inch and approximately 370,000 pounds per square inch. 
     
     
         3 . The sucker rod assembly of  claim 1 , wherein the continuous fibers have a ratio of ultimate tensile strength to mass per unit length of from about 5,000 to about 20,000 Megapascals per gram per meter. 
     
     
         4 . The sucker rod assembly of  claim 1 , wherein the continuous fibers are carbon fibers. 
     
     
         5 . The sucker rod assembly of  claim 1 , wherein the thermoplastic resin includes a polyarylene sulfide. 
     
     
         6 . The sucker rod assembly of  claim 5 , wherein the polyarylene sulfide is polyphenylene sulfide. 
     
     
         7 . The sucker rod assembly of  claim 1 , wherein the continuous fibers constitute from about 30 wt. % to about 75 wt. % of each of the plurality of rods. 
     
     
         8 . The sucker rod assembly of  claim 1 , wherein the core of each of the plurality of rods has a void fraction of about 3% or less. 
     
     
         9 . The sucker rod assembly of  claim 1 , wherein each of the plurality of rods has a minimum flexural modulus of about 10 Gigapascals. 
     
     
         10 . The sucker rod assembly of  claim 1 , wherein each of the plurality of rods has a minimum tensile modulus of elasticity of about 50 Gigapascals. 
     
     
         11 . The sucker rod assembly of  claim 1 , wherein each of the plurality of rods has a bend radius of from about 0.5 to about 10 centimeters. 
     
     
         12 . The sucker rod assembly of  claim 1 , further comprising a capping layer surrounding the core of each of the plurality of rods. 
     
     
         13 . The sucker rod assembly of  claim 12 , wherein the capping layer includes polyetherether ketone. 
     
     
         14 . The sucker rod assembly of  claim 12 , wherein the capping layer is free from fibers. 
     
     
         15 . A sucker rod assembly, the sucker rod assembly comprising:
 a single monolithic continuous fiber reinforced thermoplastic rod, the continuous fiber reinforced thermoplastic rod having a core and a capping layer surrounding the core, the core comprising a plurality of generally unidirectionally oriented continuous fibers embedded in a thermoplastic resin, wherein the fibers are carbon fibers and the thermoplastic resin includes a polyarylene sulfide, the capping layer including polyetherether ketone and free from fibers; and   a first end fitting and a second end fitting, at least one of the first and second end fittings connected to the continuous fiber reinforced thermoplastic rod,   wherein the continuous fiber reinforced thermoplastic rod has an ultimate tensile strength of between approximately 280,000 pounds per square inch and approximately 370,000 pounds per square inch, and wherein the continuous fibers constitute from about 25 wt. % to about 80 wt. % of the rod and the thermoplastic resin constitutes from about 20 wt. % to about 75 wt. % of the rod.   
     
     
         16 . The sucker rod assembly of  claim 15 , wherein the continuous fiber reinforced thermoplastic rod has an ultimate tensile strength of between approximately 320,000 pounds per square inch and approximately 370,000 pounds per square inch. 
     
     
         17 . The sucker rod assembly of  claim 15 , wherein the polyarylene sulfide is polyphenylene sulfide. 
     
     
         18 . The sucker rod assembly of  claim 15 , wherein the continuous fibers constitute from about 30 wt. % to about 75 wt. % of the rod. 
     
     
         19 . The sucker rod assembly of  claim 15 , wherein the core of the rod has a void fraction of about 3% or less. 
     
     
         20 . The sucker rod assembly of  claim 15 , wherein the rod has a minimum flexural modulus of about 10 Gigapascals. 
     
     
         21 . The sucker rod assembly of  claim 15 , wherein the rod has a minimum tensile modulus of elasticity of about 50 Gigapascals. 
     
     
         22 . The sucker rod assembly of  claim 15 , wherein the rod has a bend radius of from about 0.5 to about 10 centimeters.