High-pressure fiber reinforced composite pipe joint

A pipe joint comprising:

• a fiber reinforced composite pipe having an external pipe joint moiety on one end;
• a groove extending helically along the length of the external pipe joint moiety;
• a coupling having an internal pipe joint moiety having an included half angle the same as an included half angle on the external pipe joint moiety;
• a groove extending helically along the length of the internal pipe joint moiety having the same pitch as the groove in the external pipe joint moiety;
• and
• a key member extending helically a plurality of turns along both grooves for locking the external and internal pipe joint moieties together, the key member having sufficient ductility for plastically deforming in shear and redistributing longitudinal loads along the length of the pipe joint.

A pipe joint comprising:

• a fiber reinforced composite pipe having an external taper on one end;
• a groove extending helically along the length of the external taper;
• a coupling having an internal taper having an included half angle the same as an included half angle on the external taper;
• a groove extending helically along the length of the internal taper having the same pitch as the groove in the external taper;
• a ductile key member extending helically along both grooves for locking the external and internal tapers together;
• a first surface outside the pipe adjacent at least one end of the key member;
• a second surface inside the coupling facing the first surface;
• and
• an elastic sealant between the facing surfaces adhered to both facing surfaces for sealing the joint.

A pipe joint comprising:

• a fiber reinforced composite pipe having an external pipe joint moiety on one end;
• a coupling having an internal pipe joint moiety matching the external pipe joint moiety;
• means for locking the external and internal pipe joint moieties together in a longitudinal direction;
• and
• means for sealing the joint spaced apart from the means for locking the joint moieties together comprising:
• a first surface outside the pipe,
• a second surface inside the coupling facing the first surface,
• a pair of spaced apart circumferential elastomeric seals between the first and second surfaces, and
• a sealant between the elastomeric seals and adhered to both surfaces, the sealant being sufficiently elastic for accommodating the maximum longitudinal shear strain of the pipe joint.

A pipe joint comprising:

• a fiber reinforced composite pipe having an external taper on one end;
• a groove extending helically along the length of the external taper;
• a coupling having an internal taper having an included half angle the same as an internal half angle on the external taper, wherein the hoop stiffness of the coupling adjacent to the internal taper is at least twice as large as the hoop stiffness of the pipe adjacent to the external taper;
• a groove extending helically along the length of the internal taper having the same pitch as the groove in the external taper;
• and
• a ductile key member extending helically along both grooves for locking the external and internal tapers together.

A pipe joint comprising:

• a fiber reinforced composite pipe having an external taper on one end;
• a half round groove extending helically along the length of the external taper;
• a fiber reinforced composite coupling having an internal taper having an included half angle the same as an included half angle on the external taper;
• a half round groove extending helically along the length of the internal taper having the same pitch as the groove in the external taper;
• and
• a round ductile key member extending helically a plurality of turns along both grooves for locking the external and internal tapers together, the key member having a shear strength of up to about one half the shear strength of the pipe and coupling adjacent to the grooves.

A pipe joint comprising:

• a glass fiber reinforced composite pipe having an external taper on one end with an included half angle in the range of from two to four degrees;
• a half round groove extending helically a plurality of turns along the length of the external taper;
• a fiber reinforced composite coupling having an internal taper having an included half angle the same as the half angle on the external taper, at least a portion of the coupling being formed of a sufficient amount of material having a higher modulus of elasticity than glass to provide a hoop stiffness greater than the hoop stiffness of the pipe adjacent to the external taper;
• a half round groove extending helically a plurality of turns along the length of the internal taper having the same pitch as the groove in the external taper;
• a round key member extending helically a plurality of turns along both grooves for locking the external and internal pipe joint moieties together, the key member having sufficient ductility for plastically deforming in shear and redistributing longitudinal loads along the length of the pipe joint;
• a first sealing surface outside the pipe between the end of the key member and the end of the pipe;
• a second sealing surface inside the coupling facing the first sealing surface;
• a pair of spaced apart circumferential elastomeric seals between the first and second sealing surfaces;
• a sealant between the elastomeric seals and adhered to both surfaces, the sealant being sufficiently elastic for accommodating the maximum longitudinal shear strain of the pipe joint;
• a sealant injection passage through a wall of the coupling between the elastomeric seals for injecting sealant between the elastomeric seals after the pipe joint is assembled;
• and
• a bleed passage through a wall of the coupling between the elastomeric seals for releasing air from between the elastomeric seals as sealant is injected.