Face-to-Face Positive Restrained Rotating Pipe Flange

A flanged ductile iron pipe spool for connecting two lengths of pipe, comprising:

• a centrifugally cast length of hubless ductile iron pipe of nominal size, thickness, and allowance for casting tolerance, having a flared bell end, a threaded spigot end, and an outer diameter;
• and
• a first annular ductile iron flange of said nominal size coupled to said threaded spigot end, having a threaded inner longitudinal surface, an outer longitudinal surface, a first basal surface, a second basal surface, and a plurality of evenly spaced circular bolt holes connecting the first basal surface to the second basal surface;
• wherein the improvement comprises:
• a second annular ductile iron flange of said nominal size coupled to and configured to rotate longitudinally around said pipe, having an outer longitudinal surface and a non-threaded inner longitudinal surface defining an inner diameter, said inner diameter containing the outer diameter of said pipe, also having a first basal surface, a second basal surface, and a plurality of evenly spaced circular bolt holes connecting the first basal surface to the second basal surface, said first basal surface having an annular counterbore adjacent to said non-threaded inner longitudinal surface, said counterbore having a longitudinal thickness equivalent to the sum of said nominal thickness and said nominal allowance and a radial thickness equivalent to the sum of between 1.5 and 2.5 times said nominal thickness and said nominal allowance;
• and
• said bell end machined to an annular pipe stub configured to recess into said counterbore, having a longitudinal thickness equivalent to said nominal thickness and a radial thickness equivalent to between 1.5 and 2.5 times said nominal thickness.

An annular ductile iron flange of nominal size, comprising:

• an outer longitudinal surface;
• an inner longitudinal surface defining a first inner diameter, said inner diameter exceeding the outer diameter of a length of centrifugally cast ductile iron pipe of said nominal size;
• a first basal surface having an annular counterbore, said counterbore having a longitudinal depth equivalent to the sum of said nominal thickness and said nominal allowance and a radial depth equivalent to the sum of between 1.5 and 2.5 times said nominal thickness and said nominal allowance;
• a second basal surface;
• and
• a plurality of evenly spaced circular bolt holes connecting said first basal surface and said second basal surface.

A connector for ameliorating misalignment of flange connected ductile-iron pipe, comprising:

• a centrifugally cast length of hubless ductile-iron pipe of nominal size, thickness, and allowance for casting tolerance, said pipe having a flared belt end, an externally threaded spigot end, and a first outer diameter;
• a first annular ductile iron flange of said nominal size, said first flange having an outer longitudinal surface and an inner longitudinal surface defining a first inner diameter, said first inner diameter greater than said first outer diameter, said first flange having a first basal surface and a second basal surface, said first basal surface having an annular counterbore, said counterbore having a longitudinal depth equivalent to the sum of said nominal thickness and said allowance and a radial depth equivalent to the sum of between 1.5 and 2.5 times said nominal thickness and said allowance, said first flange having a plurality of evenly spaced bolt holes connecting said first basal surface and said second basal surface, said first flange configured to rotate longitudinally around said pipe;
• said bell end machined to an annular pipe stub, said pipe stub having a longitudinal thickness equivalent to said nominal thickness and a radial thickness equivalent to between 1.5 and 2.5 times said nominal thickness, said pipe stub configured to recess into said counterbore;
• and
• a second annular ductile iron flange of said nominal size, said second flange having an outer longitudinal surface and a threaded inner longitudinal surface, said second flange having a first basal surface and a second basal surface, said second flange having a plurality of evenly spaced bolt holes connecting said first basal surface and said second basal surface, said threaded inner longitudinal surface coupled to said spigot end.