Precompressed piping system for handling cryogenic fluid

Claim 1

In a piping system having a plurality of inner pipe sections joined together to form a conduit for carrying fluid and a plurality of outer pipe sections joined together to form an insulating jacket for the inner pipe sections, wherein the improvement includes means at each joinder between pipe sections for precompressing said pipe sections, comprising: a first inner pipe section having a coupler including a flange attached to one end thereof, said flange having flat face and flat rear portions lying in planes substantially normal to the longitudinal axis of said first inner pipe section, said coupler further including an annulus extending from the face portion of said flange to form the unattached end of said coupler, a first outer pipe section surrounding said first inner pipe section and having a coupler including a flange attached to one end thereof, said outer pipe section flange having a flat face portion and a flat rear portion lying in planes normal to the longitudinal axis of said first outer pipe section and a set of apertures therein, said first inner pipe section being slightly longer than said first outer pipe section such that said one end of said first inner pipe section and the flange thereof extend out from said first outer pipe section beyond said one end of said first outer pipe section, a second inner pipe section having a coupler including a flange attached to one end thereof, said second inner pipe section flange having a flat face portion and a flat rear portion lying in planes substantially normal to the longitudinal axis of said second inner pipe section, said second inner pipe section coupler having an annular sleeve extending from the face portion of said second inner pipe section flange to form the unattached end of said second inner pipe section coupler, said sleeve being adapted to fit over the annulus of said first inner pipe section coupler, a second outer pipe section having a coupler including a flange attached to one end thereof, said last mentioned flange having a flat face portion lying in a plane substantially normal to the longitudinal axis of said second outer pipe section, and a set of apertures formed therein positioned and formed to mate with the apertures of said first outer pipe section, and means for clamping the flanges of said outer pipe sections together with the apertures thereof in alignment so as to draw the flat face portions of said outer pipe section flanges towards each other, the flat face portion of said second outer pipe section flange being drawn into abutment against the flat rear face of said second inner pipe section and the flat face portion of said first outer pipe section flange being drawn into abutment against the flat rear portion of said first inner pipe section, with the sleeve of said second inner pipe section coupler engaging the annulus of said first inner pipe section coupler and applying pressure thereagainst as the outer pipe section flanges are drawn towards each other, thereby longitudinally compressing the first inner pipe section.