Conduit system with expansion coupling

A conduit system comprising a plurality of insulated conduit units joined end-to-end in sealed and insulated expansible and contractible relation, each unit having an internal length of pipe, an external tubular jacket, and a mass of insulation between the pipe and jacket, each pipe having a male end projecting beyond the jacket and insulation and a female opposite end, said female end having a coupling tube telescoped thereover and projecting axially therefrom, a bond integrating the telescoped end of the coupling tube with the pipe in fixed sealed relation, said coupling tube projecting beyond the jacket and insulation and having an internal groove adjacent the projected end thereof, an elastometric O-ring in said groove, the male end of one unit snugly slidably fitted in the coupling tube on the female end of an adjacent unit and sealed therewith by said O-ring, a flexible insulation ring squeezed between and in contact with the insulation of adjacent units receiving the male end of one unit therethrough and embracing and contacting the projecting end of the coupling tube, a jacket sleeve embracing the insulation ring and the ends of the jackets of adjacent units, said male end of said internal length of pipe of each unit being shiftable in said insulation ring and mass of insulation to accommodate expansion and contraction without shifting said external jacket and said mass of insulation, said insulation ring positioning the termal end of said male end of the pipe in said coupling tube axially between the O-ring and the terminus of the adjacent pipe in the coupling tube, and means sealingly joining the jacket sleeve with the jackets whereby the male ends of the units are slidably sealed with the female ends of adjacent units to accommodate expansion and contraction of the conduit system and the mated conduit ends are insulated by the insulation ring with the insulation ring being sealed by the jacket sleeve.