Process for replacing a length of buried pipe

A method for replacing a buried section of old pipe, which extends through a passageway formed in the soil, with a corresponding section of new pipe, comprising:

• (a) excavating first and second open pits at the first and second ends of the pipe section, to thereby expose the pipe at those points;
• (b) breaking up at least part of the exposed segments in each of the pits;
• (c) inserting, in the first pit, first means for tripping a rod string;
• (d) inserting, in the first pit, means for longitudinally splitting old pipe being advanced thereover as said pipe enters the pit, said splitting means being adapted to enable the rod string to pass therethrough;
• (e) tripping a string of rods from the first pit to the second pit through the bore of the old pipe section, said string extending through the splitting means;
• (f) attaching to the second end of the rod string a tool assembly comprising, in sequence, second means for bearing against the annular second end face of the old pipe section, third means for expanding the diameter of the passageway, and fourth means for engaging and pulling new pipe into the expanded passageway behind the old pipe as the latter is pulled toward the first pit, said fourth means having a section of new pipe associated therewith;
• (g) tripping the rod string through the passageway, thereby simultaneously advancing the old pipe out of the passageway and into the first pit, longitudinally splitting the old pipe as it reaches the first pit, expanding the diameter of the passageway, and advancing the new pipe into the expanded passageway to replace the old pipe with the new pipe.

A method for replacing part of a buried section of old pipe, which extends through a passageway formed in the soil, with a corresponding section of new pipe, comprising:

• (a) excavating first, second and third open pits at the first and second ends of the section and at a point between its ends, respectively, to thereby expose the pipe at those points;
• (b) breaking up at least part of the exposed segments of old pipe in each of the pits;
• (c) inserting, in the first pit, first means for tripping a rod string;
• (d) inserting, in the third pit, means for longitudinally splitting old pipe being advanced thereover as said pipe enters the pit, said splitting means being adapted to enable the rod string to pass therethrough;
• (e) tripping a string of rods from the first pit to the second pit through the bore of the old pipe section, said string extending through the splitting means;
• (f) attaching to the second end of the rod string a tool assembly comprising, in sequence, second means for bearing against the annular second end face of the old pipe section, third means for expanding the diameter of the passageway, and four means for pulling new pipe into the expanded passageway behind the old pipe a the latter is pulled toward the first pit, said fourth means having a section of new pipe associated therewith;
• (g) tripping the rod string from the second pit to the third pit, thereby simultaneously advancing the old pipe out of the passageway and into the third pit, longitudinally splitting the old pipe as it reaches the third pit, expanding the diameter of the passageway between the second and third pits, and advancing the new pipe into the expanded passageway to replace old pipe with new pipe.

Apparatus for replacing a section of buried old pipe extending between first and second pits from each of which at least part of the segment of exposed old pipe has been removed to make accessible the bore of the old pipe section, comprising:

• first means, positioned in the first pit, for tripping a rod string in a generally horizontal plane;
• a first rod string extending through the bore of the old pipe section and into the second pit;
• means, located in the first pit, for breaking up old pipe as it is advanced into the first pit;
• a section of new pipe positioned at the second pit;
• and
• a tool assembly attached to the second end of the rod string, said tool assembly comprising a string of sequentially connected components, said components comprising second means for bearing against the annular second end face of the old pipe, third means for expanding the old pipe passageway as said means passes therethrough, and means for engaging and pulling the new pipe into the expanded passageway behind the old pipe.

Apparatus for replacing a section of buried old pipe extending between first, second and third pits, said third pit being positioned between the others and the exposed segments of pipe having been substantially removed to clear the pits and make accessible the bore of the old pipe section, comprising:

• first means, positioned in the first pit, for tripping a rod string in a generally horizontal plane;
• a first rod string extending through the bore of the old pipe section and into the second pit;
• means, located in the third pit, for breaking up old pipe as it is advanced thereover into the third pit;
• a section of new pipe positioned at the second pit;
• and
• a tool assembly attached to the second end of the rod string, said tool assembly comprising a string of sequentially connected components, said components comprising second means for bearing against the annular second end face of the old pipe, third means for expanding the old pipe passageway as said means passes therethrough, and means for engaging and pulling the new pipe into the expanded passageway behind the old pipe.