Pipe lap joint with improved sealing slot for increased circumferential closure

A pipe lap joint, comprising:

• an inside pipe having a pipe end;
• an outside pipe having a pipe end with a sealing zone extending over at least a portion of said inside pipe end and including a collapsible sealing slot;
• said sealing slot having a first sidewall with a first tooth and recess, a second sidewall with a second tooth and recess, and an end wall, wherein said first and second sidewalls are generally parallel to one another and are arranged such that said first tooth opposes said second recess in a generally complementary fashion, and said second tooth opposes said first recess in a generally complementary fashion, and wherein at least one of said first and second recesses includes an outboard edge generally facing an open end of said sealing slot, an inner edge generally facing the opposing sidewall, and an inboard edge generally facing said end wall;
• and
• a band clamp extending over at least a portion of said sealing zone, wherein tightening of said band clamp causes said sealing slot to collapse such that said first tooth is received by said second recess and said second tooth is received by said first recess.

A pipe for use in conjunction with a second pipe and a pipe clamp to form a pipe lap joint, comprising:

• a section of pipe having a diametrically-enlarged pipe end and a collapsible sealing slot extending axially into said pipe end from an end surface of said pipe section;
• said sealing slot having first and second sidewalls that are circumferentially separated by a gap, said sidewalls each defining a tooth and a recess with the tooth of the first sidewall being axially aligned with the recess of the second sidewall, and the recess of the first sidewall being axially aligned with the tooth of the second sidewall such that when said sealing slot is collapsed by a radially-inward force on said pipe end, said tooth of each sidewall fits into the recess of the other sidewall;
• and
• wherein said teeth each have a circumferentially-extending edge that engages the edge of the other tooth during collapsing of said sealing slot, whereby said edges form a seal between said sidewalls while said teeth and said recesses enable said sealing slot to undergo a significant amount of circumferential closure.

A method for telescopically coupling the ends of an inside and an outside pipe together, comprising the steps:

• (a) providing an inside pipe end;
• (b) providing an outside pipe end having a sealing zone with a collapsible sealing slot, said sealing slot includes a first sidewall with a first tooth and recess, a second sidewall with a second tooth and recess, and an end wall, wherein said first and second sidewalls are generally parallel to one another and are arranged such that said first tooth opposes said second recess in a generally complementary fashion, and said second tooth opposes said first recess in a generally complementary fashion;
• (c) providing a band clamp having a clamping band and a tightening mechanism;
• (d) placing said band clamp around said outside pipe end and over said sealing zone;
• (e) inserting said inside pipe end within said outside pipe end so that said sealing zone extends over at least a portion of said inside pipe end;
• and
• (f) forcing said first tooth into said second recess and said second tooth into said first recess by tightening said tightening mechanism so that said clamping band applies a radially inward force to at least a portion of said sealing zone.