Repair coupling for piping systems
A repair coupling for joining a first pipe with a second pipe includes (a) a hollow body having a first open end, a second open end, and a passageway the interior surface of the body defining a peripheral, helical body edge terminating in a body edge locking lug, and (b) a hollow tubular insert slidably disposed within the body, the tubular insert having a first open end and a second open end, the tubular insert defining a passageway he exterior surface of the tubular insert defining a peripheral, helical insert edge terminating in an insert edge locking lug. The tubular insert is slidable between (i) a first insert position wherein the helical insert edge is in contract with the helical body edge and (ii) a second insert position wherein the helical insert edge is spaced apart from the helical body edge.
1. A repair coupling suitable for joining a first pipe in fluid tight communication with a second pipe, the repair coupling comprising:
(a) a hollow body having a first open end, a second open end, an exterior surface, an interior surface and a longitudinal axis, the body defining a linear passageway between the first open end of the body and the second end of the body, the linear passageway having an interior diameter, the interior surface of the body, proximate to the first open end of the body, defining a peripheral, helical body edge terminating in a body edge locking lug;
(b) a hollow tubular insert slidably disposed within the body, the tubular insert having a first open end, a second open end, an exterior surface, an interior surface, an external diameter and a longitudinal axis, the tubular insert defining a linear passageway between the first open end of the tubular insert and the second open end of the tubular insert, the exterior surface of the tubular insert defining a peripheral, helical insert edge terminating in an insert edge locking lug; and
(c) a sealing element for sealing the exterior surface of the tubular insert with the interior surface of the body;
wherein the tubular insert is slidable between (i) a first insert position wherein the helical insert edge is in contract with the helical body edge, and (ii) a second insert position wherein the helical insert edge is spaced apart from the helical body edge; and
wherein, when the insert is in the first insert position, the rotation of the body in a first direction causes the body edge locking lug to engage the insert edge locking lug and to thereby rotate the tubular insert, and the rotation of the body in a direction opposite to the first direction causes the tubular insert to travel towards the second open end of the body.
2. The repair coupling of claim 1 wherein the helical insert edge is sized and dimensioned to engage between about 270° and about 360° of the helical body edge.
3. The repair coupling of claim 1 wherein, when the insert is in the first insert position, the rotation of the body in a first direction causes the body edge locking lug to engage the insert edge locking lug and to thereby rotate the tubular insert, and the rotation of the body in a direction opposite to the first direction causes the tubular insert to travel towards the second open end of the body a distance of at least about 0.125 inches.
4. The repair coupling of claim 1 wherein the body comprises a proximal portion and a distal portion.
5. The repair coupling of claim 4 wherein the proximal portion is welded to the distal portion.
6. The repair coupling of claim 1 wherein the sealing element comprises at least one circular gasket disposed within a circumferential groove in the exterior surface of the tubular insert.
7. The sealing element of claim 6 wherein the at least one gasket is one or more O-rings.