Patent ID: 6416692
Filing Date: 2002-07-09
Classification: F16L

Abstract:
A method of repairing leaking underground sewer pipes, comprising the steps of:(a) isolating a defective segment of a pipe having a wall including defects to be repaired; (b) everting a liner tube of flexible watertight material within said defective segment of a pipe, thereby placing said watertight material in contact with an interior surface of said segment of pipe to be repaired, by filling said liner tube with a fluid and placing said fluid under pressure sufficient to hold said watertight material tightly against said interior surface along at least a first portion of said defective segment of pipe to be repaired, to seal said defects in said wall of said first portion, thereby substantially preventing ingress of ground water into said first portion of said segment; (c) introducing a quantity of a fluid sealant into a second portion of said defective segment of said pipe adjacent said liner tube, and placing said sealant under pressure, thereby forcing an effective quantity of said sealant into said defects in said wall of said second portion of said defective segment of said pipe; (d) thereafter, withdrawing said liner tube from at least a first part of said first portion of said defective segment while keeping said sealant under said pressure and thereby simultaneously unsealing said defects in said wall of said first portion and forcing a quantity of said sealant into said first part of said first portion, and thereby forcing an effective quantity of said sealant into said defects in said wall located in said first part of said first portion of said detective segment; (e) thereafter, returning said liner tube into said first part of said first portion of said defective segment to seal said defects in said wall of said first portion while continuing to keep said fluid within said liner tube under said pressure for a predetermined period of time, thereby retaining said effective quantity of said sealant in said defects in said wall of said first part of said first portion of said defective segment of said pipe long enough for said sealant to cure sufficiently to plug said defects effectively and thereby to repair said defective segment of said pipe; (f) removing excess quantities of said fluid sealant from said second portion of said segment of said pipe before said excess quantities can cure, while continuing to keep said fluid within said liner tube under said pressure; and (g) subsequent to said predetermined period of time removing said liner tube and said fluid contained therein from said segment of said pipe.