The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 21, 1998
Filed:
Jul. 19, 1996
Shinobu Satake, Tokyo, JP;
Tadao Yahata, Kanagawa-ken, JP;
Takashi Shigefuji, Tokyo, JP;
Shigeru Toyoda, Saitama-ken, JP;
Shuichi Yagi, Kanagawa-ken, JP;
Masaaki Itagaki, Kanagawa-ken, JP;
Tokyo Gas Co., Ltd., Tokyo, JP;
Abstract
There is provided a method of lining an existing underground main pipe involving a branch pipe. The method comprises injecting a necessary amount of resin into the branch pipe from an open end thereof, introducing behind the resin a pig apparatus into the branch pipe, applying a positive pressure behind the resin and pig apparatus in the branch pipe to cause the resin and pig apparatus to move forward until the entire internal surface of the branch pipe is lined with the resin by means of the pig apparatus and until the pig apparatus reaches and slightly passes beyond a branching position where the branch pipe is branching from the main pipe, applying a negative pressure behind the pig apparatus in the branch pipe to cause the pig apparatus to stop at the branching position such that the branch pipe is completely isolated from the main pipe, injecting a necessary amount of resin into the main pipe from an open end thereof, inserting behind the resin a lining pig into the main pipe, applying a positive pressure behind the resin and lining pig in the main pipe to cause the resin and lining pig to move through the main pipe along the entire length thereof, so as to form a resin lining layer on the internal surface of the main pipe.