A patent dispute that had gone underground for more than a year is boiling to the surface again.
Pipe Liners Inc. of New Orleans, a wholly owned subsidiary of CSR Hydroconduit Inc. of Houston, on Dec. 9 reopened its patent infringement lawsuit against American Pipe & Plastics Inc. of Binghamton, N.Y.
Pipe Liners first filed the suit in 1995 in U.S. District Court in Galveston, Texas. The suit contends American Pipe infringed on two of seven patents Pipe Liners holds on its sewer line rehabilitation process involving folded plastic pipes.
Proceedings paused in early 1996 when American Pipe requested a review of the patents in question, Nos. 4,985,196 and 4,986,951. The U.S. Patent and Trademark office in Washington ruled earlier this year that Pipe Liners' patents were valid, Charles Curtis, general counsel for Pipe Liners said, adding the patent office action opened the way for the suit to be reactivated.
But American Pipe lawyer Charles Conan of Syracuse, N.Y., accused Pipe Liners of ``inequitable conduct'' before the patent review board and said his client ``is confident Pipe Liners' claims will be rejected in court.''
American Pipe also holds a number of patents for its pipe rehabilitation process, but the details of those patents are not in dispute in the current case, Conan said.
A number of companies promote similar methods of fixing bad sewer pipes without having to dig them up. The disputed process involves inserting a folded length of plastic pipe into an existing line, then expanding the insert with steam. Installers use small robots with television cameras to inspect the pipe and cut openings for individual connections into the main pipe.
American Pipe and Pipe Liners differ in the composition of the pipe itself, Curtis said. Pipe Liners uses high density polyethylene while American Pipe uses a PVC blend. But the patents at issue in the suit describe the process, not the materials used, Curtis said.
Pipe Liners developed the first commercial process for ``hard'' pipe rehabilitation in 1988, Curtis said. He distinguished the ``hard'' process using extruded plastics products from the ``soft'' processes using fabrics cured in place with a thermoset resin.
Curtis could not specify what remedy Pipe Liners is seeking with the lawsuit. He also declined to comment on any actions his company could take against other companies using similar methods.
Patent re-examinations are fairly rare, according to Lisa Sigorsky, a patent office spokeswoman. The only reason a patent can be re-examined is a claim of prior art that was not included in the initial patent procedure, she said.
An appeal process is available to patent holders whose patents are canceled or modified, but not to third parties who request review of someone else's patent, Conan said.
