1
Long George M: Add-on stopper valve for existing piping. Institute of Gas Technology, Dominik Knechtel Godula & Demeur, March 26, 1974: US3799182 (39 worldwide citation)

The invention comprises an add-on valve which includes, generally, a holding chamber which is adapted to be fixedly secured to a pipe, a gate valve assembly which is adapted to be removably affixed to the holding chamber, a saw chamber assembly including a saw for sawing an opening into the pipe, a ...


2
Long George M: Add-on slide gate valve for existing piping. Institute of Gas Technology, July 31, 1973: US3749108 (8 worldwide citation)

The invention comprises a valve stopper which includes, generally, a rubber patch clamp which is used in combination with a slide gate valve assembly, both of which can be added to an existing fluid piping system without shut-down or interruption of flow. The rubber patch clamp first is affixed to t ...