Plastics fitting for tapping into plastic gas and water mains - has cutter bush that screws through sleeve insert to trepan hole in mains pipe and then functions as stop valve spool

摘要

The fitting is made in two halves (10, 11) clamping onto the mains pipe (13), the upper half being sealed by welding or cementing (54). As an integral part of the upper half is a T-pipe with a main axis piece (17) and a branch piece (18). In the bore of the main axis piece is a sleeve insert (20). Screwable along the sleeve axis between an upper collar (23) and bottom collar (24) is a cutter bush (30) with a toothed cutting edge (34) which can be screwed down to trepan a hole (15) in the mains pipe. The cutter bush is screwed out of the trepanned hole with a spindle (60). The fitting is now transformed into a stop valve in which the cutter bush becomes the valve spool and seals against upper and lower sealing rings (37, 57). ADVANTAGE - Fitting performs dual functions of cutting tool and valve.