Flexible Electrofυsion branching tee

The jointing of polyethylene gas and water pipes by means of electrically heated fittings (electrofusion) is widespread and successful. There are two basic categories of fittings, saddles and couplers. Couplers are designed to make a connection between the ends of pipes and saddles are for branching from the sides of carrier pipes. In both of the variations successful jointing depends partly on the control of the dimensions of mating parts. Specifically, the circular profile of the pipe is matched by the circular profile of the adjoining fitting.

In order to reduce costs, polyethylene pipes up to a diameter of 180mm can be supplied in coils, and dispensed into the laying trench from a suitable drum or trailer, thus reducing the number of joints required. A negative consequence of this procedure is the inevitable distortion of the pipe diameter caused by the coiling process. After uncoiling the 'memory' of the polyethylene material causes the pipe to retain its coiling curve and the ovality created by the process.

Prior to the connection of a fitting to the pipe it has been necessary to apply rounding and straightening clamps in order to reform the desirable circular profile and straighten the length to be joined.

Saddle fittings are designed to have a circular profile and are normally quite rigid in anticipation of matching a similar profile on the reformed pipe.

To overcome these problems the present invention proposes an electrofusion branching saddle having a flexible connecting surface 2 such that the surface is able to conform to oval and curved carrier pipes thus avoiding the need for pipe re-rounding clamps and other equipment. Application of the branching tee to the carrier pipe 3 is achieved by means of flexible straps 4, secured by fasteners 5. Tightening of the flexible fasteners causes the connecting surface 2 to make intimate contact with the carrier pipe 3, having the effect of a 'bandage', following the contours of the distorted pipe. Upstands 6 moulded into the outer surface of the connecting surface engage with holes in the flexible straps 4 to orientate the connecting means 5. Orientation is arranged to provide full visibility to the installer when working above the fitting in a typical installation trench (fig ~25&?5)

Fig ^Illustrates the ability of the flexible connecting surface to conform to the profile of oval pipes.

Fig ⁵ * ³ * illustrates the ability of the flexible connecting surface to confirm to curved pipes, typical of pipes dispensed from a coil.

An additional benefit of the flexible electrofusion branching tee is its ability to conform to a range of similar pipe sizes thus reducing the cost associated with conventional tees which are made specifically for one size only. <Eig$6. shows how the fitting can be used for several pipe sizes by the use of suitably sized flexible connecting straps. Reduction in mould tool costs, production costs and inventory costs is therefore achieved.