The present invention relates to pipe fittings for use in building pipe lines for delivering, particularly but not exclusively, cooking and heating gas.
Pipe fittings are in abundant use for building pipe lines to deliver fluid from one location to another. They are available in a vast variety of forms and sizes for joining pipes together in different layouts. A typical low-cost material used for producing pipe fittings and pipes is iron, and the final products are usually galvanised with a coating of zinc or like for protecting the base material against rusting.
Pipes are cut with screw threads for joining purposes, whereby the base material at the joining positions is inevitably exposed. The base material adjacent to the joints upon completion may remain exposed, which would require protection. At present, paint is normally used for that purpose but is found to be unreliable.
The invention seeks to mitigate or at least alleviate such a problem by providing an improved pipe fitting.
According to the invention, there is provided a pipe fitting comprising a hollow body and at least one open end for connection to a pipe. This end is pre-formed with internal screw threads for connection and includes an integral extension collar. The collar has an inner diameter relatively larger than that of the screw threads for surrounding unused trailing screw threads of said pipe and forming an annular gap there between to hold a sealing compound. The collar has a wall of a comparable thickness as that of the end behind it and an outer diameter relatively larger than that of the end behind it.
In a preferred embodiment, the screw threads are slightly tapered outwards at a small angle with respect to the axis of the end.
It is preferred that for the pipe fitting to be made of a galvanised iron material.
The pipe fitting may be in the form selected from the group of an elbow joint, a T-shaped joint, a straight joint and a end cap.
USPTO Backgrounds
USPTO Backgrounds