1. Field of the Invention
The present invention relates to a gas service riser assembly and a ductile pipe to plastic pipe transition connection.
2. Description of the Prior Art
Plastic pipe such as polyethylene pipe is now utilized in most gas distribution systems. As a result, there are many applications where plastic pipe must be connected to metal and other forms of pipe. For example, above ground gas meters are generally connected by metal pipe to below ground plastic gas service pipe. The metal pipe and plastic pipe are often joined together in a gas service riser which extends from below ground to a gas meter above ground. Such riser assemblies have heretofore been comprised of a metal pipe which connects to the gas meter and contains a metal to plastic pipe transition connection therein. That is, the riser assembly comprises an outer metal pipe and an inner plastic pipe. The inner plastic pipe extends through and out of the outer metal pipe and the outer metal pipe provides protection to the inner plastic pipe.
The gas service riser assemblies developed and used heretofore have generally been used successfully, but the seal mechanisms utilized between the inside of the outer metal pipe and the outside of the gas pipe therein have generally been complex and difficult to assemble. Thus, there is a continuing need for improved gas service riser assemblies which are simple, involve the use of only a few parts and are readily assembled. Also, there is a continuing need for a ductile pipe to plastic pipe transition connection which is simple, involves only the use of a few parts and is readily assembled.