Image Number 4 for United States Patent #6131954.
A method and apparatus are disclosed for a thermoplastic profile wall pipe joint or weld assembly without the use of a coupler to provide for a leak free pipe joint with substantially flush interior and exterior surfaces. The pipe joint consists of configuring the two pipe ends to be joined by removing substantially all of a first wall and the helical rib from the first pipe end, removing a portion of the helical rib from the second pipe end, coupling the pipe ends together and heating the weld assembly couple to fusion weld the pipe ends together. An electrical resistance element is provided for and placed within the pipe joint to provide the required heat. Also disclosed is the use of a thermoplastic sheet with the electrical resistance element to allow the end margins of the electrical resistance element to overlap without shorting by separating the end margins radially from one another and to allow for a more uniform fusion welded pipe joint. The resulting joint is a leak free joint with no interior flow obstructions or exterior collars or protrusions without the need for a coupler.