| 摘要 |
<p>A fitting formed with a circular flange formed coaxially with a spigot which is formed along its length with a series of frusto-conically shaped, axially spaced apart, sealing rings which are formed attheir enlarged ends with respective annular holding rings. A metallic stiffener tube is received telescopically in the fitting to provide support against radial inward collapse thereof. The spigot may be formed adjacent the flange with an enlarged extremity remote from the flange with a reduced in diameter stress relief nipple. A finishing sleeve is provided for telescopical receipt over a polyethelene pipe fitted over the spigot. Thus the spigot may be inserted into the end of the plastic pipe to expand such pipe to an expanded configuration. The finishing sleeve may then be drawn telescopically over the expanded configuration to press the wall of the polyethelene pipe radially inwardly to compress the polyethelene material between the stiffener tube and finishing collar to flow the pipe wall material radially inwardly into the grooves formed between adjacent ones of the sealing rings to thereby form a plastic coupling completely surrounding the metal stiffener tube to isolate it from soil in which the pipe might be buried. The method includes the steps of severing a leaking section from a plastic pipe and inserting such a double ended fitting as a substitute for the severed section.</p> |
