Method for joining plastic pipe

Abstract

A simpler method and apparatus for joining plastic pipe is provided by creating a flange ring on the end of a plastic pipe, the flange ring being cut from a short length of a larger dimension plastic pipe selected or machined to fit closely over the outer diameter of the plastic pipe to provide a flange which may be bolted or fastened to a similar flange. A similar method may be used to provide a connection by means of a coupling.

1 .- 6 . (canceled) 
     
     
         7 . Method of joining lengths of plastic pipe, comprising providing first lengths of plastic pipe having an outside diameter; providing second lengths of plastic pipe having an inner surface with an inside diameter equal to or slightly smaller than said outside diameter; machining said inner surface, if necessary, to enable said inner surface to fit snugly over said outside diameter; cutting a length of said second length of plastic pipe to form a coupling; inserting one of said first lengths of pipe in one-half of the length of the coupling; inserting a second of said first lengths of pipe into the other half of the length of the coupling; and heat welding said one and said second of said first lengths of pipe to said coupling, by bringing them to a temperature at which they melt. 
     
     
         8 . Method as claimed in claim  1  wherein an internal diameter of the coupling and outer surfaces of said one and of said second of said first lengths of pipe are heated before inserting said one and said second of said first lengths of pipe in the coupling. 
     
     
         9 . Method of forming a length of plastic pipe adapted to be joined to a further length of plastic pipe, by bringing them to a temperature at which they melt, comprising: providing a first length of plastic pipe having an outside diameter; selecting a second length of plastic pipe having an inner surface with an inside diameter equal to or slightly less than said inner surface to fit snugly over said outside diameter; cutting a short length of said second length of pipe to form a ring, applying said ring as a flange on said outside diameter; and fastening said flange to said first length of pipe. 
     
     
         10 . Method as claimed in claim  3 , including machining said inner surface, if necessary, to enable said inner surface to fit snugly over said outside diameter; and wherein said first length of plastic pipe is a free standing pipe, and said flange being wholly cylindrical on its outer side. 
     
     
         11 . Method as claimed in claim  4  wherein said first and second lengths of plastic pipe are wholly polyolefin. 
     
     
         12 . Method as claimed in claim  4  wherein said polyolefin is polyethylene. 
     
     
         13 . Method of forming a length of plastic pipe adapted to be joined to a further length of plastic pipe, comprising: providing a first length of plastic pipe having an outside diameter; selecting a second length of plastic pipe having an inner surface with an inside diameter equal to or slightly less than said inner surface to fit snugly over said outside diameter; cutting a short length of said second length of pipe to form a ring, applying said ring on said outside diameter; and fastening said ring to said first length of pipe, wherein said first and second lengths of pipe are on-crosslinked. 
     
     
         14 . Method as claimed in  claim 7  wherein said ring is fastened to said first length of pipe by bringing said ring and said first length of pipe to a temperature at which they melt. 
     
     
         15 . Method as claimed in  claim 7  in which said ring is applied as a flange to said first length of pipe. 
     
     
         16 . Method as claimed in  claim 7  in which said ring has a length and is applied as a coupling to said first length of pipe by insertion of said first length of pipe into a first portion of the length of the ring, leaving a second portion of length of the ring available to receive an end of a further pipe. 
     
     
         17 . Method as claimed in  claim 10  in which the first length of pipe is inserted into half the length of the ring. 
     
     
         18 . Method as claimed in  claim 10  including a step of joining a further pipe to said first length of pipe by inserting an end of said further pipe in said second portion of the length of the ring.