Thermoplastic element for protection against corrosion in the thermofusion coupling of a thermoplastic tube

Abstract

It is the object of the present invention a thermoplastic element for the protection against corrosion in the thermofused splicing of a thermoplastic tube to a thermoplastic connection, which element has the shape of a fully thermoplastic tubular sleeve, able to be introduced into a socket mouth formed by the expansion of the tube end, said splice element bearing only one internal diameter and two external diameters which define a cylindrical external portion of larger diameter and a tubular projection which diameter is smaller than the former, and which is introduced into the thermoplastic tube, a lateral wall of the external portion defining a front butt of said thermoplastic element against the end of the thermoplastic tube. Said splicing element also exhibits an auxiliary ring which operates as a reference point for the assembly thereof.

1 . A protection element against corrosion in the thermofused splice of a thermoplastic tube (A) which includes an intermediate metal layer between two thermoplastic layers, with a thermoplastic connection (B), characterized in that said element has substantially the shape of a tubular sleeve fully premoulded on thermoplastic material, to be applied into a socket mouth (e) formed by the expansion of the end of said thermoplastic tube (A), said corrosion-protecting element exhibiting a single internal diameter and two external diameters which define: an external cylindrical portion (c) having a rectangular longitudinal section and exhibiting a side wall (P) abutting against end ( 2 ) of thermoplastic tube (A), and a tubular projection (c′) which diameter is smaller than that of said external portion (c), to be introduced into said socket mouth (e) and having an internal diameter which is substantially identical to tube (A) internal diameter, said protection element being attached to socket mouth (e) of said tube by means of thermofusion between said abutting lateral wall (P) and the edge of both thermoplastic layers of said tube, and between said tubular projection and the adjacent portion of the internal layer of the tube, in a stage previous to the interfusion between tube end and thermoplastic connection.  
     
     
         2 . The protection element against corrosion according to  claim 1 , characterized in that height of abutting side wall of the external portion is substantially equal to the thickness of the three layers of the tube.  
     
     
         3 . The protection element against corrosion according to  claim 1 , characterized in that its internal diameter is substantially equal to the internal diameter of the thermoplastic tube.  
     
     
         4 . The protection element against corrosion according to  claim 1 , characterized in that the socket mouth is expanded 10% to 20% of the diameter of the intermediate metal layer of said tube.  
     
     
         5 . The protection element against corrosion according to  claim 1 , characterized in that it also includes an auxiliary ring, which spatially extends around said external portion of the protection element by way of a collar and which is joined thereto by means of a thin intermediate wall ( 12 ).  
     
     
         6 . The protection element against corrosion according to  claim 5 , characterized in that said auxiliary ring is provided with a plurality of projections extending on the periphery thereof.  
     
     
         7 . The protection element against corrosion according to  claim 5 , characterized in that said thin intermediate wall is dimensioned in such a way that it may only be detached from the external portion when the thermofusion temperature is as required, acting by way of temperature control of thermofusing machine T-II nozzle.  
     
     
         8 . The protection element against corrosion according to  claim 5 , characterized in that said auxiliary ring exhibits a colour which contrasts with that of the thermoplastic tube.