Method of producing helically corrugated metal pipe and related pipe construction

Abstract

A pipe manufacturing device and method provides for pipe diameter monitoring and responsive pipe diameter control. Various pipe configurations and pipe assemblies adapted for ease of in the field connection are also provided.

1 - 11 . (canceled)  
     
     
         12 . A method of manufacturing helically corrugated metal pipe, comprising the steps of: 
 (a) drawing a metal sheet off of a coil;    (b) corrugating the metal sheet to produce a corrugated metal strip;    (c) spiraling the corrugated metal strip and joining adjacent edges of the spiraled corrugated metal strip in a crimped manner to produce a helical seam;    (d) automatically monitoring diameter variations of pipe being produced;    (e) based upon the diameter monitoring, automatically varying pipe diameter in a manner to produce a pipe segment having a first end with a diameter that is larger than a diameter of a second end;    (f) working the first end to produce a substantially corrugation free bell end, and working the second end to produce a spigot end with an annular gasket seat.    
     
     
         13 . The method of  claim 12  wherein step (e) involves varying helix angle of the pipe segment along a length of the pipe.  
     
     
         14 . The method of  claim 12  wherein the bell end is produced with a entry lip that angles outward.  
     
     
         15 . The method of  claim 12  wherein step (f) includes forming one or more annular corrugations adjacent the substantially corrugation free bell end.  
     
     
         16 . A method of manufacturing helically corrugated metal pipe, comprising the steps of: 
 (a) drawing a metal sheet off of a coil;    (b) corrugating the metal sheet to produce a corrugated metal strip;    (c) spiraling the corrugated metal strip and joining adjacent edges of the spiraled corrugated metal strip to produce a helical seam;    (d) automatically monitoring diameter of pipe being produced;    (e) based upon the diameter monitoring, automatically varying pipe diameter;    (f) producing multiple pipe segments by cutting the helically corrugated metal pipe each time a specified length of pipe is produced;    (g) coordinating the pipe diameter variations of step (e) with the cutting operations of step (f) such that pipe segments are produced in the following sequence in a repeating manner: 
 (1) producing a pipe segment having a downstream end and an upstream end, a diameter of the upstream end larger than a diameter of the downstream end, then  
 (2) producing a pipe segment having a downstream end and an upstream end, a diameter of the upstream end smaller than a diameter of the downstream end.  
   
     
     
         17 . The method of  claim 16  wherein the diameter of the upstream end of each pipe segment of (g)(1) is substantially the same as the diameter of the downstream end of each pipe segment of (g)(2).  
     
     
         18 . The method of  claim 16  wherein, for each pipe segment of (g)(1), the upstream end is worked to produce a substantially corrugation free bell end, and the downstream end is worked to produce a spigot end with at least one annular corrugation.  
     
     
         19 . The method of  claim 16  wherein, for each pipe segment of (g)(2), the downstream end is worked to produce a substantially corrugation free bell end, and the upstream end is worked to produce a spigot end with annular corrugations.  
     
     
         20 - 36 . (canceled)  
     
     
         37 . A helically corrugated metal pipe assembly adapted for facilitating end-to-end connection in the field, comprising: 
 a tubular structure in the form of a spiraled corrugated metal strip with opposite side edges adjacent each other and joined together to form a helical seam along a length of the tubular structure, a central region of the tubular structure helically corrugated, a first end of the tubular structure worked to provide an annular structure, a bell fitting positioned on the first end of the tubular structure and having an end portion, shrink wrap material wrapped about the pipe assembly in a region to cover the annular structure and the end portion of the bell fitting, the shrink wrap heated to form fit to the pipe assembly thereby securing the bell fitting on the end of the tubular structure and providing a sealing function between the tubular structure and the bell fitting.    
     
     
         38 . The helically corrugated metal pipe assembly of  claim 37  wherein the annular structure is an annular gasket seat with an annular gasket therein, wherein the end portion of the bell fitting engages the annular gasket.  
     
     
         39 . The helically corrugated metal pipe assembly of  claim 37  wherein a second end of the tubular structure includes an annular gasket seat.