Tube making machine with diameter control and method

Abstract

A spiral pipe forming system which includes automatic diameter or dimension sensing and control.

1 . Apparatus for forming a spiral pipe, comprising: apparatus for forming a spirally wound sheet, the apparatus including inner and outer pressure rolls engaging and crimping together adjacent edges of the spirally wound sheet; a sensing system for monitoring changes in the diameter of the spirally wound sheet as it is formed and responsively generating signals including information regarding changes; and a system responsive to the output signals for moving the inner and outer pressure rolls in unison radially inward or outward relative to the axis of the pipe to offset change in diameter. 
   
   
       2 . A method of forming a spiral pipe having controlled diameter, comprising: forming a spirally wound sheet having adjacent edges; crimping adjacent edges of the sheet together; monitoring the diameter of the spirally wound sheet for changes therein; responsive to change in the diameter, generating signals including information regarding the change; and responsive to the signals, moving the adjacent edges of the spirally wound sheet together radially inward or outward relative to the axis of the spirally wound sheet to offset the change in diameter.