Integral ductwork diffuser

Abstract

Apparatus and a corresponding method for forming from a strip of sheet metal stock material a length of spiral duct that includes an integral diffuser. A perforator forms perforations in the strip at at least selected intervals. A machine forms the strip, after perforation, into spiral seamed duct.

What is claimed is:  
     
         1 . Apparatus for forming from a strip of sheet metal stock material a length of spiral duct that includes an integral diffuser, said apparatus comprising: 
 a perforator for forming perforations in the strip at at least selected intervals; and    a machine for forming the strip, after perforation, into spiral seamed duct.    
     
     
         2 . The apparatus of  claim 1 , wherein said perforator forms clusters of perforations at intervals corresponding to the circumference of the spiral seamed duct being formed.  
     
     
         3 . The apparatus of  claim 1 , wherein said perforator comprises a punching roll.  
     
     
         4 . The apparatus of  claim 1 , wherein said perforator comprises a stationary punch.  
     
     
         5 . The apparatus of  claim 1 , which further comprises a controller connected for coordinating operation of said perforator and of said machine for forming the strip into spiral seamed duct.  
     
     
         6 . Apparatus for forming, from a strip of sheet metal stock a length of 360° perforated spiral duct, said apparatus comprising: 
 a perforator for forming perforations in the strip in a continuous manner and  
 a machine for forming the strip, after perforation, into spiral seamed duct.  
 
     
     
         7 . A method for forming a length of spiral duct that includes an integral diffuser, said method comprising: 
 providing a strip of sheet metal stock material;    perforating the strip at at least selected intervals; and    employing a machine to form the strip into spiral seamed duct.    
     
     
         8 . The method of claim, which comprises perforating the strip to form clusters of perforations at intervals corresponding to the circumference of the spiral seamed duct being formed.