General three different seams are common in the industry to
connect the corners of the ducts: button lock seam, Pittsburgh seam
and Duct seam. Button snap lock and Pittsburgh lock can be produced
on the Dingcheng lock forming machines. The Pittsburgh seam shows
much better results and can also be used for a higher
pressure.
Whisper-Loc Seam Closer are available in the horizontal or
vertical and close pittsburgh seams. Pittsburgh joint is commonly
used to join the seams of metal ducts. Seam closing has
traditionally been accomplished by manually hammering the margin of
the seam against the duct wall (peening). Disadvantages of such
peening include the time required and the almost intolerable noise
produced.
The latest design in seaming technology is now available. At
the Pittsburgh joint, the individual seams are called Pittsburgh
seam(pittsburgh lock) and standing seam(right angle flange). On a
Pittsburgh joint, the operator pushes the standing seam into the
Pittsburgh seam, fastens them to each other and closes the joint on
a seam machine.
