94久久国产乱子伦精品免费,色噜噜一区二区三区,夜夜嗨av一区二区三区,成人av无码一区二区三区,性欧美大战久久久久久久,丁香六月久久婷婷开心,少妇人妻偷人精品免费视频,久久午夜无码鲁丝片午夜精品,日本大骚b视频在线,色欲av永久无码精品无码蜜桃

Products Information：

Generally , 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 Comifo lock forming mahicnes . The pittsburgh seam shows much better results and can also be used for a higher pressure.

Vertical duct seam closer is what we highly recommed . 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 ( penning ) . Disadvantages of such peening inclufe the time required and the almost intolerable noise produced . 

The latest desigh in seaming technology is  now available . At the pittsburgh joint . the individual seams are called pittsburgh seam ( pittsburgh lock ) and standing seam ( right angle lock ) . 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 mahcine .