Test Apparatus for On-line Butt-Welding Evaluation of Aluminum Layer in PEX-AL-PEX Multilayer Pipes

Abstract

Considering the advantages of multilayer pipes over metal and single layer ones as well as their new and increasing application in construction industry, testing these pipes has come into consideration to guarantee the quality of the pipes, and, consequently, prolong their life and increase the quality of building. A most prominent factor in multilayer pipes is the longitudinal seam-weld. If the aluminum layer is applied without welding, it may not affect the pipe's strength. The welding normally employed involves butt or overlap using laser, ultrasonic, or tungsten inert gas (TIG) techniques. A defect-free weld can play a significant role in the pipe's strength. Thus, a defect-free weld on the aluminum layer is a major factor in guaranteeing pipe's quality. In this article, an apparatus for on-line testing of aluminum layer seam weld in multilayer pipes is presented which functions via an inductive proximity sensor. Finally, the results of several tests and defects detected are described.