Wall thickness meter for extrusions - has ultrasonic heads enabling speed of sound through extrusion to be measured, and further test heads use this to provide thickness values

摘要

An ultrasonic device measures the wall thickness of extruded tubes, other sections, tapes or cable wrappings where the equipment has an extruder die and outer tool, a cooling system adjacent (and a water chamber under low pressure in particular), and a gauging tool (and particularly one with a measuring head functioning through the tube etc.). The die has at least one further ultrasonic test head which transmits its ultrasonic signal through the material in the extruder components or those immediately beyond the extruder; the value measured for a time T allows a computer to calculate the speed of sound through the extruded material from the geometry of the material; from this value and that provided by the ultrasonic head in or immediately beyond the gauging device for the time T the wall thickness of the extrusion is derived. ADVANTAGE - The system produces highly accurate thickness measurements with a relatively simple set-up