Tube butt joint detector for rolling mills - applies magnetic field and responds to field disturbances caused by gap variation

摘要

Magnetic field of detector, used for process control, is disturbed by the joint and this is sensed by elements which respond to magnetic field changes. Their output signals have marked differences in phase and amplitude which are utilized to trigger a control instruction. Method is not affected by errors caused by variations in the joint gap, in the tube dimensions or radial deflections, like mechanical feelers or light barriers. It is equally suitable for the detection of joints of billets or plates.