Abstract: A method of calculating the thickness of a sheet material comprising directing a beam of photons against the sheet material from a photon source (1) located on one side of said sheet material (7), detecting reflected radiation from said sheet material in a first detector (2) located on the same side of said sheet material and detecting transmitted radiation in a second detector (5) located on the opposite side of the said sheet material, combining the signals of transmitted and reflected photon beams, measuring and processing the data from both detectors for a number of calibrating samples, obtaining the thickness as a function of the detected data and applying this function to determine the unknown thickness of a sample. Apparatus for carrying out the method of the invention is also disclosed.

Abstract: A method and system for measuring a profile of a strip of material produced in a reversing mill in which a direction of travel of the strip is reversible includes a single thickness gauge that measures the thickness of the strip and generates the thickness signals, and a moving device coupled to the gauge. The moving device controllably moves the gauge transversely to the strip so that the gauge measures the thickness of the strip and different points across a width of the strip in one pass of the strip through the gauge. The moving device maintains the gauge in a stationary position in another pass of the strip through the gauge such that the gauge measures the thickness of the strip and different points along the longitudinal lines of the strip. The measurements of the thickness of the strip at the different points are interpreted into profile data. This profile data can be either displayed or used by a mill computer to control the processing of the strip.

Abstract: A method and apparatus for measuring simultaneously the thickness and the composition of a coating on a metal substrate. A first beam of radiation that produces a primary beam of photons is directed substantially perpendicularly to the surface of the coating. A first detector is positioned substantially perpendicularly to the surface of the coating to receive a first fluoresced beam. The photons having a first energy level representing a higher concentration element of the coating are selected. A first electrical signal is provided that is a function of the intensity of the photons having the first energy level. A second beam of radiation producing a second primary beam of photons is directed at an acute angle to the surface of the coating. A second detector is positioned substantially perpendicularly to the surface of the coating to receive a second fluoresced beam. The photons having a second energy level representing a lower concentration element of the coating are selected.

Abstract: This invention applies to thickness gauges consisting of a radiation source producing a beam aimed at a detector. Whenever a material to be gauged obstructs the radiation beam, the intensity received by the detector (detector output) varies and said variation can be translated into a thickness measurement. Standards are used for calibration. This invention provides computer means and methods that provide better measurements by using a function relating the thickness to the detector output in a large range and independently of random inaccuracies of the standards.