APPARATUS AND METHOD OF MEASURING THE INNER DIAMETER OF A TUBE ALONG THE RESPECTIVE PRODUCTION LINE

The present invention concerns an apparatus and a respective optical detection method (1) for the non-contact dimensional measuring of the inner diameter of a tube (T) along a production line, wherein the apparatus comprises at least one thickness measure sensor (4) of the optical type and at least one diameter measure sensor (5, 5') for measuring the outer diameter (D) of the tube (T). Each diameter measure sensor and at least one respective thickness measure sensor are constrained to a supporting body (2) so that to be radially oriented with respect to the geometric axis (X) of the tube (T) and so that said at least one thickness measure sensor measures the thickness at a tube section belonging to the outer diameter (D) of the tube detected by the respective diameter measure sensor. The thickness and diameter measure sensors are synchronized for measuring simultaneously and the inner diameter (d) of the tube is calculated as the difference between the outer diameter and the thickness of the tube detected.