Patent ID: 8760669

Claim:
A detector device for contact support of a flexible continuous web being monitored and that is moving in a downstream machine direction, which comprises: (a) a first mounting head disposed on a first side of the moving web; (b) a second mounting head disposed on a second side of the moving web and which comprises a body haying an operative surface facing the second side of the web wherein the operative surface defines a measurement surface with a perimeter and has a web entry end and a web exit end that is downstream from the web entry end; (c) a displacement sensor that is positioned in the second mounting head to determine a distance from the displacement sensor to a reference surface on the first mounting head; (d) an optical sensor, positioned in the first mounting head, for measuring the distance from the optical sensor to the first side of the moving web at the measurement surface wherein the optical sensor is thermally isolated from the displacement sensor; (e) means for positioning the moving web such that the second side of the web comes into contact with the measurement surface as the web passes over the measurement surface, which comprises a first channel that is disposed on the operative surface and which encircles at least part of the perimeter of the measurement surface wherein sub-ambient pressure from the first channel holds the moving web against the measurement surface and a second channel that is disposed on the operative surface and which has an arch-shaped configuration that partially encircles the first channel wherein the second channel comprises an indentation in the operative surface and which has a proximal end located upstream of the measurement surface and first and second distal ends located downstream of the measurement surface with the first distal end having a first gas vacuum port and the second distal end having a second gas vacuum port; and (f) means for regulating the temperatures of the first mounting head and of the second mounting head.