System employing plural time-spaced average computations for measuring a second variable characteristic imparted to a material initially having a first variable characteristic

摘要

1,048,970. Automatic thickness control. INDUSTRIAL NUCLEONICS CORPORATION. Aug. 4, 1964 [July 16, 1963],No. 30571/64. Heading G3R. [Also in Division G1] The thickness of a moving strip of material is measured electrically before and after a coating is applied, the first measurement being stored for the time taken by the strip to reach the second measuring location before a comparison is made, whereby the thickness of the coating is ascertained and used to control the coating process. As shown (Fig. 1), the thickness of a strip 10 is measured by gauge 14 before entering a coating machine 12, and by a gauge 24 after the coating machine, the gauges being mechanically connected to drives 20, 30 which cause them to traverse across the width of the strip 10. Each gauge 14, 24 is connected to a meter 18, 26 feeding thickness signals to computers 34, 36 where the signals are integrated over a period to obtain their average values, and the difference derived in unit 80. The system is controlled by a programmer 42 in conjunction with an odometer 46, 48 measuring the length of the strip 10 fed into the coater 12, causing gauge 24 and its associated units to be delayed by the time necessary to allow the strip 10 to move from gauge 14 to gauge 24. The difference signal from unit 80, indicative of the thickness of coating on strip 10, is fed to a meter 90 and to controlling mechanism 92 to control the coater 12 automatically. The programmer 42 arranges for the above to be cyclically repeated, when gauge 24 returns to its initial position.