CONTINUOUS GAGING SYSTEM

In strip mills and wire mills producing rolled or drawn material at high traverse speed and in very great lengths, special gages are used to monitor the thickness and/or width of the manufactured material as it exits from the processing equipment. Such gages are usually equipped with mechanical contacts, typically floating arm mounted rolls, acting on fast response (linear variable differential transformer) (LVDT) transducers. The detected variations from the preset zero size are shown either on an analog meter or on a digital display. Gage setting accuracy is on the order of 0.0001 inch.

Advanced systems have push-button gage zeroing from the operator’s station, which can be operated while the material rolling is in progress, and serves to eliminate temperature-related fluctuations. Generally oversize–undersize limit warning lights are also provided either on the meter panel or as a separate unit for complementing the basic gaging system. The light signal units of continuous gages frequently comprise time-delay relays, with timing range adjustable, for example, from 0.1 to 10 seconds. That capability’s purpose is to prevent the control from responding to conditions such as dirt or welds, which could produce false oversize signals.

The more recently developed computerized continuous gaging systems also have interchangeable English unit/metric capability, an analog meter for continuous monitoring of deviation errors from the set nominal size, plus direct digital display to the absolute value of strip thickness; that latter display is operated on command.