Glass Protection Device - Videotec EXPT Série Manuel D'instructions

4.1 Glass protection device

The pan & tilt unit series EXPT can be equipped with the glass protection device, installed on the front opening
of the camera housing. It consists of a connection flange with the housing, a closing flange and an explosion-
proof central body containing a rugged and transparent glass, a direct current motor power supplied at 24 Vdc,
two windings and a transparent Mylar film, installed just in front of the glass. The motor drives, through four
pinions with gear rim, the winding for recovering the dirty Mylar film, while at the same time the other winding
installed on the opposite side releases the clean film. The motor is remotely controlled through a two wires on-
off contact (common and + 24Vdc).
The control unit of the glass protection device is provided by the customer!
The transparent Mylar film allows to obtain about 350 shifting steps. When the film is dirty, the operator will
activate the motor shifting the film until to obtain a clean camera picture (the step for allowing the completely
shift of the dirty film is about 50 cm). The end of the Mylar film will directly indicated to the operator, through
suitable marks printed on the last 50cm of the film.
If requested, the film shifting could be also automatically time-controlled, through a suitable control system (not
included in the supply).
To replace the Mylar film, take out the windings and replace the dirty film with a clean one.
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