| 摘要 |
An exit sign for use in hazardous atmospheres including an explosion-proof housing and a sign panel with indicia thereon. The housing prevents the ignition of gas or vapor surrounding the enclosure due to sparks, flashes or an explosion of the gas or vapor within the enclosure by providing an ample heat sink surface along any flame path to cool gases escaping from the housing. The sign panel preferably includes one or more transparent sheets which are edge lit from a light source contained in the explosion-proof housing that shines through a window in the housing into the top edge of the sign panel to illuminate the face(s) and the indicia thereon. The light source utilizes a number of long life light emitting diodes. The exit sign preferably includes a sealed maintenance-fee rechargeable battery for powering the light source when externally supplied power to the exit sign is absent. |
