Fire damp-protected lighting of dials of underground machinery - uses optical fibre waveguides to conduct light from central source to scales without or with scattering

摘要

A central light source (2) fully protected against risk of explosion in the underground atmos. is coupled by glass, plastic or polymer fibre lightguides (3a-3d) to the dials (6) of instruments on underground machines and vehicles. Two instances are distinguished: one where the light is distrubuted by a scattering head (5) over the scale (4) of the dial (6), and the other where the light is not scattered but aimed directly from the lightguide (3) on to the scale (4). ADVANTAGE - Normal dials are used e.g. on overground vehicular dashboards can be read without difficulty in the mine environment.