Light Pipes Lighting System

In this project, a new style of lighting system was developed for use on underground machinery, such as longwall shearers, continuous miners and mobile vehicles.

A 'light engine' constructed from multiple, high power light-emitting diodes was developed and mounted within a compact flameproof enclosure. A multi-lens assembly was designed to focus and couple the light into individual elements of a bundle of 14mm diameter optic-fibre 'light-pipes'. Light is transmitted internally along the light pipes by total internal reflection from the light engine, located within the enclosure, to the exterior, via a potted flameproof gland assembly. The light-emitting end of the light pipes system can be located up to 10 metres from the flameproof enclosure housing the light engine. Applications of the lighting system are: close quarter illumination of a longwall shearer cutter drum; illumination of the cutting zone on a continuous miner; and as an extremely robust head light for mobile rubber-tyred mining equipment.

A major advantage of this new light pipe system is that the light-emitting end of the light pipe does not contain electrical components and can, thus, sustain catastrophic damage without introducing a safety risk. The device is much safer than current underground lighting products and, unlike existing lighting products, a damaged light pipe does not trigger formal incident reporting procedures.

Benefits of the 'light pipes' lighting system are:

· improved illumination when compared with existing Ex d mounted incandescent lights;

· enhanced visibility for machine operators in extremely harsh environments, for example, close to the cutter drum on a longwall shearer;

· the elimination of reportable incidents due to damaged lighting equipment as exists for flameproof electric powered lights;

· the illuminated end operates at a few degrees above ambient and is not subject to failure by heat shock induced by the sudden application of a cold water spray;

· the light pipe will continue to operate effectively even after sustaining considerable physical damage;

· a damaged light pipe can be quickly and easily repaired to original condition by underground staff using simple hand-held tools and/or replacement components.

The resultant light pipes lighting system is able to provide a safe and extremely robust light which can be used in hostile environments such as longwall shearers, continuous mining machines and  underground mobile vehicles.