The movement of materials for mining is of critical importance to any operation and conveyors continue to showcase their advantages. The need to protect them against fire is equally as important.
Simply put, conveyor systems are the ideal solution to transport managed sized material from one processing point to another, such as an underground mining operation to a processing refinery or from a silo to a packing plant. The reliance on manpower is minimised and reliability is maximised with the use of conveyor systems, provided protection measures are taken to reduce the chance of mechanical or electrical failure.
A key protection area for consideration is how to handle the issue of a conveyor belt system fire. Methods for the protection of conveyor belt systems have improved immeasurably in some areas but have largely stagnated in others.
The essential philosophy behind conveyor belt fire protection revolves around the preservation of the conveyor belt system structure. A fire can weaken the metal structure, and in some cases, to a point of collapse.
Detection methods have evolved since the 1940s thermocouple hoods. The use of spark and ember detectors has been popular in the past, but has largely proved ineffectual. They often cause false alarms from reflective light or solar emissions. Also the monitored bandwidth that would result in an alarm is quite narrow, and early stage combustion cannot always be detected.
The sources of conveyor belt fires result from two areas, either static heat build-up from friction caused by belt movement over a jammed idler, for example, or moving fire on the belt itself.
For early detection of static type fires, linear heat detection cable has proven to be reliable when correctly installed. It can also be placed between the belt and return belt if practical.
Combined together, linear heat detection cable and thermal energy black body fire detectors offer the most comprehensive solution to detecting fires on conveyor belt systems. If installed properly, they can be integrated into a water extinguishing system, either a sprinkler bulb type or a water-spray type.