The belt conveyor serves as the main coal transport equipment in a coal mine and its safe operation is the lifeline of safety in coal mine production. However, traditionally, monitoring for ignition and for roller faults along the belt conveyor is problematic and so this paper puts forward an approach using radial grating vibration sensing technology for both belt conveyor roller vibration monitoring. This can then be used to predict the fault state in the roller and its position, using distributed optical fiber temperature measurement technology which can be used for ‘hot spot monitoring’. This enables better fire prevention along the belt conveyor, which plays a positive and effective role in better mine safety.
Built on a design developed from an advanced mathematical model, a practical fiber optic sensor, which is an analog of the familiar ‘hot-wire’ wind velocity monitor is developed, as an intrinsically-safe sensor device for coal mining monitoring applications. The underpinning optical fiber-based principle used is the shift in the center wavelength of a Fiber Bragg Grating which is cooled by the gas flowing over it and the device sensitivity found was determined to be ~1370pm per unit m/s wind velocity (in the range of 0-0.57 m/s), ~109pm per unit m/s in the range 0.57-2.26 m/s and ~33pm per unit m/s in the range of 2.26-5.66 m/s. In this paper, the factors that influence the device response time, such as the sensor probe surface heat transfer coefficient, wind (gas) velocity and pump power have been investigated in the laboratory. It was found that the greater the surface dissipation factor of the sensor, the shorter the response time, furthermore, the response time was observed to decrease as the wind velocity increased. A method of further shortening sensor response time using wind speed variation slope is proposed.