With the continuous development of China's coal industry, a prominent problem has emerged, which is that during the transportation of coal on conveyor belts, the temperature of the conveyor belt directly affects production safety. Real time monitoring of conveyor belts has become one of the necessary means to ensure coal safety production. Judging the fire situation of conveyor belts based on temperature changes is the most effective monitoring method. Due to the requirement for accurate quantification and positioning of environmental temperature changes on conveyor belts. Based on the characteristics of this project, we suggest using a DTS distributed fiber optic temperature monitoring system for the monitoring of the coal conveyor belt in the project. The DTS distributed fiber optic temperature monitoring system utilizes fiber optic temperature sensing signals and transmission signals, adopts advanced OTDR technology and Raman scattering light's temperature sensitive characteristics, detects temperature changes along different positions of the fiber optic, and achieves accurate measurement.

1. The significance of temperature monitoring for coal conveyor belts

  Quasi intelligent sensing Monitoring the temperature of the coal conveyor belt can have the following benefits:

  l Delaying investment expenses;

  l Can achieve periodic emergency assessment;

  l Drive external alarms or other emergency systems;

  l Discover hotspots and other environmental anomalies。

2、Characteristics of coal conveyor belt fires

  a、Spread quickly and the fire is fierce Coal itself is a flammable substance. Due to the large number of coal conveyor belts and the use of overhead dense laying, some are still in environments with high temperatures or staggered arrangements. Therefore, once these places catch fire, the fire becomes particularly fierce and the harm is also particularly significant。

  b、Difficulty in controlling and rescuing coal transportation system fires。

3、Application of temperature sensing optical fiber laying method for coal conveyor belt

  Under the condition that the width of the belt conveyor device does not exceed 3 meters, a temperature sensing optical fiber with the same length as the conveyor belt can be used for protection. The temperature sensing optical fiber should be directly fixed to an accessory located no more than 30cm below the center of the conveyor belt. The accessory can be a suspension wire (the purpose of the suspension wire is to provide a support component), or it can be used with existing fixtures on site. Use a tightening bolt every 50-100m to fix the suspension wire. To prevent the falling of temperature sensing optical fibers, a fastener should be used every 1-5m to clamp the temperature sensing optical fibers and suspension cables tightly. The material of the suspension cable should be non embroidered steel wire, and its single length should not exceed 150m (galvanized steel wire can also be used to replace it when conditions are not available).

  △ Another recommended method for installing conveyor belts is to install temperature sensing optical fibers on both sides close to the conveyor belt. The temperature sensing optical fibers can be connected through differential heat plates and ball bearings to detect overheating caused by bearing friction and coal powder accumulation. The general design and installation principle is to determine based on on-site conditions without affecting normal operation and maintenance。

  The length of the temperature sensing optical fiber is determined by the following formula: length of the temperature sensing optical fiber=(distance from the nearest end of the detection area to the control room+length of the conveyor belt)×1.15