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monitoring room and pumped to the ground by long-distance bundle tube for chromatographic
analysis. Because of the long distance between bundles and pipes, many pipe joints, air leakage
often occurs, and the measurement error is large, the maintenance cost is high. More importantly, it is impossible to locate the fire source effectively. In this paper, distributed optical fiber
temperature measurement technology is proposed to monitor coal mine goaf ignition, and the
instrument adopts intrinsically safe design, and has outstanding advantages of safety, convenience and other advantages, and has been successfully applied in the field. The environment of
goaf is bad, so the construction and protection of optical cable is particularly important.
2 COAL MINE FIRE MONITORING
Coal mine fires are mainly divided into internal fires and external fires. Internal fires are
mainly caused by coal self-ignition and external fires are mainly caused by equipment or
electric cable short circuits. Distributed optical fiber temperature measurement technology
offers advantages of inherent safety, wide monitoring range, accurate positioning in solving
mine fires.
2.1 Coal mine self-ignition
2.1.1 Scheme
As shown in the figure, the temperature-sensitive optic cable is laid along two lanes of the
roadway, and the end of the cable is connected to the demodulator. The demodulator is
installed in the nearest substation. The demodulator is responsible for optical signal output
and detection, temperature demodulation and data transmission. It is transmitted to the
ground server which includes a network distribution software via the ring network switch [3].
2.1.2 Protection of optical cable
Due to the harsh environment of the goaf, the selection and protection of the cable is very
important. The armored and high-strength flame-retardant fiber optic cable is selected. The
protection of the fiber optic cable is implemented by buried laying, steel pipe protection and
spring structure stainless steel. Connect the spring tube at the joint to prevent the cable from
being deformed by extrusion. According to the specific actual conditions of the coal mine, it can
also be laid along the supply air supply pipeline and the gas drainage pipeline, and laid on the
side of the pipeline. Once the coal mine roof collapses, the support of the pipeline can be used
for protection.
2.2 Fire monitoring of belt conveyor and cable
The distance between the belt conveyor and the cable is wide, and the traditional point type
monitoring is difficult to implement. The distributed optical fiber temperature measurement
technology is specially suitable for this occasion. The fire monitoring of the belt conveyor
and the cable focuses on solving the laying problem of the optical cable, and can be along the
belt conveyor. Cables are laid along the cable or cable surface for temperature sensing. The
belt conveyor idler is a hot spot. It is recommended to wind the cable at the roller bearing and
increase the protection of the cable. The monitoring effect is better [4].
3 HOST DISIGN
3.1 Hardware design
An embedded, high-performance, low-power processor is used as the control core. In view of
the limitations of current intrinsically safe power performance specifications, two intrinsically
safe power supplies are used for whole system’s power supply [2]. One power load includes pulse
monitoring room and pumped to the ground by long-distance bundle tube for chromatographic
analysis. Because of the long distance between bundles and pipes, many pipe joints, air leakage
often occurs, and the measurement error is large, the maintenance cost is high. More importantly, it is impossible to locate the fire source effectively. In this paper, distributed optical fiber
temperature measurement technology is proposed to monitor coal mine goaf ignition, and the
instrument adopts intrinsically safe design, and has outstanding advantages of safety, convenience and other advantages, and has been successfully applied in the field. The environment of
goaf is bad, so the construction and protection of optical cable is particularly important.
2 COAL MINE FIRE MONITORING
Coal mine fires are mainly divided into internal fires and external fires. Internal fires are
mainly caused by coal self-ignition and external fires are mainly caused by equipment or
electric cable short circuits. Distributed optical fiber temperature measurement technology
offers advantages of inherent safety, wide monitoring range, accurate positioning in solving
mine fires.
2.1 Coal mine self-ignition
2.1.1 Scheme
As shown in the figure, the temperature-sensitive optic cable is laid along two lanes of the
roadway, and the end of the cable is connected to the demodulator. The demodulator is
installed in the nearest substation. The demodulator is responsible for optical signal output
and detection, temperature demodulation and data transmission. It is transmitted to the
ground server which includes a network distribution software via the ring network switch [3].
2.1.2 Protection of optical cable
Due to the harsh environment of the goaf, the selection and protection of the cable is very
important. The armored and high-strength flame-retardant fiber optic cable is selected. The
protection of the fiber optic cable is implemented by buried laying, steel pipe protection and
spring structure stainless steel. Connect the spring tube at the joint to prevent the cable from
being deformed by extrusion. According to the specific actual conditions of the coal mine, it can
also be laid along the supply air supply pipeline and the gas drainage pipeline, and laid on the
side of the pipeline. Once the coal mine roof collapses, the support of the pipeline can be used
for protection.
2.2 Fire monitoring of belt conveyor and cable
The distance between the belt conveyor and the cable is wide, and the traditional point type
monitoring is difficult to implement. The distributed optical fiber temperature measurement
technology is specially suitable for this occasion. The fire monitoring of the belt conveyor
and the cable focuses on solving the laying problem of the optical cable, and can be along the
belt conveyor. Cables are laid along the cable or cable surface for temperature sensing. The
belt conveyor idler is a hot spot. It is recommended to wind the cable at the roller bearing and
increase the protection of the cable. The monitoring effect is better [4].
3 HOST DISIGN
3.1 Hardware design
An embedded, high-performance, low-power processor is used as the control core. In view of
the limitations of current intrinsically safe power performance specifications, two intrinsically
safe power supplies are used for whole system’s power supply [2]. One power load includes pulse