Tunnel project fire alarm system linear fiber optic temperature sensing fire detection alarm

Fiber optic temperature sensor, Intelligent monitoring system, Distributed fiber optic manufacturer in China

Most highway tunnel fire alarm systems are designed with cable type temperature sensors, and cable type temperature sensors that transmit optical signals are selected according to the environmental requirements of the tunnel. Practice has proven that cable type temperature sensors for optical signals have significant advantages over other types of cable type temperature sensors, such as temperature sensing cables, in terms of electromagnetic interference, signal transmission distance, corrosion resistance, and reliability such as false alarms and false alarms. Currently, two commonly used cable type temperature sensors in engineering are fiber optic gratings and temperature sensing fibers.
Use dual channels in the substation at one end of the tunnel, with a distributed fiber optic detection host of 4km per channel, corresponding to a temperature sensing fiber optic with a detection distance of 4km, and a fiber optic terminal box at the endpoint; Use dual channels in the substation at the other end of the tunnel, with a distributed fiber optic detection host of 2KM per channel, corresponding to a temperature sensing fiber optic with a detection distance of 600m. The endpoint position is consistent with the 4km temperature sensing fiber optic from the opposite end, and connected to the fiber optic terminal box.
Both distributed fiber optic detection hosts are connected to corresponding fire alarm control devices. The two fire alarm controllers can be connected to the local upper computer or uploaded to the central control mechanism, or connected to one of the fire alarm controllers using a data optical transceiver and configured with software to achieve secondary control. The latter is commonly used in engineering to improve system integration. If the capacity of the fire alarm controller is sufficient, it is also possible to directly connect the remote distributed fiber optic detection host with the fire alarm controller using an optical transceiver, thereby saving one fire alarm controller.
If a tunnel substation is only set up at one end of the tunnel, another set of distributed fiber optic detection host and fire alarm controller can be placed in the equipment cabinet inside the tunnel.
This diagram is also applicable to tunnel fire detection with a detection distance of 4km to 8km. The length of the temperature sensing fiber and the detection distance of each channel of the distributed fiber detection host are selected according to actual needs
If dual channels are selected, distributed fiber optic detection hosts with a length of 5km or more per channel are used.
Differences. As the detection distance increases, the structure of temperature sensing fiber optic detection systems tends to become more complex. If only a tunnel substation is set up at the end of the tunnel, corresponding equipment needs to be placed inside the tunnel.

The linear fiber optic temperature fire detection alarm adopts dual channels, with 3 distributed fiber optic detection hosts located at 4km per channel. At the tunnel end substation, the distributed fiber optic detection host is connected to a temperature sensing fiber optic cable with a detection distance of 4km to two holes. The end point is connected to a fiber optic terminal box, and the temperature sensing fiber optic cable is led out from the distributed fiber optic detection host in each hole of the substation as shown in Figure 5. One end is aligned with the end point of the temperature sensing fiber optic cable from the tunnel end, and the other end is connected to the hole. The end point is connected to the fiber optic terminal box.
The distributed fiber optic detection host is connected to the corresponding fire alarm controller, and a network of fire alarm controllers is constructed. The data optical terminal is connected in pairs and software settings are made, so that all three fire alarm controllers can display the fire alarm situation of the entire tunnel.
If a tunnel substation is only set up at one end of the tunnel, the other two sets of distributed fiber optic detection hosts and fire alarm controllers can be placed in the equipment cabinet inside the tunnel.
If a dual channel distributed fiber optic detection host with a distance of 6km or more per channel is selected, and the differential detection distance increases to 8km or more, the structure of the temperature sensing fiber optic detection system is complex, and the equipment placement is scattered.