Rail transit field

working principle

The temperature sensor on the pipeline inside the tunnel sends the sensed temperature signal to the temperature control meter in the intelligent temperature control distribution box through the signal cable. The temperature control table compares the received temperature with the set temperature, the current temperature. When the temperature is higher than the set temperature, the electric heating will not work. When the current temperature is lower than the set temperature, the electric heating starts to work. In order to avoid frequent starting, a hysteresis is generally set. The distribution box can also be remotely communicated with the central control room. Or DCS system connection, you can observe and control the start and stop of the electric heating cable at the far end.

Construction installation

The electric heat tracing of the tunnel fire-fighting pipeline is similar to that of the ordinary pipeline installation. Due to the harsh environment of the tunnel fire-fighting pipeline, the tunnel fire-fighting construction must be stricter, and the quality and quantity are completed.

Rail transit electric heat tracing system

The special electric heating system for rail transit is an intelligently controlled electric heat tracing system specially developed for the subway, railway and other rail transit fields. It is mainly composed of the heating cable for rail transit and the electric heating control box for rail transit. Part of the composition.

1、Heating cable for rail transit

The heating cable for rail transit adopts the series double-conductor and double-wire type structure, which belongs to the constant power heating cable and is the mainstream product in the Xinhuaning brand series. It is mainly composed of an outer sheath, a grounding wire, a shielding layer, an inner conductor and an inner insulation, and the cold and hot parts are welded together by means of an implicit joint.

The material of the outer sheath is generally blue polyvinyl chloride, rubber or fluoroplastic. The material of the grounding wire is generally tinned copper wire. The shielding layer is generally aluminum foil or metal woven mesh. The inner conductor material is generally metal alloy wire or copper. Wire, the inner insulation material is generally XLPE, rubber and fluorine material outer diameter, power supply voltage, cold wire length can be customized, good bending performance, the minimum bending diameter is 5 times the outer diameter.

2、Special electric heating control box for rail transit

The special electric heat tracing control box for rail transit is used to control the heating cable laid on the pipeline, and can control the heating cable of 1 to 6 pipes at the same time. By comparing the temperature of the pipeline detection with the parameters set by the user on the dedicated controller in the control box, thereby controlling the working state of the heating cable, preventing the occurrence of problems of pipeline icing, cracking of the pipeline and the occurrence of ultra-high temperature, each The pipeline adopts a dual-loop control mode with one standby and one standby, and automatically switches to the standby loop when the main loop heating cable is broken and leaked, which greatly improves the reliability and safety of the electric heating system.

The control box can also realize the automatic alarm function of the accident; including ultra-high temperature alarm (high temperature or low temperature), leakage alarm, cable break alarm and sensor fault alarm. The above alarm is transmitted to the central control room through RS485 communication, which facilitates centralized management and improves the use efficiency.

The control box is equipped with a constant temperature drying device, which can maintain the good working environment of the electrical components in the control box and prolong the service life of the control box. The control box and the LED display can visually see the working state of the electric heating, the fault state, and the real-time temperature. Easy to manage users.

The dedicated controller in the control box is reserved for expansion space at the time of design, and some functions can be added as needed without re-development.