塑料上附金属线。

由于微波物理探地雷达无法探测到塑料管道，对于今后维修、其他施工造成障碍，所以在塑料管道上附金属线，提供响应标志。

示踪线的测试原理

铜包钢是由钢芯线和紧密包覆其外的铜层构成金属芯，最外侧为PE防腐层，铜起到传导弱电信号的作用，钢丝则起到支撑作用。铜芯电线一般由最内层的铜芯线、中间层的绝缘包皮和最外层的保护外皮组成。铜包铝由铝芯线和紧密包覆其外的铜层构成金属芯，最外层为PE防腐层。

由于钢质燃气管道最外层的防腐层为具有绝缘、防腐性能的塑料层或涂层，与铜包钢、铜芯电线、铜包铝等最外层也为具有绝缘、防腐性能的塑料层结构相似。因此，我们将两者等效，通过采用PCM管道电流衰减率法[1]，对示踪线防腐层平均绝缘质量进行检测。检测原理是向示踪线施加某一频率的电流信号，电流由示踪线向远方传递时会逐渐衰减。其衰减大小与示踪线的塑料层的绝缘电阻率有关，示踪线塑料层的平均绝缘电阻率越高，电流衰减就越慢，反之则衰减越快。

更多示踪线的资讯与订购，可联系华德线缆！

Metal wires are attached to the plastic.

Because the microwave physical ground penetrating radar can not detect the plastic pipe, it will cause obstacles for future maintenance and other construction, so metal wires are attached to the plastic pipe to provide response signs.

Testing principle of tracer line

Copper clad steel is a metal core composed of steel core wire and closely wrapped copper layer. The outermost layer is PE anticorrosive layer. Copper plays the role of conducting weak current signal, while steel wire plays the role of supporting. The copper core wire is generally composed of the innermost copper core wire, the insulating sheath of the middle layer and the outermost protective sheath. The copper-clad aluminum consists of aluminum core wire and copper layer, and the outermost layer is PE anti-corrosion layer.

As the outermost anti-corrosion layer of steel gas pipeline is a plastic layer or coating with insulation and anti-corrosion performance, the structure is similar to that of copper-clad steel, copper core wire, copper-clad aluminum and other outermost plastic layers with insulation and anti-corrosion performance. Therefore, we use PCM pipeline current decay rate method to test the average insulation quality of tracer line anticorrosive coating. The detection principle is to apply a certain frequency current signal to the tracer line, and the current will gradually attenuate when it is transmitted from the tracer line to the distance. The attenuation is related to the insulation resistivity of the plastic layer of the tracer line. The higher the average insulation resistivity of the plastic layer of the tracer line is, the slower the current attenuation is, and vice versa.