What instruments and methods are used for underground pipeline detection?

Underground pipeline detection technology is a technology for detecting and mapping various pipelines under the city. Detection is to investigate the existing underground pipelines on site and use different detection methods to detect the buried location and depth of various pipelines. Mapping is to determine underground pipeline measurements and pipeline maps, including construction measurements and as-built measurements for new pipelines. The main methods of underground pipeline detection are: direct method, clamping method, induction method, geo-radar method, etc.

1、Direct method

The direct method connects the transmitter of the underground pipeline detector to one end of the pipeline outcrop point and the other end to the vertical pipeline to the ground, the transmitter applies a specific frequency of alternating current through the connection to the pipeline, the current flows along the pipeline in the direction of its extension and returns to the ground through the ground, forming a circuit. At the same time, an alternating electromagnetic field of the same frequency is formed around the pipe, and then the ground above the pipe is scanned with a receiver to receive this alternating electromagnetic field to locate and fix the depth of the pipe. The method is characterized by strong output signal from the transmitter, good anti-interference performance, is one of the main methods used.

2、Clamp method

In the case of measuring the pipeline, the clamp method can not be directly connected to the transmitter signal output, you can use the clamp method. When working, the underground pipe line detector transmitter signal is applied to the clamp, and then the clamp is installed on the metal pipe being measured. Underground pipe line detector clamp is equivalent to the primary coil, the pipe and grounding to form a circuit equivalent to the secondary coil. When the AC current output from the transmitter flows in the primary winding, the toroidal magnetic field passes through the pipeline circuit and generates an induced secondary current in the pipeline. In the dense area of the pipeline detection, the clamp method is a small and effective cross-impact method, generally applicable to thin-walled pipeline diameter.

3、Induction method

Induction method will be placed above the target pipeline transmitter, underground pipeline detector transmitter coil emits a specific frequency of alternating electromagnetic field, the alternating electromagnetic field in the pipeline will be coupled with the same frequency of alternating current, current flow along the pipeline in the direction of its extension, while forming the same frequency of alternating electromagnetic field around the pipeline, and then use the receiver to scan above the pipeline to receive this level field, the pipeline is positioned and fixed depth.

4、Geo-radar method

The geo-radar method uses a pulsed radar system that continuously transmits video pulses with a pulse width of several milliseconds into the ground and receives the reflected electromagnetic pulse signal.

Cautions.

(1) The direct connection method must be disconnected if it is a power cable, and then operated. (2) If the pipe corrosion is serious, it needs to be polished with a file. Then connect with strong magnetic adsorption. (3) If the grounding point soil is relatively dry can pour some water to improve the grounding effect. If the conditions allow the grounding point shall not be less than 5 meters from the transmitter. (4) induction method can only choose 65KHz and 83KHz two kinds of frequency, no direct connection signal output line or clamp inserted, the instrument automatically select the induction mode, induction mode frequency can only choose 65KHz and 83KHz two kinds; clamp method can only choose 33KHz a frequency, when the clamp access to the instrument, the instrument automatically choose 33KHz frequency, do not need to artificially select Clamp the use of frequency.

Puchi Water Environment Research Institute is a professional institution engaged in the research and development of geological exploration equipment. It is mainly dedicated to the research and development, production, sales and service of pipeline detector, physical prospecting water finder, pipeline leak detector, dike pipe surge detector, pressure pipeline leakage automatic analyzer, in-well imager, cavity detector, prospector, pipeline cleaner, thermal imager.