'Helium hood method' long-distance pipeline leakage point troubleshooting and positioning device and troubleshooting method

The invention belongs to the nondestructive testing technology, and particularly relates to a 'helium hood method' long-distance pipeline leakage point troubleshooting and positioning device and troubleshooting method. The device comprises a flow supply and control plate A arranged at the upstream of a detected pipeline, and a helium hood and a helium applying plate B connected with the detected pipeline. The helium hood and helium applying plate B is composed of a helium hood, a helium concentration detector, a pressure reducing valve, a helium supply switch, a helium pressure stabilizing tank, a helium cylinder and a pressure gauge. The method comprises the following steps of: purging the pipeline to remove residual working gas, installing the helium hood on the detected pipe section, inflating the detected pipe with helium, checking leakage points, taking flange opening positions at the two ends of an inlet and an outlet of the pipeline as detection interfaces, applying a long-distance helium hood to the p