Device and method for collecting water sample at specified depth in drill hole

The invention relates to a device and method for collecting a water sample at a specified depth in a drill hole, and belongs to the technical field of water sample collection. The problems of low sampling efficiency and poor working reliability of an existing collecting device are solved. The collecting device comprises a mounting frame, a collecting assembly, a take-up and pay-off mechanism and a controller, the collecting assembly comprises a collecting cylinder with a plurality of collecting chambers, each collecting chamber is provided with an extraction opening, a sample inlet and a sample outlet, and the sample inlet is provided with a sample inlet switch assembly; a liquid level sensor is arranged on the collecting cylinder; a winding roller of the take-up and pay-off mechanism is rotationally arranged on the mounting frame, the first end of a pull wire is wound around the winding roller, the second end of the pull wire penetrates through a wire guiding assembly to be connected with the collecting asse