Method of measuring bending of an elongate vertically oriented channel

A method of measuring bending of an extended vertically directed channel, including placing at least one fibre-optic sensor fixed at the end of a flexible hollow carrier rod inside the channel, supplying a light signal via fibre-optic lines connected to the sensor, recording reflected light signals using a photoreceiver connected to the fibre-optic lines, and determining bending of the channel on the basis of analyzing the parameters of the light signal using a computer connected to the photoreceiver, characterized in equipping a fibre-optic sensor with a gravity pendulum that is suspended for angular motion at the lower end of the fibre-optic sensor;

• passing a flexible hollow carrier rod with the fibre-optic sensor along the channel and using a photoreceiver and a computer to register the shift of an interference pattern of a reflected light signal in a gas gap between the upper end face of the gravity pendulum and the lower end face of fibre-optic lines connected to the photoreceiver and fastened to the sensor, said gas gap varying during the passage of the fibre-optic sensor as a result of the angular motion of the gravity pendulum away from the axis of the bowed extended vertically directed channel;
• recording, on the basis of the registered shifts of the interference pattern of the reflected light signal, profilograms of the variations of the gas gap for each fibre-optic line;
• and calculating, on the basis of the obtained gas gap profilograms, the magnitude and direction of bending of the extended vertically directed channel from the vertical axis.