Variable reluctance transducer for sensing and excitation of transversal oscillations of string sensor measuring string

摘要

In the present invention, there is disclosed a variable reluctance transducer for sensing and excitation of transversal oscillations of the measuring string (14) of a string sensor placed within a protective tube (13). The variable reluctance transducer of the present invention comprises a cylindrical permanent magnet (2) with a coil (1) and a magnetically conducting external outer C-shaped yoke (3) disposed outside the coil. The external yoke (3) is formed by a magnetically conducting flexible band with the width greater than diameter of the permanent magnet and thinner than the diameter of the coil (1) wherein both ends of said magnetically conducting flexible band are provided with end bend (4) to butt position with the protective tube (13) in a plane parallel to the measuring string (14). Mirror symmetry of the invented variable reluctance transducer makes it possible to divide the double transducer into two single-coil transducer by a cross section in a mirror symmetry plane (16) or to form a socket by only performing a notch groove in this mirror symmetry plane (16) for additional magnetic screening.