Coil apparatus of an oscillation sensor of a measuring transducer, measuring transducer of a measuring device and measuring device

A measuring transducer of a measuring device for registering a mass flow or a density of a medium flowing through at least one measuring tube of the measuring transducer, comprising:

• the at least one measuring tube having an inlet and an outlet and adapted to convey the medium between inlet and outlet;
• at least one exciter, which is adapted to excite the at least one measuring tube to execute oscillations;
• and at least two sensors, which are adapted to register deflections of oscillations of at least one measuring tube,
• wherein the exciter as well as the sensors have, in each case, a coil apparatus and, in each case, a magnet apparatus, wherein the magnet apparatuses are movable relative to their coil apparatuses, and wherein the magnet apparatus and the coil apparatus of an exciter, or sensor, as the case may be, interact by means of magnetic fields,
• wherein the measuring transducer has a support body, which is adapted to hold the at least one measuring tube,
• wherein the sensors have, in each case, a coil apparatus, wherein the coil apparatus includes:
• a circuit board having at least one circuit board layer, wherein each circuit board layer has a first face and second face planparallel to the first face,
• at least one coil adapted for registering or producing a time varying magnetic field, wherein the coil is embodied at least sectionally by means of an electrically conductive trace,
• wherein the coil is arranged on the first face or second face of a circuit board layer,
• wherein the at least one coil has, in each case, a first coil end and, in each case, a second coil end,
• wherein an at least one, first coil end as well as at least one, second coil end are connected, in each case, with a contact therefor,
• wherein the at least one coil has, in each case, a winding region and a central region lacking turns of a winding, wherein the central region of a coil has a rectangular shape with oppositely lying, first sides and with oppositely lying, second sides, wherein the first sides have a first side length, and wherein the second sides have, in each case, a second side length,
• wherein the rectangular shape of the central region has a first side bisector belonging to the first side as well as a second side bisector belonging to the second side, wherein the electrically conductive trace has a trace breadth of at least micrometer,
• wherein a ratio of first side length to second side length is greater than 3.25,
• wherein a measuring tube oscillatory deflection has an oscillation direction in parallel with the second side of the rectangular shape of the central region;
• wherein the magnet apparatus of a sensor or exciter on at least one measuring tube has at least one magnet having at least one magnet end surface facing toward the coil apparatus,
• wherein the magnet end surface is bounded by two, first magnet edges arranged opposite one another and two, second magnet edges arranged opposite one another,
• wherein, in the case of a measuring tube in rest position and considering the magnet end surface in a projection onto a first face of a circuit board layer, the second magnet edges extend in the direction of an oscillation direction of the measuring tube in parallel with the second side into the central region, wherein a first magnet edge facing the second side bisector is spaced a distance from the second side bisector, wherein the measuring tube is adapted to oscillate with an oscillation amplitude, wherein the distance is greater than half the oscillation amplitude,
• wherein the first magnet edge facing the second side bisector extends in parallel with the second side bisector.