Patent ID: 7347107
Filing Date: 2008-03-25
Classification: G01L,G01N

Abstract:
1. Device for a torque or shear force transmitter for determination of fibre concentration or viscosity in pulp suspensions and which is adapted to measure an angle deviation between two concentric shafts ( 9 , 11 ), of which the outer is driven with a constant rotational speed while the inner, which is influenced by a present resistance torque in the suspension via a measuring body ( 5 ), is elastically connected to the outer, whereby the arisen angle deviation form a function of the torque applied on the measuring body ( 5 ), characterized in a feedback system for bringing the inner shaft or measuring shaft ( 11 ) to take a zero position independent of the magnitude of the torque, which system comprises an electromagnetic feedback coil ( 18 ), which encircles two pole shoes ( 19 ) journalled in bearing points ( 20 ) at the end of the outer shaft in the form of a hollow shaft ( 9 ), at the same time as each pole shoe ( 19 ) is connected to the measuring shaft ( 11 ), whereby a current, generated by means of a transducer ( 12 ) and dependent on the present angle deviation, is sent to the winding ( 23 ) of the coil ( 18 ), where a magnetic field of force ( 25 ) is generated, whose strength is determined by the current flowing through the coil ( 18 ) and the distance ( 24 ), which arise between the pole shoes ( 19 ) and the magnetic parts of the feedback coil, which latter obtain different polarity and provide a resetting of the pole shoes ( 19 ) to a preset set point together with the measuring shaft ( 11 ) and which current magnitude is a measure of the present shear force torque, which is convertible to suitable output signal.