Rotating consistency measurement is based on measuring the reaction
torque (or shear-force) from a sensing element, which has a strong
physical relation to the fiber consistency. The accepted technology
comprises a double-shaft system with an outer hollow-shaft (1) and an
elastically connected inner (measuring) shaft (2) on to which the sensing
element (3) is attached. The outer shaft is driven by a motor, and for
achieving long-term stability and minimum sensitivity to disturbances, a
feed-back system counterbalances the reaction torque at the sensing
element keeping the measuring shaft in a controlled position within the
hollow-shaft.
The MEK-3000 TwinTorque takes advantage of an improved system
following the principle of force-balance (patent pending). A so-called
direct drive of the sensing element is achieved by applying a second
motor for driving the measuring shaft and sensing element attached to it.
The two motors are driven individually but at exactly the same rpm, with
a controlled angular displacement, measured by optical encoders (4).
Exploiting the total controllability and perfect relationship between the
torque and current of the motors (5,6), which are of brushless
permanent magnet type, results in extreme precision and accuracy in
the torque – and consistency – measurement