Viscosity estimation device and viscosity estimation method
AssigneeYokogawa Electric Corporation
InventorsHirofumi Okamoto, Eiji Taya, Katsuya Ohshima
Life of this patent
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Abstract
A viscosity estimation device includes: a current detector detecting a drive current supplied to an induction motor which stirs a substance due to rotation of a rotating shaft which is rotationally driven; a rotation detector detecting rotation of the rotating shaft; and a calculator obtaining a viscosity correlation value, which is a value having a correlation with a viscosity of the substance, using a detection result of the current detector and a detection result of the rotation detector.
Claims20
A viscosity estimation device configured to estimate a viscosity of a substance stirred by a rotation of a rotating shaft rotationally driven by an induction motor, the viscosity estimation device comprising:
- a current detector detecting a drive current supplied to the induction motor;
- a rotation detector detecting rotation of the rotating shaft;
- and
- a calculator obtaining a viscosity correlation value, which is a value having a correlation with a viscosity of the substance, using a detection result of the current detector and a detection result of the rotation detector,
- wherein the calculator comprises:
- a slip ratio calculator obtaining a slip ratio of the rotating shaft using the detection result of the current detector and the detection result of the rotation detector;
- an effective value calculator obtaining an effective value of the drive current from the detection result of the current detector;
- a frequency calculator obtaining a frequency of the drive current from the detection result of the current detector;
- and
- a viscosity correlation value calculator obtaining the viscosity correlation value using a calculation result of the slip ratio calculator, a calculation result of the effective value calculator, and a calculation result of the frequency calculator, and
- wherein the viscosity correlation value calculator is configured to obtain the viscosity correlation value by multiplying:
- a value obtained by dividing the frequency of the drive current by a rotation speed of the rotating shaft obtained by the detection result of the rotation detector;
- square of the effective value of the drive current;
- and
- the slip ratio of the rotating shaft.
A viscosity estimation method for estimating a viscosity of a substance stirred by a rotation of a rotating shaft rotationally driven by an induction motor, the viscosity estimation method comprising:
- detecting a drive current supplied to the induction motor;
- detecting rotation of the rotating shaft;
- and
- obtaining a viscosity correlation value, which is a value having a correlation with a viscosity of the substance, using a detection result of the drive current and a detection result of rotation of the rotating shaft,
- wherein during obtaining the viscosity correlation value:
- a slip ratio of the rotating shaft is obtained using the detection result of the drive current and the detection result of the rotation;
- an effective value of the drive current is obtained from the detection result of the drive current;
- a frequency of the drive current is obtained from the detection result of the drive current;
- and
- the viscosity correlation value is obtained using a calculation result of the slip ratio, a calculation result of the effective value, and a calculation result of the frequency,
- wherein the viscosity correlation value is obtained by multiplying:
- a value obtained by dividing the frequency of the drive current by a rotation speed of the rotating shaft obtained by the detection result of the rotation;
- square of the effective value of the drive current;
- and
- the slip ratio of the rotating shaft.
Dependencies are inferred from the claim text.