Viscosity measuring device and viscosity measuring method
AssigneeNational Institute of Advanced Industrial Science and Technology
InventorsMasaharu Kuroda, Hiroshi Yabuno
Life of this patent
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Abstract
The oscillating velocity of an oscillating body in a fluid to be measured is positively fed back, so as to activate an actuator. The oscillating state of the oscillating body is monitored while making a velocity feedback gain increase. The velocity feedback gain when the oscillating body has oscillated is obtained as an oscillation limit gain at the oscillation limit, and this oscillation limit gain is used as a viscosity equivalent value representing viscosity of the measured fluid.
Claims9
A viscosity measuring method, using a viscosity measuring device comprising:
- an oscillating body put in a fluid to be measured;
- an actuator for making the oscillating body oscillate self-excitedly;
- an oscillating velocity detector for detecting an oscillating velocity of the oscillating body;
- and
- a controller that generates positive feedback of the oscillating velocity detected by the oscillating velocity detector so as to activate the actuator according to a feedback control signal Fs represented by an equation:
- Fs=Cc·(dx/dt),
- where Fs denotes a feedback control signal, Cc denotes a linear velocity feedback gain, and dx/dt denotes the oscillating velocity of the oscillating body;
- wherein the viscosity measuring method comprises the steps of:
- changing the linear velocity feedback gain for feedback control;
- using the linear velocity feedback gain at a time when the oscillating body changes between a non-oscillation mode and an oscillating mode as an oscillation limit gain;
- and
- detecting the oscillation limit gain as a viscosity equivalent value representing viscosity of the fluid.
A viscosity measuring device, comprising:
- an oscillating body put in a fluid to be measured;
- an actuator for making the oscillating body oscillate self-excitedly;
- an oscillating velocity detector for detection of an oscillating velocity of the oscillating body;
- a controller that generates positive feedback of the oscillating velocity detected by the oscillating velocity detector so as to feedback control the actuator according to a feedback control signal Fs represented by an equation:
- Fs=Cc·(dx/dt),
- where Fs denotes a feedback control signal, Cc denotes a linear velocity feeedback gain, and dx/dt denotes the oscillating velocity of the oscillating body;
- a gain adjustor for changing the linear velocity feedback gain of the controller;
- and
- a viscosity equivalent value detector for setting the linear velocity feedback gain at a time when the oscillating body changes between a non-oscillation mode and an oscillating mode as an oscillation limit gain for giving an oscillation limit, and for detecting the oscillation limit gain as a viscosity equivalent value representing viscosity of the fluid.
Dependencies are inferred from the claim text.