Kyoto Electronics Manufacturing Company, Limited

Masanori Yasuda

Keiji Sakai

Kenji Kawaguchi

Nami Kurauchi

Miki Nakamura

A rotational speed detection device is provided that can detect the rotational speed of a rotating object with high precision by readily controlling a relatively inexpensive and compact optical device, and has a lower cost and a smaller size with maintained or improved detection precision of the rotational speed of the rotating object. The rotational speed detection device includes a light emitting unit (), a light receiving unit (), a received light data obtaining unit (), and a rotational speed calculation unit () that calculates the rotational speed of a rotating object (). The rotating object () has an irregular uneven portion (A) on a rotating surface thereof. The received light data obtaining unit () obtains time-series data of received light data of light reflected by the uneven portion (A). The rotational speed calculation unit () calculates the rotational speed of the rotating object () from the periodicity of the time-series data.

Rotational speed detection device, viscosity measurement device using the device, rotational speed detection method, and rotating object used in the method

In a method of measuring a viscosity of a sample based on a rotation frequency &#x3a9;of a conductive rotator rotating by applying a rotating magnetic field from outside to the rotator set in a container containing the sample and a rotation frequency &#x3a9;of the magnetic field, a constant khaving temperature dependency of an apparatus and a constant knot having the temperature dependency at each temperature are found by using a equation, &#x3b7;=k(&#x3a9;&#x2212;&#x3a9;)&#x2212;k, where a viscosity &#x3b7;at specific temperature is known, and then a value of viscosity measured at the specific temperature is corrected by means of the constants kand k, the rotation frequency &#x3a9;of the rotator, and the rotation frequency &#x3a9;of the magnetic field. The constant kmay employ the temperature dependency of electric conductivity of metal used to the rotator.

Method of measuring viscosity and viscosity measuring apparatus

A conductive rotator is immersed in a sample liquid in a sample container. A magnet is arranged at a specific distance from the rotation plane of the rotator in a direction of a rotating axis of the rotator so as to face the sample container. The magnet applies a magnetic field to the rotator from the outside of the sample container. A fluctuating magnetic field drive unit drives the magnet to apply the magnetic field that fluctuates in term of time to the rotator. Induced current is excited in the rotator by the fluctuating magnetic field. A rotating torque is provided to the rotator by the Lorenz interaction between the induced current and the fluctuating magnetic field, and as a result, the rotator rotates in the rotation plane. A viscosity detecting unit obtains the viscosity of the sample liquid based on a rotating state of the rotator and a time-fluctuating state of the fluctuating magnetic field.

Viscosity measuring apparatus

The invention relates to a method and apparatus for measuring a speed of an ultrasonic: wave propagated in a sample, even if there are bubbles in a sample. And it presupposes an ultrasonic speed measuring method for seeking a sonic speed in a sample in accordance with the propagation time of an ultrasonic wave propagated between an ultrasonic transmitter and an ultrasonic receiver by transmitting the ultrasonic wave from the ultrasonic transmitter. The apparatus of this invention is arranged that continuous oscillating waves are oscillated synchronizing the phase only with the receipt timing of at least one of receiving waves received by the ultrasonic receiver at every transmitting waves, and according to the continuous oscillating waves it is possible to measure the period of pulses oscillated by the local oscillator for determining the transmit timing.

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Kyoto, Japan

Masanori Yasuda