Fuji Electric Co., Ltd.

Fuji Electric Systems Co. Ltd.

The University of Tokyo

Masami Kishiro

Hironobu Yao

Noritomo Hirayama

Yoshinori Ohmuro

Toshihiro Yamamoto

Takahiro Kudo

Iwao Matsumoto

Kazuyuki Yamada

Hiroyuki Yoshimura

Satoru Sakaue

Tohru Asami

Takeshi Suzuki

Yoshihiro Kawahara

Yasufumi Morimoto

Keita Ohkawa

Shingo Noguchi

Keizo Murakami

Haruki Kawakami

Kouji Hagiwara

A fluid measuring apparatus, including a pair of ultrasonic wave probes in which one is disposed more upstream than the other, a processor, and a non-transitory storage medium containing program instructions therein. The execution of the program instructions by the processor causes the fluid measuring apparatus to provide functions of a period measuring unit that measures a first propagation period during which ultrasonic wave propagates from the one ultrasonic wave probe to the other, and a second propagation period during which ultrasonic wave propagates from the other ultrasonic wave probe to the one ultrasonic wave probe, and a flow velocity measuring unit that derives a flow velocity of the fluid by cancelling errors in a first flow velocity that is derived by measuring the second propagation period after measuring the first propagation period, and a second flow velocity that is derived by measuring the first propagation period after measuring the second propagation period.

Fluid measuring apparatus

A measurement apparatuscomprises a measurement unitto propagate, using sensorsandprovided in a pipe, a measurement wave in a mediumflowing through the pipe and receive the measurement wave, a trigger detecting sectionto detect whether or not a level of the received measurement wave exceeds a predetermined trigger level, and a specifying sectionto specify a reception timing of the measurement wave based on a waveform part in a period of the received measurement wave different from a period in which the level of the received measurement wave exceeds the trigger level.

Ultrasonic flow measuring apparatus detecting propagation time period from a zero cross point when a peak waveform exceeds a trigger level

A fluid measuring device in which an ultrasonic probe provided on an outer pipeline surface transmits and receives ultrasonic waves to and from fluid in a pipeline to measure characteristics of the fluid on the basis of propagation time of the ultrasonic waves, features a wedge included in the ultrasonic probe and having an ultrasonic vibrator provided on a wedge surface. The ultrasonic vibrator may be horizontal to a surface contacting the pipeline so that ultrasonic waves enter the fluid vertically. The ultrasonic vibrator may be provided on a wedge surface inclined with respect to an axial direction of the pipeline so that ultrasonic waves enter the fluid obliquely. The fluid measuring device embodiments are capable of measuring fluid characteristics, such as the type and velocity of various fluids, easily and accurately even when it is difficult to allow an ultrasonic signal to pass through the fluid in a pipeline.

Fluid measuring device including an ultrasonic probe having a wedge with an ultrasonic vibrator

A transmitting device includes: a compressing unit configured to generate and output a compressed digital signal that has been compressed, by converting an input digital signal by use of a Walsh function and extracting a specific frequency component.

Transmitting device, receiving device, and transmitting and receiving system

A capacitance detection circuit inhibits noise. The capacitance detection circuit detects a change in capacitance between a pair of electrodes of a physical quantity sensor, with these electrodes generating the change in capacitance in response to a change in physical quantity. The capacitance detection circuit has a carrier signal generating circuit that supplies a carrier signal to one of the electrodes, an operational amplifier that has an inverting input terminal to which the other one of the electrodes is input, a dummy capacity that is connected in parallel to the pair of electrodes, and a carrier signal conditioning circuit that inverts a phase of a carrier signal supplied from the carrier signal generating circuit to the dummy capacity and adjusts a gain to inhibit the dummy capacity.

Capacitance detection circuit

A capacitance detection circuit has at least a carrier signal generating circuit that supplies a carrier signal to one of a movable or a fixed electrode of a sensor, an operational amplifier with one of the movable or fixed electrode as an input and ground as another input, and a printed circuit board on which the physical quantity sensor, the carrier signal generating circuit, and the operational amplifier are mounted. An insulation-secured area on the printed circuit board is configured as a moisture absorption reduction area, including at least an electrode connection part of the physical quantity sensor, an input-side connection part of the operational amplifier, and a connection part connected to the input side of the operational amplifier out of connection parts of input-side circuit components connected between the electrode connection part and the input-side connection part.

An acceleration sensor can ensure rigidity of its movable electrode despite a large number of through-holes formed in the movable electrode. The acceleration sensor has an SOI substrate in which a silicon oxide layer is formed on a silicon support layer and an active silicon layer is formed on the silicon oxide layer, wherein the active silicon layer of the SOI substrate has a movable electrode supported by elastic beams and configured with a weight, and also has fixed electrodes disposed in a fixed manner around the movable electrode to face the movable electrode, and wherein through-holes penetrating in a Z-axis direction are formed over the entire surface on the inner side of an outer circumference to which the elastic beams of the movable electrode are connected.

Acceleration sensor

Provided is distribution device that distributes time information to at least one sensor device, the distribution device including a storage unit that stores a time adjustment amount to be used for adjusting a local time, a calculation unit that calculates a time difference between a reference time and the local time, an adjustment unit that calculates an adjusted local time by adjusting the local time by an amount equal to or less than the time adjustment amount, when the time difference is greater than the time adjustment amount, and a distribution unit that distributes time information of the adjusted local time to the sensor device.

Distribution device, distribution system, and distribution method

In a Doppler ultrasonic flowmeter, to obtain a precise flow rate a flow rate calculation equation that corrects a quantization error occurring to a spatial resolution is used. An ultrasonic transducer transmits/receives ultrasonic pulses, and subject the resulting received signals to A/D conversion after a predetermined process is applied thereto. A computation control section calculates the flow velocity distribution. Then, the flow rate is calculated based on the flow rate calculation equation, which corrects the quantization error occurring to the spatial resolution.

Doppler ultrasonic flowmeter, and processor and method thereof with quantization error correction

A flowmeter includes: a transit time method unit having a sensor and a reception signal amplification control unit and a flow rate calculation unit which are connected to the sensor via a sensor selector switch; a pulse Doppler method having a reception signal amplification control unit and an integration calculation unit which are connected to the sensor; a transmission/reception timing control unit common to them; a measurement method selection control unit for controlling switching between the transit time method unit and the pulse Doppler method unit, and parallel operation; and a measurement value output selector switch for selecting the output of the transit time method unit and the pulse Doppler method unit. That is, the single flowmeter can perform flow rate measurement by the transit time method having no restriction on the measurement range as well as by the pulse Doppler method having an upper limit of the measurement range but enabling a highly accurate measurement.

Ultrasonic flowmeter and ultrasonic flow rate measurement method

An apparatus and method for measuring a flow velocity profile of fluid traveling in a pipe or conduit uses an ultrasonic wave transmitted from an ultrasonic wave transducer mounted at an angle on the outside of a pipe using a wedge, and made incident onto the fluid in the pipe to measure the fluid flow velocity profile, using the principle that a frequency of an ultrasonic wave, reflected by a reflector existing in the fluid, is changed depending on a flow velocity due to Doppler effect. The transmission frequency and the angle of incidence onto the pipe can be selected to suppress frequency dependence of a measured value due to Lamb wave and allow the flow velocity or flow rate of fluid to be measured with a greater accuracy.

Apparatus and method for measuring a fluid flow rate profile using acoustic doppler effect

A vibration type measuring instrument measures at least one of density and mass flow rate of a fluid in a straight measurement pipe by vibrating the pipe. The vibration type measuring instrument comprises the pipe; a sensor for detecting the vibration of the pipe; and a signal processing circuit for obtaining the resonant angular frequency .omega. and axial force T based on the detection signal of the sensor, and obtaining the density .rho.w of the fluid flowing through the pipe using the obtained resonant angular frequency .omega. and axial force T. The density .rho.w is obtained by the following equation (E1). ##EQU1## (E: the Young's modulus of the pipe, I: a cross-sectional secondary moment of the pipe, Si: a cross-sectional area of the hollow portion of the pipe, .rho.t: a density of the pipe, St: the actual cross-sectional area of the pipe, L: the length in the axial direction of the pipe, x: a position in the axial direction of the pipe, y: a vibration amplitude of the pipe at position x, n: a number of masses added to the pipe, mk: a mass of a k-th added mass, and yk: a vibration amplitude of the k-th added mass).

Vibration type measuring instrument

A vibration type measuring instrument measures at least one of a mass flow rate and a density of a fluid flowing through a straight measurement pipe by vibrating the measurement pipe, obtains a frequency ratio of a resonant frequency of a first vibration mode to a resonant frequency of a second vibration mode of the measurement pipe, and corrects a measured value of at least one of the mass flow rate and the density according to the frequency ratio. The instrument includes a first vibration detector for detecting at least one of a vibration generated in the measurement pipe depending on the mass flow rate and the resonant frequency of the first vibration mode of the measurement pipe; and a second vibration detector for detecting the resonant frequency of the second vibration mode of the measurement pipe. The second vibration detector is provided around an antinode of the second vibration mode of the measurement pipe to improve the detection sensitivity in the second vibration mode.

A Coriolis mass flowmeter includes a housing which contains at least one measuring pipe, a supporting mechanism connected to both ends of the measuring pipe, a vibration generator which vibrates the measuring pipe, at least two sensors for detecting the vibration of the measuring pipe, an inlet conduit which introduces a fluid to be measured into the measuring pipe and an outlet conduit which discharges the fluid out of the measuring pipe. A Corioli vibration is applied to the measuring pipe which generates a Coriolis force in the fluid flowing in the measuring pipe. The Coriolis force is utilized for the measurement of the flow rate of the fluid. The Coriolis vibration has a frequency higher than the principal natural frequency of the supporting mechanism, i.e., in an inertial control region. The mass flowmeter is of a simple structure and lightweight, minimizes leakage of the energy of vibration to the outside, and has a high mechanical Q value.

Coriolis mass flowmeter

A mass flow meter provides improved accuracy in measuring the mass flow rate of a fluid flowing through a straight measuring tube. The as measured mass flow rate value is changed by parameters such as the Young's modules, second moment of area, length, axial force, etc. of the measuring tube. The parameters change with the strain caused in the axial direction of the measuring tube. A strain sensor is installed on a measuring tube, and the as measured mass flow rate is corrected based on the output of the strain sensor. Since the strain affects in a different way the substantial mass flow rate and the zero point offset, the correction is conducted separately on the substantial mass flow rate and on the zero point offset so that the accuracy of measurement may be improved. Since the parameters change also with the temperature of the measuring tube, a temperature sensor is also installed on the measuring tube so that the accuracy of measurement may be further improved.

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Hino, Japan

Masami Kishiro