Abstract: 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.

Abstract: 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.

Abstract: In a doppler type ultrasonic flow meter (1) for measuring the volumetric flow of a measurement object fluid (10) using doppler shift of ultrasound, a pair of ultrasonic transducers (3a, 3b) perform transmission of ultrasound and reception of an ultrasound echo resulting from the ultrasound being reflected. The ultrasonic transducers (3a, 3b) are disposed on an extension line of a measurement line ML for performing measurement of doppler shift, symmetrical about the center axis (5) of a pipe (2) with a measurement object fluid (10) flowing through its inside, and on the outside of the pipe (2). A flow profile for the side opposite, with respect to the center axis (5) of the pipe (2), the side on which the respective ultrasonic transducer (3a, 3b) is disposed is used for the calculation of the volumetric flow of the measurement object fluid (10).

Abstract: 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.

Abstract: In a doppler type ultrasonic flow meter 1 for measuring the volumetric flow of a measurement object fluid 10 using doppler shift of ultrasound, 1 pair of ultrasonic transducers 3a, 3b perform transmission of ultrasound and reception of an ultrasound echo resulting from the ultrasound being reflected. The 1 pair of ultrasonic transducers 3a, 3b are disposed on an extension line of a measurement line ML for performing measurement of doppler shift, symmetrical about the center axis 5 of a pipe 2 with a measurement object fluid 10 flowing through its inside, and on the outside of the pipe 2. A flow profile for the side opposite, with respect to the center axis 5 of the pipe 2, the side on which the respective ultrasonic transducer 3a, 3b is disposed is used for the calculation of the volumetric flow of the measurement object fluid 10.

Abstract: 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.

Abstract: 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.

Abstract: The reliability of a reception wave from a transducer is checked and when the reliability is determined to be insufficient, a method different from the current method is selected. The reliability is judged by calculating a value serving as an index of the reliability of the reception wave and checking whether the value is smaller than a predetermined set value. When the value is smaller than the set value, the reliability is judged to be insufficient.

Abstract: A wedge unit according to the present invention is used for an ultrasonic Doppler flow meter, being mounted on the outer wall of a pipe in which a fluid flows, supplying an ultrasonic wave to the fluid, receives the reflected wave and supplies the reflected wave to a flow rate calculation unit, comprises a wedge with one surface thereof being mounted on a part of the outer circumference of the pipe and on another surface thereof being equipped with an ultrasonic oscillator that generates the ultrasonic wave in response to an electric signal and receives the reflected wave; and an ultrasonic wave attenuation unit being mounted on the outer circumference of the pipe so as to include a position where an ultrasonic wave injected from the ultrasonic oscillator into the pipe by way of the wedge first reaches the outer wall of the pipe after being reflected by the inner wall thereof.

Abstract: 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.

Abstract: A wedge unit according to the present invention is used for an ultrasonic Doppler flow meter, being mounted on the outer wall of a pipe in which a fluid flows, supplying an ultrasonic wave to the fluid, receives the reflected wave and supplies the reflected wave to a flow rate calculation unit, comprises a wedge with one surface thereof being mounted on a part of the outer circumference of the pipe and on another surface thereof being equipped with an ultrasonic oscillator that generates the ultrasonic wave in response to an electric signal and receives the reflected wave; and an ultrasonic wave attenuation unit being mounted on the outer circumference of the pipe so as to include a position where an ultrasonic wave injected from the ultrasonic oscillator into the pipe by way of the wedge first reaches the outer wall of the pipe after being reflected by the inner wall thereof.

Abstract: A clamp-on type acoustic Doppler current profiler eliminates, among ultrasound echoes caused by two measurement lines of a longitudinal wave and a shear wave propagating in a piping, the ultrasound echo based on the longitudinal wave, thereby providing the measurement of a flow rate profile and/or a flow rate with a higher accuracy. The profiler includes a wedge mounted to the piping. The wedge includes an inclined surface at which an ultrasonic transducer can be mounted. The inclination is such that the ultrasound transducer receives only the ultrasound echo from the reflection of a shear wave component off the reflectors in the fluid.

Abstract: It is an object to provide an ultrasonic flow amount measuring device in which a direction and position of a transducer can be accurately fixed, thereby improving workability such as a reduction in working time. In order to attain the object, ultrasonic transducers 20 are fixed with a proper interval therebetween using a positioning portion 41 attached to a positioning frame 40. The position adjustment of the wave transducer 20 is automatically carried out through a positioning spring 25b and the positioning portion 41. A guide frame 30 can be mounted at a proper position on a conduit pipe 10 irrespective of the installation of the wave transducer. The guide frame 30 is mounted without paying attention to an interval between the ultrasonic transducers and coating an acoustic coupling medium on the conduit pipe, so that selection of a setup place, etc. can be freely performed.

Abstract: It is an object to provide an ultrasonic flow amount measuring device in which a direction and position of a transducer can be accurately fixed, thereby improving workability such as a reduction in working time. In order to attain the object, ultrasonic transducers 20 are fixed with a proper interval therebetween using a positioning portion 41 attached to a positioning frame 40. The position adjustment of the wave transducer 20 is automatically carried out through a positioning spring 25b and the positioning portion 41. A guide frame 30 can be mounted at a proper position on a conduit pipe 10 irrespective of the installation of the wave transducer. The guide frame 30 is mounted without paying attention to an interval between the ultrasonic transducers and coating an acoustic coupling medium on the conduit pipe, so that selection of a setup place, etc. can be freely performed.

Abstract: 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.

Abstract: A mass flowmeter for measuring the flow rate of a fluid by generating a Coriolis force in a measuring pipe includes a housing and a mechanism for supporting the pipe in the housing. The support mechanism includes a generally cylindrical hollow beam and first and second end support members. The measuring pipe is supported inside the hollow beam by the end support members. A vibrator for vibrating the measuring pipe and two sensors for detecting these vibrations are provided in the housing. The effective vibrating length of the measuring pipe is set shorter than the effective vibrating length of the support mechanism so as to set the vibration frequency of the measuring pipe higher than the natural frequency of the support mechanism, without reducing the rigidity of the support mechanism or using any additional mass.

Abstract: 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.

Abstract: 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.

Abstract: The precision of phase difference obtained by a phase difference calculating unit is improved by correction through outputs of a frequency ratio calculating unit and a temperature calculating unit considering that the phase or time difference of each output signal of a vibration sensor indicating the mass flow or density of a fluid is a function of the temperature and axial force on a measurement pipe, or that the axial force is a function of the ratio between two resonant frequencies.

Abstract: A pressure measuring apparatus comprising a seal diaphragm that separates a fluid to be measured from a pressure transmitting medium that transmits a pressure variation of the fluid to be measured to a pressure detecting section. In such an apparatus, a non-electrically conductive film is coated on a surface of the seal diaphragm which is on the side of the fluid to be measured. As a result of the above construction, the pressure can be measured accurately over a long period of time while preventing hydrogen from passing through the seal diaphragm surely and protecting the seal diaphragm.