Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Panasonic Intellectual Property Management Co., Ltd.

Matsushita Electric Co., Ltd.

Fumikazu Shiba

Yuji Nakabayashi

Yuji Fujii

Yukio Nagaoka

Masahiko Hashimoto

Akihisa Adachi

Koichi Takemura

Yasuhiro Umekage

Kenzo Ohji

Shuji Abe

Osamu Eguchi

Daisuke Bessyo

Kouichi Takemura

Hiroyuki Ogino

Yasukiyo Ueda

Shunichi Nagamoto

Hiroaki Yonekubo

Yoshiaki Watanabe

Yasuo Kidouchi

Daisuke Bessho

Masayoshi Miki

A flow rate measurement device of the present invention includes a flow rate signal detection unit for detecting a flow rate signal of a fluid to be measured flowing through flow path, flow rate calculation unit for calculating a flow rate from the flow rate signal detected by the flow rate signal detection unit, and oscillation circuit for generating a reference clock. Furthermore, the flow rate measurement device includes temperature calculation unit for calculating a temperature from a frequency change resulting from a temperature change of oscillation circuit, and flow rate correction unit for correcting the flow rate calculated by the flow rate calculation unit by obtaining an offset flow rate at a desired temperature based on the temperature calculated by temperature calculation unit. Thus, accuracy of flow rate measurement can be improved.

Flow rate measurement device

In a flow meter device of the present invention, a unit measuring step is defined as a procedure for measuring ultrasonic sound wave propagation times by changing the direction in which an ultrasonic sound wave is transmitted and received between a first transducer and a second transducer, and a time measuring means measures a propagation time in a forward direction and a propagation time in a reverse direction in a unit measuring step. A time difference detecting means detects a difference between the propagation time in the forward direction and the propagation time in the reverse direction which are measured by the time measuring means. A determiner means determines whether or not there is a fluid flow based on the time difference. According to presence/absence of a fluid flow, the number of times the unit measuring step is performed is determined. Therefore, it can be determined whether or not there is a fluid flow quickly in real time. A responsiveness can be improved such that a measuring method can be switched to correspond to presence/absence of a fluid flow.

Flow meter device

In a flow meter device of the present invention, a time measuring section of the flow meter device includes a first counter which starts counting at a starting point of measurement of propagation time; and a second counter which starts counting at an end point of the measurement of the propagation time, and performs counting at a higher speed than the first counter. A propagation time TO is finally obtained by subtracting time &#x394;t which is measured by the second counter and passes from the end point until the first counter counts up, from time T which is measured by the first counter and passes from a starting point until the first counter counts up after the end point. A flow calculating section calculates a flow with high accuracy using the propagation time TO. Thus, lower electric power consumption can be achieved, and accuracy of measurement of flow can be improved.

To find the propagation time of an ultrasonic wave, a difference occurs between the waveforms received upstream and downstream in a portion where the reception amplitude is comparatively large and it is prevented from being detected as an error of the propagation time. A reception signal is amplified in a reception unitand reception point storage unitsstore the most recent reception point data in a plurality of storage sections in order until the signal level becomes a predetermined value (Vref). An average value of the two zero crossing points before and after the signal level becomes Vref can be adopted as a reception point, the propagation time with a small error of up and down offset, etc., is measured, and it is made possible to realize power saving operation by shortening the measurement time.

Flow measurement device

Switching a transmitting and receiving direction of two transducers () in the forward and the reverse direction, a time differential memory part () storing a propagation time differential every K times a unit measurement process being executed, the propagation time differential being a differential between a propagation time of the ultrasonic wave signal in a forward direction and in a reverse direction, a flow rate calculating part () calculating a flow rate of a passing fluid based on a lump sum of propagation times in both the forward and the reverse directions obtained at least every K times of a unit measurement process being executed, an estimating part () estimating a change in a momentary flow rate of the fluid based on the time differential obtained every K times of the unit measurement process being executed and storing thereof in a time differential memory part (), thus obtaining an accurate flow rate and detecting the change in the momentary flow rate.

The present invention provides an ultrasonic flowmeter comprising an oscillator and an oscillation start unit for accelerating oscillation of the oscillator. The oscillation start unit accelerates the oscillation of the oscillator so that pulses from the oscillator will become stable in a shorter time period. The accuracy of flow rate measurement is improved. Electric power can be saved where the flow rate is measured repeatedly at intervals.

Ultrasonic flowmeter including an oscillation start unit for acceleration stability of the oscillator

A measurement control section includes a time measuring section for controlling an operation of measuring a travel time of an ultrasonic wave. The measurement control section operations, based on a high rate clock signal supplied from a ceramic oscillation circuit during the time measuring operation. A clock control section stops the high rate clock signal supplied from the ceramic oscillation circuit every time when the time measuring section completes its time measuring operation, and uses a low rate clock signal supplied from a quartz oscillation circuit to count a standby time between the end of measuring the travel time and the start of carrying out the next measuring operation.

Fluid flow measuring instrument

An ultrasonic flowmeter includes a transmission/reception means provided in a flow path for performing transmission/reception using a state change of fluid; repetition means for repeating the transmission/reception; time measurement means for measuring a time of propagation repeated by the repetition means; flow rate detection means for detecting a flow rate based on a value of the time measurement means; and number-of-times change means for changing to a predetermined number of repetition times. With such a structure, an influence caused by a variation of a flow can be suppressed by changing the number of repetition times so as to be suitable for a variation. As a result, reliable flow rate measurement with a high accuracy can be achieved.

Ultrasonic flowmeter

In accordance with one embodiment, a flow meter of the present invention includes: transmission/reception means provided in a flow path for performing transmission/reception using a state change of fluid; repetition means for repeating the transmission/reception; time measurement means for measuring a time of propagation repeated by the repetition means; flow rate detection means for detecting a flow rate based on a value of the time measurement means; and number-of-times change means for changing to a predetermined number of repetition times. With such a structure, an influence caused by a variation of a flow can be suppressed by changing the number of repetition times so as to be suitable for a variation. As a result, reliable flow rate measurement with a high accuracy can be achieved.

Ultrasonic flowmeter including stable flow rate calculation means based on instantaneous flow rate

For the purpose of solving the above problems, the present invention includes: transmission/reception means provided in a flow path for performing transmission/reception using a state change of fluid; repetition means for repeating the transmission/reception; time measurement means for measuring a time of propagation repeated by the repetition means; flow rate detection means for detecting a flow rate based on a value of the time measurement means; and number-of-times change means for changing to a predetermined number of repetition times. With such a structure, an influence caused by a variation of a flow can be suppressed by changing the number of repetition times so as to be suitable for a variation. As a result, reliable flow rate measurement with a high accuracy can be achieved.

Ultrasonic flowmeter having sequentially changed driving method

A flow rate measurement apparatus includes: a plurality of flow paths provided between an inflow port and an outflow port ; opening/closing sections for opening/closing the plurality of flow paths ; measurement sections for measuring a flow rate of fluid flowing through at least one of the plurality of flow paths ; and a control section for controlling the opening/closing sections and the measurement sections ; The control section includes a gain adjustment section for correcting a gain of the measurement section in a flow path which is closed by the opening/closing section .

Flow rate measurement apparatus

A safety control apparatus positively discriminates between an object and a person through the detection of subtle physical movement corresponding to the heart activity and the breathing unique to the life activity of the human body from a output signal of a vibration sensor disposed on a seat so as to accurately decide whether or not a person is present. The maintenance of the safe operation of the moving vehicle can be realized. The starting of the moving vehicle is inhibited if the reserved seat is determined to be unoccupied in accordance with the decision result. In the case where the person is present, the moving of the vehicle is not started before the engagement of the seat belt has been detected.

Presence detecting and safety control apparatus

A hot-water and cold-water mixing device is provided wherein a hot-water side valve element and a cold-water side valve element are provided for regulating the respective flow rates of hot and cold water flows. The valve elements are constructed so as to possess a temperature regulating function exercised by varying the hot-water to cold-water mixing ratio depending on a biasing force, and also an automatic pressure regulating function to automatically accommodate any sudden pressure changes. The water mixing device of the foregoing construction is compact in size and is capable of adjusting the final water temperature reliably and speedily.

Growing community of inventors

Nara, Japan

Fumikazu Shiba