Panasonic Intellectual Property Management Co., Ltd.

Panasonic Corporation

Panasonic Holdings Corporation

Kouichi Takemura

Aoi Watanabe

Yasuo Koba

Yuji Fujii

Yuji Nakabayashi

Fumikazu Shiba

Masato Satou

Kenji Yasuda

Hiroshi Nakai

Hirokazu Gotou

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

Flow meter

A measurement control section of a flow meter device causes a measurement block dividing section to divide a sampling cycle Tc into three or more, for example, four measurement blocks Tb of an equal length and causes the flow measuring section to measure the flow of a fluid in each of the measurement blocks Tb. A flow calculating section of the flow measuring section calculates an average value of flow values obtained in all of the measurement blocks in each sampling cycle Tc, as a flow value in each sampling cycle Tc. This configuration allows a flow meter device which employs an inverse transit time difference method, such as an estimation gas meter, to more effectively lessen the influence of a pulsation and to perform flow measurement with higher accuracy.

Flow meter 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.

A setting method of a flow meter device comprises (A) measuring a compensation coefficient in a case where a fluid is flowed with a flow within a predetermined range, and deriving a first function representing as a linear function a relationship between a measurement compensation coefficient which is the measured compensation coefficient and a conversion value which is obtained by converting a set flow which is the flow of the flowed fluid, using a predetermined function; (B) setting a reference flow which is an arbitrary flow within the predetermined range and calculating a reference compensation coefficient which is a compensation coefficient corresponding to the reference flow based on the reference flow and the first function; and (C) storing the reference flow and the reference compensation coefficient corresponding to the reference flow.

Setting method of flow meter device and flow meter device

A flow meter device includes: a first vibrator, a second vibrator, a control unit, a timekeeper, and an arithmetic operation unit. The arithmetic operation unit is configured to: determine whether or not a time difference between a propagation time in the forward direction and a propagation time in the reverse direction is less than a predetermined value; calculate a propagation time correction amount based on the time difference if it is determined that the time difference is less than the predetermined value; and calculate a flow rate of the fluid by using the propagation time correction amount.

Ultrasonic flowmeter having an arithmetic operation unit for calculating propagation time correction value

A flow-rate measurement device includes a first transducer and a second transducer which are provided in a fluid flow path to transmit and receive an ultrasonic signal, a timer unit which measures a propagation time of the ultrasonic signal propagating between the first transducer and the second transducer, and a flow-rate calculation unit which executes a unit measurement step a predetermined number of times and calculates a flow rate of a fluid flowing in the fluid flow path on the basis of the propagation times measured the predetermined number of times, the unit measurement step being an operation in which a direction of transmission to reception between the first transducer and the second transducer is switched and the timer unit measures the propagation times of the ultrasonic signal in both directions. The flow-rate calculation unit measures a flow rate value of the fluid by a precise measurement step in which the unit measurement step is executed a plural number of times to calculate the flow-rate and an exploratory measurement step in which the unit measurement step is executed a smaller number of times than the number of executions in the precise measurement step to calculate the flow rate.

Flow-rate measurement device

A flow meter device of a fluid includes a time difference measuring means which measures time for a received wave to reach a zero cross point after the received wave exceeds a reference voltage, after transmission of a signal, and a reference voltage setting means which changes the reference voltage from a minimum value to a maximum value, recognizes peak voltages of waves of the received wave based on a plurality of inflection points at which a time difference measured by the time difference measuring means when the reference voltage is changed from the minimum voltage to the maximum voltage, is significantly changed, and automatically sets the reference voltage to a point between peak voltages of particular two waves based on a ratio between the peak voltages, and the reference voltage is changed from a voltage which is close to the peak voltages of the two waves and the peak voltages are newly recognized, when the reference voltage is newly set.

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.

When a flow rate is equal to or more than a reference flow rate, a reference voltage is changed to a level capable of measuring stably to thereby realize the improvement of measurement accuracy at the time of a large amount of flow rate. A flow rate determination means compares a flow rate calculated by a flow rate calculation means with the reference flow rate. When the calculated flow rate is larger than the reference flow rate, the reference voltage set by a reference voltage setting means is changed, whereby the zero cross point can be detected stably at the portion where the degree of the influence of the change in the amplitude of the received signal is small. Thus, it is possible to provide a flow rate measuring device capable of measuring a flow rate stably with high accuracy even when a fluid flow is disturbed due to a large amount of flow rate.

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Nara, Japan

Kouichi Takemura