Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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 ?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.

Abstract: 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 unit 35 and reception point storage units 38 store 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.

Abstract: 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 ?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.

Abstract: A flow control valve includes a light emitting section for emitting light; a light receiving section disposed so as to face the light emitting section, for detecting the amount of light received from the light emitting section; and a valve element for opening and closing a passage, wherein the valve element or a light blocking section secured to the valve element moves in a transverse direction between the light emitting section and the light receiving section as the passage is opened or closed, an amount of light received by the light receiving section from the light emitting section varies in accordance with the position of the valve element, and a position of the valve element is detected based on the amount of light received by the light receiving section.

Abstract: Switching a transmitting and receiving direction of two transducers (2,3) in the forward and the reverse direction, a time differential memory part (17b) 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 (15) 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 (18) 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 (17b), thus obtaining an accurate flow rate and detecting the change in the momentary flow rate.

Abstract: 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 (2) and a second transducer (3), and a time measuring means (12) 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 (16) 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 (12). A determiner means (17) 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.

Abstract: Switching a transmitting and receiving direction of two transducers (2,3) in the forward and the reverse direction, a time differential memory part (17b) 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 (15) 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 (18) 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 (17b), thus obtaining an accurate flow rate and detecting the change in the momentary flow rate.

Abstract: 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 unit 35 and reception point storage units 38 store 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.

Abstract: 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.

Abstract: It is desirable that an operation of an oscillator used for measuring propagation time of ultrasonic waves in an ultrasonic flowmeter be an intermittent operation in order to achieve electric power savings. However, pulse stability of the oscillator requires time, so that there is a problem that the intermittent operation cannot be performed. An ultrasonic flowmeter comprising an oscillator 60, and an oscillation start unit 61 for accelerating oscillation of the oscillator, constructed so that a pulse of the oscillator oscillated by the oscillation start unit 61 is used in measurement of propagation time of ultrasonic waves.

Abstract: 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.

Abstract: A measurement control section comprises 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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 pressed 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.