JP2010164585A - Ultrasonic flow rate measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the measurement accuracy of flow rate or flow quantity, by measuring a travelling period with more high accuracy, through accurate detection of a reception waveform of normal travelling wave, while reducing unwanted traveling waves which leak in the case of a measurement flow path, without enhancing the pressure loss. <P>SOLUTION: This device includes the measurement flow path; an ultrasonic wave transducer mounted at the measurement flow path; a second unwanted traveling wave attenuation means which attenuates unwanted traveling wave of the ultrasonic waves traveling the flow path wall which is forming the measurement flow path; a measurement control part which measures the traveling period of the ultrasonic waves among the ultrasonic wave transducer; an operation part which calculates the flow quantity based on the signal from the measurement control part, and a vibration transmission suppression means which is included in the second unwanted traveling wave attenuation means is mounted inside the flow path wall between the ultrasonic wave transducer of the flow measurement path, and thereby the transmission and reception of the ultrasonic waves can be attained at a high sensitivity and with superior S/N characteristics, and the traveling wave passing through the measurement path can be received with accuracy; and measurement accuracy of the flow rate or flow quantity can be enhanced. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an ultrasonic flow rate measuring apparatus that measures the flow rate and flow velocity of a gas or liquid by ultrasonic waves.

  Conventionally, this type of ultrasonic flow rate measuring apparatus is known from Japanese Patent Application Laid-Open No. 11-351926, and is opposed to a measurement channel 1 for flowing a fluid from one side to the other as shown in FIGS. In addition, an upstream ultrasonic transmitter / receiver 2a and a downstream transmitter / receiver 2b are provided so as to be inclined at a predetermined angle with respect to the flow direction of the measurement channel 1, and the ultrasonic transmitter / receiver 2a, 2b While housed in the recesses 3 a and 3 b provided in the channel 1, a flow fluctuation suppressing means 5 is provided on the inlet side 4 of the measurement channel 1. The flow entering the measurement flow path 1 is regulated by the flow fluctuation inhibiting means 5 to stabilize the flow by equalizing the flow velocity distribution in the measurement unit and suppressing the generation of vortices. In this state in which the flow is stabilized by the flow fluctuation suppressing means 5, the ultrasonic wave is propagated in the width W direction of the measurement cross section of the measurement channel 1, and the direct wave directly propagated in the measurement channel 1 is opposed. In addition to receiving with the ultrasonic transmitter / receiver, the fluctuation of ultrasonic reception level due to reflection and refraction of ultrasonic waves at the boundary of flow disturbance is reduced to prevent deterioration of measurement accuracy, and high-precision flow measurement is performed. It was.

Japanese Patent Laid-Open No. 11-351926

  However, in the conventional configuration, the ultrasonic wave transmitted from one ultrasonic transmitter / receiver is not only a direct wave directly directed to the other ultrasonic transmitter / receiver but also a plane in the width W direction of the measurement channel 1 formed in a rectangular cross section. A reflected wave is generated on the flow path wall 1a or the flow path wall 1b of the plane H in the height direction of the measurement flow path 1, and this reflected wave that is delayed with respect to the direct wave is transmitted to the other ultrasonic transceiver. There is a problem that the measurement accuracy of the propagation time of the ultrasonic wave is deteriorated because it is detected as an interference wave in which the direct wave and the reflected wave interfere with each other.

  The present invention solves the above-mentioned problem, reduces the unnecessary propagation wave in the measurement channel without increasing the pressure loss, accurately detects the reception waveform of the regular propagation wave, and makes the propagation time more accurate. The purpose is to improve the measurement accuracy of flow velocity or flow rate.

  In order to solve the above problems, the present invention provides a measurement channel through which a fluid to be measured flows, an ultrasonic transmitter / receiver provided in the measurement channel, and an ultrasonic wave propagating through a channel wall forming the measurement channel. Second unnecessary propagation wave attenuation means for attenuating unnecessary propagation waves, a measurement control unit for measuring the propagation time of ultrasonic waves between the ultrasonic transceivers, and a flow rate based on a signal from the measurement control unit An ultrasonic flow rate measuring device including a calculation unit, wherein the second unnecessary propagation wave attenuating means includes vibration transmission suppressing means provided inside the flow path wall between the ultrasonic transceivers of the measurement flow path. Is.

According to the above invention, when the ultrasonic wave transmitted from the transmitting-side ultrasonic transceiver propagates in the measuring channel to the receiving-side ultrasonic transmitter / receiver, unnecessary vibration leaking to the housing of the measuring channel is It is attenuated and received by the receiving-side ultrasonic receiver, and the receiving-side ultrasonic receiver eliminates the influence of the propagation wave from the measurement flow path housing and has a high S / N characteristic. Sensitive ultrasonic waves can be transmitted and received, and the propagation wave that has passed through the measurement channel can be received accurately, the measurement accuracy of flow velocity or flow rate can be improved, and the measurement range of flow velocity or flow rate that can be measured can be expanded. .

  As is apparent from the above description, the ultrasonic flow rate measuring device of the present invention provides the following effects. Since the first unnecessary propagation wave attenuation means for attenuating the unnecessary propagation wave of the ultrasonic wave propagating in the measurement channel is provided, the unnecessary propagation wave deviating from the normal propagation path is the first unnecessary propagation wave attenuation means. The ultrasonic transmitter / receiver on the receiving side can receive the signal by increasing the ratio of the normal propagation wave that has passed through the normal propagation path in the measurement channel, and the received waveform with less noise component is detected and the S / N is detected. It has the effect of making it possible to send and receive highly sensitive ultrasonic waves with excellent characteristics, and it can improve the measurement accuracy of flow velocity or flow rate by measuring the propagation time with higher accuracy. There is an effect that it is possible to expand the measurement range by enlarging or reducing the measurement lower limit value.

  In addition, since the second unnecessary propagation wave attenuating means for attenuating the unnecessary propagation wave of the ultrasonic wave propagating through the flow channel wall forming the measurement flow channel is provided, the ultrasonic wave transmitted from the ultrasonic transceiver on the transmission side is provided. Is propagated through the measurement channel to the receiving side ultrasonic transceiver, the unnecessary vibration leaking to the measurement channel housing is attenuated and received by the receiving side ultrasonic transceiver. The ultrasonic transmitter / receiver on the side has the effect of enabling transmission / reception of highly sensitive ultrasonic waves with excellent S / N characteristics by eliminating the influence of the propagation wave from the measurement channel housing. There is an effect that the propagating wave that has passed can be accurately received, the measurement accuracy of flow velocity or flow rate can be improved, and the measurement range can be expanded.

  In addition, since there is a third unnecessary propagation wave attenuating means for attenuating disturbance vibration that has entered from the external piping, external vibration waves that pass through the external piping connected to the connection port (for example, close to the piping system) It is possible to reduce the arrival to the ultrasonic transmitter / receiver by attenuating disturbances such as ultrasonic vibration waves of other installed ultrasonic flow measuring devices, etc., and to receive highly sensitive ultrasonic waves with excellent S / N characteristics. It is possible to accurately receive the propagation wave that has passed through the measurement flow path, improve the measurement accuracy of flow velocity or flow rate and expand the measurement range, and can be freely positioned regardless of other ultrasonic flow measurement devices Therefore, there is an effect that the degree of freedom of installation is high and convenience can be improved.

  In addition, a first unnecessary propagation wave attenuation means for attenuating the unnecessary propagation wave of the ultrasonic wave propagating in the measurement channel, and a first attenuation unit for attenuating the unnecessary propagation wave of the ultrasonic wave propagating through the channel wall forming the measurement channel. Since there is a second unnecessary propagation wave attenuation means and a third unnecessary propagation wave attenuation means that attenuates disturbance vibrations that have entered from outside piping, even if disturbances are added, the third unnecessary propagation wave attenuation means Propagation of vibration waves due to disturbance to the measurement channel is reduced, and unnecessary vibration leaking to the channel wall forming the measurement channel is transmitted to the ultrasonic transmitter / receiver on the receiving side by the second unnecessary propagation wave attenuation means. It is attenuated before it reaches the receiver, and the ultrasonic transmitter / receiver on the receiving side uses the first unwanted propagation wave attenuation means to increase the ratio of the normal propagation wave that has passed through the normal propagation path in the measurement channel. A received waveform with few components is detected and S It has the effect of being able to transmit and receive highly sensitive ultrasonic waves with excellent N characteristics, and can further improve the measurement accuracy of flow velocity or flow rate by measuring the propagation time with higher accuracy, and can measure the flow velocity or flow rate that can be measured. There is an effect that the measurement range can be further expanded by expanding the upper limit value or reducing the measurement lower limit value. Furthermore, there is an effect that a flow rate measuring device that is resistant to disturbance can be realized, the degree of freedom of the installation position of other flow rate measuring devices can be increased, and the installability can be improved.

A measurement channel through which the fluid to be measured flows, an ultrasonic transmitter / receiver provided in the measurement channel, and a first unnecessary propagation wave attenuating means for attenuating an unnecessary propagation wave of the ultrasonic wave propagating in the measurement channel; A second unnecessary propagation wave attenuating means for attenuating the unnecessary propagation wave of the ultrasonic wave propagating through the flow path wall forming the measurement flow path, and a measurement control unit for measuring the propagation time of the ultrasonic wave between the ultrasonic transceivers, And an arithmetic unit that calculates a flow rate based on a signal from the measurement control unit. Unnecessary vibration leaking to the flow path wall forming the measurement flow path is attenuated by the second unnecessary propagation wave attenuating means before reaching the ultrasonic transmitter / receiver on the reception side, and further, the first unnecessary propagation wave attenuation is performed. The ultrasonic transmitter / receiver on the receiving side can receive the signal by increasing the ratio of the normal propagation wave that has passed through the normal propagation path, can detect the reception waveform with less noise component, and has high S / N characteristics and high sensitivity. Ultrasonic wave can be transmitted and received, and the propagation time can be measured with higher accuracy, so that the measurement accuracy of flow velocity or flow rate can be further improved, and the measurement upper limit value of flow velocity or flow rate can be increased or the measurement lower limit value is reduced. The range can be further expanded.

  In addition, a measurement channel through which the fluid to be measured flows, an ultrasonic transmitter / receiver provided in the measurement channel, a connection port connected to an external pipe connected to the measurement channel, and an ultrasonic wave propagating in the measurement channel Propagation time of ultrasonic waves between the first unnecessary propagation wave attenuating means for attenuating unnecessary propagation waves of sound waves, the third unnecessary propagation wave attenuating means for attenuating disturbance vibrations entering from external piping, and the ultrasonic transceiver And a calculation unit that calculates a flow rate based on a signal from the measurement control unit. Even when disturbances are applied, the third unnecessary propagation wave attenuation means reduces the propagation of vibration waves due to the disturbance to the measurement channel, and the first unnecessary propagation wave attenuation means reduces the ultrasonic transmission / reception on the receiving side. Since the receiver can receive signals with a higher ratio of the normal propagation wave that has passed through the normal propagation path, it can detect the received waveform with less noise component and transmit / receive highly sensitive ultrasonic waves with excellent S / N characteristics. The measurement accuracy of flow velocity or flow rate can be further improved by measuring the propagation time with higher accuracy, and the measurement range can be further expanded by increasing the measurement upper limit value of the flow velocity or flow rate or reducing the measurement lower limit value. it can. Furthermore, it is possible to realize a flow rate measuring device that is resistant to disturbance, and the degree of freedom of the installation position of other flow rate measuring devices is increased, thereby improving the installation property.

  In addition, a measurement channel through which the fluid to be measured flows, an ultrasonic transmitter / receiver provided in the measurement channel, a connection port connected to an external pipe connected to the measurement channel, and a channel forming the measurement channel Between the ultrasonic transmitter / receiver, the second unnecessary propagation wave attenuating means for attenuating the unnecessary propagation wave of the ultrasonic wave propagating through the wall, the third unnecessary propagation wave attenuating means for attenuating the disturbance vibration invading from the external pipe, and the ultrasonic transceiver A measurement control unit that measures the propagation time of ultrasonic waves and a calculation unit that calculates a flow rate based on a signal from the measurement control unit are provided. Even when disturbances are applied, the third unnecessary propagation wave attenuating means reduces the propagation of vibration waves due to the disturbance to the measurement channel, and leaks to the casing of the channel wall that forms the measurement channel Unnecessary vibration is attenuated by the second unnecessary propagation wave attenuation means before reaching the reception-side ultrasonic transmitter / receiver, and the reception-side ultrasonic transmitter / receiver eliminates the influence of the propagation wave from the measurement channel housing. This makes it possible to detect a received waveform with less noise components and to transmit / receive highly sensitive ultrasonic waves with excellent S / N characteristics, and to measure the propagation time with higher accuracy, thereby further increasing the measurement accuracy of flow velocity or flow rate. The measurement range can be further expanded by increasing the measurement upper limit value or decreasing the measurement lower limit value of the measurable flow velocity or flow rate. Furthermore, it is possible to realize a flow rate measuring device that is resistant to disturbance, and the degree of freedom of the installation position of other flow rate measuring devices is increased, thereby improving the installation property.

  The first unnecessary propagation wave attenuating means is provided with first sound absorbing means provided on the inner surface of the flow path wall forming the measurement flow path. And by arranging the optimum sound absorbing means at any position on the inner wall of the measurement flow path, it is possible to efficiently attenuate unnecessary propagation waves by suppressing the generation of reflected waves without increasing the pressure loss of the fluid to be measured. .

  The first unnecessary propagation wave attenuating means is provided with a second sound absorbing means provided in an opening hole that allows the ultrasonic transceiver to directly face the measurement channel. And by reducing the generation of unnecessary reflected waves in the aperture hole and reducing the transmission of unnecessary waves to the measurement flow path, it is possible to transmit and receive highly sensitive ultrasonic waves with excellent S / N characteristics, thereby improving measurement accuracy. Can be increased.

The first unnecessary propagation wave attenuating means is a first sound absorbing means provided on the inner surface of the flow path wall that forms the measurement flow path and a second provided in the opening hole that directly faces the ultrasonic transceiver to the measurement flow path. Sound absorbing means. In addition, transmission of unnecessary waves to the measurement channel and unnecessary reflected waves in the measurement channel are reduced, enabling highly sensitive transmission / reception of ultrasonic waves with even better S / N characteristics, and improved measurement accuracy. The ultrasonic transmitter / receiver can realize low voltage driving by a battery or the like.

  The first unnecessary propagation wave attenuating means is provided with irregular reflection means provided on the inner surface of the channel wall forming the measurement channel. Even if an unnecessary wave that deviates from the normal ultrasonic wave propagation path is generated in the measurement channel, the unnecessary wave is irregularly reflected in all directions by the irregular reflection means provided on the inner surface of the measurement channel. Therefore, even when a part of the unwanted wave reaches the receiving side, the unwanted wave is weakened by diffuse reflection, so the noise on the receiving side can be reduced, and highly sensitive ultrasonic waves with excellent S / N characteristics can be transmitted and received. Measurement accuracy can be increased.

  The second unnecessary propagation wave attenuating means is provided with vibration transmission suppressing means provided between the ultrasonic transceivers of the measurement channel. And even if an unnecessary propagation wave of the ultrasonic wave transmitted to the casing forming the measurement flow channel leaks, the unnecessary propagation wave is transmitted to the ultrasonic transmission / reception unit before the vibration transmission suppressing means. Is attenuated, and the ultrasonic transmitter / receiver on the receiving side eliminates unnecessary waves propagating through the casing of the measurement flow path, and increases the ratio of the ultrasonic component that has passed through the normal propagation path in the measurement flow path. High-sensitivity ultrasonic waves with excellent characteristics can be transmitted and received, and the propagating wave that has passed through the measurement channel can be accurately received, and the measurement accuracy of flow velocity or flow rate can be improved and the measurement range can be expanded.

  Further, the second unnecessary propagation wave attenuating means is provided with sound insulation means provided on the outer surface of the flow path wall forming the measurement flow path. And even if vibrations such as ultrasonic waves are applied from the outside, the disturbance vibrations are attenuated by the sound insulation means that covers the measurement flow path, and the ultrasonic transmitter / receiver can transmit and receive ultrasonic waves without the influence of disturbance vibrations. It is possible to measure the flow velocity or flow rate that is strong against the noise and improve the reliability.

  The second unnecessary propagation wave attenuating means includes a vibration transmission suppressing means provided between the ultrasonic transceivers of the measurement flow path and a sound insulation means provided on the outer surface of the flow path wall forming the measurement flow path. is there. And, unnecessary waves propagating through the housing are eliminated, and the measurement accuracy is improved by transmitting and receiving highly sensitive ultrasonic waves with excellent S / N characteristics, the measurement range is expanded, and the influence of ultrasonic waves that eliminate the influence of disturbance vibrations is eliminated. It is possible to improve reliability against disturbance caused by transmission and reception, and to improve practicality.

  Further, the vibration transmission suppressing means connects the upstream flow path wall where the upstream ultrasonic transceiver is arranged and the downstream flow path wall where the downstream ultrasonic transceiver is arranged via a damping body. Is. And since the unnecessary wave leaking from the ultrasonic transmitter / receiver on the transmission side to the casing of the measurement flow path is blocked by the damping body and does not reach the ultrasonic transmitter / receiver on the reception side, the S / N characteristic is further improved. High-sensitivity ultrasonic waves can be transmitted and received, and measurement accuracy and measurement range can be further improved.

  Further, the second unnecessary propagation wave attenuating means is one in which the channel wall of the measurement channel is formed of a damping material. In addition, the configuration of the measurement channel can be simplified while maintaining transmission / reception of highly sensitive ultrasonic waves with excellent S / N characteristics, and the practicality can be improved by reducing the size, weight and cost of the measurement channel. it can.

  Further, the sound insulation means has a heat insulating performance. In addition to realizing measurement of flow velocity or flow rate that is resistant to disturbance vibrations, measurement of flow velocity or flow rate is reduced by reducing the influence on the measurement flow path such as sonic fluctuations and dew condensation caused by external heat such as solar radiation and ambient temperature changes. Accuracy reliability can be improved.

The third unnecessary propagation wave attenuating means includes an external vibration suppressing means interposed between the connection port and the flow path wall forming the measurement flow path. And the disturbance which passed through the external piping connected to the connection port is interrupted by the external vibration suppression means to prevent the intrusion into the measurement flow path, and the disturbance noise which has entered from the connection port is further reduced and the S / N. Highly sensitive ultrasonic waves can be received according to the characteristics, and the propagating wave that has passed through the measurement channel can be accurately received, and the measurement accuracy and measurement range of flow velocity or flow rate can be further improved.

  The third unnecessary propagation wave attenuating means includes an inlet block or an outlet block formed of a damping material on the upstream side or the downstream side of the measurement flow path. In addition, the configuration of the measuring device can be simplified while reducing the disturbance noise that has entered from the connection port and maintaining the transmission / reception of highly sensitive ultrasonic waves with excellent S / N characteristics, and the measuring device can be reduced in size, weight, and cost. Practicality can be improved by making it easier.

  The third unnecessary propagation wave attenuating means is provided with heat insulation performance. And the influence on the measurement flow path by the heat from the outside, such as the solar radiation which entered into the connection port or the measurement apparatus, and the external temperature change, can be reduced, and the reliability of the measurement accuracy of the flow velocity or the flow rate can be improved.

Sectional drawing of composition of an ultrasonic flow measuring device of Example 1 of the present invention. AA cross-sectional arrow view of the measurement channel in FIG. Cross-sectional view of the configuration of an ultrasonic flow measuring device showing another embodiment of the present invention FIG. 3 is a cross-sectional view of the measurement channel showing the first sound absorbing means in FIG. Cross-sectional view of the configuration of an ultrasonic flow measuring device showing another embodiment of the present invention Cross-sectional view of the configuration of an ultrasonic flow measuring device showing another embodiment of the present invention Sectional drawing of composition of an ultrasonic flow measurement device of Example 2 of the present invention. BB cross section of the measurement channel in FIG. BB sectional drawing of a measurement channel which shows other examples of the present invention. BB sectional drawing of a measurement channel which shows other examples of the present invention. BB sectional drawing of a measurement channel which shows other examples of the present invention. Cross-sectional view of the configuration of the ultrasonic flow rate measuring apparatus according to the third embodiment of the present invention Cross-sectional view of the configuration of an ultrasonic flow measuring device showing another embodiment of the present invention Sectional drawing of composition of the ultrasonic flow measuring device of Example 4 of the present invention. Sectional drawing of a structure of the ultrasonic flow measuring device of Example 5 of the present invention Sectional drawing of composition of an ultrasonic flow measurement device of Example 6 of the present invention. Sectional drawing of composition of an ultrasonic flow measurement device of Example 7 of the present invention. Configuration of conventional ultrasonic flow measurement device Cross-sectional view of the measurement flow path in FIG.

  The present invention provides a measurement channel through which a fluid to be measured flows, an ultrasonic transmitter / receiver provided in the measurement channel, and a first unnecessary propagation wave attenuation that attenuates an unnecessary propagation wave of ultrasonic waves propagating in the measurement channel. Means, a measurement control unit that measures the propagation time of the ultrasonic wave between the ultrasonic transceivers, and a calculation unit that calculates the flow rate based on a signal from the measurement control unit. The unnecessary propagation wave deviating from the normal propagation path is attenuated by the first unnecessary propagation wave attenuating means, and the normal propagation wave that has passed through the normal propagation path in the measurement channel is received by the receiving-side ultrasonic transceiver. The received waveform with less noise component can be detected and the highly sensitive ultrasonic wave with excellent S / N characteristics can be transmitted and received, and the propagation time can be measured with higher accuracy, so that the flow velocity or flow rate The measurement accuracy can be improved, and the measurement range can be expanded by expanding the measurement upper limit value or decreasing the measurement lower limit value of the measurable flow velocity or flow rate.

In addition, the measurement channel through which the fluid to be measured flows, the ultrasonic transmitter / receiver provided in the measurement channel, and the second unnecessary attenuation of the unnecessary propagation wave of the ultrasonic wave propagating through the channel wall forming the measurement channel The apparatus includes a propagation wave attenuating unit, a measurement control unit that measures the propagation time of the ultrasonic wave between the ultrasonic transceivers, and a calculation unit that calculates the flow rate based on a signal from the measurement control unit. When the ultrasonic wave transmitted from the transmitting-side ultrasonic transceiver propagates in the measuring channel to the receiving-side ultrasonic transmitter / receiver, unnecessary vibration leaking to the housing of the measuring channel is attenuated and received. Is received by the ultrasonic transmitter / receiver on the receiving side, and the ultrasonic transmitter / receiver on the receiving side eliminates the influence of the propagation wave from the measurement flow path casing, and thereby has high S / N characteristics. Transmission / reception becomes possible, and the propagating wave that has passed through the measurement channel can be accurately received, and the measurement accuracy of flow velocity or flow rate can be improved and the measurement range can be expanded.

  In addition, the measurement flow path through which the fluid to be measured flows, the ultrasonic transmitter / receiver provided in the measurement flow path, the connection port connected to the external pipe connected to the measurement flow path, and the disturbance vibration that has entered from the external pipe A third unnecessary propagation wave attenuating means for attenuating, a measurement control unit for measuring the propagation time of the ultrasonic wave between the ultrasonic transceivers, and a calculation unit for calculating the flow rate based on a signal from the measurement control unit It is a thing. Then, external disturbances such as external vibration waves (for example, ultrasonic vibration waves of other ultrasonic flow measuring devices installed nearby in the piping system) via external pipes connected to the connection ports are attenuated and supersonic waves are attenuated. Reducing the arrival to the sound wave transmitter / receiver, enabling the reception of highly sensitive ultrasonic waves with excellent S / N characteristics, enabling accurate reception of propagation waves that have passed through the measurement flow path, Improvement and expansion of the measurement range are possible, and it can be installed at any position regardless of other ultrasonic flow rate measuring devices, so the degree of freedom of installation is high and convenience can be improved.

  In addition, a measurement channel through which the fluid to be measured flows, an ultrasonic transmitter / receiver provided in the measurement channel, a connection port connected to an external pipe connected to the measurement channel, and an ultrasonic wave propagating in the measurement channel A first unnecessary propagation wave attenuating means for attenuating an unnecessary propagation wave of a sound wave; a second unnecessary propagation wave attenuating means for attenuating an unnecessary propagation wave of an ultrasonic wave propagating through a channel wall forming a measurement channel; and an external A third unnecessary propagation wave attenuation means for attenuating disturbance vibration that has entered from the pipe, a measurement control unit that measures the propagation time of the ultrasonic wave between the ultrasonic transceivers, and a flow rate based on the signal from the measurement control unit And a calculation unit for calculating. Even when disturbances are applied, the third unnecessary propagation wave attenuating means reduces the propagation of vibration waves due to disturbances to the measurement flow path, and unnecessary vibration leaks to the flow path walls forming the measurement flow path. Is attenuated by the second unnecessary propagation wave attenuating means before reaching the receiving-side ultrasonic transmitter / receiver, and further, the first unnecessary propagation wave attenuating means is used for the receiving-side ultrasonic transmitter / receiver in the measurement channel. The ratio of the regular propagation wave that has passed through the propagation path can be increased and received, detection of the received waveform with less noise component is made, and high-sensitivity ultrasonic waves with excellent S / N characteristics can be transmitted and received. The measurement accuracy of the flow velocity or flow rate can be further improved by being able to measure with higher accuracy, and the measurement range can be further expanded by increasing the measurement upper limit value or decreasing the measurement lower limit value of the measurable flow velocity or flow rate.Furthermore, it is possible to realize a flow rate measuring device that is resistant to disturbance, and the degree of freedom of the installation position of other flow rate measuring devices is increased, thereby improving the installation property.

  A measurement channel through which the fluid to be measured flows, an ultrasonic transmitter / receiver provided in the measurement channel, and a first unnecessary propagation wave attenuating means for attenuating an unnecessary propagation wave of the ultrasonic wave propagating in the measurement channel; A second unnecessary propagation wave attenuating means for attenuating the unnecessary propagation wave of the ultrasonic wave propagating through the flow path wall forming the measurement flow path, and a measurement control unit for measuring the propagation time of the ultrasonic wave between the ultrasonic transceivers, And an arithmetic unit that calculates a flow rate based on a signal from the measurement control unit. Unnecessary vibration leaking to the flow path wall forming the measurement flow path is attenuated by the second unnecessary propagation wave attenuating means before reaching the ultrasonic transmitter / receiver on the reception side, and further, the first unnecessary propagation wave attenuation is performed. The ultrasonic transmitter / receiver on the receiving side can receive the signal by increasing the ratio of the normal propagation wave that has passed through the normal propagation path, can detect the reception waveform with less noise component, and has high S / N characteristics and high sensitivity. Ultrasonic wave can be transmitted and received, and the propagation time can be measured with higher accuracy, so that the measurement accuracy of flow velocity or flow rate can be further improved, and the measurement upper limit value of flow velocity or flow rate can be increased or the measurement lower limit value is reduced. The range can be further expanded.

In addition, a measurement channel through which the fluid to be measured flows, an ultrasonic transmitter / receiver provided in the measurement channel, a connection port connected to an external pipe connected to the measurement channel, and an ultrasonic wave propagating in the measurement channel Propagation time of ultrasonic waves between the first unnecessary propagation wave attenuating means for attenuating unnecessary propagation waves of sound waves, the third unnecessary propagation wave attenuating means for attenuating disturbance vibrations entering from external piping, and the ultrasonic transceiver And a calculation unit that calculates a flow rate based on a signal from the measurement control unit. Even when disturbances are applied, the third unnecessary propagation wave attenuation means reduces the propagation of vibration waves due to the disturbance to the measurement channel, and the first unnecessary propagation wave attenuation means reduces the ultrasonic transmission / reception on the receiving side. Since the receiver can receive signals with a higher ratio of the normal propagation wave that has passed through the normal propagation path, it can detect the received waveform with less noise component and transmit / receive highly sensitive ultrasonic waves with excellent S / N characteristics. The measurement accuracy of flow velocity or flow rate can be further improved by measuring the propagation time with higher accuracy, and the measurement range can be further expanded by increasing the measurement upper limit value of the flow velocity or flow rate or reducing the measurement lower limit value. it can. Furthermore, it is possible to realize a flow rate measuring device that is resistant to disturbance, and the degree of freedom of the installation position of other flow rate measuring devices is increased, thereby improving the installation property.

  In addition, a measurement channel through which the fluid to be measured flows, an ultrasonic transmitter / receiver provided in the measurement channel, a connection port connected to an external pipe connected to the measurement channel, and a channel forming the measurement channel Between the ultrasonic transmitter / receiver, the second unnecessary propagation wave attenuating means for attenuating the unnecessary propagation wave of the ultrasonic wave propagating through the wall, the third unnecessary propagation wave attenuating means for attenuating the disturbance vibration invading from the external pipe, and the ultrasonic transceiver A measurement control unit that measures the propagation time of ultrasonic waves and a calculation unit that calculates a flow rate based on a signal from the measurement control unit are provided. Even when disturbances are applied, the third unnecessary propagation wave attenuating means reduces the propagation of vibration waves due to the disturbance to the measurement channel, and leaks to the casing of the channel wall that forms the measurement channel Unnecessary vibration is attenuated by the second unnecessary propagation wave attenuation means before reaching the reception-side ultrasonic transmitter / receiver, and the reception-side ultrasonic transmitter / receiver eliminates the influence of the propagation wave from the measurement channel housing. This makes it possible to detect a received waveform with less noise components and to transmit / receive highly sensitive ultrasonic waves with excellent S / N characteristics, and to measure the propagation time with higher accuracy, thereby further increasing the measurement accuracy of flow velocity or flow rate. The measurement range can be further expanded by increasing the measurement upper limit value or decreasing the measurement lower limit value of the measurable flow velocity or flow rate. Furthermore, it is possible to realize a flow rate measuring device that is resistant to disturbance, and the degree of freedom of the installation position of other flow rate measuring devices is increased, thereby improving the installation property.

  The first unnecessary propagation wave attenuating means is provided with first sound absorbing means provided on the inner surface of the flow path wall forming the measurement flow path. And by arranging the optimum sound absorbing means at any position on the inner wall of the measurement flow path, it is possible to efficiently attenuate unnecessary propagation waves by suppressing the generation of reflected waves without increasing the pressure loss of the fluid to be measured. .

  The first unnecessary propagation wave attenuating means is provided with a second sound absorbing means provided in an opening hole that allows the ultrasonic transceiver to directly face the measurement channel. And by reducing the generation of unnecessary reflected waves in the aperture hole and reducing the transmission of unnecessary waves to the measurement flow path, it is possible to transmit and receive highly sensitive ultrasonic waves with excellent S / N characteristics, thereby improving measurement accuracy. Can be increased.

  The first unnecessary propagation wave attenuating means is a first sound absorbing means provided on the inner surface of the flow path wall that forms the measurement flow path and a second provided in the opening hole that directly faces the ultrasonic transceiver to the measurement flow path. Sound absorbing means. In addition, transmission of unnecessary waves to the measurement channel and unnecessary reflected waves in the measurement channel are reduced, enabling highly sensitive transmission / reception of ultrasonic waves with even better S / N characteristics, and improved measurement accuracy. The ultrasonic transmitter / receiver can realize low voltage driving by a battery or the like.

  The first unnecessary propagation wave attenuating means is provided with irregular reflection means provided on the inner surface of the channel wall forming the measurement channel. Even if an unnecessary wave that deviates from the normal ultrasonic wave propagation path is generated in the measurement channel, the unnecessary wave is irregularly reflected in all directions by the irregular reflection means provided on the inner surface of the measurement channel. Therefore, even when a part of the unwanted wave reaches the receiving side, the unwanted wave is weakened by diffuse reflection, so the noise on the receiving side can be reduced, and highly sensitive ultrasonic waves with excellent S / N characteristics can be transmitted and received. Measurement accuracy can be increased.

  The second unnecessary propagation wave attenuating means is provided with vibration transmission suppressing means provided between the ultrasonic transceivers of the measurement channel. And even if an unnecessary propagation wave of the ultrasonic wave transmitted to the casing forming the measurement flow channel leaks, the unnecessary propagation wave is transmitted to the ultrasonic transmission / reception unit before the vibration transmission suppressing means. Is attenuated, and the ultrasonic transmitter / receiver on the receiving side eliminates unnecessary waves propagating through the casing of the measurement flow path, and increases the ratio of the ultrasonic component that has passed through the normal propagation path in the measurement flow path. High-sensitivity ultrasonic waves with excellent characteristics can be transmitted and received, and the propagating wave that has passed through the measurement channel can be accurately received, and the measurement accuracy of flow velocity or flow rate can be improved and the measurement range can be expanded.

  Further, the second unnecessary propagation wave attenuating means is provided with sound insulation means provided on the outer surface of the flow path wall forming the measurement flow path. And even if vibrations such as ultrasonic waves are applied from the outside, the disturbance vibrations are attenuated by the sound insulation means that covers the measurement flow path, and the ultrasonic transmitter / receiver can transmit and receive ultrasonic waves without the influence of disturbance vibrations. It is possible to measure the flow velocity or flow rate that is strong against the noise and improve the reliability.

  The second unnecessary propagation wave attenuating means includes a vibration transmission suppressing means provided between the ultrasonic transceivers of the measurement flow path and a sound insulation means provided on the outer surface of the flow path wall forming the measurement flow path. is there. And, unnecessary waves propagating through the housing are eliminated, and the measurement accuracy is improved by transmitting and receiving highly sensitive ultrasonic waves with excellent S / N characteristics, the measurement range is expanded, and the influence of ultrasonic waves that eliminate the influence of disturbance vibrations is eliminated. It is possible to improve reliability against disturbance caused by transmission and reception, and to improve practicality.

  Further, the vibration transmission suppressing means connects the upstream flow path wall where the upstream ultrasonic transceiver is arranged and the downstream flow path wall where the downstream ultrasonic transceiver is arranged via a damping body. Is. And since the unnecessary wave leaking from the ultrasonic transmitter / receiver on the transmission side to the casing of the measurement flow path is blocked by the damping body and does not reach the ultrasonic transmitter / receiver on the reception side, the S / N characteristic is further improved. High-sensitivity ultrasonic waves can be transmitted and received, and measurement accuracy and measurement range can be further improved.

Further, the second unnecessary propagation wave attenuating means is one in which the channel wall of the measurement channel is formed of a damping material. In addition, the configuration of the measurement channel can be simplified while maintaining transmission / reception of highly sensitive ultrasonic waves with excellent S / N characteristics, and the practicality can be improved by reducing the size, weight and cost of the measurement channel. it can.

  Further, the sound insulation means has a heat insulating performance. In addition to realizing measurement of flow velocity or flow rate that is resistant to disturbance vibrations, measurement of flow velocity or flow rate is reduced by reducing the influence on the measurement flow path such as sonic fluctuations and dew condensation caused by external heat such as solar radiation and ambient temperature changes. Accuracy reliability can be improved.

  The third unnecessary propagation wave attenuating means includes external vibration suppressing means interposed between the connection port and the flow path wall forming the measurement flow path. And the disturbance which passed through the external piping connected to the connection port is interrupted by the external vibration suppression means to prevent the intrusion into the measurement flow path, and the disturbance noise which has entered from the connection port is further reduced and the S / N. Highly sensitive ultrasonic waves can be received according to the characteristics, and the propagating wave that has passed through the measurement channel can be accurately received, and the measurement accuracy and measurement range of flow velocity or flow rate can be further improved.

  The third unnecessary propagation wave attenuating means includes an inlet block or an outlet block formed of a damping material on the upstream side or the downstream side of the measurement flow path. In addition, the configuration of the measuring device can be simplified while reducing the disturbance noise that has entered from the connection port and maintaining the transmission / reception of highly sensitive ultrasonic waves with excellent S / N characteristics, and the measuring device can be reduced in size, weight, and cost. Practicality can be improved by making it easier.

The third unnecessary propagation wave attenuating means is provided with heat insulation performance. And the influence on the measurement flow path by the heat from the outside, such as the solar radiation which entered into the connection port or the measurement apparatus, and the external temperature change, can be reduced, and the reliability of the measurement accuracy of the flow velocity or the flow rate can be improved.

  Embodiments of the present invention will be described below with reference to the drawings.

Example 1
FIG. 1 is a cross-sectional view of the configuration of an ultrasonic flow rate measuring apparatus showing Embodiment 1 of the present invention. In FIG. 1, reference numeral 6 denotes a measurement flow path surrounded by a flow path wall 7, and 8 and 9 denote superstructures provided upstream and downstream of the measurement flow path so as to face each other with the measurement flow path 6 interposed therebetween. It is a sound wave transceiver. The ultrasonic transmitters / receivers 8 and 9 are attached to the flow path wall 7 via a support 10 that performs vibration isolation and airtight sealing, and the upstream ultrasonic transmitter / receiver 8 and the downstream ultrasonic transmitter / receiver 9 are separated by a distance L. And is inclined at an angle θ with respect to the longitudinal direction of the measurement channel 6. Reference numerals 11 and 12 are upstream and downstream opening holes that allow the ultrasonic transceivers 8 and 9 to face the fluid to be measured flowing through the measurement flow path 6, and are recessed with respect to the flow path wall 7. Reference numeral 13 denotes an ultrasonic wave propagation path (a region indicated by a two-dot chain line) in which an ultrasonic wave transmitted between the opposing ultrasonic transmitters / receivers 8 and 9 propagates directly to the ultrasonic transmitter / receiver on the other side without being reflected on the wall surface. is there. Reference numeral 14 denotes first unnecessary propagation wave attenuation means provided in the measurement flow path 6, and this first unnecessary propagation wave attenuation means 14 is located in the vicinity of the upstream side of the ultrasonic propagation path 13 in the width W direction of the measurement flow path 6. Are arranged so as to be divided and a first sound absorbing means 15 formed of a sound absorbing material extending in the flow direction is provided. The first sound absorbing means 15 can use a resin as a breathable foam, a metal porous sound absorbing material, a nonwoven fabric such as felt or glass wool, and the height H of the measurement channel 6 as shown in FIG. It is formed and arranged over the entire direction. In particular, as the material of the first sound absorbing means, a metal porous foam material such as aluminum is a rigid body, so that it can be easily installed in the measurement flow path 6 and the fibers are dispersed in a nonwoven fabric such as felt or glass wool. Therefore, the fluid to be measured is not polluted and the reliability is high. Furthermore, since the deterioration over time is small, it can be used stably over a long period of time and has excellent durability.

  Reference numeral 16 denotes an inflow suppressing body provided on the inlet side of the measurement flow path 6, which is installed so as to be fitted in a depression provided in the flow path wall 7 so that there is no step with the flow path wall 7. This inflow suppressing body 16 has a direction restricting portion 16a for adjusting the flow direction of the fluid to be measured and a fluctuation suppressing portion 16b for equalizing the flow velocity distribution or reducing flow pulsation. The direction restricting portion 16 a is provided with a partition wall that divides the cross section of the measurement flow path 6, and the fluctuation suppressing portion 16 b is short in the flow direction and has many fine shapes with respect to the cross section of the measurement flow path 6. It has a communication path. Reference numeral 17 denotes a bent portion communicating with an on-off valve (not shown) provided on the upstream side of the measurement channel 6, and 18 denotes a bent portion on the downstream side of the measurement channel 6. The bent portions 17 and 18 make the channel compact. It is configured. Reference numeral 19 denotes a measurement control unit that is connected to the ultrasonic transmitters / receivers 8 and 9 and transmits / receives ultrasonic waves. Reference numeral 20 denotes an arithmetic unit that calculates a flow rate based on a signal from the measurement control unit 19 and calculates a flow rate.

  Next, the flow measurement operation using ultrasonic waves will be described. In the ultrasonic wave propagation path 13 of the measurement flow path 6, ultrasonic waves are transmitted and received between the ultrasonic transmitters / receivers 8 and 9 by the action of the measurement control unit 19 with respect to the flow so as to cross the measurement flow path 6. That is, the propagation time T1 until the ultrasonic wave emitted from the upstream ultrasonic transceiver 8 is received by the downstream ultrasonic transceiver 9 is measured. On the other hand, the propagation time T2 until the ultrasonic wave emitted from the ultrasonic transmitter / receiver 9 on the downstream side is received by the ultrasonic transmitter / receiver 8 on the upstream side is measured.

  Based on the propagation times T1 and T2 thus measured, the flow rate is calculated by the calculation unit 20 using the following calculation formula.

  Now, the angle between the flow velocity V of the fluid to be measured in the longitudinal direction of the measurement flow path 5 and the ultrasonic propagation path is θ, the distance between the ultrasonic transceivers 7 and 8 is L, and the sound velocity of the fluid to be measured is C. Then, the flow velocity V is calculated by the following formula.

T1 = L / (C + V cos θ)
T2 = L / (C−Vcos θ)
The speed of sound C is eliminated from the equation for subtracting the reciprocal of T2 from the reciprocal of T1, and V = (L / 2 cos θ) ((1 / T1) − (1 / T2))
Since θ and L are known, the flow velocity V can be calculated from the values of T1 and T2. Now, assuming that the flow rate of air is measured, assuming an angle θ = 45 degrees, a distance L = 70 mm, a sound velocity C = 340 m / s, and a flow velocity V = 8 m / s, T1 = 2.0 × 10 ⁻⁴ seconds, T2 = 2.1 × 10 ⁻⁴ seconds, and instantaneous measurement is possible.

Here, from the cross-sectional area s orthogonal to the flow direction of the measurement channel 5, the flow rate Q is Q = kVs.
Here, k is a conversion coefficient considering the flow velocity distribution in the cross-sectional area s.

  In this way, the flow rate can be obtained by the calculation unit 20.

  Next, the flow state and ultrasonic wave propagation in the measurement flow path of this ultrasonic flow rate measuring device will be described. The measured fluid remains unbalanced or pulsates due to the fluid being measured being enlarged or reduced in the cross-sectional area of the flow path at an on-off valve (not shown) provided on the upstream side of the measurement flow path 6 or flowing through the bent portion 17. Enter road 6. In the measurement flow path 6, the flow in the cross section of the measurement flow path 6 is rectified in a direction that hardly flows into the opening holes 11 and 12 by the direction restricting portion 16 a of the second inflow suppressing body 16 provided on the upstream side of the ultrasonic wave propagation path 13. The flow is reduced and the flow disturbance is reduced. Further, the fluctuation suppressing portion 16b reduces the disturbance due to the flow fluctuation such as pulsation so that the inflow into the opening holes 11 and 12 is further suppressed. To flow into. The fluctuation suppressing portion 16b can reduce the pressure loss due to the fluctuation suppressing portion 16b by thinning a mesh-like mesh, a foam, a fine porous plate, a nonwoven fabric, etc. having a high opening ratio in the flow direction, and does not increase the pressure loss. In addition, fluctuations in the flow in the measurement channel can be reduced.

  With respect to this rectified flow, in the ultrasonic wave propagation path 13, most of the ultrasonic waves transmitted from one ultrasonic transmitter / receiver 8 or 9 are not reflected on the flow path wall 7 and are opposed as direct waves. Received by the transceiver 9 or 8. However, a part of the ultrasonic wave transmitted from the ultrasonic transmitter / receiver 8 or 9 exits from the ultrasonic wave propagation path 13 spreading radially through the opening hole 11 or 12. In particular, the ultrasonic wave transmitted from the ultrasonic transmitter / receiver 8 on the upstream side has a shape in which the wall surface of the opening hole 11 is first opened to the measurement flow path 6 on the upstream side, and therefore, on the upstream side of the ultrasonic wave propagation path 13. The ultrasonic waves transmitted from the ultrasonic transmitter / receiver 9 on the downstream side easily spread to the downstream side of the ultrasonic wave propagation path 13. However, the multiple reflection path deviated from the ultrasonic wave propagation path 13 (an example is shown by a broken line in the figure) is the first unnecessary propagation wave attenuation constituted by the first sound absorbing means 15 formed of the sound absorbing material extending in the flow direction. Since the ultrasonic wave which is blocked by the means 14 and deviates from the ultrasonic propagation path 13 and arrives at the first unnecessary propagation wave attenuation means 14 is absorbed and attenuated, the reflected wave which reaches the opposing ultrasonic transmitter / receiver 9 or 8 is absorbed. Is reduced. For this reason, the reception-side ultrasonic transceiver can measure a correct received waveform with an increased direct wave ratio, and the direct wave directly propagated without reflecting the ultrasonic propagation path 13 and the flow path wall 7 of the measurement flow path 6. Since the interference wave having a phase shift due to the interference with the reflected wave reflected on the surface is not measured, the measurement accuracy at the times T1 and T2 can be improved, and so-called sing-around is repeated in order to increase and decrease the measurement accuracy. By reducing the number of times, the measurement time can be shortened and the power consumption can be reduced. When a battery is used as the power source, the battery can be used for a long time without replacing the battery, and the convenience can be improved by extending the service life.

In this way, unnecessary propagation waves that deviate from the normal propagation path are attenuated by the first unnecessary propagation wave attenuation means, and in the ultrasonic transmitter / receiver on the receiving side, the regular propagation wave that has passed through the regular propagation path in the measurement channel is obtained. Highly sensitive ultrasonic waves with excellent S / N characteristics can be transmitted and received by detecting the received waveform with a low noise component, which can be received by increasing the ratio of the propagating wave, and the propagation time can be measured with higher accuracy. Alternatively, the flow rate measurement accuracy can be improved, and the measurement range can be expanded by increasing the measurable flow velocity or flow rate measurement upper limit value or reducing the measurement lower limit value. Further, by dividing the width W direction of the measurement flow path 6 by the first sound absorbing means 15 extending in the flow direction as in this embodiment, the flow rectification is strengthened and the flow into the opening holes 11 and 12 is further increased. It is possible to significantly reduce vortices and flow turbulence, and transmission / reception of ultrasonic waves with excellent S / N characteristics can improve the measurement upper limit and improve measurement accuracy.

  The ultrasonic waves transmitted from the upstream ultrasonic transmitter / receiver 8 and deviated upstream of the ultrasonic wave propagation path 13 and the ultrasonic waves transmitted from the downstream ultrasonic wave transmitter / receiver 9 and deviated from the ultrasonic wave propagation path 13 are the first. Although the sound reaches the one sound absorbing means 15 and is absorbed, the ultrasonic wave transmitted from the upstream ultrasonic transmitter / receiver 8 and deviating to the downstream side of the ultrasonic wave propagation path 13 is reflected even if it is reflected by the flow path wall. Since it does not reach the acoustic wave transmitter / receiver 9, the first sound absorbing means 15 does not have to be provided on the downstream side of the ultrasonic wave propagation path 13, but the first sound absorbing means 15 is also provided on the downstream side to reduce the reflected wave. Since the sound absorbing action can be enhanced and the flow of the fluid to be measured can be made more stable, it is needless to say that the first sound absorbing means is preferably provided also on the downstream side of the ultrasonic wave propagation path 13. Can be measured accurately.

  FIG. 3 is a block diagram showing another embodiment of the first unnecessary propagation wave attenuating means. The same members and the same functions as those in the embodiment of FIG. The explanation is centered. In FIG. 3, reference numeral 21 denotes first sound absorbing means provided on the inner surface of the flow path wall 7 forming the measurement flow path 6, and the first sound absorbing means 21 is a surface without protruding from the inner surface of the flow path wall 7. It is installed so that the flow of the measurement flow path 6 is not disturbed. The first sound absorbing means 21 is the first unnecessary propagation wave attenuating means 14.

  Next, propagation of ultrasonic waves will be described. As described above, most of the ultrasonic waves transmitted from the ultrasonic transmitter / receiver 8 or 9 pass through the ultrasonic wave propagation path 13 and reach the opposing ultrasonic transmitter / receiver 9 or 8. However, when the ultrasonic wave deviating from the ultrasonic wave propagation path 13 (an example of the path is indicated by a broken line in the figure) reaches the first sound absorbing means 15 installed on the inner wall surface that determines the width W of the measurement flow path 6. Since the sound is absorbed and attenuated, the multiple reflected waves reaching the opposing ultrasonic transmitter / receiver 9 or 8 are attenuated and reduced. For this reason, as described above, the ultrasonic transmitter / receiver on the receiving side can measure the correct received waveform with a higher direct wave ratio, improve the measurement accuracy, reduce the measurement time and power consumption, and power the battery. In this case, the battery can be used without replacing the battery for a long time, and the convenience can be improved by extending the service life. Furthermore, since the first sound absorbing means 15 can be arranged so as not to disturb the flow of the measurement flow path 6, it can reduce the pressure loss without increasing the pressure loss of the fluid to be measured, so that a large flow rate flows through the compact flow path. be able to. Here, the case where the first sound absorbing means 15 is installed on the inner wall surface that determines the width W of the measurement flow path 6 has been described. However, the height H of the measurement flow path 6 is determined as shown in FIG. It goes without saying that the attenuation effect of the reflected wave can be further enhanced by arranging the first sound absorbing means 15 on the wall surface.

  In this way, by arranging the optimal sound absorbing means at any position on the inner wall of the measurement flow path, it is possible to efficiently attenuate unnecessary propagation waves by suppressing the generation of reflected waves without increasing the pressure loss of the fluid to be measured. Can do.

FIG. 5 is a block diagram showing another embodiment of the first unnecessary propagation wave attenuating means. The same members and the same functions as those in the embodiment of FIGS. The explanation will focus on the differences. In FIG. 5, reference numeral 22 denotes a second sound absorbing means that is provided on the inner surfaces of the opening holes 11 and 12 and is formed of a sound absorbing material. The second sound absorbing means 22 is installed so as to cover a surface along the propagation direction of the ultrasonic waves. is doing. Here, first, a case where ultrasonic waves are transmitted from the ultrasonic transmitter / receiver 8 on the upstream side will be described. A part of the ultrasonic wave transmitted from the ultrasonic transmitter / receiver 8 collides with the inner surface of the opening hole 11 to generate a reflected wave, but the reflected wave in the opening hole 11 is the second sound absorbing means 22 installed on the inner surface. The ultrasonic wave emitted from the aperture hole 11 in the direction deviating from the ultrasonic wave propagation path 13 is reduced and the ultrasonic wave having a higher direct wave ratio can be transmitted to the ultrasonic wave transmitter / receiver 9 on the downstream side. The received waveform can be measured with less noise components. Similarly, when transmitting from the downstream ultrasonic transmitter / receiver 9, the upstream ultrasonic transmitter / receiver 8 can measure the received waveform with less noise components. In this way, it is possible to transmit and receive highly sensitive ultrasonic waves with excellent S / N characteristics by reducing the generation of unnecessary reflected waves in the aperture holes and reducing the transmission of unnecessary waves to the measurement channel. Accuracy can be increased.

  When the first unnecessary propagation wave attenuation means 14 includes the second sound absorbing means 22 provided in the opening holes 11 and 12 and the first sound absorbing means 21 provided in the measurement flow path 6, In addition to the effect of the action of reducing the reflected waves within 11 and 12, even if a component deviating from the ultrasonic wave propagation path 13 occurs due to the propagation of the transmitted waves that have exited the aperture holes 11 and 12 to propagate, Thus, since the sound is absorbed and attenuated by the first sound absorbing means 21, it is possible to measure a received waveform with a higher direct wave ratio to the opposing ultrasonic transmitter / receiver. For this reason, the transmission of unnecessary waves to the measurement channel and the unnecessary reflected waves in the measurement channel are reduced, and it is possible to transmit and receive highly sensitive ultrasonic waves with superior S / N characteristics. The ultrasonic transmitter / receiver can be driven at a low voltage by a battery or the like. In addition, when it is set as the 1st sound absorption means 15 arrange | positioned so that the width W direction of the measurement flow path 6 shown in FIG. In addition to the above effect, the measurement upper limit value and the measurement accuracy can be improved by reducing the flow into the opening hole by the flow rectifying action.

  FIG. 6 is a block diagram showing another embodiment of the first unnecessary propagation wave attenuating means. The same members and the same functions as those of the embodiment of FIGS. The explanation will focus on the differences. In FIG. 6, reference numeral 23 denotes irregular reflection means provided on the inner wall surface of the flow channel wall 7 that determines the width W of the measurement flow channel 6, and is arranged so as not to protrude from the inner wall surface of the measurement flow channel 6 to disturb the flow. I am trying not to. The irregular reflection means 23 has a surface irregularity height Hs larger than 1/4 of the wavelength λ of ultrasonic waves (Hs> λ / 4). For example, the frequency of ultrasonic waves is 200 kHz and the fluid to be measured is at room temperature. In the case of air (sonic velocity of 340 m / s), the wavelength of the ultrasonic wave is λ = 1.7 mm, and the irregular reflection means 23 has a surface unevenness height Hs larger than 0.425 mm.

  Here, when an unnecessary propagation wave deviating from the ultrasonic wave propagation path 13 collides with the irregular reflection means 23, the unnecessary propagation wave is irregularly reflected in all directions, not in a fixed direction, and therefore, unnecessary propagation reaching the ultrasonic transmitter / receiver on the receiving side. Waves can be weakened and the received waveform can be measured with a higher direct wave ratio. Further, by forming the irregular reflection means 23 with a sound absorbing material, unnecessary propagation waves that reach the ultrasonic transmitter / receiver on the receiving side can be further reduced by both the effect of irregular reflection and the attenuation effect due to sound absorption.

  Further, by combining the irregular reflection means 23 and the first sound absorbing means 15 or 21 or the second sound absorbing means 22 as the first unnecessary propagation wave attenuating means 14, the noise of the received waveform is further reduced and the S / N is reduced. The characteristics can be improved to improve measurement accuracy and reduce power consumption.

  In this way, even if an unnecessary wave that deviates from the normal ultrasonic wave propagation path is generated in the measurement channel, the unnecessary wave is irregularly reflected in all directions instead of a fixed direction by the irregular reflection means provided on the inner surface of the measurement channel. Therefore, even when a part of the unwanted wave reaches the receiving side, the unwanted wave is weakened by irregular reflection, so that the noise on the receiving side can be reduced, and highly sensitive ultrasonic waves with excellent S / N characteristics can be transmitted and received. Measurement accuracy can be increased.

As described above, according to the present embodiment, since the first unnecessary propagation wave attenuation means for attenuating the unnecessary propagation wave is provided, the unnecessary propagation wave deviating from the normal propagation path is attenuated by the first unnecessary propagation wave. The ultrasonic transmitter / receiver on the receiving side can receive the signal by increasing the ratio of the normal propagation wave that has passed through the normal propagation path in the measurement channel, and the received waveform with less noise component is detected. High-sensitivity ultrasonic waves with excellent N characteristics can be sent and received, and the propagation time can be measured with higher accuracy, improving the measurement accuracy of flow velocity or flow rate. The measurement range can be expanded by reducing the measurement lower limit value.

  The first unnecessary propagation wave attenuating means includes the first sound absorbing means provided on the inner surface of the flow path wall forming the measurement flow path, and the optimal sound absorption means is disposed at an arbitrary position on the inner wall of the measurement flow path. By doing so, it is possible to efficiently attenuate unnecessary propagation waves by suppressing the generation of reflected waves without increasing the pressure loss of the fluid to be measured.

  In addition, the first unnecessary propagation wave attenuating means includes a second sound absorbing means provided in the opening hole that allows the ultrasonic transmitter / receiver to directly face the measurement flow path, and reduces the generation of unnecessary reflected waves in the opening hole. By reducing the transmission of unnecessary waves to the measurement channel, highly sensitive ultrasonic waves with excellent S / N characteristics can be transmitted and received, and the measurement accuracy can be increased.

  The first unnecessary propagation wave attenuating means is a first sound absorbing means provided on the inner surface of the flow path wall that forms the measurement flow path and a second provided in the opening hole that directly faces the ultrasonic transceiver to the measurement flow path. In addition, the transmission of unnecessary waves to the measurement channel and the unnecessary reflected waves in the measurement channel are reduced, and transmission and reception of highly sensitive ultrasonic waves with even better S / N characteristics. Measurement accuracy can be improved, and the ultrasonic transmitter / receiver can be driven at a low voltage by a battery or the like.

  In addition, the first unnecessary propagation wave attenuating means includes irregular reflection means provided on the inner surface of the flow path wall forming the measurement flow path, and an unnecessary wave outside the normal ultrasonic wave propagation path is generated in the measurement flow path. However, the unwanted waves are diffusely reflected in all directions rather than in a certain direction by the irregular reflection means provided on the inner surface of the measurement flow path, so even if some of the unwanted waves reach the receiving side, the unwanted waves are weakened by irregular reflection. Therefore, noise on the receiving side can be reduced, and highly sensitive ultrasonic waves with excellent S / N characteristics can be transmitted and received, and measurement accuracy can be improved.

  In the present embodiment, the bent portions 17 and 18 are bent in the direction of the width W of the measurement flow path 6, but the bending direction of the bent portions 17 and 18 is also the direction of the height H of the measurement flow path 6. Needless to say, it may be in any direction, and the bending directions of the bent portion 17 and the bent portion 18 may be different.

(Example 2)
A second embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a structural cross-sectional view of an ultrasonic flow rate measuring apparatus showing Embodiment 2 of the present invention, and FIG. 8 is a cross-sectional view taken along line BB of FIG. 7 and 8, the same members and functions as those of the embodiment of FIGS. 1 to 6 are denoted by the same reference numerals, detailed description thereof is omitted, and different points will be mainly described.

Reference numeral 24 denotes a flow path spacer provided on the flow path wall 7, and the ultrasonic transceivers 8 and 9 are arranged approximately at the center in the height H direction of the measurement flow path 6 by the flow path spacer 24. By providing the flow path spacer 24 on one side in the height H direction of the measurement flow path 6, the length of one flow path wall 7 a and the other flow path wall 7 b between the ultrasonic transceiver 8 and the ultrasonic transceiver 9. Is changing. Here, the propagation distance La of the ultrasonic wave on the flow path wall 7a side where the flow path spacer 24 is provided is larger than the propagation distance Lb of the ultrasonic wave on the other flow path wall 7b side (La> Lb). In addition, the difference in propagation distance is set so that the ultrasonic wave passing through the flow path wall 7a and the ultrasonic wave passing through the flow path wall 7b are attenuated by interference at the receiving side ultrasonic transceiver. That is, the difference in propagation distance is set so that a difference of half wavelength (λ / 2) occurs between the ultrasonic wave passing through the flow path wall 7a side and the ultrasonic wave passing through the flow path wall 7b (La−Lb =
λ / 2). For example, when the flow path wall 7 is formed of an aluminum-based alloy having a sound velocity V of about 5000 m / s, and the ultrasonic frequency f = 200 kHz and the propagation distance Lb = 200 mm on the flow path wall 7b side, the wavelength λ = V Therefore, the propagation distance on the channel wall 7a side should be La = 212.5 mm.

  25 is a second unnecessary propagation wave attenuating means for attenuating the ultrasonic wave propagating through the casing constituting the flow path wall 7 like the above-mentioned difference in propagation distance. The flow path wall 7 attenuates the ultrasonic waves propagating through the flow path wall 7a side and the flow path wall 7b side by interfering with each other.

  Further, the flow path spacer 24 is attached to the flow path wall 7 via a damping material (not shown), or a material such as a resin having a large attenuation of ultrasonic waves is used, so that the ultrasonic wave propagates in the flow path spacer 24. It can be difficult.

  Next, the operation of ultrasonic waves transmitted through the casing during flow rate measurement will be described in the case where the upstream ultrasonic transmitter / receiver 8 is the transmitting side and the downstream ultrasonic transmitter / receiver 9 is the receiving side. Since the ultrasonic transmitters / receivers 8 and 9 are attached to the flow path wall 7 via a support 10 that performs vibration isolation and hermetic sealing, the ultrasonic transmitter / receiver 8 on the upstream side is driven to transmit ultrasonic waves. Most of the sound waves are sent into the fluid to be measured, but some of the ultrasonic waves pass through the support 10 and leak into the flow path wall 7 which is a housing that forms the measurement flow path 6, and the receiving side super The sound wave transmitter / receiver 9 is reached. Since the sound velocity of the solid material constituting the housing is sufficiently larger than the sound velocity in the fluid to be measured such as gas or liquid, the ultrasonic wave that has passed through the housing prior to the ultrasonic wave that has passed through the original ultrasonic wave propagation path 13 It arrives at the ultrasonic transmitter / receiver on the receiving side and is received. When calculating the speed by hitting the ultrasonic wave only once, it is possible to set a delay time so that the ultrasonic wave transmitted through the housing is not received, but in order to improve the measurement accuracy, the ultrasonic wave is repeatedly sent and received many times. When performing the above, it becomes difficult to avoid the ultrasonic wave propagation wave of the ultrasonic wave hit before by the delay time. However, since the second unnecessary propagation wave attenuation means 25 is provided on the flow path wall 7 here, the unnecessary waves propagated through the flow path wall 7 interfere with each other and are attenuated by the ultrasonic transmitter / receiver 9 on the reception side. By receiving the received wave with a higher proportion of the propagation wave that has passed through the measurement flow path 6 and accurately receiving the propagation wave that has passed through the measurement flow path, the influence of the propagation wave from the housing is eliminated. High-sensitivity ultrasonic waves with excellent S / N characteristics can be transmitted and received, and the measurement accuracy of flow velocity or flow rate can be improved and the measurement range can be expanded. The same applies to the case where the downstream ultrasonic transmitter / receiver 9 is the transmitting side and the upstream ultrasonic transmitter / receiver 8 is the receiving side.

  In the present embodiment, the flow path wall 7a side and the flow path wall 7b side are formed of the same material, and only the propagation distance is changed so that a half-wavelength difference is generated in the ultrasonic wave propagating through the housing. However, by forming the flow path wall 7a side and the flow path wall 7b side from materials having different sound speeds, it is possible to produce an attenuation effect due to interference, and it is possible to reduce the external dimensions of the flow path wall by selecting the material.

  FIG. 9 is a cross-sectional view taken along the line BB showing another embodiment of the second unnecessary propagation wave attenuating means, and 26 is a vibration transmission suppressing means provided in the flow path wall 7 and extending in the direction of the ultrasonic transceivers 8 and 9. It is. The vibration transmission suppressing means 26 is made of a material having a great attenuation effect on the propagation of ultrasonic waves while being in close contact with the flow path wall 7, and the ultrasonic wave leaking from the ultrasonic transmitter / receiver on the transmission side causes the flow path wall 7 to flow. Propagating and arriving at the ultrasonic transmitter / receiver on the receiving side is prevented to act as a second unnecessary propagation wave attenuating means.

For this reason, even if an unnecessary ultrasonic wave transmitted to the housing that forms the measurement channel leaks, the unnecessary wave propagates before it reaches the ultrasonic transmitter / receiver on the receiving side. The means is further attenuated, and the ultrasonic transmitter / receiver on the receiving side eliminates unnecessary waves propagating through the casing of the measurement channel and increases the ratio of the ultrasonic component that has passed through the regular propagation channel in the measurement channel. High-sensitivity ultrasonic waves with excellent N characteristics can be transmitted and received, and propagation waves that have passed through the measurement channel can be accurately received, and the measurement accuracy of flow velocity or flow rate can be improved and the measurement range can be expanded.

  Furthermore, since this vibration transmission suppressing means 26 is arranged extending in the installation direction of the ultrasonic transmitter / receiver in the flow path wall 7, it not only attenuates ultrasonic waves leaking from the transmission side to the reception side, but also from the outside. This disturbance can be attenuated even with respect to the ultrasonic vibration and intentional disturbance vibration, and the reliability of the measurement operation against the disturbance can be enhanced.

  FIG. 10 is a sectional view taken along line BB showing another embodiment of the vibration transmission suppressing means. In FIG. 10, 27 is interposed between the upstream flow path wall 7c to which the upstream ultrasonic transceiver 8 is attached and the downstream flow path wall 7d to which the downstream ultrasonic transceiver 9 is attached. The vibration transmission suppressing means 28 is formed by connecting the upstream flow path wall 7 c and the downstream flow path wall 7 d via the vibration suppression body 27. Further, unnecessary propagation waves leaking from the transmitting-side ultrasonic transceiver to the measurement channel housing are reliably blocked by the damping unit and do not reach the receiving-side ultrasonic transmitter / receiver. This makes it possible to transmit and receive highly sensitive ultrasonic waves with excellent measurement accuracy and measurement range.

  Further, the flow path wall 7 forming the measurement flow path 6 is formed of a vibration damping material having high vibration damping properties (not shown). As this damping material, there are metal materials such as cast iron and magnesium alloy, which have better damping properties than the aluminum cast alloy that is usually used as a die-cast alloy. In particular, further weight reduction can be realized with a magnesium alloy. As described above, the configuration of the measurement channel can be simplified while maintaining the transmission / reception of high-sensitivity ultrasonic waves with excellent S / N characteristics, and the practicality is improved by reducing the size, weight and cost of the measurement channel. be able to.

  FIG. 11 is a cross-sectional view taken along the line BB showing another embodiment of the second unnecessary propagation wave attenuating means, and 29 is a sound insulating means provided on the outer surface of the flow path wall 7 forming the measurement flow path 6, This disturbance is shielded or attenuated so as not to enter the measurement channel 6 side against ultrasonic vibrations or intentional disturbances applied from the outside of the channel 6. And even if vibrations such as ultrasonic waves are applied from the outside, the disturbance vibrations are attenuated by the sound insulation means that covers the measurement flow path, and the ultrasonic transmitter / receiver can transmit and receive ultrasonic waves without the influence of disturbance vibrations. It is possible to measure the flow velocity or flow rate that is strong against the noise and improve the reliability. Furthermore, since the sound insulation means can reduce the leakage of the ultrasonic waves in the measurement channel to the outside, the influence on others can be eliminated and the installation can be improved.

  In addition, vibration transmission suppression means 28 and sound insulation means 29 are provided as second unnecessary propagation wave attenuation means. And, unnecessary waves propagating through the housing are eliminated, and the measurement accuracy is improved by transmitting and receiving highly sensitive ultrasonic waves with excellent S / N characteristics, the measurement range is expanded, and the influence of ultrasonic waves that eliminate the influence of disturbance vibrations is eliminated. It is possible to improve reliability against disturbance caused by transmission and reception, and to improve practicality.

  As another example of the sound insulation means, the sound insulation means 29 is provided with heat insulation performance (not shown). And even if an outside temperature change or a sudden change in the amount of solar radiation occurs, the temperature change of the entire measurement channel 6 is equalized, and a rapid temperature change is prevented, so that a measurement error due to a change in the sound velocity of the fluid to be measured. The measurement error due to the temperature characteristics of the ultrasonic transmitter / receiver is reduced by making the temperature of the paired ultrasonic transmitter / receiver the same, and the occurrence of condensation due to rapid or local low temperature is prevented. In addition to realizing measurement of flow velocity or flow rate that is resistant to disturbance vibrations, measurement of flow velocity or flow rate is reduced by reducing the influence on the measurement flow path such as sonic fluctuations and dew condensation caused by external heat such as solar radiation and ambient temperature changes. Accuracy reliability can be improved.

As described above, according to this embodiment, since the second unnecessary propagation wave attenuation means for attenuating the unnecessary propagation wave propagating through the housing is provided, the ultrasonic wave transmitted from the ultrasonic transmitter / receiver on the transmission side is provided. When propagating through the measurement channel to the receiving side ultrasonic transceiver, unnecessary vibration leaking into the measurement channel housing is attenuated and received by the receiving side ultrasonic transceiver. The ultrasonic transmitter / receiver eliminates the influence of the propagation wave from the measurement channel housing and enables highly sensitive transmission / reception of ultrasonic waves with excellent S / N characteristics. Can improve the accuracy of measurement of flow velocity or flow rate and expand the measurement range.

  The second unnecessary propagation wave attenuating means is provided with vibration transmission suppressing means provided between the ultrasonic transceivers of the measurement channel. And even if an unnecessary propagation wave of the ultrasonic wave transmitted to the casing forming the measurement flow channel leaks, the unnecessary propagation wave is transmitted to the ultrasonic transmission / reception unit before the vibration transmission suppressing means. Is attenuated, and the ultrasonic transmitter / receiver on the receiving side eliminates unnecessary waves propagating through the casing of the measurement flow path, and increases the ratio of the ultrasonic component that has passed through the normal propagation path in the measurement flow path. High-sensitivity ultrasonic waves with excellent characteristics can be transmitted and received, and the propagating wave that has passed through the measurement channel can be accurately received, and the measurement accuracy of flow velocity or flow rate can be improved and the measurement range can be expanded.

  Further, the second unnecessary propagation wave attenuating means is provided with sound insulation means provided on the outer surface of the flow path wall forming the measurement flow path. And even if vibrations such as ultrasonic waves are applied from the outside, the disturbance vibrations are attenuated by the sound insulation means that covers the measurement flow path, and the ultrasonic transmitter / receiver can transmit and receive ultrasonic waves without the influence of disturbance vibrations. It is possible to measure the flow velocity or flow rate that is strong against the noise and improve the reliability.

  The second unnecessary propagation wave attenuating means includes a vibration transmission suppressing means provided between the ultrasonic transceivers of the measurement flow path and a sound insulation means provided on the outer surface of the flow path wall forming the measurement flow path. is there. And, unnecessary waves propagating through the housing are eliminated, and the measurement accuracy is improved by transmitting and receiving highly sensitive ultrasonic waves with excellent S / N characteristics, the measurement range is expanded, and the influence of ultrasonic waves that eliminate the influence of disturbance vibrations is eliminated. It is possible to improve reliability against disturbance caused by transmission and reception, and to improve practicality.

  Further, the vibration transmission suppressing means connects the upstream flow path wall where the upstream ultrasonic transceiver is arranged and the downstream flow path wall where the downstream ultrasonic transceiver is arranged via a damping body. Is. And since the unnecessary wave leaking from the ultrasonic transmitter / receiver on the transmission side to the casing of the measurement flow path is blocked by the damping body and does not reach the ultrasonic transmitter / receiver on the reception side, the S / N characteristic is further improved. High-sensitivity ultrasonic waves can be transmitted and received, and measurement accuracy and measurement range can be further improved.

  Further, the second unnecessary propagation wave attenuating means is one in which the channel wall of the measurement channel is formed of a damping material. In addition, the configuration of the measurement channel can be simplified while maintaining transmission / reception of highly sensitive ultrasonic waves with excellent S / N characteristics, and the practicality can be improved by reducing the size, weight and cost of the measurement channel. it can.

  Further, the sound insulation means has a heat insulating performance. In addition to realizing measurement of flow velocity or flow rate that is resistant to disturbance vibrations, measurement of flow velocity or flow rate is reduced by reducing the influence on the measurement flow path such as sonic fluctuations and dew condensation caused by external heat such as solar radiation and ambient temperature changes. Accuracy reliability can be improved.

(Example 3)
FIG. 12 is a structural cross-sectional view of an ultrasonic flow rate measuring apparatus showing Embodiment 3 of the present invention. In FIG. 12, the same members and functions as those in the embodiment of FIGS. 1 to 11 are denoted by the same reference numerals, detailed description thereof will be omitted, and different points will be mainly described.

Reference numeral 30 denotes an inlet block that is connected to the upstream side of the bent portion 17 and has a communication port 31 that opens to the measurement flow path 6. The inlet block 30 is provided with an on-off valve 34 having a valve body 33 that faces the valve seat 32. It has been. Reference numeral 35 denotes an inlet side connection port which is provided on the upstream side of the valve seat 32 and is connected to an external pipe (not shown) and into which fluid flows. Reference numeral 36 denotes an outlet block provided in communication with the downstream side of the bent portion 18, and the outlet block 36 has an outlet-side connection port 37 through which fluid flows out and is connected to an external pipe (not shown). . Reference numeral 38 denotes a spring that urges the valve body 33 in the direction of the valve seat 32, and reference numeral 39 denotes a drive unit such as a solenoid or a motor that drives the valve body 33 to open or close. Reference numeral 40 denotes a third unnecessary propagation wave attenuating means which is provided in contact with the outer peripheral portion so as to cover the inlet block 30 and is formed of a damping material, and 41 is in contact with the outer peripheral portion so as to cover the outlet block 36. And a third unnecessary propagation wave attenuating means formed of a damping material. These third unnecessary propagation wave attenuating means 40 and 41 are used to measure vibrations or ultrasonic waves that enter from external pipes (not shown) connected to the inlet-side or outlet-side connection ports 35 and 37 and cause disturbance. Propagation to the path 6 is attenuated.

  Next, the operation will be described. When this flow measuring device is installed in parallel, for example, when installed adjacent to a short distance, such as a home gas meter, the ultrasonic vibration for measurement in the adjacent gas meter propagates through the pipe. However, the disturbance vibration is attenuated by the third unnecessary propagation wave attenuating means 40 provided on the entrance side, so that the propagation to the measurement channel 6 can be reduced, and the ultrasonic transducer on the reception side has a high sensitivity with reduced noise components. Can receive high-accuracy ultrasonic waves and measure the flow rate with high accuracy. Further, even when abnormal vibration is applied to the external piping, the third unnecessary propagation wave attenuating means 40, 41 provided on the inlet side or the outlet side can reduce the intrusion of disturbance vibration into the measurement flow path 6, Highly reliable measurement can be performed. In addition, the ultrasonic vibration in the measurement channel can be prevented from leaking to the outside pipe side, and it is difficult to receive disturbance from the outside pipe, so there are no restrictions on the installation position and installation distance, improving the degree of freedom of installation. it can. Here, the example in which the valve is built in the inlet block has been described, but it goes without saying that the same applies to the case where the inlet block has no valve like the outlet block.

  In this way, external disturbances such as external vibration waves (for example, ultrasonic vibration waves of other ultrasonic flow measurement devices installed nearby in the piping system) via external piping connected to the connection port are attenuated. Therefore, it is possible to receive highly sensitive ultrasonic waves with excellent S / N characteristics, and to accurately receive the propagation wave that has passed through the measurement flow path. Improvement and expansion of the measurement range are possible, and it can be installed at any position regardless of other ultrasonic flow rate measuring devices, so the degree of freedom of installation is high and convenience can be improved.

  FIG. 13 is a sectional view showing another configuration of the third embodiment of the unnecessary propagation wave attenuating means. The same members and the same functions as those of the embodiment of FIG. However, the explanation will be focused on. In FIG. 13, reference numeral 42 denotes external vibration suppression means interposed between the inlet side connection port 35 and the measurement flow path 6. The flow path wall 7 and the inlet block 30 forming the measurement flow path 6 are connected to this external vibration. They are connected with the suppression means 42 in between. Reference numeral 43 denotes external vibration suppression means interposed between the outlet-side connection port 37 and the measurement flow path 6. The flow path wall 7 and the outlet block 36 forming the measurement flow path 6 are connected to the external vibration suppression means 43. Connected with a gap between them. These external vibration suppressing means 42 and 43 are formed of a damping material having excellent vibration damping characteristics, thereby forming third unnecessary propagation wave damping means.

  For this reason, the vibration or ultrasonic wave applied to the external pipe is prevented from propagating to the measurement flow path 6 by the external vibration suppression means 42 and 43. Therefore, the disturbance via the external pipe connected to the connection port is blocked by the external vibration suppressing means to prevent the entry into the measurement flow path, and the disturbance noise that has entered from the connection port is further reduced and the S / N is reduced. Due to the characteristics, it is possible to receive high-sensitivity ultrasonic waves with excellent characteristics, and it is possible to accurately receive the propagation wave that has passed through the measurement flow path, and to improve the measurement accuracy and measurement range of flow velocity or flow rate.

  Further, by providing both the above-described third unnecessary propagation wave attenuating means 40 and 41 and the external vibration suppressing means 42 and 43 as the third unnecessary propagation wave attenuating means, the unnecessary propagation waves are further attenuated, and the measurement accuracy and The measurement range can be further improved.

  As another embodiment of the third unnecessary propagation wave attenuating means, the inlet block or the outlet block connected to the upstream side or the downstream side of the channel wall forming the measurement channel is formed of a damping material. It is a thing. With this configuration, the inlet block and the outlet block can be isolated from each other in vibration transmission between the external pipe and the flow path wall forming the measurement flow path, so that it is stable regardless of disturbance and has high S / N characteristics. As a result, it is possible to reduce the size, weight and cost of the apparatus by simplifying the configuration of the inlet block or outlet block. In addition, the configuration of the measuring device can be simplified while reducing the disturbance noise that has entered from the connection port and maintaining the transmission / reception of highly sensitive ultrasonic waves with excellent S / N characteristics, and the measuring device can be reduced in size, weight, and cost. Practicality can be improved by the conversion.

  As another embodiment of the third unnecessary propagation wave attenuating means, the third unnecessary propagation wave attenuating means 40, 41 or the external vibration suppressing means 42, 43 are provided with heat insulation performance. For this reason, it is possible to prevent sudden changes in the temperature of the measurement flow path due to solar radiation applied to the external pipes connected to the connection ports 35 and 37 and changes in the outside air temperature and the occurrence of uneven temperature distribution, and the temperature of the ultrasonic transceiver Measurement accuracy can be stabilized by reducing the occurrence of errors due to characteristics. And the influence on the measurement flow path by the heat from the outside, such as the solar radiation which entered into the connection port or the measurement apparatus, and the external temperature change, can be reduced, and the reliability of the measurement accuracy of the flow velocity or the flow rate can be improved.

  As described above, according to the present embodiment, the third unnecessary propagation wave attenuating means for attenuating the disturbance vibration that has entered from the external pipe is provided, so that an external pipe via the external pipe connected to the connection port is provided. Attenuating disturbances such as vibration waves (for example, ultrasonic vibration waves of other ultrasonic flow measurement devices installed nearby in the piping system) to reduce the arrival at the ultrasonic transmitter / receiver and have excellent S / N characteristics High-sensitivity ultrasonic waves can be received, and the propagation waves that have passed through the measurement channel can be received accurately, the measurement accuracy of flow velocity or flow rate can be improved and the measurement range can be expanded. Since it can be installed in any position, it can be installed with a high degree of freedom and convenience.

  In addition, the third unnecessary propagation wave attenuating means includes an external vibration suppressing means interposed between the connection port and the flow channel wall forming the measurement flow channel, so that an external pipe connected to the connection port is provided. Disturbances that pass through are blocked by external vibration suppression means to prevent intrusion into the measurement flow path, disturbance noise that has entered through the connection port is further reduced, and high-sensitivity ultrasonic waves can be received with excellent S / N characteristics. It becomes possible to accurately receive the propagation wave that has passed through the measurement flow path, and the measurement accuracy and measurement range of the flow velocity or flow rate can be further improved.

  In addition, since the third unnecessary propagation wave attenuating means is provided with an inlet block or an outlet block formed of a damping material on the upstream side or downstream side of the measurement flow path, the disturbance noise entering from the connection port is reduced and the S / S The configuration of the measuring device can be simplified while maintaining transmission / reception of highly sensitive ultrasonic waves with excellent N characteristics, and the practicality can be improved by reducing the size, weight and cost of the measuring device.

  In addition, the third unwanted propagation wave attenuating means has a heat insulation performance, so the influence on the measurement channel due to external heat, such as solar radiation entering the measurement port or changes in the outside air temperature. This can reduce the reliability of the measurement accuracy of flow velocity or flow rate.

Example 4
FIG. 14 is a structural cross-sectional view of an ultrasonic flow rate measuring apparatus showing Embodiment 4 of the present invention. In FIG. 14, the same members and functions as those of the embodiment of FIGS. 1 to 13 are denoted by the same reference numerals, detailed description thereof will be omitted, and different points will be mainly described.

The measurement flow path 6 is provided with a first sound absorbing means 15 serving as a first unnecessary propagation wave attenuation means 14, and an upstream ultrasonic transmitter / receiver 8 is attached to the flow path wall 7 forming the measurement flow path 6. The second unnecessary propagation wave attenuating means 25 by the damping body 27 interposed between the upstream flow path wall 7c and the downstream flow path wall 7d to which the downstream ultrasonic transceiver 9 is attached. Further, the third unnecessary propagation wave attenuating means 40 or 41 is provided in the inlet block 30 or the outlet block 36 provided with a connection port 35 or 37 for connecting an external pipe (not shown).

  Therefore, when the flow velocity is measured between the ultrasonic transmitters / receivers 8 and 9 by transmitting / receiving ultrasonic waves, the ultrasonic waves deviating from the ultrasonic propagation path 13 are absorbed by the first unnecessary propagation wave attenuation means 14 as described above. The ultrasonic vibration leaked from the transmitting-side ultrasonic transmitter / receiver 8 or 9 to the flow path wall 7 is attenuated by the second unnecessary propagation wave attenuating means 25 formed by the damping body 27 and is superposed on the receiving side. The ultrasonic wave transmitter / receiver 8 or 9 is no longer affected as a noise component, and the ultrasonic wave transmitter / receiver 8 or 9 on the receiving side has higher S / N characteristics due to the normal propagation wave that has passed through the ultrasonic wave propagation path 13 and has higher sensitivity. Are sent and received. Furthermore, even if vibration that becomes a noise component is applied to the external pipe, the unnecessary vibration wave is attenuated by the third unnecessary propagation wave attenuation means 40 or 41 and does not affect the measurement flow path 6, so that stable flow rate measurement is possible. It can be executed with or without disturbance. Needless to say, when the sound insulation means 29 provided on the outer surface of the flow path wall 7 described above with reference to FIG. 11 is provided as the second unnecessary propagation wave attenuation means, it is possible to be strong against disturbances other than external piping. .

  In this way, even when a disturbance is applied, the third unnecessary propagation wave attenuating means reduces the propagation of the vibration wave due to the disturbance to the measurement channel, and it is unnecessary to leak to the channel wall forming the measurement channel Vibration is attenuated by the second unnecessary propagation wave attenuating means before reaching the reception-side ultrasonic transmitter / receiver, and further, the first unnecessary propagation wave attenuation means in the reception-side ultrasonic transmitter / receiver in the measurement channel. The ratio of the normal propagation wave that has passed through the normal propagation path can be increased and received, detection of the received waveform with less noise component can be performed, and high-sensitivity ultrasonic waves with excellent S / N characteristics can be transmitted and received. The flow rate or flow rate measurement accuracy can be further improved by measuring the flow rate with higher accuracy, and the measurement range can be further expanded by increasing the measurable flow velocity or flow rate upper limit value or reducing the measurement lower limit value. That. Furthermore, it is possible to realize a flow rate measuring device that is resistant to disturbance, and the degree of freedom of the installation position of other flow rate measuring devices is increased, thereby improving the installation property.

(Example 5)
FIG. 15 is a structural cross-sectional view of an ultrasonic flow rate measuring apparatus showing Embodiment 5 of the present invention. In FIG. 15, the same members and functions as those of the embodiment of FIGS. 1 to 14 are denoted by the same reference numerals, detailed description thereof will be omitted, and different points will be mainly described.

  The measurement flow path 6 is provided with a first sound absorbing means 15 serving as a first unnecessary propagation wave attenuation means 14, and an upstream ultrasonic transmitter / receiver 8 is attached to the flow path wall 7 forming the measurement flow path 6. The second unnecessary propagation wave attenuating means 25 by the damping body 27 interposed between the upstream flow path wall 7c and the downstream flow path wall 7d to which the downstream ultrasonic transceiver 9 is attached; A second unnecessary propagation wave attenuating means 25 is provided by a sound insulating means 29 provided on the outer surface of the flow path wall 7. As described above, the second unnecessary propagation wave attenuating means 25 includes the vibration damping body 27 interposed in the flow path wall 7 and the sound insulation means 29 on the outer surface of the flow path wall 7, so that the While suppressing the noise component due to the sound wave vibration, the normal propagation wave propagated through the ultrasonic propagation path 13 by the first unnecessary propagation wave attenuation means 14 can be received with high sensitivity. In particular, by providing the sound insulation means 29 on the outer surface of the flow path wall 7 as the second unnecessary propagation wave attenuating means 25, a device that is resistant to disturbances such as unnecessary vibrations from the outside of the measurement flow path 6 can be realized, and is practical. Can be increased.

For this reason, the unnecessary vibration leaking to the flow path wall forming the measurement flow path is attenuated by the second unnecessary propagation wave attenuating means before reaching the reception-side ultrasonic transceiver, and further the first unnecessary propagation wave The receiving side ultrasonic transmitter / receiver can increase the ratio of the normal propagation wave that has passed through the normal propagation path by the attenuation means, detect the reception waveform with few noise components, and has high sensitivity with excellent S / N characteristics. The ultrasonic wave can be transmitted and received more accurately and the propagation time can be measured with higher accuracy, so that the measurement accuracy of the flow velocity or flow rate can be further improved, and the measurement upper limit value of flow velocity or flow rate can be increased or the measurement lower limit value can be reduced. The measurement range can be further expanded.

(Example 6)
FIG. 16 is a sectional view showing the configuration of an ultrasonic flow rate measuring apparatus according to Embodiment 6 of the present invention. In FIG. 16, the same members and functions as those of the embodiment of FIGS. 1 to 15 are denoted by the same reference numerals, detailed description thereof is omitted, and different points will be mainly described.

  The measurement flow path 6 is provided with a first sound absorbing means 15 as the first unnecessary propagation wave attenuation means 14, and the inlet block 30 or the outlet block 36 is provided with third unnecessary propagation wave attenuation means 40 or 41. The external vibration suppressing means 42 interposed between the connection port 35 of the inlet block 30 and the flow channel wall 7 forming the measurement flow channel 6, and the flow forming the measurement flow channel 6 with the connection port 37 of the outlet block 36. External vibration suppressing means 43 interposed between the road wall 7 and the third unnecessary propagation wave attenuating means 40, 41. As described above, since the third unnecessary propagation wave attenuating means 40 and 41 are provided, unnecessary vibration that has propagated through an external pipe (not shown) is transmitted to the flow path wall 7 that forms the measurement flow path 6. The ultrasonic vibration transmitted from the ultrasonic transmitter / receiver 8 or 9 is prevented from leaking to the external pipe (not shown) side, and this flow measuring device is adjacent. Can be arranged in parallel. Further, the first unnecessary propagation wave attenuating means 14 can transmit and receive the normal propagation wave propagated through the ultrasonic propagation path 13 with high sensitivity, so that the measurement accuracy can be improved and the measurement range can be expanded.

  For this reason, even when a disturbance or the like is added, the third unnecessary propagation wave attenuating means reduces the propagation of the vibration wave due to the disturbance to the measurement channel, and the first unnecessary propagation wave attenuating means further reduces the ultrasonic wave on the receiving side. Since the transmitter / receiver can receive the signal with a higher ratio of the normal propagation wave that has passed through the normal propagation path, it can detect the received waveform with less noise component and transmit / receive highly sensitive ultrasonic waves with excellent S / N characteristics. Therefore, it is possible to further improve the measurement accuracy of the flow velocity or flow rate by measuring the propagation time with higher accuracy, and further expand the measurement range by expanding the measurement upper limit value of the flow velocity or flow rate or reducing the measurement lower limit value. Can do. Furthermore, it is possible to realize a flow rate measuring device that is resistant to disturbance, and the degree of freedom of the installation position of other flow rate measuring devices is increased, thereby improving the installation property.

(Example 7)
FIG. 17 is a structural cross-sectional view of an ultrasonic flow rate measuring apparatus showing Embodiment 7 of the present invention. In FIG. 17, the same members and functions as those of the embodiment of FIGS. 1 to 16 are denoted by the same reference numerals, detailed description thereof is omitted, and different points will be mainly described.

  On the flow path wall 7 forming the measurement flow path 6, the upstream flow path wall 7 c to which the upstream ultrasonic transceiver 8 is attached and the downstream flow path to which the downstream ultrasonic transceiver 9 is attached. A second unnecessary propagation wave attenuating means 25 by a damping body 27 interposed between the wall 7d and a second unnecessary propagation wave attenuating means 25 by a sound insulation means 29 provided on the outer surface of the flow path wall 7 are provided. The block 30 or the outlet block 36 is provided with third unnecessary propagation wave attenuating means 40 or 41, and is interposed between the connection port 35 of the inlet block 30 and the flow path wall 7 forming the measurement flow path 6. External vibration suppression means 42 and external vibration suppression means 43 interposed between the connection port 37 of the outlet block 36 and the flow path wall 7 forming the measurement flow path 6 are connected to the third unnecessary propagation wave attenuation means 40, 41 is provided.

For this reason, unnecessary ultrasonic waves such as ultrasonic vibrations leaked from the transmitting-side ultrasonic transmitter / receiver or disturbance vibrations that have entered from external pipes are not necessary for the second unnecessary propagation wave attenuation means 25 or the third unnecessary propagation wave attenuation means. It is further attenuated by 40 and 41, and the reliability with respect to disturbance can be improved without adversely affecting the ultrasonic transceiver on the receiving side. Further, the vibration of the ultrasonic wave transmitted from the ultrasonic transmitter / receiver 8 or 9 is prevented from leaking to the external pipe (not shown) side, so that the flow measuring device can be arranged adjacently in parallel. become. Further, by providing heat insulation performance to the sound insulation means 29 and the third unnecessary propagation wave attenuation means 40 and 41, which are the second unnecessary propagation wave attenuation means 25, the change in the ambient temperature and the amount of solar radiation hitting the flow rate measuring device can be reduced. A stable and highly reliable flow rate measurement can be performed by gradually changing the temperature change rate of the flow rate measuring unit 6 in response to a sudden change, and a device that is resistant to changes in the thermal environment can be realized.

  In this way, even when a disturbance is applied, the third unnecessary propagation wave attenuation means reduces the propagation of the vibration wave due to the disturbance to the measurement channel, and the channel wall casing that forms the measurement channel Leaked unnecessary vibration is attenuated by the second unnecessary propagation wave attenuation means before reaching the reception-side ultrasonic transmitter / receiver, and the reception-side ultrasonic transmitter / receiver reduces the influence of the propagation wave from the measurement channel housing. By eliminating the received waveform with less noise components, it is possible to send and receive highly sensitive ultrasonic waves with excellent S / N characteristics, and to measure the propagation time even more accurately, thereby measuring the flow velocity or flow rate. Can be further improved, and the measurement range can be further expanded by increasing the measurement upper limit value or reducing the measurement lower limit value of the measurable flow velocity or flow rate. Furthermore, it is possible to realize a flow rate measuring device that is resistant to disturbance, and the degree of freedom of the installation position of other flow rate measuring devices is increased, thereby improving the installation property.

6 Measurement channel 8, 9 Ultrasonic transmitter / receiver 14 First unnecessary propagation wave attenuating means 15, 21 First sound absorbing means 19 Measurement control part 20 Calculation part 22 Second sound absorbing means 23 Diffuse reflection means 25 Second unnecessary propagation Wave attenuation means 26, 28 Vibration transmission suppression means 27 Damping body 29 Sound insulation means 35, 37 Connection port 40, 41 Third unnecessary propagation wave attenuation means 42, 43 External vibration suppression means

Claims (11)

A measurement channel through which the fluid to be measured flows, an ultrasonic transmitter / receiver provided in the measurement channel, and a second unnecessary propagation that attenuates unnecessary propagation waves of ultrasonic waves propagating through the channel wall forming the measurement channel A second unnecessary propagation, comprising: a wave attenuating means; a measurement control unit for measuring an ultrasonic propagation time between the ultrasonic transceivers; and a calculation unit for calculating a flow rate based on a signal from the measurement control unit. The ultrasonic wave flow measuring device includes a vibration transmission suppressing means provided inside the flow path wall between the ultrasonic transceivers of the measurement flow path. The ultrasonic flow rate measuring device according to claim 1, further comprising a first unnecessary propagation wave attenuation unit that attenuates an unnecessary propagation wave of the ultrasonic wave propagating in the measurement flow path. The super-portion according to claim 1 or 2, further comprising: a connection port that communicates with the measurement flow path and is connected to an external pipe; and third unnecessary propagation wave attenuation means that attenuates disturbance vibration that has entered from the external pipe. Sonic flow measuring device. The ultrasonic flow rate measuring device according to claim 1, wherein the second unnecessary propagation wave attenuating means includes a sound insulating means provided on an outer surface of a flow path wall forming a measurement flow path. The ultrasonic flow rate measuring device according to claim 1, wherein the vibration transmission suppression unit is arranged to be extended in an installation direction of the ultrasonic receiver in the flow path wall. The vibration transmission suppressing means connects an upstream flow path wall where an upstream ultrasonic transceiver is arranged and a downstream flow path wall where a downstream ultrasonic transceiver is arranged via a damping body. The ultrasonic flow measuring device according to claim 1. The ultrasonic flow rate measuring device according to claim 1, wherein the second unnecessary propagation wave attenuating means has a channel wall of a measurement channel formed of a damping material. The ultrasonic flow rate measuring device according to claim 4, wherein the sound insulating means has a heat insulating performance. The ultrasonic flow rate measuring device according to claim 3, wherein the third unnecessary propagation wave attenuating means includes an external vibration suppressing means interposed between the connection port and the flow path wall forming the measurement flow path. The ultrasonic flow rate measuring device according to claim 3, wherein the third unnecessary propagation wave attenuating means includes an inlet block or an outlet block formed of a damping material on an upstream side or a downstream side of the measurement channel. The ultrasonic flow rate measuring device according to any one of claims 3, 9, and 10, wherein the third unnecessary propagation wave attenuating means has a heat insulation performance.