TWI794112B - Ultrasonic flow measurement device, controller therefor and ultrasonic flow measuring method - Google Patents

Abstract

An ultrasonic flow measurement device, a controller therefor, and an ultrasonic flow measuring method are disclosed. A controller for an ultrasonic flow measurement device in which a pair of ultrasonic sensors is disposed at least one side of a measuring tube through which fluid flows, includes a plurality of switches respectively connected to the pair of ultrasonic sensors to turn on or off a signal receiving path for transmitting a receiving signal; a noise canceling unit to cancel noise of the receiving signal transmitted to the signal receiving path; a time-to-digital converter to output a digital code corresponding to a time difference between a receiving time of the receiving signal from which the noise has been canceled and a transmitting time of a transmission signal; and a control unit to receive two digital codes output respectively during forward signal transmission and reverse signal transmission with respect to a moving direction of the fluid, and to calculate a flow velocity and a flow rate of the fluid using the received two digital codes.

Description

Ultrasonic flow measuring device, controller used therefor, and ultrasonic flow measuring method

This embodiment relates to an ultrasonic flow measuring device suitable for small-diameter pipelines, a controller used therein, and an ultrasonic flow measuring method.

Transit-time ultrasonic flowmeters place two piezoelectric ultrasonic sensors with specific resonant frequencies in the pipeline through which the fluid flows, and transmit and receive ultrasonic signals between the two piezoelectric ultrasonic sensors. A device for measuring the velocity and flow of a fluid.

These conventional ultrasonic flowmeters are used in various fields such as various industrial sites.

However, in the case of small-diameter or low-flow pipes, the ultrasonic measurement method has the problem of no measurement or measurement error because of the short distance between ultrasonic sensors, or the small difference in ultrasonic passing time due to low flow velocity .

Therefore, it is necessary to develop a flow measurement device suitable for small diameter pipelines.

This embodiment can provide an ultrasonic flow measuring device suitable for small-diameter pipelines, a controller used therein, and an ultrasonic flow measuring method.

According to one embodiment, the controller for the ultrasonic flow measuring device, wherein a pair of ultrasonic sensors are arranged on at least one side of the measuring tube through which the fluid flows, the controller may include: a plurality of switches connected to The pair of ultrasonic sensors is used to open or close the signal receiving path used to transmit the received signal, and is used to transmit the transmitted signal; the noise canceling unit is used to eliminate the noise of the received signal transmitted to the signal receiving path; the time digit a converter outputting a digital code corresponding to the time difference between the reception time of the received signal and the transmission time of the transmitted signal from which the noise is eliminated; Two digital codes are respectively output during forward signal transmission and reverse signal transmission, and the flow velocity and flow rate of the fluid are calculated using the two received digital codes.

The plurality of switches may include a first switch and a second switch, and the first switch may be connected to a signal receiving path between any one of the pair of ultrasonic sensors and the time-to-digital converter, and in relation to the The signal receiving path is closed during the forward signal transmission of the moving direction of the fluid, and the second switch can be connected to the signal receiving between the other of the pair of ultrasonic sensors and the time-to-digital converter. path, and closes the signal receiving path during the reverse signal transmission relative to the moving direction of the fluid.

The switch may comprise a T/R (transmit/receive) switch.

The control unit can be calculated by excluding the ratio of the transit distance (transit distance) of the area between the ultrasonic sensor and the measuring tube to the transit distance of the ultrasonic signal between the two ultrasonic sensors, to correct the passage time corresponding to the digital code, and use the corrected passage time to calculate the flow velocity and the flow rate of the fluid.

、

獲得，在該反向訊號發射的期間的該通過時間可由方程式

、

獲得，c可為該流體的聲速，v可為該流體的平均速度，L可為該兩個超音波感測器之間的該超音波訊號的該通過距離，L'可為不包括該超音波感測器與該測量管之間的區域的該通過距離，而θ可為該超音波感測器的傾角。 The transit time during the transmission of the forward signal can be given by the equation

,

Obtained, the transit time during the transmission of the reverse signal can be obtained by the equation

,

Obtained, c can be the speed of sound of the fluid, v can be the average velocity of the fluid, L can be the passing distance of the ultrasonic signal between the two ultrasonic sensors, and L' can be excluding the ultrasonic The passing distance of the area between the acoustic sensor and the measuring tube, and θ can be the inclination angle of the ultrasonic sensor.

得到，而在該反向訊號發射過程中，該第二通過時間由方程式

得到，c為該流體的聲速，v為該流體的平均速度，L為該兩個超音波感測器之間的該超音波訊號的該通過距離，而θ是該超音波感測器的傾角。 The control unit can calculate the first passing time corresponding to the digital code and the second passing time calculated by the equation, and correct the first passing time by the calculated average value. During the transmission of the forward signal, the second transit time is given by the equation

obtained, and during the reverse signal transmission process, the second transit time is given by the equation

Obtain, c is the speed of sound of the fluid, v is the average velocity of the fluid, L is the passing distance of the ultrasonic signal between the two ultrasonic sensors, and θ is the inclination angle of the ultrasonic sensor .

The noise cancellation unit may include a low noise amplifier (LNA).

According to one embodiment, the ultrasonic flow measuring device may comprise a measuring tube through which fluid flows; a pair of ultrasonic sensors arranged on at least one side of the measuring tube; and a control part connected to the measuring tube, the control part It includes the controller according to any one of claims 1-3 and 5 and a casing for accommodating the controller.

The ultrasonic flow measuring device may further include a connecting pipe, which connects the measuring pipe and the control part, and a cable for electrically connecting the pair of ultrasonic sensors and the controller is arranged in the connecting pipe.

According to an embodiment, the ultrasonic flow measurement method of the ultrasonic flow measurement device, the ultrasonic flow measurement device includes a time-to-digital converter to measure the transit time between a pair of ultrasonic sensors, the pair of ultrasonic sensors The detector is arranged on at least one side of the measuring tube through which the fluid flows, and may include the following steps: by emitting an ultrasonic signal in a forward direction relative to the moving direction of the fluid, measuring the ultrasonic wave by the time-to-digital converter forward transit time of the signal; by transmitting the ultrasonic signal in the reverse direction, the reverse transit time of the ultrasonic signal is measured by the time-to-digital converter; using the measured forward transit time and reverse The flow rate and flow rate of the fluid are calculated by time.

、

來獲得，c可為該流體的聲速，v可為該流體的平均速度，L可為該兩個超音波感測器之間的該超音波訊號的該通過距離，L'可為不包括該超音波感測器與該測量管之間的區域的該通過距離，而θ可為該超音波感測器的傾角。 In the step of measuring the forward transit time, the forward transit time measured by the time-to-digital converter can be corrected by the equation, and during the forward signal transmission, the forward transit time can be calculated by the equation

,

To obtain, c can be the speed of sound of the fluid, v can be the average velocity of the fluid, L can be the passing distance of the ultrasonic signal between the two ultrasonic sensors, and L' can be excluding the The passing distance of the area between the ultrasonic sensor and the measuring tube, and θ can be the inclination angle of the ultrasonic sensor.

、

來獲得，c可為該流體的聲速，v可為該流體的平均速度，L可為該兩個超音波感測器之間的該超音波訊號的該通過距離，L'可為不包括該超音波感測器與該測量管之間的區域的該通過距離，而θ可為該超音波感測器的傾角。 In the step of measuring the reverse transit time, the reverse transit time measured by the time-to-digital converter can be corrected by the equation, and during the reverse signal transmission, the reverse transit time can be calculated by the equation

,

To obtain, c can be the speed of sound of the fluid, v can be the average velocity of the fluid, L can be the passing distance of the ultrasonic signal between the two ultrasonic sensors, and L' can be excluding the The passing distance of the area between the ultrasonic sensor and the measuring tube, and θ can be the inclination angle of the ultrasonic sensor.

得到，c可為該流體的聲速，v可為該流體的平均速度，L為該兩個超音波感測器之間的該超音波訊號的該通過距離，而θ可為該超音波感測器的傾角。 In the step of measuring the forward transit time, the average value of the forward transit time measured by the time-to-digital converter and the transit time calculated by the equation can be calculated, and the forward transit time can be calculated by Corrected by the average value, in the forward signal transmission process, the transit time can be obtained by the equation

Obtain, c can be the speed of sound of the fluid, v can be the average velocity of the fluid, L is the passing distance of the ultrasonic signal between the two ultrasonic sensors, and θ can be the ultrasonic sensor inclination angle of the device.

得到，c可為該流體的聲速，v可為該流體的平均速度，L為該兩個超音波感測器之間的該超音波訊號的該通過距離，而θ可為該超音波感測器的傾角。 In the step of measuring the reverse transit time, the average value of the reverse transit time measured by the time-to-digital converter and the transit time calculated by the equation can be calculated, and the reverse transit time can be calculated by Corrected by the average value, during the reverse signal transmission, the transit time can be given by the equation

Obtain, c can be the speed of sound of the fluid, v can be the average velocity of the fluid, L is the passing distance of the ultrasonic signal between the two ultrasonic sensors, and θ can be the ultrasonic sensor inclination angle of the device.

According to one embodiment, a switch and an LNA are provided on the signal receiving path connected to the ultrasonic sensor, the switch is closed when the signal is transmitted, and the switch is opened when the signal is received, so that when a weak signal is received, the overall sensitivity of the receiver can be increased and noise can be reduced.

According to an embodiment, since the overall sensitivity of the receiver can be increased and the noise reduced, it is possible to reduce the error rate of the measurement value.

According to the embodiment, when high voltage noise generated by an external factor is received as a signal in the form of a shock wave, the switch is operated to protect the internal circuit and it is possible to stabilize the measurement.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

However, the technical concept of the present invention is not limited to some embodiments to be described, but can be implemented in various forms, and within the scope of the technical concept of the present invention, one or more elements can be selectively combined and replaced to used between examples.

In addition, terms (including technical and scientific terms) used in the embodiments of the present invention will be commonly understood by those of ordinary skill in the art to which the present invention belongs unless clearly defined and described. Commonly used terms, such as terms defined in dictionaries, may be interpreted in consideration of the contextual meaning of the relevant technical field.

In addition, the terms used in the embodiments of the present invention are used to describe the embodiments, and are not used to limit the present invention.

In this specification, the singular form may also include the plural form, unless it is specifically stated in the text, if it is described as "A and/and at least one (or more than one) of B and C", it may include a One or more of all combinations of , B and C.

In addition, terms such as first, second, A, B, (a) and (b) may be used in describing constituent elements of the embodiment of the present invention.

These terms are only used to separate a constituent element from other constituent elements, and do not limit the nature, order or sequence of the constituent elements with the terms.

Also, if an element is described as being "connected," "coupled" or "contacting" another element, the element is directly connected, coupled or contacting the other element. Also, a case of being "connected", "coupled" or "contacting" due to another component between the component and another component may be included.

Furthermore, when described as being formed or placed on the "top (top) or bottom (bottom)" of each component, the top (top) or bottom (bottom) includes not only the case where the two components are in direct contact, but also A condition in which one or more other components are formed or disposed between two components. In addition, when expressed as "top (top) or bottom (bottom)", not only the meaning of upward direction but also the meaning of downward direction based on one component may be included.

One embodiment proposes a new concept, in which the signal transmission path and the signal reception path are respectively connected to the ultrasonic sensor, and a switch is arranged on the signal reception path, so that the switch is closed when the signal is sent, and the signal is received when the signal is received. The switch is on.

1a to 1f are views showing an ultrasonic flow rate measuring device according to an embodiment of the present invention.

Referring to FIGS. 1a and 1b , an ultrasonic flow measuring device according to an embodiment of the present invention may include a measuring tube 100 through which fluid flows, an ultrasonic sensor 200 , a control unit 300 and a connecting tube 400 .

The measuring tube 100 is formed in a cylindrical shape so that fluid can flow through an internal flow path. The measuring tube 100 is, for example, inserted into and connected to the middle of the water and sewage pipe and connected to the pipe inside the water and sewage pipe, and the diameter of the pipe and the diameter of the flow path in the measuring tube 100 may be the same.

The measuring tube 100 may include a main body 110 , a fixing part 120 , a coupling part 130 and a cover 140 . The main body part 110 is formed in a cylindrical shape and has a flow path through which fluid flows, and the fixing part 120 has a pair formed on one side or both sides of the main body part 110, and a pair of ultrasonic sensors 200 are provided on the fixing part. 110 , a pair of coupling parts 130 are formed at both ends of the body part 110 and connected to the pipe, and a cover 140 is coupled to the pair of fixing parts 120 to seal the inside of each fixing part 120 . In addition, the fixing part 120 may have a connection hole 100a through which a cable for connecting the ultrasonic sensor 200 and the control part 300 is inserted at one side thereof.

In addition, the material of the measuring tube 100 may include synthetic resin and metal. At this time, the main body part 110 , the fixing part 120 and the coupling part 130 constituting the measuring tube 100 may be integrally formed.

The ultrasonic sensor 200 can be arranged obliquely and coupled to one or both sides of the measuring tube 100 , and includes a pair for sending and receiving ultrasonic signals to the fluid flowing in the flow path inside the measuring tube 100 . That is, the ultrasonic sensor 200 may include a first ultrasonic sensor 200a and a second ultrasonic sensor 200b. The first ultrasonic sensor 200a can emit ultrasonic signals and the second ultrasonic sensor 200b can receive ultrasonic signals, or the second ultrasonic sensor 200b can emit ultrasonic signals and the first ultrasonic sensor 200a can receive ultrasonic signals.

At this time, the ultrasonic sensor 200 may be disposed at a predetermined distance from the flow path inside the measuring tube 100 . The transit distance of the ultrasonic signal can be increased by the separation distance.

The control part 300 can be connected to the pair of ultrasonic sensors 200 installed in the measuring tube 100, and by receiving ultrasonic signals from the pair of ultrasonic sensors 200 and using the transit time difference of the emitted ultrasonic signals, The flow velocity and flow rate of the fluid flowing through the flow path inside the measuring tube 100 are calculated.

The control unit 300 may include a housing 310 and a controller 320 . The controller 320 may be provided inside the housing 310, and the controller 320 may be connected to the ultrasonic sensor installed in the measuring tube 100 by a cable, and by using the ultrasonic sensor installed between the two ultrasonic sensors, Transmit and receive ultrasonic signals to measure fluid velocity and flow. In addition, a connection hole 300 a through which a cable for connecting the ultrasonic sensor 200 and the controller 300 is inserted may be formed on one side of the housing 310 .

The connecting pipe 400 may be provided between the measuring tube 100 and the control part 300, and by a plurality of fasteners 100b formed on one side of the measuring tube 100 and a plurality of fasteners 300b formed on one side of the control part 300 Twist and securely coupled.

The connecting pipe 400 connects the connecting hole 100a formed on one side of the measuring tube 100 and the connecting hole 300a formed on one side of the casing 310, so that the cables connecting the ultrasonic sensor and the controller are located inside the casing And protected from external contact, the connecting pipe 400 is fixedly connected to the measuring pipe 100 .

As shown in FIG. 1 c , instead of using the connecting pipe 400 shown in FIG. 1 b , it is also possible to directly connect the connecting hole 100 a of the measuring tube 100 and the connecting hole 300 a of the control part 300 .

The structure of the ultrasonic flow measuring device according to this embodiment can be changed according to needs, as shown in Fig. 1d to Fig. 1f.

2a and 2b are views for explaining a connection relationship between an ultrasonic sensor and a control part.

Referring to FIGS. 2 a and 2 b , according to an embodiment, a pair of ultrasonic sensors 200 a and 200 b disposed in a measuring tube 100 and a control part 300 may be connected by a cable 10 passing through a connecting tube 400 . That is, the cable 10 may be disposed in and connected to the connection hole 100 a formed on one side of the measuring tube 100 , the connection pipe 400 , and the connection hole 300 a formed on one side of the housing 310 .

In addition, since the measuring pipe 100 and the control part 300 are connected by the connection pipe 400 and are provided to be spaced apart by the length of the connection pipe 400, heat insulation and insulation are possible.

3 is a sectional view showing the structure of an ultrasonic flow rate measuring device according to an embodiment of the present invention.

Referring to FIG. 3 , the ultrasonic flow rate measuring device according to the embodiment is a reflective type, and includes a pair of ultrasonic sensors 200a and 200b, which are respectively provided on a pair of fixed parts 120a formed on one side of the main body part 110. and 120b, and the pair of ultrasonic sensors 200a and 200b are spaced a predetermined distance L11 and L21 from the flow path through which the fluid flows. Here, the diameter of the ultrasonic sensor and the diameter of the fixing part can be designed to be the same as each other.

In this case, the ultrasonic sensors 200a and 200b may be divided into a first part that generates one end of an actual ultrasonic signal and a second part that supports the first part. The diameter of the ultrasonic sensor may represent the diameter of the first part, and the diameter of the first part may be equal to or smaller than that of the second part.

At this time, the fixing parts 120a and 120b are formed by inclining at a predetermined angle θ with respect to the central axis of the main body part, and the predetermined angle may be formed within a range of 30 degrees to 60 degrees, preferably at 45 degrees.

The ultrasonic signal generated from the first ultrasonic sensor 200a can be reflected once on the inner surface of the flow path and transmitted to the second ultrasonic sensor 200b, or the ultrasonic signal generated from the second ultrasonic sensor 200b The signal can be reflected once on the inner surface of the flow path and transmitted to the first ultrasonic sensor 200a.

According to this embodiment, since the pair of ultrasonic sensors is disposed at a predetermined distance from the flow path, the passing path of the ultrasonic signal can be increased by L11+L21.

FIG. 4 is a view showing a detailed configuration of the controller shown in FIG. 2a, and FIGS. 5a and 5b are views for explaining a signal transmission path and a signal reception path.

Referring to FIG. 4, a controller 320 according to an embodiment may include a control unit 321 and a time-to-digital converter (TDC) 322, a first noise cancellation unit 323, a second noise cancellation unit 324, a first switch 325, a second switch 326 , an interface 327 , a display unit 328 and an output unit 329 .

The control unit 321 can generate a transmission signal with a pulse number, which is transmitted by the ultrasonic sensors 200a and 200b in the forward or reverse direction relative to the fluid flow.

The control unit 321 may be provided with a digital code generated from the time-to-digital converter 322, which corresponds to the time difference between the transmitted signal and the received signal, and is measured using this time difference corresponding to the received digital code (i.e., transit time) Fluid velocity and flow rate.

The control unit 321 may measure the passage time of the forward flow or the reverse flow of the fluid, respectively. In a general method of measuring a flow rate using a transit time difference of ultrasonic waves, reliability increases as the transit time difference in the forward and reverse directions increases. Therefore, in this embodiment, the ultrasonic sensor is arranged at a predetermined distance from the flow path in the measuring tube, so as to increase the transit time difference, thereby prolonging the transit path.

The time-to-digital converter 322 is a device that converts time information into digital codes, and can generate digital codes corresponding to the time difference (ie, transit time) between two input signals (ie, the transmitted signal and the received signal). Here, the input signal can be in the form of a pulse, or a simple rising signal from different signal sources.

Such time-to-digital converters are used, for example, in analog-to-digital converters (ADCs), phase-locked loops (PLLs), delay-locked loops (DLLs), image sensors, shape scanning devices, distance measuring devices, and the like.

The time-to-digital converter 322 is usually directly connected for impedance matching with the ultrasonic sensor. However, when receiving the final signal, since high-frequency signals have relatively low signal levels and are very sensitive to interference, a low-noise amplifier is used to increase the overall sensitivity of the receiver and reduce noise.

The first noise canceling unit 323 is connected to the signal receiving path P12 between the time-to-digital converter 322 and the first ultrasonic sensor, and can eliminate the noise of the signal received by the first ultrasonic sensor 200a. That is, the first noise canceling unit 323 can cancel out-of-band signals received by the first ultrasonic sensor 200a.

The second noise canceling unit 324 is connected to the signal receiving path P22 between the time-to-digital converter 322 and the second ultrasonic sensor, and can eliminate the noise of the signal received by the second ultrasonic sensor 200b. That is, the second noise canceling unit 324 can cancel out-of-band signals received by the second ultrasonic sensor 200b.

Here, the first noise canceling unit 323 and the second noise canceling unit 324 are described as an example, but the present invention is not limited thereto, and various components are applicable.

The first switch 325 can be connected to the signal receiving path P12 between the first noise canceling unit 323 and the first ultrasonic sensor 200a to be turned on or off. When a signal is transmitted through the first ultrasonic sensor 200a, the first switch 324 can be closed, thereby preventing the signal transmitted from the signal transmission path P11 from entering the signal reception path P12.

The second switch 326 can be connected to the signal receiving path P22 between the second noise canceling unit 324 and the second ultrasonic sensor 200b to be turned on or off. When the signal is transmitted through the second ultrasonic sensor 200b, the second switch 326 can be closed, thereby preventing the signal transmitted from the signal transmission path P21 from entering the second signal receiving path P22.

In this case, the first switch 325 and the second switch 326 may be, for example, T/R (transmit/receive) switches.

When high-voltage noise in the form of a shock wave that may be generated by an external factor in the process of transmitting or receiving a signal is received together with the signal, the first switch 325 and the second switch 326 are operated so that the internal circuit can be protected and stable operation can be performed. Measurement.

The interface 327 can transmit or receive data by interacting with an external terminal. Here, the interface 327 may be, for example, a Universal Asynchronous Receiver Transmitter (UART) that converts parallel data into serial data and transmits, but is not limited thereto, and various methods may be applied.

The display unit 328 can display the calculated flow velocity, instantaneous flow and integrated flow on the screen.

The output unit 329 can output the calculated flow rate, the instantaneous flow rate and the integral flow rate in an analog way. For example, the output unit 329 may convert the calculated flow into a magnitude of current or voltage to output the converted flow.

The output unit 329 may include a digital-to-analog converter (DAC) 329a and an analog output unit 329b. The digital-to-analog converter 329a can convert the digital signal into an analog signal and output it to the analog output unit 329b.

Referring to FIG. 5 a , the signal transmission path P11 according to the embodiment may include a control unit 321 , a time-to-digital converter 322 and a first ultrasonic sensor 200 a. The pulsed transmit signal generated by the control unit 321 can be provided to the first ultrasonic sensor 200 a through the time-to-digital converter 322 .

The signal receiving path P22 according to the embodiment may include the second ultrasonic sensor 200 b , the second switch 326 , the second noise canceling unit 324 , the time-to-digital converter 322 and the control unit 321 . The signal received by the second ultrasonic sensor 200 b can be provided to the control unit 321 through the second switch 326 , the second noise canceling unit 324 and the time-to-digital converter 322 in sequence.

Referring to FIG. 5 b , the signal transmission path P21 according to the embodiment may include a control unit 321 , a time-to-digital converter 322 and a second ultrasonic sensor 200 b. The pulsed transmission signal generated by the control unit 321 can be provided to the second ultrasonic sensor 200b through the time-to-digital converter 322 .

The signal receiving path P12 according to the embodiment may include the first ultrasonic sensor 200 a , the first switch 325 , the first noise canceling unit 323 , the time-to-digital converter 322 and the control unit 321 . The signal received by the first ultrasonic sensor 200 a can be provided to the control unit 321 through the first switch 325 , the first noise canceling unit 323 and the time-to-digital converter 322 in sequence.

FIG. 6 is a view showing an ultrasonic flow rate measuring method according to a first embodiment of the present invention.

Referring to FIG. 6, an ultrasonic flow measuring device (hereinafter referred to as a measuring device) according to an embodiment emits an ultrasonic signal in a forward direction relative to the flow of fluid (S610), and can measure the ultrasonic signal emitted in the forward direction. The forward transit time of the sound wave signal (t _downstream ). The forward pass time may be obtained from a time-to-digital converter (S620).

其中c為該流體的聲速，v為該流體流動的平均速度，L為該兩個超音波感測器之間的該超音波訊號的該通過距離，而θ是該超音波感測器的傾角。這裡，參考圖3，L是L11、L12、L21及L22的總和。 The forward transit time can be defined in Equation 1 below. [Formula 1]

Wherein c is the speed of sound of the fluid, v is the average velocity of the fluid flow, L is the passing distance of the ultrasonic signal between the two ultrasonic sensors, and θ is the inclination angle of the ultrasonic sensor . Here, referring to FIG. 3 , L is the sum of L11, L12, L21, and L22.

Next, the measuring device emits an ultrasonic signal in a reverse direction relative to the fluid flow (S630), and may measure a reverse transit time (t _upstream ) of the ultrasonic signal emitted in the reverse direction. The reverse transit time may be obtained from a time-to-digital converter (S640).

The reverse transit time can be defined in [Equation 2] below. [Formula 2]

、

The above [Equation 1] and [Equation 2] are summarized in the following [Equation 3]. [Formula 3]

,

[方程式5]

Next, the measurement device may calculate the flow rate using the transit times (t _upstream and t _downstream ) ( S650 ). The flow velocity v and the sound velocity c are obtained from the two equations in [Equation 3], respectively, and are defined in [Equation 4] and [Equation 5] below. [Formula 4]

[Formula 5]

Next, the measuring device may calculate a volume flow rate using the calculated flow velocity (v) (S660).

、

At this time, since the area affected by the flow in the measuring tube is within the range of the passing distance of the ultrasonic signal, L'=L12+L22, the forward passing time and reverse passing time can be calculated as the passing distance L' and the passing distance L and is defined in Equation 6 below. [Formula 6]

,

、

If the above [Equation 6] is defined as the passage time, it can be expressed as the following [Equation 7]. [Formula 7]

,

If [Equation 7] is applied to [Equation 4], the element (t _upstream -t _downstream ) in [Equation 4] (i.e. the difference Δt between the two transit times) is calculated using the area through which the fluid does not flow, L11 and L21 to calculate. However, when the reverse time is subtracted from the forward time of the total passing distance L (=L11+L12+L21+L22), the same value as the calculation result of the time difference of only (L12+L22) is obtained by compensation. Therefore, if applied without multiplying by the ratio of passing distance shown in [Equation 7], it is defined as [Equation 8] below. [Formula 8]

If using [Equation 8], the volumetric flow rate (i.e. flow q _v ) is defined as follows [Equation 9] [Equation 9]

Here, A represents the cross-sectional area of the flow path through which the fluid flows in the measuring tube.

FIG. 7 is a view showing an ultrasonic flow rate measurement method according to a second embodiment of the present invention.

Referring to FIG. 7, an ultrasonic flow measuring device (hereinafter referred to as a measuring device) according to an embodiment emits an ultrasonic signal in a forward direction relative to the flow of fluid (S710), and can measure the ultrasonic signal emitted in the forward direction. The forward transit time of the sound wave signal (t _downstream ). The forward transit time (t _downstream ) can be obtained from the time-to-digital converter (S720).

At this time, the measurement device may calculate the average value of the obtained forward transit time t _downstream and the forward transit time calculated by Equation 1, and correct the calculated average value by the forward transit time t _downstream ( S721 ).

Next, the measuring device emits an ultrasonic signal in a reverse direction relative to the fluid flow (S730), and may measure a reverse transit time (t _upstream ) of the ultrasonic signal emitted in the reverse direction. The reverse transit time may be obtained from a time-to-digital converter (S740).

At this time, the measuring device may calculate the average value of the acquired reverse transit time t _upstream and the reverse transit time calculated by Equation 2, and correct the calculated average value by the reverse transit time t _upstream ( S741 ).

Next, the measurement device may use the passing times (t _upstream and t _downstream ) to calculate the flow rate ( S750 ).

Next, the measuring device may calculate a volume flow rate using the calculated flow rate (S760).

The term "unit" used in this embodiment refers to a software or hardware component such as a Field Programmable Gate Array (FPGA) or ASIC, and a "unit" performs some of these roles. However, a "unit" is not limited to software or hardware. A "unit" may be configured to be stored in an addressable storage medium or may be constructed to execute on one or more processors. Thus, by way of example, a "unit" includes components such as software components, object-oriented software components, class and task components, programs, functions, properties and procedures, subroutines, program code segments, drivers, firmware, microcode, Circuits, data, databases, data structures, tables, arrays, and variables. The functionality provided by components and "units" may be combined with a smaller number of components and "units" or further separated into additional components and "units". Furthermore, components and "units" may be implemented to execute one or more CPUs in a device or a secure multimedia card.

The above has been described with reference to the preferred embodiments of the present invention, but it should be understood that those skilled in the art can make various modifications and changes to the present invention within the scope of not departing from the spirit and scope of the present invention, as proposed in the following claims .

10: Cable 100: Measuring tube 100a: connecting hole 100b: Fasteners 110: Main body 120: fixed part 120a: fixed part 120b: fixed part 130: coupling part 140: cover 200: Ultrasonic sensor 200a: Ultrasonic sensor 200b: Ultrasonic sensor 300: control department 300a: connecting hole 300b: Fasteners 310: shell 320: controller 321: control unit 322: Time to digital converter 323: The first noise elimination unit 324: The second noise cancellation unit 325: first switch 326: second switch 327: interface 328: display unit 329: output unit 329a: Digital to Analog Converter 329b: Analog output unit 400: connecting pipe L11: predetermined distance L12: Distance L21: predetermined distance L22: Distance P11: Signal transmission path P12: Signal receiving path P21: Signal transmission path P22: Signal receiving path θ: inclination

[ FIGS. 1 a to 1 f ] are views showing an ultrasonic flow rate measuring device according to an embodiment of the present invention.

[FIGS. 2a and 2b] are views for explaining the connection relationship between the ultrasonic sensor and the control section.

[ Fig. 3 ] is a cross-sectional view showing the structure of an ultrasonic flow rate measuring device according to an embodiment of the present invention.

[ Fig. 4 ] is a view showing a detailed configuration of the controller shown in Fig. 2a.

[FIGS. 5a and 5b] are views for explaining a signal transmission path and a signal reception path.

[ Fig. 6 ] is a view showing an ultrasonic flow rate measuring method according to a first embodiment of the present invention.

[ Fig. 7 ] is a view showing an ultrasonic flow rate measuring method according to a second embodiment of the present invention.

200a: Ultrasonic sensor

200b: Ultrasonic sensor

320: controller

321: control unit

322: Time to digital converter

323: The first noise elimination unit

324: The second noise cancellation unit

325: first switch

326: second switch

327: interface

328: display unit

329: output unit

329a: Digital to Analog Converter

329b: Analog output unit

P11: Signal transmission path

P12: Signal receiving path

P21: Signal transmission path

P22: Signal receiving path

Claims (2)

A controller for an ultrasonic flow measuring device, wherein a pair of ultrasonic sensors is arranged on at least one side of a measuring tube through which fluid flows, and the controller includes: a plurality of switches respectively connected to the pair of ultrasonic sensors A device to open or close the signal receiving path for transmitting and receiving signals; a plurality of noise canceling units to eliminate the noise of the received signal transmitted to the signal receiving path; a time-to-digital converter to output a digital code, the digital code corresponding to the time difference between the time of reception of the received signal and the time of transmission of the transmitted signal from which the noise is eliminated; and a control unit receiving during forward signal transmission and reverse signal transmission relative to the direction of movement of the fluid respectively output a plurality of digital codes, and use the received plurality of digital codes to calculate the flow rate and flow rate of the fluid, wherein the control unit uses the passage time corresponding to the digital code and the passage time calculated by the equation The average value is used to correct the transit time corresponding to the digital code, during the forward signal transmission, the transit time calculated by the equation is given by the equation

obtained, and in the process of the reverse signal transmission, the transit time calculated by the equation is given by the equation

Obtain, c is the speed of sound of the fluid, v is the average velocity of the fluid, L is the passing distance of the ultrasonic signal between the two ultrasonic sensors, and θ is the inclination angle of the ultrasonic sensor . An ultrasonic flow measurement method of an ultrasonic flow measurement device, the ultrasonic flow measurement device includes a time-to-digital converter to measure the passing time between a pair of ultrasonic sensors arranged in a fluid at least one side of the measuring tube through which the flow passes, the method comprising the steps of: measuring, by the time-to-digital converter, the forward direction of the ultrasonic signal by emitting the ultrasonic signal in a forward direction relative to the direction of movement of the fluid transit time; by transmitting the ultrasonic signal in the reverse direction, measuring the reverse transit time of the ultrasonic signal by the time-to-digital converter; and using the measured forward transit time and reverse transit time to calculating the flow rate and flow rate of the fluid, wherein, in the step of measuring the forward transit time, the forward transit time measured by the time-to-digital converter is determined by the forward transit time measured by the time-to-digital converter Corrected for the average of the forward transit time and the transit time calculated by Equation 1, which is calculated by Equation 1 during forward signal transmission

Obtained, in the step of measuring the reverse passage time, the reverse passage time measured by the time-to-digital converter is calculated by the reverse passage time measured by the time-to-digital converter and by Equation 2 Corrected by the average value of the transit time calculated by Equation 2 during the reverse signal transmission by Equation 2

Obtain, c is the speed of sound of the fluid, v is the average velocity of the fluid, L is the passing distance of the ultrasonic signal between the two ultrasonic sensors, and θ is the inclination angle of the ultrasonic sensor .

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