Ultrasonic flow rate meter and method for detecting flow rate detection
The ultrasonic flowmeter addresses signal attenuation and detection issues in non-uniform pipes by adjusting diameter parameters and ensuring signal stability, enabling accurate flow rate measurement and reducing energy consumption.
Patent Information
- Application Number
- JP2024063566
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-04-10
- Publication Date
- 2025-10-23
- Estimated Expiration
- 2044-04-10
AI Technical Summary
Ultrasonic flow meters face challenges in accurately measuring fluid flow rates due to signal attenuation and detection issues caused by non-uniform pipe wall thickness and fittings, leading to undetectable time differences or excessive signal loss.
The ultrasonic flowmeter employs a first and second sensor with a processing circuit to emit and receive ultrasonic signals, adjusting the inner and outer diameter parameters to ensure signal stability, and increasing signal transmission if stability thresholds are not met, allowing for accurate flow rate calculation.
This approach ensures reliable fluid flow rate measurement by enhancing signal stability and preventing energy wastage due to excessive emissions, thus overcoming the limitations of non-uniform pipe thickness and fittings.
Smart Images
Figure 2025160784000001_ABST
Abstract
Description
[Technical Field]
[0001] TECHNICAL FIELD The present disclosure relates to fluid flow detection, and more particularly to ultrasonic flow meters and methods of flow detection. [Background technology]
[0002] Flow meters are one of the important instruments in industrial measurement, and are closely related to various industrial applications and scientific research, and the requirements for measurement accuracy are becoming increasingly higher. Flow meters are widely used in various fields, for example, in the semiconductor manufacturing process, where they are used in the manufacturing processes of coating equipment, etching equipment, cleaning equipment, and drying equipment.
[0003] Ultrasonic flowmeters have evolved and are now used in many industries. Although ultrasonic flowmeters are relatively new measuring instruments, they are non-contact with the object being measured, so they do not create resistance in the fluid, have a long sensor life, and do not pollute. As a result, they have attracted attention and are being used in a wider range of industries in recent years.
[0004] An ultrasonic flow meter typically includes a transmitter that emits an ultrasonic signal and a receiver that receives the ultrasonic signal. The transmitter and receiver are disposed at two positions in a fluid transport line, respectively, to emit and receive ultrasonic signals, and detect the flow rate of the fluid in the fluid transport line based on the time difference between the emission and reception. However, if either the transmitter or receiver of the ultrasonic flow meter is disposed in a sleeve or a bend in the fluid transport line (i.e., a portion where the pipe wall is too thick), the ultrasonic signal emitted by the transmitter may be affected (causing an undetectable time difference or excessive signal attenuation) and may not reach the receiver. Therefore, existing ultrasonic flow meters cannot be dynamically applied to measure the flow rate of a fluid transported through a fluid transport line of any thickness. Summary of the Invention [Problem to be solved by the invention]
[0005] The main object of the present disclosure is to provide an ultrasonic flowmeter and a flow rate detection method that prevent the occurrence of a situation in which an ultrasonic signal cannot be detected based on the inner diameter and outer diameter values of a pipe set according to specifications due to differences caused by deposits in the inner diameter of the pipe or differences in the thickness of the outer diameter due to a sleeve or relay pipe on the outer diameter (the time difference between the transmission time and the standard time cannot be detected, or the signal is excessively attenuated). [Means for solving the problem]
[0006] In order to achieve the above object, an ultrasonic flow meter according to the present disclosure includes a first sensor and a second sensor disposed in a pipe having a non-uniform wall thickness and configured to emit and receive signals, and a processing circuit coupled to the first sensor and the second sensor, wherein the processing circuit includes steps (a) of controlling the first sensor and the second sensor to emit a first emitted ultrasonic signal and a second emitted ultrasonic signal, respectively, in an emission time cycle, (b) of controlling the second sensor to receive the first emitted ultrasonic signal and (c) of controlling the first sensor to receive the second emitted ultrasonic signal, and (c) of determining a first signal stability of the first emitted ultrasonic signal received by the second sensor and a second signal stability of the second emitted ultrasonic signal received by the first sensor. and a second signal stability of the first transmitted ultrasonic signal is greater than a stability threshold; if the first signal stability or the second signal stability is not greater than the stability threshold, a step (d) of increasing the number of times each of the first transmitted ultrasonic signal and the second transmitted ultrasonic signal is transmitted, adjusting the inner diameter parameter and the outer diameter parameter of the pipe, and returning to the step (a); and if the first signal stability and the second signal stability are greater than the stability threshold, a step (e) of calculating a flow rate of fluid based on the time of transmission of the first transmitted ultrasonic signal, the time of reception of the first transmitted ultrasonic signal, the time of transmission of the second transmitted ultrasonic signal, and the time of reception of the second transmitted ultrasonic signal.
[0007] In order to achieve the above object, a flow rate detection method according to the present disclosure is a flow rate detection method applied to an ultrasonic flow meter disposed in a pipe having a non-uniform wall thickness and including a first sensor, a second sensor, and a processing circuit, the method comprising the steps of: (a) controlling the first sensor and the second sensor by the processing circuit to emit a first emitted ultrasonic signal and a second emitted ultrasonic signal, respectively, in an emission time cycle; (b) controlling the second sensor by the processing circuit to receive the first emitted ultrasonic signal and the first sensor to receive the second emitted ultrasonic signal; and (c) measuring, by the processing circuit, a first signal stability of the first emitted ultrasonic signal received by the second sensor and a second signal stability of the second emitted ultrasonic signal received by the first sensor. and (c) detecting whether the first signal stability and the second signal stability are greater than a stability threshold; and (d) increasing the number of times each of the first emitted ultrasonic signal and the second emitted ultrasonic signal is emitted by the processing circuit when the first signal stability or the second signal stability is not greater than the stability threshold, adjusting the inner diameter parameter and the outer diameter parameter of the pipe, and returning to (a). And (e) calculating, by the processing circuit when the first signal stability and the second signal stability are greater than the stability threshold, a flow rate of fluid based on the time when the first emitted ultrasonic signal was emitted, the time when the first emitted ultrasonic signal was received, the time when the second emitted ultrasonic signal was emitted, and the time when the second emitted ultrasonic signal was received. [Effects of the Invention]
[0008] Compared with related art, the present disclosure determines whether the transmission stability of the ultrasonic signal is too low, thereby increasing the number of times the ultrasonic signal is emitted within a certain emission time, thereby preventing the ultrasonic signal from being transmitted incorrectly due to the pipe wall or the pipe wall of the pipe joint, making it impossible to measure the flow rate of the fluid in the pipe. [Brief explanation of the drawings]
[0009] [Figure 1A] 1 is a schematic cross-sectional view of an ultrasonic flow meter according to some embodiments. FIG. [Figure 1B]FIG. 1 is a block diagram of an ultrasonic flow meter according to some embodiments. [Figure 2A] 3A and 3B are schematic diagrams illustrating the placement of a first sensor and a second sensor in some embodiments. [Figure 2B] 3A and 3B are schematic diagrams illustrating the placement of a first sensor and a second sensor in some embodiments. [Figure 3] FIG. 1 is a schematic diagram showing the waveform of an ultrasonic signal in a general case. [Figure 4] 1 is a flowchart of a flow detection method according to some embodiments. [Figure 5] 1A-1C are schematic diagrams illustrating a comparison of ultrasound signal waveforms in some embodiments. [Figure 6] FIG. 10 is a detailed schematic diagram of a waveform of a received first emitted ultrasonic signal in some embodiments. [Figure 7] 4A-4C are schematic diagrams of waveforms of ultrasound signals in some other embodiments. [Figure 8] FIG. 10 is a detailed schematic diagram of a waveform of a received ultrasound signal in some other embodiments. [Figure 9] 10 is a flowchart illustrating further steps included in a flow detection method in some embodiments. [Figure 10] FIG. 2 is a schematic diagram illustrating a distance-amplitude characteristic curve of a received ultrasound signal in some embodiments. [Figure 11] 10 is a flowchart of steps further included in one step of a flow rate detection method in some embodiments. DETAILED DESCRIPTION OF THE INVENTION
[0010] 1A and 1B, Fig. 1A is a schematic longitudinal cross-sectional view of an ultrasonic flow meter 100 according to some embodiments, and Fig. 1B is a block diagram of the ultrasonic flow meter 100 according to some embodiments. As shown in Fig. 1A and 1B, the ultrasonic flow meter 100 of the present disclosure includes a first sensor (transducer) 110(a), a second sensor 110(b), and a processing circuit 120, and the processing circuit 120 is coupled to the first sensor 110(a) and the second sensor 110(b).
[0011] In some embodiments, the first sensor 110(a) and the second sensor 110(b) may be implemented by any ultrasonic sensor element or circuitry. In some embodiments, the processing circuitry 120 may be implemented by, but is not limited to, a central processing unit (CPU), a microcontroller (MCU), a programmable logic controller (PLC), a system-on-chip (SoC), or a field programmable gate array (FPGA).
[0012] In some embodiments, the ultrasonic flowmeter 100 may further include an input interface (not shown) and a memory (not shown). In some embodiments, a user can input the fluid type, the average outer diameter of the pipe PP and the pipe fitting PF, the inner diameter r1 of the pipe, the wall thickness of the pipe PP (i.e., the outer diameter r2 of the pipe minus the inner diameter r1), the material and installation method of the pipe PP through the input interface. In some embodiments, the processing circuit 120 reads the sound speed of the corresponding fluid type and the sound speed of the corresponding pipe PP material from the memory based on the above input data, and calculates the horizontal installation distance between the first sensor 110(a) and the second sensor 110(b), the launch time cycle (also referred to as a prewave time period), and the ultrasonic propagation time based on the above input data, the sound speed of the corresponding fluid type, and the sound speed of the corresponding pipe PP material. Next, the processing circuit 120 calculates a receiver window time cycle for the ultrasonic signal based on the emission time cycle and the ultrasonic propagation time, and can detect a time difference (to be described later) between the receiver window time cycles. Here, the receiver window time cycle is a time cycle during which the ultrasonic signal can be received. Note that the above calculation methods are commonly used in the art, and therefore will not be described in detail here.
[0013] In this embodiment, the first sensor 110(a) and the second sensor 110(b) are arranged in pairs so as to be positioned on the same straight line on the outer surface S1 of the pipe PP of the flow path and the outer surface S2 of the pipe fitting PF (i.e., the V method commonly used in the art). However, the pair arrangement of the first sensor 110(a) and the second sensor 110(b) is not limited to that shown in FIG. 1A; in other embodiments, the first sensor 110(a) and the second sensor 110(b) may be arranged in other arrangement methods (e.g., the Z method, the N method, or the W method commonly used in the art). Since the pipe fitting PF is fitted to the pipe PP (i.e., it can be considered a pipe with a non-uniform wall thickness), the outer diameter r2 of the pipe PP where the first sensor 110(a) is disposed and the outer diameter r3 of the pipe fitting PF where the second sensor 110(b) is disposed will not be the same, and the reasonable range of pipe outer diameters in this case will be the range between the outer diameter r2 of the pipe PP where the first sensor 110(a) is disposed and the outer diameter r3 of the pipe fitting PF where the second sensor 110(b) is disposed. For example, the average value of the outer diameters r2 and r3 may be used as the average outer diameter, and the above-mentioned calculation may be performed using this average outer diameter, but this is not limited to this.
[0014] Here, an example has been given in which the pipe joint PF is a sleeve joint, but in other embodiments, the ultrasonic flowmeter 100 can also be applied to cases in which the pipe joint PF is an elbow joint.
[0015] The following describes, using examples, the arrangement of the first sensor 110(a) and the second sensor 110(b) and different types of pipe fittings PF. Also referring to FIG. 2A, FIG. 2A shows the arrangement of the first sensor 110(a) and the second sensor 110(b) in some embodiments. As shown in FIG. 2A, the difference from FIG. 1A is that the pipe fitting PF is an elbow fitting, and the first sensor 110(a) and the second sensor 110(b) are arranged at both ends of a bent portion on the outer surface S2 of the pipe fitting PF. Another difference between FIG. 2A and FIG. 1A is that the first sensor 110(a) directly transmits a first emitted ultrasonic signal us to the second sensor 110(b), and the second sensor 110(a) directly transmits a second emitted ultrasonic signal ds to the first sensor 110(b). Here, the first emitted ultrasonic signal us and the second emitted ultrasonic signal ds do not generate reflections in the pipe PP as in Fig. 1A (i.e., a transmission method similar to the Z-method). In this embodiment, the processing circuit 120 can calculate the horizontal mounting distance between the first sensor 110(a) and the second sensor 110(b), the emission time cycle, the ultrasonic transmission time, and the receive window time cycle using the same method as described above.
[0016] Referring also to FIG. 2B, FIG. 2B illustrates the arrangement of the first sensor 110(a) and the second sensor 110(b) in some embodiments. As shown in FIG. 2B, the difference from FIG. 1A is that the first sensor 110(a) and the second sensor 110(b) are arranged in non-linear positions on the outer surface S1 of the pipe PP and the outer surface S2 of the pipe fitting PF, respectively, using the Z-law method. Another difference between FIG. 2B and FIG. 1A is that the first sensor 110(a) directly transmits a first emitted ultrasonic signal us to the second sensor 110(b), and the second sensor 110(a) directly transmits a second emitted ultrasonic signal ds to the first sensor 110(b). Here, the first emitted ultrasonic signal us and the second emitted ultrasonic signal ds do not generate reflections in the pipe PP as in FIG. 1A (i.e., the Z-law transmission method). In this embodiment, the processing circuit 120 can calculate the horizontal mounting distance between the first sensor 110(a) and the second sensor 110(b), the emission time cycle, the ultrasonic transmission time, and the receive window time cycle in a manner similar to that described above.
[0017] Furthermore, generally, a first sensor 110(a) is used to emit a first ultrasonic signal us and receive a second ultrasonic signal ds emitted by a second sensor 110(b), and the second sensor 110(b) is used to emit a second ultrasonic signal ds and receive the first ultrasonic signal us emitted by the first sensor 110(a). The first sensor 110(a) emits the first ultrasonic signal us obliquely relative to the flow direction FD of the fluid in the flow path (e.g., flow direction from left to right), which is received by the second sensor 110(b). At the same time, the second sensor 110(b) emits a second ultrasonic signal ds obliquely in the opposite direction to the flow direction of the fluid in the flow path (i.e., the direction opposite to the flow direction FD), which is received by the first sensor 110(a). In this manner, the flow rate can be measured from the difference in transmission time between the first ultrasonic signal us and the second ultrasonic signal ds in the fluid.
[0018] 1A and 3, the first sensor 110(a) and the second sensor 110(b) simultaneously emit signals at the same frequency (e.g., 3 MHz) during a transmission time cycle RT. The first ultrasonic signal us emitted by the first sensor 110(a) propagates through the pipe PP, and after a certain time, the second sensor 110(b) receives the first ultrasonic signal us emitted by the first sensor 110(a). Similarly, the ultrasonic signal ds emitted by the second sensor 110(b) also propagates through the pipe PP, and after a certain time, the first sensor 110(a) also receives the second ultrasonic signal ds emitted by the second sensor 110(b). Because the flow velocity and flow direction FD of the liquid propagate in the same direction as the propagation direction of the first emitted ultrasonic signal us emitted by the first sensor 110(a) (e.g., toward the right side of the pipe PP), the time when the second sensor 110(b) receives the first emitted ultrasonic signal us is earlier than the time when the first sensor 110(a) receives the second emitted ultrasonic signal ds. On the other hand, because the flow velocity and flow direction FD of the liquid propagate in the same direction as the propagation direction of the second emitted ultrasonic signal ds emitted by the second sensor 110(b), the time when the first sensor 110(a) receives the second emitted ultrasonic signal ds is later than the time when the second sensor 110(b) receives the first emitted ultrasonic signal us.
[0019] Based on this, the processing circuit 120 detects the time tt1 it takes for the second sensor 110(b) to receive the first emitted ultrasonic signal us and the time tt2 it takes for the first sensor 110(a) to receive the second emitted ultrasonic signal ds during the receive window time cycle WT, and calculates the time difference Δt between the times tt1 and tt2. Next, the processing circuit 120 calculates the flow velocity and flow rate of the liquid in the pipe PP (i.e., the measurement values obtained by the ultrasonic flowmeter 100 using a frequency of 3 MHz) using a time of flight (TOF) method based on the time difference Δt between the time when the first sensor 110(a) and the second sensor 110(b) received the second emitted ultrasonic signal ds and the time when the first sensor 110(a) and the second sensor 110(b) received the first emitted ultrasonic signal us, respectively. Note that the present disclosure is not limited to calculation formulas for the flow velocity and flow rate designed using the principles of the time of flight method.
[0020] However, because the second sensor 110(b) is disposed on the outer surface S2 of the pipe fitting PF, and both the first emitted ultrasonic signal us and the second emitted ultrasonic signal ds must pass through the pipe wall of the pipe PP and the pipe fitting PF, an excessively thick pipe wall may cause the second sensor 110(b) to be unable to receive the first emitted ultrasonic signal us emitted by the first sensor 110(a) or the second emitted ultrasonic signal ds emitted by the second sensor 110(b). Alternatively, the first emitted ultrasonic signal us received by the second sensor 110(b) or the second emitted ultrasonic signal ds received by the first sensor 110(a) may have poor signal stability (i.e., a low signal-to-noise ratio (SNR)). Furthermore, the pipe fitting PF is more likely to have a difference in transmission time compared to a typical arrangement (this transmission time difference will be described later). As a result, the fluid flow velocity and flow rate cannot be calculated using the time difference method. Based on this, the present disclosure provides a flow rate detection method for solving the problem that the second sensor 110(b) and the first sensor 110(a) may not be able to receive the first emitted ultrasonic signal us and the second emitted ultrasonic signal ds, respectively, or that the signal stability may be poor. Furthermore, the flow rate detection method of the present disclosure eliminates the above-mentioned transmission time difference by adjusting the inner diameter parameter and the outer diameter parameter (i.e., the transmission time difference can be corrected by appropriately adjusting the inner diameter of the pipe PP and the average outer diameter between the pipe PP and the pipe fitting PF). In some embodiments, the inner diameter parameter includes the inner diameter of the pipe PP, and the outer diameter parameter includes the average outer diameter of the pipe PP and the pipe fitting PF. Detailed steps will be described later, so a detailed description will be omitted here.
[0021] 4, which shows a flowchart of a flow rate detection method in some embodiments applicable to the ultrasonic flowmeter 100 shown in FIGS. 1A and 1B. As shown in FIG. 4, first, in step S410, the processing circuit 120 controls the first sensor 110(a) and the second sensor 110(b) to emit a first emitted ultrasonic signal us and a second emitted ultrasonic signal ds in an emission time cycle RT. In some embodiments, the processing circuit 120 can set the number of emission times of each of the first emitted ultrasonic signal us and the second emitted ultrasonic signal ds to 1 in an initial state. In other words, in the initial state, the processing circuit 120 can control the first sensor 110(a) to emit a forward-propagating first emitted ultrasonic signal us and a backward-propagating second emitted ultrasonic signal ds in an emission time cycle RT. In other embodiments, in the initial state, the processing circuit 120 can set the number of emission times of each of the first emitted ultrasonic signal us and the second emitted ultrasonic signal ds to, but is not limited to, another positive integer.
[0022] In step S420, the processing circuit 120 controls the second sensor 110(b) to receive the first emitted ultrasonic signal us and controls the first sensor 110(a) to receive the second emitted ultrasonic signal ds. In step S430, the processing circuit 120 detects whether the first signal stability of the first emitted ultrasonic signal us received by the second sensor 110(b) and the second signal stability of the second emitted ultrasonic signal ds received by the first sensor 110(a) are greater than a stability threshold. If the first signal stability of the received first emitted ultrasonic signal us or the second signal stability of the received second emitted ultrasonic signal ds is not greater than the stability threshold, the processing circuit 120 executes step S440. Conversely, if the first signal stability of the received first emitted ultrasonic signal us and the second signal stability of the received second emitted ultrasonic signal ds are greater than the stability threshold, the processing circuit 120 executes step S450.
[0023] In some embodiments, the signal-to-noise ratio threshold may be preset and stored in the memory of the ultrasonic flowmeter 100. In some embodiments, the first signal stability of the first emitted ultrasonic signal us described above is the signal-to-noise ratio of the waveform of the received first emitted ultrasonic signal us, and the stability threshold is the signal-to-noise ratio threshold. In some embodiments, the processing circuit 120 may calculate the mean value and standard deviation of noise from the received first emitted ultrasonic signal us. The processing circuit 120 may then sample multiple peak values of the received first emitted ultrasonic signal us and calculate the signal-to-noise ratio of the waveform of the received first emitted ultrasonic signal us based on the multiple peak values, the mean value of noise, and the standard deviation of noise. Similarly, the second signal stability is calculated from the second emitted ultrasonic signal ds in a similar manner, and a detailed description thereof will be omitted here.
[0024] Since the frequency of the first emitted ultrasonic signal us transmitted from the first sensor 110(a) is known (e.g., 3 MHz), the processing circuit 120 may distinguish noise from the waveform of the received first emitted ultrasonic signal us based on the frequency of the received first emitted ultrasonic signal us, and further calculate the average value and standard deviation of the noise magnitude. Here, this calculation method is also known in the art, so a detailed description thereof will be omitted here.
[0025] The comparison between the first signal stability and the stability threshold will now be described with reference to an example. Also referring to FIG. 5, FIG. 5 is a schematic diagram illustrating a comparison of waveforms of the first emitted ultrasonic signal us in some embodiments. As shown in FIG. 5, when a pipe fitting PF is present, the first sensor 110(a) emits a first emitted ultrasonic signal us of a specific frequency during an emission time cycle RT, and the second sensor 110(b) receives the first emitted ultrasonic signal us emitted by the first sensor 110(a) during a receive window time cycle WT.
[0026] Note that there is a time tt1' between transmitting the first emitted ultrasonic signal us and receiving the first emitted ultrasonic signal us. Compared to the example of FIG. 3, in which the pipe fitting PF is not present, there is a transmission time difference Δt' between time tt1' and time tt1. This transmission time difference Δt' is due to the non-uniformity of the pipe wall thickness. In step S440, which will be described later, the processing circuit 120 adjusts the inner diameter parameter and the outer diameter parameter so that the user adjusts the inner diameter of the pipe PP and the average outer diameter of the pipe PP and the pipe fitting PF (e.g., selects a pipe PP and pipe fitting PF with a thinner inner diameter or a thinner average outer diameter to eliminate the transmission time difference Δt'), and further changes the inner diameter of the pipe PP and the average outer diameter of the pipe PP and the pipe fitting PF based on the inner diameter parameter and the outer diameter parameter.
[0027] Next, the processing circuit 120 detects the signal-to-noise ratio of the first emitted ultrasonic signal us received by the second sensor 110(b). Furthermore, referring also to FIG. 6, FIG. 6 is a detailed schematic diagram of the waveform of the received first emitted ultrasonic signal us in some embodiments. As shown in FIG. 6, the processing circuit 120 distinguishes the signal received before time t1 and after time t2 from noise based on a specific frequency of the first emitted ultrasonic signal us, and calculates the mean value and standard deviation based on the waveform peak values of the noise. Then, the processing circuit 120 determines that the signal-to-noise ratio of the first emitted ultrasonic signal us is not greater than the stability threshold based on the noise mean value, noise standard deviation, and waveform peak values of the signal between time t1 and t2.
[0028] 4 , in step S440, processing circuit 120 increases the number of times each of the first emitted ultrasonic signal us and the second emitted ultrasonic signal ds is emitted to adjust the inner diameter parameter and the outer diameter parameter of the non-uniform-walled tube (i.e., adjust as described above), and then returns to step S410. In other words, if processing circuit 120 detects that the first signal stability or the second signal stability is not greater than the stability threshold, in step S410, processing circuit 120 controls first sensor 110(a) and second sensor 110(b) to emit the first emitted ultrasonic signal us one more time in the next emission time cycle RT, and increases the number of times that second sensor 110(b) emits the second emitted ultrasonic signal ds in the next emission time cycle RT. At this time, the processing circuit 120 further adjusts the inner diameter parameter and the outer diameter parameter of the non-uniform pipe wall (i.e., slightly lowers the parameter value, e.g., by 10%), and continues to execute steps S420-S430 to determine whether the first signal stability of all first emitted ultrasonic signals us received by the second sensor 110(b) and the second signal stability of all second emitted ultrasonic signals ds received by the first sensor 110(a) are greater than the stability threshold. At the same time, to eliminate the time lag caused by the non-uniform pipe wall and increase the first and second signal stability, the inner diameter of the pipe PP and the average outer diameter of the pipe PP and the pipe fitting PF are adjusted according to the inner diameter parameter and the outer diameter parameter (i.e., the values of the inner diameter and the average outer diameter are adjusted to the values of the inner diameter parameter and the outer diameter parameter). From this, it can be seen that when the processing circuit 120 detects that the first signal stability or the second signal stability is not greater than the stability threshold, it simultaneously increases the number of emissions of each of the first emitted ultrasonic signal us and the second emitted ultrasonic signal ds to adjust the inner diameter parameter and the outer diameter parameter of the tube with a non-uniform wall thickness. In the present disclosure, the processing circuit 120 continues to execute steps S410 to S440 until the first signal stability and the second signal stability are greater than the stability threshold, and executes step S450 when the first signal stability and the second signal stability are greater than the stability threshold.
[0029] Below, an example will be given of the comparison between the first signal stability and the stability threshold after the processing circuit 120 increases the number of times the first emitted ultrasonic signal us is emitted (for example, by one increase). Also referring to FIG. 7, FIG. 7 is a schematic diagram of a waveform of the first emitted ultrasonic signal us in some other embodiments. As shown in FIG. 7, the first sensor 110(a) emits two first emitted ultrasonic signals us of a specific frequency during an emission time cycle RT (at this time, the first sensor 110(a) also emits two second emitted ultrasonic signals ds of a specific frequency during the emission time cycle RT). The second sensor 110(b) receives the first emitted ultrasonic signal us emitted by the first sensor 110(a) during a receive window time cycle WT. Next, the processing circuit 120 detects the signal-to-noise ratio of the first emitted ultrasonic signal us received by the second sensor 110(b). Further, referring to FIG. 8, FIG. 8 is a detailed schematic diagram of the waveform of the received first-emitted ultrasonic signal us in some other embodiments. As shown in FIG. 8, the processing circuit 120 distinguishes the signals received before time t1 and after time t2 from the first-emitted ultrasonic signal us based on a specific frequency and calculates the mean value and standard deviation based on the waveform peak values of the noise. Then, the processing circuit 120 determines that the signal-to-noise ratio of the first-emitted ultrasonic signal us is greater than the stability threshold based on the noise mean value, noise standard deviation, and waveform peak values of the signal between time t1 and time t2. At this time, the processing circuit 120 begins executing step S450 described above. The signal-to-noise ratio of the second-emitted ultrasonic signal ds is calculated from the second-emitted ultrasonic signal ds in a similar manner. The signal-to-noise ratio of the second-emitted ultrasonic signal ds is also compared with the stability threshold in a similar manner. Therefore, detailed description thereof will be omitted here.
[0030] Based on the above description, the processing circuit 120 determines whether the first signal stability and the second signal stability are greater than the stability threshold value to identify whether the waveform peak value of the received first emitted ultrasonic signal us is too low (i.e., whether the walls of the pipe PP and the pipe joint PF block most of the energy of the first emitted ultrasonic signal us) or whether the waveform peak value of the received second emitted ultrasonic signal ds is too low (i.e., whether the walls of the pipe PP and the pipe joint PF block most of the energy of the second emitted ultrasonic signal ds), and then determines whether to increase the number of times the first emitted ultrasonic signal us and the number of times the second emitted ultrasonic signal ds are emitted (i.e., whether to further increase the emission energy of the first emitted ultrasonic signal us and the second emitted ultrasonic signal ds).
[0031] In some embodiments, the processing circuit 120 may determine whether the number of emissions after the increase of the first emitted ultrasonic signal us is greater than a threshold number. If the number of emissions after the increase of the first emitted ultrasonic signal us is not greater than a preset threshold number, the processing circuit 120 may continue to execute step S410. Conversely, if the number of emissions after the increase of the first emitted ultrasonic signal us is greater than the threshold number, the processing circuit 120 may generate a warning message. In some embodiments, the warning message indicates that the type of the currently positioned first sensor 110(a) and second sensor 110(b) or the arrangement or location of the first sensor 110(a) and second sensor 110(b) is incapable of detecting the first transmission time of ultrasonic waves in the fluid. Note that the flow rate detection method of the present disclosure also determines whether to generate a warning message in a similar manner based on the number of emissions after the increase of the second emitted ultrasonic signal ds.
[0032] Based on the above description, the processing circuit 120 determines whether the number of shots after the increase of the first emitted ultrasonic signal us or the number of shots after the increase of the second emitted ultrasonic signal ds is greater than a number threshold, thereby preventing excessive energy consumption of the ultrasonic flowmeter 100 due to an excessive number of shots. In one embodiment, the number threshold is related to, but not limited to, the type of the ultrasonic flowmeter 100.
[0033] Returning to FIG. 4, in step S450, the processing circuit 120 calculates the fluid flow rate (i.e., the flow rate of the fluid in the pipe PP) based on the time when the first emitted ultrasonic signal us was emitted, the time when the first emitted ultrasonic signal us was received, the time when the second emitted ultrasonic signal ds was emitted, and the time when the second emitted ultrasonic signal ds was received.
[0034] 9, which is a flowchart illustrating steps S460 to S470 that are further included in the flow rate detection method according to some embodiments. As shown in FIG. 9, first, if the first signal stability is greater than the stability threshold, the processing circuit 120 may further execute step S460. In step S460, the processing circuit 120 detects a value of a distance amplitude curve (DAC) of the first emitted ultrasonic signal us received by the second sensor 110(b). In step S470, the processing circuit 120 adjusts the number of emissions of the first emitted ultrasonic signal us based on the value of the distance amplitude curve of the first emitted ultrasonic signal us, the lower limit value, and the number of emissions of the first emitted ultrasonic signal us, and then returns to step S410.
[0035] In some embodiments, the processing circuit 120 may detect whether all values of the distance amplitude characteristic curve of the first emitted ultrasonic signal us received by the second sensor 110(b) are greater than a preset lower limit. If at least one of the values of the distance amplitude characteristic curve of the received first emitted ultrasonic signal us is not greater than the lower limit, the processing circuit 120 may continue to execute step S410. If all values of the distance amplitude characteristic curve of the received first emitted ultrasonic signal us are greater than the lower limit, the processing circuit 120 may determine whether the number of emissions of the first emitted ultrasonic signal us is greater than one. In some embodiments, if the processing circuit 120 determines that the number of emissions of the first emitted ultrasonic signal us is not greater than one, the processing circuit 120 may continue to execute step S410. If the processing circuit 120 determines that the number of emissions of the first emitted ultrasonic signal us is greater than one, the processing circuit 120 may decrease the number of emissions of the first emitted ultrasonic signal us (e.g., by one) and continue to execute step S410 according to the decreased number of emissions of the first emitted ultrasonic signal us. In addition, the flow rate detection method of the present disclosure can also adjust the number of times the second emitted ultrasonic signal ds is emitted based on the distance-amplitude characteristic curve of the second emitted ultrasonic signal ds in a similar manner, so detailed explanation will be omitted here.
[0036] Based on the above description, the processing circuit 120 determines whether the value of the amplitude-distance curve is greater than the lower limit value, thereby avoiding the problem of the value of the amplitude-distance curve becoming excessively large due to excessive firings, and reducing the energy consumption of the ultrasonic flowmeter 100.
[0037] The comparison of the distance amplitude characteristic curve value with the lower limit will now be described with reference to an example. Also referring to FIG. 10, FIG. 10 is a schematic diagram illustrating a distance amplitude characteristic curve of a received first-emitted ultrasonic signal us in some embodiments. Assuming that the distance amplitude characteristic curve of the first-emitted ultrasonic signal us received by the second sensor 110(b) is curve DAC1, the processing circuit 120 determines that all values on the curve DAC1 are greater than the lower limit LL and then determines whether the number of emissions of the first-emitted ultrasonic signal us from the first sensor 110(a) is greater than 1. Assuming that the distance amplitude characteristic curve of the first-emitted ultrasonic signal us received by the second sensor 110(b) is curve DAC2, the processing circuit 120 determines that not all values on the curve DAC2 are greater than the lower limit LL (i.e., some values on the curve DAC2 are not greater than the lower limit LL), and directly continues to execute step S410.
[0038] 11, which is a flowchart of steps S451 to S453 that are further included in step S450 in a flow rate detection method in some embodiments. The steps included in step S450 in this flow rate detection method are also applied to the ultrasonic flowmeter 100 shown in FIGS. 1A and 1B. As shown in FIG. 11, first, in step S451, the processing circuit 120 measures a first transmission time (i.e., forward propagation time) of the ultrasonic wave in the fluid based on the time when the first emitted ultrasonic signal us is emitted and the time when the first emitted ultrasonic signal us is received.
[0039] In step S452, processing circuitry 120 measures a second transmission time (i.e., backward propagation time) of the ultrasound in the fluid based on the time at which the second transmitted ultrasonic signal ds is emitted and the time at which the second transmitted ultrasonic signal ds is received. In step S453, processing circuitry 120 calculates the flow rate of the fluid based on the first transmission time and the second transmission time. In some embodiments, processing circuitry 120 may calculate the time difference between the first transmission time and the second transmission time and calculate the flow velocity and flow rate of the fluid based on this time difference using the time difference method described above.
[0040] 3, the processing circuit 120 calculates the difference (i.e., time tt1) between the time when the first sensor 110(a) emits the first waveform peak value of the first emitted ultrasonic signal us and the time when the second sensor 110(b) receives the first waveform peak value of the first emitted ultrasonic signal us. Next, the processing circuit 120 calculates the difference (i.e., time tt2) between the time when the second sensor 110(b) emits the first waveform peak value of the second emitted ultrasonic signal ds and the time when the first sensor 110(a) receives the first waveform peak value of the second emitted ultrasonic signal ds. Next, the processing circuit 120 calculates the flow rate of the fluid based on the time difference between time tt1 and time tt2.
[0041] As described above, the ultrasonic flowmeter and flow rate detection method according to the present disclosure determine whether to increase the number of times an ultrasonic signal is emitted within a certain emission period based on the stability of the received emitted ultrasonic signal, and measure the time it takes for the emitted ultrasonic signal to propagate forward and backward through the fluid. This prevents the problem of the pipe wall or pipe joint wall blocking most of the energy of the emitted ultrasonic signal, making it impossible to effectively measure the flow rate of the fluid. Furthermore, the ultrasonic flowmeter and flow rate detection method according to the present disclosure can avoid excessive energy consumption due to excessive emission by determining whether the number of times the ultrasonic signal is emitted is greater than a threshold value. Meanwhile, the ultrasonic flowmeter and flow rate detection method according to the present disclosure can avoid the problem of the amplitude-distance curve becoming excessively large due to excessive emission by determining whether the value of the amplitude-distance curve is greater than a lower limit.
[0042] Although the preferred embodiments of the present disclosure have been described in detail above, they are not intended to limit the scope of the claims of the present disclosure, and all modifications that fall within the spirit and scope of the claims of the present disclosure and are similar thereto should be included within the scope of the present disclosure. [Explanation of symbols]
[0043] 100 Ultrasonic Flowmeter 110(a) First sensor 110(b) Second Sensor 120 Processing Circuit S1, S2 external surface us First emitted ultrasonic signal ds Second emitted ultrasonic signal PP pipe PF Pipe Fittings FD Flow direction R1 Inner diameter R2 outer diameter RT Firing Time Cycle WT Receive Window Time Cycle tt1, tt2, tt1' times Δt time difference Δt' Transmission time difference Time points t1 and t2 DAC1, DAC2 curve LL Lower limit
Claims
1. 1. An ultrasonic flow meter disposed in a pipe having a non-uniform wall thickness, The ultrasonic flow meter includes a first sensor and a second sensor configured to emit and receive signals, and a processing circuit coupled to the first sensor and the second sensor; The processing circuitry (a) controlling the first sensor and the second sensor to emit a first emitted ultrasonic signal and a second emitted ultrasonic signal, respectively, in a firing time cycle; (b) controlling the second sensor to receive the first emitted ultrasonic signal and controlling the first sensor to receive the second emitted ultrasonic signal; (c) detecting whether a first signal stability of the first emitted ultrasonic signal received by the second sensor and a second signal stability of the second emitted ultrasonic signal received by the first sensor are greater than a stability threshold; (d) if the first signal stability or the second signal stability is not greater than the stability threshold, increasing the number of times each of the first emitted ultrasonic signal and the second emitted ultrasonic signal is emitted, adjusting the inner diameter parameter and the outer diameter parameter of the tube, and returning to step (a); and (e) calculating a flow rate of a fluid based on a time at which the first emitted ultrasonic signal was emitted, a time at which the first emitted ultrasonic signal was received, a time at which the second emitted ultrasonic signal was emitted, and a time at which the second emitted ultrasonic signal was received, if the first signal stability and the second signal stability are greater than the stability threshold. Ultrasonic flow meter.
2. 2. The ultrasonic flow meter of claim 1, wherein the first signal stability of the first emitted ultrasonic signal is a signal-to-noise ratio of a waveform of the first emitted ultrasonic signal received by the second sensor, and the stability threshold is a threshold of the signal-to-noise ratio.
3. The step (d) determining whether the number of times the first emitted ultrasonic signal is emitted after the increase is greater than a number threshold; If the number of times of emission after the increase of the first emitted ultrasonic signal is not greater than the number threshold, continuously performing step (a) according to the number of times of emission after the increase of the first emitted ultrasonic signal; and generating a warning message if the number of firings after the increase in the first fired ultrasonic signal is greater than the number threshold.
4. The processing circuitry (f) detecting a value of a distance-amplitude characteristic curve of the first emitted ultrasonic signal received by the second sensor when the first signal stability is greater than the stability threshold; 2. The ultrasonic flow meter of claim 1, further configured to perform step (g) of adjusting the number of emissions of the first emitted ultrasonic signal based on the value of the distance-amplitude characteristic curve of the first emitted ultrasonic signal, a lower limit value, and the number of emissions of the first emitted ultrasonic signal.
5. The step (e) measuring a first transmission time of the ultrasonic wave in the fluid based on a time of emission of the first emitted ultrasonic signal and a time of reception of the first emitted ultrasonic signal; measuring a second transmission time of the ultrasonic wave in the fluid based on a time when the second emitted ultrasonic signal is emitted and a time when the second emitted ultrasonic signal is received; and calculating a flow rate of the fluid based on the first transit time and the second transit time.
6. 1. A method of detecting flow rate applied to an ultrasonic flow meter disposed in a pipe having a non-uniform wall thickness and including a first sensor, a second sensor, and processing circuitry, comprising: (a) controlling, by the processing circuitry, the first sensor and the second sensor to emit a first emitted ultrasonic signal and a second emitted ultrasonic signal, respectively, in a firing time cycle; (b) controlling, by the processing circuitry, the second sensor to receive the first emitted ultrasonic signal and the first sensor to receive the second emitted ultrasonic signal; (c) detecting, by the processing circuitry, whether a first signal stability of the first emitted ultrasonic signal received by the second sensor and a second signal stability of the second emitted ultrasonic signal received by the first sensor are greater than a stability threshold; (d) increasing the number of times each of the first emitted ultrasonic signal and the second emitted ultrasonic signal is emitted and adjusting the inner diameter parameter and the outer diameter parameter of the tube by the processing circuit if the first signal stability or the second signal stability is not greater than the stability threshold, and returning to step (a); and (e) if the first signal stability and the second signal stability are greater than the stability threshold, calculating, by the processing circuit, a flow rate of the fluid based on the time at which the first emitted ultrasonic signal was emitted, the time at which the first emitted ultrasonic signal was received, the time at which the second emitted ultrasonic signal was emitted, and the time at which the second emitted ultrasonic signal was received.
7. 7. The flow rate detection method of claim 6, wherein the first signal stability of the first emitted ultrasonic signal is a signal-to-noise ratio of a waveform of the first emitted ultrasonic signal received by the second sensor, and the stability threshold is a threshold of the signal-to-noise ratio.
8. The step (d) determining, by the processing circuit, whether the number of times of emission of the first emitted ultrasonic signal after the increase is greater than a number threshold; If the number of times of emission after the increase of the first emitted ultrasonic signal is not greater than the number threshold, the processing circuit continues to perform step (a) according to the number of times of emission after the increase of the first emitted ultrasonic signal; 7. The method of claim 6, further comprising generating, by the processing circuitry, a warning message if the number of emissions after the increase in the first emitted ultrasonic signal is greater than the number threshold.
9. (f) detecting, by the processing circuit, a value of a distance-amplitude characteristic curve of the first emitted ultrasonic signal received by the second sensor when the first signal stability is greater than the stability threshold; 7. The flow rate detection method of claim 6, further comprising: (g) adjusting, by the processing circuit, the number of emissions of the first emitted ultrasonic signal based on the numerical value, the lower limit value of the distance-amplitude characteristic curve of the first emitted ultrasonic signal, and the number of emissions of the first emitted ultrasonic signal.
10. The step (e) measuring, by the processing circuitry, a first transit time of the ultrasonic wave in the fluid based on a time of emission of the first emitted ultrasonic signal and a time of reception of the first emitted ultrasonic signal; measuring, by the processing circuitry, a second transit time of the ultrasonic wave in the fluid based on a time of emission of the second emitted ultrasonic signal and a time of reception of the second emitted ultrasonic signal; 7. The method of claim 6, further comprising: calculating, by the processing circuitry, a flow rate of the fluid based on the first transit time and the second transit time.