Ultrasonic flowmeter and method for attaching ultrasonic flowmeter

Abstract

To provide an ultrasonic flowmeter capable of dispensing with the adjustment of a distance in the axial direction of a pipe between one or more pairs of ultrasonic transceivers, even if the diameter of the pipe is different.SOLUTION: In an ultrasonic flowmeter 10, a pair of ultrasonic transceivers 11, 12 attached to the outer peripheral surface of the pipe 30 transmit and receive ultrasonic waves to and from each other via the fluid flowing through the pipe 30. The pair of ultrasonic transceivers 11, 12 are phased array ultrasonic transceivers 11, 12 in which a plurality of ultrasonic elements 11b and 12b adjusted to an emission angle of the ultrasonic waves with respect to the axial center of the pipe 30 at which the reception intensity of the ultrasonic waves is maximized are arranged in an array, and the pipe axial direction distance between the pair of ultrasonic transceivers 11, 12 is fixed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] TECHNICAL FIELD The present disclosure relates to ultrasonic flow meters and methods of installing ultrasonic flow meters. [Background technology]

[0002] Clamp-on ultrasonic flowmeters have been provided in the past for measuring the flow rate or flow velocity of a fluid flowing through a pipe (hereinafter referred to as "fluid measurement"). Clamp-on ultrasonic flowmeters can measure fluid flow simply by clamping to the outer surface of a pipe. This has the advantage that cutting the pipe to install the flowmeter is not necessary and it can be easily retrofitted to an existing pipe. Furthermore, because the ultrasonic flowmeter does not come into contact with the fluid, contamination of the fluid or corrosion of the flowmeter itself can be prevented. Such clamp-on ultrasonic flowmeters are disclosed, for example, in Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-158678 Summary of the Invention [Problem to be solved by the invention]

[0004] The ultrasonic flowmeter disclosed in Patent Document 1 measures fluid flow based on the difference between the propagation time of ultrasonic waves transmitted from a first ultrasonic transmitter / receiver to a second ultrasonic transmitter / receiver and the propagation time of ultrasonic waves transmitted from the second ultrasonic transmitter / receiver to the first ultrasonic transmitter / receiver. However, the ultrasonic flowmeter disclosed in Patent Document 1 requires adjustment of the distance in the axial direction of the pipe between the first ultrasonic transmitter / receiver and the second ultrasonic transmitter / receiver in order to properly transmit and receive ultrasonic waves according to the pipe diameter. Furthermore, such adjustment may become more complicated as the number of ultrasonic transmitter / receivers increases.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to provide an ultrasonic flowmeter that does not require adjustment of the axial distance of the pipe between one or more pairs of ultrasonic transmitters and receivers, even if the pipe diameters are different. [Means for solving the problem]

[0006] The ultrasonic flowmeter according to the present disclosure is an ultrasonic flowmeter in which one or more pairs of ultrasonic transmitters and receivers attached to the outer surface of a pipe transmit and receive ultrasonic waves to and from each other via a fluid flowing inside the pipe, and the one or more pairs of ultrasonic transmitters and receivers are phased array ultrasonic transmitters and receivers in which a plurality of ultrasonic elements are arranged in an array, adjusted to an ultrasonic emission angle relative to the axis of the pipe that maximizes the received strength of the ultrasonic waves, and the distance in the axial direction of the pipe between the one or more pairs of ultrasonic transmitters and receivers is fixed. [Effects of the Invention]

[0007] According to the present disclosure, even if the pipe diameters are different, it is possible to eliminate the need to adjust the distance in the pipe axial direction between one or more pairs of ultrasonic transmitters and receivers. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view showing a schematic configuration of an ultrasonic flowmeter according to a first embodiment. [Figure 2] FIG. 1 is a diagram showing how ultrasonic waves are emitted from ultrasonic elements of a phased array ultrasonic transmitter / receiver. [Figure 3] FIG. 10 is a diagram showing how the emission angle of ultrasonic waves changes when the phased array ultrasonic transmitter / receiver is fixed. [Figure 4] FIG. 1 is a diagram showing the emission of ultrasonic waves from a bulk ultrasonic transducer. [Figure 5] 10A and 10B are diagrams showing how the emission angle of ultrasonic waves in a bulk ultrasonic transducer is changed using a wedge member. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0010] Embodiment 1 An ultrasonic flowmeter 10 according to the first embodiment will be described with reference to FIGS. 1 to 5. FIG.

[0011] FIG. 1 is a cross-sectional view showing a schematic configuration of an ultrasonic flowmeter 10 according to a first embodiment. The ultrasonic flowmeter 10 according to the first embodiment is capable of measuring a fluid by transmitting and receiving ultrasonic waves through a fluid flowing inside a pipe 30. The pipe 30 is cylindrical. That is, the flow path cross section of the pipe 30 is circular. The arrows in FIG. 1 indicate the direction of fluid flow. The two-dot chain lines in FIG. 1 indicate the transmission and reception of ultrasonic waves.

[0012] 1, the ultrasonic flowmeter 10 is a so-called single-beam ultrasonic flowmeter, and includes a pair of a first phased array ultrasonic transceiver 11 and a second phased array ultrasonic transceiver 12. The first phased array ultrasonic transceiver 11 and the second phased array ultrasonic transceiver 12 transmit and receive ultrasonic waves between each other.

[0013] The ultrasonic flowmeter 10 performs fluid measurement of a fluid flowing inside a pipe 30 based on signals transmitted from the first phased array ultrasonic transceiver 11 and the second phased array ultrasonic transceiver 12. The ultrasonic flowmeter 10 performs fluid measurement based on, for example, the difference between the propagation time of ultrasonic waves transmitted from the first phased array ultrasonic transceiver 11 to the second phased array ultrasonic transceiver 12 and the propagation time of ultrasonic waves transmitted from the second phased array ultrasonic transceiver 12 to the first phased array ultrasonic transceiver 11.

[0014] Moreover, the ultrasonic flowmeter 10 is, for example, a clamp-on type ultrasonic flowmeter in which the first phased array ultrasonic transmitter / receiver 11 and the second phased array ultrasonic transmitter / receiver 12 are configured to be detachable from the outer circumferential surface of the pipe 30. The ultrasonic flowmeter 10 includes, for example, a clamp member (not shown). This clamp member generates a clamping force from the outer circumferential surface of the pipe 30 toward its radially inward direction by clamping the pipe 30 or surrounding the outer circumferential surface of the pipe 30 in its circumferential direction. Therefore, the clamp member can detachably hold the pair of phased array ultrasonic transmitter / receivers 11 and 12 to the outer circumferential surface of the pipe 30.

[0015] In this case, the first phased array ultrasonic transceiver 11 is disposed on the upstream side of the pipe 30. On the other hand, the second phased array ultrasonic transceiver 12 is disposed on the downstream side of the pipe 30. That is, the first phased array ultrasonic transceiver 11 is disposed upstream of the second phased array ultrasonic transceiver 12 in the fluid flow direction. The first phased array ultrasonic transceiver 11 and the second phased array ultrasonic transceiver 12 are disposed in opposing positions, i.e., in point-symmetric positions, with the axis of the pipe 30 as the center. Furthermore, the distance in the axial direction of the pipe 30 between the first phased array ultrasonic transceiver 11 and the second phased array ultrasonic transceiver 12 remains a fixed value even if the diameter of the pipe 30 changes.

[0016] The first phased array ultrasonic transmitter / receiver 11 is composed of, for example, one elastic couplant (first elastic couplant) 11a and a plurality of ultrasonic elements (first ultrasonic elements) 11b.

[0017] The elastic couplant 11a is elastically deformable. Therefore, when the elastic couplant 11a is pressed against the outer peripheral surface of the pipe 30, it conforms to the outer peripheral surface and adheres tightly to it. The elastic couplant 11a is made of, for example, an elastic resin material. Furthermore, ultrasonic waves can pass through the elastic couplant 11a.

[0018] The ultrasonic elements 11b are arranged in an array on the elastic couplant 11a. At this time, all of the ultrasonic elements 11b are arranged so that their tips (emitting ends) are included in one flat surface. The ultrasonic elements 11b are provided on a surface of the elastic couplant 11a that is located opposite to the surface that comes into close contact with the outer peripheral surface of the pipe 30.

[0019] Wiring 21 is connected to each ultrasonic element 11b. This wiring 21 is used to supply power to each ultrasonic element 11b and to extract signals from each ultrasonic element 11b. The multiple wirings 21 are bundled together. Therefore, for example, ultrasonic element 11b transmits (emits) ultrasonic waves by vibrating due to the supplied power. Furthermore, ultrasonic element 11b vibrates when it receives ultrasonic waves, converting the received ultrasonic waves into electric power (signals) and outputting them.

[0020] The first phased array ultrasonic transmitter / receiver 11 may be configured with MUTs (Micromachined Ultrasonic Transducers) formed using micromachining technology as the plurality of ultrasonic elements 11b arranged in an array. Examples of such MUTs include PMUTs (Piezoelectric Micromachined Ultrasonic Transducers) and CMUTs (Capacitive Micromachined Ultrasonic Transducers).

[0021] The second phased array ultrasonic transceiver 12 is composed of, for example, one elastic couplant (second elastic couplant) 12a and a plurality of ultrasonic elements (second ultrasonic elements) 12b. The second phased array ultrasonic transceiver 12 has the same configuration and function as the first phased array ultrasonic transceiver 11. Therefore, detailed description of the configuration of the second phased array ultrasonic transceiver 12 will be omitted. Wiring 22 is connected to each ultrasonic element 12b.

[0022] Here, the first phased array ultrasonic transceiver 11 and the second phased array ultrasonic transceiver 12 have a beam steering function that can steer the direction of the ultrasonic waves, i.e., the emission angle of the ultrasonic waves, by changing the phase difference between the ultrasonic waves emitted from the plurality of ultrasonic elements 11b, 12b arranged in an array. This will be explained using Figures 2 and 3. As mentioned above, in Figures 2 and 3, the first phased array ultrasonic transceiver 11 and the second phased array ultrasonic transceiver 12 have the same configuration and function, and therefore, here, the first phased array ultrasonic transceiver 11 will be explained as a representative.

[0023] Fig. 2 is a diagram showing how ultrasonic waves U1 to U3 are emitted from the ultrasonic elements 11b of the first phased array ultrasonic transmitter / receiver 11. Fig. 2 shows an example in which the first phased array ultrasonic transmitter / receiver 11 is equipped with three ultrasonic elements 11b. Fig. 3 is a diagram showing how the emission angle of the ultrasonic wave U changes when the first phased array ultrasonic transmitter / receiver 11 is fixed.

[0024] As shown in Fig. 2, the three ultrasonic elements 11b emit ultrasonic waves U1 to U3, respectively. At this time, the first phased array ultrasonic transmitter / receiver 11 shifts the phases of the ultrasonic waves U1 to U3 to form an equal phase surface S with the ultrasonic waves U1 to U3, and as a whole, the emission direction of one ultrasonic wave U can be set arbitrarily. For this reason, as shown in Fig. 3, even if the attachment position of the first phased array ultrasonic transmitter / receiver 11 with respect to the outer circumferential surface of the pipe 30 is fixed, the emission angle of the ultrasonic wave U with respect to the axis of the pipe 30 can be changed.

[0025] Therefore, in the ultrasonic flowmeter 10, even if the diameter of the pipe 30 changes, the distance in the pipe axial direction between the pair of phased array ultrasonic transmitters and receivers 11 and 12 is always fixed, and only the emission angle of the ultrasonic waves emitted by the multiple ultrasonic elements 11b and 12b with respect to the axis of the pipe 30 is adjusted so that the received intensity of the ultrasonic waves is maximized. As a result, the ultrasonic flowmeter 10 does not need to adjust the distance in the pipe axial direction between the pair of ultrasonic transmitters and receivers 11 and 12 even if the diameter of the pipe 30 changes. Therefore, the ultrasonic flowmeter 10 does not need to perform an operation of searching for an optimal position for the pair of phased array ultrasonic transmitters and receivers 11 and 12 at which ultrasonic waves can be transmitted and received reliably.

[0026] 4 and 5 are diagrams showing a conventional bulk ultrasonic transceiver 51 that does not have a beam steering function. Fig. 4 is a diagram showing how ultrasonic waves are emitted from the bulk ultrasonic transceiver 51. Fig. 5 is a diagram showing how the emission angle of ultrasonic waves from the bulk ultrasonic transceiver 51 is changed using a wedge member 52.

[0027] As shown in Fig. 4, the bulk ultrasonic transceiver 51 emits ultrasonic waves U'. At this time, the bulk ultrasonic transceiver 51 emits the ultrasonic waves U' in the normal direction of the surface from which the ultrasonic waves are output and an equiphase surface S' parallel to the surface. For this reason, as shown in Fig. 5, a wedge member 52 is required to adjust the emission angle of the ultrasonic waves U' from the bulk ultrasonic transceiver 51.

[0028] Therefore, in a conventional ultrasonic flowmeter equipped with the bulk ultrasonic transmitter / receiver 51, the bulk ultrasonic transmitter / receiver 51 must be slid along the outer circumferential surface of the pipe 30 to search for the optimum position where ultrasonic waves U' can be transmitted and received reliably. At this time, the inclination angle of the wedge member 52 may be changed as necessary. For this reason, in a conventional ultrasonic flowmeter, there is a risk that adjusting the distance in the axial direction of the pipe between the bulk ultrasonic transmitter / receivers 51 becomes complicated every time the diameter of the pipe 30 changes.

[0029] As described above, the ultrasonic flowmeter 10 according to the first embodiment is a single-beam ultrasonic flowmeter, but may be a multi-beam ultrasonic flowmeter. In this case, the ultrasonic flowmeter 10 includes one or more pairs, i.e., multiple pairs (multiple sets) of the first phased array ultrasonic transmitter / receiver 11 and the second phased array ultrasonic transmitter / receiver 12.

[0030] A single-beam ultrasonic flowmeter measures fluid flow based on information from a single propagation path between a pair of ultrasonic transmitters and receivers. However, in a single-beam ultrasonic flowmeter, the accuracy of flow measurement decreases when the flow velocity distribution in the measurement area including the single propagation path is not uniform. For example, this occurs when a valve, pump, or pipeline bend is installed upstream of the measurement area.

[0031] Therefore, a multi-beam ultrasonic flow meter is provided to solve such problems. A multi-beam ultrasonic flow meter performs fluid measurement based on information on each propagation path between multiple pairs of ultrasonic transmitters and receivers. Therefore, a multi-beam ultrasonic flow meter can improve the accuracy of fluid measurement compared to when the flow meter performs fluid measurement based on information on a single propagation path.

[0032] Furthermore, when a pair of ultrasonic transmitters and receivers is used, the upstream straight pipe length must be "20D." "D" indicates the diameter of the pipe. For example, when using a pipe with an outer diameter of 10 cm, the ultrasonic transmitters and receivers must be installed 200 cm away from any valves or other devices located upstream of the pipe. By positioning the ultrasonic transmitters and receivers in consideration of the upstream straight pipe length, the flow velocity distribution in the measurement area becomes uniform, allowing for highly accurate fluid measurement. When the ultrasonic flowmeter 10 according to the first embodiment is a multi-beam ultrasonic flowmeter, each pair of ultrasonic transmitters and receivers can perform highly accurate flow measurement even if the upstream straight pipe length is not met.

[0033] As described above, the ultrasonic flowmeter 10 according to the first embodiment is an ultrasonic flowmeter in which one or more pair of ultrasonic transmitters and receivers 11, 12 attached to the outer peripheral surface of the pipe 30 transmit and receive ultrasonic waves to and from each other via a fluid flowing inside the pipe 30. The one or more pair of ultrasonic transmitters and receivers 11, 12 are phased array ultrasonic transmitters and receivers 11, 12 in which a plurality of ultrasonic elements 11b, 12b are arranged in an array and adjusted to an ultrasonic emission angle with respect to the axis of the pipe 30 that maximizes the received strength of the ultrasonic waves, and the distance in the pipe axial direction between the one or more pair of ultrasonic transmitters and receivers 11, 12 is fixed. Therefore, the ultrasonic flowmeter 10 does not require adjustment of the distance in the pipe axial direction between the one or more pair of ultrasonic transmitters and receivers 11, 12 even if the diameter of the pipe 30 is different.

[0034] It should be noted that, within the scope of the present disclosure, any of the components of the embodiments may be modified or omitted. [Explanation of symbols]

[0035] 10 Ultrasonic flow meter 11. First phased array ultrasonic transmitter / receiver 11a Elastic Couplant 11b Ultrasonic element 12 Second phased array ultrasonic transmitter / receiver 12a Elastic Couplant 12b Ultrasonic element 21,22 Wiring 30 Piping 51 Bulk ultrasonic transmitter / receiver 52 Wedge member

Claims

1. In an ultrasonic flowmeter, one or more pairs of ultrasonic transmitters and receivers are attached to the outer peripheral surface of a pipe, and ultrasonic waves are transmitted and received between the pair of ultrasonic transmitters and receivers via a fluid flowing inside the pipe, The one or more pairs of ultrasonic transmitters and receivers include: A phased array ultrasonic transmitter / receiver in which a plurality of ultrasonic elements are arranged in an array, the ultrasonic elements being adjusted to an emission angle of the ultrasonic waves relative to the axis of the pipe such that the reception intensity of the ultrasonic waves is maximized, The distance between the pair of ultrasonic transmitters and receivers in the axial direction of the pipe is fixed.

1. An ultrasonic flow meter comprising:

2. In a method for installing an ultrasonic flowmeter, one or more pairs of ultrasonic transmitters and receivers are attached to the outer peripheral surface of a pipe, and ultrasonic waves are transmitted and received between the pair of ultrasonic transmitters and receivers via a fluid flowing inside the pipe. The one or more pairs of ultrasonic transmitter-receivers are phased array ultrasonic transmitter-receivers in which a plurality of ultrasonic elements are arranged in an array, A distance between the pair of ultrasonic transmitters and receivers in the axial direction of the pipe is fixed, The emission angle of the ultrasonic waves emitted by the plurality of ultrasonic elements with respect to the axis of the pipe is adjusted so that the received strength of the ultrasonic waves is maximized.

1. A method for installing an ultrasonic flowmeter.

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