Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
  • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
  • G01F1/66—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters
  • G01F1/662—Constructional details
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
  • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
  • G01F1/66—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters
  • G01F1/667—Arrangements of transducers for ultrasonic flowmeters; Circuits for operating ultrasonic flowmeters

Definitions

• the invention relates to an ultrasonic flow meter and a method for manufacturing an ultrasonic flow meter according to the claims.
• ultrasonic flow meters have become increasingly popular, e.g. due to the advantage that the detection system is not a mechanical detection system with rotating parts.
• One particular type of ultrasonic flow meter is the transit time flow meter, which transmits an ultrasound signal between two ultrasound transducers to establish the flow rate.
• reflector clamping members may be used to clamp the reflectors to the insert.
• An example of this is shown in WO 2017/215716 Al.
• the clamping member comprising a flexible portion for contacting the reflector, a fixation portion for fixating the clamping member to the flow conduit insert, and optionally a joining portion for joining the aforementioned portions.
• the flexible portion supports one side of the reflector thereby clamping the reflector between the clamping member on one side and the insert on the other side. Thereby, no additional components are needed to fixate the reflector to the insert.
• a snap-fit example where the flexible portion is formed by elastic pins providing a clamping force by deforming in a direction away from the flow conduit insert.
• the clamping member is fixated only to the insert.
• the flexible portion, the fixation portion, and the joining portion are monolithic.
• the flexible portion, monolithic with the joining and fixation portions may be formed from materials such as plastics, metals, and composite materials, and may be formed as elastic pins.
• the flexible portion comprises an elastic material different from the material of the joining portion, if any, and/or from the material of the fixation portion.
• Such elastic material may be rubber or a rubber-like material, whereas the joining portion and/or the fixation portion may be made from e.g. polyethylene, polyethylene terephthalate, or a metal.
• the fixation portion may fixate the clamping member to the insert by means of a snap-fit fixation, or alternative by an adhesive or by ultrasonic welding.
• the fixation of the reflector may not endure certain situations, which from time to time occurs in many water piping systems. Examples may include high pressure surges, very high flow rate, etc. Therefore, there may be a risk that the fixation of the reflector is temporarily or permanently compromised due to such events. Resultingly, the path of the ultrasonic signal, and thus the precision of the ultrasonic flow meter, may become negatively affected. Also, a problem may exist in ensuring sufficient fixation of the insert in the flow conduit.
• the invention relates to an ultrasonic flow meter comprising a housing holding a first and a second ultrasound transducer, a flow conduit having a flow conduit inner surface, a flow conduit insert being positioned inside the flow conduit and having an insert outer surface facing the flow conduit inner surface, an ultrasound reflector having a first reflector side and a second, opposite reflector side, the first reflector side facing the flow conduit insert and the second reflector side facing the flow conduit, the reflector being arranged for reflecting an ultrasound signal emitted from the first ultrasonic transducer along a predefined path within the insert to the second ultrasonic transducer, and vice versa, and a clamping unit arranged to fixate the ultrasound reflector to the flow conduit insert and having a first clamping unit side and a second, opposite clamping unit side, the first clamping unit side facing the ultrasound reflector and the second clamping unit side facing the flow conduit, the first clamping unit side contacting the second reflector side, characterized in that the second clamping unit side is contacting the flow conduit inner surface so as to
• the reflector is not only clamped by the clamping unit itself but is clamped between the flow conduit insert and the flow conduit. This allows a more effective fixation, since any strength of the clamping unit is not a limiting factor, as the clamping unit itself may be clamped between the flow conduit on one side and the flow conduit insert and reflector on the other side, whereby the force from the flow conduit itself on the clamping unit may be transferred to the reflector.
• a further advantage of the invention may be that the flow conduit insert is fixated in the flow conduit insert by means of the clamping member contacting the flow conduit insert.
• the flow conduit insert may be fixated relative to the flow conduit.
• the meter comprises further measures for providing fixation of the flow conduit insert, this may be beneficial both in terms of assembly, since the flow conduit insert may thus be fixated immediately after being inserted into the flow conduit, but also with respect to durability, since any wearing of such other measures, if present, may at least in part be absorbed by the fixation provided by the clamping unit.
• An advantage of clamping the ultrasound reflector between the flow conduit insert and the flow conduit is that the reflector may be positioned off-center with respect to the flow conduit and thereby minimize flow disturbance induced by the reflector itself and its fixation.
• the flow conduit insert may restrict the inner space of the flow conduit through which the fluid to be measured can flow.
• the flow velocity of the fluid may be increased locally without inducing too much pressure drop of the fluid across the length of the flow conduit insert.
• Having an increased flow velocity between the transducers may beneficially increase the accuracy of the measurement of the flow velocity and hence increase the accuracy of the fluid flow calculated on the basis of the measured flow velocity. This increased accuracy may be especially pronounced at lower flow rates, i.e. when the volume of fluid per unit of time is relatively low.
• the increased accuracy could also be used to exchange electronic components into more cost-conserving versions, without losing accuracy, due to the implemented flow conduit insert.
• the flow conduit insert comprises a first and a second, opposite, flow opening connected to each other to form an inner space to allow passage of the fluid for which flow is measured.
• the insert, the clamping unit(s), the reflector(s) are different parts. Also, these parts are different from the flow conduit, into which the insert is positioned.
• the ultrasonic flow meter is understood to be adapted to measure a flow of a fluid through said flow conduit.
• the fluid is a liquid, such as water.
• the ultrasonic flow meter may for example be a transit-time ultrasonic flow meter. It is noted that the ultrasound reflector is configured to be reflective for the applied ultrasound, particularly that the first reflector side is reflective for the ultrasound signal emitted by the ultrasonic transducers.
• the flow conduit insert has a reflector opening, and wherein the ultrasound reflector is arranged in the reflector opening.
• said reflector opening of the flow conduit insert is an opening facing outwards, i.e. away from the longitudinal center axis of the insert.
• the reflector opening may be formed as a through-going hole having a suitable neck for contacting the first reflector side, e.g. along the edges thereof, or having at least a suitable number of contacting points for contacting the first reflector side.
• the neck or contacting points may serve to support the reflector and provide an outwards directed force matching the force of exerted by the clamping unit on the second reflector side.
• a part of the first clamping unit side contacts the insert outer surface.
• this may be implemented e.g. by allowing the clamping unit to have a greater area than the reflector.
• the flow conduit insert comprises at least one region made of a material having an acoustic impedance of 1.0 to 2.0, such as 1.2 to 1.8, such as 1.4 to 1.6.
• an advantage of the above embodiment may be that the region may be at least partly transparent for ultrasound due to matching of its acoustic impedance with the fluid.
• the said region may be used as an alternative to a reflector opening.
• the at least one region made of a material selected from polyethylene, styrene butadiene, dimethyl pentene polymer, ethyl vinyl acetate, polyurethane, divinyl olefin-based polymers, or combinations thereof.
• the clamping unit having an uncompressed state and a radially compressed state, the radially compressed state having a thickness of the clamping unit being reduced by compression in the radial direction relative to the longitudinal center axis of the flow conduit, wherein the clamping unit is its radially compressed state when fixating the ultrasound reflector between the flow conduit insert and the flow conduit.
• the term radially compressed state is understood in relation to the following.
• the clamping unit can be in an un-tensioned or uncompressed stated before assembling, or if the meter is assembled, the clamping unit may be brought into this uncompressed state by disassembling the meter.
• the radially compressed state refers to an assembled state, which the clamping unit is brought into when the flow meter is assembled.
• the clamping unit In the ultrasonic flow meter, the clamping unit is in the radially compressed state between the ultrasound reflector and the flow conduit, i.e. between the ultrasound reflector and the walls of the flow conduit. Thereby, it exerts a radial force on the ultrasonic reflector so as to fixate the ultrasound reflector in the flow conduit insert.
• the present inventors have found that this way, an improved clamping force can be obtained, since the clamping unit itself is clamped between the flow conduit and the ultrasound reflector, and therefore is able to provide an improved fixation of the ultrasound reflector in a relatively simple manner.
• an advantage of the above embodiment may be that an effective fixation of the at least one ultrasound reflector is obtained by means of the radially compressed clamping unit exerting a force on the at least one ultrasound reflector in radial direct towards the center of the flow conduit.
• the fixation of the ultrasound reflector can be efficient enough to withstand even powerful pressure surges, which may sometimes occur in water piping systems, and which may otherwise dislodge reflectors from their fixation.
• the improved clamping force is thus provided by the clamping member itself being clamped between the reflector on one side and the flow conduit on the opposite side.
• a further advantage of the above embodiment may be that the flow conduit insert is at least partly fixated in the flow conduit due to the clamping units exerting a force on the flow conduit.
• the clamping unit is radially compressible and that it forms part of the ultrasonic flow meter in the radially compressed state.
• the clamping unit is configured to have a first radial thickness in a uncompressed state and to have a second radial thickness in a radially compressed state, where the second radial thickness is lower than the first radial thickness.
• the first side of the clamping unit is contacting the flow conduit insert.
• the clamping unit is configured to fixate the flow conduit insert inside the flow conduit.
• An advantage of the above embodiment may be that by fixating the flow conduit insert in the flow conduit, the position of the ultrasound reflectors may be accurately fixated and thereby ensure a precise ultrasound path. This in turns may facilitate an accurate flow determination of the ultrasonic flow meter.
• the clamping unit comprises one or more fixation parts for at least partly fixating the clamping unit to the flow conduit insert.
• the one or more fixation parts are adapted to longitudinally fixate the clamping unit relative to the flow conduit insert. In an embodiment of the invention, the one or more fixation parts are adapted to rotationally fixate the clamping unit relative to the flow conduit insert.
• the one or more fixation parts comprises at least one depression or through-hole
• the flow conduit insert comprises a corresponding protrusion for engaging the depression or through-hole
• flow conduit, the flow conduit insert, and the ultrasound reflector defines a radial distance between the second reflector side and the flow conduit inner surface, wherein the clamping unit has an uncompressed state and a radially compressed state, and wherein the clamping unit it its uncompressed state has a radial thickness exceeding said radial distance.
• said radial distance between the ultrasound reflector and the flow conduit is the free space distance between the ultrasound reflector and the flow conduit if the clamping unit is removed.
• the un-tensioned thickness refers to the thickness of the clamping unit e.g. before assembling the flow meter, or alternatively after disassembling the meter.
• the thickness is in a dimension corresponding to a radial dimension after the flow meter is assembled.
• the second radial thickness in the radially compressed state corresponds to said radial distance.
• the clamping unit is configured to ensure clamping of the ultrasonic reflector by continuously providing a radial force due to the radial compression of the clamping unit after assembly.
• the uncompressed radial thickness exceeds said radial distance by at least 5% of said radial distance, such as at least 10% of said radial distance.
• the uncompressed radial thickness exceeds said radial distance by 5 - 30% of said radial distance, such as 10-20% of said radial distance.
• the uncompressed radial thickness exceeds said radial distance by at least 0.05 mm, such as at least 0.10 mm.
• the uncompressed radial thickness exceeds said radial distance by 0.05 mm, such as at least 0.10 mm.
• the flow conduit insert comprises or consist of a polymeric material, such as a fiber reinforced polymeric material.
• the reflector is clamped between the clamping unit and the at flow conduit insert.
• the clamping unit comprises an elastic material.
• An advantage of the above embodiment may be that by using an elastic material, a sufficient fixation of the ultrasound reflector may be obtained.
• the clamping unit is monolithic.
• an advantage of the above embodiment may be that manufacturing of the clamping unit may be simplified and a more cost-effective manufacturing therefore may be obtained.
• the term “monolithic” refers to a part being formed as one part, e.g. by casting as one part.
• the monolithic clamping unit is not formed by joining two or more parts, and therefore is without joints or seams.
• the term unipartite may also be used interchangeably with monolithic.
• the clamping unit consists of an elastic material.
• the clamping unit comprises or consists of a material selected from the group consisting of silicone rubber, EPDM rubber, and any combination thereof.
• the clamping unit comprises or consists of a material having a Shore hardness A of no more than 100, such as no more than 80.
• An advantage of the above embodiment may be that the clamping unit has the desired properties, such as hardness and elasticity, to on one side be able to deform sufficiently to allow assembly and on the other hand ensure a sufficient fixation force on the ultrasound reflector and the flow conduit insert.
• the clamping unit comprises or consists of a material having a Shore hardness A of 1 - 100, such as 50 - 80, such as 65-75.
• the shore hardness A is measured in accordance with ASTM D 2240 Type A.
• the clamping unit comprises or consists of a material having a Young’s modulus of no more than 2.0 gigapascal, such as no more than 1.0 gigapascal, such as 0.5 gigapascal, such as no more than 0.2 gigapascal.
• a Young’s modulus of no more than 2.0 gigapascal such as no more than 1.0 gigapascal, such as 0.5 gigapascal, such as no more than 0.2 gigapascal.
• the clamping unit comprises or consists of a material having a Young’s modulus of 0.000005 to 2.0 gigapascal, such as 0.0005 to 1.0 gigapascal, such as 0.001 to 0.5 gigapascal, such as 0.005 to 0.2 gigapascal.
• the invention further relates to a method for manufacturing an ultrasonic flow meter, the ultrasonic flow meter comprising a flow conduit, a flow conduit insert, an ultrasound reflector, and a clamping unit, the method comprising the steps of arranging the ultrasound reflector with the flow conduit insert, arranging the clamping unit with the ultrasound reflector, inserting the flow conduit insert with the ultrasound reflector and the clamping unit into the flow conduit so as to fixate the ultrasound reflector by clamping it between the flow conduit insert and the flow conduit.
• An advantage of the invention may be that a relatively simple manufacturing method may be obtained, while at the same time facilitating a fixation of the ultrasound reflector, which can be both strong and durable.
• the flow conduit insert has a reflector opening, and wherein the ultrasound reflector is arranged in the reflector opening.
• the method further comprises a step of reducing the radial thickness of the flow conduit insert with the ultrasound reflector and the clamping unit prior to the step of inserting.
• the ultrasonic flow meter is according to the invention or any of its embodiments.
• Figure 1 illustrates an ultrasonic flow meter UFM according to an embodiment of the invention
• FIG. 2A and 2B illustrate flow conduit insert FCI, three ultrasound reflectors REF and corresponding clamping units CLU are illustrated according to an embodiment of the invention
• Figure 3 illustrate a part of an ultrasonic flow meter UFM with an ultrasound signal path USP according to an embodiment of the invention
• FIGS. 4A and 4B illustrate clamping units CLU with a corresponding reflector REF according to an embodiment of the invention
• FIGS. 5A-5D illustrate clamping units CLU with a corresponding reflector REF according to an embodiment of the invention
• Figure 6 illustrates an ultrasonic flow meter UFM according to an embodiment of the invention.
• an ultrasonic flow meter UFM according to an embodiment of the invention is illustrated in an exploded view.
• the ultrasonic flow meter UFM comprises a housing HOU, which, in assembled configuration, holds a first ultrasound transducer UT1 and a second ultrasound transducer UT2.
• the meter UFM further comprises a flow conduit FC, a flow conduit insert FCI, an ultrasound reflector REF (not shown in figure 1), and a clamping unit CLU.
• the flow conduit FC, the flow conduit insert FCI, the ultrasound reflector REF, and the clamping unit CLU are also illustrated in an exploded view in figure 6.
• the flow conduit FC has a flow conduit inner surface CIS.
• the flow conduit insert FCI has an insert outer surface IOS.
• the insert outer surface faces the flow conduit inner surface CIS.
• the ultrasound reflector REF has a first reflector side RFS and a second, opposite reflector side RSS.
• first reflector side RFS faces the flow conduit insert FCI whereas the second reflector side RSS faces the flow conduit FC.
• the reflector REF is arranged to reflect an ultrasound signal emitted from the first ultrasonic transducer UT1 along a predefined path USP within the insert FCI to the second ultrasonic transducer UT2, and vice versa. This is illustrated in figure 3, where three ultrasound reflectors REF are used.
• the clamping unit CLU has a first clamping unit side UFS and a second, opposite clamping unit side USS.
• the clamping unit CLU When in assembled configuration, the clamping unit CLU is arranged to fixate the ultrasound reflector REF to the flow conduit insert FCI, as described in the following.
• the first clamping unit side UFS faces the ultrasound reflector REF and the second clamping unit side USS faces the flow conduit FC. Additionally, the first clamping unit side UFS is in contact with the second reflector side RSS. Finally, the second clamping unit side USS is in contact with the flow conduit inner surface CIS. Thereby, the clamping unit CLU fixates the ultrasound reflector REF by clamping it between the flow conduit insert FCI and the flow conduit FC.
• the housing HOU is further shown to hold a control unit CU, which may be configured to operate and control the ultrasonic transducers, perform calculations based on received signals therefrom, etc.
• the control unit CU may in some embodiments also comprise a display unit for displaying flow measurements and/or other parameters.
• the control unit CU may in some embodiments comprise a communication unit for wired and/or wireless communication. Wireless communication may be short range, such as near field communication (NFC) or Bluetooth, or long-range radio signals.
• NFC near field communication
• Bluetooth Bluetooth
• a flow conduit insert FCI, three ultrasound reflectors REF and corresponding clamping units CLU are illustrated in accordance with an embodiment of the invention.
• FIG 2A shows an exploded view. As can be seen, three ultrasound reflectors REF are shown and for each reflector REF a corresponding clamping unit CLU. The clamping units are then inserted over the ultrasound reflectors REF, e.g. as described in relation to figures 1 and 6.
• the clamping unit CLU may comprise one or more through-holes DH in the clamping unit CLU.
• the clamping unit CLU of figure 2A has two through-holes DH.
• the one or more through-holes DH are positioned so as to be engaged by corresponding protrusions IPR formed on the flow conduit insert FCI.
• Figure 2B illustrating the assembled configuration, shows the protrusions IPR engaged and fitting into the through holes DH.
• the clamping unit CLU may comprise one or more depressions DH instead of the through-holes DH.
• Figure 2B shows an assembled view, where the flow conduit insert FCI, the reflectors REF, and clamping units CLU have been fitted together and ready for being inserted into the flow conduit FC.
• clamping units CLU and correspond reflectors REF are shown according to embodiments of the invention.
• FIG 4A a clamping unit CLU having the clamping unit first side UFS facing upwards towards the reflector REF, is shown.
• the reflector second side RSS faces the clamping unit CLU, whereas the reflector first side RFS faces away.
• the clamping unit first side UFS has a non-horizontal orientation, such that when the reflector second side RSS is brought into contact with the clamping unit first side UFS, the reflector REF will be non-horizontally oriented.
• FIGS 5A-5D also illustrating pairs of clamping units CLU and reflectors REF.
• figures 5B and 5D show a cross-section of figure 5A and 5C, respectively.
• figures 5A and 5B may correspond to the embodiment illustrated in figure 4A, where the reflector REF is non-horizontally oriented when the clamping unit CLU is horizontally oriented.
• figures 5C and 5D may correspond to the embodiment illustrated in figure 4B, where the reflector REF is horizontally oriented when the clamping unit CLU is horizontally oriented.
• the reflector REF and corresponding clamping unit CLU of figure 4A and 5 A-5B may be used as the first and third reflector REF as seen along the ultrasound path USP (right and left reflector REF of figure 3), whereas the reflector REF and corresponding clamping unit CLU of figure 4B and 5C-5D may be used as the second reflector REF, i.e. the middle reflector as shown in figure 3.
• the ultrasound path USP may be optimally constructed to have middle segments, extending from reflector to reflector, having a lower angle relative to a longitudinal axis of the flow conduit insert when compared to the outer segments, extending from the first transducer TRI to the first-coming reflector REF (left reflector in figure 3) and extending from the second reflector TR2 to the first-coming reflector REF (right reflector in figure 3).
• FIGS. 4A-4B and 5 A-5D illustrate one way of designing the clamping units in order to obtain different orientation of the ultrasound reflectors with respect to a center axis of the flow conduit insert.
• identical clamping units CLU may be used.
• the path of the ultrasound is supported, i.e. such that the ultrasound signal emitted from the first ultrasonic transducer is directed by the one or more ultrasound reflector(s) along a predefined path within the insert to the second ultrasonic transducer, and vice versa.

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• Physics & Mathematics (AREA)
• Electromagnetism (AREA)
• Fluid Mechanics (AREA)
• General Physics & Mathematics (AREA)
• Measuring Volume Flow (AREA)

Applications Claiming Priority (1)

Publications (1)

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Family Applications (1)

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• 2021
  • 2021-12-22 EP EP21835577.4A patent/EP4453516A1/de active Pending
  • 2021-12-22 WO PCT/DK2021/050381 patent/WO2023116995A1/en not_active Ceased

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