The research of relevant federal funding or the statement of research and development
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Embodiment
Symbol and term
Some term runs through following explanation and claim is used, in order to quote the concrete component of a system.This piece document does not expect to distinguish the title difference and the different member of not function.
In the following discussion and in the claims, term " has " and " comprising " uses with opening mode, and therefore, these terms should be interpreted into expression " including, but not limited to ".And term " connects (couple) " or " connecting (couples) " is intended to indirect or direct connection of expression.Therefore, if first apparatus is connected to second apparatus, then this connection can be by directly connecting, perhaps by realizing via indirect connection of other apparatus and jockey.
" fluid " is with express liquid (for example, crude oil or gasoline) or gas (for example, methane).
Figure 1A is the cross sectional view according to the ultrasonic flowmeter 101 of the embodiment of the invention.The pipeline section 100 that is suitable for being placed between each section of pipeline is the outer covers that are used for flowmeter 101.Pipeline section 100 has internal volume, as the stream that is used for measured fluid and have preliminary dimension that limit to measure section at flowmeter.Fluid can flow along direction 150 with velocity profile 152.Velocity 153-158 signal increases towards central authorities by pipeline section 100 fluid rates.
A pair of transducer 120 and 130 be positioned at pipeline section 100 around on. Transducer 120 and 130 is held by transducer port 125 and 135 respectively. Transducer 120 and 130 position can be by angle θ, in first length L of measuring between transducer 120 and 130, limit corresponding to second length X of the axial distance between the point 140 and 145 and corresponding to the 3rd length D of pipe diameter.In most of situations, distance D, X and L are just accurately determined during the manufacturing of flowmeter.And transducer (for example 120 and 130) can be placed on respectively apart from the specified distance of point 140 and 145, and irrelevant with meter size (being the pipeline section size).Though transducer is illustrated as recessed a little, in alternate embodiments, transducer is projected in the pipeline section.
Have path 110 with respect to center line 105 with angle θ between transducer 120 and 130, it is called as " string " sometimes.The length L of " string " 110 is the distances between the surface of the surface of transducer 120 and transducer 130. Point 140 and 145 defines the position that the acoustical signals that produced by transducer 120 and 130 entered and left the fluid that flows through pipeline section 100 import of pipeline section hole (promptly to).
Transducer 120 and 130 is preferably ultrasonic transceiver, and this shows that they all produce and receive ultrasonic signal." ultrasonic " refers in context and is higher than about 20 kilo hertzs frequency.In order to produce ultrasonic signal, piezoelectric element is excited by electricity, and piezoelectric element responds by vibration.The vibration of piezoelectric element produces crosses pipeline section and advances by fluid and arrive the ultrasonic signal of the right respective transducer of transducer.Similarly, when being subjected to ultrasonic signal and impacting, the piezoelectric element of reception and produce the signal of telecommunication, electronic device detection, digitlization and analysis that this signal of telecommunication is associated with flowmeter.Originally, downstream transducer 120 produces ultrasonic signal, and this signal is received by upstream transducer 130 then.After a while, upstream transducer 130 produces returns ultrasonic signal, and this signal is received by downstream transducer 120 subsequently.Like this, transducer 120 and 130 along string path 110, utilize ultrasonic signal 115 carry out " one one receipts " operation.During operation, this order per minute can take place thousands of times.
It is upstream or downstream to advance with respect to fluid stream that the delivery time of ultrasonic signal 115 between transducer 120 and 130 partly depends on ultrasonic signal 115.The delivery time of the delivery time ratio of (promptly along with the flow identical direction) ultrasonic signal of advancing (promptly with flow reverse) ultrasonic signal when advancing when upstream is short downstream.The upstream and downstream delivery time can be used to calculate the mean flow rate along signal path, and also can be used to the velocity of sound in the Fluid Computation.The shape of the area of section of the known flowmeter that is loaded with fluid and supposition velocity profile, then the mean flow rate that distributes on the zone in flowmeter hole can be used to determine flow through the amount of the fluid of flowmeter 101.
Ultrasonic flowmeter can have a pair of or many to transducer corresponding to one or more of paths.Figure 1B is the end view with pipeline section of diameter D.In these embodiments, pipeline section 100 is included in four string path M, N, O and P by the different level place of fluid stream.Each bar string path M-P is corresponding to two transducers that alternately are used as reflector and receiver.Control electronic device 160 also is shown, and it obtains and deal with data from four string path M-P.Four pairs of transducers corresponding to string path M-P are hidden in Figure 1B.
By can further understand the accurate arranging situation of four pairs of transducers with reference to figure 1C.In certain embodiments, four pairs of transducer port are installed on the pipeline section 100.Each to transducer port all corresponding to the independent string path of Figure 1B.The first pair of transducer port one 25 and 135 holds transducer 120 and 130 (Figure 1A).Transducer is installed with non-perpendicular angle θ about the center line 105 of pipeline section 100.Another holds the transducer that is associated to transducer port one 65 and 175 (only partly illustrating), thereby makes the string path roughly form one " X " with respect to the string path of transducer port 125 and 135.Similarly, transducer port 185 and 195 can be parallel to transducer port 165 and 175 places, but locates to be provided with at different " horizontal plane " (i.e. differing heights places in pipeline section).It is clear in Fig. 1 C that what illustrate is the 4th pair of transducer and transducer port.In conjunction with Figure 1B and 1C, these transducers make two pairs of transducers of top corresponding to string M and N to being aligned to, and two pairs of transducers of below are corresponding to string O and P.Can determine rate of flow of fluid at each bar string M-P place, obtaining the string flow velocity, and these string flow velocitys combine, in order to determine the mean flow rate on whole pipe.Though four pairs of transducers are illustrated as forming an X-shaped shape, can have more than or be less than four pairs transducer.And transducer can be arranged in same level or be certain other configuration.
Fig. 2 illustrates and is connected to and/or is positioned at assembly 200 in the transducer port (for example, 165 of Fig. 1,175).Especially, this assembly 200 is included in the wire harness 202 that has connector 204 on its far-end 205.Wire harness 202, and connector 204 especially utilize retention nut 206 and transducer outer cover 208 and are connected to transducer port (not shown in Fig. 2).Transducer assemblies 210 is electrically coupled to the connector 204 of wire harness 202 by the hole in the retention nut 206, and therefore is electrically connected to the electronic device of flowmeter.Transducer assemblies 210 is telescoped in the transducer outer cover 208 and is held nut 206 at least in part and keeps putting in place.When transducer assemblies 210 and transducer outer cover 208 engaged, the piezoelectric element 214 of transducer assemblies 210 was connected to matching layer 212 with acoustically.In transducer outer cover 208 and the transducer assemblies 210 each is discussed below successively.
Fig. 3 illustrates the perspective cross-sectional view according to the transducer outer cover 208 of the embodiment of the invention.Outer cover 208 comprises near-end 318, far-end 302 and internal volume 310.Far-end 318 is at least in part by acoustic matching layer 212 obturations.Acoustic matching layer 212 sealing far-ends 302, and the outside 314 of acoustic matching layer 212 is exposed to and flows through the spoolpiece/meter (fluid of Figure 1A-C).Screw thread 306 on the external diameter of transducer outer cover 208 allows outer covers 208 to be coupled to pipeline section (Figure 1A-C), and o ring 308 is sealed to transducer port (Figure 1A-C) with outer cover 208.In alternate embodiments, transducer outer cover 208 is soldered to transducer port (Figure 1A-C) of pipeline section.
In certain embodiments, transducer outer cover 208 is metal (for example low carbon stainless steels).In alternate embodiments, can use any material (for example high-density plastic or composite material) of the fluid pressure that can bear in the flowmeter with being equal to.In certain embodiments, the wall thickness of transducer outer cover 208 is selected as in response to the pressure differential between fluid in flowmeter and the internal volume 310 compression a little.The compression of the wall of transducer outer cover 208 helps acoustic matching layer 212 is kept putting in place in these embodiments.For example, a little to intrinsic deflection, and littler internal diameter is that acoustic matching layer provides a supporting role at the wall of acoustic matching layer back, with opposing because the lateral movement that the fluid pressure in the flowmeter causes.And, acoustic matching layer 212 being attached in the process of transducer outer cover 208, outer cover 208 is stretched (in the elastic limit of wall material), to receive acoustic matching layer 212.
In order to help that acoustic matching layer 212 is attached to transducer outer cover 208, in certain embodiments, acoustic matching layer 212 has meniscus 304 around the edge on inboard 312.Fig. 4 illustrates the cross sectional view of transducer outer cover 208, and it has further been illustrated according to the meniscus 304 of these embodiment.Especially, the meniscus 304 of acoustic matching layer 212 has increased the wall of transducer outer cover and the contact area between the acoustic matching layer 212, but preferably on the inboard 312 of acoustic matching layer 212, reserve enough surface areas, so that the acoustical coupling between the piezoelectric element (not shown in Fig. 4) of permission transducer assemblies.Therefore, transducer assemblies 210 is provided for the space of meniscus 304, guarantees that meniscus 304 does not influence connecting of piezoelectric element and matching layer 212.
The material of acoustic matching layer 212 be selected from down the group in one or more: glass; Pottery; Plastics; Glass filled plastics; Perhaps filled with carbon fibers plastics.Though some embodiment use 100% glass as acoustic matching layer, be to use the alternate embodiments of plastics can have 30% or lower glass content.With the material of acoustic matching layer irrelevant be that acoustic matching layer 212 provides the acoustical coupling between the fluid in piezoelectric element 214 and the flowmeter.According to embodiments of the invention, the acoustic impedance of acoustic matching layer between piezoelectric element 214 and flowmeter between the acoustic impedance of fluid.Utilize this piezoelectric element and flowmeter in matching layer acoustic impedance between the acoustic impedance of fluid, the quality of ultrasonic signal be improved (for example, bigger amplitude and faster rise time).Glass is the preferred material that is used for acoustic matching layer, and this is because it has desirable acoustic impedance, and is simultaneously enough firm in good acoustical coupling to be provided, and bearing the fluid pressure in the flowmeter, thereby makes piezoelectric element the fluid isolation from flowmeter to open.As a comparison, comprise that substantially the acoustic impedance of stainless matching layer is higher than the acoustic impedance of piezoelectric element, and therefore provide relatively poor acoustical coupling.In certain embodiments, the acoustic impedance of acoustic matching layer 212 about 1 and about 30,000,000 Rayleighs (MRayl) between; Perhaps alternately, acoustic impedance about 10 and about 15,000,000 Rayleighs between.
When transducer assemblies 210 was inserted in the transducer outer cover 208, the piezoelectric element 214 (Fig. 2) of transducer assemblies 210 was resisted against the inboard 312 of acoustic matching layer 212.For good acoustical coupling is provided, surface 312, the inside of acoustic matching layer 212 and outer surface 314 be substantially flat and be parallel to each other substantially.In certain embodiments, these surface flatnesses are in 0.001 inch or better, and the depth of parallelism is in 0.003 inch or better.In addition, transducer assemblies 210 is positioned such that piezoelectric element 214 is placed in the middle with respect to acoustic matching layer 212.Have as here the transducer outer cover 208 of the acoustic matching layer of discussion can be by the manufacturing of Dash ConnectorTechnology of Spokane Washington company and company's purchase from then on.
Acoustic matching layer 212 has certain thickness (along the axis shared with the remainder of transducer outer cover 208), and this thickness equals 1/4th the odd-multiple (1/4,3/4,5/4,7/4 times etc.) of the wavelength of sound that produced by piezoelectric element 214 in certain embodiments substantially.For example, consider the acoustic matching layer 212 of piezoelectric element of under the frequency of 1MHz, operating 214 and the velocity of sound with 5000m/s.The wavelength of the sound in acoustic matching layer is roughly 0.197 inch.In these embodiments, acoustic matching layer can be 0.049; 0.148:0.246, inch such as 0.344 is thick.Thin acoustic matching layer provides acoustical behavior preferably, but makes the thicker transducer outer cover 208 that can make of acoustic matching layer bear elevated pressures.Choose the optimum Match layer thickness and comprise that selection can bear the thinnest matching layer of the maximum pressure that can expect in flowmeter.
Make an uproar and make driving voltage double in order to reduce electricity, often expectation is electrically connected piezoelectric element (being discussed below) with differential mode, this means that the part that piezoelectric element is resisted against acoustic matching layer can have conductive coating.If acoustic matching layer is a metal, then Bao electrical insulator is used to be used for electric insulation between metal and the piezoelectric element 214.Therefore in order to address the above problem, in certain embodiments, acoustic matching layer 212 is an electrical insulator, has reduced or has eliminated needs for other electric insulation.
Forward integrated transducer assembly 210 now to.Fig. 5 illustrates the perspective view according to the transducer assemblies 210 of the embodiment of the invention.Transducer assemblies 210 comprises the elongated outer cover 501 that has along the axis 505 of its prolonging direction, and in certain embodiments, elongated outer cover 501 comprises first 500 and second portion 502, and each part all has common axis 505.In these embodiments, second portion 502 is connected to first 500 in scalable mode, thereby makes first 500 and second portion 502 to move relative to each other along axial direction.And elongated outer cover 501 can have cylindrical shape, but also can adopt other shape comparably.
Comprise among the embodiment of first 500 and second portion 502 that at elongated outer cover 501 second portion 502 is basic identical at the external diameter of the external diameter at piezoelectric crystal or far-end 518 places and first 500.Yet second portion 502 also comprises the diameter parts 520 that reduces, and this diameter parts is telescoped in the internal diameter of first 500, and therefore has the external diameter of the internal diameter that is slightly smaller than first 500.In certain embodiments, the length that engages of first and second portion 500 and 502 is substantially equal to this external diameter, but can adopt longer and shorter bonding length with being equal to.The external diameter of elongated outer cover 501 is slightly smaller than the internal diameter of transducer outer cover 208, and this is convenient to guarantee to know exactly the position of piezoelectric element.
According to some embodiment, second portion 502 (for example, Ultem1000) is made by plastics.In these embodiments, the axial length of second portion 502 reduces (to be compared with the axial length of first 500, first is preferably metal), this is because shorter length has reduced manufacturing cost, and when being made by plastic material, second portion 502 is easy to absorb moisture and expansion.The expansion of second portion 502 allows, although and expand, the axial length that reduces second portion 502 makes it possible to transducer assemblies 210 is removed from transducer outer cover 208.
The relative rotary motion of first and second portion 500 and 502 and axial displacement have been subjected to the restriction of the pin 506 that radially extends from second portion 502 by the hole 504 in the first 500.In certain embodiments, use three such pins and aperture combination, but can use as few as with being equal to one and more than three pin and aperture combination.Alternately, second portion 502 can be designed to have and hole 504 interactional lug bosses, and it is as the integral part of second portion 502.
When piezoelectric element 214 is connected to and during the first end 503 of inaccessible at least in part elongated outer cover 501, electrical prongs retainer 508 is connected to and the second end 509 of inaccessible at least in part elongated outer cover 501.The first 500 of elongated outer cover 501 can comprise connecting key 514, and this guarantees that the integrated transducer assembly is by suitably directed, so that be connected to the keyway of connector 204.Electrical prongs retainer 508 can comprise joint connecting key 514, the slit 515 to prevent that electrical prongs retainer 508 from rotating in elongated outer cover 501.In addition, electrical prongs retainer 508 also can comprise anti-rotation slit 516, and this anti-rotation slit combines with tab on the transducer outer cover 208, prevents that integrated transducer assembly 210 from rotating in transducer outer cover 208.The second end 509 of elongated outer cover 501 has the internal diameter that the little external diameter with pin retainer 508 is slidingly matched.Pin retainer 508 can be made by Ultem1000 ideally, but also can use any hard non-conducting material.
Fig. 6 illustrates the perspective cross-sectional view of transducer assemblies 210.In at least some embodiment, piezoelectric element 214 and transducer outer cover 208 electric insulations, and therefore at least second portion 502 make by aforesaid hard non-conducting material.Thereby the external diameter of the internal diameter of elongated outer cover 501 and piezoelectric element 214 is selected to and makes have certain space between transducer assemblies 210 and transducer outer cover 208, and transducer assemblies 210 is inserted in this space.It is local that this space is that the gap of the meniscus 304 (Fig. 3 and 4) that is used for acoustic matching layer provides.This space also provides local for being applied to piezoelectric element 214 surfaces before can be in inserting transducer outer cover 208 so that improve the too much oil or the grease of the acoustical coupling of piezoelectric element 214 and acoustic matching layer 212.
Shoulder 600 in elongated outer cover 501 is resisted against piezoelectric element 214, with the axial motion of opposing piezoelectric element, and for example active force that when transducer assemblies 210 is installed in the transducer outer cover 208, applies and the axial motion that causes.Volume in piezoelectric element 214 back comprises back matching layer 602 (for example, epoxy resin, powder filling epoxy resin, rubber, powder filled rubber), and is used for multiple purpose.For example, back matching layer is received elongated outer cover 501 with piezoelectric element 214 and the one or more of connecting wires that are attached to piezoelectric element 214.Especially, singing (ringing) and the bandwidth that the increase acoustic signal acoustics output that improves piezoelectric element 214 of the quality of back matching layer by reducing acoustic signal.In certain embodiments, the length of back matching layer (along the shaft centerline measurement of elongated outer cover to) thus be selected to and make the round traveling time of ultrasonic signal in matching layer 602 take place with the time longer than the Measuring Time of received signal.For example, if the 4th zero crossing in received signal is used as measurement point, then come and go the time that traveling time will preferably be longer than two circulations under the piezoelectric element center frequency of operation.Perhaps, under the piezoelectric element center frequency of operation, the length of back matching layer 602 be the sound of back in the matching layer about 1 to about 9 wavelength.Suitable length has guaranteed to transmit in the timing at the signal of ultrasonic flowmeter, and the acoustic signal of any reflection does not arrive piezoelectric element.
Further consider the elongated outer cover 501 that comprises first 500 and second portion 502, the diameter parts that reduces 520 of second portion 502 comprises shoulder 608.This shoulder enough little, allowing the hole of lead by wherein, and allow to be used to inject the opening of back matching layer 602.Back matching layer can utilize the syringe with little plastic tip to inject.On the end of this shoulder 608, be provided with the inclined-plane, to guarantee can not form any sharpened edge with damage wires.Shoulder 608 is in such position, and when bias voltage second portion 502, bias mechanism (being discussed below) can promote on this position.
Comprise that at elongated outer cover 501 transducer assemblies 210 comprises bias mechanism among the embodiment that allows mutual axially movable first 500 and second portion 502, for example spring 610.Bias mechanism along common axis X bias voltage first 500 and second portion 502 mutually away from.Bias mechanism bias voltage first 500 and second portion 502 mutually away from active force be about 4 pounds to about 12 pounds in certain embodiments.In alternate embodiments, bias mechanism can provide any mechanism of biasing force, for example packing ring, sheet rubber, or the combination of spring, packing ring and/or sheet rubber.
At assembly process, spring 610 is leaned shoulder 618 compressions a little, and at least one pin (partly being shown in 506 places) and aperture combination (Fig. 5) limit second portion 502 in first 500 axial motion and rotatablely move.In case transducer assemblies 210 is mounted, then transducer outer cover 208, retention nut 206 (Fig. 2) are further compressed spring 610.This compression has compensated the tolerance of institute's assembling parts, guarantees that the outside of piezoelectric element 214 well contacts (Fig. 4) with inboard 312 formation of acoustic matching layer 212.In case connector 204 (Fig. 2) is assembled good, then spring 610 can further be compressed.In case connector 204 puts in place, then elastic force can have 4.9 pounds magnitude.In alternate embodiments, connector 204 must not apply further compression stress on spring.At elongated outer cover 501 is among the embodiment of single structure, is used to guarantee that the active force of the good anastomosis (Fig. 4) between piezoelectric element 214 and acoustic matching layer 212 can be provided by retention nut 206 (Fig. 2) and/or connector 204 (Fig. 2).
Pin retainer 508 is connected pin 610 and 612 with two of the length maintenances of required interval and exposure.These pins cooperate with connector 204, thereby being electrically connected of transducer assemblies and flowmeter electronic device is provided.Electrical prongs 610 is utilized first lead 611 of the inside that extends through elongated outer cover 501 and is connected to piezoelectric element 214.Similarly, second pin 612 utilizes second lead 613 of the inside that also extends through outer cover 501 and is connected to piezoelectric element 214.In certain embodiments, the multiply copper conductor with PTFE insulating barrier is used to lead 611,613, but also can use the lead of other type with being equal to.For lead 611 and 613 is kept putting in place, and the resistor 614 (being discussed below) that may exist and 508 maintenances of electrical prongs retainer put in place, and binding agent 609 (for example epoxy resin) is inserted in the epoxy resin fill port 612.In certain embodiments, connecting pin 610 and 612 is firm gold plated copper pins, and this pin has the welding recess, but also can use other pin with being equal to.Adopted the wire insulation of two kinds of different colours, be used to guarantee the correct polarity on piezoelectric crystal surface during manufacture, and the connecting key on the housing be connected pin orientation and kept.Lead is twisted at assembly process, and to guarantee that the signal of telecommunication of any induction is balanced in lead, sort signal disturbs the crystal pulse during measuring period to avoid.
Therefore the resistor 614 that has connected one one megohm between pin 610 and 612 has connected two electrode plated faces (being discussed below) of piezoelectric crystal.This resistor 614 provides the short circuit under the low frequency, in order to discharge by carry or installation period between mechanical shock or variations in temperature and any electric energy of producing.High transducer frequency of operation (~1MHz) under, resistor 614 in fact for the signal of telecommunication that is sent to or produces by piezoelectric crystal without any influence.A lead-in wire of this resistor is insulated pipe insulation, with the short circuit of avoiding going between during manufacture with shell.Alternative transducer designs can comprise the other electronic device (for example, inductor, amplifier, switch, voltage stabilizing didoe, perhaps capacitor) that is arranged in the integrated transducer assembly.Can be individually or combinedly use these devices.
Fig. 7 A and 7B signal according to the embodiment of the invention with the electrically connecting of piezoelectric element 214.In certain embodiments, piezoelectric element 214 is piezoelectric crystals, for example PZT-5A or other similar material.The thickness of piezoelectric crystal and diameter are being controlled the frequency of the ultrasonic signal that is launched.The outside 700 is sides that are connected to acoustic matching layer (Fig. 3 and 4) of piezoelectric element 214.The outside 700 of piezoelectric element and inboard 702 is coated with silver or other metal at least in part, to form electrode surface.A part 704 of the electrodeposited coating on the outside 700 extends to inboard 702 around the periphery of piezoelectric crystal.The electrodeposited coating of the electrodeposited coating in the outside 700 (comprising part 704) and inboard 702 is by zone 706 electric insulations that do not have electrodeposited coating.Electroplate the inboard 702 that makes it possible to lead 611 and 613 all is connected to piezoelectric element 214 in this way.The coating of being illustrated arranges that it is smooth allowing the outside 700, so that form good the contact with acoustic matching layer.Perhaps, a lead can and be connected to the outside 700 around the piezoelectric element extension.In these embodiments, the part of outer cover 501 (Fig. 5 and 6) has recess, so that allow lead to pass through.And a lead directly is connected among these embodiment of outer surface 700 therein, and acoustic matching layer 214 has recess, in order to hold lead.In another embodiment, first connecting wire is received the inboard 702 of piezoelectric element, and second connecting wire is received the periphery or the edge of piezoelectric element.
The installation and the replacing of this transducer assemblies 210 designs greatly simplification transducer assemblies are especially in the installation and the replacing at condition (lightning, weather etc.) dissatisfactory pipeline facility place.With reference to the flow chart among the figure 8, in various embodiments, the method 800 of changing transducer assemblies may further comprise the steps: disconnect that (Figure 1A-C) is electrically coupled to the rat tail (square frame 802) of transducer assemblies 210 with the electronic device of ultrasonic flowmeter.If used, then bias mechanism is disengaged (square frame 803), for example by unclamping and removing nut 206 (Fig. 2).After this, transducer assemblies 804 is removed (square frame 804) as independent unit from transducer outer cover 208.The transducer assemblies of changing is same to be inserted in the transducer outer cover (square frame 806) as independent unit.In certain embodiments, for example, retention nut 206 engages bias mechanism (square frame 807) by being installed.At last, wire harness is reconnected (square frame 808).
Though illustrated and described each embodiment of the present invention, those skilled in the art can make improvements it, and can not deviate from spirit of the present invention or instruction.Here the embodiment of Miao Shuing only is illustrative rather than restrictive.Therefore, the embodiment that protection range is not limited to here describe, but only by the restriction of subsequently claim, the scope of claim should comprise all equivalents of claim theme.