CN1058565C - Improved stability coriolis mass flow meter - Google Patents

Abstract

An optimized Coriolis mass flow meter is disclosed which has improved stability to excitations caused by external influences. A primary source of improvement involves determining by modal analysis of the flow conduit a location for the sensor means that minimizes the influence of external excitation of one or more of the first in phase bending mode, the first out of phase bending mode, the first out of phase twist mode, the second out of phase twist mode, the second out of phase bending mode and the third out of phase bending mode.

Description

Coriolis mass flowmeter

The application is that we extend in the part of the U.S. Patent application (series number 364,032) of submission on June 9th, 1989.

In the prior art of relevant measurement stream material mass velocity, known: as can to induce coriolis force (Coriolis forces) by Oscillation Flows pipeline streaming flow, this power can be transverse to fluid flow direction basically and on this direction of axis of vibration takes place for it pipeline reversed, and also knows: the angular velocity the when mass velocity of the size of this coriolis force and the fluid that flows through pipeline and pipe whip is relevant.

Past is must accurately measure or angular velocity that accurate control oscillatory flow is threaded a pipe with being devoted to design and make a relevant technical problem underlying of Ke Shi mass velocity instrument aspect, like this, the effect that can utilize the measurement coriolis force to cause calculates the mass velocity of the fluid that flows through circulation duct.Even the angular velocity of circulation duct can accurately be determined or control, precision measurement can cause another serious problems by the size of the effect that coriolis force causes.Producing the size in part because of the coriolis force that produces of this problem, compare with damping with other power such as inertia, is very little, so the effect that final coriolis force causes is very little.In addition, because coriolis force is less, so by the vibration of external force as being caused by the machinery of for example adjacency or the pressure surge in the fluid line, the effect that causes can cause the mensuration to the mistake of mass velocity.These are as the uncontinuity of circulation duct, and the instability of pipeline is installed, and use lacks the error source of pipeline of mechanical repeatability flexural property or the like, have usually covered the effect that is caused by the coriolis force that produces fully, have weakened the actual use of mass flowmeter greatly.

(name is called " method of flow measurement and structure ", the patent No. is that Re 31450 and date of publication are November 29 nineteen eighty-three at several United States Patent (USP)s; Name be called " mass flow measurement methods and device ", the patent No. be 4422338 and date of publication be Dec 27 nineteen eighty-three; And, name be called " parallel channels Ke Shi mass velocity meter ", the patent No. be 4491025 and date of publication be on January 1st, 1985) in, physical construction and measuring technique are disclosed, also disclose its other advantages, promptly (a) needn't measure or control the size of the angular velocity that the oscillatory flow of Ke Shi mass velocity meter threads a pipe; (b) be provided for measuring necessary sensitivity of effect and the precision that coriolis force causes simultaneously; (c) reduce susceptibility to the error that occurs in many tentative mass flowmeters in early days.The mechanical hook-up that is disclosed in these patents contains crooked continuous flow pipeline, and they are to insensitive joint of pressure or pipeline section, as corrugated tube, and elastomer connector or other pressure distortion part.These circulation ducts are installed securely at their inlet end and endpiece place, their the sweep support that overhangs out.For example, in flowmeter according to above-mentioned arbitrary patent, communicating pipe is welded or is brazed on the support, like this, around some axis vibration, these axis are located substantially on the adjacent part of firm mounting points with circulation duct in the spring-like mode for they, or as disclosed in United States Patent (USP) 4491025, these axis are located substantially on the position of firm connection brace apparatus, and wherein strut is used for being positioned on the position of mounting points two or many pipeline firm grip.

According to setting up circulation duct like this, produce a kind of machine performance, promptly under current intelligence, the power of resisting mutually with the coriolis force that produces in oscillatory flow is threaded a pipe is essentially Hookean spring power.With Hookean spring power basically mutually the antagonism coriolis force, the oscillatory flow that contains streaming flow is threaded a pipe produces deflection or reverse around some axis, wherein the position of these axis between and equidistant in those parts those circulation ducts, that can show coriolis force.Deflection is the coriolis force that produces and with respect to the function of the size of the Hookean spring power of coriolis force.In addition, these are firmly installed, continuous flow pipe design must make they, be different from around the resonant frequency of all vibration axis (being positioned at frame or strut place place substantially), preferably be lower than resonant frequency, have an effect with respect to these axis coriolis forces around other axis.

Disclosing bend flow many kinds of given shapes, that firmly install in the prior art threads a pipe.Wherein generally included the U-shaped pipeline, " arm of these pipelines is to assemble, disperse or crooked basically " (United States Patent (USP) Re 31450, the 5 row, the 10th to 11 row).Also disclose circulation duct straight, that firmly install in the prior art, their general work principle and crooked pipeline identical.

As mentioned above, produce coriolis force when fluid flows is threaded a pipe, these pipelines are driven to vibration simultaneously.Therefore, under flox condition, on every circulation duct, deflection (promptly reversing) will be taken place by the part of coriolis force effect, and make its longshore current mobile direction of threading a pipe lead over another part of that coriolis force is acting on, circulation duct and move.The moment that the first that is threaded a pipe by the oblique oscillatory flow of coriolis force deflection passes through the predetermined point in the vibration route of circulation duct, and this time or phase relation between in a flash of the corresponding to predetermined point of the second portion of this pipeline by in that route is the function of mass velocity that flows through the fluid of circulation duct.This time difference can be with many kinds of sensors, comprise optical sensor (in United States Patent (USP) Re 31450, detailed description being arranged), electromagnetic speed sensor (in United States Patent (USP) 4422338 and 4491025 in detail introduce), or position or acceleration transducer (also being disclosed in United States Patent (USP) 4422338) are measured.The embodiment that a kind of parallel line double fluid that has the sensor that is used to measure the Best Times difference is threaded a pipe has been described in United States Patent (USP) 4491025.This embodiment provides a kind of Coriolis mass flowmeter structure, and it is to work according to a kind of tuning fork-shaped mode of describing in United States Patent (USP) Re 31450 (tuning fork-likemanner).In United States Patent (USP) Re 31450 and 4422338, and on the patent application PCT/US88/02360 that announced on the WO89/00679, occurred about with resultant motion sensor signal going through with the method and apparatus of quality measurement flow.

In above-mentioned flowmeter design, all sensors are placed on the symmetric position at the entrance and exit position that longshore current threads a pipe usually, and this can provide required sensitivity, so that all selection sensors can measure, and the precision that makes the mass rate that records is in ± 0.2%.

Utilize the one or more inventions in United States Patent (USP) Re 31450,4422338 and 4491025, made about 100,000 Coriolis mass flowmeters, these flowmeters are extensively utilized on market.Use in the commerce of these flowmeters, show in the experience more than 10 years of using multiple different fluid product to measure aspect the mass rate: generally speaking, the final user is satisfied to the sensitivity and the precision of flowmeter performance, but require to improve its total stability, comprise zero stability, can reduce the maintenance of factory like this, comprise the correction again of flowmeter these flowmeters.In general, the instability of flowmeter comes from its susceptibility to the transmission of the undesirable mechanical energy from external source to this flowmeter.These external force also can influence zero-bit (measured value when promptly the not having flow) stability of flowmeter.

Though above-mentioned commercial experience shows the problem of not having circulation duct generation wear-out failure in actual use basically,, in the life-span that the method in the source of utilization minimizing wear-out failure is improved pipeline gradually, this will be to go a step further.Similarly, provide a kind of pressure seal housing of sealing, can improve flowmeter objectionable impurities and pressure being arranged up to 1000 pounds/square inch even the applicability of higher high pressure operating position.Even an artificial situation of doing when the rated pressure that reaches and this housing of manufacturing balances each other, use the housing that to describe among the application, can make the rated pressure of flowmeter reach 300 pounds/square inch (are about 2 to 1/2 inches situation at the runner pipe external diameter) and 150 pounds/square inch (to situation of large scale runner pipe) at least.

The invention provides a kind of improved mass flowmeter, it can obviously improve whole stability, comprises the susceptibility and the raising zero stability that reduce external force, reduces the tolerance preferably of pressuredrop characteristic and fluid pressure.For according to one or more in above-mentioned all patents and Coriolis mass flowmeter that make has been done the improvement in many designs, its result makes their successful characteristics and operating feature be able to best the performance.

The present invention relates to Coriolis mass flowmeter, it comprises one or many circulation ducts, and these pipelines are energized, and vibrate with the resonant frequency at the circulation duct that contains the fluid that passes through therein.By a feedback system of describing in the past excitation frequency is maintained in this resonance, this feedback system monitoring is full of the variation of the resonance characteristics of the pipeline that fluid is arranged, and this variation is the result who changes the fluid mass variation that causes because of fluid density.The installation of the circulation duct of these Coriolis mass flowmeters makes it vibrate around a vibration axis that is positioned at mounting points or place, strut place substantially.The resonant frequency of vibration is relevant with the vibration axis.Circulation duct is also around one second axis deformation (reversing), is the coriolis force that response causes because of the fluid that flows through oscillatory flow and thread a pipe, and circulation duct centers on this second axis generation deflection or reverses.This root axis of mentioning later is relevant with the deflection that coriolis force causes, and it is transverse to the vibration axis basically.A kind of improved flowmeter provided by the invention, its stability is improved, and its susceptibility that external force is disturbed is also little, and its main cause is that the setting of sensor is able to optimization, and this will describe in detail in the back.Cause other of whole improved stability of improved flowmeter to improve, comprise the sensor that reduces four times at least and the quality of driver (the driver).

In a most preferred embodiment, a kind of improved U-shaped circulation duct structural design is provided, this structure has two straight substantially entrance and exit arms, they are assembled mutually at processing line concetrated pipe (Process line manifold), and, in two symmetric position bendings on duct length, this two bend is separated by a straight substantially pars intermedia branch.Also imagination is: some improved U-shaped circulation ducts will have the entrance and exit arm of convergence, they are separated by a continuous bend rather than straight pars intermedia branch, and other U-shaped pipelines then will have substantially parallel entrance and exit arm according to popular commercial embodiment.Be connected two motion sensors (motion sensor) with every circulation duct in symmetric position, its location of two will make for they monitorings and pass to the susceptibility of external force of the signal of flowmeter electronic section, obviously reduces than the susceptibility of the commercial mass flowmeter known to the past.In a most preferred embodiment, for realize this require special with sensor be located between but approach as far as possible to reverse node on every side of stream pipe of the pipeline of waveform (second out of phase twist mode) and the crooked waveform of the 3rd out of phase in second out of phase, and, driver is placed on apart from the equidistant part of these sensors.These motion sensors add the quality behind their support, and driver adds the quality behind its support, basically less than the quality of the appropriate section of commercial in the past mass flowmeter.Because the strut of the novelty of the adapter shape sleeve pipe with a novelty is provided, circulation duct has optionally been reduced the susceptibility of wear-out failure, above-mentioned strut is used to limit every circulation duct and produces the axis of vibration around it, but, also can be used alternatingly traditional strut, in some embodiments, omitted strut.In one embodiment, the U-shaped of utilize assembling is used for being connected with the processing line of monitoring so that flanged (FLGD) shape (wafer configuration) manifold structure not to be provided.The pressure sealed housing of one special sealing is provided, and this shell is circulation duct, all motion sensors, and driver and subsidiary electric connection contain.The invention discloses several embodiment of this housing, Fig. 8 wherein, the embodiment shown in 9 is the most desirable.

Fig. 1 represents by a kind of best Coriolis mass flowmeter of the present invention;

Figure 1A expresses according to the location situation of Fig. 1 embodiment being made all motion sensors after the model analysis;

Fig. 2 represents a kind of random novel pole structure;

Fig. 3 represents one by best Coriolis mass flowmeter of the present invention, and it has a sheet manifold structure, and this structure division is positioned at as shown in Figure 4 a housing;

Fig. 4 represents a random high pressure shell structure;

Fig. 5 A-7I represents shaking table (shaker table) stability test result;

Fig. 8 represents the High Pressure Shell structure that another is random, and this structure is being best aspect the convenience of funds spending and processing;

Fig. 9 provides the further details of relevant Fig. 8 shell structure; And

Figure 10 A to 11L is illustrated in the further test result that the back will be described to.

In main feature of the present invention, namely reduce external force to the impact of flowmeter stability, be that the optimal layout in a limited range is realized by all sensors and strut. We can find: be among 0 to 2000 He Zhi in frequency range, six kinds of vibrational waveforms are arranged basically, their excitation may cause the forfeiture of flowmeter stability. These six kinds of waveforms are: the crooked waveform of (1) (being lower than the low-frequency of driving frequency) first homophase; The crooked waveform of (2) first outs of phase, this waveform is corresponding to basic driving frequency; Except driving frequency is the intrinsic frequency of fluid-filled straight tube (and model analysis (mode analysis) is carried out with blank pipe); (3) first outs of phase are reversed (being also referred to as deflection or deflection) waveform; (4) second outs of phase are reversed waveform; The crooked waveform of (5) second outs of phase, and the crooked waveform of (6) the 3rd outs of phase. Realize the optimal layout of all sensors, to obtain by the model analysis of flowing pipe, at that pipe two node (node) are set according in six kinds of waveforms each, and according to the geometry, size and the material that flow pipe, determine that those are the most closely near the node of placing all sensors. For example, for the stream pipe of geometry as shown in Figure 1, model analysis shows: second out of phase that all sensors are placed on the either side of stream pipe is best reversed between node and the 3rd out of phase bending node, and each of as close as possible these node. Those skilled in the art can understand: according to other characteristics of geometry and stream pipe, can be arranged on each other for all node of six waveforms of enumerating and not exist together. In some stream tube shapes, in fact two or more node of different wave can overlap, and enable all sensors are located at the position of coincidence, improve thus the sensitivity of stream pipe. As an experience rule, the present invention includes a discovery, namely, for improving flowmeter stability, can be in each side of pipe with all sensor settings in as close as possible at least two node parts, each nodal point is the node of a different wave among above-mentioned all waveforms, the node of a different wave among the waveform of especially above-mentioned (3) and (6) expression. The present invention also comprises a discovery, that is, waveform (1), the i.e. impact of the crooked waveform of first homophase, can utilize the layout of strut to be reduced or eliminate, wherein the layout of strut with the harmonic wave of the harmonic wave of waveform (1) and waveform (2) separately.

Fig. 1 has represented to plant best improved U-shaped and motion sensor is located and the most preferred embodiment of the Coriolis mass flowmeter of installation.As commercial flowmeter now, circulation duct 112 firmly is installed on the point 131 of concetrated pipe (manifold) 130.Strut 122 firmly is installed on circulation duct 112, thereby when circulation duct 112 is encouraged by the tuning fork mode by driver 114, defines vibration axis B '.When stream material was flowed through pipeline 112, coriolis force (Coriolis force) made pipeline around deflection axis A ' deflection.As shown in the figure, respectively from driver 114, motion sensor 118 and 116 electrical cnnector 125,126 and 127 are connected and are supported on the carriage 128, and make (producing during connection) stress minimum and stablize; Perhaps, adopt another kind of method, adopt the printed circuit board (PCB) that is fixed on the housing without carriage (will discuss) as the back.Connector shown in Fig. 1 is single line or has the banded flexible connector of sunkening cord that they are according to the stable semi-circular installation of little stress.Imagination can be used flexible coupling, this series number in application on May 22nd, 1986 is 865,715 U.S. Patent application (now abandoning), and renewal application (series number 272209, application on November 17th, 1988, abandon) and its renewal application (series number in 10,337324,1989 on July please) etc. in described.This flexible connector also has stable and a semi-ring shape that stress reduces.Among Fig. 1, all trial movement sensors 116 are positioned at the end of inlet or outlet stool (leg) 117, and proper position before bend.All motion sensors 118 are positioned at the position of being determined by model analysis according to the present invention, have reduced the influence of external force so effectively.In a commercial flowmeter embodiment, have only movable sensor 118, test all movable sensors 116 that are used for the comparison purpose and cancelled.The flowmeter of Fig. 1 comprises the housing 140 that contains circulation duct and relevant annex thereof, and this housing has been fixed concetrated pipe 130 again, still, preferably can use as Fig. 4 or the shown in Figure 8 and following flowmeter shell that will describe.

The flowmeter of Fig. 1 embodiment can reduce the effect of external force, and another characteristics of its structure comprise that circulation duct and their annex balance each other, and uses sensor and the exciter assembly that reduces quality.

In Coriolis mass flowmeter, all circulation ducts are as spring, and its elastic force mainly acts on the entrance and exit arm.All circulation ducts of Fig. 1 embodiment are improved U-shapeds, the permanent strain that it does not cause because of bending in the entrance and exit arm.Do not have bending in process, making in four zones does not have permanent strain, and in the twin flue flowmeter, elastic force works in these four zones.Its result, if used the similar material of basic identical size, all four zones demonstrate the identical reflection to elastic force basically.So just improved the ability that flow meter manufacturers goes equiulbrium flow to thread a pipe.When the magnet and the coil that use than lightweight, and reduce the size of their bearing, then can reduce the quality of all motion sensors and driver, like this, can further improve the balance of circulation duct.

As existing commercial flowmeter, all motion sensors and driver comprise a magnet and a coil.All sensors are the sensor of disclosed the sort of type in the United States Patent (USP) 4422338, and their rectilinearity are followed the tracks of the whole motion in the pipe whip route.In Fig. 1 embodiment of the present invention and other embodiment, the general assembly (TW) of these sensors and driver has reduced at least about four times compared with their general assembly (TW) among all existing commercial flowmeter embodiment, has preferably lacked five to six times or more.When using one to have the light weight bobbin winder bracket of mold pin joint, and wound coil is arranged No. 50, and continue to use the magnet of equal in quality, then can alleviate quality.All light amount sensors and driver are directly installed on all circulation ducts, can remove analog bracket from like this.For example have one with Fig. 1 embodiment in the identical embodiment of size and dimension, external diameter of its stream pipe (flowtube) is about 0.25 inch, wherein the quality of the light weight coil of Cai Yonging is about 300 milligrams.Coil before some, be used for size suitable, make and have in all mass flowmeters of substantially the same stream external diameter of pipe size according to United States Patent (USP) Re 31450,4422338 and 4491025, their quality is about 963 milligrams.In the flowmeter embodiment according to the same size of Fig. 1, mass flowmeter has increased the new subassemblies (1 exciter coil and 2 cell windings, each is heavy 300 milligrams, and 3 blocks of magnet, every heavy 1 gram) that gross weight is about 3.9 grams.Contrast is got up, and in the commercial embodiment before comparing, mass flowmeter has increased the corresponding assembly (1 driver circle, 2 cell windings, 1 coil bracket, 1 magnet carrier and 3 magnet) of 22.2 grams.

For the embodiment of Fig. 1, once carried out representational model analysis.According to the result who analyzes, have on the circulation duct of size shown in following table 1 and Figure 1A and character one, second out of phase can be reversed the node of waveform and the node of the crooked waveform of the 3rd out of phase and be located.

Table 1

Pipeline material: 316L stainless steel

Duct length: 16 inches

Outer diameter tube: 0.25 inch

Pipeline wall thickness: 0.010 inch

Inlet arm: 3 inches

Outlet stool: 3 inches

Middle pipeline section: 5 inches

Sweep radius: 1.25 inches

In the position of the final sensor of the centre of aforementioned all waveform node, be positioned on the position that the horizontal axis that extends from the center of radius of sweep folds 22.5 °.

The position of the sensor that this is final and levels off to each of two node in each side of pipeline not only between two node as far as possible.Intelligible as those skilled in the art, utilization is to having other precise shape, all circulation ducts of size and material are done model analysis, just can determine the position of each node of all above-mentioned all waveforms, and make position definite very fast optimised of final sensor.

In some embodiment of improved flowmeter of the present invention, with respect to the existing commercial flowmeter of making by the application assignee that supply is arranged, basic excitation frequency (the crooked waveform of first out of phase) is improved, thereby has improved its harmonic wave numerical value.Impel like this about single humorous wave energy and other Harmonic Waves of excitation waveform and separate preferably.For example, in having Fig. 1 embodiment of above-mentioned size, be lower than the frequency situation of 2000 He Zhi, the tuning function of other five kinds of interested waveforms, each and tuning at least 20 He Zhi that separate of excitation frequency for all.

In the embodiment in figure 1, the effect of strut layout is that the first same-phase corner frequency and basic excitation frequency are separated, avoid thus may with the incentive action of the first same-phase corner frequency.With all the other four kinds interested waveform correspondent frequency on the effect of the external force of working partly reduced owing to have the circulation duct structure of balance.In addition, in this embodiment, with all motion sensors be placed between but very be close to position between these two kinds of all node of waveform, these node are close to each other just, like this, can reduce the effect that second out of phase is reversed waveform and the crooked waveform of the 3rd out of phase.Can imagine: consider its size by model analysis, shape and material like this, can be selected other location, with the effect of the waveform that reduces those stability that influence any particular conduit most.

Changing hydrodynamic pressure under condition less than 10 pounds/square inch to about 1000 pounds/flat upright inch, Fig. 1 embodiment of the existing commercial Coriolis mass flowmeter of making to the existing commercial D type flowmeter made by the application assignee with by other people tests, the result shows: when pressure is tending towards 100 pounds/square inch, variation has taken place in excitation frequency and torsion frequency, and this precision to quality flow measurement produces bad influence.So far, can conclude: increase approximately 20% when flowing thickness of pipe, and will flow the pipe component package in the insensitive housing of a custom-designed fluid pressure, just can reduce the effect (this will set forth below) of high fluid pressure.

For example, having external diameter with one is that pipe thickness among 0.230 inch the flowmeter embodiment shown in Figure 1 of stream pipe increases, and is increased to about 0.012 inch from about 0.010 inch, with the instability that reduces to cause because of high fluid pressure.

Fig. 2 represents one according to random pole structure of the present invention.With a slice metal (as 316L or 304L stainless steel) or other suitable material punching press and form every strut 122, make it have two and have from hole (hole 124) to the sleeve of macropore 120 papilliferous transition portions 121 with circulation duct external diameter.But these strut brazings or be welded on all circulation ducts are concentrated around the stress that it produces the main position of vibration to reduce connecting portion 123 places and pipeline.Yet, utilize the traditional strut that disclosed in the past in the prior art, do not leave the scope of the invention yet.

Fig. 3 represents the Coriolis flowmeter as Fig. 1 an of the best, has the exploded view of production line attaching process.Replace typical flanged (FLGD) concetrated pipe in the prior art, the spy provides the tabular of a novelty can't blue structural member 230, its end 232 can be in manufacturing process line or other commercial processing line, by passing flange hole 238 and being bolted between the two ready-made flanges by the whorl brace rod 234 of nut 235 fix in position.

Fig. 4 show a kind of form housing, it can reduce the pressure effect.This version can be used for containing whole circulation duct and sensor link.It comprises the enough big pipe of a diameter 350, to contain all circulation ducts 312, driver, motion sensor and relevant wire connecting part (not shown) thereof.This pipe is curved the shape of circulation duct.Then, this pipe vertically is cut into the two halves that equate basically along it, again with the relevant driver of circulation duct 312 companions, motion sensor and wiring are packed into wherein in half pipe together, second half tube cover installs on the combinations thereof part, and along two longitudinal slots their seam are got up, in the joint they are soldered on the concetrated pipe again.Like this, just made a pressure sealed housing, it is applicable to the use occasion that contains harmful fluid, and is able to take at least 300 pounds/square inches of high pressures until the order of magnitude of 500 pounds/square inch even higher value.For some embodiment, an available printed circuit board (PCB) is connected in the inside of housing, receives on the circuit board from driver and all motion sensors with flexible connector again.One junction box is connected in housing again, is connected in circuit board by electric wire, and electric wire can pass the sealing joint of case top.The junction box is connected with the device of electronic processing from the signal of sensor again, providing the mass rate reading, and can read the fluid density reading when needing.

The another kind of housing of being convenient to housing processing is shown in Fig. 8, and wherein a segment table is shown in Fig. 9.The housing of this shape is to make with other part of mold pressing steel plate of all semicircle cross sections, sees (only having represented the plate 2 or 4 among Fig. 8) shown in Figure 9, and these steel plateelements weld the back mutually and form housing.When specifically being used for the embodiment situation of Fig. 1, this housing is made up of ten parts in addition that indicate the 1-10 printed words as shown in Figure 8, and these ten other parts combine in following mode:

Five parts (label is 1,2,3,4 and 5 among Fig. 8) are formed half of housing, promptly cover half outer peripheral face of stream pipe when combination, and these five other parts are welded on the support that comprises the entrance and exit Ji Kou pipe that flows pipe.Printed circuit board (PCB) (all not expressing in arbitrary figure) is fixed on the housing and is positioned at as far as possible near the pick-up winding (pick-off coil) that flows all sensors on pipe position partly, and the pick-up winding terminals rely on the electric wire that contains bend of type above-mentioned or independent semi-circular electric wire to be connected with these printed circuit board (PCB)s.Then, electric wire is delivered to the central straight section (i.e. section 3, it has contained the straight circulation duct pipeline section 12 of Fig. 1) of housing along housing, is provided with wiring feedthrough for flowmeter electronic device at this.This feedthrough (Fig. 8,9 do not express) comprises all posts of all electric wires of direct connection, maybe can comprise the 3rd printed circuit board (PCB) that connects all electric wires, and this plate is connected in the feedthrough post, receives the junction box (not shown) of section on 3 that is positioned at the interlude of housing again.After wiring is finished, 5 of all the other of housing in addition parts (do not express among Fig. 8, this figure is the vertical view of housing) side by side be soldered to support and front said combination with part seam on, the most handy automatic weldering during welding.These back five other parts are formed another half of housing.Weld seam between these other parts is shown in the heavy line among Fig. 8.In addition, all welding are along the weldering of the suture (not shown) of the internal and external circumferential of housing, and these two weld seams are inside and outside at the outer cover of being made up of stream pipe and support respectively, and the halves of the top of housing and bottom is linked to each other.

A housing embodiment presentation graphs 4 and 8 two kind, those of ordinary skill in the art understand: be easy to make similar housing, to be applicable to any size and crooked shape or straight tube shape Coriolis mass flowmeter, and, according to related accurate shape, mold pressing (abnormal shape) the steel semi-circumference that other number can be advantageously selected in the making of Fig. 8 and 9 embodiment is part in addition.As clearlying show, only otherwise break away from ultimate principle of the present invention, those skilled in the art that are easy to design other wiring topology.

Shaketalle test is to be used for test to thread a pipe and during relevant annex extraneous vibration power and operating line The noise at oscillatory flow.Between the shop equipment on-stream period, this external force is often to occur.Fig. 5 A to 5F has represented with the test findings of shaking table to a kind of D25 of Mi-croMotion incorporated company type Coriolis mass flowmeter of existing commercialization.Fig. 6 A to 6F is the test result to a kind of similar test of the Micro Motion D40 of incorporated company type flowmeter of existing commercialization.The internal diameter of the circulation duct of D25 type is 0.172 inch, the D40 type be 0.230 inch.Fig. 7 A to 7I is the experiment test result of similar test that the sort of Coriolis mass flowmeter that is similar to Fig. 1 flowmeter is done.

Among each figure in Fig. 5 A to 7I, X-axis is the axis (promptly being parallel to vibration axis B '-B ') by meter flanges, and Y-axis is the plane (promptly being parallel to distortion axis A '-A ') that is parallel to all circulation ducts place.The Z axle is perpendicular to the plane at all circulation ducts place.All tests have related parameter to be summarized in the table 2:

Table 2 figure number full scale vertical scale electronic section vertical scale accounts for full motion

The number percent axis of the output scale of flow frequency sweeping

(1bm/ minute) be (milliampere) (%) 5A 1.04 4.20 10 Z5B 10.4 4.20 100 Z5C-15-2000--Z5D 1.04 4.20 10 X5E 10.4 4.20 100 X5F-15-2000--X6A 1.04 4.20 10 Z6B 10.4 4.20 100 Z6C-15-2000--Z6D 1.04 4.20 10 X6E 10.4 4.20 100 X6F-15-2000--X7A 1.04 4.20 10 X7B 10.4 4.20 100 X7C-15-2000--X7D 1.04 4.20 10 Z7E 10.4 4.20 100 Z7F-15-2000--Z7G 1.04 4.20 10 Y7H 10.4 4.20 100 Y7I-15-2000--Y (He Zhi)

These shaketalle tests are that the complete mass flowmeter with housing is not carried out.Be illustrated in the output on the bar chart recording chart of Fig. 5 A to 7I, be in response to the reading of the motion sensor of corresponding external vibration.The order of representing in every picture group table be flowmeter for linear frequency ramp (ramp) (scope is from 15 He Zhi to 2 kilo hertzs), and the response of the inputted vibration on random frequency after this (see Fig. 5 C, 5F, 6C, 7C, 7F, 7I).Frequency slope was created in 10 minute time period, and random vibration resulted from about 5 minute time period.Fig. 5 A, 5B, 5D, 5E, 6A and 6B, the influence of the external vibration of the various frequencies when its each figure is illustrated in six kinds of Harmonic Waves of excitation D25 of above-mentioned discussion and the motion of D40 type flowmeter.

Fig. 7 A to 7F expresses for by the flowmeter shown in Fig. 1 embodiment of the present invention, the susceptibility situation of the excitation that causes around the external vibration of X and Z axle (identical) with the axis among Fig. 5 A and the 5F, and the scale of each figure is identical.Fig. 7 G to 7I draws according to Y-axis.(random vibration at first produces in Fig. 7 D-7F).Need know: the flowrate optimization meter shows when six kinds of Harmonic Waves of stimulus movement, can reduce the influence of external vibration significantly.Like this, optimum structure design is expressed flowmeter and the external force effect is isolated effectively.

In addition, test to measure the influence of external vibration zero stability.This test provides (Δ t) measurement stability of the mistiming when no flow, promptly is called the result of (jitter) test of beating.One frequency counter is used for averaging or the direct before pulse width of measuring add subtract counter of filtering to electronics (signal).Test is to carry out along the input of the random frequency in the acceleration range on X, Y and the Z direction in utilization on the shaking table.The result shows: for D25 and D40 type flowmeter, along with the raising of acceleration, the influence of external vibration causes pulse width to disperse (expansion) at double or several fold from average bit.For every axis, such dispersing at the optimal flow rate meter obviously reduced.Like this, as the vibration test situation, the test of beating shows: optimal flow rate meter structural design is kept apart flowmeter the influence of outer acting force effectively.

Figure 10 A-10G is comprised, and is the chart of using the further data that obtain by the flowmeter embodiment just like the structural design of Fig. 1 to describe.Disclosed as me, this flowmeter has a traditional strut and a stream pipe than the stream thickness of pipe 20% of the existing commercial flowmeter of suitable size, according to requirement of the present invention, in the test used all sensors place between and all node of as close as possible above-mentioned waveform (4) and (5) between the position.In when test, the stream pipe of this flowmeter embodiment is by a Fig. 8, and the housing of 9 shown types covers half (being half of circumference of pipe), in the outside of housing attaching one junction box (not expressing among the figure) is arranged, and electric wire passes housing and delivers to this junction box.The junction box is connected in another chest (being called " remote control flow transmitter " or " RFT ") by custom, and this chest includes the flowmeter electronic section, and has the reading plate of mass rate and density value, and from then on chest can be collected the data among Figure 10 A-10D.About 0.206 inch of the internal diameter of the stream tube wall of this flowmeter embodiment.

Each expression of Figure 10 A and 10B utilizes mass rate to test the calibration curve between precision and the flow for the water of 0-45 ppm.The difference of Figure 10 A and Figure 10 B is: Figure 10 A represents is to be " 22 point " calibration curve of all point-renderings of beginning to record under (3-4) ppm situation approximately with mass rate; Figure 10 B is " 45 a point " calibration curve, has wherein collected the data point that more data point, especially mass rate are lower than 5 ppm (from about 0.5 ppm flow) situation.

Figure 10 B has represented that also mass rate is 0 fluid line pressure drop data during to about 45 ppm.After combining, Figure 10 A and 10B show: within accuracy value ± 0.2% of announcing, flowmeter embodiment's of the present invention is all right, the assignee that above-mentioned this accuracy value scope is the applicant, the i.e. characteristic index of the existing commercial flowmeter of Micro Motion incorporated company.Figure 10 B has showed that also this flowmeter embodiment has approved fluid line pressure and falls performance.

Figure 10 C and 10D are respectively the simulation migration values of mass rate and density, for 0 chart to the hydrodynamic pressure of about 2000 pounds of/square inch hydraulic pressure.Every kind of situation, on the average empirical standard deviation value curve that records for the commercial mass flowmeter of selling by Micro Motion incorporated company of D series, a contrast curve is arranged.In Figure 10 C, each data point of flow simulation skew and flow standard difference is with " second " unit representation.In Figure 10 D, density simulation migration and density criterion deviation are then used " gram/cubic centimetre " unit representation.In these two kinds of situations, all data show: in the standard deviation data that records, and flowmeter of the present invention functional.

Figure 10 E, 10F and 10G be with Fig. 5 A to 7I in data obtain similar method, the chart of the shaking table test data that obtains, but be expressed as the curve of shaking table frequency (He Zhi), and Fig. 5 A to 7I is with the reproduction product of shaking table frequency (He Zhi) to the rectangular chart of motion sensor reading (second) to simulation output (being mass rate) upset (second).In addition, Figure 10 E, the data among Figure 10 F and the 10G are to collect on the flow meter part with half shell annex, the used flow meter part of this subassembly and Figure 10 A-10D data is identical.For comparison purpose, two kinds of similar curves that all do not have the different D25 type flow-path tube duct device of housing annex in Figure 11 A-11L, have also been represented.In each case, X, Y and z axis are by the above-mentioned definition of having made, and shaking table vertical scale frequency sweeping is from 15 to 200 He Zhi, and the span of remote control frequency forwarder is 5 Grams Per Seconds, and its correction factor is 1, can obtain simulation output from this forwarder and read certificate.Other has related parameter to be summarized in table 3:

Table 3

The telecontrol equipment of figure number shaking table

Scan axis

10E log X embodiments of the invention

10F log Y embodiments of the invention

10G log Z embodiments of the invention

The X D25 type device 1 of 11A linearity

11B log X D25 type device 1

The Y D25 type device 1 of 11C linearity

11D log Y D25 type device 1

The Z D25 type device 1 of 11E linearity

11F log Z D25 type device 1

The X D25 type device 2 of 11G linearity

11H log X D25 type device 2

The Y D25 type device 2 of 11I linearity

11J log Y D25 type device 2

The Y D25 type device 2 of 11K linearity

11L log Y D25 type device 2

The linear sweep of shaking table used time when moving through per 100 He Zhi vibration interval is identical, that is, for example used time of the time of 15 to 115 He Zhi scanning and for example from 1000 to 1100 He Zhi is identical.In log scanning, in low frequency such as 15-400 He Zhi situation, the time interval of consumption has lengthened, and the time interval of consuming under high frequency situations has then shortened (or acceleration).Can see that log scan is clearly pointed out some frequencies, in those frequencies, in existing commercial D type flowmeter, external drive causes the harmonic wave upset.Figure 10 E, 10F and 10G show the susceptibility of flowmeter of the present invention to this influence, is significantly less than the D25 circulation duct.

Although express the most preferred embodiment of compound circulation duct mass flowmeter, can imagine: invention as herein described also can be implemented with a kind of Coriolis mass flowmeter, this kind flowmeter has only a circulation duct, it or be connected in a member such as leaf spring or one illusory (dummy) pipeline, forming a tuning fork, or when single circulation duct quality is very little, it is installed on one and has on the base of big quality with circulation duct.

Though top discussion is concentrated on above the size and dimension of circulation duct for giving an example purpose, for being familiar with those of ordinary skill in the art, can in actual enforcement of the present invention as herein described, make many changes and improvements fully, and make this changes and improvements not leave the scope of the present invention that limits by following claim.

Claims (11)

1. mass flowmeter, wherein the mass flow rate of stream material is to determine according to a kind of effect of the coriolis force that records.Described flowmeter comprises: at least one continuous flow pipeline, and its unmatchful pressure-sensitive joint or pipeline section, described pipeline firmly is installed on described bracing or strutting arrangement with the inlet end and the endpiece of described pipeline; One second member, it is parallel in the plane of described circulation duct one and firmly is installed on described bracing or strutting arrangement, thus described member and described pipeline shake in a tuning fork mode; Exciting bank, be used to make described pipeline and member around with each described firm contiguous axis of bending concussion of bracing or strutting arrangement; The pair of sensors device, it is installed on the described pipeline at all opposite sides of described exciting bank, with monitor described pipeline vibratory movement, comprise the motion that the coriolis force of described pipeline under flow state causes; And signal processing apparatus, it is surveyed from the signal of described sensor and with this signal transition is mass flow value, it is characterized in that, each sensor device mounting points is close to two immediate node of a pair of vibrational waveform of described pipeline as far as possible, described a pair of vibrational waveform is to do a ripple attitude at (i) to analyze to determine all node of each waveform, and (ii) select on the basis of two waveforms with the most approaching each other node, then at the crooked waveform of first same-phase, the crooked waveform of first out of phase, first out of phase is reversed waveform, second out of phase is reversed waveform, the crooked waveform of second out of phase, or choose in the crooked waveform of the 3rd out of phase.

2. mass flowmeter as claimed in claim 1 is characterized in that, described second member is second identical with described first a pipeline basically continuous flow pipeline.

3. mass flowmeter as claimed in claim 1 or 2, it is characterized in that, every described continuous circulation duct has a straight substantially straight substantially outlet stool of inlet arm and, they are focused on the described bracing or strutting arrangement toward each other, and interconnect with respect to described bracing or strutting arrangement by the remainder of all described continuous conduits.

4. mass flowmeter as claimed in claim 3, it is characterized in that, described inlet arm and outlet stool interconnect with respect to support by a straight basically part of described pipeline, and this straight substantially part is in arbitrary end bending, to meet at each straight substantially tube portion.

5. mass flowmeter as claimed in claim 1, it is characterized in that, the set-point of described sensor device at the entrance side and the outlet side of described circulation duct, is close to corresponding all node that second out of phase is reversed waveform and the crooked waveform of the 3rd out of phase as far as possible.

6. mass flowmeter as claimed in claim 2, it is characterized in that, the set-point of described sensor device is at the corresponding entrance side and the outlet side of every circulation duct, although be close to corresponding all node that second out of phase is reversed waveform and the crooked waveform of the 3rd out of phase.

7. mass flowmeter as claimed in claim 2, it has all described circulation ducts, these pipelines are clamped in together by strut, and some is put along the entrance and exit arm, determine the position of all described points according to model analysis, these points can make between all frequencies of crooked waveform of first same-phase of all described circulation ducts and the crooked waveform of first out of phase separately, enable separately the influence of the crooked waveform convection current of first same-phase amount meter sensitivity to be reduced to minimum by harmonic wave.

8. mass flowmeter as claimed in claim 7, it is characterized in that, all described continuous flow pipelines have a straight basically straight basically outlet stool of inlet arm and, this relatively is focused at their ripples on the described bracing or strutting arrangement, and interconnects with respect to bracing or strutting arrangement by the remainder of all described continuous conduits.

9. mass flowmeter as claimed in claim 7 is characterized in that, all described struts comprise papilliferous fixed muffle device.

10. mass flowmeter as claimed in claim 2, it is characterized in that bracing or strutting arrangement comprises a non-flanged entrance and exit supercharging device, this pumping chamber comprises two circulation chambers that separate, one of them chamber is used for making fluid separation at entrance side, and another is used for making fluid synthetic again at outlet side.

11. mass flowmeter as claimed in claim 1 or 2, it is characterized in that, it also comprises a geometric configuration and the essentially identical pressure-tight housing of described circulation duct, and it contains all described pipelines, described sensor device and described driver, and is welded on the described bracing or strutting arrangement.

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