WO1995011426A1 - Ultraschalldurchflussmesser - Google Patents
Ultraschalldurchflussmesser Download PDFInfo
- Publication number
- WO1995011426A1 WO1995011426A1 PCT/EP1994/003372 EP9403372W WO9511426A1 WO 1995011426 A1 WO1995011426 A1 WO 1995011426A1 EP 9403372 W EP9403372 W EP 9403372W WO 9511426 A1 WO9511426 A1 WO 9511426A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- ultrasonic
- flow
- measuring
- flow meter
- quality
- Prior art date
Links
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
- G01F1/667—Arrangements of transducers for ultrasonic flowmeters; Circuits for operating ultrasonic flowmeters
-
- 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
Definitions
- the invention relates to an ultrasonic flow meter according to the preamble of claim 1.
- Vane meters are widely used in flow measurement technology, particularly when determining very small quantities. Your advantage lies in the compact design and simple construction.
- the devices are inexpensive to manufacture and, thanks to the low electronic complexity, are able to work independently of the network.
- the impeller rotation is usually scanned inductively, capacitively or with ultrasound.
- a disadvantage of these devices is the contamination of the impeller bearings.
- the magnetic-inductive process requires an electrically conductive liquid. These devices are expensive because of their relatively complex structure. Battery operation is possible due to the generation of the necessary strong magnetic alternating field kav.
- Vortex meters require an undisturbed turbulent flow with long inlet sections. They are only suitable for measuring purposes when there are high flow velocities. Coriolis mass flow measuring systems are usually very maneuverable and therefore expensive. External vibrations can have a sensitive effect on the function of the device.
- the non-resonant ultrasound procedures have the following parts.
- the lower measuring limit (sensitivity, resolving power) is essentially determined by the length of the measuring section in the direction of flow. Adequate accuracy therefore requires long measuring distances in the pulse method. Other continuously measuring ultrasonic methods, which evaluate phase or frequency differences, also require a long measuring distance (because of the low quality of the measuring cell).
- a complex construction of the measuring tube is necessary, e.g. B. by special reflectors which are attached in the measuring tube to deflect the ultrasonic wave in the desired manner.
- the necessary thermal stability of the measuring cell with regard to the acquisition of measured values requires a great deal of effort in the structural design.
- the object of the invention is to design an ultrasonic flow meter so that even small volume flows with a small measuring volume can be detected precisely.
- the resonance technology with high quality of the measuring cell enables significantly shorter measuring distances while simultaneously increasing the sensitivity and the resolution of the measuring system, smaller dimensions of the measuring cell overall, multiple reflections are not necessary,
- the measuring cell is cheaper to manufacture.
- FIG. 1 shows a schematic ultrasonic transducer.
- Figures 2 and 3 show two flow measuring arrangements.
- FIGS. 4 and 5 show spectra of a resonator and
- FIGS. 6 and 7 block diagrams of the electronic signal processing for two ultrasonic flow meters.
- FIGS. 8 to 11 show schematic embodiments in which the ultrasound transducers are embedded in materials with low sound resistance and in which the flow channel tapers towards the center.
- FIG. 1 schematically shows a modified ultrasonic transducer 1.
- the structure differs from known designs in that an additional damping layer 4 with special acoustic properties is applied to the front of the piezo oscillator 2.
- a transition layer 3 ensures the acoustic adaptation of the piezo and the damping layer.
- the piezo oscillators 2 are damped by a damping body 5 on the rear in order to achieve a larger bandwidth of the oscillator. This is known for so-called pulse converters in ultrasonic material testing.
- FIG. 2 The basic structure of an ultrasound flow meter is shown in FIG. 2.
- Two ultrasound transducers 2 are arranged with parallel front sides in such a way that a resonance chamber 8 is created between them, through which the liquid medium flows, the resonance chamber 8 being a part of the flow mungskanal 7 forms.
- the resonator length should not be greater than 40 wavelengths of the ultrasound used for the measurement. With resonator lengths of ⁇ 20 wavelength units, together with resonator qualities between 20 and 200, optimal results can be achieved.
- 3 shows the basic structure of a further ultrasonic flow meter.
- Two further ultrasound transducers 1 are arranged with mutually parallel front sides in such a way that a resonance space 8 that is as identical as possible is created between them as in the two other ultrasound transducers, the amounts of the angles between the flow direction and each of the resonator axes being the same.
- the ultrasound transducers transmitters
- superimpositions of the returning and returning sound wave occur in the fluid ("medium”). They are largely independent of the characteristics of the sound source and are essentially determined by the geometry of the resonator and the sound characteristics of the medium (density, speed of sound).
- the acoustic signals are detected on the opposite ultrasound transducer (receiver).
- the material and the thickness of the damping layer have a decisive influence on the characteristics of the resonance curves (damping, bandwidth, coupling, etc.); they can be adapted to the respective requirements of the measuring task.
- the ratio of the sound width: levels of damping layer [Z (s)] and flowing medium [Z (w)] is important.
- the sensitivity and the resolving power of the measuring arrangement are determined by the quality of the resonator: sharp resonances are sensitive to minor detuning.
- materials such as glass, aluminum or Ke- ceramic for the damping layer.
- Stainless steel, copper, aluminum oxide, platinum or tungsten are preferably used for medium to high grades (100-1000).
- Stainless steel is particularly suitable for the implementation of the damping layer, since grades of 200-400, with water as the fluid, can be achieved.
- the thickness of the damping layer and the transition layer must be selected to be less than 1/8, since otherwise undesired resonances are generated in these layers.
- 1 means the ultrasonic wavelength.
- the acoustic impedance of the transition layer 3 lies between that of the measuring medium and that of the damping layer 4.
- the transition layer consists of epoxy resin.
- the layer thickness is 100 ⁇ m.
- the damping layer 4 consists of copper.
- the layer thickness is 80 ⁇ m.
- FIG. 5 A section of the spectrum from FIG. 4 is shown enlarged in FIG. 5.
- the distance between two resonances shown here becomes smaller the longer the resonator length.
- the carry-along effect is used in the ultrasonic transit time method, i. H. , the running time of the sound wave is changed by the flowing medium.
- a distinction is essentially made between two operating modes, pulse operation or continuous operation.
- the measuring arrangement is operated with a sinusoidal signal and adjusted to a resonance frequency.
- the change in the transit time of the ultrasound signal caused by the change in the flow velocity of the medium causes a detuning of the resonator, which is to be measured at the receiver as a phase shift (phase measurement).
- the frequency shift is a measure of the flow velocity.
- the present method for determining the flow rate uses the frequency shifts of a fixed measuring section (path length control loop, la bda locked loop, LLL) resulting from the entrainment effect.
- each is regulated to a frequency at which resonance occurs, that is to say a whole multiple of the sound wave length 1/2 between the transmitter and receiver.
- the difference between the resonance frequencies f ⁇ and f 2 of the shaft with the speed components in or against the flow direction is either determined by switching the transmission direction or generated directly in two-track operation.
- the flow velocity v can then be calculated according to equation 1 and the desired volume flow V according to equation 2.
- V A * v * K Eq. (2)
- A pipe cross-sectional area
- K calibration factor
- the frequency shift of the resonance curve is evaluated using the LLL method.
- PLL phase locked loop
- FIG. 6 shows the block diagram of the electronic signal processing for one-way operation with two sensors (US1, US2).
- the switches Sl and S2 switch the transmission direction.
- the receiver signal is amplified and fed to a PLL.
- the PLL has the task of regulating a frequency at which resonance occurs. After half the measuring time, the sensors are switched.
- the respective frequency measurement is carried out with a counter module, so that after a measurement period at the counter output the difference frequency f - fi is available as a digital word.
- FIG. 7 shows the signal processing for two-line operation.
- the structure of the electronics essentially differs from the above-mentioned embodiment in that the switchover is omitted and each sensor pair is followed by a complete signal processing.
- the frequencies generated by PLL1 and PLL2 are processed simultaneously using mixer M.
- the desired differential frequency f 2 -fi is available at the mixer output for further processing and evaluation.
- Fig. 8 shows a flow meter in which the housing of the flow sensor consists of embedding material 9 with low sound resistance (less than 5 * 10 6 kg / m 2 * s) and good damping properties.
- the flow channel 7 narrows conically from both sides towards the center. Due to the narrowed cross section, it is possible to increase the flow velocity and thus the measuring effect. If the inlet and outlet sections are dimensioned correctly, the Flow rate increased several times, the pressure drop across the arrangement can be kept small.
- FIG. 9 shows the same arrangement as FIG. 8, but the embedding material 9 is surrounded by a metal tube 13. This provides better stability.
- the lining of the resonance chamber 8 with the embedding material 9 serves to acoustically dampen disturbing sound waves which arise in the metallic housing.
- Materials whose sound resistance is between 1.5 and 5 * 10 6 kg / m 2 s and have good damping properties can be used as the material.
- hard and soft rubber, polyurethane and various plastics are suitable.
- the ultrasonic transducers 1 are surrounded by embedding material 9.
- the rest of the tube can also be made of metal or another material with high sound resistance.
- the dead spaces 12 between ultrasonic transducers 1 and flow channel 7 are closed off from the flow channel 7 with a film 11.
- the dead spaces 12 are filled with liquid. You can also be connected to the flow channel via compensation channels 11.
- the sound resistance of the film 11 should be as close as possible to that of the medium.
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- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Fluid Mechanics (AREA)
- General Physics & Mathematics (AREA)
- Measuring Volume Flow (AREA)
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SK447-96A SK44796A3 (en) | 1993-10-16 | 1994-10-13 | Ultrasonic flowmeter |
EP94930948A EP0706640A1 (de) | 1993-10-16 | 1994-10-13 | Ultraschalldurchflussmesser |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DEP4335394.0 | 1993-10-16 | ||
DE19934335394 DE4335394C2 (de) | 1993-10-16 | 1993-10-16 | Ultraschalldurchflußmesser |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1995011426A1 true WO1995011426A1 (de) | 1995-04-27 |
Family
ID=6500363
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/EP1994/003372 WO1995011426A1 (de) | 1993-10-16 | 1994-10-13 | Ultraschalldurchflussmesser |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP0706640A1 (de) |
CZ (1) | CZ92496A3 (de) |
DE (1) | DE4335394C2 (de) |
HU (1) | HUT73914A (de) |
SK (1) | SK44796A3 (de) |
WO (1) | WO1995011426A1 (de) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE19648784A1 (de) * | 1996-05-28 | 1997-12-04 | Krohne Ag | Ultraschall-Durchflußmesser |
EP0945712A1 (de) * | 1998-03-25 | 1999-09-29 | Siemens-Elema AB | Vorrichtung zum Messen eines Gasflusses |
DE102006026311A1 (de) * | 2006-06-02 | 2007-12-06 | Endress + Hauser Flowtec Ag | In-Line-Meßgerät mit einem innen mit Polyurethan ausgekleidetem Meßrohr und Verfahren zu dessen Herstellung |
US7523675B2 (en) | 2006-06-02 | 2009-04-28 | Endress + Hauser Flowtec Ag | In-line measuring device with measuring tube lined internally with polyurethane and method for manufacture thereof |
Families Citing this family (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB9607804D0 (en) * | 1996-04-13 | 1996-06-19 | F T Tech Ltd | Anemometer |
DE10034474C1 (de) * | 2000-07-15 | 2001-10-11 | Flexim Flexible Industriemeste | Verfahren und Vorrichtung zur Charakterisierung eines Fluides oder Gases mittels Ultraschall |
DE10137193B4 (de) * | 2001-07-31 | 2004-02-05 | Sensotech Gmbh | Verfahren und Einrichtung zum Messen akustischer Größen in flüssigen Medien |
DE102004027546B4 (de) * | 2004-06-04 | 2006-10-05 | Fachhochschule Kiel | Verfahren und Vorrichtung zur Messung der Fließgeschwindigkeit in Volumina einer akustischen Resonatoranordnung |
DE102004027544B4 (de) * | 2004-06-04 | 2007-02-01 | Fachhochschule Kiel | Verfahren und Vorrichtung zur Bestimmung der Fließgeschwindigkeit in einem akustisch gut übertragenden Medium |
FR2906609B1 (fr) * | 2006-09-28 | 2009-02-13 | Veolia Proprete Sa | Dispositif de mesure du debit d'un des constituants d'un fluide multiphasique en ecoulement dans un conduit. |
DE102008055030A1 (de) * | 2008-12-19 | 2010-07-01 | Endress + Hauser Flowtec Ag | Messrohr eines Ultraschall-Durchfluss-Messsystems |
JP2012021899A (ja) * | 2010-07-15 | 2012-02-02 | Panasonic Corp | 超音波流量計測ユニットおよびこれを用いた超音波流量計 |
DE102013105407A1 (de) | 2013-05-27 | 2014-11-27 | Endress + Hauser Flowtec Ag | Vorrichtung zur Bestimmung und/oder Überwachung des Volumen- und/oder Massedurchflusses eines Mediums |
DE102013109349A1 (de) * | 2013-08-29 | 2015-03-05 | Endress + Hauser Flowtec Ag | Ultraschallwandler und Ultraschall-Durchflussmessgerät |
EP3063508B1 (de) | 2013-10-28 | 2018-04-04 | Technical University of Denmark | Durchflussmesser zum ultraschallmessen der strömungsgeschwindigkeit von flüssigkeiten |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2140160A (en) * | 1983-05-21 | 1984-11-21 | Gen Electric Co Plc | Apparatus for sensing the movement of a fluid |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4130018A (en) * | 1977-08-30 | 1978-12-19 | Envirotech Corporation | Ultrasonic transducer with reference reflector |
DE3331531A1 (de) * | 1983-09-01 | 1985-03-21 | Elster AG, Meß- und Regeltechnik, 6700 Ludwigshafen | Verfahren und vorrichtung zum messen der stroemungsgeschwindigkeit von fluiden mittels ultraschall |
-
1993
- 1993-10-16 DE DE19934335394 patent/DE4335394C2/de not_active Expired - Fee Related
-
1994
- 1994-10-13 SK SK447-96A patent/SK44796A3/sk unknown
- 1994-10-13 CZ CZ96924A patent/CZ92496A3/cs unknown
- 1994-10-13 HU HU9600984A patent/HUT73914A/hu unknown
- 1994-10-13 EP EP94930948A patent/EP0706640A1/de not_active Withdrawn
- 1994-10-13 WO PCT/EP1994/003372 patent/WO1995011426A1/de not_active Application Discontinuation
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2140160A (en) * | 1983-05-21 | 1984-11-21 | Gen Electric Co Plc | Apparatus for sensing the movement of a fluid |
Non-Patent Citations (2)
Title |
---|
E.S.IKPE ET AL.: "A standing-wave flow measurement system for small diameter pipes using long acoustic waves", REVIEW OF SCIENTIFIC INSTRUMENTS, vol. 64, no. 9, September 1993 (1993-09-01), NEW YORK US, pages 2666 - 2672, XP000395694 * |
E.S.IKPE ET AL.: "Development of an ultrasonic transducer using long acoustic waves for flow measurement", SENSORS AND ACTUATORS A, vol. 37-38, 1993, LAUSANNE CH, pages 403 - 409, XP000411419 * |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE19648784A1 (de) * | 1996-05-28 | 1997-12-04 | Krohne Ag | Ultraschall-Durchflußmesser |
DE19648784C2 (de) * | 1996-05-28 | 1998-04-09 | Krohne Ag | Ultraschall-Durchflußmesser |
EP0945712A1 (de) * | 1998-03-25 | 1999-09-29 | Siemens-Elema AB | Vorrichtung zum Messen eines Gasflusses |
US6058786A (en) * | 1998-03-25 | 2000-05-09 | Siemens Elema Ab | Device for measuring a gas flow |
DE102006026311A1 (de) * | 2006-06-02 | 2007-12-06 | Endress + Hauser Flowtec Ag | In-Line-Meßgerät mit einem innen mit Polyurethan ausgekleidetem Meßrohr und Verfahren zu dessen Herstellung |
US7523675B2 (en) | 2006-06-02 | 2009-04-28 | Endress + Hauser Flowtec Ag | In-line measuring device with measuring tube lined internally with polyurethane and method for manufacture thereof |
US9782798B2 (en) | 2006-06-02 | 2017-10-10 | Endress + Hauser Flowtec Ag | In-line measuring device with measuring tube lined internally with polyurethane and method for manufacture thereof |
Also Published As
Publication number | Publication date |
---|---|
DE4335394C2 (de) | 1997-02-13 |
HUT73914A (en) | 1996-10-28 |
HU9600984D0 (en) | 1996-06-28 |
CZ92496A3 (en) | 1996-10-16 |
SK44796A3 (en) | 1996-08-07 |
DE4335394A1 (de) | 1995-04-20 |
EP0706640A1 (de) | 1996-04-17 |
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