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WO1990002933A1 - Dispositif ameliore servant a determiner la densite de liquides et de gaz - Google Patents

Dispositif ameliore servant a determiner la densite de liquides et de gaz Download PDF

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Publication number
WO1990002933A1
WO1990002933A1 PCT/SE1989/000461 SE8900461W WO9002933A1 WO 1990002933 A1 WO1990002933 A1 WO 1990002933A1 SE 8900461 W SE8900461 W SE 8900461W WO 9002933 A1 WO9002933 A1 WO 9002933A1
Authority
WO
WIPO (PCT)
Prior art keywords
plate
fact
vibrate
improved gauge
crystals
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/SE1989/000461
Other languages
English (en)
Inventor
Nils Gustav Erik Stemme
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of WO1990002933A1 publication Critical patent/WO1990002933A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N9/00—Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity
    • G01N9/002—Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity using variation of the resonant frequency of an element vibrating in contact with the material submitted to analysis

Definitions

  • This invention relates to an improved gauge for determining the density of stationary as well as streaming fluids and comprises a plate immersed in the fluid.
  • the purpose of the invention is to indicate a gauge of this kind which gives exact values without forces or moments being transferred to the supporting means and a minimum of energy being radiated from the transmitter. These criteria must be fulfilled if results of sufficient exactitude are to be obtained.
  • the invention is characterized thereby that the plate is excited to vibrate in such a manner that four nodal lines are created said nodal lines dividing said plate in four areas of equal size and shape.
  • the plate forms together with an amplifier an oscillating circuit having a frenquency which is influenced by the density of the fluid in such a way that a fluid having high density gives a lower resonance frequency than does a fluid having lower density.
  • Fig. 1 shows a plate according to the invention
  • Fig. 2 shows the same plate mounted in a container with liquid the density of which is to be measured
  • Fig.3 shows the same plate with the streams about the plate being indicated by means of arrows
  • Figs.4, 5, and 6 show some possible forms of the plate
  • Figs.7 and 8 show a plate in two different views, said plate intended specifically for liquids issuing gas, and
  • Figs. 9 and 10 show a modified type of the measuring gauge according to the invention.
  • Fig. 1 shows a vibrating plate 1 according to the invention. This plate is provided with four piezoelectric crystals 2, 3, 4, and 5 arranged diametrically in relation to each other. As shown in Fig.2 this plate shall be immersed in the liquid 6 to be measured. The plate is by means of conductors 7 connected to the computor equipment.
  • Fig. 3 there is shown a completely freely vibrating plate 1 and arrows indicated how by means of vibration the plate is excited to vibrate in such a way that there are formed four converging nodal lines which divide the plate into four areas of equal size and shape.
  • Figs. 4, 5, and 6 show three further possible embodiments for the plate in order to make it clear that the invention by no means is restricted to the embodiment shown in Fig. 3.
  • the part of the liquid situated closest to the vibrating plate is participating in the vibrating movement and streams between the different areas as indicated in Fig. 3.
  • the acoustic radiation will be ⁇ ery low which means that the resonant qualities are well defined and the mechanical Q-value will be high.
  • Figs. 7 and 8 show a device in two directions which are perpendicular to each other. This device is of special use for measuring liquids issuing gas. Gas bubbles adhering to the surface of the transmitter are removed due to the inclining position of the plate. It is also possible to use an electromagnet 8 which excitate the plate to vibrate in its own plane such that gas bubbles which may adhere to the surface of the plate are loosened or liberated.
  • Fig. 10 shows a modified embodiment of the plate 1 with the piezoelectrical crystals 2, 3, 4, and 5. For symmetrical reasons one should use double crystals to excitate and receive and possible alternatives comprise electric-mechanical piezoresistive and piezomagnetic elements.
  • the crystals and conductors are protected by a plastics film but they may as shown in the Figures also be protected by a hood 10.
  • the crystals may also as shown in Figs. 9 and 10 be recessed in the interior of the plate 1 and protected by a disk 11.
  • the plate of the transmitter is preferably manufactured from a special alloy. Ni-span-C or constantan give extremely low temperature dependency.
  • the invention gives a number of advantages such as high exactness, small dimensions (e.g. 10 x 10 x 0.3 mm), low dependency on temperature and pressure as well as simple structure well fitted for mass production.
  • the plate may have other configuration than the ones shown and the attachment and the connection to the electronic equipment for the conversion of the frequence as measured to digital values of the density of the liquid may be accomplished in many different ways known to the artisan. However, this is not within the scope of the invention.

Landscapes

  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
  • Measuring Fluid Pressure (AREA)

Abstract

La jauge améliorée décrite, qui sert à mesurer la densité de fluides aussi bien stationnaires qu'en écoulement, comprend une plaque (1) immergée dans le fluide et excitée en vue de vibrer par deux cristaux piézoélectriques (3, 5 et 2, 4) situés diamétralement à l'opposé l'un de l'autre. Ces cristaux excitent la plaque en vue de sa vibration avec une fréquence telle qu'il se crée quatre lignes nodales convergentes divisant la plaque (1) en quatre zones de surfaces égales. Deux de ces zones situées adjacentes l'une de l'autre vibrent en anti-phase et la plaque (1), qui est l'émetteur, forme avec un amplificateur un oscillateur dont la sortie est connectée à l'équipement électronique qui convertit la fréquence telle qu'elle est mesurée en une valeur numérique.
PCT/SE1989/000461 1988-09-05 1989-09-01 Dispositif ameliore servant a determiner la densite de liquides et de gaz Ceased WO1990002933A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE8803092-9 1988-09-05
SE8803092A SE8803092L (sv) 1988-09-05 1988-09-05 Anordning vid maetare foer bestaemning av vaetskors och gasers densitet

Publications (1)

Publication Number Publication Date
WO1990002933A1 true WO1990002933A1 (fr) 1990-03-22

Family

ID=20373207

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE1989/000461 Ceased WO1990002933A1 (fr) 1988-09-05 1989-09-01 Dispositif ameliore servant a determiner la densite de liquides et de gaz

Country Status (2)

Country Link
SE (1) SE8803092L (fr)
WO (1) WO1990002933A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1992005421A1 (fr) * 1990-09-24 1992-04-02 Hydramotion Limited Instrument de detection vibratile

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2712789B2 (de) * 1976-03-30 1979-11-22 Institut Straumann Ag, Waldenburg (Schweiz) Vorrichtung zum Messen der Dichte flüssiger und gasförmiger Stoffe

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2712789B2 (de) * 1976-03-30 1979-11-22 Institut Straumann Ag, Waldenburg (Schweiz) Vorrichtung zum Messen der Dichte flüssiger und gasförmiger Stoffe

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
DERWENT'S ABSTRACT NO. G3746, K/19; & SU,A,939999, see whole document. *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1992005421A1 (fr) * 1990-09-24 1992-04-02 Hydramotion Limited Instrument de detection vibratile
GB2263773A (en) * 1990-09-24 1993-08-04 Hydramotion Ltd Vibratile sensing instrument
GB2263773B (en) * 1990-09-24 1994-08-03 Hydramotion Ltd Vibratile sensing instrument
US5363691A (en) * 1990-09-24 1994-11-15 Hydramotion Limited Vibratile sensing instrument

Also Published As

Publication number Publication date
SE8803092L (sv) 1990-03-06
SE8803092D0 (sv) 1988-09-05

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