• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The invention relates to a measuring device for the examination of fluid samples, comprising a bending oscillator (15) whose oscillator tube (2) is fixed to at least one clamping point (5) and on one side of the clamping point (5), in particular carrier unit, a cantilevered oscillator section (16) and on the other side has a fluid supply pipe section (17) with a feed opening and a Fluidableitrohrabschnitt (18) having a Fluidableitöffnung. According to the invention, it is provided that the oscillator tube (2) is fixed or retained both on its fluid discharge tube section (17) and on its fluid supply tube section (18) with at least one separate holding device (7) provided in addition to the clamping point (5).
    公开号:AT517082A4
    申请号:T50409/2015
    申请日:2015-05-20
    公开日:2016-11-15
    发明作者:Wolfgang Belitsch；Patrick Trummer；Robert Breidler
    申请人:Anton Paar Gmbh；
    IPC主号:
    专利说明:

    The invention relates to a measuring device for density determination of fluids, in particular a measuring device according to the preamble of patent claim 1.
    The principle of density measurement of liquid or gaseous fluids by means of a vibrating glass tube filled with the fluid to be measured is known. The measurement of the density of fluid media with a flexural vibrator is based on the fact that the vibration of a hollow body filled with a sample to be examined depends on the filling of the vibrator tube, i. of the mass or, if the volume is constant, of the density of the filled medium.
    The measuring cell of a measuring device contains as a vibrating structure a hollow, usually U-shaped bent, glass or metallic oscillating tube. This is excited electronically to a vibration. The two legs of the U-shaped tube form the spring elements of the vibrator. The natural frequency of the U-shaped vibrator tube is only affected by that part of the sample that actually participates in the vibration. This participating in the vibration volume V is limited by the stationary vibration nodes at the clamping points of the vibrator tube. If the oscillator tube is filled with the sample at least up to these clamping points, the same, precisely defined volume V always participates in the oscillation and the mass of the sample can therefore be assumed to be proportional to its density. Overfilling of the vibrator beyond the clamping points is irrelevant to the measurement. For this reason, the oscillator can also be used to measure densities of fluids that flow through the oscillator.
    The density of the liquid thus determines the specific frequencies at which the U-shaped tube oscillates. When using precision glass tubes or metal tubes, their vibration characteristics vary depending on the density and viscosity of the liquid. The resonance frequencies are evaluated by suitable excitation and decrease of the vibrations and from the period duration the density of the filled fluid sample is determined. The transducer is adjusted with fluids of known density and so the measurements are evaluable. For the period P and the density p is generally:
    Such density oscillators or bending oscillators are created in various embodiments with respect to excitation and decrease of the vibration. The
    Excitation and decrease of the resulting natural oscillations occurs e.g. by means of magnetic coils and magnets, piezoelectric elements, capacitive sensing, etc. Depending on the type of excited vibration, a distinction is made between different forms of bending vibrators. Y-oscillators consist of a U-shaped bent tube with parallel legs and swing perpendicular to the plane formed by the two legs of the vibrator. Here, a relatively large countermass is required to ensure that the vibration is determined purely by the spring mass system consisting of U-tube and sample.
    So-called X-oscillators, in which the legs of the U-tube symmetrically oscillate against each other, do not require a counterweight, as here lift errors due to the symmetric oscillation image. Here, on the one hand oscillators with two legs with a deflection similar to a U-tube are known, but on the other hand, so-called Doppelbugschwinger in which two parallel U-tubes oscillate against each other.
    In principle, such oscillators can be made of metal and glass. However, preference is given to glass oscillators because of their high resistance to aggressive media, e.g. Solvents, acids, bases etc. At the same time, the filling can also be visually inspected and / or detected optically with the naked eye and / or a camera in such glass oscillators.
    As a rule, such oscillators are still surrounded by a glass housing and designed as a measuring cell, which housing protects the oscillator from environmental influences. In order to produce good thermal contact with a tempering unit, these measuring cells are filled with hydrogen, for example.
    The glass tube is usually filled or flowed through by means of a syringe or an automatic sample filling unit with the fluid to be measured, wherein the fluid is introduced with the syringe into the glass tube at an inflow opening via a plastic grommet, passes through the oscillator and again at the outflow opening via a plastic grommet expires. The plastic sheaths are attached either to the transducer housing or the support of the housing, this is done for example by screwing or clamping the spouts. The grommets are of course mounted so that they do not protrude into the volume contributing to the measurement of the vibrator. Preferred spout materials are durable plastics such as PTFE (polytetrafluoroethylene), FEP (perfluoroethylene propylene).
    Since the transition between plastic grommet and glass tube must be airtight, the plastic grommets are pressed against the glass tube with relatively great force, which leads to mechanical stresses in the glass tube. It has been shown that these strains affect the resonance frequency of the glass tube and thus have a negative effect on the accuracy of the density measurement, especially if a large syringe (eg 10ml) is directly attached to the plastic sheaths or if the temperature of the measuring cell is changed Length change in the oscillator in the manner of a strained spring leads to a change in the natural frequency.
    Exact inspection of vibrators during the measurement shows that the insertion of the grommets already leads to different loads and is heavily operator-dependent. Images of the oscillator under polarized light show that the glass webs that carry the oscillator or connect to the surrounding device housing and thus also with the counterweight, are not uniformly loaded by the pressure of the connecting sleeves, resulting in mechanical stresses in the glass body in the connection area between oscillator and housing leads. These voltages have a direct influence on the natural frequency of the vibrator and lead to inaccuracies in the vibration behavior.
    When the measurement temperature changes, the change in the strain in the glass due to the changing contact force due to the grommets leads to inaccuracies in the natural frequency or damping and thus also to errors in the measured density or viscosity correction. Sometimes it may even be necessary for the device to be readjusted by measuring standards.
    This also applies to the necessary for a temperature-dependent measurement temperature of the vibrator. Again, these tensions lead to a slower approximation of the stable measured values and also by the hysteresis of the glass when passing through temperature ramps leads to inaccuracies in the natural frequency or damping and thus also in the determined density or viscosity correction.
    In the worst case, therefore, the oscillator, especially for highly accurate measurements to the 6th decimal place, ie + - 10 E - 6 g / cm3, must be readjusted after passing through temperature curves by measurement with standards.
    These effects due to mechanical stresses in the glass were hitherto completely unknown and were demonstrated by highly accurate polarization images of the oscillator during the experimental procedure by means of measurements for repeatability.
    In order to reduce these tensions, for example, the oscillator could be attached more stably to the housing or the oscillator tubes in the filling area could be reinforced. However, this is limited by the cooling behavior of the glasses, because the oscillators can break due to the stresses occurring during cooling.
    According to the invention, a measuring device of the type mentioned above is characterized in that the oscillator tube is fixed or held both at its Fluidableitrohrabschnitt and at its Fluidzufuhrrohrabschnitt with at least one additional provided in addition to the clamping, independent holding device. In particular, can be mechanically decoupled by an additional support web of the bending oscillator of the connection or clamping point and thus both the bending vibrator and a reference oscillator can be protected from excessive tension. Thus, the primary object of the invention is achieved to minimize or suppress the connection effect of grommets in a glass oscillator and thus to improve the accuracy of the measurement. Furthermore, the problem of the behavior of the measuring cell due to tension occurring after a temperature change of the measuring cell is solved.
    As a clamping point, all known devices for clamping and holding of transducer tubes can be used.
    The invention thus provides an additional reinforcement at a certain point of the oscillator tube. This stiffening has the task to take on the spout of a supply unit, in particular a syringe, introduced on the oscillator tube forces and, preferably to the meter housing, divert. It is noted that the stiffening is not identical with a possibly provided web which carries a reference oscillator. The stiffening or the holding web can also serve as a connecting web between the sections of the oscillator tube in the supply and discharge area. The exact position and orientation, i. a straight or oblique course to the oscillator tube, the stiffening or holding device may vary. The stiffening is, however, in principle in the area between the Tüllenanschluss and the clamping point of the oscillator tube.
    It is possible in principle that the reference oscillator is not connected directly to the web carrying the oscillator tube or to this web, but not too close to the housing. By pressing the grommets into the body of the reference oscillator, however, mechanical stresses are also generated at these webs carrying the oscillator tube or the reference oscillator, which have a negative effect on the oscillation behavior of the reference oscillator. With the holding device provided according to the invention, however, such tensions are also minimized.
    Suitable as a holding device is any, preferably rigid, connection between a cladding tube or housing of the bending oscillator or measuring device housing and the two fluid connection sections of the oscillator tube.
    Everything that lies on the tube side of the clamping point or the Einspannsteg the transducer tube is to be regarded with respect to the vibrator as infinitely stiff; Tensions occurring there are minimized according to the invention.
    The invention is particularly advantageous if, in addition to the bending oscillator, a reference oscillator is provided, since this benefits from the provided stiffening of the oscillator tube of the bending oscillator by the holding device and can also be operated more accurately. It is possible to fix the reference oscillator to a glass frame of the measuring device or to arrange it on the oscillating tube or on the carrier or web carrying it.
    The reference oscillator may be formed by a U-tube or a simple glass rod, in particular to correct the aging behavior and the thermal hysteresis of the glass used. In any case, the undesirable effects of connecting spouts can be eliminated.
    In preferred cases, the reference oscillator can be excited to oscillate with the same excitation system as the measuring transducer or oscillator tube. This allows easier production with fewer parts.
    A structurally simple construction of the measuring device results if the holding device is formed by at least one holding web or holding tube fastened to the housing and / or frame of the measuring device and to the fluid supply pipe section and / or the fluid discharge pipe section.
    If it is provided that the oscillator tube at two clamping points, in particular support units, set and optionally therebetween with a
    Schwingungsanregereinheit is connected, it is advantageous if the holding device is connected outside of the clamping points limited portion of the vibrator tube to the fluid supply pipe section and fluid discharge pipe section of the vibrator tube. In practice, it is advantageous if the oscillator tube carries in its course between its two clamping points a reference bending oscillator or the, preferably formed by carriers, clamping points of the reference oscillator.
    A stable structure and a good support or vibration damping and avoidance of stress is achieved when the holding device or the holding web or the holding tube is connected on both sides of the oscillator tube with respect to the oscillator tube opposite positions with the housing and / or frame of the measuring device and / or if the holding device or the holding web surrounds the oscillator tube in the region of the fluid supply pipe section and the fluid discharge pipe section, advantageously on all sides or over this entire circumference, or if these two sections are guided by the holding web and are connected with these in a positionally invariable manner.
    Of particular advantage is the invention, if it is provided that are connected to the fluid supply pipe and the Fluidableitrohrabschnitt or fluid supply side and fluidableitseitig the clamping point on the vibrator tube grommets for connecting a Fluidzu-and-derivative and / or that the oscillator tube and / or the holding device or the holding web and / or a carrier forming the clamping consist of glass.
    In a preferred embodiment it is provided that the nozzles connected to the fluid supply pipe section and fluid discharge pipe section of the oscillator pipe are connected to a holder with the housing and / or frame.
    It is quite possible that the holding device comprises a holding web for the fluid feed pipe section and a holding web for the fluid discharge pipe section, which connects the respective pipe section to the housing and / or the frame and immobilizes movement.
    In the following the invention will be explained in more detail with reference to the drawings, for example.
    Fig. 1 shows a measuring device according to the invention in a schematic section. FIGS. 2a and 2b show two different embodiments of measuring probes in a schematic section. FIGS. 3a and 3b show some schematic embodiments of measuring devices according to the invention.
    1 shows a measuring device 1, which is arranged within a tempering chamber 30 and comprises a measuring device housing 3, which is arranged on a frame 10, which frame 10 also serves as counterweight or for temperature control of the sensor housing. On the frame 10 or within the meter housing 3 and connected to this is a carrier which forms the clamping point 5 for the oscillator tube 2 of a bending oscillator. The fixed in the clamping point 5 transducer tube 2 can be excited in its cantilevered oscillator section 16 with a vibration excitation unit 12 to vibrate. The clamping point 12 of the oscillator tube 2 of the bending oscillator 15 holds this, with the sections of the oscillator tube 2 being located on the side of the clamping point 12 opposite the oscillator section 16, which serve for fluid supply or fluid discharge into or out of the oscillator tube 2. This Fluidzufuhrrohrabschnitt 17 and Fluidableitrohrabschnitt 18 are set with a provided in addition to the clamping point 5 holding device 7 in the present case, a web or held vibrationally invariant. The holding device 7 is connected to the measuring device housing 3 and / or to the frame 10. To the fluid supply pipe section 17 and the Fluidableitrohrabschnitt 18 spouts 8 are connected, with which the fluid to be examined according to the arrows 14 can be fed to the bending oscillator 15 and derived from this.
    The spouts 8 are attached to the transducer tube 2, preferably fluid-tight, attached or attached to this and fluid-tight with this.
    The holding device 7 may be formed in the form of a round or square or other profile having web; the holding device 7 can also be formed by a tube.
    The carrier forming the clamping point 5 can also carry a carrier 6, from which a reference bending oscillator 4 is carried.
    FIGS. 2 a and 2 b show a bending oscillator approximating the practice in section. The curved support 6 carries the reference oscillator 4 and starts from the carrier of the clamping point 5 of the oscillator tube 2 of the bending oscillator 15.
    As can be seen from FIG. 1, the vibration excitation takes place with a schematically illustrated vibration excitation unit 12 in the region in front of the clamping point 5 in the freely protruding oscillator section 16.
    It can be seen from FIGS. 2 a and 2 b that in this embodiment the holding device 7 is formed by a web which connects the fluid discharge tube section 18 of the oscillator tube 2 to the housing 3, which has the enlarged diameter relative to the freely projecting oscillating section 16. The fluid supply pipe portion 17 is set in the same manner.
    If the oscillator tube 2 is fixed at two clamping points 5, as shown in FIGS. 3 a and 3 b, the vibration excitation unit 12 can lie between the two clamping points 5. The clamping points 13 of a directly attached to the oscillator tube 2 of the bending oscillator 15 reference vibrator 4 are located between the two clamping points 5 of the oscillator tube 2. In the fluid supply pipe section 17 and in the Fluidableitrohrabschnitt 18, the oscillator tube 2 is fixed to the holding device 7, which is shown in FIG Wall of the meter housing extends to the transducer tube 2.
    In the embodiment according to FIG. 3 b, the two clamping points 13 of the reference oscillator 4 lie against the wall of the housing 3.
    As can be seen from FIG. 2a, the fluid supply pipe section 17 and the fluid discharge pipe section 18 can be made through the holding web of the holding device 7 and held in this way.
    Above all, the use of the invention is advantageous if the oscillator tube 2 and the holding device 7 are formed of glass, since there is no attack of aggressive media.
    Finally, it is also possible to connect the grommets 8 with the housing 3 of the measuring device 1 in order to store the grommets 8 largely motion-invariant for the measurement.
    权利要求:
    Claims (10)
    [1]
    claims:
    1. A measuring device for the examination of fluid samples, comprising a bending oscillator (15) whose oscillator tube (2) is fixed to at least one clamping point (5) and on one side of the clamping point (5), in particular carrier unit, a cantilevered oscillator section (16 ) and on the other side a fluid supply pipe section (17) having a feed opening and a Fluidableitrohrabschnitt (18) having a Fluidableitöffnung, characterized in that the oscillator tube (2) both at its Fluidableitrohrabschnitt (17) and at its Fluidzufuhrrohrabschnitt (18) with at least one in addition to the clamping point (5) provided, independent holding device (7) is fixed or held.
    [2]
    2. Measuring device according to claim 1, characterized in that the holding device (7) of at least one of the housing (3) and / or frame (10) of the measuring device (1) and the fluid supply pipe section (17) and / or on the Fluidableitrohrabschnitt (18) fixed holding web or holding tube is formed.
    [3]
    3. Measuring device according to claim 1 or 2, characterized in that - the oscillator tube (2) with two clamping points (5), in particular carrier units, fixed and optionally connected therebetween with a vibration excitation unit (12), and - that the holding device (7) outside of the clamping points (5) limited portion of the oscillator tube (2) with the fluid supply pipe section (17) and Fluidableitrohrabschnitt (18) of the oscillator tube (2) is connected.
    [4]
    4. Measuring device according to one of claims 1 to 3, characterized in that the oscillator tube (2) in its course between its two clamping points (5) a reference bending oscillator (4) or, preferably formed by carriers, clamping points (13) of the reference oscillator (4) carries.
    [5]
    5. Measuring device according to one of claims 1 to 4, characterized in that the holding device (7) or the holding web or the holding tube on both sides of the oscillator tube (2) with respect to the oscillator tube opposite points with the housing (3) and / or Frame (10) of the measuring device (1) is connected.
    [6]
    6. Measuring device according to one of claims 1 to 5, characterized in that at the Fluidzufuhrrohrabschnitt (17) and the Fluidableitrohrabschnitt (18) or fluid supply side and fluidableitseitig the clamping point (5) on the oscillator tube (2) spouts (8) for connecting a Fluidzu- and derivative are connected.
    [7]
    7. Measuring device according to one of claims 1 to 6, characterized in that the holding device (7) or the holding web, the oscillator tube (2) in the region of the fluid supply pipe section (17) and the Fluidableitrohrabschnitts (18), advantageously on all sides or over this entire Scope, surrounds or these two sections (17, 18) carried out by the holding web and connected to these are connected in a position invariant.
    [8]
    8. Measuring device according to one of claims 1 to 7, characterized in that the oscillator tube (2) and / or the holding device (7) or the holding web and / or a clamping point (5) forming carrier consist of glass.
    [9]
    9. Measuring device according to one of claims 1 to 8, characterized in that the fluid supply to the pipe section (17) and Fluidableitrohrabschnitt (18) of the oscillator tube (2) connected spouts (8) with a holder to the housing (3) and / or frame (10) are connected.
    [10]
    10. Measuring device according to one of claims 1 to 9, characterized in that the holding device (7) comprises a holding web for the Fluidzufuhrrohrabschnitt (17) and a holding web for the Fluidableitrohrabschnitt (18), the respective pipe section (17, 18) with the Housing (3) and / or the frame (10) connects and determine movement invariant.
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    同族专利:
    公开号 | 公开日
    US20160341644A1|2016-11-24|
    CN106168566A|2016-11-30|
    EP3101409A1|2016-12-07|
    AT517082B1|2016-11-15|
    JP2017021008A|2017-01-26|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US4803867A|1987-04-28|1989-02-14|Dahlin Erik B|Fluid measurement apparatus providing flow tube strain relief|
    AT394784B|1990-11-22|1992-06-25|Hans Dr Stabinger|DEVICE FOR DETERMINING THE DENSITY OF LIQUIDS AND GAS FROM THE PERIOD OF A VIBRATOR FILLED WITH A PREPARATION|
    EP1253408A1|2001-04-24|2002-10-30|Endress + Hauser Flowtec AG|Vibration type measuring transducer|
    US7735353B2|2006-06-20|2010-06-15|Rudolph Research Analytical|Method and apparatus for oscillating a test sample|
    DE102009031471A1|2009-07-01|2011-01-05|Mettler-Toledo Ag|Measuring device for density determination|
    CN102797453B|2012-08-14|2015-04-29|北京科力博奥仪表技术有限公司|Well logging densimeter|
    CN103424336A|2013-07-23|2013-12-04|北京奥普科星技术有限公司|Double U-shaped vibrating pipe type fluid density sensor|AT522901A1|2019-09-03|2021-03-15|Anton Paar Gmbh|Measuring device for examining the density of fluid samples|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    ATA50409/2015A|AT517082B1|2015-05-20|2015-05-20|Measuring device for the examination of fluid samples|ATA50409/2015A| AT517082B1|2015-05-20|2015-05-20|Measuring device for the examination of fluid samples|
    EP16169826.1A| EP3101409A1|2015-05-20|2016-05-17|Measuring apparatus for analyzing fluid samples|
    CN201610336575.XA| CN106168566A|2015-05-20|2016-05-20|For determining the measuring instrument of fluid density|
    US15/160,396| US20160341644A1|2015-05-20|2016-05-20|Measuring instrument for determining the density of fluids|
    JP2016101432A| JP2017021008A|2015-05-20|2016-05-20|Measuring instrument for measuring fluid sample|
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