摘要:
L'invention concerne un procédé pour la détermination de la masse volumique d'un fluide. A cet effet, il comprend les étapes consistant à :
placer le fluide dans un réservoir (1) ; immerger dans le fluide deux flotteurs (13, 14) présentant des flottabilités différentes ; relier lesdits flotteurs à la structure (15) du réservoir par des moyens (16, 17) aptes à s'opposer aux efforts de flottabilité ; procéder à une double détection de grandeurs fonctions des positions d'équilibre des flotteurs ; et déduire la masse volumique du résultat de cette double détection.
摘要:
A float constituted by a hollow body of a dielectric material (5) having on the top a metallic conducting disk (16) made from a non ferromagnetic material and on the bottom a permanent magnet (6), is immerged in the liquid (2) in a chalix shaped container (7) where on the exterior of the hollow stem there is a winding (8) constituting an electromagnet driven by the current supplied by the differential amplifier (12). The float (5, 6, 16) assumes in the liquid a fixed position in virtue of feed-back effect produced by eddy currents positionvoltage transducer (18, 15, 17). The current flowing in the electromagnet is proportional, at less than a constant due to the weight of the float (5, 6, 16) to the hydrostatic buoyancy that is to say, to the specific gravity of the liquid. The fixed position of the float (5, 6, 16) makes the measure independent by the spatial non linearities of the magnetic field and, by non linearity of the positionvoltage transducer (18, 15, 17). The centering action of electromagnet (8) on the magnet (6) avoids the friction with the walls around the float (5, 6, 16), that remain suspended in the liquid.
摘要:
A sensor for sensing buoyancy force within a liquid mixture (4) stored within a storage tank (2) and an interlock employing the sensor (10) to prevent a respirable cryogenic mixture from being dispensed from the storage tank (2) with an unsafe oxygen content. The sensor (10) has a float (12) adapted to be submerged in the liquid mixture (4), thereby to exert a buoyancy force referable to the density. The buoyancy force is sensed by a load cell(26) connected to an elongate base element (18) cantilevered from the outlet (3) of the tank (2) by a bracket (38). The mounting of such sensor (10) ensures that the buoyancy force and therefore, the density of the liquid as dispensed will be measured as opposed to liquid density at some other location of the tank (2). Such sensor (10) can serve in an interlock in which a controller (32) responsive to the load cell (26) and a temperature sensor (34), also located within the outlet (3), controls a valve (36) to close the outlet (3) when the mixture has an unsafe oxygen level.
摘要:
An electronic hydrometer (10) for determining the density of a liquid, the hydrometer comprising a housing (11) having a liquid receiving chamber (13) and means to insert a liquid of which the density is to be determined in the chamber. A float (22) having a known weight is disposed in the chamber. A connecting shaft (24) is secured to the float and retained for guided displacement along its longitudinal axis in response to introduction of a predetermined quantity of liquid in the chamber. A sensor (29) is associated with a shaft for detecting a reference position of the shaft. A permanent magnet 30 is mounted in proximity of the shaft and has a magnetic core (31) and a displacement coil (32) about the core. The coil is secured to the shaft. An electronic circuit means automatically adjusts the valve of a current flowing in the coil to displace the coil and the shaft relative to the reference position. The value of the adjusted current is calibrated by the circuit to generate an output signal indicative of the density of the liquid in the chamber.
摘要:
The invention relates to a measuring device for measuring the specific weight of liquids, provided with an oblong housing (1) to be immersed in the liquid, a cavity (8) being present lengthways in said housing, which cavity can admit the liquid through openings (4) in the base of the housing, a body (5) provided with a ferromagnetic core (6) and which is freely movable lengthways of said cavity being present within the cavity (8) and a lift-up coil (2) being present in said housing (1) about the cavity (8). The invention particularly relates to the fact that an inductive displacement recorder (3) is placed in the housing (1) about the cavity practically on a level with the ferromagnetic core (6) in the case of a currentless lift-up coil (2), which recorder (3) only emits a signal after placement of the housing (1) in a liquid, if such an increasing direct current is periodically passed through the lift-up coil (2) so that the body (5) with the ferromagnetic core (6) moves lengthways from the raised position from a mechanical stop (7) after initially having raised itself within the liquid lengthways of the cavity (8), the direct current throught the lift-up coil (2) being a measure for the specific weight of the liquid at the moment when the displacement recorder (3) emits a signal.
摘要:
An apparatus arranged to measure specific gravity / density of a quantity of fluid (12), comprising a displacement means (2) arranged to be suspended into the fluid (12) such that it is completely submerged and displaces a portion of the fluid (12), a weight measuring means (4) arranged to measure the resultant force exerted by the displacement means (2) and a processing means arranged to process the resultant force and produce a reading (13) of the specific gravity / density for the fluid (12). The apparatus allows temperature compensation to be performed such that a reading can be made at a first temperature and the specific gravity / density calculated at a second different temperature.
摘要:
A fluid density measurement device includes a float (12) and a weight (14), each mounted on links (16) for essentially vertical movement. A crank (22) is mounted above the float and weight and is connected to them by a float link (24) and a counterweight link (28) to convert the forces from the float and the forces from the weight to rotational forces on the crank acting in opposite directions. The position adopted by the crank will be dependent upon the density of the fluid in which the instrument is immersed. The links (16) are arranged so that a good approximation to straight line motion is obtained at the centre of the float and the weight.
摘要:
Eine Vorrichtung zum Bestimmen der Dichte einer Flüssigkeit enthält einen Auftriebskörper (20), mindestens eine an dem Auftriebskörper (20) angreifende Messfeder (30, 40), deren elastische Deformation ein Maß für die Auftriebskraft des Auftriebskörpers (20) ist, und einen Magneten (28), der für die Erfassung der elastischen Deformation der Messfeder (30, 40) mittels eines magnetostriktiven Positionsmesssystems eingerichtet ist. Der Quotient aus Masse und Volumen des Auftriebskörpers (20) ist größer als die zu bestimmende Dichte, wie es bei der Anwendung in Flüssiggasen der Fall ist. Der Auftriebskörper (20) wird durch Federkraft in Richtung der Auftriebskraft in einen Arbeitsbereich der Messfeder (30, 40) vorgespannt.