DD252438A1

DD252438A1 - rotational viscometer

Info

Publication number: DD252438A1
Application number: DD29351686A
Authority: DD
Inventors: Dieter Hemmecke
Original assignee: Medizin Labortechnik Veb K
Priority date: 1986-08-08
Filing date: 1986-08-08
Publication date: 1987-12-16
Also published as: DE3714708A1; CH672372A5

Abstract

Die Erfindung betrifft ein Rotationsviskosimeter, wie es zur kontinuierlichen Bestimmung der Viskositaet fliessfaehiger Medien in Rohrleitungen und Behaeltern innerhalb von Produktionsprozessen und in Pilotanlagen Anwendung findet. Mit der Erfindung sollen fehlerhafte Messergebnisse vermieden und die Leistungsparameter des Viskosimeters verbessert werden. Die Lagerreibungsmomente und der Schlupf sollen gering gehalten, ein ausreichender Messsubstanzaustausch gewaehrleistet und Betriebsstoerungen infolge zu geringer Innenringspalte ausgeschaltet werden. Realisiert wird dies, indem zwei erste diametrisch magnetisierte Permanentmagnete am aeusseren Umfang eines zentrisch und drehbar in einem Messbehaelter gelagerten Rotors angeordnet sind und dass ein weiterer, mit einer Antriebswelle verbundener, ebenfalls diametral magnetisierter in einem ortsfesten, koaxial zum Rotor angeordneten, zwischen die ersten Permanentmagnete eintauchenden und zwischen diesen ersten Permanentmagneten und dem weiteren Permanentmagnet eine Trennwand bildenden nichtmagnetischen Innenzylinder hineinragt. Fig. 1The invention relates to a rotational viscometer, as it is used for the continuous determination of Viskositaet flowable media in pipelines and containers within production processes and in pilot plants application. The invention is intended to avoid erroneous measurement results and to improve the performance parameters of the viscometer. The bearing friction torques and slippage should be kept low, a sufficient exchange of measuring substances ensured and malfunctions due to insufficient inner annular gaps eliminated. This is realized by two first diametrically magnetized permanent magnets on the outer circumference of a centrally and rotatably mounted in a Meßbehaelter rotor are arranged and that another, connected to a drive shaft, also diametrically magnetized arranged in a stationary, coaxial with the rotor, between the first permanent magnets immersed and between these first permanent magnet and the further permanent magnet, a partition wall forming non-magnetic inner cylinder protrudes. Fig. 1

Description

embodiment

Mit einem Ausführungsbeispiel soll anhand einer Zeichnung die Erfindung näher erläutert werden. Es zeigen:With one embodiment, the invention will be explained in more detail with reference to a drawing. Show it:

Fig. 1: die Meßzelle des Rotationsviskosimeter im SchnittFig. 1: the measuring cell of the rotational viscometer in section

Fig.2: Schnitt A-A zu Fig. 1 mit Hohlzylinderrotor2: Section A-A to Fig. 1 with a hollow cylinder rotor

Fig. 3: horizontaler Schnitt einer Meßzelle mit Flügelrotor.Fig. 3: horizontal section of a measuring cell with vane rotor.

Wie in Fig. 1 dargestellt, ist in dem als Meßbehälter ausgebildeten vom Flansch 1 verschlossenen ortsfesten Außenzylinder 2 der Rotor 3 zentrisch gelagert. Der Rotor 3 besitzt am äußeren Umfang zwei erste diametral magnetisierte zylinderförmige Permanentmagnete 4. Gelagert ist der Rotor 3 mit seinem unteren Wellenende 5 im Boden 6 des Außenzylinders 2, mit seinem oberen Wellenende 7 im Boden 8 des mit dem Flansch 1 ein Teil bildenden ebenfalls ortsfesten Innenzylinder 9. Der Innenzylinder 9 erstreckt sich koaxial zur Rotorwelle 10 und nimmt einen weiteren, diametral magnetisierten zylindrisch ausgebildeten Permanentmagnet 11 auf, der über die Antriebswelle 12 von einem nicht dargestellten Elektromotor angetrieben wird. Der Rotor 3 ist als Hohlzylinder ausgebildet. Der den weiteren Permanentmagnet 11 aufnehmende Innenzylinder 9 bildet zugleich die Trennwand 13 zwischen dem Permanentmagnet 11 und den beiden ersten Permanentmagneten 4. Der von der Innenwand 14 des Außenzylinders 2 und der Außenwand 15 des Innenzylinders 9 sowie dem Boden 6 und den Flansch 1 begrenzte Meßraum 16 wird durch den Rotor 3 und die darauf sitzenden ersten Permanentmagnete 4 in die beiden Ringspalte 17a, 17 b geteilt. Die Zufuhr der Meßsubstanz in den Meßbehälter 2 erfolgt durch den Zulaufschlitz 18, der Ablauf durch den Ablaufschlitz 19. Das Rotationsviskosimeter arbeitet wie folgt. Nachdem die Meßsubstanz über den Zulaufschlitz 18 in den Meßbehälter 2 gelangt ist und diesen aufgefüllt hat, wird der nichtdargestellte Elektromotor eingeschaltet und der Permanentmagnet 11 im Innenzylinder 3 über die Antriebswelle 12 in eine konstante Winkelgeschwindigkeit versetzt. Dabei erzeugt der Permanentmagnet 11 ein großes magnetisches Drehfeld, das auf die am Rotor 3 angeordneten ersten Permanentmagnete 4 einwirkt und den Rotor 3 dadurch in Drehung versetzt. Der Drehbewegung entgegen wirkt das durch das Medium und die Gerätedimensionierung bedingte Meßmoment. Das Meßmoment wird in einem nicht dargestellten Torsionsdynamometer erfaßt und als ohmsches bzw. kapazitives oder induktives Signal dem Wandler zur Bildung des Einheitssignales, z. B. 4...2omA zugeführt, welches Rechner bzw. Reglersysteme verarbeiten.As shown in Fig. 1, the rotor 3 is mounted centrally in the formed as a measuring container from the flange 1 fixed stationary outer cylinder 2. The rotor 3 has on the outer circumference two first diametrically magnetized cylindrical permanent magnets 4. The rotor 3 is mounted with its lower end 5 in the bottom 6 of the outer cylinder 2, with its upper end of the shaft 7 in the bottom 8 of the flange 1 forming a part also stationary Inner cylinder 9. The inner cylinder 9 extends coaxially with the rotor shaft 10 and receives a further, diametrically magnetized cylindrical permanent magnet 11 which is driven via the drive shaft 12 by an electric motor, not shown. The rotor 3 is designed as a hollow cylinder. The inner cylinder 9 accommodating the further permanent magnet 11 also forms the partition wall 13 between the permanent magnet 11 and the first two permanent magnets 4. The measuring chamber 16 bounded by the inner wall 14 of the outer cylinder 2 and the outer wall 15 of the inner cylinder 9 and the base 6 and the flange 1 is divided by the rotor 3 and the seated thereon first permanent magnets 4 in the two annular gaps 17a, 17b. The supply of the measuring substance into the measuring container 2 is carried out through the inlet slot 18, the drain through the discharge slot 19. The rotational viscometer operates as follows. After the measuring substance has passed through the inlet slot 18 in the measuring container 2 and has filled this, the unillustrated electric motor is turned on and the permanent magnet 11 is displaced in the inner cylinder 3 via the drive shaft 12 in a constant angular velocity. In this case, the permanent magnet 11 generates a large magnetic rotating field, which acts on the first permanent magnets 4 arranged on the rotor 3 and thereby causes the rotor 3 to rotate. The rotational movement counteracts caused by the medium and the device dimensioning measurement torque. The measuring torque is detected in a Torsionsdynamometer, not shown, and the ohmic or capacitive or inductive signal to form the unit signal, z. B. 4 ... 2omA supplied processing computer or controller systems.

Der kontinuierliche Mediumaustausch erfolgt über die dem Gerät eigenen Zu- und Ablaufschlitze 18,19 und der Drehbewegung des Rotors 3.The continuous medium exchange takes place via the device own inlet and outlet slots 18,19 and the rotational movement of the rotor. 3

Claims

1. rotational viscometer, characterized in that two first, diametrically magnetized ^ permanent magnets (4) on the outer circumference of a centrally and rotatably mounted in a measuring container (2) mounted rotor (3) and that another, with a drive shaft (12) connected diametrically magnetized further permanent magnet (11) in a stationary, coaxial with the rotor (3) arranged between the first permanent magnets (4) and between the permanent magnet (4) and the further permanent magnet (11) forming a partition wall (13) forming non-magnetic inner cylinder (9) protrudes.

2. Rotary viscometer according to claim 1, characterized in that the rotor (3) is designed as a hollow cylinder.

3. rotational viscometer according to claim 1, characterized in that the rotor (3) is designed as a vane rotor.

For this 1 page drawings

Field of application of the invention

The invention relates to a rotational viscometer as it is used for the continuous determination of the viscosity of flowable media in pipelines and containers within production processes and in pilot plants.

Characteristic of the known state of the art

The "Fachlexikon für Messtechnik" Authors' Collective, VEB Fachbuchverlag Leipzig 1984, pp. 526/527 describes a rotational viscometer which has as a measuring sensor a rotating cylinder which is surrounded by a coaxially fixed outer cylinder (Searle type) In another embodiment (Couette type), the outer cylinder rotates with the inner cylinder stationary, and a Searle-Couette version with two stationary cylinders is known, creating a double-ring gap. The transmission of the torque and the rotational movement from the unpressurized space into the pressure chamber is effected by a permanent magnet front rotary coupling with a rotating inner cylinder and permanent magnet central rotary couplings in hollow cylinders This viscometer has the disadvantage that the bearing of the rotating measuring cylinder and the permanent magnet (-. Systems) caused by axially acting coupling force large axial need to absorb forces. The undesirably high bearing friction torques enter into the measurement result as errors.

There are viscometer known (DE-AS 1673190, G oil N, 11/14), which are equipped with a rotating outer cylinder and a torque-measuring inner cylinder. These require two permanent magnet clutches. Rotational viscometers with permanent magnet central couplings, which are known to reduce the magnetic flux of the axially directed permanent magnet via soft iron embedding of the rotor, have the disadvantage that the inner annular gap can only have relatively small dimensions, so that sufficient coupling torques are possible at high mass moments of inertia of the rotating cylinder. Too small an inner annular gap can lead to jamming due to the particles occurring in the measuring substance and allow only small measuring ranges. Another disadvantage is the insufficient Meßsubstanzaustausch that occurs when due to a large inner ring gap, the slip between the outer cylinder and inner cylinder exceeds the acceptable size.

Object of the invention

The invention has the aim of designing a rotational viscometer so that erroneous measurement results are excluded and the performance parameters are improved.

Explanation of the essence of the invention

The invention had the object to develop a rotational viscometer in which the bearing friction torques are relatively low, which ensures a sufficient Meßsubstanzaustausch, avoided in the malfunction of jamming of particles and the slip can be kept low.

According to the invention the object has been achieved by two first diametrically magnetized permanent magnets are arranged on the outer circumference of a centrally and rotatably mounted in a measuring container rotor and that another, connected to a drive shaft diametrically magnetized permanent magnet arranged in a stationary, coaxial with the rotor, between the Permanent magnets immersed and between the permanent magnet and the other individual permanent magnet a partition wall forming non-magnetic inner cylinder protrudes, wherein the rotor is designed either as a hollow cylinder or as Flugjrotor.

With this solution, unadulterated measurement results, large transmission torques and low inertia, insensitivity to contamination and reduced maintenance costs are guaranteed. In addition, it is possible to design the measuring cell according to the invention in a relatively small size and to avoid dead space metrologically.