A viscosity and density meter with a magnetically suspended rotor

A device for measuring the viscosity and density of liquids is presented. It is a Couette-type viscometer that uses a submerged rotor to measure the viscosity without errors originating in the contact of the rotor with the sample/air boundary. The inner cylinder is a glass rotor suspended in the liquid, and the outer cylinder is also made of glass. The rotor is stabilized on the axis of the outer cylinder by an electromagnetic force controlled by feedback from the rotor’s vertical position. In the lower part of the rotor is an aluminum cylinder located in a magnetic field generated by rotating permanent magnets. The interaction of this rotating magnetic field with eddy currents generated in the aluminum cylinder causes rotation of the rotor. This rotation is optically detected, and viscosity is calculated from the measured angular velocity of rotor. The density of the liquid is calculated from the applied vertical equilibrating force. A computer controls the whole measurement. The device works at constant...

[1]  Z. Tomori,et al.  Effect of ionic strength on the interfacial properties of cytochrome c. , 1999, Biochimica et biophysica acta.

[2]  J. Beams,et al.  Magnetic Densimeter‐Viscometer , 1971 .

[3]  R. Brust,et al.  A magnetic viscometer for shear-sensitive macromolecules. , 1984, Journal of biochemical and biophysical methods.

[4]  D M Crothers,et al.  SIMPLIFIED ROTATING CYLINDER VISCOMETER FOR DNA. , 1962, Proceedings of the National Academy of Sciences of the United States of America.

[5]  E. Dickinson,et al.  Surface shear viscometry as a probe of protein-protein interactions in mixed milk protein films adsorbed at the oil-water interface. , 1990, International journal of biological macromolecules.

[6]  R Abagyan,et al.  The hydration of globular proteins as derived from volume and compressibility measurements: cross correlating thermodynamic and structural data. , 1996, Journal of molecular biology.

[7]  W. Wagner,et al.  An Absolute Viscometer-Densimeter and Measurements of the Viscosity of Nitrogen, Methane, Helium, Neon, Argon, and Krypton over a Wide Range of Density and Temperature , 2002 .

[8]  S. Harding,et al.  The intrinsic viscosity of biological macromolecules. Progress in measurement, interpretation and application to structure in dilute solution. , 1997, Progress in biophysics and molecular biology.

[9]  D. Thompson,et al.  A rotating cartesian-diver viscometer. , 1967, Proceedings of the National Academy of Sciences of the United States of America.