Rotational viscometer for high-pressure high-temperature fluids

Patent · Tue Jan 01 04:00:00 EST 1985

OSTI ID:865336

Carr, Kenneth R ^[1]

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1. Knoxville, TN

The invention is a novel rotational viscometer which is well adapted for use with fluids at high temperatures and/or pressures. In one embodiment, the viscometer includes a substantially non-magnetic tube having a closed end and having an open end in communication with a fluid whose viscosity is to be determined. An annular drive magnet is mounted for rotation about the tube. The tube encompasses and supports a rotatable shaft assembly which carries a rotor, or bob, for insertion in the fluid. Affixed to the shaft are (a) a second magnet which is magnetically coupled to the drive magnet and (b) a third magnet. In a typical operation, the drive magnet is rotated to turn the shaft assembly while the shaft rotor is immersed in the fluid. The viscous drag on the rotor causes the shaft assembly to lag the rotation of the drive magnet by an amount which is a function of the amount of viscous drag. A first magnetic pickup generates a waveform whose phase is a function of the angular position of the drive magnet. A second magnetic pickup generates a waveform whose phase is a function of the angular position of the third magnet. An output is generated indicative of the phase difference between the two waveforms.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN
• DOE Contract Number: W-7405-ENG-26
• Assignee: United States of America as represented by United States (Washington, DC)
• Patent Number(s): US 4499753
• OSTI ID: 865336
• Country of Publication: United States
• Language: English

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