Rotational Tapered Bearing Simulator (TBS) viscometer – High Temperature High Shear (HTHS) method of choice

Developed in 1979 by Mr. Ted Selby of Savant Inc., and under multiple patents, the rotational TBS Viscometer became the world’s first commercial high shear viscometer for measuring viscosities of automotive engine oils and fluids under High Temperature, High Shear (HTHS) conditions.  Today, the TBS (Tapered Bearing Simulator) remains the modern benchmark ‘referee’ instrument method for HTHS viscometry due to its innovative precision measuring technique, robust design, and notable operational features and is exclusively available through Tannas Co.

The coaxial tapered Rotor/Stator Set design permits the exact measurement of rotor position and the torque response of the liquid’s resistance to flow (viscous friction), which determines the apparent fluid viscosity.  Applying a constant and linear shear rate profile continually to the fluid makes the TBS an absolute viscometer where ‘true’ shear rate is calculated from known dimensions and speed of rotation – no need for shear rate corrections or the possibility of erroneous results due to clogged capillaries.

The TBS Viscometer is associated with several industry test methods; ASTM D4683, D6616, and CEC L-36 for HTHS viscosity at 100°C and 150°C.  The D4683 method is included in the SAE J300 Engine Oil Viscosity Classification System and the ILSAC GF series Engine Oil Specifications – the most recent being GF-6, API SP, and CK-4/FA-4 specifications.  The CEC L-36 method is utilised for HTHS measurements in the European ACEA engine oil specifications.

The two TBS models available are the long-standing TBS 2100E-F and the newly introduced TBS 3000, depending on your testing needs.  The TBS provides viscosity measurements of fresh and used oils over a broad shear rate range and temperature range (40°C to 180°C).  The TBS 3000 is a redesigned and re-innovated model providing multiple enhancements to electrical and temperature components, automation, calibrations, and oil injection features, improving the overall user experience.