The TBS measures high temperature, high shear rate (HTHS) viscosity of an oil as seen by the engine during operation.  An absolute viscometer, the TBS is required for testing passenger car engine oils specified in API SL, SM; ASTM D4485; SAE J300 Viscosity Classification; ILSAC GF-2 through GF-4; and locomotive oil specifications.  The ASTM test methods designated for standard operation of the TBS Viscometer are ASTM D4683 and D6616.  The TBS is also included in CEC L-36-A-90.

The TBS has been shown to be the most versatile, accurate and precise of all high shear viscometers on the market.  It also has been shown to closely correlate with, and predict, actual performance of engine oils in bearings.  Shear rates as low as 50,000 and as high as 7.5 x 10⁶ reciprocal seconds (sec^-1) have been measured on the TBS – making it the only commercially available, very high shear rate, broad temperature range, absolute viscometer.

An easy-to-operate, bench-top device designed to measure HTHS viscosities on a variety of fluid and lubricant types, the TBS is most widely used on engine oils and automotive transmission fluids (ATF).  As a research tool, the TBS has tested other organic and water-based fluids such as hydraulic fluids, inks, low-melting waxes and polymeric solutions with viscosities ranging from 1 to 30 centiPoise (cP).

In 1998, Tannas restructured its line of TBS Viscometers by introducing, as its new workhorse, a device freshly designed and appropriately named the TBS 2100E series Viscometer.  With a dramatically reduced footprint, state-of-the-art motor and transducer technology and many operator-friendly features, the 2100E series effectively carries Tannas well into the 21st millennium.

More recently, the TBS has been equipped with hardware and software permitting Full-Automation. Designated the TBS 2100E-F model, the Full-Auto Software Package allows for PC control of the rotor/stator relationship for automated cross-over and viscosity calibrations and output of the resultant viscosity data to a LAN or dedicated printer. With the connected AutoSampler, the PC also controls the injection of each sample and automatically injects a check-oil throughout the rack of samples to ensure proper calibration is maintained. Using the chase-flush technique originally developed by Tannas, an oil sample is injected into the viscometer in a manner completely replacing the previous sample without the need for time-consuming solvent cleaning.  With the use of a special Idling Oil, the unit can remain running indefinitely on standby without adjustment of the temperature or shear rate setting.

Depending on the temperature control source chosen, the operating temperatures of the TBS ranges from 40°C to over 200°C with close temperature control of ±0.1°C.

All previous models sold by Tannas (TBS 500, SSTBS and original TBS 2100E) have been effectively replaced by the 2100E-F model.

More information on the development and application of the TBS Viscometers can be found in technical publications or contact us.