1957: First vibration viscometer V-1201 developed.
1960: Viscotester V-1207 developed and released to the market.
This product features a rotor which is held into a liquid and rotated. The viscous resistance (torque) of the liquid acting on the rotor is used to measure the viscosity. Measurement reproducibility was excellent and handling was easy, but the complex structure of the product resulted in a high price.
1965: VT-01 for normal viscosity and VT-02 for high viscosity released.
An improvement of the VT-1207 mechanism made it possible to offer the product at a lower price point, while maintaining advantages such as high accuracy, stable performance, and good measurement reproducibility. The small size and light weight of the viscotesters facilitated on-site measurements and resulted in enhanced ease of use.
Subsequent developments include the further improved models VT-03/VT-04 and VT-03F/04F.
2013: The Viscotester VT-06 with LCD panel is released. This model continues to be available today.