VT-06 | Viscometer



History of RION Viscotesters

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.




The VT-06 is designed for quality control applications in the manufacturing process of industrial products such as petrochemicals, paint, and adhesives, as well as foodstuffs. Viscosity measurements covering a wide range are possible, such as gear oil used in construction machinery. Measurement is performed by simply submerging a rotor in the fluid. The resistance to rotor movement caused by the viscosity (torque) is measured to obtain direct readings.

  • Compact and light weight make the unit easily portable and allow operation with one hand
  • Can be powered by alkaline batteries, nickel-hydride rechargeable batteries, or AC adapter
  • Direct indication of viscosity in decipascal-seconds (SI units)
  • Dedicated stand for measurement available as option


Applicable standards CE marking, WEEE Directive, Chinese RoHS
Measurement range (based on combination with the cup specified below “Sample fluid capacity”)
No. 3 rotor: 0.3 dPa•s to 13 dPa•s (resolution: 0.1)
No. 1 rotor: 3 dPa•s to 150 dPa•s (resolution: 1)
No. 2 rotor: 100 dPa•s to 4000 dPa•s (resolution: 10)
Sample fluid capacity
No. 1 and No. 2 rotor Approx. 350 mL (with JIS 300 mL beaker)
No. 3 rotor Approx. 150 mL (with No. 3 cup)
Clearance between rotor end and cup bottom: about 15 mm


Measurement accuracy and reproducibility ±10% ±1 digit of indicated value
Reproducibility ±5%
* Calibrated according to JIS Z 8809:2011 standard liquids for calibrating viscometer
* The rounding error resulting from resolution occurs
Rotor speed 62.5 rpm
Max. continuous measurement time per measurement 100 s
Display value hold function Value at end of measurement is retained
Backlight function Switchable backlight
Time until auto-off: 60 s
(when rotor is not operating and unit is powered from batteries)


Auto shutdown function (when an AC adapter is not used) If rotor is not turning and no controls are operated for 5 minutes, power is automatically shut off
Resume function Last selected rotor number setting is retained during power-off
Ambient conditions for use 5°C to 35°C, 10% to 90%RH (no condensation)
Power requirements Alkaline batteries LR6, Ni-MH rechargeable batteries, or AC adapter VA-05J (5 V to 7 V : rated voltage 6 V)
Current consumption approx. 250 mA (at maximum torque)
Battery voltage check Displaying battery status (4 steps)
Dimensions 175 mm (H) × 77 mm (W) × 45 mm (D) (maximum)
175 mm (H) × 77 mm (W) × 40 mm (D)
(without protruding parts)
Weight Approx. 260 g (without batteries)


Supplied accessories
 No. 1 rotor (dia. 24 mm × 53 mm × 166 mm) SUS304 1
No. 2 rotor (dia. 15 mm × 1 mm × 113 mm) SUS304 1
No. 3 rotor (dia. 45 mm × 47 mm × 160 mm) SUS304 1
No. 3 Cup (dia. 52.6 mm × 75 mm) SUS304 1
Rotor extension (in a tube) (900 mm; 300 mm × 3) SUS304 1
IEC LR6 (size AA) battery 4
Instruction manual 1
Viscosity measurement guide 1
Inspection certificate 1
Optional accessory
AC adapter VA-05J
Stand VA-04




Controls and Functions






Technical Documents

Rotor extension
The supplied foldable rotor extension consists of three 30 cm rods joined by rings. The combined length is 90 cm. When wishing to use the extension at a length of 30 cm or 60 cm, open the connector rings with a pair of pliers, remove the desired number of elements, and rejoin the extension rods. Be sure to close the rings fully again, to prevent the extension from getting detached during use.
Attach the end with the male thread to the viscotester and the end with the female thread to the rotor.
Note that both are left-hand (reverse) screw threads, so you must turn the parts counterclockwise to screw them in.
When measuring a fluid with high viscosity, the joint will look as shown in the illustration, but this does not affect the measurement.
The rotor extension rods are made of stainless steel.
VT-06 Attaching the Rotor

  • If you do not know the viscosity of the sample fluid, perform measurement using rotors in the following order: No. 2 rotor, No. 1 rotor, No. 3 rotor.
  • Because this is a left-hand (reverse) screw thread, you must turn the rotor counterclockwise to screw it in.
  • Verify that the blue rubber section of the rotor mounting shaft is mounted correctly and that does not touch the case of the unit. Otherwise correct measurement may not be possible.
  • To detach the rotor, hold the blue rubber section of the rotor mounting shaft with your fingers and turn the rotor clockwise.


How to measure

  1. Hold the viscotester in one hand or mount it to the optional stand (VA-04). Use the level gauge on the unit to verify that the unit is approximately horizontal.
  2. Place the rotor in the center of the cup or beaker and fill in sample fluid so that it comes to about the center of the fluid mark on the rotor.
  3. Hold down the power key until the power is set to on (at least 1 second).
  4. Use the rotor selector key to select the correct rotor number.
  5. Press the START key.
    The indication “RUN” appears on the display and the rotor starts to turn. Hold the unit steady until the viscosity indication has stabilized. When a stable value has been obtained, press the START key again. The rotor stops turning, and the measurement value remains on the display for easy reading.
  6. When measurement is completed, hold down the power key until the power is set to off (at least 1 second).

* About power swing
When the rotor starts to turn, temporary overload may cause a socalled power swing condition where the rotor cannot turn properly. In such a case, the indication “FAIL” is shown on the display, the rotor is stopped, and then started up again.

Application Examples

PDF Download