Instructions for Use of Rotary Viscometer

1. The performance index of the instrument must meet the requirements of national metrological verification regulations. The instruments in use shall be subject to periodic verification. If necessary, intermediate self inspection shall be conducted to determine that their metering performance is qualified and the coefficient error is within the allowable range, otherwise accurate data cannot be obtained.2. Pay special attention to the temperature of the measured liquid. Pay special attention to keep the temperature of the measured liquid near the specified temperature point, and do not exceed 0.1 for measurement.3. Selection of measuring containers. For the double cylinder rotary viscometer, carefully read the instrument manual, and different rotors match the corresponding outer cylinder, otherwise the measurement results will have huge deviation. For a single cylinder rotary viscometer, the radius of the outer cylinder is required to be infinite in principle. In actual measurement, the inner diameter of the measuring container is required to be no less than a certain size.

4. Correctly select the rotor or adjust the speed to make the indication between 20 90 grids. If the indication is above 90 grids, the torque generated by the hairspring is too large, which is easy to creep and damage the hairspring. Therefore, the rotor and speed must be selected correctly.5. Frequency correction. The correction formula is that the actual viscosity is equal to the indicated viscosity multiplied by the nominal frequency divided by the actual frequency.

6. The depth of rotor immersed in liquid and the influence of bubbles. The rotary viscometer has strict requirements on the depth of the rotor immersed in liquid, and must be operated in accordance with the instructions. There are often bubbles when the rotor is immersed in liquid. Most of them will float up and disappear after the rotor rotates for a period of time. Sometimes the bubbles attached to the lower part of the rotor can not be eliminated. The existence of bubbles will bring great deviation to the measurement data. Therefore, it is an effective method to dip the rotor slowly and obliquely.