The operator must be careful when installing or unloading the rotor. All viscometers can measure extremely small torques due to the rotation of the rotor within the sample fluid. This requires that the friction inside the instrument be kept at a minimum. The instrument is supported by a pivot system and a gemstone bearing system, with almost no friction, as shown on the right. The support mechanism is in the pivot cup just above the position where the rotor is installed.

When the rotor is installed or unloaded, any downward force or lateral movement will cause great wear to the support system.
When you tighten or loosen the rotor, the correct way to install and unload the rotor is to gently lift the nut at the rotor and then lift it firmly. Also remember that the rotor is fixed from the opposite direction of the thread (left hand).
Similar to the precautions described above can ensure that your viscometer or rheometer can provide reliable service for a long time.
Vibration check, there is a quick check to determine the pivot point of your instrument and the status of the gem support system, you can follow the following steps:
1, do not install the rotor in the case, to ensure that the instrument zero scale in the reading window.
2, observe the red pointer just stopped at the zero indicator line.
3. Lift the nut at the rotor and rotate until the indicator reaches + 20%.
4, put down the nut at the rotor and let go, observe the red pointer until the vibration stops. Record the approximate number of vibrations and the time of vibration.
5, red pointer at this time should still stop at the zero indicator line mark. If not stopped at zero, indicating that the instrument's support system has been a certain damage. Continue to repeat the calibration procedure, if the calibration check falls outside the allowable range, call the local office or call the manufacturer directly to tell you the results and get the service for your instrument.