In the viscosity test experiment, there is often a situation that the viscosity range of the unknown sample needs to be measured. How does the DV-79 digital viscometer correctly measure the viscosity value of the sample in the unknown viscosity range. The specific operation method is as follows:
(1) General principles of measurement: for high-viscosity samples, use small-volume (No. G, F) rotors and slow speeds; for low-viscosity samples, choose large-volume (No. E, F) rotors and fast speeds. The percentage scale (torque) of each measurement is a normal value between 10% and 90%, and the viscosity value measured within this range is the correct value.
(2) First roughly estimate the viscosity range of the sample to be tested, and then select a small-volume rotor and a slow speed for high-viscosity samples, and a large-volume rotor and fast speed for low-viscosity samples. Generally, the rotor is selected first, and then the appropriate speed is selected. For example, when the rotor SP is E, the speed is 750RPM, and the screen directly displays the full scale as 100mPa.s. When the speed is changed to 75RPM, the full scale is 1000mPa.s.
(3) When the approximate viscosity of the sample to be tested cannot be estimated, it should be set to a higher viscosity first. Experiment with small to large rotors and slow to fast speeds. Then judge the rationality of the selection of the rotor and speed according to the percentage meter scale (torque) for each measurement. The percentage meter scale must be between 10% and 90% as a normal value. An alarm will sound to prompt the user to change the speed and rotor. Don't forget that if you change the rotor, you must change the rotor number SP according to the selected rotor.
Out of measurement range
When the current speed and the current rotor measurement range are exceeded, the screen will display, and a beeping alarm will sound at the same time. When the torque exceeds 100%, the percentage reading and viscosity reading are all EEEE.
