I. Overview

The ZNN-D6SP Digital Display Six-Speed Rotational Viscometer is a newly designed viscometer developed by our company. This viscometer features an embedded microprocessor design, a built-in high-precision angle sensor, and a stepper motor drive for smoother and more precise rotation speeds. Touchscreen operation is more intuitive and less prone to damage. The touchscreen displays the viscosity value of the test liquid and the stirring speed in real time.

This product can be widely used in petroleum, chemical, food, pharmaceutical, cosmetics industries, and research institutions.

Working principle brief: Place the slurry cup containing the test liquid on the tray, allowing the test liquid to enter the annular space (shear gap) formed between the outer sleeve of the viscometer and the rotor. When the stepper motor drives the outer sleeve to rotate, the sleeve experiences viscous resistance in the test liquid, generating a reactive force. This force transmits torque to the rotor in the sleeve through the test liquid in the annular space. The rotor is connected to a set of dial components. When the torque and viscous resistance reach equilibrium, the dial assembly stabilizes at a certain scale value. Since the scale value is proportional to the viscous resistance experienced by the sleeve, multiplying this scale value by a specific coefficient yields the final viscosity value, which is displayed on the LCD screen for reading.

The shear rate and viscosity value have a linear correspondence, meaning the relationship between shear stress and shear rate is represented as a straight line. In practical applications, many fluids may not strictly follow Newton's law, but if their rheology is relatively close to Newtonian behavior, the viscometer can still be used for measurement, and the obtained viscosity values are relatively accurate. ZNN-D6SP Digital Display Six-Speed Rotational Viscometer is calibrated in Newtonian mode with linear calibration and is not suitable for test samples that do not conform to Newtonian linear calculation methods. In such cases, viscosity measurement and speed calculation should use nonlinear calculation methods.

When the outer sleeve, rotor, and torsion spring operate at a rate of 300 rpm, the measurement unit of the viscometer is centipoise (or millipascal-second). Data measured at other speeds require a series of multiplicative conversions. Part VI of this document provides the viscosity calculation method for pseudoplastic fluids (such as drilling fluids).

When selecting different rotation speeds or using different torsion spring-rotor combinations, the selectable range of shear rates may change. To broaden the range of shear stress and measure more types of liquids, different torsion springs can be replaced.

II. Model and Specifications

III. Main Technical Parameters of the Instrument