Viscosity: Simply put, it’s the thickness or internal friction of a fluid. Water has low viscosity, while honey has high viscosity.
Newtonian Fluids: These fluids have a constant viscosity regardless of the shear rate applied (e.g., water, oils, simple solvents). Their viscosity mainly depends on temperature.
Non-Newtonian Fluids: Their viscosity changes depending on the applied shear rate or stress (e.g., ketchup, paint, polymers, slurries). Some become thinner with shearing (shear-thinning), while others thicken (shear-thickening). Some also exhibit time-dependent behavior (thixotropy).
Knowing whether your sample is Newtonian or non-Newtonian is crucial, as it influences the type of viscometer and testing parameters needed.
Viscosity Range: What is the expected minimum and maximum viscosity of your samples (measured in mPa·s or cP)? Ensure the viscometer’s measurement range covers your needs. HINOTEK models offer different ranges (e.g., RV-SSR-H up to 4M mPa·s, HB-SSR-H up to 16M mPa·s, with optional rotors extending ranges).
Sample Type & Characteristics: Are you measuring liquids, pastes, slurries, or gels? Consider particle size, potential for settling, or chemical compatibility (requiring specific materials like stainless steel).
Sample Volume: How much sample do you typically have available for testing? Some techniques require larger volumes, while others, like HINOTEK’s high-temperature models using small sample adapters, need only 15-20 ml.
Temperature Requirements: Viscosity is highly temperature-dependent. Do you need to measure at ambient temperature, or control it precisely at specific elevated temperatures? HINOTEK offers models with standard heating baths and high-temperature options (e.g., up to 250°C or even 300°C). Accurate temperature control (like ±0.1°C in some HINOTEK models) is vital.
Shear Rate Requirements: For non-Newtonian fluids, understanding behavior at different shear rates is often necessary. Rotational viscometers, like those offered by HINOTEK, allow testing at various speeds (shear rates). HINOTEK models like RV-SSR-H and HB-SSR-H offer multiple speed settings (e.g., 18 speeds).
Accuracy and Repeatability: What level of precision do you require? Check the manufacturer’s specifications for accuracy (e.g., ±3% for Newtonian liquids in HINOTEK high-temp models) and repeatability (e.g., ±1.5%).
Ease of Use and Cleaning: Consider the user interface (HINOTEK models feature LCD displays showing direct readings), setup time, and how easy the instrument is to clean between samples, especially if testing different materials.
Data Output & Connectivity: Do you need to print results or connect to a PC? Some HINOTEK models offer RS232 interfaces for direct connection to printers or computers (optional software may be available for rheological curves).
Application Goal: Are you performing routine quality control (QC) checks or more in-depth research and development (R&D) requiring detailed characterization?
Digital Display: Clear LCD screens show viscosity readings directly, eliminating manual calculations.
Rotational Principle: Utilizes spindles rotating within the sample to measure resistance to flow.
Multiple Speeds: Allows testing across different shear rates, essential for characterizing non-Newtonian fluids.
Ease of Operation: Designed for user-friendly setup and measurement.
High-Temperature Options: Models like the RV-SSR-H (NDJ-1C), HA-SSR-H, and HB-SSR-H (NDJ-1F) are specifically designed for high-temperature applications (up to 250°C or 300°C) using small sample adapters and precise temperature control.
Timing Function: Useful for non-Newtonian fluids where measurement duration affects results.
General Rule: Lower viscosity fluids typically require larger spindles or higher speeds, while higher viscosity fluids need smaller spindles or lower speeds.
Target Range: Aim for a spindle/speed combination that gives a torque reading within the optimal range recommended by the manufacturer (often between 10% and 90-100% of the full-scale range) for best accuracy.
HINOTEK Spindles: High-temperature models typically come with standard spindles (e.g., #21, #27, #28, #29). An optional #0 rotor is often available to measure lower viscosity ranges. Refer to the specific model’s manual for guidance on spindle selection based on the expected viscosity range.
Define Your Needs: Clearly list your requirements based on the factors discussed above (viscosity range, sample type, temperature, volume, accuracy, etc.).
Review HINOTEK Models: Compare the specifications of different HINOTEK digital viscometers available on their website or in catalogs against your requirements. Pay attention to measurement ranges, temperature capabilities, and included accessories.
Consider High-Temperature Needs: If your application involves hot melts, asphalt, waxes, or other high-temperature materials, focus on models like the RV-SSR-H, HA-SSR-H, or HB-SSR-H.
Consult with Experts: Don’t hesitate to contact HINOTEK or an authorized distributor. Provide them with your application details, and they can offer specific model recommendations and advice on appropriate configurations (including spindles).
Conclusion
Choosing the right viscometer is a crucial step towards obtaining reliable and meaningful viscosity data. By carefully considering your sample characteristics, testing conditions, and application goals, and understanding the features offered by HINOTEK’s range of digital rotational viscometers, you can select an instrument that provides accurate results and enhances your laboratory’s capabilities. Always refer to the specific product documentation and consult with HINOTEK experts when making your final selection.