Professional Stormer KU Viscometer – Technical Description:

This professional Stormer-KU viscometer is a standardized Viscosity meter for determining the consistency and flow behavior of paints, coatings and related non-Newtonian materials, expressed in Cancer Units (CU). The design and measurement principle fully comply with ASTM D562 and the relevant DIN EN ISO test standards, the authoritative standard for the Krebs scale and the associated test procedure.
This precision KU viscometer is used in R&D laboratories, production environments and quality assurance systems where reproducibility, batch consistency and regulatory compliance are crucial.

1. Measurement principle

This Precision Stormer Viscometer works according to Constant torque/variable speed principle:

• A precision-manufactured Paddle rotor (KU spindle) is immersed in the coating sample.
• The device applies a constant drive torque.
• The rotational speed reached at this moment is measured.
• The rotational speed is converted into:

           i) Cancer Units (CU) – primary expenditure scale

           ii) Gram (g) – load to maintain rotation

           iii) Centipoise (cP) – approximate viscosity value for guidance

• Since the torque is constant, this precision Stormer viscometer directly maps the deformation resistance of the material – particularly relevant for shear-thinning, non-Newtonian coatings.

2. Materials and systems for KU measurement

This Precision Stormer KU Viscometer It is specifically designed for architectural and industrial coatings with non-Newtonian behavior at low shear rates. Typical applications:

• Dispersion paints (interior/exterior)
• Water-based coatings
• Acrylate emulsions
• Alkyd resin paints
• Primers and base coats
• Paints and sealants
• Printing inks (selected systems)
• Binders and intermediates

These materials require precise viscosity control to ensure:

• good spreadability and rollability
• even application
• stable stance
• defined course and leveling behavior
• reproducible layer structure

The KU scale is optimized for these properties and correlates well with practical application behavior.

3. Use in production and quality assurance

In manufacturing, this precision KU viscometer is used for:

a. Batch control

Each batch is compared to a defined target range for KU (knowledge value). Deviations indicate:

• incorrect pigment-volume ratio
• incorrect binder content
• solvent imbalance
• incomplete dispersion

b. Monitoring of raw material variability

Changes in:

• Resin viscosity
• Wetting agent effect
• Thickener efficiency

are quickly detected.

c. Control of dilution and adjustment processes

Water or solvent additions are specifically adjusted to achieve the target KU value.

d. Support for process adjustments

Viscosity trends provide clues about:

• Temperature influences
• Scher history
• Polymer hydration
• Activation of thickeners

e. Documentation for customers and authorities

Many specifications require a viscosity value in KU.

4. Device configuration and operating conditions

Proper application includes:

Sample preparation

• Homogenize the sample without introducing air.
• Conditioning to 23 ± 2 °C (unless otherwise specified)
• Ensure sufficient sample depth for complete immersion of the KU spindle.

Device settings

• Level the device precisely
• Clean and correctly assemble the spindle
• Test free rotation without mechanical friction

Measurement procedure

• Immerse KU spindle to reference depth
• Start the device and wait for stabilization.
• Record KU, g, and cP values in steady state

Calibration and verification

Although this professional Stormer viscometer does not require frequent calibration, good laboratory practice includes:

• regular verification with certified KU calibration oils
• Dimensional control of the KU spindle and the stainless steel sample cup
• Testing the drive mechanism for wear

5. Interpretation of the results

The KU values provide a functional viscosity index:

• 40–60 KU → low-viscosity, high-flow coatings
• 60–80 KU → Standard dispersion paints
• 80–110 KU → high-strength or high-build systems

Since the Cancer Scale Since the system is non-linear, small changes in KU can mean significant differences in flow behavior.

6. Advantages of the Stormer KU method and this precision KU viscometer

• High reproducibility with non-Newtonian materials
• direct correlation to practical application behavior
• Easy to use, ideal for production environments
• standardized procedure (ASTM D562) for laboratory comparability
• low sensitivity to operator influence compared to dispensing cups

These features make this professional Krebs-Stormer viscometer a key instrument in the coating industry.