Gardco EZ2 and EZ3 Zahn-Type Viscosity Cups

Overview

The Gardco EZ2 and EZ3 Zahn-type efflux viscosity cups are precision-manufactured stainless steel flow cups designed for rapid, field- or lab-based kinematic viscosity assessment of low-to-medium viscosity Newtonian and near-Newtonian liquids. Based on the principle of gravitational efflux time measurement—where viscosity is inversely proportional to the time required for a fixed volume of liquid to drain through a calibrated orifice—the EZ series adheres strictly to standardized test methods including ASTM D1200, ISO 2431, and DIN 53211. These cups operate under controlled ambient conditions (typically 25 °C ± 0.5 °C), requiring no external power or calibration fluids. Their robust one-piece construction eliminates internal seams or welds, ensuring long-term dimensional stability and resistance to solvent corrosion—critical for repeatable inter-laboratory comparisons in QC environments across coatings, inks, adhesives, and resin manufacturing.

Key Features

• High-precision machined orifice: Each cup features a laser-drilled, polished stainless steel orifice with traceable dimensional certification per NIST-traceable metrology protocols.
• Two standardized models: EZ2 (for viscosity range ~20–150 cSt) and EZ3 (for ~70–600 cSt), enabling coverage across common industrial fluid specifications without interpolation error.
• Ergonomic handle design with integrated suspension hook: Facilitates consistent vertical orientation during efflux timing and minimizes operator-induced tilt errors.
• Non-porous, passivated 316 stainless steel body: Resists pitting and surface adsorption, ensuring cleaning integrity between samples and eliminating carryover risk.
• No moving parts or electronics: Eliminates drift, recalibration cycles, or firmware dependencies—ideal for audit-ready GLP/GMP workflows where instrument qualification is simplified.

Sample Compatibility & Compliance

The EZ2 and EZ3 cups are validated for use with clear, particle-free, low-sediment Newtonian liquids such as solvent-borne alkyds, acrylic dispersions, UV-curable monomers, and mineral spirits-based thinners. They are not suitable for non-Newtonian, thixotropic, or highly viscous materials (>600 cSt), nor for suspensions containing particles >10 µm. All units ship with a certificate of conformance referencing ASTM D1200 Annex A1 and ISO 2431 Clause 6.2. For regulated environments—including FDA-regulated pharmaceutical excipient testing or automotive OEM coating release—these cups support documented method validation when used within defined temperature control, stopwatch accuracy (±0.1 s), and operator training protocols compliant with ISO/IEC 17025.

Software & Data Management

As purely mechanical efflux devices, the EZ2/EZ3 cups require no embedded software, drivers, or connectivity. However, they integrate seamlessly into digital quality management systems via manual entry or barcode-scanned test records. When paired with compliant timing devices (e.g., ISO 9241-110 validated digital stopwatches), data capture aligns with 21 CFR Part 11 requirements for electronic records—provided audit trails, user authentication, and version-controlled SOPs govern the recording process. Gardco provides printable calibration check logs and ASTM-compliant reporting templates compatible with LIMS platforms such as LabWare and Thermo Fisher SampleManager.

Applications

• Coatings QC: Batch release verification of viscosity prior to spray application or dip-coating processes.
• Ink formulation labs: Rapid screening of diluent adjustments during gravure or flexographic ink development.
• Adhesive manufacturing: Monitoring solvent evaporation rates in contact adhesives and laminating resins.
• Raw material incoming inspection: Verification of supplier-provided viscosity specifications for solvents and monomers.
• Educational laboratories: Teaching fundamental rheological concepts—including kinematic viscosity, efflux time correlation, and standard method execution—without instrumentation complexity.

FAQ

What is the difference between EZ2 and EZ3 cups?
The EZ2 cup has a smaller orifice diameter and is calibrated for lower-viscosity fluids (~20–150 cSt), while the EZ3 uses a larger orifice for higher-viscosity ranges (~70–600 cSt). Selection depends on expected efflux time: optimal measurements fall between 20–60 seconds per ASTM D1200.
Do these cups require annual recalibration?
No—Zahn cups are dimensionally stable passive devices. Recertification is only necessary if physical damage occurs or after aggressive abrasive cleaning. Users should verify orifice integrity annually using optical microscopy or certified gauge pins per ISO 2431 Annex B.
Can I use the EZ cup for non-aqueous solvents like xylene or acetone?
Yes—316 stainless steel construction ensures compatibility with most organic solvents. Always rinse thoroughly with a miscible intermediate solvent (e.g., isopropanol) before drying to prevent residue buildup.
Is temperature control mandatory during testing?
Yes—ASTM D1200 requires sample equilibration at 25 °C ± 0.5 °C. Viscosity varies exponentially with temperature; uncontrolled deviations >±1 °C introduce >5% measurement uncertainty.
How do I validate method equivalence between EZ cups and rotational viscometers?
Correlation studies must be performed per ASTM D1200 Section 8.3 using matrix-matched reference fluids. Direct unit conversion (cSt → mPa·s) assumes density = 1 g/cm³; for denser fluids (e.g., glycols), kinematic viscosity (cSt) × density (g/cm³) = dynamic viscosity (mPa·s).