Gebra STAV-II Powder Density Analyzer with Calibration Cylinders

Overview

The Gebra STAV-II Powder Density Analyzer is a precision-engineered instrument designed for the standardized determination of tapped density (also known as settled or consolidated density) of free-flowing powdered materials—particularly infant formula, milk powder, whey protein isolates, and other dairy-based powders. It operates on the principle of controlled mechanical tapping, in strict accordance with ASTM D6393 “Standard Test Method for Flowability of Powders Using the Compressibility Index and Hausner Ratio” and ISO 787-11 “Pigments and extenders — General methods of test — Part 11: Determination of apparent density after tapping”. The system delivers reproducible consolidation by applying vertical, sinusoidal motion to a calibrated cylindrical tube containing a known mass of sample. This method eliminates operator-dependent variability inherent in manual tapping protocols and ensures metrological consistency across QC laboratories, R&D facilities, and contract testing organizations serving the global dairy and nutritional supplement industries.

Key Features

• Fully automatic tapping mechanism with digitally stabilized frequency control (250 ±15 taps/min) and precisely regulated amplitude (3.0 ±0.1 mm), ensuring compliance with international standard test conditions.
• Modular volumetric cylinder system: Interchangeable high-contrast white acrylic cylinders (50, 100, 250, 500, and 1000 mL) calibrated per DIN 53194 for volumetric accuracy and thermal stability.
• Integrated five-digit programmable counter with LED display, enabling precise batch tracking and repeatable test sequencing without external logging.
• Ergonomic red-anodized control panel with illuminated power switch, tactile feedback controls, and status indicators for real-time operational verification.
• Robust cast-aluminum base and vibration-damped support structure minimizing energy loss and cross-axis resonance during tapping cycles.
• Conical locking collar design secures each cylinder concentrically and vertically, eliminating tilt-induced volume errors during consolidation.
• Low-noise brushless DC motor drive system engineered for continuous-duty operation and long-term torque stability.

Sample Compatibility & Compliance

The STAV-II accommodates a broad range of dry, granular, and agglomerated dairy powders—including non-fat dry milk (NFDM), skim milk powder (SMP), whole milk powder (WMP), lactose monohydrate, caseinates, and fortified infant formula blends. Its cylinder geometry and tapping parameters are optimized for particle size distributions typical of spray-dried dairy products (D₅₀ ≈ 100–200 µm). All measurements adhere to GLP-compliant documentation practices when paired with laboratory notebooks or LIMS-integrated reporting. Instrument performance is validated using NIST-traceable density reference materials and verified annually per ISO/IEC 17025 requirements. The analyzer supports audit-ready operation under FDA 21 CFR Part 11 when used with compliant electronic record systems.

Software & Data Management

While the STAV-II operates as a standalone hardware platform, its digital counter output and consistent mechanical behavior enable seamless integration into automated data capture workflows. Users may log results manually into validated Excel templates or connect the counter’s TTL pulse output to PLCs, SCADA systems, or custom LabVIEW applications for real-time data aggregation. For full regulatory compliance, we recommend pairing the STAV-II with a 21 CFR Part 11–compliant electronic lab notebook (ELN) that captures operator ID, timestamp, cylinder ID, initial/final mass, tapped volume, and calculated density (g/mL) with immutable audit trails. Raw data export (CSV) and trend charting are supported via third-party QA software packages commonly deployed in GMP-certified dairy manufacturing sites.

Applications

• Quality control of bulk milk powder shipments against contractual density specifications (e.g., ≥0.48 g/mL for SMP).
• Process validation of spray dryer settings—correlating outlet temperature, atomization pressure, and tapped density to optimize flowability and reconstitution behavior.
• Stability assessment of fortified formulas during accelerated shelf-life studies, where density shifts indicate caking or moisture migration.
• Raw material qualification of lactose or mineral premixes prior to blending, ensuring consistent volumetric dosing in high-speed filling lines.
• Supporting USP & Ph. Eur. monographs requiring tapped density as a critical quality attribute (CQA) for oral nutritional supplements.
• Research into powder rheology—serving as input data for Hausner ratio and compressibility index calculations essential to hopper design and pneumatic conveying modeling.

FAQ

What standards does the STAV-II comply with?
ASTM D6393, ISO 787-11, DIN 53194, and ISO/IEC 17025 for measurement uncertainty and calibration traceability.
Can the STAV-II be used for non-dairy powders?
Yes—provided the material exhibits free-flowing characteristics and falls within the recommended particle size and cohesivity range; validation per ASTM D6393 is required for non-dairy applications.
Is cylinder calibration certificate included?
Each cylinder is supplied with a manufacturer’s calibration statement referencing DIN 53194; full ISO/IEC 17025-accredited calibration certificates are available upon request.
How often does the instrument require maintenance?
Annual verification of tap frequency, amplitude, and counter accuracy is recommended; no routine lubrication or alignment is required due to solid-state actuation design.
Does the STAV-II meet FDA 21 CFR Part 11 requirements?
The device itself is not electronic record–capable, but it is fully compatible with Part 11–compliant data acquisition and ELN systems when integrated into a validated workflow.