KEM DA-860 / DA-850 / DA-840 Digital Oscillating U-Tube Density Meter

Overview

The KEM DA-860, DA-850, and DA-840 Digital Oscillating U-Tube Density Meters are precision laboratory instruments engineered for high-accuracy density and specific gravity determination of liquid samples. Based on the fundamental physical principle of oscillating U-tube metrology—where the resonant frequency of a precisely machined, evacuated U-shaped glass tube filled with sample correlates directly to its mass density—the series delivers traceable, SI-aligned measurements compliant with international standards including ISO 12058, ASTM D4052, and IUPAC recommendations. Each model employs a temperature-controlled Peltier element for active thermal regulation across the full 0–100 °C range, ensuring strict isothermal conditions critical for thermodynamic consistency in density reporting. The DA-860 achieves the highest metrological performance in the series, with a certified accuracy of ±0.000003 g/cm³ and temperature resolution of 0.001 °C—making it suitable for reference-laboratory applications requiring primary-standard-grade data. All units operate under controlled mechanical vibration isolation and are calibrated using NIST-traceable certified density standards supplied by KEM, a globally recognized manufacturer of metrological reference materials.

Key Features

• U-tube oscillation principle with real-time frequency analysis and automatic damping compensation for enhanced stability
• Integrated high-resolution camera module enabling live visualization of sample filling, bubble detection, and meniscus positioning—images stored with metadata for auditability
• Modular control architecture: supports local operation via optional tablet interface or remote management via PC-based software; multiple measurement units can be synchronized and monitored from a single workstation
• Adaptive convergence algorithm reduces stabilization time to ≤10 seconds while maintaining four-digit repeatability (e.g., <±0.000001 g/cm³ for DA-860)
• Peltier-driven temperature control with closed-loop feedback ensures uniform thermal distribution and minimizes gradient-induced drift
• Low-volume sampling capability (1–2 mL) compatible with syringe injection or automated peristaltic pump modules—reducing reagent consumption and cross-contamination risk
• Rugged benchtop design (19 kg, aluminum alloy chassis) with EMI-shielded electronics and CE/FCC-compliant electromagnetic compatibility

Sample Compatibility & Compliance

The DA-series accommodates a broad spectrum of industrial and regulatory liquid matrices—including aqueous solutions, organic solvents, petroleum fractions, electrolytes (e.g., LiPF₆ in carbonate blends), food-grade syrups, pharmaceutical excipients, cosmetic emulsions, battery electrolytes, and ultra-pure chemicals such as electronic-grade phosphoric acid and hydrogen peroxide. It meets or exceeds requirements stipulated in over 30 national and international test methods, including GB/T 29617–2013 (density, relative density, and API gravity), GB 5009.2–2024 (food relative density), GB 5009.225–2023 (ethanol concentration in alcoholic beverages), SH/T 0604–2000 (crude oil), USP (specific gravity), and ASTM D7777–22 (density of transparent and opaque liquids). Instrument validation protocols align with GLP and GMP frameworks, supporting 21 CFR Part 11-compliant electronic records when used with KEM’s validated software suite.

Software & Data Management

KEM’s proprietary Density Manager software provides comprehensive instrument control, method configuration, calibration management, and raw-data export (CSV, PDF, XML). It supports user-defined calculation templates—for example, direct conversion of density to ethanol % v/v, API gravity, or mass fraction—using embedded thermodynamic equations compliant with ISO 91-1 and ASTM D1250. Audit trails log all operator actions, parameter changes, and calibration events with timestamps and user IDs. Data integrity safeguards include password-protected access levels, electronic signatures, and immutable archive storage. Export formats are compatible with LIMS integration (via ASTM E1384 or HL7 messaging), and raw oscillation frequency/time-series datasets can be retrieved for advanced uncertainty analysis per GUM (JCGM 100:2018).

Applications

• Quality control of bulk chemicals and fine intermediates in contract manufacturing organizations (CMOs)
• Density-based concentration monitoring of battery electrolyte formulations during R&D and production release
• Verification of alcohol content and purity in spirits, wine, and fuel ethanol per OIML R 22
• Stability assessment of colloidal dispersions and nanofluids through density drift tracking over time
• Raw material identity testing in pharmaceutical manufacturing (e.g., verification of glycerin, propylene glycol, or polysorbate grades)
• Regulatory submission support for food contact materials, cosmetics, and agrochemicals under EFSA, FDA, and MHLW guidelines
• Calibration of hydrometers and pycnometers in metrology laboratories accredited to ISO/IEC 17025

FAQ

What is the difference between DA-860, DA-850, and DA-840 models?

The distinction lies in metrological performance: DA-860 offers the highest accuracy (±0.000003 g/cm³), finest temperature resolution (0.001 °C), and best repeatability (±0.000001 g/cm³); DA-850 and DA-840 provide tiered specifications optimized for routine QC and general-purpose labs.
Is the instrument compliant with 21 CFR Part 11 for regulated environments?

Yes—when operated with validated Densify Manager software and configured with role-based access controls, electronic signatures, and audit trail logging, the system satisfies electronic record and signature requirements.
Can the DA-series measure viscous or volatile samples?

It supports viscosities up to 200 mPa·s (with optional low-flow pump); highly volatile samples require temperature-controlled sample handling and rapid injection to minimize evaporation artifacts.
How is calibration traceability maintained?

KEM supplies certified density standards (e.g., aqueous NaCl solutions, n-decane, and toluene) with NIST-traceable certificates; internal calibration routines verify zero-point and span stability daily or per batch.
Does the system support unattended operation?

Yes—integrated autosamplers (optional) and scheduler functions enable overnight sequence runs with automatic cleaning cycles and pass/fail decision logic based on user-defined tolerance bands.