Anton Paar DMA35 Portable Oscillating U-Tube Density Meter

Overview

The Anton Paar DMA35 is a field-deployable, battery-powered oscillating U-tube density meter engineered for high-precision liquid density and concentration measurements under non-laboratory conditions. Based on the fundamental physical principle of resonant frequency shift in a vibrating U-shaped glass tube filled with sample, the instrument determines density by measuring the period of oscillation — a method traceable to SI units and compliant with ISO 12089, ASTM D4052, and EN ISO 16750. Its robust mechanical design, combined with active bubble ejection geometry and temperature-controlled measurement cell, ensures metrological reliability comparable to benchtop laboratory densimeters — even during outdoor operation, in industrial plants, or aboard marine vessels. The DMA35 operates across a wide density range (0–3 g/cm³), accommodating aqueous solutions, hydrocarbons, alcohols, acids, and viscous liquids up to 300 mPa·s (with viscosity correction applied). With an operating ambient range of −10 to +50 °C and IP54 ingress protection, it is certified for use in dusty and splash-prone environments, including Zone 1 hazardous areas when equipped with Ex or Ex Petrol variants.

Key Features

• True portable operation: Self-contained power (3 × AA batteries), lightweight (660 g), and compact footprint (245 × 103 × 126 mm) enable handheld or tripod-mounted deployment.
• Oscillating U-tube technology with patented intelligent cell coupling (AT516421 B1 / EP3015847 B1) — enables rapid, tool-free measurement cell replacement without calibration loss.
• Integrated peristaltic sampling pump with optional extended probe (up to 1.5 m) for remote or hard-to-access sample points.
• High-resolution color display with auto-rotating orientation and glove-compatible capacitive touchscreen interface — operable in full sunlight or low-light conditions.
• Onboard viscosity correction algorithm for samples up to 300 mPa·s; automatic detection and compensation based on damping behavior during oscillation decay.
• Intrinsic safety certification (Ex II 2 G Ex ib IIC T4) for use in potentially explosive atmospheres containing gases, vapors, or mists.
• IP54-rated enclosure with splash-resistant housing and rubberized measurement cell guard for mechanical and environmental protection.

Sample Compatibility & Compliance

The DMA35 supports direct measurement of homogeneous, non-particulate liquids — including fuels, lubricants, ethanol blends, sugar syrups, battery electrolytes, pharmaceutical solvents, and food-grade brines. It complies with international regulatory frameworks governing quality assurance and data integrity: measurement data includes timestamp, user ID, method parameters, and environmental metadata — supporting GLP/GMP audit trails. Firmware implements secure RFID-based sample identification and Bluetooth-enabled wireless transfer to LIMS or ERP systems, aligning with FDA 21 CFR Part 11 requirements for electronic records where configured with appropriate IT infrastructure. All density values are traceable to NIST-certified reference standards via factory calibration reports (available optionally with ISO/IEC 17025-accredited calibration service).

Software & Data Management

Internal memory stores up to 1024 complete measurement records, each containing density, temperature, viscosity-corrected value, method name, operator ID, and RFID-tagged sample identifier. Up to 30 user-defined measurement methods can be configured — including custom unit conversions (e.g., °Brix, % alcohol by volume, API gravity, H₂SO₄ concentration, specific gravity) and pass/fail tolerance limits with audible/visual alerts. Data export is supported via Bluetooth to Android/iOS devices running the free Anton Paar Mobile app or to Windows PCs using the optional Bluetooth USB adapter. Raw ASCII output (CSV-compatible) includes all metadata fields required for statistical process control (SPC) and trending analysis. No proprietary drivers or cloud dependencies are required for basic data retrieval.

Applications

• Field verification of fuel blending ratios (e.g., biodiesel-diesel mixtures, ethanol-gasoline E10/E85) per ASTM D7467 and EN 14214.
• Real-time monitoring of battery electrolyte density in lead-acid battery maintenance (20–30% H₂SO₄).
• On-site quality control of alcoholic beverages, soft drinks, and fruit juices using °Brix or alcohol concentration tables.
• Process support in chemical manufacturing for reaction mixture density tracking and endpoint determination.
• Marine bunkering operations — rapid density checks prior to fuel delivery to ensure compliance with ISO 8217 specifications.
• Pharmaceutical excipient verification and cleaning validation solution concentration checks.

FAQ

What is the maximum allowable sample viscosity for accurate measurement?
The DMA35 provides fully compensated results for liquids up to 300 mPa·s at measurement temperature; viscosity correction is applied automatically based on damping characteristics observed during oscillation decay.
Can the instrument measure hot samples directly?
Yes — the integrated sample inlet accepts liquids up to 100 °C; however, the internal measurement cell maintains temperature control only between 0–40 °C, so thermally equilibrated readings require either pre-cooling or use of the optional Peltier-cooled version (DMA35 Peltier).
How is measurement traceability ensured?
Each unit ships with a factory calibration certificate referencing NIST-traceable density standards; optional ISO/IEC 17025-accredited recalibration services include uncertainty budgets and full compliance documentation.
Is RFID functionality mandatory for routine operation?
No — RFID is optional for sample identification; manual entry or barcode scanning (via external Bluetooth scanner) remains fully supported.
What happens if the measurement cell breaks?
The patented smart cell coupling allows immediate replacement of the U-tube cell without recalibration or disassembly tools — maintaining measurement continuity and minimizing downtime.