Julabo DD-31AD Density & Specific Gravity Bath

Overview

The Julabo DD-31AD Density & Specific Gravity Bath is a precision temperature-controlled immersion bath engineered for high-accuracy density and specific gravity determinations in compliance with international standard test methods. It operates on the principle of thermal equilibrium stabilization—maintaining sample fluids (e.g., petroleum products, lubricants, alcohols, aqueous solutions) at rigorously controlled temperatures to ensure reproducible hydrometer or pycnometer measurements. Designed specifically for ASTM D1298, ASTM D1481, ISO 3675, ISO 3838, DIN 51757, JIS K2207, and IP 160–190 applications, the DD-31AD provides the thermal stability and spatial uniformity required for gravimetric density analysis where ±0.01 °C temperature control directly translates into sub-0.0001 g/cm³ measurement confidence.

Key Features

• High-precision temperature regulation: ±0.01 °C stability over the full operating range (+5 to 60 °C), achieved via PID-controlled heating, low-noise circulation pump, and optimized thermal mass design.
• Large-capacity bath chamber (25–31 L internal volume) with transparent acrylic front window for real-time visual monitoring of hydrometer immersion depth and meniscus alignment.
• Adjustable, height-calibrated sample tube holder accommodates standard and non-standard graduated cylinders (e.g., ASTM 100-mL, 200-mL, or custom-diameter vessels) with fine vertical positioning (±0.1 mm resolution).
• Dual-mode lift mechanism: manually operated rack-and-pinion or optional motorized vertical actuation for seamless integration with analytical balances during mass-at-temperature workflows.
• Stainless-steel bath interior with corrosion-resistant coating; external housing constructed from impact-resistant polymer with integrated ventilation and thermal shielding.
• Low-turbulence fluid circulation (0.23–0.45 L/min) ensures minimal convection-induced meniscus distortion while maintaining axial temperature homogeneity ≤ ±0.02 °C across the measurement zone.

Sample Compatibility & Compliance

The DD-31AD supports a broad spectrum of liquid samples used in petrochemical, pharmaceutical, food & beverage, and academic research laboratories—including crude oil fractions, biodiesel blends, ethanol-water mixtures, glycerol solutions, and calibration standards (e.g., certified water, n-decane, toluene). Its geometry and thermal performance meet the dimensional and environmental requirements specified in ASTM D70 (petroleum product density), ASTM D287 (API gravity of oils), and ISO 3675 (crude petroleum density by hydrometer). The bath’s temperature uniformity profile has been validated per ASTM E100 Annex A and DIN 12876-1 for Class II laboratory thermostats, supporting GLP-compliant documentation when paired with traceable calibration records.

Software & Data Management

While the DD-31AD operates as a standalone analog-controlled bath, its RS232/RS485 interface enables integration with laboratory information management systems (LIMS) or PC-based data acquisition platforms. Optional Julabo LabSoft software permits remote setpoint adjustment, real-time temperature logging (with timestamped CSV export), alarm event history (over-temperature, low-level, pump fault), and audit-trail generation compliant with FDA 21 CFR Part 11 requirements when deployed with electronic signature modules. All firmware updates are delivered via secure HTTPS portal and retain full backward compatibility with legacy calibration certificates.

Applications

• Determination of API gravity and density of crude oil and refined products per ASTM D1298 and IP 160.
• Quality control of ethanol fuel blends (E10, E85) using ASTM D71 and ISO 3838 protocols.
• Verification of density specifications for pharmaceutical excipients and active ingredients under USP and Ph. Eur. 2.2.39.
• Calibration of glass hydrometers, pycnometers, and digital density meters against NIST-traceable reference materials.
• Temperature-dependent density profiling of ionic liquids and nanofluids in materials science research.
• Supporting ASTM D2111 (density of halogenated hydrocarbons) and JIS K2249 (lubricating oil density) in Japanese and ASEAN regulatory testing labs.

FAQ

What temperature accuracy is guaranteed across the bath’s working volume?
The DD-31AD maintains ±0.01 °C setpoint stability at sensor location, with axial and radial uniformity ≤ ±0.02 °C in the central 10-cm³ measurement zone, verified per DIN 12876-1 Class II criteria.
Can the bath accommodate non-standard hydrometers exceeding 400 mm in length?
Yes—the vertical travel of the adjustable sample tube holder extends up to 450 mm, and the 37-cm bath depth allows full immersion of extended-scale hydrometers without modification.
Is the unit suitable for use with flammable solvents?
The DD-31AD is not intrinsically safe; it must be operated in well-ventilated areas away from ignition sources. For Class I Division 1 environments, consult Julabo’s Ex-certified bath variants (e.g., model DD-Ex series).
How is calibration traceability established?
Each unit ships with a factory calibration certificate traceable to PTB (Physikalisch-Technische Bundesanstalt) standards; optional on-site verification services include NIST-traceable RTD probe validation and ISO/IEC 17025-accredited uncertainty reporting.
Does the bath support automated data export to Excel or LIMS?
Yes—via serial interface and LabSoft software, users can configure automatic timestamped temperature logs, alarm triggers, and CSV-formatted reports compatible with common LIMS ingestion protocols.