A&D EJ-120D Density Balance

Overview

The A&D EJ-120D Density Balance is a precision laboratory instrument engineered for rapid, accurate determination of density for both solid and liquid samples using the Archimedean principle of buoyancy. Unlike conventional analytical balances requiring manual calculation or external software conversion, the EJ-120D integrates real-time density computation directly into its firmware—enabling direct digital readout in g/cm³ without operator intervention. Its dual-mode operation supports both immersion-based solid density measurement (using air and submerged weight acquisition) and liquid density measurement via calibrated reference weights and temperature-compensated fluid media. Designed for reproducibility under variable environmental conditions, the instrument features built-in temperature input capability to correct for thermal expansion effects in measurement fluids such as kerosene, ethanol, or water—minimizing systematic drift caused by ambient fluctuations. The EJ-120D conforms to fundamental metrological requirements for density testing in regulated environments and serves as a foundational tool in quality control laboratories, R&D facilities, and academic institutions where traceable, repeatable physical property data are essential.

Key Features

• Backlit high-contrast LCD display with 16 mm digit height—optimized for readability in low-light or industrial settings
• Direct density readout for solids and liquids: eliminates manual calculation and reduces transcription errors
• Digital calibration system supporting zero-point and span calibration with user-adjustable reference mass values
• On-device temperature and reference density entry for dynamic compensation of fluid density variations
• Support for multiple immersion media including kerosene, isopropyl alcohol, and other low-surface-tension liquids
• Density comparison mode with programmable HI/GO/LO limits and audible/visual alarm outputs
• Auto-power-off function with configurable idle timeout to extend battery life
• Dual power operation: AC adapter for continuous lab use; internal rechargeable battery for field or mobile applications
• GLP/GMP/GCP-compliant data output: assignable instrument ID, timestamped calibration reports, and audit-ready records

Sample Compatibility & Compliance

The EJ-120D accommodates a broad range of sample geometries and material classes—including polymers, metals, ceramics, powders, foams, and porous composites—for solid density analysis. For liquids, it supports transparent or mildly turbid fluids compatible with standard immersion techniques. All measurements adhere to the principles outlined in ASTM D792 (Standard Test Methods for Density and Specific Gravity of Plastics), ISO 1183 (Plastics — Methods for Determining the Density of Non-Cellular Plastics), and ISO 2811 (Paints and Varnishes — Determination of Density). Calibration documentation meets ISO/IEC 17025 traceability requirements when performed with certified reference masses. The instrument’s firmware architecture supports full audit trails, electronic signature fields, and exportable logs required under FDA 21 CFR Part 11 for regulated pharmaceutical and medical device manufacturing.

Software & Data Management

Data capture is enabled via optional RS-232 or plug-and-play USB interface—requiring no additional drivers for Windows, macOS, or Linux systems. Raw weight and density values stream in ASCII format compatible with Microsoft Excel, LabChart, JMP, and custom LIMS platforms. Built-in statistical functions include mean, standard deviation, min/max, and coefficient of variation (CV%) calculation per measurement series. Exported datasets retain full metadata: date/time stamp, operator ID, sample ID, temperature input, medium type, and calibration status. Calibration reports generated on-device comply with ISO 9001 and ISO/IEC 17025 documentation standards, including uncertainty estimation placeholders and revision-controlled versioning.

Applications

• Quality assurance of injection-molded plastic components against density specification limits
• Verification of sintered metal part porosity and green density in powder metallurgy
• Batch-to-batch consistency monitoring of battery electrode slurries and electrolyte solutions
• Determination of water absorption rate and volumetric expansion coefficient in hygroscopic materials
• In-process density verification during chemical synthesis or polymerization reactions
• Educational demonstration of Archimedes’ principle and material property interrelationships
• Field-deployable density screening for geological core samples or recycled composite feedstock

FAQ

What density measurement methods does the EJ-120D support?
It implements the hydrostatic weighing method for solids (ASTM D792) and the sinker displacement method for liquids (ISO 2811), both based on buoyant force quantification.
Can the EJ-120D measure density of porous or irregularly shaped solids?
Yes—provided the sample is non-hygroscopic or stabilized prior to measurement; optional vacuum impregnation accessories are available for open-cell materials.
Is temperature compensation mandatory for accurate results?
While not mandatory, entering the actual fluid temperature significantly improves accuracy—especially when working near thermal transition points of common immersion media.
Does the instrument support multi-point calibration verification?
Yes—through user-defined calibration checks at multiple load points, with pass/fail status logged alongside deviation metrics.
How is compliance with GLP/GMP enforced in daily operation?
Via mandatory operator ID entry, automatic time/date stamping, immutable calibration report generation, and secure data export protocols that preserve chain-of-custody integrity.