HARKE HK-EVM Advanced Surface Tensiometer

Overview

The HARKE HK-EVM Advanced Surface Tensiometer is a precision laboratory instrument engineered for the quantitative determination of surface and interfacial tension using the standardized Du Noüy ring method. Based on the principle of measuring the maximum force required to detach a platinum-iridium ring from the liquid–air or liquid–liquid interface, the HK-EVM delivers high reproducibility and traceable results in compliance with ISO 1409, ASTM D971, and DIN 53914. Its robust mechanical architecture integrates a high-resolution load cell (0–120 g capacity), motorized vertical stage with sub-millimeter positioning control, and real-time temperature monitoring—enabling consistent measurements across a broad operational temperature range (0–90 °C). Designed for routine QC laboratories, R&D facilities, and academic surface science groups, the HK-EVM supports both static and dynamic surface tension evaluation under controlled thermal conditions.

Key Features

• Precision Du Noüy ring measurement system with automatic peak-force detection and zero-drift compensation
• High-resolution force transducer offering 0.01 mN/m resolution and ±0.01 mN/m accuracy over 0–100 mN/m range
• Motorized sample stage with programmable lift speed (0–10 mm/s) and 80 mm total travel, enabling precise immersion depth control
• Integrated digital temperature sensor with ±0.1 °C display accuracy and real-time thermal feedback loop
• Stainless-steel sample holder compatible with standard Φ50 mm glass or quartz cuvettes; chemically inert and autoclavable
• Modular design supporting optional electrically heated circulating jacket for isothermal interfacial studies (e.g., surfactant adsorption kinetics)
• Compact footprint (360 × 360 × 620 mm) and lightweight construction (20 kg) for benchtop integration in regulated environments

Sample Compatibility & Compliance

The HK-EVM accommodates aqueous solutions, organic solvents, polymer melts, emulsions, micellar systems, and low-viscosity biological fluids. It is routinely deployed in formulations involving latex dispersions, pharmaceutical surfactants, inkjet inks, and coating resins—where surface tension directly correlates with wetting behavior, foam stability, and colloidal dispersion integrity. The instrument meets essential requirements for GLP-compliant documentation: all measurement parameters—including timestamp, temperature, force curve, and operator ID—are logged automatically by the SFT-A software. Data export formats (CSV, TXT, PDF) support audit-ready reporting aligned with FDA 21 CFR Part 11 expectations when paired with appropriate user access controls and electronic signature protocols.

Software & Data Management

The SFT-A software suite provides intuitive graphical interface for instrument control, real-time force–distance curve visualization, and automated calculation of surface/interfacial tension values per ISO-defined algorithms. Calibration routines include multi-point weight-based load verification and ring geometry correction factors. All raw data files retain metadata (date/time, ambient humidity, operator, calibration status) and support version-controlled archiving. Batch processing mode enables comparative analysis across multiple samples under identical thermal and mechanical settings. Exported datasets are compatible with LIMS integration and third-party statistical platforms (e.g., JMP, OriginLab) for DOE-driven formulation optimization.

Applications

• Quality control of synthetic and natural latex emulsions in adhesive, paint, and dip-coating manufacturing
• Surfactant critical micelle concentration (CMC) determination and HLB optimization
• Evaluation of interfacial tension reduction at oil–water interfaces for enhanced oil recovery (EOR) formulations
• Stability assessment of nanoemulsions and Pickering systems via time-resolved surface tension profiling
• Regulatory testing of ophthalmic solutions and parenteral drug carriers per USP and Ph. Eur. 2.9.32
• Fundamental research on protein adsorption kinetics at air–water interfaces using temperature-ramped protocols

FAQ

What measurement method does the HK-EVM employ, and why is it suitable for latex systems?
It uses the Du Noüy ring method, which provides excellent sensitivity and repeatability for low-viscosity, low-surface-tension systems such as stabilized latex dispersions—without requiring specialized probes or complex fluid handling.
Can the HK-EVM measure interfacial tension between two immiscible liquids?
Yes, when used with a dual-phase sample cell and appropriate ring immersion protocol, it quantifies liquid–liquid interfacial tension per ASTM D1331 and ISO 6295.
Is temperature control built-in, or is external circulation required?
The base unit includes integrated temperature sensing and display; precise isothermal control requires the optional electrically heated circulating jacket, which maintains ±0.2 °C stability over extended runs.
How is calibration performed, and how often is it recommended?
Calibration utilizes certified weights and standard reference liquids (e.g., ultrapure water at 20 °C = 72.75 mN/m); daily zero calibration and weekly full-range verification are recommended for GMP-aligned workflows.
Does the SFT-A software support audit trails and user-level permissions?
Yes—when configured with Windows domain authentication and local database logging, it generates immutable audit trails compliant with ALCOA+ principles for regulated laboratories.