Shengtai Instruments SH107 Ring Method Interfacial Tensiometer

Overview

The Shengtai Instruments SH107 Ring Method Interfacial Tensiometer is a dedicated benchtop instrument engineered for precise and repeatable measurement of surface tension at liquid–gas interfaces and interfacial tension at liquid–liquid boundaries—particularly mineral oil–water systems. It operates on the classical Du Noüy ring method, a gravimetric technique standardized in GB/T 6541 (equivalent to ISO 6295 and ASTM D971), where the maximum force required to detach a platinum–iridium ring from the interface is measured and converted into interfacial tension using geometric correction factors. This principle ensures traceability to internationally accepted physical standards and enables reliable quantification across diverse industrial formulations. The SH107 is specifically optimized for applications demanding regulatory compliance in power generation, petrochemical refining, lubricant formulation, and quality control laboratories where interfacial behavior directly correlates with oxidation stability, emulsion resistance, and contaminant detection.

Key Features

• Microcontroller-based automation with one-button measurement initiation and auto-calculated result output
• High-resolution LCD display with real-time tension readout and temperature monitoring
• Precision platinum–iridium ring assembly compliant with GB/T 6541 geometry specifications (diameter: 19.6 mm, wire diameter: 0.37 mm)
• Dual-speed lifting mechanism: fast mode (1 mm/s) for coarse positioning; slow mode (0.3–0.4 mm/s) for controlled detachment during peak-force capture
• Integrated temperature compensation algorithm to correct for thermal drift within the operational range (10–30 °C)
• Non-volatile memory for parameter retention after power loss, including calibration offsets and user-defined correction coefficients
• Robust mechanical architecture with vibration-damped base and linear motion guide ensuring high reproducibility (RSD < 0.5% for repeated measurements under controlled conditions)

Sample Compatibility & Compliance

The SH107 supports aqueous solutions, hydrocarbon solvents, transformer oils, insulating fluids, surfactant dispersions, and immiscible liquid pairs such as diesel–water or silicone oil–glycerol. Its design conforms to GB/T 6541-1986 (Determination of interfacial tension of mineral oil against water—Du Noüy ring method), which aligns functionally with ISO 6295:1983 and ASTM D971-22. While not certified for GLP or FDA 21 CFR Part 11 out-of-the-box, the instrument’s deterministic measurement sequence, audit-ready manual logging capability, and stable hardware platform make it suitable for use in environments governed by internal QA/QC protocols requiring documented traceability. All metallic wetted parts are constructed from corrosion-resistant stainless steel and platinum–iridium alloy to prevent catalytic interference or surface contamination.

Software & Data Management

The SH107 operates as a standalone embedded system without external PC dependency. Measurement data—including raw force values, calculated interfacial tension (mN/m), ambient temperature (°C), test timestamp, and operator ID—is displayed and retained in local memory. Results can be printed via integrated thermal printer (paper roll included). For laboratory integration, users may manually transcribe values into LIMS or Excel-based tracking systems. Optional RS-232 serial output (available upon request) enables basic ASCII data streaming for third-party acquisition software. Firmware supports firmware-upgradable calibration tables and supports multi-point verification using certified reference liquids (e.g., ultrapure water at 20 °C: 72.75 mN/m; 2-propanol: 21.7 mN/m).

Applications

• Transformer oil aging assessment in electric utilities per IEC 60429 and IEEE C57.106 guidelines
• Quality assurance of turbine oils and hydraulic fluids for hydrolytic stability evaluation
• Surfactant efficacy screening in enhanced oil recovery (EOR) formulations
• Emulsion stability analysis in food-grade lubricants and pharmaceutical excipients
• Routine QC testing in refinery labs for crude desalting efficiency and demulsifier performance
• Educational use in university physical chemistry laboratories for capillary and interfacial phenomena instruction

FAQ

What standard methods does the SH107 support?
It implements the Du Noüy ring method per GB/T 6541, equivalent to ISO 6295 and ASTM D971.
Can the SH107 measure dynamic interfacial tension?
No—it performs equilibrium interfacial tension measurements only; it is not equipped for time-resolved or oscillatory analysis.
Is temperature control built into the instrument?
No—the SH107 monitors ambient temperature but does not include Peltier or bath-based temperature regulation; external thermostatted sample holders are recommended for strict thermal control.
What maintenance is required for the platinum ring?
The ring must be cleaned with ethanol or acetone before each use and annealed in a Bunsen flame until red-hot to remove organic residues and restore surface homogeneity.
Does the instrument support automatic density correction?
No—density input is not required for ring-method calculations under standard conditions; corrections for non-aqueous subphases are applied manually using manufacturer-supplied lookup tables.