Yuntang YT-30L Multi-Range Electronic Soap Film Flowmeter

Overview

The Yuntang YT-30L Multi-Range Electronic Soap Film Flowmeter is a primary-standard gas flow measurement instrument engineered for high-accuracy volumetric flow calibration and verification in laboratory, environmental monitoring, and industrial quality control settings. It operates on the well-established soap film principle—where a thin, stable soap film is formed across a calibrated glass tube, and its transit time between two precisely spaced optical sensors (infrared) is measured to determine volumetric flow rate. As a primary standard, it requires no external calibration traceable to a higher-order reference; its accuracy derives directly from dimensional metrology (tube bore cross-section) and high-resolution timing. This device meets the metrological requirements defined in JJG 586–2006 “Verification Regulation for Soap Film Flowmeters” and serves as a transfer standard for calibrating secondary flow devices such as rotameters, critical orifices, thermal mass flowmeters, and GC carrier gas flow controllers.

Key Features

• Multi-range capability with selectable full-scale ranges up to 30 L/min—enabling precise low-flow measurements (down to 30 mL/min) without range-switching artifacts or manual recalibration.
• Integrated microcontroller-based timing system with 0.001 s resolution and automatic film detection via dual infrared photogates—ensuring consistent start/stop triggering independent of operator technique.
• Onboard temperature and pressure compensation algorithms support real-time conversion between actual (operating condition) flow and standardized flow (e.g., 25 °C, 101.325 kPa), compliant with ISO 10780 and EPA Method 2.
• Self-diagnostic firmware performs continuous sensor health checks, detects film rupture or incomplete traversal, and flags invalid measurements—eliminating manual intervention during routine calibration workflows.
• Programmable averaging function allows user-defined repetition count (1–99 cycles) with statistical reporting (mean, SD, CV%)—critical for GLP-compliant documentation and uncertainty budgeting per ISO/IEC 17025.
• Field-portable design with integrated rechargeable Li-ion battery (8.4 V / 1200 mAh), supporting >300 h standby and >8 h continuous operation—ideal for mobile ambient air sampling audits and stack testing.

Sample Compatibility & Compliance

The YT-30L is compatible with non-corrosive, non-condensing gases including ambient air, nitrogen, helium, carbon dioxide, and synthetic air mixtures. Its borosilicate glass measurement tube resists chemical degradation from common calibration gases and cleaning agents. The instrument complies with national metrological verification requirements (JJG 586–2006) and supports traceability to China’s National Institute of Metrology (NIM). While not certified to international standards such as ISO/IEC 17025 itself, its performance characteristics—including ±1% accuracy, documented repeatability (<0.5% RSD), and linear response across its dynamic range—align with best practices for primary flow verification per ASTM D3195 and ISO 5167 Annex F. It is routinely deployed in laboratories undergoing CNAS accreditation and environmental monitoring agencies fulfilling China’s HJ/T 375–2007 technical specifications for air sampler calibration.

Software & Data Management

The YT-30L operates autonomously without PC connectivity; all data acquisition, calculation, and storage occur onboard. Measurement records—including timestamp, raw transit time, calculated flow (actual and standard), temperature/pressure inputs, and pass/fail status—are stored in non-volatile memory (up to 500 entries). Data export is supported via USB-C interface using vendor-provided Windows-compatible utility software, which generates CSV reports compliant with 21 CFR Part 11 audit trail requirements (user login, action timestamp, data integrity checksum). The software enables batch export, trend analysis, and certificate-of-calibration generation aligned with ISO 10012 guidelines.

Applications

• Calibration and verification of low-flow air samplers (e.g., personal respirable dust pumps, VOC canister draw systems).
• Flow validation of gas chromatography carrier and detector gases prior to method qualification.
• Performance auditing of critical orifice-based emission monitors and continuous emission monitoring systems (CEMS).
• Field verification of portable photoionization detectors (PID), electrochemical sensors, and optical particle counters requiring known sample draw rates.
• Teaching and metrology training in university analytical chemistry and environmental engineering labs—demonstrating primary standard principles and uncertainty propagation.

FAQ

What defines this instrument as a “primary standard” flowmeter?

It relies solely on geometric dimensions (internal tube diameter) and time-of-flight measurement—both directly traceable to SI units—without dependence on empirical calibration curves or fluid property assumptions.
Can the YT-30L measure humid or particulate-laden gas streams?

No. Moisture condensation or aerosol deposition disrupts soap film integrity and optical detection; only clean, dry, non-reactive gases are suitable.
Is pressure and temperature compensation mandatory for regulatory reporting?

Yes—EPA, ISO, and Chinese environmental standards require reporting at standardized conditions; the built-in compensation engine applies ideal gas law corrections using user-entered or optional external sensor inputs.
How is measurement uncertainty estimated for QA/QC documentation?

Uncertainty contributors include timing resolution (±0.001 s), tube bore tolerance (±0.15%), temperature sensor error (±0.3 °C), and pressure sensor error (±0.5 kPa); typical combined expanded uncertainty (k=2) is ≤1.2% for flows >100 mL/min.
Does the device support GLP-compliant electronic signatures?

The desktop software supports role-based user accounts, digital signature capture, and immutable audit logs—but the instrument itself does not perform biometric or cryptographic signing.