TH-ZM10 Intelligent Electronic Soap Film Flowmeter

Overview

The TH-ZM10 Intelligent Electronic Soap Film Flowmeter is a portable, microprocessor-controlled primary standard flow calibration instrument engineered for high-reproducibility volumetric flow verification of low-flow gas sampling devices in environmental monitoring applications. It operates on the fundamental principle of soap film flow measurement — a gravimetrically traceable, time-of-flight method where a calibrated soap film traverses a precision-bore vertical tube of known internal diameter and length. The elapsed transit time is measured with ±0.01 s resolution, and volumetric flow is calculated using the fixed geometric volume of the tube segment and real-time environmental compensation. Designed specifically for field use, the TH-ZM10 delivers certified accuracy compliant with Class 1 specifications per JJG 577–2012 (Chinese National Metrological Verification Regulation for Gas Flowmeters) and aligns with international best practices referenced in ISO/IEC 17025:2017 for calibration laboratories.

Key Features

• Integrated monolithic architecture combining optical film detection sensor, borosilicate glass soap film tube, and embedded ARM-based control electronics — eliminating external cabling or auxiliary modules.
• Real-time environmental compensation engine: supports manual input of local atmospheric pressure (kPa) and ambient temperature (°C), automatically retrieving saturation vapor pressure (kPa) and saturated water temperature (°C) from NIST-traceable thermodynamic lookup tables aligned with ASTM D1948 and ISO 8573-1 Annex B.
• Triple-mode flow display: simultaneous readout of actual volumetric flow (L/min), standardized flow at 25 °C and 101.325 kPa (dry), and reference-condition flow (e.g., 20 °C / 101.325 kPa) — configurable via front-panel interface.
• Class 1 accuracy (±1% of reading, 1–30 L/min range) verified against national metrological standards; supplied with CNAS-accredited calibration certificate traceable to NIM (National Institute of Metrology, China).
• Compact form factor (185 × 95 × 65 mm), weight < 0.8 kg, powered by rechargeable Li-ion battery (≥8 h continuous operation) or USB-C DC input — optimized for handheld use during stack testing, ambient air sampler audits, and mobile QA/QC field campaigns.

Sample Compatibility & Compliance

The TH-ZM10 is validated for calibration of low-flow gas sampling instruments including but not limited to: personal and stationary respirable dust samplers (e.g., SKC, Casella, Thermo Fisher models), beta attenuation monitors (BAM), tapered element oscillating microbalances (TEOM), and filter-based PM_2.5/PM₁₀ samplers deployed in national air quality monitoring networks. It meets functional requirements specified in EPA Method IO-3A, EN 12341:2014 (ambient PM measurement), and HJ/T 368–2007 (Chinese standard for calibrating environmental air samplers). Its design supports GLP-aligned documentation workflows, with timestamped calibration records exportable via USB for audit trail retention.

Software & Data Management

While the TH-ZM10 operates as a standalone field instrument with no mandatory PC dependency, it supports optional data logging via USB mass storage mode. All calibration events — including date/time stamp, entered T/P values, raw transit time, compensated flow values, operator ID (user-defined), and pass/fail status — are stored in CSV format. The firmware implements secure parameter locking (password-protected configuration mode) and maintains an immutable internal log of the last 100 calibration sessions. No cloud connectivity or proprietary software is required; exported files comply with FDA 21 CFR Part 11 principles when used within validated laboratory information management systems (LIMS).

Applications

• Field verification and adjustment of flow rates on federal equivalent method (FEM) and federal reference method (FRM) particulate samplers prior to deployment.
• Annual or semi-annual recalibration of fixed-site ambient air monitoring stations (e.g., China’s National Urban Air Quality Monitoring Network).
• QA/QC auditing of occupational hygiene sampling pumps used in industrial hygiene surveys per GBZ/T 192.1–2018.
• Verification of flow stability during method validation studies for ISO 12103-1 aerosol generation systems.
• Educational use in environmental engineering labs for teaching primary flow measurement principles and uncertainty analysis in gas metrology.

FAQ

Is the TH-ZM10 suitable for calibrating mass flow controllers (MFCs)?
No — the TH-ZM10 is a volumetric primary standard intended for low-flow (<30 L/min) gas samplers operating near atmospheric pressure. It does not compensate for gas composition or compressibility effects inherent in MFC calibration.
Can the flow range be extended beyond 30 L/min?
The instrument’s mechanical and optical design is optimized for 1–30 L/min. Higher flows induce film instability and measurement uncertainty beyond Class 1 limits; alternate calibration methods (e.g., critical flow venturi) are recommended above this range.
Does the device support automatic temperature/pressure sensing?
No — ambient temperature and barometric pressure must be manually entered. This ensures full operator control and avoids drift errors associated with low-cost integrated sensors in variable field environments.
How often does the TH-ZM10 require recalibration?
Annual recalibration is recommended per ISO/IEC 17025 and JJG 577–2012; the included CNAS certificate specifies the validity period and uncertainty budget (k=2) for each delivered unit.
Is the soap solution provided with the instrument?
Yes — a 50 mL vial of proprietary non-toxic, low-evaporation soap solution (formulated for stable film formation across 5–40 °C) is included, along with a calibrated dropper and cleaning swabs.