Hongtuo Technology ZM-105B Portable Intelligent Electronic Soap Film Flowmeter

Overview

The Hongtuo Technology ZM-105B Portable Intelligent Electronic Soap Film Flowmeter is a precision volumetric flow calibration instrument engineered for traceable, real-time measurement of low-to-moderate gas and liquid flow rates in field and laboratory environments. It operates on the fundamental principle of soap film displacement—where a thin, stable soap film is formed across the inner diameter of a calibrated vertical glass tube; the time required for the film to traverse a known distance between two optical sensors determines volumetric flow rate with high reproducibility. Unlike thermal or differential pressure-based methods, this technique provides direct volumetric measurement independent of fluid composition, density, or viscosity—making it ideal for calibrating critical sampling instrumentation where regulatory traceability is mandated. Designed in strict compliance with JJG 586–2006 “Verification Regulation for Soap Film Flowmeters”, the ZM-105B integrates real-time temperature, pressure, and volume correction algorithms to deliver standardized flow values referenced to 25 °C and 101.325 kPa (or user-defined reference conditions), ensuring metrological integrity across variable ambient conditions.

Key Features

• Microprocessor-controlled operation with automated data acquisition, calculation, and display of volumetric flow (mL/min), mass flow (g/min), elapsed time (0.01 s internal resolution), ambient temperature (±0.2 °C), and barometric pressure (±0.1 kPa)
• Dual optical sensor system with self-diagnostic capability—simultaneously monitors photodiode signal intensity and allows fine-tuning of sensitivity via onboard potentiometer for optimal film detection under varying lighting or film thickness conditions
• Integrated environmental compensation: automatic correction for temperature, pressure, and tube geometry per ISO 6145-2 and ASTM D6196 standards
• Ultra-portable form factor (90 × 150 × 280 mm; 1.3 kg) with ruggedized ABS housing and sealed optical path—suitable for field deployment in environmental monitoring stations, industrial hygiene surveys, and mobile labs
• Intelligent power management: 4.8 V/700 mAh rechargeable battery supports >24 h standby; auto-backlight dimming after 60 s inactivity and full shutdown after 5 min idle; external 9 V DC input enables continuous operation and simultaneous battery charging with automatic transition to float charge mode

Sample Compatibility & Compliance

The ZM-105B is compatible with all non-corrosive, non-viscous gases and liquids that support stable soap film formation—including ambient air, nitrogen, helium, CO₂, compressed dry air, water, and aqueous solutions. It is not suitable for solvents that rapidly evaporate or degrade soap surfactants (e.g., acetone, ethanol >20% v/v). Its design satisfies the functional and metrological requirements of JJG 586–2006, and its measurement methodology aligns with the principles outlined in ISO/IEC 17025 for calibration laboratories. The instrument supports GLP-compliant workflows through timestamped, non-editable measurement logs stored in internal memory, and its documented uncertainty budget (±1% at full scale, k=2) meets typical QA/QC thresholds for environmental sampler verification per EPA Method IO-3A and EN 12341.

Software & Data Management

While the ZM-105B operates as a standalone, embedded-system device without PC connectivity, all measurements are timestamped and retained in non-volatile memory (up to 500 records). Each record includes raw transit time, corrected flow value, temperature, pressure, and sensor status flags. Data export is performed manually via on-screen review and transcription. For integration into enterprise QA systems, users may log results directly into LIMS or Excel using standardized templates aligned with 21 CFR Part 11 audit trail requirements—though native electronic signature or remote data transfer is not supported. Firmware updates are performed locally via micro-USB (service port, not user-accessible), and calibration constants are protected by write-lock mechanisms to prevent unauthorized modification.

Applications

• Calibration and verification of personal and stationary air samplers (e.g., SKC, Gilian, Casella models) used in occupational exposure assessment per OSHA ID-121 and NIOSH Manual of Analytical Methods (NMAM)
• Field validation of dust and aerosol sampling pumps prior to and during PM₂.₅/PM₁₀ monitoring campaigns
• Verification of carrier and auxiliary gas flows in GC systems—particularly for ECD, FID, and TCD detectors requiring precise flow control below 100 mL/min
• Traceable recalibration of rotameters, critical orifice meters, and laminar flow elements in HVAC and cleanroom monitoring systems
• Flow characterization of low-flow liquid delivery modules in analytical chemistry and environmental sample preparation systems
• Supporting method validation studies under ISO 17025-accredited laboratories where primary standard traceability is required

FAQ

What standards does the ZM-105B comply with?
It is designed and verified in accordance with JJG 586–2006, and its measurement methodology is consistent with ISO 6145-2, ASTM D6196, and EPA IO-3A for flow calibration of environmental samplers.
Can the ZM-105B measure liquid flow directly?
Yes—it supports low-viscosity liquids (e.g., water, dilute saline) provided they enable stable, contiguous soap film formation; however, calibration must be performed with the same liquid used in application due to surface tension dependencies.
Is temperature and pressure compensation automatic?
Yes—the unit continuously reads ambient temperature and pressure via onboard sensors and applies correction factors in real time using the ideal gas law and tube dimensional coefficients.
How is traceability maintained during field use?
Each unit ships with a factory calibration certificate referencing NIM (National Institute of Metrology, China) traceable standards; users may perform intermediate verification using certified reference orifices or gravimetric methods per ISO/IEC 17025 clause 7.7.
Does the ZM-105B support multi-point calibration?
No—it is a single-point, primary-standard instrument; linearity is verified during manufacture across its full range (0.3–30,000 mL/min), and no user-adjustable multi-point calibration is implemented to preserve metrological hierarchy.