Beifen Sanpu ZM-105 Electronic Soap Film Flowmeter for Academic Laboratory Use

Overview

The Beifen Sanpu ZM-105 Electronic Soap Film Flowmeter is a precision positive displacement flow measurement instrument engineered for traceable, low-to-medium gas flow calibration in academic laboratories, environmental monitoring centers, occupational health institutions, and analytical R&D facilities. It operates on the fundamental principle of soap film displacement: a thin, stable soap film is generated across the calibrated bore of a vertical glass tube; as gas flows upward through the tube, the film ascends at a velocity directly proportional to volumetric flow rate. The instrument precisely measures the transit time between two optically detected positions—upper and lower infrared sensors—to compute flow with high temporal resolution (0.1 s display, 0.01 s internal timing). Unlike thermal or differential pressure-based meters, the ZM-105 delivers direct volumetric measurement independent of gas composition, making it ideal for calibrating critical sampling devices where traceability and repeatability are mandated by regulatory protocols.

Key Features

• Microprocessor-controlled operation with real-time digital display of flow (mL/min), elapsed time (s), temperature (°C), pressure (kPa), and corrected volume (mL)
• Integrated temperature and pressure compensation algorithms compliant with JJG 586–2006, enabling automatic conversion to standard conditions (e.g., 25°C, 101.325 kPa)
• Dual optical sensor self-diagnostic function: simultaneous measurement of photodiode output allows user-adjustable sensitivity tuning via internal potentiometer
• Onboard rechargeable 4.8 V / 700 mAh Ni-MH battery with state-of-charge monitoring and visual charge-status indicator
• External 9 V DC power input supports concurrent operation and battery recharging; intelligent float-charging logic prevents overcharge and extends cycle life (>500 cycles)
• Compact monolithic design integrating sensor array, calibrated soap film tube, control electronics, and user interface in a single portable housing (90 × 150 × 280 mm, 1.3 kg)
• Energy-efficient power management: backlight deactivation after 60 seconds of inactivity; full system shutdown after 300 seconds of no keypress or sensor event

Sample Compatibility & Compliance

The ZM-105 is validated for use with non-corrosive, non-condensing gases including ambient air, nitrogen, helium, carbon dioxide, and synthetic calibration mixtures. It is not suitable for vapors, aerosols, or humidified streams that may disrupt film stability. Its design adheres strictly to the metrological requirements outlined in JJG 586–2006, which defines verification procedures, uncertainty budgets, and allowable error limits for primary-standard soap film flowmeters used in Chinese national metrology laboratories. While not certified to ISO/IEC 17025 or ASTM D3195, its documented repeatability (<0.5%) and accuracy (±1%) align with best-practice validation criteria for secondary calibration standards in GLP-compliant environmental testing labs. The instrument’s passive mechanical measurement principle ensures immunity to electromagnetic interference and eliminates zero drift associated with electronic transducers.

Software & Data Management

The ZM-105 operates autonomously without PC dependency—data acquisition, correction, and display occur entirely onboard. All measured parameters (time, raw volume, T, P, corrected flow) are retained in volatile memory during active use and can be manually recorded. Though no proprietary software or USB interface is provided, the device’s deterministic output format (numeric LCD with labeled units) facilitates structured manual entry into LIMS or Excel-based QA/QC logs. For institutions requiring audit trails, the instrument’s fixed firmware version (v2.3, factory-installed), absence of configurable settings, and deterministic correction algorithm support retrospective traceability—a prerequisite for internal GLP audits and method validation documentation per ISO/IEC 17025 Clause 7.7.

Applications

• Calibration and verification of personal and stationary air samplers (e.g., SKC, Gilian, BGI models) per NIOSH Method 0500 and EPA Compendium Method TO-11A
• Verification of flow rates in respirable dust cyclones and PM_2.5/PM₁₀ impactors
• Gas flow auditing of GC carrier gas lines (He, N₂, H₂) and detector auxiliary gases
• Field validation of rotameters and critical orifice flow controllers prior to deployment
• Performance checks of stack gas sampling probes and dilution systems in environmental compliance testing
• Teaching laboratory demonstrations of laminar flow dynamics, gas laws, and volumetric metrology principles

FAQ

What gas types can be measured with the ZM-105?
The instrument is designed for dry, non-reactive gases such as air, nitrogen, helium, argon, and carbon dioxide. Avoid use with corrosive, condensable, or high-humidity streams.
Does the ZM-105 require annual recalibration?
Per JJG 586–2006, verification should be performed before each day’s use when employed as a reference standard; full recalibration by an accredited lab is recommended annually or after physical shock or sensor cleaning.
Can the ZM-105 measure liquid flow?
No—it is a gas-phase volumetric meter relying on soap film formation; liquids will not generate a stable, measurable film in the calibrated tube.
How is temperature and pressure correction applied?
Internal sensors continuously sample ambient T and P; the microcontroller applies the ideal gas law to convert measured volume/time to standardized volumetric flow (e.g., mL/min at 25°C and 101.325 kPa).
Is the ZM-105 compliant with FDA 21 CFR Part 11?
No—it lacks electronic audit trail, user authentication, or data export capabilities required for Part 11 compliance; it is intended for manual data recording in non-GMP research or teaching environments.