Tianhong TH-307 VOCs Zero Air Generator

Overview

The Tianhong TH-307 VOCs Zero Air Generator is a laboratory-grade zero air source engineered specifically for calibration and operational support of volatile organic compounds (VOCs) monitoring systems—particularly as an integral component of the TH-300B Ambient Air VOCs Automated Monitoring System. It operates on a multi-stage purification principle: ambient air is drawn in, sequentially dried via Nafion® membrane dehydration, catalytically oxidized to remove hydrocarbons (including methane and non-methane hydrocarbons), and further scrubbed of carbon monoxide and residual moisture. The resulting zero air meets stringent ASTM D6196–22 and ISO 8573-1 Class 1 specifications for hydrocarbon content (<0.1 ppm C₁–C₁₀), CO <0.1 ppm, and dew point ≤ –40 °C at atmospheric pressure. This level of purity ensures metrological traceability when used for zero-point calibration of FID (flame ionization detection), PID (photoionization detection), and GC-FID/GC-MS systems in ambient air quality laboratories, EPA Method TO-15/TO-17 compliance environments, and reference measurement facilities.

Key Features

• Integrated Nafion® membrane dryer delivering continuous dew point control ≤ –40 °C with long-term stability and no consumable desiccant replacement required
• Catalytic hydrocarbon removal module achieving >99.9% total hydrocarbon (THC) elimination and >99.9% methane (CH₄) abatement—validated per EPA Protocol 2 requirements
• Precision thermal regulation system with ±0.5 °C long-term temperature stability across operating range (20–35 °C ambient)
• High-accuracy pressure regulation using stainless-steel diaphragm-based pressure-reducing valves; output pressure stability maintained within ±0.02 MPa over 24-hour continuous operation
• Automated process control architecture featuring embedded microprocessor logic for coordinated temperature, pressure, and flow management without manual intervention
• Dual-safety protection system including overtemperature cutoff (≥65 °C), overpressure shutdown (≥0.8 MPa), and audible alarm signaling for fault conditions
• Low-noise design: acoustic emission <45 dBA at 1 m distance, suitable for placement inside analytical laboratories or mobile monitoring vans

Sample Compatibility & Compliance

The TH-307 generates zero air compatible with all major VOCs analyzers requiring ultra-low background gas, including but not limited to Thermo Fisher Scientific TraceGC, Agilent 7890/8890 GC systems, and Shimadzu GC-2010 Plus platforms. Its output meets the zero air specification referenced in U.S. EPA Methods TO-14A, TO-15, TO-17, and EU standard EN 13528-3 for ambient air VOCs measurement. The unit complies with IEC 61000-6-2 (EMC immunity) and IEC 61000-6-4 (EMC emission) standards. While not certified under FDA 21 CFR Part 11, its operational logs and alarm records are timestamped and exportable for GLP/GMP-aligned internal audit purposes.

Software & Data Management

The TH-307 operates via front-panel membrane keypad with real-time LED display of core parameters: outlet pressure (MPa), internal catalyst bed temperature (°C), and system status (e.g., “STANDBY”, “PURIFYING”, “ALARM”). No external software or PC interface is provided; however, analog 4–20 mA outputs are available for remote pressure and temperature monitoring into SCADA or LIMS environments. All alarm events—including overtemperature, overpressure, and airflow interruption—are logged with UTC timestamps and retained for up to 30 days in non-volatile memory. Data export is supported via USB-C port in CSV format for integration into QA/QC documentation workflows.

Applications

• Zero-point calibration of FID, PID, and PTR-MS instruments in fixed-site and mobile ambient air monitoring stations
• Carrier gas supply for GC systems performing speciated VOC analysis per EPA Method TO-15 (canister-based) and TO-17 (sorbent tube-based)
• Make-up gas and combustion air for hydrogen flame ionization detectors requiring consistent stoichiometric ratios
• Preparation of certified VOC reference standards in dynamic dilution systems (e.g., Brooks Rand 4040, Mesa Labs Enviro-1000)
• Baseline verification and drift correction in continuous emissions monitoring systems (CEMS) deployed for industrial fence-line monitoring
• Supporting ISO/IEC 17025-accredited laboratories during method validation and uncertainty budgeting exercises

FAQ

What is the maximum continuous flow rate supported by the TH-307?
The unit delivers stable zero air at up to 15 L/min at 0.3 MPa outlet pressure, with flow consistency maintained within ±2% across rated load.
Does the TH-307 require periodic catalyst replacement?
The catalytic oxidation module is designed for ≥12 months of continuous operation under typical ambient air conditions (≤60% RH, ≤25 °C); replacement interval depends on inlet air quality and usage frequency.
Can the TH-307 be integrated into a centralized lab gas network?
Yes—its outlet is fitted with a 1/4″ VCR fitting compatible with stainless-steel tubing and standard gas distribution manifolds; backpressure must remain below 0.5 MPa.
Is the Nafion® membrane serviceable in-field?
The Nafion® dryer assembly is a sealed, maintenance-free subunit; no user-serviceable parts exist—replacement requires factory recalibration.
What certifications does the TH-307 hold for international shipment?
It carries CE marking per EMC Directive 2014/30/EU and RoHS 2011/65/EU compliance documentation; export to North America requires additional UL/CSA safety evaluation.