Junfang Lihua HXPQX-500 Circular Gas Distribution Test Chamber for Combustible Gas Detectors

Overview

The Junfang Lihua HXPQX-500 Circular Gas Distribution Test Chamber is an engineered environmental test system designed specifically for the calibration, performance verification, and compliance testing of combustible gas detectors under controlled, repeatable airflow conditions. Based on a closed-loop annular wind tunnel architecture, the chamber integrates precision airflow regulation, programmable directional exposure, and traceable gas mixing to replicate real-world deployment scenarios—including variable wind velocity, detector orientation, and dynamic gas concentration profiles. Its design directly supports the test requirements outlined in GB 15322.1–2019, GB 15322.2–2019, and GB 15322.3–2019 for point-type combustible gas detectors used in industrial safety applications. The chamber operates on the principle of laminarized, velocity-stabilized gas transport, enabling accurate delivery of certified gas mixtures to detector sampling inlets while maintaining uniform flow field distribution across the test zone—critical for evaluating response time, alarm repeatability, and directional sensitivity.

Key Features

• Annular closed-loop wind tunnel with integrated flow straightening vanes, guide plates, and adjustable inlet/exhaust dampers to ensure stable, low-turbulence airflow across the full velocity range (0–7 m/s ±0.2 m/s)
• Eight pre-programmed airflow setpoints (0.8, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 6.5 m/s) for standardized high-speed gas exposure tests per GB 15322.1 Clause 6.7
• Motorized 3-axis rotational platform supporting 360° continuous rotation and discrete 45° step positioning in X/Y/Z orientations—enabling full spatial characterization of detector sensitivity
• 7-inch industrial-grade touch LCD control panel with real-time display of airflow velocity, operational status, test mode, and alarm logs
• Automated gas purge cycle via dedicated exhaust fan (DN50) and motorized exhaust valve to ensure residual gas clearance between test sequences
• Modular interface architecture: RS485/RS232 serial communication, MODBUS-RTU protocol support, and configurable digital I/O channels for integration with external gas analyzers, dosing units, or laboratory data acquisition systems
• Structural rigidity and sealed construction compliant with IP54-rated enclosure standards for use in non-hazardous laboratory environments

Sample Compatibility & Compliance

The HXPQX-500 accommodates standard 19-inch rack-mount and wall-mounted combustible gas detectors (including catalytic bead, infrared, and semiconductor-based sensors) with sampling inlets up to Ø50 mm. It supports test protocols defined in national and international safety standards including GB 15322.1–2019 (performance requirements and test methods), GB/T 29308–2012 (calibration procedures), and aligns with functional equivalency principles referenced in IEC 60079-29-1 and EN 61779-1 for detector validation. While not intrinsically safe itself, the chamber is intended for use with certified gas mixtures at concentrations below the lower explosive limit (LEL) and requires connection to externally certified gas analysis instrumentation (e.g., paramagnetic or tunable diode laser analyzers) for concentration verification. All mechanical and electrical components meet CE-marked EMC and low-voltage directive requirements for laboratory equipment.

Software & Data Management

The embedded controller firmware provides deterministic real-time control of airflow, rotation, and purge cycles without reliance on external PCs. Test parameters—including velocity setpoint, rotation angle, dwell time, and sequence duration—are stored in non-volatile memory and can be recalled as named test profiles. Event logging records timestamped operational states, airflow deviations (>±0.3 m/s), and fault codes (e.g., overtemperature, motor stall, communication timeout). Data export is supported via USB flash drive (CSV format) or MODBUS register polling, enabling traceability for GLP-compliant calibration records. Optional integration with third-party SCADA or LIMS platforms is achievable through standard MODBUS-RTU mapping—supporting audit-ready documentation for ISO/IEC 17025 accredited laboratories.

Applications

• Alarm action value verification and repeatability assessment per GB 15322.1 Clause 6.2
• Directional response evaluation across all three orthogonal axes under static and dynamic airflow conditions
• Response time measurement under calibrated gas pulses at multiple velocities (e.g., 1 m/s vs. 6.5 m/s) to assess aerodynamic interference effects
• Long-term stability monitoring via repeated exposure cycles over 7–30 days
• Low-concentration operation testing (e.g., 10–25% LEL methane in air) with validated gas analysis feedback
• High-velocity gas jet testing simulating ducted or outdoor installation environments
• Factory acceptance testing (FAT) and type examination for detector manufacturers seeking CCC or CNAS certification

FAQ

Does the HXPQX-500 include an integrated gas analyzer?

No—the chamber provides dedicated gas inlet/outlet ports and mounting provisions for external analyzers (e.g., paramagnetic O₂, NDIR CH₄, or electrochemical CO sensors), but the analyzer itself is optional and must be selected based on target gas species and required detection limits.

Can the rotation platform accommodate detectors heavier than 10 kg?

Yes—the motorized 3-axis turntable has a rated load capacity of 15 kg and features precision harmonic drive gearing to maintain angular accuracy within ±0.5° across full 360° motion.

Is the airflow velocity calibrated and traceable to national standards?

Air velocity sensors are factory-calibrated against NIM-traceable hot-wire anemometers; calibration certificates are provided with each unit, and periodic recalibration is recommended annually per ISO/IEC 17025 guidelines.

What safety interlocks are implemented?

The system includes hardware-based airflow loss detection, overtemperature cutoff (≥65°C), emergency stop circuitry compliant with IEC 60204-1, and automatic purge activation upon test completion or fault condition.

Is remote operation possible via Ethernet or Wi-Fi?

The base configuration supports only RS485/RS232; Ethernet or Wi-Fi connectivity requires an optional gateway module (sold separately) with MODBUS TCP translation capability.