BQHL-II / BQHL-IV Digital Constant-Flow Air Sampler

Overview

The BQHL-II and BQHL-IV Digital Constant-Flow Air Samplers are precision-engineered instruments designed for regulated, quantitative collection of airborne contaminants in indoor environmental quality (IEQ) assessments. These samplers operate on the principle of electronically controlled, pressure-compensated constant-flow aspiration—ensuring volumetric accuracy across variable backpressure conditions encountered during sorbent tube or impinger-based sampling. Engineered specifically to meet the technical requirements of GB 50325–2020 “Code for Control of Indoor Environmental Pollution in Civil Building Engineering”, they support standardized sampling of formaldehyde, ammonia, benzene, and total volatile organic compounds (TVOC) in residential, commercial, and institutional buildings prior to occupancy or post-renovation. Each unit integrates a microprocessor-controlled flow regulation system with real-time digital feedback, enabling stable flow delivery independent of filter loading or adsorbent resistance changes over time.

Key Features

• Dual-channel (BQHL-II) and quad-channel (BQHL-IV) configurations allow simultaneous sampling from multiple locations or analytes—reducing field deployment time and improving inter-sample comparability.
• High-stability constant-flow control with ≤±3% accuracy across the full 300–600 mL/min range, validated per ISO 16000-2 and aligned with US EPA TO-17 methodology prerequisites.
• Backlit LCD interface provides intuitive navigation for setting flow rate, sampling duration, pause/resume cycles, and real-time monitoring of elapsed time and accumulated volume.
• Integrated low-battery warning and under-voltage indication ensure data integrity by preventing incomplete sampling events.
• Compact, ergonomic chassis (277 × 200 × 275 mm) with reinforced polymer housing enables secure handheld operation and convenient transport in field kits.
• Ultra-low acoustic signature (≤40 dB[A]) minimizes disturbance during occupied-space sampling—critical for office, school, and healthcare facility applications.
• Rechargeable battery system supports ≥8 hours of continuous operation at 500 mL/min; full recharge completes in ≤4 hours via standard 220 V/50 Hz input.

Sample Compatibility & Compliance

The BQHL series is compatible with widely accepted passive and active sampling media, including DNPH-coated silica gel tubes (for carbonyls), activated charcoal tubes (for VOCs), and borosilicate impingers containing absorption solutions (e.g., H₂SO₄-glycine for ammonia). All operational parameters—including flow calibration traceability, timer resolution (±1 s), and volume integration algorithms—are documented to support GLP-compliant reporting. The instrument conforms to GB 50325–2020 Annex D test protocols and satisfies functional equivalency requirements referenced in ISO 16017-1 (indoor air—sampling strategies) and ASTM D5197 (determination of formaldehyde). While not intrinsically rated for hazardous areas, optional ATEX-compatible accessories may be integrated upon request for controlled industrial environments.

Software & Data Management

No proprietary PC software is bundled; however, all sampling parameters and timestamps are retained in non-volatile memory and displayed directly on the LCD. For laboratory information management system (LIMS) integration, users may export manually recorded data—including start/stop times, set flow rates, and final sampled volumes—into compliant audit trails. The device supports 21 CFR Part 11–aligned documentation practices when paired with standardized field logbooks and electronic record templates. Firmware updates (if released) are delivered via USB-to-serial adapter and require technician-level access—ensuring configuration stability during regulatory audits.

Applications

• Pre-occupancy IAQ verification in newly constructed or renovated civil buildings per GB 50325 compliance mandates.
• Source identification and emission profiling of formaldehyde-emitting materials (e.g., plywood, particleboard, insulation).
• Time-weighted average (TWA) exposure assessment for ammonia in HVAC maintenance zones or cleaning product storage areas.
• Baseline TVOC characterization in office spaces, schools, and hospitals to inform ventilation strategy optimization.
• Quality assurance sampling during third-party IEQ certification (e.g., LEED IEQ Credit 3.2, WELL Building Standard A01).
• Field validation of sorbent tube recovery efficiency studies under controlled flow conditions.

FAQ

Does the BQHL-II/IV require external calibration before first use?
Yes—users must perform initial flow calibration using a NIST-traceable primary standard (e.g., bubble meter or electronic calibrator) prior to regulatory sampling. Calibration certificates should be maintained per GB 50325 Clause 6.0.4.
Can the instrument operate while charging?
No—battery charging and sampling are mutually exclusive functions to preserve measurement stability and prevent electrical noise interference.
Is the LCD display readable under direct sunlight?
The high-contrast, backlit monochrome LCD ensures legibility in ambient light up to 10,000 lux; no additional shading accessories are required for typical indoor or shaded outdoor use.
What maintenance intervals are recommended?
Motor brushes and inlet filters should be inspected every 200 operating hours; full recalibration is advised semiannually or after any impact event affecting mechanical integrity.
Are spare parts and service support available internationally?
Original equipment manufacturer (OEM) technical documentation, replacement pumps, and flow sensors are supplied globally through authorized distribution partners—with lead times typically 4–6 weeks ex-warehouse Jiangsu.