Schütz FLOWEVO Fumigant Gas Sensor

Overview

The Schütz FLOWEVO Fumigant Gas Sensor is a high-integrity, dual-beam non-dispersive infrared (NDIR) detection module engineered specifically for continuous, quantitative monitoring of fumigants—primarily methyl bromide (CH₃Br) and sulfuryl fluoride (SO₂F₂)—in industrial quarantine, phytosanitary treatment, cold storage, and structural fumigation applications. Unlike electrochemical or catalytic bead sensors, the FLOWEVO leverages the fundamental spectroscopic property that each gas exhibits unique absorption bands in the mid-infrared region—its molecular “fingerprint.” By employing a reference and measurement channel within a single optical path, the dual-beam NDIR architecture inherently compensates for lamp aging, dust accumulation, and minor optical misalignment, delivering long-term stability without recalibration drift. The sensor operates on pump-suction sampling with active flow control (0.1–1.0 L/min), integrated chamber temperature stabilization, and real-time pressure compensation—ensuring metrological consistency across variable ambient conditions. Its solid-state optical design eliminates moving parts, chemical reagents, or reactive surfaces, resulting in intrinsic resistance to poisoning, corrosion, or mechanical wear.

Key Features

• Target-specific NDIR optics optimized for CH₃Br (at ~11.9 µm) and SO₂F₂ (at ~8.8 µm), enabling high selectivity and minimal cross-sensitivity to CO₂, H₂O, CH₄, or common VOCs
• Dual-beam photometric architecture with thermally stabilized IR source and matched pyroelectric detectors for inherent zero and span stability
• Active heating of the measurement chamber to prevent condensation and suppress humidity-induced baseline shifts—critical in high-RH fumigation enclosures
• Anodized aluminum housing with IP65-rated ingress protection, designed for mounting in controlled-environment chambers, recirculation ducts, or portable fumigation monitors
• Modular interface architecture: native TTL-level digital output with auto-baud Modbus ASCII RTU; optional analog outputs (4–20 mA, 0–10 V) via FLOWEVO plus controller
• Low-power operation (<800 mW without heater) compatible with battery-backed or 24 V DC industrial control systems
• Calibration-free operational life exceeding 10 years under typical fumigation duty cycles (per ISO 17025 traceable validation protocols)

Sample Compatibility & Compliance

The FLOWEVO is validated for use with dry, particle-free air streams containing up to 95% relative humidity (non-condensing) and operating pressures between 800–1200 mbar. It is not intended for direct exposure to liquid condensate, aerosolized phosphine, or chlorine-based fumigants. Sample conditioning (e.g., particulate filtration, desiccation) is recommended when inlet gas contains oil mist, heavy hydrocarbons, or submicron particulates. The sensor complies with IEC 61000-6-2 (immunity) and IEC 61000-6-4 (emissions) for industrial environments. While not intrinsically safe certified, it may be deployed in Zone 2/Class I Division 2 areas when housed in appropriate enclosures per ATEX/IECEx guidelines. Data integrity meets GLP-aligned requirements: all internal compensation algorithms (temperature, pressure, zero drift) are deterministic and auditable; firmware logs timestamped diagnostics for FDA 21 CFR Part 11-compliant systems when paired with FLOWEVO plus controller.

Software & Data Management

The FLOWEVO communicates via ASCII-based Modbus RTU over TTL serial, supporting seamless integration into SCADA, BMS, or custom LabVIEW/Python acquisition platforms. The FLOWEVO plus controller adds local data logging (SD card), configurable alarm thresholds (pre-set or user-defined), relay outputs for ventilation interlocks, and USB/RS485 gateway functionality. All concentration outputs are compensated values—derived from raw absorbance ratios, corrected using factory-characterized thermal and barometric coefficients stored in onboard EEPROM. No proprietary drivers or cloud dependencies are required. Firmware updates are performed via UART using open-standard hex files, ensuring full traceability and version control in regulated environments.

Applications

• Real-time residual fumigant monitoring during post-treatment aeration in grain silos, shipping containers, and timber treatment chambers
• Process validation and leak detection in SO₂F₂-based structural fumigation (e.g., termite eradication in commercial buildings)
• Automated dose verification in methyl bromide quarantine treatments for imported horticultural commodities (aligned with ISPM 18 and NPPO requirements)
• Integration into fumigation safety interlock systems—triggering alarms or halting chamber pressurization upon threshold exceedance
• Long-term environmental compliance logging for EPA FIFRA reporting and phytosanitary certificate generation

FAQ

What gases does the FLOWEVO sensor detect?
It is factory-calibrated for methyl bromide (CH₃Br) and sulfuryl fluoride (SO₂F₂). Custom calibration for other IR-active gases (e.g., CO₂, SF₆) is available upon request.
Is field calibration required?
No routine field calibration is needed. The sensor’s dual-beam architecture and built-in thermal/pressure compensation maintain accuracy within ±1% FS for ≥12 months. Optional zero-span verification using certified gas standards is recommended annually for audit readiness.
Can the FLOWEVO operate in high-humidity environments?
Yes—its actively heated measurement chamber and humidity-compensated algorithm enable stable operation up to 95% RH (non-condensing). Condensate must be removed upstream.
What is the minimum detectable concentration?
The limit of detection is ≤1% full scale (FS), corresponding to ~1 ppm for CH₃Br (100 ppm FS range) or ~0.1 ppm for SO₂F₂ (10 ppm FS range), per ISO 11355-1 precision criteria.
How is the sensor powered and interfaced in an existing control system?
It accepts 3.3–6 V DC for standalone operation with TTL serial output. For analog integration or advanced control, the FLOWEVO plus controller provides 24 V DC input, 4–20 mA output, relay contacts, and RS485 Modbus TCP bridging.