Nexisense Infrared Flame Sensor: Industrial-Grade Pyroelectric Flame Detection and System Integration Solutions

Core Technical Advantages of Pyroelectric Infrared Flame Sensors

Pyroelectric flame sensors are based on the Pyroelectric Effect, converting temperature transients caused by flame radiation into surface charge changes, which are then converted into measurable voltage signals through pre-amplification. The Nexisense RPFA series uses lithium tantalate (LiTaO₃) single crystal as the sensing element, with Curie temperature >600℃ and excellent temperature stability of pyroelectric coefficient (high response consistency in 1–20 μm range, temperature drift rate only 1–2‰), combined with narrow bandpass filter window (typical center wavelength 4.3 μm, FWHM ±0.1 μm), effectively locking the CO₂ characteristic radiation peak of combustion products while suppressing interference from sunlight, fluorescent lamps, and hot body backgrounds.

Typical Performance Parameters:

• Spectral Response: 3.8 μm, 4.3 μm, 4.4 μm, 4.48 μm, 5.0 μm optional

• Detection Distance: With standard field of view >115°, 1 m² n-heptane standard fire source ≥30 m

• Response Time: T90 ≤ 5 s (standard flame)

• Power Consumption: Standby<100 μA (voltage mode)

• Microphonic Effect: Extremely low (vibration resistant)

• Explosion-Proof Rating: Ex d IIC T6 Gb / Ex ia IIC T4 Ga

• Operating Temperature: -40℃～+85℃ (industrial grade)

Compared with UV/UV-IR composite types, the pyroelectric solution has no blind spots, no need for periodic self-test light source attenuation, and stronger robustness in dirty/oily mist environments, especially suitable for long-term continuous operation in industrial fixed monitoring.

Main Application Scenarios and Engineering Project Practices

Petrochemical Storage Tank Areas and Hazardous Chemical Warehouses
Deployed on dome roofs, outside fire dikes and between valve groups to achieve multi-angle blind-spot-free coverage. 4–20 mA / RS485 output connects to SIS safety instrumented system, with dual-band confirmation logic set (4.3 μm main signal + reference channel background suppression); when fire source radiation exceeds preset threshold (typically 10–30 kW/m²), it triggers linked sprinkler, feed valve cutoff, and water cannon activation. In a large refining enterprise storage tank farm project, the Nexisense 4.3 μm sensor array controlled average alarm response time to<8 s with false alarm rate <0.5 times/year.

Power Generation Facilities and Boiler Rooms
Installed around oil/gas boilers and key nodes of coal conveying trestles, combined with explosion-proof pan-tilt for 360° scanning. Flame signal combined with temperature/combustible gas judgment, connected to DCS to trigger MFT (main fuel trip) and CO₂ fire extinguishing system. Actual case shows that in the renovation of coal conveyor belt corridor in a coal-fired power plant, the sensor effectively captured belt friction sparks, linking sprinkler and shutdown 30–60 s in advance, preventing fire spread along the coal seam.

Printing/Coating Workshops and Paint Warehouses
For flammable environments with solvent volatile organic compounds (VOCs), 5.0 μm filter window version is selected to reduce organic vapor background interference. Modular design facilitates integration into workshop ventilation interlock and local dry powder fire extinguishing devices. In a certain automotive coating line project, Nexisense sensors and UV/IR composite detectors were redundantly configured to achieve reliable response to open flames in spray booths within<6 s.

Charging Stations and New Energy Sites
Battery thermal runaway early features include open flame/incandescent radiation. Nexisense sensors are installed on top of the pile or inside group pile protective covers, outputting dry contact signals to link power cutoff, fire sprinkler and remote alarm. In a large-scale charging station project of a certain operator, the 4.3 μm sensor successfully issued early warning 10–20 s before thermal runaway ignition, combined with smoke-temperature composite algorithm to control false alarm rate at extremely low level.

Selection Guide and System Integration Considerations

Selection Key Parameters

• Band Selection: 4.3 μm preferred for hydrocarbon flames, 5.0 μm suitable for alcohol/ether solvent environments, 3.8 μm can cover some flameless combustion

• Field of View and Detection Distance: >115° large FOV suitable for close-range dense deployment, narrow FOV + long-focus lens for 30–50 m long distance

• Output Interface: 4–20 mA (two/three-wire) + relay dry contact as industrial standard, digital RS485/Modbus RTU convenient for networking

• Explosion-Proof Type: Ex d flameproof for Zone 1 areas, Ex ia intrinsically safe for portable/wireless nodes

• Power Supply and Consumption: Supports 12–30 Vdc wide voltage, standby<100 μA version suitable for solar-powered scenarios

System Integration Considerations

• Installation Height and Angle: Recommended 2.5–4 m height, avoid direct view of strong light sources or hot bodies; when multi-detector deployment, main optical axis overlap rate ≥30%

• Background Suppression: Enable reference channel algorithm to automatically track environmental radiation baseline and suppress sunlight/hot reflection interference

• Signal Processing: Recommended dual-band or triple-band confirmation logic (flame main signal + background suppression + duration filter >3 s)

• Electromagnetic Compatibility: RS485 bus with shielded twisted pair + 120 Ω terminating resistor, away from frequency converters/high-power motors

• System Commissioning: Use standard n-heptane fire pan for multi-distance, multi-angle testing, establish on-site environment compensation table; recommend functional verification every 6 months

  
  

OEM Customization and Bulk Supply Advantages

Nexisense provides OEM/ODM services from single sensors to complete flame detection modules, supporting:

• Custom specific band filters (center wavelength ±0.05 μm accuracy)

• Field of view and detection distance optimization (custom Fresnel/reflector combination)

• Interface and protocol adaptation (Modbus, HART, LoRa, 4–20 mA+HART)

• Joint design of explosion-proof housing and mounting bracket

• Brand labeling, serialization management and traceable supply chain

Bulk supply capability covers thousands to tens of thousands of points projects, delivered in batches according to engineering milestones, with tiered pricing, priority stocking and joint environmental reliability testing. Long-term partners can participate in next-generation multi-spectral fusion or AI-assisted flame recognition algorithm development.

Frequently Asked Questions (FAQ)

1. What are the main advantages of Nexisense pyroelectric flame sensor compared to ultraviolet type?
      No need for periodic self-test light source, no blind spots, stronger robustness against oil mist/dust, lower false alarm rate, especially suitable for heavily contaminated industrial sites.

2. How to ensure flame detection reliability in strong direct sunlight environments?
      Using 4.3 μm narrowband filter + reference channel background suppression algorithm can suppress sunlight interference to<1%; add sunshade or optimize installation angle if necessary.

3. How consistent is the sensor response to flames of different fuels?
      Lithium tantalate single crystal has flat response in 1–20 μm range, good response to hydrocarbon, alcohol, hydrogen and other flame radiation, error <±10% after calibration.

4. How to achieve multi-detector networking and centralized management in explosion-proof areas?
      Supports RS485 Modbus RTU networking (up to 32 nodes/segment), with explosion-proof isolator or intrinsically safe gateway connected to host computer for centralized monitoring and remote parameter configuration.

5. How does the sensor perform in terms of zero drift under high and low temperature cycling environments?
      High Curie temperature of lithium tantalate, zero drift <±2% in -40～+85℃ range, combined with built-in temperature compensation algorithm, annual drift <±3%.

6. What is the minimum order quantity and lead time for OEM custom specific band filters?
      Standard bands start at 500 pcs, custom center wavelength/bandwidth projects usually start at 2000 pcs, development cycle 8–14 weeks.

7. How to seamlessly interface with existing SIS safety instrumented systems?
      Provides 4–20 mA+HART output or relay dry contact, supports SIL2/3 safety loop design, can be directly connected to SIS logic solver.

8. How to achieve blind-spot-free flame coverage in large-space warehouses?
      Recommend large field of view (>115°) models + reasonable grid deployment (single detector coverage radius 20–30 m), combined with pan-tilt inspection or multi-detector overlap to ensure blind area<5%.

9. Does bulk supply provide per-batch consistency reports and third-party explosion-proof certification?
      Yes, provides factory spectral response and response time batch test reports, supports IECEx/ATEX third-party re-inspection and reports.

10. For oil and gas receiving station projects, what is the recommended flame detector response time and linkage delay control?
       Sensor T90<5 s, total system response time (including communication and logic processing) controlled within <10 s, linkage to fire water cannon/foam system delay <15 s.

Conclusion

Nexisense focuses on providing high-reliability infrared flame detection solutions for petrochemical, hazardous chemical, power, warehousing, fire engineering integrators and equipment manufacturers. If your company needs sensor selection, system architecture design, explosion-proof certification support or OEM custom development in flame monitoring system new construction/renovation projects for hazardous chemical parks, storage tank areas, power generation facilities, coating workshops or new energy sites, welcome to contact us for in-depth communication on specific requirements and cooperation paths. Let us jointly build a more reliable industrial fire early warning system to protect production and life safety.