Description
System Architecture & Operational Principle
The 85UVF1-1QDK3 is a field-mounted ultraviolet flame scanner with an integral amplifier and a K3-style electrical connector, designed for secure, weatherproof connections in industrial combustion applications. It operates at Level 0 (Process) of the Purdue Model, interfacing directly with burner management systems (BMS) or safety-rated PLCs that control fuel valve actuation and combustion safeguarding.
Upstream, the BMS initiates ignition sequences and monitors the 4–20 mA output from the 85UVF1-1QDK3 to confirm flame establishment. The scanner detects UV radiation in the 190–260 nanometer range, characteristic of hydrocarbon combustion, and amplifies the signal internally to drive a proportional 4–20 mA current loop. This signal is interpreted by the BMS to either continue normal operation or execute a safety shutdown (fuel cut-off) upon flame loss.
The K3 connector provides a threaded, IP66-rated connection for power and signal leads, reducing the risk of water ingress or wire pull-out in high-vibration environments. The integral amplifier eliminates the need for external signal conditioners, simplifying wiring and reducing potential failure points. The NEMA 4 housing protects against dust, moisture, and corrosion, making it suitable for outdoor boiler houses, turbine enclosures, and process heater applications.
FIREYE 85UVF1-1QDK3
Core Technical Specifications
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Physical Interface: K3-style connector (IP66 rated) with 3-conductor shielded cable (18–22 AWG)
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Signal Type: 4–20 mA current loop (proportional to flame intensity)
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Detection Spectrum: 190–260 nm UV wavelength
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Response Time: <1 second for flame detection; <3 seconds for flame failure recognition
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Operating Temperature: -40°C to +75°C (-40°F to +167°F)
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Environmental Rating: NEMA 4 (IP66 equivalent) weatherproof enclosure
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Supply Voltage: 24 VDC nominal (18–32 VDC range)
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Current Draw: 20 mA (no flame) to 100 mA (full flame) typical
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Field of View: ~100° cone angle (line-of-sight dependent)
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Electrical Connection: K3 connector with screw-lock mechanism; pre-wired pigtails available
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Certifications: FM approved, CSA certified, CE marked
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Weight: ~1.2 kg (2.6 lbs)
Customer Value & Operational Benefits
Secure, Weatherproof Connectivity with K3 Connector
The K3-style connector provides a threaded, vibration-resistant seal that prevents water and dust ingress, even in high-humidity or washdown environments. This is critical for outdoor installations or areas with frequent thermal cycling, where loose connections can lead to signal loss or false trips.
Simplified Wiring and Reduced Failure Points
The integral amplifier design removes the need for an external signal conditioning unit, cutting installation time and eliminating a potential failure point. This is particularly valuable in retrofits where space is limited and additional components would complicate panel layouts.
Noise-Resistant Signal for Long Cable Runs
The 4–20 mA output signal is inherently immune to electrical noise and voltage drops over distance, allowing reliable communication with BMS panels located hundreds of feet away. This ensures accurate flame status reporting even in electrically noisy environments like turbine halls or refinery process units.
FIREYE 85UVF1-1QDK3
Field Engineer’s Notes (From the Trenches)
When terminating the 85UVF1-1QDK3 with a K3 connector, torque the gland nut to the manufacturer’s spec—usually 15–20 in-lbs. I’ve seen installers overtighten, cracking the connector body, or undertighten, allowing moisture to seep in and corrode the contacts. Also, use heat-shrink tubing over the cable entry to prevent water wicking up the wire insulation. If you’re replacing an older Fireye scanner without a K3 connector, you’ll need a compatible K3 pigtail adapter—don’t try to splice the cable directly into the scanner housing, as this voids the IP rating.
Real-World Applications
In a natural gas-fired combined-cycle power plant, the 85UVF1-1QDK3 is mounted on the combustion liner of a 200 MW gas turbine. The scanner’s 4–20 mA output feeds the turbine control system, which requires a minimum 8 mA signal to confirm flame stability before increasing fuel flow. The K3 connector’s secure seal withstands the turbine’s high vibration and temperature cycles, ensuring reliable operation during base-load and peaking modes.
On a petrochemical refinery’s fired heater, the 85UVF1-1QDK3 monitors the flame in a multi-burner furnace. The scanner is positioned to view the primary combustion zone of each burner, with the 4–20 mA signal indicating individual burner flame status. The BMS uses this data to implement staggered ignition sequences and to shut down specific burners if flame is lost, maintaining process continuity while ensuring safety. The K3 connector’s IP66 rating protects against the refinery’s corrosive atmosphere and occasional washdowns.
