Fireye InSight II Marine Flame Scanner

InSight II Marine Flame Scanner Complete Technical Manual: Dual Sensor Explosion proof Design and Field Engineering Application

In the safety control of marine boilers, offshore platform burners, and various industrial combustion systems, flame detection devices are the "eyes" of combustion management systems. Traditional flame scanners typically consist of independent detection heads, amplifiers, and flame switch modules, with complex wiring and numerous fault points. The InSight II series marine flame scanner (model 95DSS3-1CEXSS) launched by Fireye adopts an integrated design, which integrates flame detection, signal amplification, safety judgment, and flame switch functions into one detection head, and can directly interface with the main combustion management system (BMS) without the need for external amplifiers. This article systematically introduces the dual sensor principle, explosion-proof structure, installation and purging requirements, electrical wiring, parameter configuration, and on-site troubleshooting methods of the scanner from an engineering and technical perspective, helping ship electrical engineers and combustion safety technicians fully utilize equipment performance.

Product positioning and core features

The InSight II Marine Scanner is designed for harsh marine environments, featuring a 316 stainless steel casing with IP66 protection rating and ATEX Ex db IIC T6~T4 explosion-proof certification. Its most prominent feature is its dual sensor architecture: it includes both ultraviolet (UV) and infrared (IR) detectors, which can select the most suitable detection method based on the fuel type (oil, gas, or mixed fuel) and combustion conditions.

Compared with the split flame detection system, InSight II integrates signal conditioning, threshold comparison, relay output, and analog signal output all inside the scanning head. Users only need to provide a 24V DC power supply to directly obtain two independent flame relay contacts, two 4-20mA flame intensity analog signals, and one fault relay output. This integrated design significantly reduces the number of amplifier modules inside the cabinet, simplifies the wiring of the ship's engine room, and reduces the complexity of spare parts inventory.

List of core features:

Dual detectors: UV and IR, can be used independently or in combination

Two independent adjustable flame relays (FR1, FR2), each capable of selecting logic from UV, IR, or both

21 modulation frequency selections (used to distinguish target flames from background flames)

Adjustable sensor gain and relay engagement/release threshold

Two 4-20mA analog outputs (corresponding to the flame intensity of FR1 and FR2)

Fault relay (for self diagnostic alarm)

Four programmable memory files (applicable to different fuels or load rates)

Auto Config and manual override function

Remote communication: via Fireye Explorer PC software (optional)

VFD display screen and keyboard (on-site parameter viewing and modification)

316 stainless steel shell, IP66，ATEX Ex db IIC T6/T5/T4，Ex tb IIIC

Dual sensor technology and frequency selection

2.1 Ultraviolet Sensor (UV)

UV sensors are sensitive to the ultraviolet radiation emitted by flames (usually in the wavelength range of 190-270nm), have a fast response speed, and are insensitive to high-temperature thermal radiation (infrared). Therefore, they can effectively distinguish flames from backgrounds such as burning refractory bricks and furnace walls. The advantage of UV sensors is that they are not affected by high-temperature solid radiation inside the furnace, but the disadvantage is that they may respond incorrectly to external ultraviolet sources such as welding arc light and lightning, and may have insufficient sensitivity to certain low ultraviolet radiation flames (such as low NOx burners).

2.2 Infrared Sensor (IR)

IR sensors are sensitive to the infrared radiation unique to flames (typically in the wavelength range of 1.0~3.5 μ m) and can detect the combustion characteristics of carbon containing fuels. IR has a certain inhibitory effect on high-temperature background, but not as thorough as UV. In some burners that use heavy oil or crude oil, IR signals are often more stable than UV signals.

2.3 Dual sensor collaborative work

InSight II allows users to independently select signal sources for each flame relay:

Only UV: The relay action is based on the radiation intensity detected by the UV sensor.

Only IR: based on IR sensors.

UV+IR (logical AND): When two sensors detect flames simultaneously, it is considered as fire, improving safety.

UV/IR (logical OR): If any sensor detects a flame, it is considered as fire and improves availability.

In marine boilers, when switching from fuel oil to gas, the flame radiation characteristics of the two fuels are different. Users can use four programmable files to pre store the optimal settings (gain, frequency, threshold) for two fuels, and achieve one click adaptation through external signals or manual file switching.

2.4 Modulation frequency selection

Flames flicker at a specific frequency (depending on the aerodynamics of the burner and the fuel injection method), while background radiation is typically direct current or at different frequencies. InSight II offers 21 modulation frequency options (typically ranging from 20 to 1000Hz), allowing users to set the scanner to only respond to signals that are consistent with the target flame flicker frequency, thereby suppressing interference from adjacent burners or reflected light. Choosing the right frequency is a key step in improving the signal-to-noise ratio.