55UV5-1009 Fireye Scanner

APPLICATION

Fireye 55UV5 self-checking scanners are used to detect ultraviolet emissions from fossil fuel flames such as natural gas, coke oven gas, propane, methane, butane, kerosene, light petroleum distillates and diesel fuels and are suitable for use in Class I, Div. 2, Groups A, B, C, D and Class II, Div. 2 Groups F and G hazardous locations. These 55UV5 models are used only with the BurnerLogix, Flame-Monitor, D-Series, FlameWorx and MicroM control models to provide flame safeguard and monitoring systems for supervised manual, semi-automatic and fully automatic single burner boilers, process ovens and heaters.

PRINCIPLES OF OPERATION

The 55UV5 scanners use a UV-eye detector. This detector is a sealed, gas filled, UV-sensitive tube containing two electrodes connected to a source of AC voltage. When UV radiation of sufficient energy falls upon the electrodes, electrons are released and the inter-electrode gas becomes conductive, resulting in an electric current flow from one electrode to the other. The current flow starts and ends abruptly and is known as an “avalanche.”

A very intense source of UV radiation will produce several hundred avalanches or pulses per second. With less radiation there will be fewer pulses per second. Upon total disappearance of flame, the detector output ceases. Thus, the presence or absence of pulses is an indication of the presence or absence of flame; the frequency of the pulses is a measure of flame intensity. Pulses generated by the scanner are transmitted to a compatible Fireye control via scanner wiring.

FEATURES

The components are contained in a cast aluminum NEMA 4X, IP66 housing sealed with an oil-resistant gasket. The quartz lens is a planoconvex design, resulting in increased sensitivity. Also included in the scanner is an electromagnetic shutter that permits a self-checking circuit to verify that the scanner and signal circuits are producing valid flame presence or absence information. During the shutter closed period, the detector’s optical path is blocked from flame radiation, allowing the control system to verify the proper operation of the ultraviolet tube. While the shutter is open, flame presence or absence is detected.