PrimePell Oil Industry Infrared Methane Sensor Description and Operation

The PrimePell sensor uses the non-dispersive infrared method to detect the presence of hydrocarbon gases. The sensor contains an infrared radiation source, a dual element custom infrared detector, a unique optical waveguide into which gas diffuses and internal ARM7 core microprocessor based electronics to provide a voltage output which is independent of the power supply polarity. The sensors can be configured to provide a pellistor format output, typically mid supply at zero with the voltage output increasing with respect to the detector pin by 100mV at range, or a linear voltage output, typically 0.4V – 2.0V over range with respect to the negative supply pin. Inaddition, the output can be read and the internal configuration can be accessed by a serial communications link.The communication link contacts are pads in the 3 pin version PrimePell and pins in the 5 pin version PrimePell.The internal electronics perform all the functions of driving the optical parts of the sensor, extracting the detectorsignals, converting the signals to a concentration, applying temperature compensation and scaling the output.When in a pellistor configuration, the PrimePell can replace catalytic sensors in existing circuitry subject to thepower supply  requirements.  External components will be required to meet the power supply requirement when a PrimePell is used in constant current pellistor circuitry. The PrimePell is not currently Ex approved so should behoused in a suitable Ex enclosure when used in Hazardous areas.

PrimePell Oil Industry Infrared Methane Sensor Features

• Operates independent of supply polarity, as a pellistor
• Pellistor mimic Bridge output
• Voltage rises across detector connections in gas, as a pellistor
• Relative responses to key hydrocarbons are similar to a pellistor
• Operating voltage range 3.0V - 5.0V
• Operating current 80mA typical
• Latest technology MEMS detectors
• Sensing ranges: 0-100% LEL Methane, 0-100% LEL Hydrocarbons or 0-100% Volume Methane
• All metal construction with isolated housing
• Small internal volume
• Flexible electronic configuration access
• User calibration also enabled by hardware connections
• Wide operating temperature range
• Fast response
• Immunity from ‘poisoning’

PrimePell Oil Industry Infrared Methane Sensor Specification
Unless otherwise stated all data was taken using: Supply voltage of 3.5V. Ambient temperature (between 20°C and 25°C). Ambient pressure (between 995 hPa and 1020 hPa). Gases diluted in nitrogen. Gas Flowrate 1litre/min across sensor face.