The Performance of a Flammable Gas Sensing Pellister Bead with Respect to the Material Properties of the Support Arm

The pellistor bead is used for the detection of combustible gases within an oxygen-based atmosphere. In its simplest form a platinum wire coil is encapsulated within a porous alumina bead – which has been doped with a precious metal such as palladium or rhodium – and is suspended between two metallic support arms. This paper looks at the performance of this device with respect to the material properties of these support arms. A three-dimensional finite element model was constructed using ANSYS software. It shows how the efficiency of this device can be improved by careful choice of the materials used for the support arms. In many cases gas sensors employing pellistor beads have to be portable. Any increase in the pellistor’s efficiency would result in either longer battery-lifetime or in the reduced mass of the complete sensing unit.

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