Abstract: The present invention relates to a gas detector cell unit comprising a gas cell, the unit comprising an outer housing providing access to the gas outside through a protecting filter adapted to making gas cell safe for use in explosive environments, i.e. a sintered filter, and the unit comprising means for detecting reduction in the circulation through said protecting filter.

Abstract: The present invention relates to a gas detector cell and cell unit for optical detection of a predetermined gas, the cell being provided with optical means for investigating a gas sample present in the cell. The cell is constituted by a volume enclosed in a container, at least part of the container wall being constituted by a membrane, the membrane being provided with openings allowing diffusion of gas therethrough, and the membrane openings being provided with a catalyst for converting the gas diffusing therethrough to said predetermined gas.