Abstract: Apparatus for removing moisture such as oil and water vapor from compressed gases such as air with less decrease in pressure by conventional filter means by providing a relatively coarse annular filter to condense the major portion of such moisture by gases passing downward therethrough to afford drainage of condensate by gravity before the gases pass upward through coaxial interior desiccant filter means to remove any residual moisture before the moisture free gases are discharged from the upper end of the desiccant filter means. The coarse filter is contained between transparent outer and inner containers and the desiccant filter means is contained within the transparent inner container so as to extend upwardly above the upper end of the coarse filter such that the condition of both the coarse filter and desiccant filter means is visually observable.

Abstract: Inserted lineally in the output line of an oxygen supply apparatus between the regulator and the humidifier is a moisture trap. This captures moisture borne by a reverse flow of liquid from the humidifier produced by a vacuum occuring in the regulator when the apparatus is shut down and thereby protects minute oxygen flow orifices in the apparatus from impairment by calcification.

Abstract: This invention relates to apparatus for periodically automatically purging the contaminants from a filter unit of a compressed air system to reactivate the filtering medium in the filter unit during the time that an air compressor for supplying air under pressure to the system is operating unloaded or is stopped.