a rotary device including a plurality of vertical prismatic sectors mounted on a first annular plate comprising two arrays of gas passages which communicate with the outer and inner collectors of respective sectors , and interacting with a second plane annular plate on a housing defining a set of inner chambers . the second plate comprises two concentric arrays of apertures which communicate with corresponding chambers in the set of chambers , and are spread out along the path of the two gas passage arrays of the first plate . the device is particularly useful for producing oxygen .