| 摘要 |
The invention concerns a method for separating, by impaction, living particles and particles capable of being revived of a gas or a gas mixture under pressure, characterised in that it comprises a step (a) which consists in accelerating in a stage and along an axis (x) a single gas or gas mixture stream in a confined volume (V), to reach a speed not less than the speed of sound; a step (b) which consists in sudden deceleration of said single stream derived from step (a) in said volume, along substantially the same axis (x), at atmospheric pressure; a step (c) which consists in changing the direction of the gas or gas mixture flow at the output of the volume (V), which on average becomes radial; and a step (d) which consists in trapping said particles separated from the flow during step (c), on a target. In another embodiment, the method further comprises a step (e) which consists in counting the particles trapped during step (d). The invention also concerns a method for determining the microbiological quality of a gas under pressure, characterised in that it consists in using said alternative embodiment. The invention further concerns a device (D) designed to implement said method and its alternative embodiment comprising an element (D1) wherein the single gas stream is successively subjected to steps (a) and (b), an element (D2) constituting the target whereon the living particles or particles capable of being revived are trapped as in step (d), and securing means for making (D1) and (D2) integral, while allowing the flow of gas or of gas mixture to change direction as in step (c). The device is useful for determining the microbiological quality of a gas under pressure.
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