Impactor and method for characterizing a carrier gas enriched with suspended particles

A method for characterizing a carrier gas enriched with suspended particles, comprising providing an impactor (1) for analysis of a carrier gas enriched with suspended particles, the impactor including a classifying nozzle unit (3) having at least one classifying nozzle (2) and with just one impact plate (7), the impact plate (7) being formed as a resonantly oscillating, mass-sensitive element (7, 33) and the resonantly oscillating, mass-sensitive element (7, 33) being secured in an impact plate holder (8), the impact plate holder (8) is arranged to be movable in relation to the classifying nozzle (2) by a motor (12), so that a point of impingement (35) of the carrier gas enriched with suspended particles on the impact plate (7) migrates along an arc of a circle or along a circle, a center point coinciding with an axis of a rotating or pivoting movement, on the impact plate (7) and a depositing location of the suspended particles on the resonantly oscillating, mass-sensitive element is changeable during a depositing process, the point of impingement being guided by relative movement along a line of constant mass sensitivity, the resonantly oscillating, mass-sensitive element (7, 33) is electrically connected to a flexible connecting cable (24) that is dimensioned such that the rotating or pivoting movement of the impact plate holder (8) is made possible within a prescribed rotating or pivoting range, and the impact plate holder (8) has a holding plate (17) on which the resonantly oscillating, mass-sensitive element (7, 33) is held, and the impact plate holder (8) has resilient contact pins (23) that are arranged regularly, which in a position for use, act uniformly on the holding plate (17);

• conducting the carrier gas enriched with suspended particles in the impactor (1) through the classifying nozzle (2) onto the resonantly oscillating, mass-sensitive element (7, 33) such that, as from a prescribed mass, suspended particles are deposited in a depositing process on the resonantly oscillating, mass-sensitive element (7, 33), and determining a mass of the suspended particles deposited on the resonantly oscillating, mass-sensitive element (7, 33) electronically at least one of during the depositing process or between two depositing processes, passing electrical signals at least one of from or to the resonantly oscillating, mass-sensitive element (7, 33) by way of a connecting cable (24), moving the resonantly oscillating, mass-sensitive element (7, 33) in relation to the static classifying nozzle (2) during the depositing process, so that a point of impingement (35) of the carrier gas enriched with suspended particles on the impact plate (7) migrates along the arc of the circle or along the circle, with the center point coinciding with the axis of a rotating or pivoting movement of the impact plate (7), on the impact plate (7) and changing the depositing location of the suspended particles on the resonantly oscillating, mass-sensitive element during the depositing process, the point of impingement being guided by the relative movement along the line of constant mass sensitivity, and at least one of during the depositing process or between two depositing processes, transversely displacing the point of impingement (35) of the carrier gas conducted through the classifying nozzle (2) on the resonantly oscillating, mass-sensitive element (7, 33) in relation to the line of constant mass sensitivity (34).