Swing back whizzer blades for mechanical air separator

Claim 1

In a mechanical separator comprising an upright casing, means for causing a forward axial flow through the casing of gas entraining solids to be separated therefrom, an assembly mounted centrally within the casing including an inner imperforate member having an outer circular periphery, said imperforate member having a vertical axis corresponding to that of the casing, means for rotating the imperforate member, a plurality of upright means secured to the upper surface of the imperforate member, a plurality of radially extending blades, each blade being pivotally connected to one of the upright means so as to be pivotable, vertically about its pivot point, each blade having a major portion on one side of its pivot point, and a minor portion on the other side of its pivot point, each blade being pivotally connected to its respective upright means high enough above the upper surface of the imperforate member so it can be pivoted through at least a 180* arc, the length of the major portion of each blade being such that the end of the major portion rests on the upper surface of the imperforate member when it is positioned inwardly of its pivot point, each blade also being pivotally connected high enough above the upper surface of the imperforate member so that the center of gravity of the major portion of the blade is below its pivot point while the end of the major portion is in contact with the upper surface of the imperforate means, so that centrifugal force tends to hold it in a stationary position once it is initially positioned with the major portion extending inwardly, and centrifugal force will also tend to hold the blades in a stationary horizontal position if they are initially positioned with the major portion extending outwardly of the pivot points.