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AssigneeThe McCarter Corporation
InventorsLouis N. McCarter, III, W. Robert Deemer, Robert G. Meeker, Harry B. Weaver, John W. Smith
Estimating the term…
In a continuous drum mix asphalt plant, dust is exhausted from an intermediate zone of the drum mixer between its drying and mixing zones. The dust is exhausted radially through openings into a collection housing, which communicates with a dust collector and exhaust blower. An end housing at the discharge end of the drum communicates with the same dust collector and blower. Dampers are provided to control the relative proportion of air exhausted from the drum through the respective housings. Aggregate deflectors on the interior wall of the drum at the intermediate zone allow air and dust to flow while inhibiting the flow of aggregate. The collection housing surrounding the intermediate zone is of a size such as to produce a reduction in the velocity of the air as it passes out of the drum. Consequently, it serves as a knock-out box for the collection of larger particles which are carried out of the drum, but which settle out of the air stream as a result of the velocity decrease. These collected particles are reintroduced into the drum by scoops on the exterior of the drum. These scoops are also used for the introduction of recycled asphaltic concrete.
A method of preparing asphaltic concrete comprising introducing aggregate into a rotating drum, exposing the aggregate to heat in a first zone of said drum to effect drying of the aggregate while in said first zone, causing the aggregate to move to a second zone of the drum, introducing asphalt into the second zone of the drum, mixing the aggregate with asphalt in the second zone, and drawing air axially through said drum in the direction from said first zone toward said second zone, and characterized by the steps of drawing air from a third zone in said drum located between said first and second zones, drawing suspended particles produced in the drying step out of said drum along with the air drawn from said third zone, and at least temporarily isolating the suspended particles and air drawn out of said drum from said third zone from the asphalt and aggregate in said second zone.
Apparatus for making asphaltic concrete comprising a hollow drum, having an inlet end and a discharge end, means for rotating the drum about its longitudinal axis, the drum having a drying zone extending inwardly from the inlet end, a mixing zone extending inwardly from the discharge end and a third zone located between the drying and mixing zones, burner means for directing a flame into the drying zone, means for lifting aggregate material in the drying zone and dropping the material so lifted downwardly through the area heated by the flame for removal of moisture, means for introducing asphalt into the mixing zone, means for effecting flow of dried aggregate from the drying zone to the mixing zone, means for effecting mixing of the aggregate and asphalt in the mixing zone, means for drawing air axially through the drum in the direction from the drying zone to the mixing zone, means for drawing air and suspended particles produced in the drying zone out of the drum from the third zone, and for at least temporarily isolating the suspended particles and air drawn out of the third zone from the asphalt and aggregate in the mixing zone.
Dependencies are inferred from the claim text.