초록 ▼

A drum mixer is disclosed which is useful in the continuous production of asphalt paving composition. The mixer includes a hollow drum which is mounted for rotation about an inclined axis, and the aggregate is introduced into the upper end of the drum so that the drum rotates, the aggregate cascades

A drum mixer is disclosed which is useful in the continuous production of asphalt paving composition. The mixer includes a hollow drum which is mounted for rotation about an inclined axis, and the aggregate is introduced into the upper end of the drum so that the drum rotates, the aggregate cascades through the interior of the drum and moves toward a discharge outlet at the lower end of the drum. A burner is mounted adjacent one end of the drum so that a heated gas passes through cascading aggregate. To permit the temperature of the exhaust gas to be maintained within acceptable limits so as to avoid detrimental effects to a downstream filtering baghouse, there is provided a gas flow bypass tube which is mounted coaxially within the drum. The tube may be selectively opened and closed, and upon opening the bypass tube, a portion of the heated gas is able to pass freely through a portion of the length of the drum and to the exhaust duct, without passing through the cascading aggregate. Thus the temperature of the exhaust gas rises. Upon the bypass tube being closed, all of the heated gas flows through the cascading aggregate, and the temperature of the exhaust gas is lowered.

대표청구항 ▼

A drum mixer adapted for heating and drying stone aggregate in the continuous production of asphalt paving composition or the like, and comprising an elongate hollow drum defining a central axis, means mounting said drum for rotation about said central axis and with said central axis being inclined

A drum mixer adapted for heating and drying stone aggregate in the continuous production of asphalt paving composition or the like, and comprising an elongate hollow drum defining a central axis, means mounting said drum for rotation about said central axis and with said central axis being inclined with respect to the horizontal so as to define an upper end and a lower end of said drum, aggregate inlet means positioned adjacent said upper end of said drum for introducing aggregate into the interior of said drum, aggregate outlet means position adjacent said lower end of said drum for withdrawing the aggregate from the interior of said drum, means for rotating said drum about said central axis so as to cause the aggregate which is introduced at said inlet means to cascade through the interior of said drum and move to said outlet means, heating means positioned adjacent one of said ends of said drum for introducing heated gas into the interior of said drum, exhaust duct means positioned adjacent the other of said ends of said drum for exhausting the heated gas therefrom and so that the heated gas flows through said drum and through the cascading aggregate, and gas flow bypass means positioned within the interior of said drum for selectively permitting some of the heated gas flowing through said drum to pass freely through a portion of the length of said drum without passing through the cascading aggregate, said gas flow bypass means comprising a tube coaxially mounted within said drum to extend in the direction of said central axis, valve means for selectively controlling the flow of the heated gases through said tube and comprising plate means mounted for movement between a closed position closing one end of said tube and an open position withdrawn from said one end of said tube, and drive means for selectively moving said valve means between said open and closed positions.