초록 ▼

A drum mixer is provided with a rotatable cylinder in which aggregates, reclaimed asphalt pavement and liquid asphalt are mixed to produce an asphaltic composition. The drum cylinder includes a first region, in which virgin aggregate is heated and dried by heat radiation and the stream of hot gases

A drum mixer is provided with a rotatable cylinder in which aggregates, reclaimed asphalt pavement and liquid asphalt are mixed to produce an asphaltic composition. The drum cylinder includes a first region, in which virgin aggregate is heated and dried by heat radiation and the stream of hot gases produced by a burner flame flowing in countercurrent flow to the aggregate itself to establish a highly beneficial heat transfer relationship. A second region doubles as combustion and mixing zones. In the mixing zone the reclaimed asphalt pavement and liquid asphalt is added and mixed with the aggregates. The combustion zone is formed along the center of the mixing zone by an elongated combustion assembly disposed along the central axis thereof. The combustion assembly and chamber extend from the discharge end of the drum through the mixing zone to the heating and drying zone to segregate the hot gases from the asphalt, thereby preventing degradation of the final product. The hot gas stream is withdrawn from the drum cylinder at the upstream or inlet end thereof and delivered by ductwork to air pollution control equipment. Accordingly, while the liquid asphalt, recycle material and virgin aggregate are mixed in the mixing zone in an annular region between the drum cylinder and the combustion assembly, contact with the burner flame or with the hot gas stream is eliminated.

대표청구항 ▼

A drum mixer for producing an asphaltic composition from asphalt and aggregates, said mixer comprising: a rotatable cylinder having inlet and discharge ends with an internal passageway communicating therebetween, said passageway being separated into a first region including a heating/drying zone and

A drum mixer for producing an asphaltic composition from asphalt and aggregates, said mixer comprising: a rotatable cylinder having inlet and discharge ends with an internal passageway communicating therebetween, said passageway being separated into a first region including a heating/drying zone and into a second region including a mixing zone surrounding a multi-stage combustion zone, said mixing and combustion zones having equal lengths and extending throughout said second region; drive means to rotate said cylinder about a central longitudinal axis thereof; aggregate feed means adjacent said inlet end of said cylinder for delivering aggregate material to said heating/drying chamber; liquid asphalt feed means, positioned intermediate said inlet and discharge ends of said cylinder, for delivering liquid asphalt to said mixing zone; flighting means, in said mixing zone, for mixing said liquid asphalt and aggregate to form an asphaltic composition product; and a combustion assembly penetrating said discharge end of said cylinder and extending into said second region to form said multistage combustion zone, said combustion assembly including a burner head, positioned at said discharge end, to deliver a hot gas stream to said heating/drying chamber to heat and dry said aggregate, said combustion assembly isolating said hot gas stream from said mixing chamber; and discharge means for directing said asphaltic composition product from said mixing zone.