| 摘要 |
A drum mixer having a combined heating-mixing zone which receives aggregate from both ends. The drum mixer includes a rotatable drum having an inlet end and a discharge end. Within the drum, a drying zone extends from the inlet end to a combustion zone and a mixing zone extends from the combustion zone to the discharge end. A cylindrical, tubular combustion housing is mounted in the combustion zone to define the heating-mixing zone between the drum and the combustion housing. The inner periphery of the combustion housing defines a combustion chamber into which the flame of a burner assembly is directed. The heating-mixing zone communicates with the drying zone, the combustion chamber, and the mixing zone. Aggregate is introduced into the drying zone and is urged toward the combustion zone as the drum is rotated. Upon reaching the combustion zone, a first portion of the aggregate enters the heating-mixing zone without entering the combustion chamber and a second portion of the aggregate travels through the combustion chamber before entering the heating-mixing zone. A recycle feed chute is provided to introduce recycle material into the heating-mixing zone. The aggregate-recycle mixture is then urged from the heating-mixing zone into the mixing zone, where liquid asphalt is added to produce an asphaltic composition.
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