Abstract: A closed loop system which includes (1) a drum mixer, (2) a heat source separate from the drum mixer for producing a heated gas, (3) intake and exhaust ducts which channel, respectively, the gas produced by the heat source to the intake end of the drum mixer, and the gas at the discharge end of the drum mixer back to one intake of the heat source, and (4) a fan for maintaining the flow of gas in the system. The gas produced by the heat source is between 700.degree. F. and 2000.degree. F. when it enters the drum mixer at its intake end from the intake duct. Graded aggregates and a bituminous binder are fed into the drum mixer at its intake end. The graded aggregates are mixed with the bituminous binder, in the presence of the heated gas, by rotational action of the drum mixer. The resulting bituminous paving mixture is discharged at the discharge end of the drum mixer, along with exhaust gas, a portion of which is channeled back to one intake of the heat source by the exhaust duct.

Abstract: A silo and elevator structure disposed in a folded-up arrangement on a trailer bed. Specific ground supports are first installed between the silo legs and ground level, the supports are specifically designed to carry the silo and also the elevator loads during erection procedures and remain part of the final assembly. In addition, the erected silo, which serves as a crane structure for raising and elevating the elevator, stays mounted, via hinge plate mounting brackets, to the trailer structure. Removal of the mounting connection of the hinge plate mounting brackets from the erected silo is the last step of the installation procedure prior to the removal of the trailer from the silo and elevator assembly.

Abstract: An improvement in drum mixer asphalt plants comprising a combustion chamber which substantially completely surrounds an open flame projecting into the inlet end of the drum mixer and prevents the temperature at any point within the drum from reaching the level where it will burn asphaltic materials to produce pollutants which would otherwise be discharged into the atmosphere. At the same time, the combustion chamber will produce heated gases flowing into the drum at a sufficiently high and uniform temperature to melt the asphalt and permit entry of the asphalt and aggregate, including recycled asphalt paving materials, close to the combustion chamber.

Abstract: An improved rotating drum dryer and/or mixer for drying or mixing materials on a continuous basis is disclosed. The dryer and/or mixer includes a rotatable drum having an inlet end for receiving materials and a forced air burner for directing a stream of heated gases axially through the drum. A heat dispersing means such as an array of spaced deflecting bars is disposed downstream from the source of heated gases. The dispersing means provides the interior of the drum with a more uniform radial temperature distribution and minimizes the central high temperature zone normally associated with such drum dryers and/or mixers. Minimization of the central high temperature zone results in lowered production of smoke and other noxious emissions by an operating dryer or mixer.