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Abstract

A method and apparatus for devulcanizing cured or cross-linked elastomers. The method includes subdividing elastomeric raw material into small particle form, confining the particles of elastomer under high force, as in a screw extruder or the like and, as the particles remain confined, imparting ultrasonic energy to the mass to effect devulcanization. Energy is fed to the confined particles transversely of the axis along which they are advancing, and energy from a source is reflected off a portion of the apparatus and back into the treatment zone so as to achieve maximum energy utilization. In particular instances, reflection of energy is achieved by providing opposed, powered ultrasonic horns that resonate in phase with each other. In another embodiment, oppositely directed, resonantly tuned horns are used, with less than all such horns being powered and the remainder being passive or unpowered reflecting horns who resonant frequency is tuned to that of the powered horn. In one apparatus, the pairs of horns resonate in phase by reason of delay lines interposed between the two power sources. In the other form, the mass of the passive horn is balanced with that of the active horn to achieve in-phase tuning that maximizes reflection of energy.

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First Claim