Abstract: A fluid bed dryer includes a tank with an upright wall, a top, and a floor which rotates under a plurality of blades adjacent the floor and fixed to an inner annular baffle. A gas manifold is defined between the tank wall and the baffle, and opens under the baffle into a drying space in the tank.A pulse jet engine pumps pulsating hot gas and sonic waves to the gas manifold to fluidize a bed of moist particles which are introduced into the drying space above the blades. There is a time average uniform exposure of the bed to the fluidizing gas effected by continuously changing the exposure of the particles to the gas. Pulsating hot gas and sonic energy waves flow from the periphery of the tank toward the center of the dryer. The pulse jet engine also supplies an auxiliary gas inlet at the side of the tank to maintain a swirl of gas above the fluidized bed. An adjustable bypass diverts the flow of gas from the auxiliary inlet to the gas manifold for adjusting the strength of the gas swirl.
Abstract: A perforated drum serves as a drying chamber into which moist particles are loaded. The drum is rotated about a horizontal axis to tumble the particles. Sonic energy and hot pulsating gas from a pulse jet engine are supplied to a plenum opening into the drum.The gas flows through the drum transversely to the axis and contacts the tumbling particles to dry them. A shroud encloses the drum. Moisture-laden gas exhausted from the drum is collected in the shroud and recycled to the pulse jet engine. Sonic energy escaping from the drum is reflected by the shroud back into the drum. The particles are continually exposed to pulsating hot gas and reflected sonic energy. Dried product is withdrawn from the dryer.