Process and means for the heat treatment of powdery or granulate material
First Claim
1. In a process for heat treating agitated powder or granulate material contained in a closed drum wherein hot gas is driven through the material, the improvement which comprises the gas comprising a treatment agent and a carrier gas at a temperature sufficient that the treatment agent is present in the vapor state and is drawn through the agitated material, said material being at a temperature below the boiling temperature of the treatment agent and at nearly pressure, and after the desired reaction time, the treatment agent condensed on the material is evaporated and drawn out of the drum by the application of a vacuum at or below the pressure corresponding the boiling point of the treatment agent.
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Accused Products
Abstract
Solid, loose particulate materials are treated with vaporizable agent in a process chamber. The materials are combined with a mixture of hot gas and vapor in order to condense finely subdivided amounts of the treatment agent on the material. After a suitable time of reaction, the condensed material is partially removed from the treated material so that the pressure in the process chamber is reduced at least to the point at which the treatment agent partially evaporates, whereupon the portion which has revaporized is extracted from the process chamber. This cycle of introduction and removal of the treating agent is preferably repeated in a program-controlled operation until the desired result is achieved and a product which is suitably agglomerated is obtained. In the present process, particulate material in powder or granule form is agitated and heat-treated in a closed drum, by stirring agents and surface treated by a hot gas flow forced over or through the charge of the material and then extracted intermittently by a vacuum pump. The air is heated and vaporized so that the vapor does not condense on the charge material.
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Citations
18 Claims
- 1. In a process for heat treating agitated powder or granulate material contained in a closed drum wherein hot gas is driven through the material, the improvement which comprises the gas comprising a treatment agent and a carrier gas at a temperature sufficient that the treatment agent is present in the vapor state and is drawn through the agitated material, said material being at a temperature below the boiling temperature of the treatment agent and at nearly pressure, and after the desired reaction time, the treatment agent condensed on the material is evaporated and drawn out of the drum by the application of a vacuum at or below the pressure corresponding the boiling point of the treatment agent.
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7. A process for the treatment of material in a closed drum, wherein intermittently, until a predetermine result is achieved
(i) a hot gas flow is passed over or through a charge of solid, granulate material, and (ii) wherein hot air in the drum is extracted by vacuum, characterized in that the hot gas flow before entering the drum is under pressure and contains vaporous treatment agent, and wherein the drum wall is heated and wherein the hot gas supply is interrupted during at least a part of the extraction phase.
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16. A process for heat treating an agitated powder or granulate material comprising passing a hot gas having entrained therein a vaporized treatment agent, the boiling point of the treatment agent being between 0°
- and 200°
C. and the temperature of the hot gas being at least 10°
greater than said boiling point and the concentration of said agent being from 0.1 to 55 volume %, through a vacuum vessel containing said powder or granulate at a temperature below the boiling point of said treatment agent, with the prevailing vacuum and temperature conditions being such that at least a part of the treatment agent condenses, thereafter adjusting said prevailing conditions such that at least a part of the condensed treatment agent vaporizes, and removing the vessel vaporized treatment agent from the vessel. - View Dependent Claims (17, 18)
- and 200°
Specification