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US 4,626,199 AGranted
Submerged combustion calcination
AssigneeUnited States Gypsum Company
InventorLarbi Bounini
Life of this patent
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Abstract
Gypsum is calcined by contacting it with the hot gases spewing out of a combustion tube submerged in the mass of gypsum. The formation of dead-burned anhydrite is reduced by surrounding the combustion tube with a second tube called a draft tube. Gypsum passing through the annulus between the tubes is heated by the hot gases and is ejected from the annulus to prevent repeated excursions into the hot gas zone at the muzzle of the combustion tube.
Claims8
A calcination apparatus comprising:
- a kettle having a top wall, a sidewall, a bottom wall, a duct extending through the top wall for the introduction of uncalcined material into the kettle, an exhaust vent, and a port for the discharge of calcined material;
- a burner;
- a first tube extending through the top wall into the kettle, said tube communicating with the burner and having an outlet for injecting hot combustion gases from the burner into the material to be calcined;
- a second tube surrounding the first tube and extending beyond the outlet of the first tube, the second tube having an inlet for the material to be calcined and an outlet which is co-axial with the first tube;
- said first and second tubes defining a passageway between them which empties into the second tube.
2 more elements
Dependencies are inferred from the claim text.