US 4,226,668 AGranted

Spray drying apparatus utilizing pulse jet engines

AssigneeSonic Dehydrators, Inc.

InventorFrederick A. Ferguson

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Abstract

Spray drying apparatus is disclosed wherein circumferentially spaced apart exhaust pipes of three L-shaped pulse jet engines extend upwardly into the floor of a cylindrical drying chamber. The engines extend radially outward beneath the floor of the drying chamber, with the engine inlet openings being supported in spaced apart juxtaposition with air augmentation ducts which extend upwardly and tangentially into the drying chamber at equally spaced apart positions near the drying chamber floor. Moisture laden material, such as a slurry tht contains the material to be dried is introduced into the upwardly directed exhaust stream of each engine by means of feedpipes which pass coaxially along the interior of each engine exhaust pipe and an injection nozzle that is affixed to the terminus of each feedpipe at a predetermined distance below the engine exhaust opening. The hot flowing exhaust gases and broad band acoustic energy supplied by the engines atomizes or divides the injected material and causes a substantial reduction in moisture content as the injected material passes to the drying chamber. Moisture removal continues as the material is borne upwardly through and about the drying chamber by the engine exhaust and airflow introduced by the augmentation ducts. The portion of the material reaching the top of the drying chamber is removed through a product outlet opening and the portion falling to the drying chamber floor is swept circumferentially around the chamber floor by the tangentially directed streams of air supplied by the air augmentation ducts. A conventional screw type conveyor that extends across a portion of the chamber floor receives and removes this portion of the material.

Claims12

Dependent claims

Spray drying apparatus comprising:

a drying chamber having a first boundary surface and a boundary wall extending outwardly from the periphery of said first boundary surface;
at least one pulse jet engine having an exhaust pipe, an air intake section and a combustion chamber positioned between said exhaust pipe and said air intake section, said exhaust pipe of each of said pulse jet engines extending to said first boundary surface of said drying chamber for exhausting high temperature gaseous flow inwardly into said drying chamber;
at least one air augmentation duct, each augmentation duct having an entrance opening positioned in spaced apart juxtaposition with the opening in the air intake section of an associated pulse jet engine, each air augmentation duct being configured to enter said drying chamber at a predetermined position in said boundary wall and proximate to said periphery of said first boundary surface, each air augmentation duct being configured and arranged for receiving high temperature gaseous flow emerging from said air inlet section of said associated pulse jet engine and ambient air entrained therewith, each air augmentation duct being further configured and arranged to direct said received gaseous flow and ambient air into said drying chamber to establish substantially circumferential flow along at least the outer regions of said first boundary surface, said circumferential flow established by air augmentation ducts interacting with the upwardly directed gaseous flow supplied by said pulse jet engine exhaust pipes to create inwardly and circumferentially directed flow in the direction away from said first boundary surface of said drying chamber;
and
supply means for introducing the material to be dried into said exhaust pipe of each of said pulse jet engines, said high temperature gaseous flow within each of said exhaust pipes and attendant high level acoustic energy supplied by said pulse jet engines atomizing said material and effecting substantial moisture removal as said material passes through said exhaust pipe and into said drying chamber, said inwardly and circumferentially directed gaseous flow established by said air augmentation ducts and said inwardly directed flow of pulse jet engine exhaust carrying said atomized material into and about said drying chamber for additional moisture removal.

2 more elements

An improved drying system of the type employing a plurality of pulse jet engines each having an exhaust pipe and air inlet section extending outwardly from the oppositely disposed ends of a combustion chamber wherein the material to be dried is injected into the exhaust pipe of one more of said pulse jet engines and borne upwardly through openings in the floor of a drying chamber by the pulsating gaseous exhaust stream of each pulse jet engine that receives said material to be dried, said improved drying system characterized in that the material to be dried is injected into said exhaust pipe of every pulse jet engine utilized in said drying system with said exhaust pipe of each said pulse jet engines being angularly disposed relative to the air inlet section thereof, each of said pulse jet engines being mounted and arranged with said air inlet section extending radially outward beneath the floor region of said drying chamber;

said improved drying system further comprising a plurality of air augmentation ducts in one-to-one correspondence with said plurality of pulse jet engines, each of said air augmentation ducts having an entrance opening radially spaced apart from the inlet opening in the air inlet section of the corresponding pulse jet engine, each of said air augmentation ducts being contoured and arranged for directing a portion of the combustion products effluxed through said air inlet opening of said corresponding pulse jet engine and ambient air entrained therewith outwardly and upwardly for discharge into said drying chamber at spaced apart positions along said floor, each of said air augmentation ducts being further contoured and arranged to discharge said portion of said combustion products and said entrained ambient air along a path that is substantially tangential to the boundary wall of said drying chamber.

Dependencies are inferred from the claim text.