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US 4,358,206 AGranted
Draft tube apparatus
AssigneeGeneral Signal Corporation
InventorMarlin D. Schutte
Life of this patent
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AssigneeGeneral Signal Corporation
InventorMarlin D. Schutte
Estimating the term…
Improved draft tube mixing apparatus having one or more of the following features: (a) controlled circulation at the inlet of the tube which allows operation at reduced submergence by preventing formation of a vortex; (b) an additional passage for controlled flow into the draft tube along its length to allow operation without the tube being entirely submerged; (c) the recovery of dynamic energy from the flow at the outlet of the tube by wide area diffusion without separation from the walls of the tube in the diffusing region thereof; (d) improved guidance of radially directed to axially directed flow at the inlet of the draft tube for efficient axial pumping by the impeller by maintaining generally uniform axial flow velocity radially of the impeller; and (e) separation of coarse and fine particles in suspension in the tank to allow selective draw-off of the coarse and/or fine particles thereby increasing efficiency of mixing.
Draft Tube apparatus for use in a tank containing liquid to be mixed which comprises a draft tube disposed in said tank, an impeller in said draft tube for providing axial flow of said liquid therein, flow guide means disposed at the inlet region of said draft tube to change the direction of flow in said region from radially to axially directed flow of generally uniform velocity, said guide means comprising an annular open tubular member spaced from the walls of said tank having a first tubular section at one end thereof extending axially into said draft tube at said inlet, and a second section at the opposite end thereof being in its entirety spaced axially outward from the inlet end of said draft tube and extending outwardly from said draft tube inlet and radially away from said draft tube.
Dependencies are inferred from the claim text.