Patent ID: 7285208
Filing Date: 2007-10-23
Classification: B01F,C02F,Y02A,Y02W

Abstract:
1. A circulation system for a body of water having a surface and a bottom and further having an upper zone extending downwardly from the surface and a lower zone extending upwardly from the bottom toward the upper zone wherein a circulating flow is established and substantially limited to the upper zone leaving the lower zone substantially isolated therefrom while bringing up a relatively small volume of the contents of the lower zone into the upper zone for circulation therein with the existing contents of the upper zone, said system including: a flotation platform, a dish substantially supported adjacent the surface of the body of water, an impeller, a housing adjacent said impeller, a draft tube, and a draft tube supporting arrangement, said supporting arrangement including a plate member extending substantially horizontally about and outwardly of a substantially vertical axis and being vertically spaced from and below said impeller and said housing, said plate member and said housing creating an inlet opening therebetween to said impeller, said inlet opening extending substantially about said vertical axis, said draft tube having a main body, an inlet portion, and an outlet portion, said main body extending downwardly from said plate member to position the inlet portion thereof adjacent the lower zone of said body of water, said plate member having an opening therethrough and said outlet portion of said draft tube extending through said opening up to a position above said plate member adjacent said impeller wherein said impeller draws a first volume of water substantially horizontally above said plate member with a portion thereof passing through the inlet opening between the plate member and the housing to the impeller and toward the surface of the body of water and the remaining portion of said first volume being induced by the movement of the first portion to flow toward the surface of the body of water about the housing to thereby establish a circulating flow defining said upper zone, said impeller further drawing a second volume of water up from the lower zone through said draft tube and into said upper zone, said second volume being a relatively small fraction of the first volume.