Dry flow pumps

Claim 1

A dry flow pump comprising: a. a hopper housing adapted to receive material to be pumped; b. a pump barrel exiting from said hopper housing and terminating in a forwardly and downwardly inclined discharge extremity; c. a rotatable, power-driven screw conveyor passing through said hopper housing and into said pump barrel to force material from the former through the latter; d. an air chamber circumferentially surrounding said pump barrel in radial-spaced-relation to the latter, the forward extremity of said air chamber being open to discharge air circumferentially about the discharge extremity of said pump barrel; e. an air manifold substantially surrounding said air chamber and provided with means for receiving compressd air from an external source; f. an annular plurality of circumferentially spaced ports communicating from said air manifold to said air chamber; g. a shaft extension projecting rearwardly from said screw conveyor; h. a cylindrical bearing housing projecting rearwardly from said hopper housing concentrically about said shaft extension; i. a shaft bearing positioned at the rear extremity of said bearing housing and rotatably supporting said screw conveyor; j. a spool-shaped cylindrical bearing block having forward and rear flanges positioned in said bearing block about said shaft, the intervening circumferential space between said flanges forming a cylindrical compressed air chamber about said block; k. means for sealing the rear extremity of said bearing block to said shaft and means for sealing the forward flange to said bearing housing; l. means for conducting compressed air to said chamber; m. a plurality of air ports positioned at the rear of said air chamber and communicating with said shaft; and n. a helical air channel formed in the cylindrical surface of said channel pitched to convey the air received from said ports spirally forward to the hopper housing so as to detract the air away from said shaft bearing to reduce the possibility of bearing damage.