Method of improving flow of particulate material

Claim 1

A method of improving flow of dry, bulk solids in a hopper having a sloping side wall converging downwardly toward a discharge opening adjacent the bottom of the hopper, said material normally cooperating with said sloping side wall to restrict flow toward said discharge opening whereby material within the hopper forms arches abutting said sloping side wall of said hopper, said method comprising: a. positioning a shroud in a hopper at a height relative to a sloping side wall of the hopper selected to provide a predetermined space between an outer edge of said shroud and said side wall and at a predetermined spacing of said shroud above a discharge opening adjacent the bottom of the hopper and providing substantially unrestricted flow below the shroud and through the discharge opening whereby the shroud does not restrict flow through the discharge opening; and b. directing a stream of gas upwardly from said shroud and into material above said shroud and through the material in said hopper with sufficient velocity to maintain a column of the material in a fluidized state from said shroud upwardly through the portion of material normally cooperating with said sloping side wall to restrict flow anD including extending the stream of gas through material forming arches abutting said sloping hopper side wall thereby aerating the material throughout a zone between said column and said sloping side wall whereby transverse and circumferential bridging is eliminated and the material flows downwardly without restriction and through the space between said shroud and said sloping side wall and into the space below said shroud and above the discharge opening.

Claim 2

A method of improving flow of dry, bulk solids in a hopper having a sloping side wall converging downwardly toward a discharge opening adjacent the bottom of the hopper, said material normally cooperating with said sloping side wall to restrict flow toward said discharge opening whereby material within the hopper forms arches abutting said sloping side wall of said hopper, said method comprising: a. positioning a shroud in a hopper at a height relative to a sloping side wall of the hopper selected to provide a predetermined space between an outer edge of said shroud and said side wall and at a predetermined spacing of said shroud above a discharge opening adjacent the bottom of the hopper and providing substantially unrestricted flow below the shroud and through the discharge opening whereby the shroud does not restrict flow through the discharge opening; and b. directing a stream of gas upwardly from said shroud and into material above said shroud and through the material in said hopper with sufficient velocity to maintain a column of the material in a fluidized state from said shroud upwardly through the portion of material normally cooperating with said sloping side wall to restrict flow anD including extending the stream of gas through material forming arches abutting said sloping hopper side wall thereby aerating the material throughout a zone between said column and said sloping side wall whereby transverse and circumferential bridging is eliminated and the material flows downwardly without restriction and through the space between said shroud and said sloping side wall and into the space below said shroud and above the discharge opening.

Claim 6

A method of improving flow of dry, bulk solids and avoiding bridging, slugging, and segregation of particulate material while the particulate material is being discharged from a hopper having opposite sloping wall portions converging toward a discharge opening at the bottom of the hopper, said material normally cooperating with said sloping wall portions to restrict flow toward the discharge opening and forming arches abutting said sloping side wall portions of said hopper, said method comprising: a. positioning a shroud in a hopper having opposite sloping wall portions converging toward a discharge opening at the bottom of the hopper and at a selected location spaced above a discharge opening adjacent the bottom of the hopper and providing substantially unrestricted flow below the shroud and through the discharge opening; and b. directing a stream of gas upwardly from the selected location and in a column thereby fluidizing a portion of particulate material in the hopper and breaking transverse arches of the material extending between opposite sloping wall portions of the hopper and aerating the material between said fluidized column and the opposite sloping wall portions of said hopper and thereby passing said material in an aerated state through a space between the lower end of said fluidized column and said hopper walls and into a space under the lower end of said fluidized column and subsequently through the discharge opening whereby the material is discharged from said hopper without forming rat holes, arches, and circumferential bridging and the material is mixed as it passes through the converging portion of said hopper.

Claim 7

A method of improving flow of dry, bulk solids and avoiding bridging, slugging, and segregation of particulate material while the particulate material is being discharged from a hopper having opposite sloping wall portions converging toward a discharge opening at the bottom of the hopper, said material normally cooperating with said sloping wall portions to restrict flow toward the discharge opening and forming arches abutting said sloping side wall portions of said hopper, said method comprising: a. positioning a shroud in a hopper having opposite sloping wall portions converging toward a discharge opening at the bottom of the hopper and at a selected location spaced above a discharge opening adjacent the bottom of the hopper and providing substantially unrestricted flow below the shroud and through the discharge opening; and b. directing a stream of gas upwardly from the selected location and in a column thereby fluidizing a portion of particulate material in the hopper and breaking transverse arches of the material extending between opposite sloping wall portions of the hopper and aerating the material between said fluidized column and the opposite sloping wall portions of said hopper and thereby passing said material in an aerated state through a space between the lower end of said fluidized column and said hopper walls and into a space under the lower end of said fluidized column and subsequently through the discharge opening whereby the material is discharged from said hopper without forming rat holes, arches, and circumferential bridging and the material is mixed as it passes through the converging portion of said hopper.

Claim 10

A method of discharging particulate material from a hopper having a substantially frusto-conical side wall converging toward a discharge opening at the bottom thereof, said side wall having a slope sufficiently great to cause bridging within the material during gravity flow through the discharge opening, said method comprising: a. introducing particulate material into a hopper having a substantially frusto-conical side wall converging downwardly toward a discharge opening at the bottom thereof and having a slope sufficiently great to cause bridging within the material during gravity flow through the discharge opening; b. directing a stream of gas upwardly from a selected location above the discharge opening in a column extending upwardly therefrom thereby fluidizing a central column of the material, said fluidized column having the lower end thereof spaced above said discharge opening and extending across the width of said hopper a distance between one-half and three-quarters of the width of said hopper as measured at a horizontal cross section passing through the lower end of the fluidized column whereby the fluidized column is of a size to break up material arches abutting said sloping wall portions of the hopper; c. confining a space above the material within said hopper whereby the gas flows through the material thereby aerating the material in said hopper throughout a zone between said fluidized column and said sloping side wall whereby transverse and circumferential bridging is eliminated and the material flows downwardly without restriction and through a space between the lower end of said fluidized column and said sloping side wall and into a space below said lower end of said fluidized column and above the discharge opening; and d. withdrawing material through said discharge opening from the zone between the lower end of said fluidized column and the bottom of said side wall.

Claim 11

A method of discharging particulate material from a hopper having a substantially frusto-conical side wall converging toward a discharge opening at the bottom thereof, said side wall having a slope sufficiently great to cause bridging within the material during gravity flow through the discharge opening, said method comprising: a. introducing particulate material into a hopper having a substantially frusto-conical side wall converging downwardly toward a discharge opening at the bottom thereof and having a slope sufficiently great to cause bridging within the material during gravity flow through the discharge opening; b. directing a stream of gas upwardly from a selected location above the discharge opening in a column extending upwardly therefrom thereby fluidizing a central column of the material, said fluidized column having the lower end thereof spaced above said discharge opening and extending across the width of said hopper a distance between one-half and three-quarters of the width of said hopper as measured at a horizontal cross section passing through the lower end of the fluidized column whereby the fluidized column is of a size to break up material arches abutting said sloping wall portions of the hopper; c. confining a space above the material within said hopper whereby the gas flows through the material thereby aerating the material in said hopper throughout a zone between said fluidized column and said sloping side wall whereby transverse and circumferential bridging is eliminated and the material flows downwardly without restriction and through a space between the lower end of said fluidized column and said sloping side wall and into a space below said lower end of said fluidized column and above the discharge opening; and d. withdrawing material through said discharge opening from the zone between the lower end of said fluidized column and the bottom of said side wall.