Method and apparatus for conveying solids using a high velocity vacuum

A method of conveying solid materials from an excavation site comprising:

• providing a hollow bored tube means having an inlet end and a discharge end and including an injector section therebetween having nozzle means of a converging/diverging type associated with said injector section;
• providing a reservoir of a gas at a pressure of at least 1.9 times greater than an ambient pressure adjacent an exit end of said nozzle means;
• transmitting said gas from said reservoir to said nozzle means to produce a gas stream exiting said nozzle means having a velocity within a supersonic regime;
• directing said supersonic gas stream within the hollow bore of said tube means toward the discharge end thereof, whereby a vacuum is created at the inlet end thereof;
• and
• sucking said solid materials into the inlet end of said tube means by said vacuum and conveying said solid materials entrained within said gas stream through said tube means for discharge at the discharge end thereof.

An apparatus for conveying solid materials from an excavation site and the like, comprising:

• a hollow bored tube member having a longitudinal axis extending therethrough;
• said tube member having an inlet end and a discharge end and including an injector section positioned therebetween;
• nozzle means of the converging/diverging type positioned within said injector section directed toward the discharge end of tube tube member, said nozzle means adapted to communicate with a reservoir containing a pressurized gas whereby said nozzle means is adapted to produce a stream of high velocity gas toward the discharge end of the tube member to create a high vacuum at the inlet end whereby loose solids are drawn into the inlet end and conveyed through said tube member to exit at the discharge end thereof, and wherein the nozzle means comprises three spaced-apart converging/diverging nozzles positioned within said injector section, each of said nozzles having a throat section and an outlet section wherein each of said sections defined a respective cross-section area and wherein the ratio of said outlet section area to said throat section area is greater than 1.0, said injector section also having three off-set segments formed therein at spaced-apart intervals around said tube bore for receiving each of said nozzles therein, said segments having an inner wall portion which is disposed at an angular relationship relative to the sidewall of the bore, whereby said nozzles are recessed inwardly from the sidewall of the bore, wherein each of the nozzles have a longitudinal axis which is inclined relative to the longitudinal axis of the bore of the tube member at an angle of between about 10.degree. to about 15.degree., and wherein each of the inner wall portions of the off-set segments intersect with the sidewall of the bore at an angle of between about 5.degree. to about 71/2.degree. to create at least one Prantdl-Meyer expansion fan per off-set segment.

An apparatus for conveying solid materials from an excavation site and the like, comprising:

• a hollow bored tube member having a longitudinal axis extending therethough;
• said tube member having an inlet end and a discharge end and including an injector section positioned therebetween;
• nozzle means of the converging/diverging type positioned within said injector section directed toward the discharge end of the tube member, said nozzle means adapted to communicate with a reservoir containing a pressurized gas whereby said nozzle means is adapted to produce a stream of high velocity gas toward the discharge end of the tube member to create a high vacuum at the inlet end whereby loose solids are drawn into the inlet end and conveyed through said tube member to exit at the discharge end thereof, and wherein the tube member includes a hollow bored mixing tube section located between the injector section and the discharge end thereof, said mixing tube section having a length of between 6 to about 10 times the bore diameter thereof;
• said tube member further including diffuser means positioned at the discharge end thereof adapted to decelerate the high velocity gas stream prior to exiting said apparatus;
• said diffuser means comprising a flared tubular section having a first end having an inside diameter substantially equal to the bore diameter of the mixing tube section and a diverging transitional portion terminating in a second end having a diameter greater than that of said first end;
• and
• a pleated fabric bag element having an open bottom portion attached to the diffuser means adapted to discharge said decelerated solids through said open bottom portion.