A conveyor for pulverized material comprising the combination of: a conduit; a screw rotatably mounted within the conduit having a material inlet end and a material discharge end, wherein a pitch of the screw decreases from the material inlet end to the material discharge end thereby compacting the material as it is advanced by the screw to the material discharge end; a motor for rotating the screw, wherein the rotation of the screw results in a formation of a material seal by the compacted material in a portion of the screw; a hopper for supplying material to the screw at the material inlet end; and a compressor for admitting a gas under pressure to the compacted material at the material discharge end to render it fluent whereby the material will be conveyed through the conduit connected to the material discharge end of the screw by the pressure thus applied, wherein the material seal formed by the compacted material prevents the gas from traveling from the material discharge end to the material inlet end; wherein in the material seal forming portion of the screw there are material pockets formed between adjacent screw flights, wherein the decrease in the pitch of the screw from the material inlet end to the material discharge end results in the material pocket closest to the material inlet having the maximum volume of any material pocket and the material pockets having the minimum volume being in the material seal forming portion of the screw nearest the material discharge end, and wherein there are at least two of such minimum volume pockets located in the material seal forming portion of the screw nearest the material discharge end, with each pocket having a volume of about 50% to about 85% of the volume of the maximum size pocket; characterized in that, the conveyor comprises: an exit valve in a form of a dual flapper configured at the material discharge end, wherein the material exits both sides of the screw into an air stream running underneath the screw; and a pipe provided at the material discharge end, wherein the pipe branches into at least two branches, wherein each of the branches is at an angle perpendicular to the screw centerline. a conduit; a screw rotatably mounted within the conduit having a material inlet end and a material discharge end, wherein a pitch of the screw decreases from the material inlet end to the material discharge end thereby compacting the material as it is advanced by the screw to the material discharge end; a motor for rotating the screw, wherein the rotation of the screw results in a formation of a material seal by the compacted material in a portion of the screw; a hopper for supplying material to the screw at the material inlet end; and a compressor for admitting a gas under pressure to the compacted material at the material discharge end to render it fluent whereby the material will be conveyed through the conduit connected to the material discharge end of the screw by the pressure thus applied, wherein the material seal formed by the compacted material prevents the gas from traveling from the material discharge end to the material inlet end; wherein in the material seal forming portion of the screw there are material pockets formed between adjacent screw flights, wherein the decrease in the pitch of the screw from the material inlet end to the material discharge end results in the material pocket closest to the material inlet having the maximum volume of any material pocket and the material pockets having the minimum volume being in the material seal forming portion of the screw nearest the material discharge end, and wherein there are at least two of such minimum volume pockets located in the material seal forming portion of the screw nearest the material discharge end, with each pocket having a volume of about 50% to about 85% of the volume of the maximum size pocket; characterized in that, the conveyor comprises: an exit valve in a form of a dual flapper configured at the material discharge end, wherein the material exits both sides of the screw into an air stream running underneath the screw; and a pipe provided at the material discharge end, wherein the pipe branches into at least two branches, wherein each of the branches is at an angle perpendicular to the screw centerline. an exit valve in a form of a dual flapper configured at the material discharge end, wherein the material exits both sides of the screw into an air stream running underneath the screw; and a pipe provided at the material discharge end, wherein the pipe branches into at least two branches, wherein each of the branches is at an angle perpendicular to the screw centerline.