Compacting screw feeder

Claim 1

Apparatus for removing air from particulate solids stored in a source chamber, comprising in combination: a screw feeder extending in a horizontal direction and including a number of sections arrayed in succession along its length so as to subject the particulate solids to a succession of operations, said sections including, a feeding section extending into the source chamber for drawing the particulate solids from the source chamber into the apparatus; a feed seal section, adjacent said feeding section and having the same pitch as the adjacent portion of said feeding section; a conveying section adjacent said feed seal section and having a greater pitch to provide greater solids-moving capacity than said feed seal section; a recirculation section adjacent said conveying section and having substantially the same pitch as said conveying section; a high pressure section having substantially the same pitch as said recirculation section; a recirculation chamber through which said screw feeder extends, said recirculation chamber including, a feeder seal shroud closely surrounding said feed seal section of said screw feeder; a high pressure shroud closely surrounding said high pressure section of said screw feeder and having an output end; said recirculation chamber further enclosing said conveying section and said recirculation section, to confine particulate solids blown out of said high pressure section of said screw feeder as the particulate solids are compressed thereby; and, a hingedly mounted preloaded cover in yieldable sealing engagement with the output end of said high pressure shroud to permit the particulate solids pressurized by said high pressure section to emerge under pressure from said high pressure shroud.