Modular screw conveyor

Claim 2

A screw conveyor composed of a plurality of like modules mated end-to-end, each of said plurality of modules being integrally molded and each of said plurality of modules comprising: a central tube having first and second ends and an opening extending therethrough between said first and second ends, said opening having a non-circular cross section; a helical web disposed around the outer surface of said central tube and integrally formed thereto, said helical web having a predetermined length and first and second ends extending axially outwardly of said first and second ends of said central tube, respectively, by a predetermined length; said first and second ends of said central tube having means for sealingly engaging adjacent ones of said plurality of like modules as mated end-to-end to form said screw conveyor to provide helical screw conveying surfaces disposed around an effectively continuous central tube; said first and second ends of said helical web having means for confronting corresponding means on adjacent ones of said plurality of like modules as mated end-to-end to form said screw conveyor to provide helical screw conveying surfaces disposed around an effectively continuous central tube; a tensile member extending through said openings of said effectively continuous central tube of said plurality of like modules mated end-to-end to form said screw conveyor, said tensile member having a non-circular cross section corresponding to said non-circular cross section of said opening of said central tube; and means for securing ends of said tensile member with respect to end ones of said plurality of like modules to maintain said plurality of like modules mated end-to-end in compressive mated engagement.

Claim 3

The screw conveyor of claim 1 wherein each said sealing engaging means of said first and second ends of said central tube includes an integral portion formed at each of said first and second ends.

Claim 4

The screw conveyor of claim 1 wherein each said confronting means of said first and second ends of said helical web is a surface integrally formed at said first and second ends for confronting corresponding means of said adjacent ones of said plurality of like modules mated end-to-end to form said screw conveyor.

Claim 5

The screw conveyor of claim 3 wherein each said surface on one of said first and second ends of said helical web is oppositely facing with respect to said surface on the other of said first and second ends of said helical web wherein each of said surfaces of said first and second ends of said helical web is mateable with an oppositely facing surface of an adjacent one of said plurality of like modules as mated end-to-end to form said screw conveyor.

Claim 6

The screw conveyor of claim 4 wherein said helical web has a predetermined thickness and said predetermined length of which each of said first and second ends of said helical web extends axially outwardly of said first and second ends of said central tube, respectively, is about one half of said predetermined thickness of said helical web, and further wherein said first and second ends of each said helical web lie in a radial plane.

Claim 7

The screw conveyor of claim 5 wherein said predetermined length of each said helical web is about one percent less than one helical pitch length.

Claim 8

The screw conveyor of claim 1 wherein end portions of each said opening extending through said central tube are tapered, and wherein each said end portion has a cross section corresponding to said non-circular cross section of said opening of said central tube.

Claim 9

A plastic screw conveyor, comprising: a plurality of integrally molded like modules mated end-to-end to form said plastic screw conveyor, each of said integrally molded modules including a central tube having a non-circular aperture extending therethrough and first and second ends, said non-circular aperture having a cross section, a helical web having a length about one percent less than one helical pitch length disposed around the outer surface of said central tube and integrally molded therewith, said helical web having first and second ends extending axially outwardly of said first and second ends of said central tube, respectively, by a predetermined length, each one of said first and second ends of said central tube having means for sealingly engaging adjacent ones of said plurality of integrally molded like modules as mated end-to-end to form said plastic screw conveyor to provide a helical screw conveying surface disposed around an effectively continuous central tube, said first and second ends of said helical web having means for confronting corresponding means on adjacent ones of said plurality of integrally molded like modules as mated end-to-end to form said plastic screw conveyor to provide a helical screw conveying surface disposed around an effectively continuous central tube, said plastic screw conveyor having a length determined by the number of integrally molded like modules mated end-to-end constituting said plurality of integrally molded like modules; a drive shaft extending substantially the length of said screw conveyor through each of said non-circular apertures of said plurality of integrally molded like modules as mated end-to-end to form said plastic screw conveyor, said drive shaft having a non-circular cross-section corresponding to said cross section of said non-circular aperture, said non-circular cross section of said drive shaft cooperating with each of said non-circular apertures of said plurality of integrally molded like modules such that rotation of said drive shaft causes uniform rotation of said plurality of integrally molded like modules; and fastening means located at each end of said shaft to maintain said plurality of integrally molded like modules as mated end-to-end to form said plastic screw conveyor, and to allow limited axial movement of said plurality of integrally molded like modules on said drive shaft resulting from expansion and contraction of said plurality of integrally molded like modules due to changes in temperature.

Claim 10

A plastic screw conveyor, comprising: a plurality of integrally molded like modules mated end-to-end to form said plastic screw conveyor, each of said integrally molded modules including a central tube having a non-circular aperture extending therethrough and first and second ends, said non-circular aperture having a cross section, a helical web having a length about one percent less than one helical pitch length disposed around the outer surface of said central tube and integrally molded therewith, said helical web having first and second ends extending axially outwardly of said first and second ends of said central tube, respectively, by a predetermined length, each one of said first and second ends of said central tube having means for sealingly engaging adjacent ones of said plurality of integrally molded like modules as mated end-to-end to form said plastic screw conveyor to provide a helical screw conveying surface disposed around an effectively continuous central tube, said first and second ends of said helical web having means for confronting corresponding means on adjacent ones of said plurality of integrally molded like modules as mated end-to-end to form said plastic screw conveyor to provide a helical screw conveying surface disposed around an effectively continuous central tube, said plastic screw conveyor having a length determined by the number of integrally molded like modules mated end-to-end constituting said plurality of integrally molded like modules; a drive shaft extending substantially the length of said screw conveyor through each of said non-circular apertures of said plurality of integrally molded like modules as mated end-to-end to form said plastic screw conveyor, said drive shaft having a non-circular cross-section corresponding to said cross section of said non-circular aperture, said non-circular cross section of said drive shaft cooperating with each of said non-circular apertures of said plurality of integrally molded like modules such that rotation of said drive shaft causes uniform rotation of said plurality of integrally molded like modules; and fastening means located at each end of said shaft to maintain said plurality of integrally molded like modules as mated end-to-end to form said plastic screw conveyor, and to allow limited axial movement of said plurality of integrally molded like modules on said drive shaft resulting from expansion and contraction of said plurality of integrally molded like modules due to changes in temperature.

Claim 11

The screw conveyor of claim 8 wherein said sealing engaging means of each one of said first and second ends of said central tube includes an integral portion formed at each one of said first and second ends.

Claim 12

The screw conveyor of claim 8 wherein each of said confronting means of said first and second ends of said helical web is a surface integrally formed at said first and second ends for confronting corresponding means of said adjacent ones of said plurality of integrally molded like modules mated end-to-end to form said screw conveyor and wherein said surface on one of said first and second ends of said helical web is oppositely facing with respect to said surface on the other of said first and second ends of said helical web such that each of said surfaces of said first and second ends of said helical web is mateable with an oppositely facing surface of an adjacent one of said plurality of integrally molded like modules as mated end-to-end to form said plastic screw conveyor.

Claim 13

The screw conveyor of claim 8 wherein said helical web has a predetermined thickness and said predetermined length by which each of said first and second ends of said helical web extends axially outwardly of said first and second ends of said central tube, respectively, is about one half of said predetermined thickness of said helical web, and further wherein said first and second ends of each said helical web lie in a radial plane.

Claim 14

The screw conveyor of claim 2 wherein said integral portion formed at each of said first and second ends of said central tube is a circular groove.

Claim 15

The screw conveyor of claim 12 wherein said sealing engaging measn includes an O-ring disposed in said circular grooves of adjacent ones of said plurality of like modules mated end-to-end to form said screw conveyor.

Claim 16

The screw conveyor of claim 9 wherein said integral portion formed at each one of said first and second ends of said central tube is a circular groove.

Claim 17

The screw conveyor of claim 14 wherein said sealing engaging means includes an O-ring disposed in said circular grooves of adjacent ones of said plurality of like modules mated end-to-end to form said screw conveyor.