US 4,397,230 AGranted

Screw press improvements

OwnerArthur J. Hunt, Arthur J. Hunt, Jr.inventors

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Abstract

A predrainer type screw press for dewatering highly liquid materials having a feed and pressing screw in which the body of a portion of the feed section of the press is cylindrical and the body of a portion in the pressing section of the press is frusto conical having its small diameter end contiguous with the cylindrical body and of a smaller diameter. The feed portion of the screw is partially surrounded by a bar screen for permitting draining of free run liquids from a material to be dewatered. A pressure assisted overflow in the input hopper is provided to limit the material head in the hopper to prevent slippage and ensure positive feed. Baffles are provided to absorb energy from input material having a high velocity to prevent sticking of material to the screw. Pressing section filter screens are hinged to open out for easy access for cleaning and have a liquid tight seal at the ends when closed.

Claims17

Dependent claims

In a predrainer type screw press for dewatering highly liquid material having low solid content;

heavy, spongy or viscous materials;
and material fed under pressure, the improvements comprising:
an input feed section of said screw press;
a cylindrical material pressing section having an outlet end;
a rotatable feed and compression screw having a first cylindrical body concentrically disposed in said feed section and a second frusto conical shaped body concentrically disposed in said material pressing section, said second body contiguous with said first body, the diameter of said first body greater than the diameter of said second body at the point of contiguity, said second body tapering outward from said point of contiguity, and a screw thread continuously disposed helically around the surface of said first and second bodies, the slope of said second body selected to provide a gradual reduction in volume of the flights of said screw thread from said point of contiguity to said outlet end, the diameter of said second body at said point of contiguity selected to produce a pinch point at a desired location along said feed screw in said material pressing section;
an inlet throat section disposed directly into said input feed section over said first body portion of said feed and compression screw;
and
an input filter screen disposed around said screw thread partially over the length of said first cylindrical body, said screen having openings therein to permit free run liquid to drain therethrough.

5 more elements

A predrainer type screw press having positive feed for materials having high liquid content comprising:

a cylindrical cage formed by at least one pair of semicylindrical frames, said frames supporting filter screens for passing liquid extracted from said materials, said pair of frames attached to offset hinges disposed along the lower edges thereto to permit opening said cage for cleaning or replacement of said screens, said frames having forward facing and rearward facing end ribs, each of said end ribs having an inwardly tapering face thereof;
at least two transverse bulkhead members supporting said offset hinges and having circular openings therethrough;
at least two circular rings having an outwardly tapering face, complementary to said inwardly tapering face of said end ribs when in the closed position of said frames, one of said rings disposed around each of said circular openings whereby said end ribs mate with said rings to form a liquid tight joint;
a rotatable compression screw having a frusto conical first body disposed concentrically within said cage with the small end of said body at the forward end thereof and the large end at the rearward end thereof and a screw thread continuously disposed helically around the surface of said first body, the outside diameter of said thread essentially equal to the inside diameter of said cage;
an input feed section of said screw press adjacent the forward end of said cage;
a rotatable feed screw disposed within said feed section having a cylindrical second body concentric with and contiguous to said small end of said first body, said screw thread also continuously disposed helically around the surface of said second body, the diameter of said second body being greater than the diameter of said small end of said first body;
a replaceable bar screen disposed partially around said feed screw over the length of said second body, said screen having openings therein to permit free-run liquid to drain therethrough;
and
an inlet hopper section communicating with said feed section for introduction of said materials.

6 more elements

Dependencies are inferred from the claim text.