Solid bowl screw centrifuge with mixing blades or paddles arranged on the screw shaft

Patent metadata

Field	Value
Publication number	US-12290824-B2
Application number	US-202017607124-A
Country	US
Kind code	B2
Filing date	Apr 24, 2020
Priority date	Apr 29, 2019
Publication date	May 6, 2025
Grant date	May 6, 2025

Abstract

A solid bowl screw centrifuge includes a housing and a rotor rotatably mounted in the housing. The centrifuge has a rotatable drum having an axis of rotation, the drum having a cylindrical section having a length L 1 and a conical section having a length L 2 . The centrifuge also has a first inlet for feeding a suspension to be processed into the drum and a liquid outlet arranged in the cylindrical section of the drum and a solids outlet arranged in the conical section of the drum. A screw is arranged in the drum and rotatable at a differential speed relative to the rotatable drum, the drum and the screw together forming the rotor. The centrifuge also a second inlet for supplying an additive to a solid phase within the drum.

First claim

The invention claimed is:

1. A solid bowl screw centrifuge, comprising:
a housing;
a rotor rotatably mounted in the housing;
a rotatable drum having a rotational axis, wherein the rotatable drum has a cylindrical section having a length L 1 and a conical section having the length L 2 ;
at least one first feed configured to supply a suspension to be processed into the rotatable drum;
at least one liquid drain arranged in the cylindrical section of the rotatable drum;
at least one solid discharge arranged in the conical section of the rotatable drum;
a screw having windings and a screw shaft, wherein the screw is rotatable relative to the rotatable drum at a differential speed and is arranged in the rotatable drum, wherein the rotatable drum and the screw jointly form the rotor;
a second feed configured to supply an additive to a solid phase inside the rotatable drum, wherein the second feed is arranged coaxially to the rotational axis, and wherein the second feed protrudes into an interior of the screw shaft opposite to the at least one first feed;
a line radially extending from the second feed in a direction of a casing of the rotatable drum, wherein the line is configured to deflect the additive, and wherein the line has an orifice opening located in a region between the screw shaft and the casing of the rotatable drum; and
mixing blades or mixing paddles, in addition to the windings of the screw, are arranged along a wall of the screw shaft.

2. The solid bowl screw centrifuge of claim 1 , wherein the second feed is arranged at least partially concentrically to the rotational axis of the rotatable drum.

3. The solid bowl screw centrifuge of claim 1 , wherein the second feed has a feed pipe protruding into the screw shaft of the screw, and the second feed has an apparatus configured to radially discharge the additive from the screw via the orifice opening.

4. The solid bowl screw centrifuge of claim 3 , wherein the first feed has a feed pipe protruding into the screw shaft of the screw, and the first feed has an apparatus configured to radially discharge the suspension to be processed from the screw via a further orifice opening, wherein the orifice opening of the second feed is arranged between the further orifice opening of the first feed and the at least one solid discharge.

5. The solid bowl screw centrifuge of claim 4 , wherein the orifice opening of the second feed is arranged in the conical section.

6. The solid bowl screw centrifuge of claim 4 , wherein the feed pipe of the second feed is arranged on a side of the solid bowl screw centrifuge opposite to the feed pipe of the first feed.

7. The solid bowl screw centrifuge of claim 3 , wherein the apparatus for radially discharging the additive to be processed is a pipeline or a distributor, wherein the distributor is formed as a chamber inside the screw shaft, into which the feed pipe of the first feed opens and which has the further orifice opening in the wall of the screw shaft.

8. The solid bowl screw centrifuge of claim 1 , further comprising:
an immersion disk, which protrudes radially out of a surface of the screw shaft, is arranged between the orifice opening of the second feed and the further orifice opening of the first feed.

9. The solid bowl screw centrifuge of claim 8 , wherein the immersion disk is arranged in a transition region, in which the cylindrical section merges into the conical section.

10. The solid bowl screw centrifuge of claim 1 ,
wherein the mixing blades or mixing paddles protrude out of the screw shaft into an intermediate space between the screw shaft and the rotatable drum and are arranged in the conical section.

11. The solid bowl screw centrifuge of claim 3 , wherein the feed pipe of the second feed is rotatably mounted.

12. A method, comprising:
providing a solid bowl screw centrifuge, which comprises
a housing;
a rotor rotatably mounted in the housing;
a rotatable drum having a rotational axis, wherein the rotatable drum has a cylindrical section having a length L 1 and a conical section having the length L 2 ;
at least one first feed configured to supply a suspension to be processed into the rotatable drum;
at least one liquid drain arranged in the cylindrical section of the rotatable drum;
at least one solid discharge arranged in the conical section of the rotatable drum;
a screw having windings and a screw shaft, wherein the screw is rotatable relative to the rotatable drum at a differential speed and is arranged in the rotatable drum, wherein the rotatable drum and the screw jointly form the rotor;
a second feed configured to supply an additive to a solid phase inside the rotatable drum, wherein the second feed is arranged coaxially to the rotational axis, and wherein the second feed protrudes into an interior of the screw shaft opposite to the at least one first feed;
a line radially extending from the second feed in a direction of a casing of the rotatable drum, wherein the line is configured to deflect the additive, and wherein the line has an orifice opening located in a region between the screw shaft and the casing of the rotatable drum; and
mixing blades or mixing paddles, in addition to the windings of the screw, are arranged along a wall of the screw shaft;

supplying a liquid, gaseous, or solid additive via the second feed to the conical section of the rotatable drum;
mixing the solid phase in the conical section of the rotatable drum with the liquid, gaseous, or solid additive; and
using the conical section of the rotatable drum, at least in regions, as a mixing zone, in which mixing of the solid phase with the supplied additive occurs.

13. The method of claim 12 , wherein the method processes a stillage to form a dry stillage, wherein the stillage is supplied via the first feed to the solid bowl screw centrifuge and wherein processing of the stillage to form a thin stillage and a solid phase occurs in the solid bowl screw centrifuge, wherein a syrup obtained from the thin stillage during the processing in the solid bowl screw centrifuge is supplied to the solid phase as the additive in the drum via the second feed.

14. The method of claim 13 , wherein the syrup from the thin stillage is obtained by an evaporator and a downstream 3-phase separator while additionally obtaining corn oil.

Assignees

• Gea Mechanical Equipment Gmbh

Inventors

• Aagaard Poul-Erik

Classifications

• B04B2001/2041

  with baffles, plates, vanes or discs attached to the conveying screw · CPC title

• B04B11/02

  Continuous feeding or discharging; Control arrangements therefor · CPC title

• B04B1/20 Primary

  discharging solid particles from the bowl by a conveying screw coaxial with the bowl axis and rotating relatively to the bowl · CPC title