HELICAL SCREW CONVEYOR UNIT, WORM SHAFT, WORM EXTRUDER, AND METHOD FOR PROVIDING A WORM SHAFT

Abstract

A helical screw conveyor unit, worm shaft, worm extruder and method for providing a worm shaft, wherein the helical screw conveyor unit is an exchangeable element for a helicoidally or spirally winding helix of a worm shaft, having a main body with a helicoidally winding helix element, wherein the helical screw conveyor unit is serviced with little outlay on servicing, the top side of the lateral surface is concavely curved in shell-like form about the longitudinal axis, and the main body has a radial opening for the leadthrough of a fastening region of a worm shaft shank, the helix element has at most one half of one helix turn, the the main body lateral surface has an inner surface for being seated on the fastening region, and the helical screw conveyor unit has at least one fastening element for detachably fastening the main body to the fastening region.

Claims

1. A helical screw conveyor unit configured as an exchangeable element for a helicoidally or spirally winding helix of a worm shaft, having a main body extending along a longitudinal axis, the main body having two axial end regions and a lateral surface that connects the end regions to one another, at least one helicoidally winding helix element being arranged on a top side of the lateral surface and extending radially outward away from the top side, wherein the top side of the lateral surface is concavely curved in shell-like form about the longitudinal axis, and the main body has a radial opening, the radial opening being configured such that a fastening region of a shank of the worm shaft can be led through the opening in a direction perpendicular to the longitudinal axis and can be arranged in a cavity formed by the main body, the helix element has at most one half of one helix turn, the lateral surface of the main body has an inner surface configured for being seated on the fastening region, and the helical screw conveyor unit has at least one fastening element configured for detachably fastening the main body to the fastening region.

2. The helical screw conveyor unit as claimed in claim 1, wherein the main body runs in the shape of a semicircle or in the shape of a half-shell about the longitudinal axis, and the helix element has one half of one helix turn.

3. The helical screw conveyor unit as claimed in claim 1, wherein the inner surface of the main body is shaped such that, as a result of the inner surface of the main body being seated on the fastening region of the worm shaft, the orientation of the helix element of the helical screw conveyor unit on the worm shaft is defined, and radial mobility of the main body on the worm shaft is at least restricted.

4. The helical screw conveyor unit as claimed in claim 3, wherein, for the orientation of the helix element on the worm shaft, the inner surface of the lateral surface has a contour of complementary shape with respect to the fastening region of the shank.

5. The helical screw conveyor unit as claimed in claim 2, wherein the helix element is shaped such that, as a result of the inner surface of the main body being seated on the fastening region of the worm shaft, the helix element is at least substantially oriented so as to continue the course of the helicoidally or spirally winding helix of the worm shaft.

6. A worm shaft for use in a worm extruder, having a shank which extends along a longitudinal axis and which has a helicoidally or spirally winding helix, comprising at least one helical screw conveyor unit as claimed in claim 1, and at least one fastening means configured for detachably fastening the fastening element.

7. The worm shaft as claimed in claim 6, wherein the fastening means is configured to interact with the fastening element of the helical screw conveyor unit such that the helical screw conveyor unit is detachably fastenable to the fastening region of the worm shaft.

8. The worm shaft as claimed in claim 6, wherein the fastening region of the worm shaft is shaped such that a radial movement of the main body seated on the fastening region is at least restricted.

9. The worm shaft as claimed in claim 6, comprising at least two fastening regions which are formed by at least one recess or at least one groove of the otherwise cylindrical shaft body element and which are arranged so as to be radially and axially offset with respect to one another.

10. The worm shaft as claimed in claim 6, wherein the shank has a cylindrical shaft body and the fastening region, the fastening region being assigned to a support region, configured for supporting the main body of the helical screw conveyor unit, of the shank and having a cross-sectional diameter smaller than that of the cylindrical shaft body.

11. The worm shaft as claimed in claim 10, wherein the support region is arranged eccentrically.

12. The worm shaft as claimed in claim 10, wherein the support region has at least two helical screw conveyor units each having a configuration of the helical screw conveyor unit, the helical screw conveyor units being arranged such that the helical elements of the helical screw conveyor units continue the course of the shaft body helix of the cylindrical shaft body and, with this, form a common shaft body helix unit.

13. The worm shaft as claimed in claim 10, wherein the worm shaft has at least two helical screw conveyor units each having a configuration of the helical screw conveyor unit which are in each case arranged adjacent to one another and together form one full helix turn that fully encircles the shank once.

14. A worm extruder for dewatering a suspension having an extruder chamber in which a worm shaft having a helicoidally winding helix element is mounted so as to be rotatable about its longitudinal axis, wherein the worm shaft is configured as claimed in claim 6 the shank of the worm shaft having at least two helical screw conveyor units, and the helical screw conveyor units each having a configuration of the helical screw conveyor unit.

15. A method for providing a worm shaft configured for use in a worm extruder, wherein a helical screw conveyor unit configured as claimed in claim 1 is arranged on the fastening region and is detachably fastened to the fastening region by way of the fastening element assigned to the helical screw conveyor unit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0049] As already discussed above, there are various possibilities for the advantageous embodiment and refinement of the teaching of the present invention. In this regard, reference is made firstly to the claims that are dependent on claim 1 and claim 6, and secondly, further embodiments, features and advantages of the present invention will be discussed in more detail below, inter alia on the basis of the exemplary embodiment illustrated by FIGS. 1 to 7.

[0050] In the figures:

[0051] FIG. 1 shows, in a perspective illustration, a longitudinal section through a first exemplary embodiment of a worm shaft according to the present invention, having a helical screw conveyor unit according to the present invention arranged detachably thereon, which helical screw conveyor unit is exchangeable in accordance with the method of the present invention;

[0052] FIG. 2 shows the worm shaft from FIG. 1 in a longitudinal sectional illustration;

[0053] FIG. 3 shows a side view of the worm shaft from FIG. 1;

[0054] FIG. 4 shows a detail view of the front region of the worm shaft from FIG. 2;

[0055] FIG. 5 shows a cross section through the helical screw conveyor unit from FIG. 1 along the line B-B shown in FIG. 3;

[0056] FIG. 6 shows the worm shaft from FIG. 1 in an exploded illustration; and

[0057] FIG. 7 shows an exemplary embodiment of a worm extruder according to the present invention with the worm shaft from FIG. 1.

[0058] Identical or similar embodiments, elements or features are denoted by identical reference designations in FIGS. 1 to 7.

BEST WAY OF IMPLEMENTING THE INVENTION

[0059] FIG. 1 shows an exemplary embodiment of a helical screw conveyor unit 100 for a worm shaft 200. The helical screw conveyor unit 100 has a main body 10 that extends along a longitudinal axis L. The main body has two end regions which extend perpendicularly with respect to the longitudinal axis, in other words are situated opposite one another in the direction of the longitudinal axis. The end regions 12, 14 are connected to one another by a lateral surface, with at least one helicoidally winding helix element 30 being arranged around a top side 16 or outer surface of the lateral surface.

[0060] In the exemplary embodiment shown in FIGS. 1 to 3, the worm shaft 200 has multiple, for example two, helix elements 30. For a connection of the helix elements 30 with an accurate fit, these may be welded to one another and jointly ground.

[0061] The at least one helix element 30 has a partial helix turn, in particular one quarter to one half of one helix turn. The main body is concavely curved, that is to say inwardly arched, and has a radial opening 20. In other words, the main body is hollow and runs in curved fashion around the longitudinal axis L. The main body preferably runs in the shape of a circular segment, for example in the manner of a half-shell, around the longitudinal axis L.

[0062] The helical screw conveyor unit 100 is configured for exchangeable installation in a worm shaft 200, preferably in a worm shaft 200 of a worm extruder 300 that is configured for dewatering digestate obtained by anaerobic digestion of organic material.

[0063] FIG. 6 shows an exploded illustration of the worm shaft 200. Said worm shaft has four helical screw conveyor units 100 which together form two encircling helices. Respectively adjacent helical screw conveyor units 100 are arranged so as to be radially offset with respect to one another by 180 degrees, that is to say mirror-symmetrically. For the detachable fastening of the main body 100 to the fastening regions 40 of the support region 210, the helical screw conveyor units each have two socket head screws 34. The fastening regions 40 are shaped in the manner of a partial square, or are of rectangular shape. Those regions of the support region 210 which are situated opposite the helical screw conveyor units 100 or opposite the fastening regions 40 are configured as filler bodies. These protect and stabilize the support region 210. Said filler bodies may be fixedly connected to the support region 210, for example formed integrally with the support region 210, or detachably fastened to the support region 210. The filler bodies are concavely curved about the longitudinal axis L.

[0064] As shown in FIG. 7, the worm extruder 300 has an inner worm shaft 200, with helicoidally winding helix elements 30, 210 which extend away outward, and has a screen drum 340 which encases the worm shaft 200. The screen drum 340 may have pivotable screen shells, allowing easy access to the worm shaft and a fast exchange of screen parts and wearing parts.

[0065] For exchangeable installation in a worm shaft 200, the helical screw conveyor unit 100 has [0066] an inner surface 18, configured for receiving a support region 210 of a shank 230, on the lateral surface of the main body 10, and [0067] at least one fastening element 34 configured for detachably fastening the inner surface 18 to the support region 210.

[0068] The helical screw conveyor unit 100 is thus a detachably fastenable or exchangeable element for a worm shaft 200.

[0069] In an exemplary embodiment of the present invention that is not shown here, the worm shaft 200 may have exclusively exchangeable helix elements 30. It is alternatively possible, as shown in FIGS. 1 to 7, for only a partial region, for example a front region that is situated close to a press cake outlet 350 in a use position, of the worm shaft 200 to be configured as an exchangeable helical screw conveyor unit 100.

[0070] The worm shaft shown in FIGS. 1 to 7 has not only the exchangeable helical screw conveyor unit 100 but also a shank 230 with a cylindrical shaft body and with a shaft body helix 240 winding helicoidally around the shank 230. In the region of the cylindrical shaft body, the shaft body helix 240 is non-detachably connected to the shank 230, for example formed integrally with the shank 230 or welded to the shank 230.

[0071] The support region 210 of the helical screw conveyor unit 100 may be non-detachably connected, for example using the technique of welding, for example by means of a root seam 232, to the cylindrical shaft body. Alternatively, the support region 210 may also be formed integrally with the cylindrical shaft body of the shank 230.

[0072] The helical screw conveyor units 100 are arranged such that the helix elements 30 continue the course of the shaft body helix 240 of the cylindrical shaft body, and with this form a common shaft body helix unit.

[0073] The main body 10 of the helical screw conveyor unit 100 is concavely curved. Here, the main body may be configured such that, in the use position of the worm shaft 200, the support region 210 is fully encased (not shown) by the main bodies of the helical screw conveyor units 100 arranged on the support region 210. For example, in each case two helical screw conveyor units 100 configured as half-shells may fully encase the shaft body element 210.

[0074] Alternatively, the main body 10 may be a foot element 32 of the helix element 30, which foot element is arranged at the radially inner region of the helix element 30 and can be exchangeably arranged in a fastening region 40, configured as a groove, of the support region 210.

[0075] In the exemplary embodiment shown in FIGS. 1 to 7, the helix frequency of the helix elements 30 is identical to the helix frequency of the shaft body helix 240. It would however also be possible for the helix frequency or the pitch of the helix elements 30 to increase in relation to the helix frequency of the shaft body helix 240.

[0076] For the rotatable mounting of the worm shaft 200 in the worm extruder 300, said worm shaft has at least one rotary bearing 250. In order to relieve the transmission of the worm extruder 300 of radial and axial forces, the worm shaft 200 may have a double bearing configuration. This allows longer service lives of the worm extruder 300.

[0077] A preferred material for the helical screw conveyor unit 100 of the type presented above, and for the worm shaft 200 of the type presented above, is steel.

LIST OF REFERENCE NUMERALS

[0078] 10 Main body, in particular foot element of the helix element 30 [0079] 12 First end region of the main body, in particular first end region, extending perpendicular to the longitudinal axis, of the main body [0080] 14 Second end region of the main body, in particular second end region, extending perpendicular to the longitudinal axis, of the main body [0081] 16 Top side, in particular outer side, of the lateral surface of the main body 10 [0082] 18 Inner side of the lateral surface of the main body 10 [0083] 20 Radial or concave opening of the main body 10 [0084] 30 Helix element of the helical screw conveyor unit 100 [0085] 34 Fastening element of the helix element 30 [0086] 40 Fastening region, in particular U-shaped fastening region, square or receiving groove, of the main body 10 [0087] 42 Filler body [0088] 100 Helical screw conveyor unit [0089] 200 Worm shaft or conveyor worm or extruder worm, in particular rod-like worm shaft shank with helicoidally or spirally winding helix elements 240, 30 [0090] 210 Shaft body element, or support region, configured for supporting the main body 10 of the helical screw conveyor unit 100, of the worm shaft shank 230, in particular shank seating region or support region of the shank 230 of the worm shaft 200 [0091] 212 Fastening means, in particular thread, of the shaft body element 210 [0092] 230 Shank or rod-like main body of the worm shaft 200, in particular with cylindrical shaft body and with support region 210 configured for supporting the main body 10 of the helical screw conveyor unit 100 [0093] 232 Weld seam, in particular root seam, for connecting the cylindrical shaft body 230 to the main body 10 [0094] 240 Spirally or helically or helicoidally winding shaft body helix, or helix element, of the worm shaft 200 [0095] 250 Rotary bearing (cf. FIG. 4) [0096] 300 Worm extruder [0097] 340 Screen drum [0098] 350 Press cake outlet [0099] 360 Digestate inlet [0100] 370 Resistance, in particular counterpressure cone [0101] L Longitudinal axis