AN INDIRECTLY HEATED ELECTRICAL ROTARY KILN AND METHODS OF REPLACING A HEATING ELEMENT THEREOF

Abstract

An indirectly heated electrical rotary kiln including a longitudinal inner shell for conveying process material therethrough, the inner shell being rotatable about its longitudinal axis. The rotary kiln further includes a stationary shroud arranged along the length and around the cross-sectional perimeter of the inner shell, thereby surrounding said inner shell, and a shroud module detachable from the remaining shroud, and formed as a longitudinal section and a cross-sectional perimeter segment of the shroud. The rotary kiln further includes an electrical heating element provided on the shroud module on an inside of the shroud, said heating element being configured to heat the inner shell, when in use. Methods for replacing a heating element of the rotary kiln are also disclosed.

Claims

1.-17. (canceled)

18. An indirectly heated electrical rotary kiln, comprising: a longitudinal inner shell configured for conveying process material therethrough so as to be subjected to thermal treatment, when in use, the inner shell being rotatable about its longitudinal axis a stationary shroud arranged along the length and around the cross-sectional perimeter of the inner shell, thereby surrounding said inner shell, wherein the rotary kiln comprises a shroud module formed as a longitudinal section and a cross-sectional perimeter segment of the shroud, wherein said shroud module is detachable from the remaining shroud, and wherein the rotary kiln further comprises an electrical heating element provided on the shroud module on an inside of the shroud, said heating element being configured to heat the inner shell, when in use.

19. The rotary kiln according to claim 18, wherein the shroud module comprises a plurality of heating elements provided at a distance from the inner shell, along the cross-sectional perimeter thereof.

20. The rotary kiln according to claim 19, wherein the shroud module comprises a plurality of sockets configured for detachably operationally coupling with corresponding heating elements.

21. The rotary kiln according to claim 19, wherein the heating elements extend for a distance along the length of the inner shell.

22. The rotary kiln according to claim 18, wherein an internal shape of the shroud, at least at a position of the shroud module, conforms with an external shape of the inner shell at a distance therefrom.

23. The rotary kiln according to claim 18, wherein the shroud module extends laterally along a bottom side the inner shell.

24. The rotary kiln according to claim 18, wherein the shroud module extends vertically along a lateral side of the inner shell.

25. The rotary kiln according to claim 24, wherein the shroud module extends vertically along a lateral side of the inner shell, at least on a side towards which the process material is pushed by the rotation of the inner shell.

26. The rotary kiln according to claim 25, wherein the shroud module extends vertically along a lateral side of the inner shell only on a side towards which the process material is pushed by the rotation of the inner shell.

27. The rotary kiln according to claim 18, wherein the shroud module extends over at least a 90 deg cross-sectional perimeter segment of the shroud below a longitudinal central axis of the inner shell

28. The rotary kiln according to claim 18, wherein the shroud module is retractable from the remaining shroud in a lateral direction away from the inner shell.

29. The rotary kiln according to claim 18, wherein the shroud module comprises rollers (7) or wheels on which it may be supported for retracting said shroud module away from the remain shroud.

30. The rotary kiln according to claim 18, characterized by further comprising a plurality of shroud modules provided along a length of the kiln, suitably spaced apart from each other.

31. The rotary kiln according to claim 18, characterized by further comprising a pair of shroud modules provided on opposing lateral sides of the inner shell, said pair of shroud modules suitably being aligned with respect to each other along the length of the kiln.

32. The method of replacing a heating element of the rotary kiln according to claim 18, characterized by comprising the steps of: detaching a first shroud module from the remaining shroud, said first shroud module having at least a first heating element; replacing said at least first heating element with at least a second heating element, and re-attaching the first shroud module with the at least second heating element to the remaining shroud, while simultaneously operating the rotary kiln.

33. The method according to claim 32, characterized by further comprising, after detaching and prior to re-attaching the first shroud module, the steps of: attaching a dummy shroud module to the remaining shroud so as to cover an opening thereof from which the first shroud element was detached, and detaching the dummy shroud module form the remaining shroud so as to expose said opening into which the first shroud element may be reattached.

34. A method of replacing a heating element of the rotary kiln according to the claim 18, comprising the steps of detaching a first shroud module having at least a first heating element from the remaining shroud, and attaching a second shroud module with at least a second heating element to the remaining shroud, while simultaneously operating the rotary kiln.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In the following the disclosure will be described in greater detail by means of preferred embodiments with reference to the accompanying drawings, in which

[0041] FIG. 1 is a schematic cross-sectional representation of a rotary kiln according to an embodiment of the present disclosure, in which a shroud module is attached to the remaining shroud;

[0042] FIG. 2 is a schematic cross-sectional representation of the rotary kiln of FIG. 1 with the shroud module being retracted away from the remaining shroud;

[0043] FIG. 3 is schematic representation of a section of a rotary kiln according to an embodiment of the present disclosure illustrated as a perspective view;

[0044] FIG. 4a is a schematic representation of a shroud module, and

[0045] FIG. 4b is a schematic representation of a dummy module.

DETAILED DESCRIPTION OF THE DISCLOSURE

[0046] FIG. 1 illustrates a schematic cross-sectional representation of a rotary kiln 1 according to an embodiment of the present disclosure, as seen long the length of the kiln 1. A stationary shroud 4 is arranged along the length and around the perimeter of an inner shell 2. FIG. 1 represents the rotary kiln 1 during operation, i.e., the inner shell is rotated about its longitudinal axis in the direction of the arrow in centre of inner shell. Process material 3 is fed into, and advanced through the inner shell 2, while being subjected to thermal treatment by the heat produced by the heating elements 6. The rotation of the inner shell 2 pushes the process material 3 towards a lateral side of the inner shell 2.

[0047] The rotary kiln 1 comprises a shroud element 5 forming a cross sectional perimeter segment of the shroud 4. Although not seen form FIG. 1 the shroud element 5 also forms a longitudinal section of the shroud 4. Moreover, the shroud element 5 extends laterally below and vertically along a lateral side of the inner shell 2 towards which the rotation of the inner shell 2 pushes the process material. In the arrangement of FIG. 1, the internal shape of the shroud 4, including the that of the shroud module 5, conforms with the external shape of the inner shell 2. In the arrangement of FIG. 1, the shroud element 5 extends over a 90 deg perimeter segment of the shroud 4.

[0048] The shroud element 5 comprises a plurality of heating elements 6 along the cross-sectional perimeter of the inner shell 2, at a distance therefrom. Although not illustrated in FIG. 1 the heating element 6 are suitably operationally coupled in corresponding sockets arranged on the shroud element 5. Also not seen from FIG. 1, the heating elements 6 extend for a distance along the length of the inner shell 2.

[0049] FIG. 2, in turn, illustrates a schematic cross-sectional representation of the rotary kiln shown in FIG. 1 with the shroud module 5 retracted away from the remaining shroud 4. Particularly, the shroud module 5 has been retracted away in a lateral direction away from the remaining shroud 4. FIG. 2 also illustrates rollers 7 on which the shroud module 5 may be supported during retraction. For example, such rollers 7 could be fixed to the shroud module 5, or alternatively, temporarily attached to the shroud module 5 for the removal thereof.

[0050] FIG. 3 shows a section of a rotary kiln according to an embodiment of the present disclosure as a schematic representation illustrated as a perspective view. The inner shell 2 of the rotary kiln 1 is housed within the shroud 4 in a manner similar to that of the drawings discussed above. The rotary kiln 1 comprises multiple shroud modules 5 arranged longitudinally one after another, each shroud module 5 forming a longitudinal section and a cross-sectional perimeter segment of the shroud 4. Particularly, FIG. 3 shows one of the shroud modules 5 being detached from the remaining shroud 4 and retracted away therefrom. The shroud modules 5 are supported on rollers 7 (not denoted in FIG. 3) allowing the shroud modules 5 to be easily drawn out of the remain shroud 4. Moreover, the shroud modules 5 are equipped with flanges 8 for positioning and securing the shroud modules 5 to the remaining shroud 4. For example, the flanges may have openings, through which pins protruding from the remaining shroud 5 extend, when the shroud module 5 is properly positioned in place.

[0051] Although the arrangement of FIG. 3 shows shroud modules 5 being positioned one after another along the length of the rotary kiln 1, the shroud modules 5 could alternatively, or additionally, be spaced apart from each other. In such a case, the remaining shroud 4 may advantageously extend into the space between the spaced apart shroud modules 5. Moreover, although the arrangement of FIG. 3 shows the shroud modules 5 being arranged on a single lateral side of the rotary kiln 1, shroud modules 5 could be provided on both lateral sides of the rotary kiln 1. In such a case, shroud modules may could be arranged as pairs on laterally opposing sides of the rotary kiln 1.

[0052] It should also be noted that, for the purpose of clarity, FIG. 3 does not illustrate heating elements of the shroud modules 5.

[0053] FIG. 4a illustrates a shroud module 5 of the arrangement of FIG. 3 as seen as a side view. Particularly, the shroud module 5 is equipped with heating elements 6. FIG. 4b, in turn, illustrates a dummy module 5 which may be used to cover an opening of a detached shroud element 5, while said shroud element 5 is being serviced. Particularly, the dummy module 5 is not equipped with heating elements.

LIST OF REFERENCE NUMERALS

[0054] 1 rotary kiln [0055] 2 inner shell [0056] 3 process material [0057] 4 shroud [0058] 5 shroud module [0059] 5 dummy module [0060] 6 heating element [0061] 7 roller [0062] 8 flange