METHOD AND APPARATUS FOR CONVEYING HOT CALCINED RAW MEAL

Abstract

A slide plate 10 for a slide 1 for Geldart group C materials with a longitudinal axis 2, an up-facing surface 11 for supporting the Geldart group C material, a lower surface 13, a front-side surface 12 and a rear-side surface 14 may have a significantly reduced slope if the slide plate 10 is made of a ceramic refractory, wherein the slide plate has a number of through holes 20 providing a fluid communication between fluid inlets 23 in the lower surface 13 and fluid outlets 21 in the up-facing surface 11.

Claims

1.-15. (canceled)

16. A slide plate dimensioned to be inserted into a slide of a conveyor configured to convey Geldart group C materials, wherein: the slide plate has a longitudinal axis, an up-facing surface configured to support the Geldart group C material, a downward-facing surface, a front-end surface, and a rear-end surface, the slide plate is made of a ceramic refractory, the ceramic refractory has through holes configured to provide fluid communication between fluid inlets in the lower surface and fluid outlets in the up-facing surface, and a fluid outlet of at least one of the through holes is closer to the front-end side surface than a fluid inlet of said at least one of the through holes.

17. The slide plate of claim 16, wherein at least one of the through holes is dimensioned as a slot with a slot width w and a slot clearance d, wherein the slot width w extends substantially perpendicularly to the longitudinal axis in a direction within an angle of , {45,40,30,15,10,5,2.5,1,0} to the longitudinal axis, and wherein the slot width w is greater than the slot clearance d.

18. The slide plate of claim 16, wherein the slide plate has boundaries limiting at least one of the through holes in a conveying direction and wherein a slot clearance d between first and second boundaries is below 0.75 mm.

19. The slide plate of claim 1, configured to have a pressure gradient p.sub. between the up-facing surface and the downward-facing surface smaller than or equal 2 kPa.

20. The slide plate of claim 1, wherein the down-facing surface has at least one recess and/or protrusion providing a first stop surface that faces towards the front-end surface and/or a second stop surface that faces towards the rear-end surface, wherein said first stop surface and/or said second stop surface is dimensioned to limit a movement in a direction parallel to the longitudinal axis.

21. A conveyor slide configured to convey hot Geldart group C materials, wherein the slide comprises at least one slide plate according to claim 1.

22. The slide of claim 21, wherein: the slide comprises a housing with a housing wall, wherein the housing wall encloses a channel, the housing has a slide plate support that supports the at least one slide plate in the channel, the slide plate separates at least a segment of the channel into an upper channel and a lower channel, wherein the lower surface provides a ceiling of the lower channel and wherein the up-facing surface provides a bottom of the upper channel and wherein the through holes provide fluid communication between the upper channel and the lower channel.

23. The slide of claim 22, wherein the slide plate is located in between the lower channel and the upper channel and provides a boundary between the lower channel and the upper channel, wherein at least a portion of the up-facing surface provides a bottom surface of the upper channel, and configured such that a gas flow through the slide plate is below a value represented by a ratio of half a cubic meter of gas under normal conditions per second to an area of the bottom surface of the upper channel, wherein the normal conditions are defined by a standard pressure p.sub.N=101.325 kPa and a standard temperature T=0 C.

24. The slide of claim 21, further comprising at least one slide plate support, wherein the at least one slide plate is supported by said at least one slide plate support, wherein the slide plate support comprises a refractory cladding thereby defining the width of a channel, wherein a first side portion of the lower surface resides on a first portion of the at least one slide plate support and a second side portion of the lower surface resides on a second portion of the at least one slide plate support, wherein a middle portion of the lower surface is in between a first side portion and a second side portion.

25. The slide of claim 24, wherein the down-facing surface of the at least one slide plate has at least one recess and/or protrusion providing a first stop surface that faces towards the front-end surface and/or a second stop surface that faces towards the rear-end surface, wherein said first stop surface and/or said second stop surface is dimensioned to limit a movement in a direction parallel to the longitudinal axis, wherein the at least one slide plate support has at least one support protrusion and/or support recess engaging into the at least one recess and/or protrusion of the slide plate, respectively, wherein an extension of the at least one support protrusion parallel to the longitudinal axis is at least 1 mm shorter than an extension of the recess of the slide plate into which the at least one support protrusion engages, as measured parallel to the longitudinal axis.

26. The slide of claim 6, wherein the at least one slide plate includes multiple slide plates, the up-facing surface of the at least one slide plate has a corresponding slope smaller than 25 relative to the horizon, and/or the most upstream of the multiple slide plates has a corresponding slope that is greater than that of at least one downstream slide plate of the multiple slide plates.

27. The slide of claim 22, wherein the upper channel comprises at least one gas opening that is connected via at least one valve to a reservoir of compressed gas.

28. A method for conveying a Geldart group C material, the method comprising at least: depositing the Geldart group C material on the up-facing surface of the slide of claim 6, and providing a gas flow of less than half a cubic meter of gas under normal conditions per second and per area of a slide surface through through-holes to an up-facing surface of the slide.

29. The method of claim 28, further comprising controlling a blower of the conveyor to provide a gas pressure gradient p.sub. between the up-facing surface and the downward-facing surface of the at least one slide plate, wherein said gas pressure gradient is smaller than or equal to 2 kPa.

30. The method of claim 28, wherein the Geldart group C material is calcined, partially calcined, or uncalcined cement clinker raw meal.

31. The slide plate of claim 16, wherein the Geldart group C material is calcined, partially calcined, or uncalcined cement clinker raw meal.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In the following, the invention will be described by way of example, without limitation of the general inventive concept, on examples of embodiment and with reference to the drawings.

[0043] FIG. 1 presents a perspective view of a slide segment of a slide for a Geldart group C material.

[0044] FIG. 2 presents a side view of the slide segment.

[0045] FIG. 3 presents a cross sectional view of the slide segment on the plane A-A as indicated in FIG. 2.

[0046] FIG. 4 presents a longitudinal sectional view of a lower portion of the slide segment.

[0047] FIG. 5 presents a perspective view of a lower portion of the slide segment.

[0048] FIG. 6 presents a side view of another slide segment, which may be combined with the segment of FIGS. 1 and 2.

[0049] FIG. 7 presents a top view of the slide segment of FIG. 6.

[0050] FIG. 8 presents a sectional view of the slide segment of FIGS. 6 and 7 along the plane A-A in FIG. 7.

[0051] Generally, the drawings are not to scale. Like elements and components are referred to by like labels and numerals. For the simplicity of illustrations, not all elements and components depicted and labeled in one drawing are necessarily labels in another drawing even if these elements and components appear in such other drawing.

[0052] While various modifications and alternative forms, of implementation of the idea of the invention are within the scope of the invention, specific embodiments thereof are shown by way of example in the drawings and are described below in detail. It should be understood, however, that the drawings and related detailed description are not intended to limit the implementation of the idea of the invention to the particular form disclosed in this application, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present invention as defined by the appended claims.

DETAILED DESCRIPTION

[0053] The segment of the slide 1 in FIG. 1 may as well be considered as a short slide 1, but in practice mostly a number of the depicted segments may be connected to form a longer slide for a Geldart group C material. Thus, a slide 1 may have a number (at least one) of the depicted segments. The slide 1 extends at least essentially parallel to the longitudinal axis 2 and may be configured to convey a Geldart group C material in the conveying direction 3.

[0054] The slide in FIG. 1 has a housing 30 with a housing wall 31. The housing wall 31 may be, e.g., of sheet metal, being easy to process. The housing wall may preferably have an upper housing portion 311 and a lower housing portion 313, which may be (preferably releasably) attached to each other thereby enclosing a channel with an upper portion 41 and a lower portion 43 (see FIG. 3). As shown, the upper housing portion 311 and the lower housing portion 313 may have an upper flange 351 and a lower flange 353, respectively, enabling to (preferably releasably) attach the upper housing portion 311 and the lower housing portion 313 to each other. In addition or alternatively, the slide 1 may have a front-end flange 36 and a rear end flange 37. Preferably, the front face of the front-end flange 36 may be a at least a portion of a projection of the rear face of the rear end flange 37 parallel to the longitudinal axis 2. This cases to connect slides 1 together by simply connecting the front-end flange 36 of a first slide 1 to a rear-end flange 37 of a second slide 1, thereby forming a correspondingly longer slide 1 and converting the first and the second slides 1 into slide segments. Of course, the rear face of the rear-end flange 37 may as well be a portion of a projection of the front face of the front-end flange 36 parallel to the longitudinal axis 2.

[0055] Inside the housing wall 31 may be an insulation layer 38, as shown in particular in FIGS. 1 and 3. The insulation layer 38 may be, e.g., of a Calcium Silicate material or of any other material having a low heat transfer coefficient. In an example embodiment, the insulation layer 38 may be made of or include microporous insulation material, these materials offer rather low thermal conductivities K in the range of approximately

[00004]$0.020.05\frac{W}{\mathrm{mK}}.$

When using conventional isolation material, the thickness of the insulation layer 38 may be increased accordingly.

[0056] The insulation layer 38 has an upper insulating portion 381 may be located in the upper portion of the housing wall 311 and a lower insulating portion 383 may be located in the lower portion of the housing wall 313. Each of the two insulation portions forms a U-profile with a middle leg to which two side legs may be attached. If mounted, as shown in FIGS. 1 and 3, the free ends of the side legs of the upper insulation portion may face the corresponding free ends of the side legs of the lower insulation portion.

[0057] The housing 30 may preferably have a refractory cladding 50. The upper housing portion may have an upper cladding and the lower portion housing may have a lower cladding. As can be seen in FIG. 4, the refractory cladding 50 protects the optional insulation layer 38 from abrasion by the Geldart group C material. In case the insulation material 38 has been omitted the optional refractory cladding 50 may protect the housing wall 31. Thus, the refractory cladding 50 may be inside the housing wall 31. The optional insulation material 38 may be in between of the refractory cladding 50 and the housing wall 31.

[0058] The lower portion of the refractory cladding may have a U-shaped cross section with a cladding middle leg 531 and two cladding side legs 532. The cladding middle leg 531 may be supported on the up-facing surface of the middle leg of the optional lower insulating portion 383, as shown. In case the insulating portion 383 has been omitted, the cladding middle leg may be supported on or by the bottom of the lower portion of the housing wall 313. The two cladding side legs 532 of the lower portion of the refractory cladding 53, lower cladding side legs 532, for short, may extend towards the upper portion of the housing wall 311. The lower cladding side legs 532 may each provide an up-facing surface. The up-facing surface of the cladding side legs 532 may support a slide plate 10.

[0059] The slide plate 10 extends along the longitudinal axis 2 and has an up-facing surface 11 for supporting a Geldart group C material, such as, e.g., hot calcined raw meal. The slide plate 10 as well has a lower surface 13 (as well referred to as downward-facing surface 13), a front-side surface 12 and a rear-side surface 14. The slide plate 10 may be made of a ceramic refractory.

[0060] The lower surface 13 of the plate 10 has side portions which may reside on the lower cladding side legs 532. Thus, the lower cladding side legs 532 may support the slide plate 10.

[0061] The lower cladding portion and the slide plate 10 may enclose a lower channel 43. For example, the lower channel 43 may be delimited by a center stripe of the lower surface 13 of the slide plate 10, the inwards facing surfaces of the lower cladding side legs 532 and the up-facing surface of the lower cladding middle leg 531 (see FIGS. 4 and 5). The center stripe of the lower surface 13 of the plate 10 may thus be in between of the side portions of the lower surface 13 of the plate 10 residing on the up-facing surfaces of the lower cladding side legs 532 (see FIG. 3).

[0062] As can be seen in FIG. 4 and FIG. 5 the lower cladding side legs 532 may have protrusions 533 engaging in complementary shaped recesses 123 in the lower surface 12 of the slide plate, preventing the slide plate 10 to slide parallel to the longitudinal axis 2. The maximum extension of the protrusions may be slightly smaller than the space provided by the corresponding recess to thereby allow the slide plate 10 to float with the limits given by the distance between the extensions of the protrusions and the recesses on the lower refractory side legs 532. In between of the up-facing surface 11 of the slide plate 10 and the upper cladding side legs may be a gasket.

[0063] The housing may further form an upper channel 41. Like in the depicted example, the housing may have an upper cladding 51. The upper cladding may have an inverted U-shape with a middle leg 511 from which two side legs 512 extend downwards to the up-facing surface of the slide plate 10. The lower side of the middle leg 511 defines the ceiling of the upper channel 41. A portion of the up-facing surface 11 of the slide plate, the so called center stripe of the up-facing surface 11 of the plate 10 provides the bottom of the upper channel 41 and the inward facing sides of the upper cladding side legs 512 define the width of the upper channel 41 and in this example as well the width of the center stripe. The width of the upper channel 41 may be at least essentially the same as the width of the lower channel 43.

[0064] As shown in FIGS. 4 and 5, the slide plate 10 may preferably have a number of through holes 20 extending from an inlet opening 23 in the slide plate's lower surface 13 to an outlet opening 21 in the slide plate's up-facing surface 11. Like in the depicted example embodiment, the through holes 20 may be slots with a slot width w extending at least essentially perpendicular to the longitudinal axis 2. The slot clearance d may be at least essentially constant along the slot width. As can be seen, the slot width w may preferably be a multiple m of the slot clearance d, wherein m may be greater than 1 and not necessarily an integer, i.e., m>1 and mR, wherein R denotes the set of real numbers. The through holes may be inclined in the conveying direction, i.e., the outlet opening 21 may be closer to the front-side surface 12 of the slide plate 10 than the inlet opening 23 of the respective through hole. This inclination of the through holes 20 has shown to reduce the gas flow rate required to maintain the Geldart group C material flowing.

[0065] It has been observed that the particles of Geldart group C materials form brittle but very soft clusters. These clusters may be considered as cohesion bound agglomerates of particulate matter. Without being bound to theorem the reduction of the critical angle may be believed to be caused by a gas cushion being formed by the gas flow between the slide plate and clusters of the bed of particulate matter. Holes, crevasses, or other kind of interstices have been observed to form between these clusters by the gas flow. The gas then flows through these interstices to the upper side of the bed being formed by the particulate material. Thus, the particulate material is not fluidized by the gas flow. The gas cushion so to speak reduces the cohesion of the particulate matter to the slide plate's top surface and hence reduces the friction. In other words, the gas flow via the through holes 20 provides for a reduction of the cohesion of the particulate matter to the top surface 11 of the slide plate 10 and hence reduces the friction between the top surface 11 and the bed of particulate matter. This reduced friction directly translates in a significant decrease of the required minimum slope angle of the slide. Slope angles of or below 25, 20, 15, 12 and 10 have been found to be steep enough to reliably provide for conveying even Geldart group C materials. An increase in gas flow rate through the through holes provides for a reduction of the minimum slope angle for a reliable conveying of Geldart group C materials.

[0066] In operation, a flow of a Geldart group C material may be unloaded to a first end portion of the upper channel 41. The Geldart group C material may thus be deposited on the up-facing surface 11 of the slide plate 10. Further, the lower channel 43 may be provided with a gas pressure p.sub.l, greater than the gas pressure p.sub.u in the upper channel 41, hence preferably p.sub.l>p.sub.u. Due to the pressure gradient p.sub.=p.sub.lp.sub.u, a gas flow through the through holes 20 may be provided. The gas flow reduces the cohesion between the Geldart group C material (or any other particulate matter) and the up-facing surface 11 of the slide plate 10. The Geldart group C material may thus slide down an only slightly inclined slide. Slightly inclined means herein that inclinations of or below 25, 20, 15, 12 and 10 relative to the horizontal can be realized, some experiments showed a possible reduction down to 10 and slightly below this slope. These inclinations may be much smaller than the inclination of the prior art slides, which usually have a slope of at least 60 and contribute to a significant reduction of the construction costs of the corresponding plant.

[0067] Preferably, the housing 10 has an inspection and maintenance opening 60 being shown closed in FIGS. 1, 2, 3, 4 and 5. The opening 60 may as well be used as gas inlet opening to provide a gas flow to the lower channel 43.

[0068] FIGS. 6 to 8 show another slide segment 1 of a Geldart group C material conveying slide. The slide segment of FIGS. 6 to 8 may be mounted and may hence preferably be configured to be mounted to the rear end of a slide segment of FIG. 1. For example, the rear-end flange 37 of the slide segment of FIGS. 1 and 2 may be bolted to the front-end flange 36 of the another slide segment 1 as shown in FIGS. 6 to 8.

[0069] The slide segment in FIGS. 6 to 8 has a housing 30 with an inlet 5 for receiving particulate matter, e.g., a Geldart group C material. As can be seen best in FIG. 8, the inlet 5 may be above a slide plate 110 and enables to feed the particulate matter into an upper channel 41. The bottom of the upper channel 41 may be delimited by slide plates 110 and 10, having through holes 20 which are shown only in FIG. 6, as the section plane A-A extends through an optionally continuous land. The slide plates 110 and 10 may be essentially identical to the slide plates 10 of the slide segment in FIG. 1 to FIG. 3, details of which being depicted in FIGS. 4 and 5 and the description of the slide plates 10 as provided in the context of FIGS. 1 to 5 may be read as well on the slide plates 110 and 10 as shown in FIGS. 6 and 8.

[0070] The slide plate 110 in FIGS. 6 and 8 may be upstream of the slide plate 10 and may have preferably have a steeper slope angle than the downstream slide plate 10. This increased slope angle contributes to an even more reliable operation of the slide and reduced mean slope of the slide. Experiments showed that slide congestions (e.g., due to sticky particulate matter) start always at the upstream end of the slide. Once the particulate matter flows down the slide, lower angles (less steep slopes) may be sufficient to maintain even a Geldart group C material in motion. Thus, the steeper slope angle of the upstream slide plate 110 enables to further reduce the slope angle of subsequent slide plates 10, thereby further reducing the height required to install a slide with a given horizontal extension. In any embodiment the upstream slide plate 110 may have a higher number of through holes and/or through holes with a greater gross section than the immediate or another downstream slide plate. Both measures contribute to increase of the gas flow rate through the upstream slide plate 110 and thereby to reduce the risk of slide congestions.

[0071] Very similar to the slide segment 1 in FIGS. 1 to 3, the upper channel 41 may be delimited to the top and to the sides by a refractory cladding 50 including upper cladding side legs 511 and upper cladding middle legs 512. In between of the outer housing wall 31 and the refractory cladding 50 may preferably be an insulation layer 38 (see FIG. 8).

[0072] The slide plates 110 and 10 in FIG. 8 separate the upper channel 41 from a lower channel 43. Hence the lower channel 43 extends below the slide plates 110 and 10. As well very similar to the lower channel in FIG. 3, the bottom and the sides of the lower channel 3 may be delimited by a lower cladding middle leg 531 in between of two lower cladding side legs 532. Again, an optional insulation layer 38 may preferably be located in between of the housing wall 31 and the portions of the lower cladding.

[0073] The lower channel 43 may extend into a gas inlet 45 and may hence be in fluid communication with the gas inlet 45 (see FIG. 8). By attaching a gas source to the gas inlet 45, a gas can be inserted into the lower channel 43 and thereby a pressure gradient between the lower channel 43 and the upper channel 41 can be provided. Accordingly, a portion of the gas may flow through the through holes 20 to the up facing surface 11 of the slide plates 110, 10 and may reduce the friction between the slide plates 110, 10 and the particulate matter which may have been inserted into the upper channel 41 via the particulate matter inlet 5.

[0074] As already apparent, already a single slide segment 1 be it the slide segment 1 of FIGS. 1 to 3 or the slide segment 1 of FIGS. 6 to 8 may each be used as a slide, if the distance via which material is to be conveyed is sufficiently short. In case the distance is longer, multiple slide segments may be attached to each other to thereby constitute an accordingly longer slide.

[0075] It will be appreciated to those skilled in the art having the benefit of this disclosure that this invention is believed to provide a slide plate and a slide for Geldart Group C materials. Further modifications and alternative embodiments of various aspects of the invention will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only and is provided for the purpose of teaching those skilled in the art the general manner of carrying out the invention. It is to be understood that the forms of the invention shown and described herein are to be taken as the presently preferred embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features of the invention may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this description of the invention. Changes may be made in the elements described herein without departing from the spirit and scope of the invention as described in the following claims.

GENERAL REMARKS

[0076] The terms at least essentially constant, at least essentially the same as or the like as used above are to be understood that constant or the same dimensions, respectively, are preferred, but deviations from a nominal value can be accepted. Typically, acceptable deviations are within one of 20%, 15%, 10%, 5%, 2.5% and 1% wherein lower ranges of deviations are preferred.

[0077] The terms at least essentially parallel, at least essentially perpendicular or at least essentially orthogonal, respectively and the like as used above are used to indicate that parallel or perpendicular (orthogonal), respectively, is preferred but that deviations can be accepted. Typically, acceptable deviations from the intended direction or orientation, whatever applies, may be within one of 30, 20, 15, 10, 5, 2.5 and 1% wherein lower values are preferred.

LIST OF REFERENCE NUMERALS

[0078] 1 slide (segment) for Geldart group C materials (segment of) [0079] 2 longitudinal axis [0080] 3 conveying direction [0081] 5 material inlet. [0082] 10 slide plate [0083] 110 slide plate [0084] 11 up-facing surface of the slide plate [0085] 12 front-end side surface of the slide plate [0086] 13 lower surface/downward-facing surface of the slide plate [0087] 14 rear-end side surface of the slide plate [0088] 20 through hole [0089] 21 fluid outlet [0090] 23 fluid inlet [0091] 30 housing [0092] 31 housing wall [0093] 311 upper portion of housing wall (deliming the upper channel) [0094] 313 lower portion of housing wall (deliming the lower channel) [0095] 351 upper flange [0096] 353 lower flange [0097] 36 front-end flange [0098] 37 rear-end flange [0099] 38 insulation layer [0100] 381 upper insulating portion [0101] 383 lower insulating portion [0102] 41 upper channel [0103] 43 lower channel [0104] 45 gas inlet of lower channel [0105] 50 refractory cladding [0106] 511 upper cladding middle leg [0107] 512 upper cladding side legs [0108] 531 lower cladding middle leg [0109] 532 lower cladding side legs [0110] 533 protrusions [0111] 60 opening