DEVICE AND METHOD FOR DOSING LOOSE MATERIAL

Abstract

The invention relates to a device and a method for metering bulk material (12) with a housing (2) extending along an axis (3) comprising a base plate (4), a cover plate (5) arranged axially at a distance therefrom, and a circumferential wall (6) connecting the base plate (4) and cover plate (5), which enclose a working chamber (7). A rotating cell wheel (28) is arranged in the working chamber (7) with a plurality of cells (33) arranged concentrically around the axis (3) on a number of n circular paths (32.1, 32.2, 32.3, 32.4), wherein the cells (33) of a first circular path (32.4) are arranged with a circumferential offset v to the cells (33) of a further circular path (32.2). The upper sides of the cells (33) facing the lid plate (5) and the lower sides of the cells (33) facing the bottom plate (4) are open and form chambers rotating around the axis (3) together with the lid plate (5) and bottom plate (4).The housing (2) has an inlet opening (8) through which the feed material (12) can be supplied to the cells (33) of the rotary valve (28), and an outlet opening (9) through which the cells (33) of the rotary valve (28) can be emptied. During the rotation of the rotary valve (28), the filled cells (33) enter the area of ​​the outlet opening (9), with each cell (33), together with its cell walls and the outlet opening (9), forming a rotation-angle-dependent partial cross-section A as it enters the housing. To ensure the most continuous possible flow of material during dosing, the invention proposes that the circumferential offset v between a first cell (33) of the first circular path (32.4) that leads in the direction of rotation (38) and a further cell (33) of the subsequent circular path (32.4) that immediately follows in the direction of rotation (38) is determined by the rotational angle.2) is designed such that, at the beginning of the entry of the further cell (33) into the area of ​​the outlet opening (9), the partial cross-section Apart of the first cell (33) corresponds to x * 1 / n of the full cross-section Afull of the first cell (33), where x lies in a range between 0.6 and 1.4.

Description

Field of TechnologyThe invention relates to a device for metering pourable feed material having a housing extending along an axis, comprising a base plate, a cover plate arranged at an axial distance therefrom and a circumferential wall connecting the base plate and cover plate, which circumferential wall enclose a working space in which a cell wheel rotating about the axis is arranged, having a multiplicity of cells arranged concentrically about the axis on a number of n circular paths, wherein the cells of a first circular path are arranged with a circumferential offset from the cells of a further circular path, and wherein the upper sides of the cells facing the cover plate and the lower sides of the cells facing the base plate are formed open and form chambers rotating about the axis with the cover plate and base plate, and wherein the housing has an inlet opening via which the feed material can be supplied to the cells of the cell wheel, and an outlet opening, via which the cells of the cell wheel can be emptied, wherein the filled cells enter the region of the outlet opening during the rotation of the cell wheel and each cell with its cell walls and the outlet opening forms a respective rotation angle-dependent partial cross section A teil produced during the entry.The invention further relates to a method for metering pourable feed material by means of a cellular wheel sluice having a cellular wheel housing and a cellular wheel which rotates within the housing about an axis and which has a multiplicity of cells which are arranged on a number of n circular paths concentrically about the axis, to which the feed material is fed via an inlet opening in the housing and which are emptied via an outlet opening in the housing, wherein the filled cells enter the region of the outlet opening by rotation of the cellular wheel and each cell forms with its cell walls and the outlet opening a respective partial cross section A teil which is dependent on the angle of rotation and which occurs during the entry.Prior ArtFor metering pourable feed material in the amount required for subsequent processes, the use of cellular wheel locks is known. These are usually arranged at the material outlet of a storage container and meter the feed material in the desired quantity into a downstream mechanical or pneumatic conveying device. Suitable feed materials are, in particular, free-flowing and / or free-flowing substances which, with regard to their particle size, range from granules to powders or dusts.EP 1 012 545 B1 describes a device for continuous gravimetric metering and mass flow determination, the metering rotor of which has a plurality of pockets which are arranged on one or more circular paths about the axis of rotation. During the rotation of the metering rotor, the pockets are filled and emptied in alternating sequence. Since the conveying intensity is dependent on the rotational speed of the cellular wheel, the rotational speed of the cellular wheel is regulated in subsequent processes in order to adapt the conveying intensity to the requirement for feed material. To improve the metering accuracy with a greatly varying feed material supply, the distance of a pilot control point from the discharge point is determined in adaptation to the respective actual speed and / or load of the device.DE 10 2019 205 736 A1 discloses a metering device with a rotary feeder for metering coal dust. Within the housing of the metering device, a rotationally driven cell wheel with a plurality of cell wheel chambers is arranged, which are charged with coal dust via an inlet opening and, during the rotation of the cell wheel, reach the region of an outlet opening via which emptying thereof takes place. In the region of the rotary vane chambers, a compressed air line is provided, by means of which the coal dust is fluidized in the chambers and the flowability thereof is thereby improved. The pulverized coal should thus be able to be discharged earlier and more continuously from the metering device.Usually, the above-mentioned metering devices are distinguished by a delivery rate control range in a range of up to 1:5, at most up to 1:10, which is however not sufficient for certain processes. For example, in cement production, the ground and mixed raw materials are fired in rotary kilns at high temperatures to form cement clinkers. As a rule, a mix of coal dust and replacement fuels is used as the fuel, wherein the rotary kilns are preferably operated with maximum quantity of replacement fuels and coal dust is only metered in in a quantity necessary to maintain constant combustion. Since the firing rates of the replacement fuels are highly dependent on their type, charging furnaces with varying feed results in widely varying firing rates which must be compensated for with appropriate metering of pulverized coal. At the same time, the respective availability of the fuels up to a failure of the replacement fuels must be compensated for by suitable metering of coal dust. Only apparatuses with a large control range meet these requirements, wherein, above all at minimum conveying rates, charging with coal dust which is as free from pulsations as possible is important.SUMMARY OF THE INVENTIONAgainst this background, the object of the invention is to specify a device and a method for metering pourable feed material, in which the conveying strength can be regulated within wide limits, in particular also in the range of low conveying strengths.A further object of the invention is to avoid, as far as possible, pulsation of the material flow when metering the feed material, in particular at low conveying strengths.These objects are achieved by a device of the type described at the beginning, wherein the circumferential offset between a first cell of the first circular path and a further cell of the further circular path is formed in such a way that, at the beginning of the entry of the further cell into the region of the outlet opening, the partial cross section A teil of the first cell corresponds to the x*1 / n of the full cross section A voll of the first cell, wherein the factor x lies in a range between 0.6 and 1.4.These objects are furthermore achieved by a method of the type described at the beginning, in which, after the partial cross section A teil of a first cell of a first circular path has cleared by x*1 / n, the cross section of which another cell of a further circular path enters the region of the outlet opening, wherein the factor x lies in a range between 0.6 and 1.4.Advantageous further developments of the invention are evident from the dependent claims.The terms "cross section", "full cross section A voll" and "partial cross section A teil" used below are to be understood in each case in the sense of a cross-sectional area which extends perpendicularly to the axis of rotation of the cell wheel.The basic idea of the invention is to dose the feed material with a plurality of comparatively small cells on a number of n different circular paths of a cellular wheel, wherein the cells successively deliver the feed material to a conveying device. The invention has recognized the relationship between the relative position of the rotating cells with respect to the stationary outlet opening and the continuity of the material flow downstream of the cell wheel. It is important here that the cells of the different circular paths are arranged with a circumferential offset v with respect to one another, which in cooperation with the geometry of the outlet opening leads to a cell, preferably each cell leading in the direction of rotation, forming a partial cross section A teil in the region of intersection with the outlet opening, via which partial cross section emptying of the cell already takes place before a cell of another circular path immediately following it enters the region of the outlet opening. In the case of a number of n circular paths of the cell wheel, the offset v of the two cells entering the outlet opening immediately one after the other is such that the leading cell forms a partial cross section A teil of the size of the x*1 / n of its full cross section A voll with the outlet opening before the immediately following cell enters the region of the outlet opening and in turn begins to form a partial cross section A teil according to the invention. According to the invention, the factor x is in a range from 0.6 to 1.4, preferably in a range between 0.8 and 1.2.Compliance with these parameters leads to a homogenization of the material flow downstream of the cell wheel, i.e. fluctuations in the quantity of the feed material are minimized, which allows metering with high precision. Even in the region of low delivery rates, a substantially constant discharge of material is maintained, which enables a pulsation-free and at the same time exact metering and delivery. Devices and methods according to the invention are therefore distinguished by a comparatively large adjustment range of the conveying intensity, which considerably extends their possible uses. Thus, with methods according to the invention, adjustment ranges of the conveying intensity of, for example, up to 1:100 are achieved. In this case, a high metering quality is ensured, in particular also in the lower adjustment range with low delivery rates, which is a prerequisite for use in numerous subsequent processes such as, for example, fuel metering.These advantages are already clearly evident if the overlap of a leading cell with the outlet opening when the immediately following cell enters the region of the outlet opening is in a range between 0.6*1 / n and 1.4*1 / n. By further delimiting the overlap region, for example, to a range between 0.8*1 / n and 1.2*1 / n, a further increase of the described advantages and effects can be achieved. The best results are achieved according to the invention with an overlap of 1 / n.In implementing the idea of metering the feed material by means of many cells which are smaller for this purpose, it is provided in an advantageous development of the invention to design the cell wheel as slender as possible with a comparatively large diameter in relation to the axial thickness of the cell wheel. A large diameter allows both in the radial direction and in the circumferential direction the arrangement of a relatively large number of cells, the volumes of which available for metering are limited, however, on account of the relatively small thickness of the cellular wheel. In this embodiment of the invention, the material discharge is composed of a large number of small individual quantities released in a time-shifted manner, which results in a significantly more constant material flow. In this sense, a ratio of the axial thickness of the cellular wheel to its diameter in a range of less than 1:3, preferably less than 1:4 and most preferably less than 1:5 has proven to be particularly efficient.According to a preferred embodiment of the invention, the cellular wheel has three to five circular paths, preferably four. Since the outlet opening extends over all circular paths in the radial direction, in this embodiment three to five, preferably four, cells successively enter the region of the outlet opening and are emptied before the cycle repeats with the following cells of the circular paths. By distributing the feed to be metered over a plurality of cells which deliver the feed at uniform intervals, the continuity of the material flow is improved and the quality of the metering is increased.It has proven to be advantageous if all circular paths of the cell wheel have the same number of cells. In this way, exactly one cell following on another circular path can be assigned to each preceding cell over all circular paths, which is conducive to constant material discharge. In this sense, a number of cells of a circular path in a range between 24 and 32 has proven to be particularly advantageous, in particular 28.Preferably, the cells of a circular path are arranged at a uniform circumferential distance from one another with the advantage that the emptying of the individual cells of a circular path takes place at a uniform time distance and can thus be better matched to the emptying of the cells of other circular paths.In an advantageous development of the invention, the full cross section A voll of all cells is of the same size independently of the circular path on which they are arranged. Since all cells have an identical height in the axial direction, all cells have the same volume. Thus, all cells emit the same amount of feed material during the metering, which additionally contributes to a homogenization of the material flow. Full cross sections A voll suitable in this sense have cross-sectional areas in a range from 15 cm 2 to 70 cm 2, preferably from 30 cm 2 to 40 cm 2.With regard to the geometry of the cells of different circular paths, it has proven advantageous if the ratio of radial length r to tangential width u of the individual circular paths is different, with the proviso that the ratio r / u of a radially further inner circular path is greater than the ratio r / u of a circular path lying radially further outward in comparison therewith. The ratio r / u of the individual circular paths thus becomes smaller from radially inside to radially outside. This is based on the finding that the cells of circular paths located radially further inside have a lower circumferential speed than the cells of circular paths located radially further outside during rotation of the cell wheel. This results in a different opening behavior of the cells of different circular paths, which is compensated for with this measure to achieve a constant discharge of material.In an advantageous development of this embodiment, the ratio of radial length r to the tangential width u of the cells of a radially inner circular path is greater than 1 and / or the ratio of radial length r to the tangential width u of the cells of a radially outer circular path is less than 1.In addition, it has proven to be an advantage that the implementation of the invention is not limited to specific cross-sectional shapes of the outlet opening, but can be used with any desired cross-sections. However, cross sections of the outlet opening are preferred in which the circumferential section that is teil to form the partial cross sections A runs convexly or radially. This is the case, for example, with an outlet opening in the form of a circle, oval, circular ring segment, trapezoid or with a kidney shape. These embodiments simplify, on account of known geometric sizes and relationships, the arrangement according to the invention of the cells on the individual circular paths with the respective necessary circumferential offset v.In order to effect the emptying of the cells of the cell wheel as directly as possible after the cells enter the region of the outlet opening, a device for supplying compressed air to the cell wheel is advantageously provided. The feed material is conveyed pneumatically from the cells into the outlet device.As a drive of a device according to the invention, a servomotor is preferred which enables continuous regulation of the cellular wheel even at low rotational speeds, which improves the dosing accuracy.Without being limited thereto, the invention is explained in more detail below with reference to an exemplary embodiment in the form of a rotary feeder, which is illustrated in the drawing, wherein further features and advantages of the invention become apparent. The cellular wheel lock has a cellular wheel with cells on four circular paths. The number n is thus 4.Brief Description of the DrawingsIt shows FIG. 1 is a vertical section through a device according to the invention, FIG. 2 shows a view of the underside of the cell wheel of the device shown in FIG. 1, FIG. 3 ashows a detail of the cell wheel shown in FIG. 2 on a larger scale in a first rotational angle position I relative to the outlet opening, FIG. 3 bshows a detail of the cell wheel illustrated in FIG. 2 on a larger scale in a second rotational angle position II with respect to the outlet opening, and FIG. 4 shows a diagram with the curves P 1 to P 4 of the partial cross sections A teil of the cells in relation to their full cross sections A voll as a function of the angle of rotation φ of the cell wheel.DESCRIPTION OF THE EMBODIMENTSFIG. 1 shows a vertical section of an apparatus 1 according to the invention in the form of a horizontal rotary feeder. The device 1 has a substantially cylindrical housing 2 which extends along an axis 3. The housing 2 comprises a base plate 4 arranged coaxially to the axis 3 and a cover plate 5 arranged at an axial distance parallel thereto, which cover plates are connected along their opposite edges by a circumferential wall 6 and thus enclose a cylindrical working space 7. Via an inlet opening 8 in the cover plate 5 and an outlet opening 9 in the base plate 4, the working space 7 is accessible from opposite sides of the housing 2.On the upper side of the cover plate 5, coaxially to the axis 3, a tubular material inlet 10 is fastened, to which the outlet hopper 11 of a storage container filled with feed material 12, such as coal dust, connects. At the bottom side of the base plate 4, the outlet opening 9 merges into a tubular material outlet 13 which delivers the metered feed material 12 to a conveying device, not shown in detail.In the present exemplary embodiment, the outlet opening 9 has a circular shape and is arranged eccentrically with respect to the axis 3 with a circumferential offset of preferably 180° with respect to the inlet opening 8. Other geometries of the outlet opening 9, such as, for example, rectangular shape, trapezoidal shape, oval shape, kidney shape or the shape of a circular ring section, are likewise within the scope of the invention.The base plate 4 has a circular opening 14 arranged centrally with respect to the axis 3, into which a cylindrical shaft bearing 15 aligned coaxially with respect to the axis 3 is inserted with one end thereof, while the other end thereof protrudes freely from the base plate 4. In the shaft bearing 15, a drive shaft 17 is rotatably mounted by means of roller bearings 16. The drive of the drive shaft 17 is effected with the aid of a servomotor 21, which is force-coupled via a gear 20 and a drive belt 19 to a belt pulley 18 seated on the drive shaft 17.The upper end of the drive shaft 17 facing the material inlet 10 is formed by a pin 22 which projects through an opening 24 concentrically arranged in the cover plate 5. Seated on the pin 22 in a rotationally fixed manner is a stirrer 25, which is arranged within the material inlet 10 and the radial stirrer spokes 26 of which circle in the material inlet 10 about the axis 3 during the rotation of the drive shaft 17.At the upper end of the drive shaft 17 there is also provided an annular flange 27 which extends around the outer periphery and serves for the rotationally fixed connection of a cellular wheel 28 which is seated coaxially on the drive shaft 17. For this purpose, the cellular wheel 28 has a hub body 29 with an annular collar 30 which projects radially still inwards and which rests on the annular flange 27 of the hollow shaft 17 and is screwed to the latter. The cellular wheel 28 fills the entire working space 7.In a merely schematic illustration, compressed air lines 36 integrated into the cover plate 5 are seen axially opposite the base plate 4, the individual outlets 37 of said compressed air lines opening into the working space 7 on the underside of the cover plate 5 in order to apply compressed air to the cell wheel 28 during emptying.The more detailed configuration of the cell wheel 28 is the subject matter of FIGS. 2, 3 aand 3 b. The cellular wheel 28 has an annular disk body 31 which is radially subdivided into four circular paths, namely a radially inner circular path 32.1, a radially semiinner circular path 32.2, a radially semiinner circular path 32.3 and a radially outer circular path 32.4, which concentrically surround the axis 3 on different radii. All circular paths 32.1 to 32.4 have an annular shape and are formed by cells 33, which are separated in the circumferential direction by narrow radial webs 34 and in the radial direction by narrow annular webs 35. Radial webs 34 and annular webs 35 thus represent the cell walls. Only the cells 33 of the radially outer circular path 32.4 are open to the outside and are bounded by the circumferential wall 6. The radial webs 34, which form the cell walls which are at the front in the direction of rotation 38, have a slope 23 which in each case originates from the upper side and underside of the cell wheel 28, with the result that the thickness of the radial webs 34 is at its greatest at half the height of the cells 33. Together with the base plate 4, cover plate 5 and circumferential wall 6, the cells 33 form chambers which are closed on all sides and which rotate about the axis 3 in the working space 7 during operation of the device 1. The direction of rotation is indicated in FIGS. 3 aand 3 bwith the arrow 38. The circumferential speed of the cellular wheel 28 is, for example, in a range of up to 1 m / s depending on the conveying intensity and can be throttled continuously until standstill.All circular paths 32.1 to 32.4 have an identical number of cells 33, and all cells 33 of one and the same circular path 32.1, 32.2, 32.3 or 32.4 are uniformly spaced apart in the circumferential direction. In this case, the cells 33 of different circular paths 32.1 to 32.4 are arranged with a circumferential offset v with respect to one another (FIGS. 3 a, 3 b).With regard to the geometric design of the cells 33, it applies that, with respect to a perpendicular plane to the axis 3, all cells 33 of all circular paths 32.1 to 32.4 have an identical axial height and an identical full cross section A voll so that the volume of all chambers formed by the cells 33 is also identical. Furthermore, all cells 33 of one and the same circular path 32.1, 32.2, 32.3 or 32.4 have an identical cross-sectional shape, which preferably corresponds to a circular ring segment. In contrast, the cross-sectional shapes of the cells 33 of different circular paths 32.1 to 32.4 differ from one another in that a cell 33 of a radially further inner circular path 32.1, 32.2 or 32.3 has a greater length r in the radial direction and a smaller mean width u in the circumferential direction compared to a cell 33 of a radially further outer circular path 32.2, 32.3 or 32.4. The ratio r / u of the cells 33 of adjacent circular paths 32.1 to 32.4 thus decreases from radially inside to outside. In the present exemplary embodiment, the ratio r / u of the cells 33 of the radially further inner circular path 32.1 and / or circular path 32.2 is greater than 1 and the ratio r / u of the cells 33 of the radially further outer circular path 32.3 and / or circular path 32.4 is less than 1.During operation of a device 1 according to the invention, the feedstock 12 reaches the inlet opening 8 in the cover plate 5 via the material inlet 10 due to gravity and flows there into the cells 33 of the cell wheel 28 which are open at the end face and which rotates in the direction of the arrow 38. The intersecting cross sections form a partial cross section A teil, which is variable as a function of the angle of rotation φ of the cellular wheel 28 and continuously increases from the entry of a cell 33 into the region of the outlet opening 9 until the full cross section A voll is reached. Emptying of the cellular wheel 28 takes place already via the partial cross section A teil even before the cell 33 with its full cross section A voll lies completely in the region of the outlet opening 9. This applies in particular at low rotational speeds of the cellular wheel 28.In the present exemplary embodiment, the arrangement of the cells 33 on the different circular paths 32.1 to 32.4 is selected such that the cells 33 successively entering the outlet cross section 9 are located on different circular paths 32.1 to 32.4 and are arranged with a circumferential offset v with respect to the cell walls leading in the rotational direction 38. If, for example, a cell 33 of the radially inner circular path 32.1 is assumed as the cell 33 entering the outlet opening 9 (see FIG. 3 b), it is next followed by a cell 33 of the radially half-outer circular path 32.3, followed by a cell 33 of the radially outer circular path 32.4, and finally by a cell 33 of the radially half-inner circular path 32.2 (see FIG. 3 a), before the sequence cycle begins again with the following cell 33 of the radially inner circular path 32.1.The circumferential offset v is selected such that a leading first cell 33 of a first circular path 32.1 to 32.4 is located, when a directly following further cell 33 of another circular path 32.1 to 32.4 enters, in a position in which the partial cross section A teil of the leading first cell 33 formed up to then corresponds to a quarter of its full cross section A voll.FIG. 3a shows the situation in which a filled cell 33 of the radially semiinner circular path 32.2 with the cross section A voll is about to enter the region of the outlet opening 9. In this first rotational angle position I of the cellular wheel 28, the first cell 33 of the radially outer circular path 32.4, which cell immediately precedes it in the rotational direction 38, is already located with a part of its full cross section A voll in the region of the outlet opening 9.During the continuous rotation, a continuously increasing partial cross section A teil of the cell 33 of the radially semiinner circular path 32.2 results, until in a second rotational angle position II of the cell wheel 28, the partial cross section A teil corresponds to a quarter of the full cross section A voll of the cell 33. This state of the second rotational angle position II is shown in FIG. 3 b, in which the immediately following cell 33 of the radially inner circular path 32.1 enters the region of the outlet opening 9.These processes are repeated with the leading cells 33 of the circular path 32.1 and immediately following cells 33 of the circular path 32.3 as well as the leading cells 33 of the circular path 32.3 and immediately following cells 33 of the circular path 32.4 before a new sequence cycle begins. In this way, a continuous stream of material is achieved downstream of the cell wheel 28.FIG. 4 shows the curves P 1 to P 4 of the partial cross sections A teil dependent on the angle of rotation φ in relation to the full cross sections A voll of the cells 33 of the individual circular paths 32.1 to 32.4 from entering the region of the outlet opening 9 to the complete overlap. The course P 1 represents the ratio of the cells 33 of the circular path 32.1, the course P 2 that of the cells 33 of the circular path 32.2, the course P 3 that of the cells 33 of the circular path 32.3 and the course P 4 that of the cells 33 of the circular path 32.4. The curves P 1 to P 4 show similar characteristics with a gradual increase when entering the region of the outlet opening 9, followed by a steeper, approximately linear increase in the middle region, before the curves P 1 to P 4 flatten again.The 1 / n line is entered parallel to the ordinate in the diagram, wherein in the present exemplary embodiment the value 1 / n corresponds to the value 0.25 on account of the four circular paths 32.1, 32.2, 32.3, 32.4 of the cell wheel 28.It can be seen that at the intersection of the course P 4 with the 1 / n line, the partial surface A teil has reached the cell 33 on the radially outer circular path 32.4 a quarter of its full cross section A voll. This corresponds to a first rotational angle position I at a rotational angle φ of approximately 10°, which represents the beginning of the course P 2 i.e. marks the entry of the cell 33 of the radially semiinner circular path 32.2 into the region of the outlet opening 9 and thus corresponds to the state shown in FIG. 3 a.During the continuous rotation of the cellular wheel 28, the partial cross section A teil of the cell 33 of the radially semiinner circular path 32.2 increases continuously until, when the second rotational angle position II is reached at a rotational angle φ of approximately 15°, the profile P 2 intersects the 1 / n line, the partial cross section A teil thus corresponds to a quarter of the full cross section A voll. In this second rotational angle position II, the course P 1, begins, which shows that the immediately following cell 33 of the inner circular path 32.1 reaches the region of the outlet opening 9 and, for its part, forms a partial cross section A teil.These processes are repeated in the third rotational angle position III with the cell 33 of the radially inner circular path 32.1 as leading cell 33 and the immediately following cell 33 of the radially semi-outer circular path 32.3 and in the fourth rotational angle position IV with the cell 33 of the radially semi-outer circular path 32.3 as leading cell 33 and the immediately following cell 33 of the radially outer circular path 32.4 before a new sequence cycle begins. In this way, a uniform pulsation-free material flow is achieved in the material outlet 13 of the device 1.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedEP 1 012 545 B1

[0004] DE 10 2019 205 736 A1

[0005]

Claims

Device for metering pourable feed material (12), having a housing (2) extending along an axis (3), comprising a base plate (4), a cover plate (5) arranged at an axial distance therefrom, and a circumferential wall (6) connecting the base plate (4) and cover plate (5), which circumferential wall enclose a working space (7) in which a cell wheel (28) rotating about the axis (3) is arranged, having a multiplicity of cells (33) which are arranged concentrically about the axis (3) on a number of n circular paths (32.1, 32.2, 32.3, 32.4), wherein the cells (33) of a first circular path (32.4) are arranged with a circumferential offset v with respect to the cells (33) of a further circular path (32.2), and wherein the upper sides of the cells (33) facing the lid plate (5) and the lower sides of the cells (33) facing the bottom plate (4) are open and form chambers rotating about the axis (3) with the lid plate (5) and bottom plate (4), and wherein the housing (2) has an inlet opening (8) via which the feedstock (12) can be supplied to the cells (33) of the cellular wheel (28), and an outlet opening (9) via which the cells (33) of the cellular wheel (28) can be emptied, wherein the filled cells (33) enter the region of the outlet opening (9) in the course of the rotation of the cell wheel (28) and each cell (33) with its cell walls and the outlet opening (9) forms a respective partial cross section A teil which is dependent on the angle of rotation and which occurs in the course of the entry, characterized in that the circumferential offset v between a first cell (33) of the first circular path (32.4) which leads in the direction of rotation (38) and a further cell (33) of the further circular path (32.2) which directly follows in the direction of rotation is designed in such a way that, at the beginning of the entry of the further cell (33) into the region of the outlet opening (9), the partial cross section Apart of the first cell (33) corresponds to the x*1 / n of the full cross section A voll of the first cell (33), where x is in a range from 0.6 to 1.4.Device according to claim 1, characterised in that x lies in a range between 0.8 and 1.2, preferably amounts to 1.Device according to claim 1 or 2, characterised in that the cellular wheel (28) has three to five circular paths (32.1, 32.2, 32.3, 32.4) on which the cells (33) are arranged, preferably four circular paths (32.1, 32.2, 32.3, 32.4).Device according to one of Claims 1 to 3, characterized in that all circular paths (32.1, 32.2, 32.3, 32.4) have an identical number of cells (33), preferably 24 cells to 32 cells, in particular 28 cells.Device according to one of Claims 1 to 4, characterized in that the cells (33) of a circular path (32.1, 32.2, 32.3, 32.4) are arranged at a uniform circumferential spacing from one another.Device according to one of Claims 1 to 5, characterized in that the cells (33) of all circular paths (32.1, 32.2, 32.3, 32.4) have an equally large full cross section A voll.Device according to any one of claims 1 to 6, characterised in that the full cross-section A voll of the cells (33) is in a range from 15 cm 2 to 70 cm 2 preferably in a range from 30 cm 2 to 40 cm 2.Device according to one of Claims 1 to 7, characterized in that the wall of a cell (33) which leads in the direction of rotation (38) has, at least over part of its axial height, an inclination (22) with respect to the upper side and / or lower side of the cell wheel (28).Device according to one of Claims 1 to 8, characterized in that the ratio of the radial length r to the tangential width u of the cells (33) of the individual circular paths (32.1, 32.2, 32.3, 32.4) is different, wherein the ratio r / u of a circular path (32.1, 32.2, 32.3) located radially further inside is greater than the ratio r / u of a circular path (32.2, 32.3, 32.4) located further outside in comparison therewith.Device according to one of Claims 1 to 9, characterized in that the ratio of the radial length r to the tangential width u of the cells (33) of a radially inner circular path (32.1, 32.2, 32.3) is greater than 1 and / or the ratio of the radial length r to the tangential width u of the cells (33) of a radially outer circular path (32.2, 32.3, 32.4) is less than 1.Device according to one of Claims 1 to 10, characterized in that the ratio of the axial thickness of the cellular wheel (28) to its diameter is in a range of less than 1:3, preferably less than 1:4, most preferably less than 1:5.Device according to one of Claims 1 to 11, characterized in that the outlet opening (9) is formed convexly or radially in the circumferential section forming the partial cross sections A teil.Device according to one of Claims 1 to 12, characterized in that the outlet opening (9) is of circular, oval, sector-shaped, rectangular or trapezoidal configuration.Device according to one of Claims 1 to 13, characterized in that the device (1) has a servomotor (21) for driving the cellular wheel (28).Device according to one of Claims 1 to 14, characterized bya device for supplying compressed air to the cellular wheel (28), having compressed air outlets (37) which can be acted upon by compressed air via compressed air lines (36), the compressed air outlets (37) being aligned axially opposite the outlet opening (9) and on the circular paths (32.1, 32.2, 32.3, 32.4).Method for metering pourable feed material by means of a cellular wheel sluice having a housing (2) and a cellular wheel (28) which rotates within the housing (2) about an axis (3) and which has a multiplicity of cells (33) which are arranged on a number of n circular paths (32.1, 32.2, 32.3, 32.4) concentrically about the axis (3) and to which the feed material (12) is fed via an inlet opening (8) in the housing (2) and which are emptied via an outlet opening (9) in the housing (2), wherein the filled cells (33) enter the region of the outlet opening (9) by rotating the cellular wheel (28) and each cell (33) with its cell walls and the outlet opening (9) forms a partial cross section A teil which is dependent on the angle of rotation arising during the entry, characterized in that a first cell (33) of a first circular path (31.4) forms a partial cross section A teil which corresponds to the x*1 / n of its full cross section A voll before a further cell (33) of a further circular path (32.2) enters the region of the outlet opening (9), wherein x lies in a range between 0.6 and 1.4.

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