Feed device and rolling mill

Abstract

A feed device (1) for a rolling mill for food processing has a collecting space (12) into which material to be processed can be fed via an inlet (11). A feed roller (14) is used to convey the material to be processed (12) that is present in the collecting space, away from the collecting space. For this purpose, it is arranged on the underside of the collecting space (12) and is rotatable about an axis. The feed device has a first conveyor device (17) above the feed roller for conveying the material to be processed in the collecting space, in the axial direction. It is characterised by a second conveyor device (18) for conveying material to be processed conveyed by the first conveyor device, in a direction different from the conveying direction of the first conveying device. This ensures a particularly uniform distribution of the material to be processed along the axis of the feed roller (14).

Description

[0001] FEEDING DEVICE AND WAUZMACHINE

[0002] The invention relates to a feeding device for a rolling mill for food processing, for example a roller mill or a flaking mill, and to a rolling mill with a feeding device.

[0003] State-of-the-art roller mills often have a centrally located inlet for the material to be ground. The material to be ground is accumulated in a collection chamber and from there, conveyed by a feed roller, into the grinding chamber, where it is crushed between grinding rollers. The axis of the feed roller is generally parallel to the axes of the grinding rollers, and the collection chamber extends longitudinally over the entire length of the feed roller. According to the state of the art, the collected material to be ground is distributed over the length of the feed roller, for example, by gravity, by ensuring that the collection chamber is large enough to form a cone whose width corresponds to the length of the feed roller. Technical developments mean that roller mills are being manufactured with increasingly longer grinding rollers and, consequently, also with increasingly longer feed rollers.Therefore, the inlet must be constructed increasingly higher to ensure a sufficiently wide receptacle. However, this has its limits, which is why gravimetric distribution is no longer sufficient beyond a certain roller length - depending on the nature of the material to be ground, which defines the angle of the receptacle. State-of-the-art technology therefore also includes a solution of actively conveying the material to the outside using a conveyor shaft above the feed roller. The conveyor shaft is driven by the drive of the feed roller. To accommodate different material properties, the paddles of such conveyor shafts designed as paddle shafts have an adjustable paddle angle. This solution also makes the feeding device suitable for larger roller mills with grinding rollers more than one meter long and / or for less free-flowing products.However, this solution has the disadvantage that the paddles can only be adjusted when the collection chamber is empty and operation is interrupted. Furthermore, in practice, it is very difficult to find the optimal setting. Therefore, one often has to accept that the distribution along the length of the feed roller is not entirely even, with the feed roller conveying less ground material at its outer ends, or that ground material builds up at the ends of the conveyor shaft, which over time carries the risk of machine defects or permanent, unhygienic ground material buildup. Furthermore, if different products with different flow properties are ground, the feeding device would have to be readjusted again and again. This is rarely done in practice, which is why the feeding device is often operated in a non-optimized mode, with an uneven distribution of the ground material along the length of the rollers.A further disadvantage of the state-of-the-art solutions is that paddle shafts with adjustable paddles are potentially unhygienic because they have open threads and screws in the collection chamber, i.e. in direct contact with the ground material.

[0004] EP 3 572 152 therefore proposes a feeding device in which the ground material inlet and a first fill level sensor are mounted at one end of the feed roller and the conveyor shaft, and a second fill level sensor at the other end of the feed roller and the conveyor shaft. According to this solution, the speed of the conveyor shaft is designed to be adjustable independently of that of the feed roller. This solution is intended to ensure that the feed roller is always supplied with ground material along its entire length. However, it requires relatively complex sensors and a rather complicated control system and is sensitively dependent on the flawless functioning of the fill level sensors; in the event of malfunctions, accumulated ground material must leave the collection chamber at the other end through the feed gap. When clearing a malfunction, there is a risk that no product will be discharged for a short time in certain sections.Furthermore, a malfunction can cause the material to be ground to compress at the end of the conveyor shaft. Due to the lateral material inlet, the feed device also requires modifications to existing grain mills during installation, as these are generally designed for roller mills with a centrally located inlet.

[0005] Another issue related to roller mills and their feed devices is aspiration. The collection chamber is generally under overpressure, as air flows in along with the ground material. If this pressure is not reduced, it will be expelled from the collection chamber; moreover, air can flow from the collection chamber into the feed gap. For this reason, and also to reduce dust and moisture, it was proposed to extract air from the collection chamber via a dedicated connection. According to an initial approach (external aspiration), this is achieved by connecting a separate air duct with its own fan. This creates additional overhead and entails greater installation costs (pipe construction).

[0006] Another option involves connecting an extraction point in the collection chamber to the pneumatic conveying line via a suitable pipe. The pneumatic conveying line, which is often already present, serves to convey the ground material away from the grinding gap and collection through a hopper (tri-meile). The connection to the pneumatic conveying line eliminates the need for a separate aspiration system or, if one already exists for other milling machines, allows for a smaller dimensioning of this aspiration system and avoids the need for additional pipe construction. However, this requires an additional pipe that is difficult to access for cleaning and maintenance, and is also relatively complex.

[0007] Another approach (internal aspiration) proposed installing a correspondingly shorter pipe between a lateral location in the collection chamber above the feed roller and the grinding chamber to allow pressure equalization. With this solution, the airflow can draw fine particles into the pipe, as the airflow is directed past the level of the ground material, and the pipe is designed to be positioned close to this level. This can lead to deposits on the pipe and even clogging.

[0008] It is an object of the present invention to provide a feeding device for rolling mills for food processing, as well as such a rolling mill, in particular a roller mill, which overcomes the disadvantages of the prior art. A further object is to provide a uniform, easily controllable feed of processed material into the processing chamber (e.g., grinding chamber) with the processing rollers (e.g., grinding rollers), whereby the feed should be reliable despite varying properties of the processed material. Another object is to provide a solution to the aspiration problem.

[0009] These objects are achieved by the invention as defined in the patent claims.

[0010] According to a first aspect of the invention, a feeding device for a rolling mill for food processing is provided. This device has a collecting chamber into which a processing material can be fed via an inlet. A feed roller serves to convey processing material present in the collecting chamber away from the collecting chamber. For this purpose, it is arranged on the underside of the collecting chamber and rotatable about an axis. Through its rotation, it entrains the processing material and conveys it, in particular through a feeding gap, the width of which can be adjusted in a conventional manner, for example by means of an adjustable slide. The feeding device has a (first) conveying device above the feed roller for conveying the processing material in the collecting chamber in the axial direction ('axial' refers to the axis of the feed roller), towards at least one end.It is characterized by a second conveyor device for conveying processed material conveyed by the first conveyor device in a different direction, away from the end side.

[0011] The second conveying device can be designed, in particular, to convey the material to be processed conveyed by the first conveying device in an axial direction opposite to the axial direction (in which the first conveying device conveys).

[0012] In this text, "processed product" generally refers to a food product, especially a grain product, that is to be processed in a rolling mill, which is in bulk. If the rolling mill is a roller mill, the processed product is a ground product. If the rolling mill is a flaking mill, the processed product is grain kernels, groats, or meal that are to be blocked.

[0013] The second conveyor is therefore arranged in such a way that it conveys the processed material away from the end side, within the collection chamber. Material cannot accumulate at the end side; instead, any excess material conveyed to the end side returns to an area where it can be captured by the feed roller or the first conveyor shaft.

[0014] The second conveyor will, in particular, convey the processed material conveyed by the first conveyor back in the direction from which it came. If the feed device has a central inlet into the collection chamber, the first conveyor will convey the material axially toward the sides, away from the center and outward. The second conveyor will then convey portions of the processed material conveyed outward back to the inside, depending on the set conveying speed of the first conveyor.

[0015] In the case of a non-central inlet at the side of the collecting chamber, the first conveyor device conveys the processing material away from the side with the inlet towards the other end, and the second conveyor device conveys, for example - also depending on the set conveying speed of the first conveyor device - processing material back towards the side with the inlet.

[0016] It is also possible for the second conveyor to convey the material upwards from the end sides or from the end side, from where it falls back down past the second conveyor due to the effect of gravity, with at least a portion of the upwardly conveyed material also being moved back in the direction from which it came. This variant also prevents the material from accumulating and compressing at the end sides or the end side, and also provides a certain amount of return transport in the direction from which the material came. The second conveyor solves the problem described above.The first conveyor can be operated at a conveying capacity that is always sufficient to reliably convey the processed material to the outer ends (with a central inlet) or the opposite end (with a lateral inlet), even with changing properties of the processed material, and regardless of the presence of air pockets or the like. The conveying speed can, for example, depend solely on the rotational speed of the feed roller, which inevitably arises if—which may be an option—the first conveyor is driven by the same drive as the feed roller. The first conveyor can therefore, in particular, be operated with a conveying capacity that is slightly too high on average, thus conveying slightly more processed material than actually necessary.The second conveyor then ensures that any excess material conveyed does not accumulate and compact at the end, but is conveyed back and eventually distributed along the axis of the feed roller. This approach therefore makes distribution along the axis of the feed roller very robust and reliable.

[0017] A further advantage of the approach according to the first aspect of the invention is that the feed device can be operated with pumping and recirculating fluid for an extended period of time upon startup until the collection chamber is optimally filled and mixed. This is not possible with feed devices according to the prior art.

[0018] The second conveyor device is arranged in such a way that it conveys in particular any excess portions of the processing material. The second conveyor device can, for example, be arranged above the first conveyor device, i.e. directly vertically above or with a horizontally offset, for example parallel, conveyor axis. Depending on the geometry of the collection space, the second conveyor device can also be located in a different position, e.g. next to the first conveyor device. The first conveyor device can, in particular, be designed as a conveyor shaft. This is particularly well suited for use in an environment partially filled with processing material, since both ends can be easily sealed from the outside and the shaft as a whole does not contain any areas that must not be covered by the processing material. Such a conveyor shaft generally has a shaft core (“soul”) with helical conveyor structures on it.These can be formed by discrete paddles or, alternatively, by a continuous screw thread. In the latter case, the shaft can also be designed without a shaft core, a so-called "shaftless" screw conveyor.

[0019] The second conveyor device can also be a conveyor shaft, arranged horizontally, for example, with its axis parallel to the axis of the feed roller. This offers the same advantages as for the first conveyor shaft. The second conveyor device can also be formed by two separate conveyor shafts at each end, with a centrally arranged inlet. Particularly in this case, the conveyor axes of the second conveyor device can also be positioned at an angle to the axial direction, for example, diagonally or even vertically upwards.

[0020] Alternative conveying devices include, for example, moving belts or rollers, for example belts or rollers running at the front and / or rear along the edge of the collection space with conveying structures that extend inwards into the collection space. Other alternative conveying devices are also not excluded, for example, as an option for the second conveying device, the use of compressed air, by which the material to be processed is blown back inwards from the end sides or the end side above the first conveying device. With a central inlet, at least the second conveying device can be free of conveying structures in a central area below the inlet. On the one hand, such conveying structures are not actually necessary in the central area due to the dynamics present in the collection space, and on the other hand, this prevents undesired compaction of material portions conveyed in the opposite direction in the middle.

[0021] It is also possible for the second conveyor device – e.g., if it is designed as a horizontal (second) conveyor shaft – to be equipped with mixing structures in the area below the inlet, which mechanically process the material that comes into contact with it without systematically conveying it in one direction or the other. This further enhances one advantage of the inventive approach – especially with a "narrow" inlet as discussed in this text. The combination of a – e.g., a high-performance – first conveyor device with the second conveyor device can effectively prevent segregation when different material components are fed through different inlet nozzles. The additional mixing structures further enhance this positive effect.

[0022] Such mixed structures can, in particular, protrude radially outward from the shaft core and protrude from it. They can be formed, for example, by radially extending rods or by mixed strips – strips or plates extending parallel to the axis.

[0023] Particularly if the second conveyor device is a horizontal (second) conveyor shaft, it may be sufficient if the structures for conveying away from the end face(s) on the second conveyor shaft—e.g., paddles or a continuous screw thread—are only present near the end face(s). This leaves sufficient space for such mixing structures in a central area between the end faces.

[0024] Mixing structures of the type described effectively counteract bridging, especially in the case of poorly flowing and / or sticky material, further mix the inlet product, ensure a smaller angle of repose, and have an overall positive influence on product flow by preventing zones of stagnant product. Especially when designed as mixing bars, they also result in somewhat higher power consumption, which is why they can be available as an option and can be reversibly attached to the second conveyor shaft, allowing them to be removed as needed, depending on the material to be ground.

[0025] In addition to or as an alternative to the mixing structures on the second conveyor, mixing structures on the first conveyor are also an option. These can also be arranged below the inlet.

[0026] If the conveying devices are designed as conveyor shafts with a shaft core, the conveying structures—e.g., paddles—can be firmly connected to the shaft core, e.g., welded, in contrast to prior art solutions. This results from the fact that, thanks to the approach according to the first aspect of the invention, mechanical adjustment of the conveying properties is unnecessary. The hygiene problems described above with open threads and screws in the collecting chamber can therefore be elegantly solved.

[0027] In one group of embodiments, at least the first conveyor device has its own conveyor drive, independent of the feed roller drive. Unlike prior art conveyor shafts, which are driven by a belt drive permanently connected to the feed roller drive, the conveying speed of the conveyor device(s) can thus be adjusted independently of the feed roller, even during operation.

[0028] The feeding device can therefore be equipped in particular to enable the conveying capacity to be adjusted by the first conveying device and, for example, also by the second conveying device without emptying the collecting space.

[0029] An independent drive, for example, has its own electric motor that is separate from the electric motor of the feed roller drive.

[0030] The independent conveyor drive may comprise a single electric motor that drives the first conveyor and, if applicable, also the second conveyor, e.g., via belts, gears, or other elements. It may also comprise one electric motor each for the first and second conveyors.

[0031] Particularly advantageous is the feature of the independent conveyor drive in combination with the optional feature of the fixed connection between the conveyor shaft core and the conveyor structures.

[0032] In one group of embodiments, the feed device is of the "narrow inlet" type, meaning that the collecting space is designed in an upper region like a chamber with a surrounding wall, open downwards toward the conveyors. The width (the axial dimension) is significantly smaller than the axial length of the feed roller and conveyors. Unless expressly stated otherwise, the "axial length" of the feed roller and conveyors always refers to the dimension inside the collecting space, excluding the portions of the roller or shafts (or other means) that penetrate the boundaries of the collecting space and serve as bearings and drive attachments.

[0033] In this text, the chamber-like area – in some embodiments it can be essentially box-shaped, with a rectangular floor plan – is referred to as the "upper collecting chamber section." The area with the conveyor device(s), which extends downwards to the feed roller and whose width corresponds to the length of the feed roller and the conveyor device(s), is referred to accordingly as the "lower collecting chamber section." The lower collecting chamber section adjoins the upper collecting chamber section at the bottom and, in addition to a front and rear boundary (wall and / or door, each with a window if necessary) and lateral boundaries, also has an upper boundary to the side of the upper collecting chamber section. This upper boundary can be essentially horizontal or it can be slightly inclined to the horizontal, e.g., at an angle of inclination of no more than 10°, no more than 7°, or no more than 5°.

[0034] Embodiments of this type have, among other things, the advantage that, compared to feeding devices with a collecting chamber that is wide right up to the top, a simpler and better control of the filling quantity in the collecting chamber is possible. Furthermore, the mixing of different processing materials is improved compared to feeding devices with a wide bulk material cone. However, the controllability of the filling level and the reliable transport of the processing material along the entire length of the feed roller are more demanding than with a wide collecting chamber, which is why the inventive procedure, especially with independent drive of the conveyor devices, is particularly well suited for such embodiments. The maximum width of the upper part of the collecting chamber (width, ieThe axial expansion of the internal volume is determined by the space typically available in grain mills, as well as by the requirement discussed below that the collecting chamber should be sealed at the bottom by the processed material during normal operation to ensure easy control of operation. The width – measured at the widest point of the upper collecting chamber section – can be, for example, a maximum of 50 cm, a maximum of 45 cm, or a maximum of 40 cm. It will generally be less than half the axial length of the feed roller.

[0035] The surrounding wall of the upper part of the collecting chamber can be vertical or at least partially slightly inclined to the vertical, for example with a maximum angle of inclination of 10°, 7° or 5°.

[0036] According to a second aspect of the present invention, which can be combined particularly well with the first aspect, a rolling mill, for example a roller mill, with a feed device of this type with an upper partial collection chamber and a lower partial collection chamber has at least one aspiration channel between the upper partial collection chamber and the processing chamber with the processing rollers. The aspiration channel is a gas-carrying line that can have a round, rectangular, or otherwise shaped cross-section, which does not have to be constant along the channel. In particular, one or more of the aspiration channels can be guided along the circumferential wall of the upper partial collection chamber and from there lead further down into the processing chamber, for example along a rear wall of the lower partial collection chamber.

[0037] In some embodiments, the at least one aspiration channel can end, in particular, above the pair of processing rollers. A solution with an aspiration channel connecting the upper collecting chamber section with the processing chamber above the processing rollers can be particularly advantageous: if the aspiration channel ended below the pair of processing rollers, the pressure resistance would be too high. If the aspiration channel began below the upper collecting chamber section, there is a risk of clogging.

[0038] The aspiration channel ensures that, during operation, air is constantly drawn from the inlet and the upper collecting chamber, where there is positive pressure, to the processing chamber, where there is negative pressure due to the suction and pneumatic conveying of the material to be processed. Internal aspiration thus takes place. By connecting the upper collecting chamber to the processing chamber, firstly, clogging of the aspiration channel can be very effectively prevented. Secondly, during operation, it is always ensured that no significant amount of air, and the fine material entrained with it, can flow along any path past the feed roller from the collecting chamber into the processing chamber.

[0039] The approach according to the second aspect of the invention also allows, under certain circumstances, the system to be sealed off with closed doors (e.g., the grinding chamber door; possibly, the door to the collection chamber). This also prevents uncontrolled moisture or spores, etc., from entering the area containing the processed material.

[0040] The rolling mill according to the second aspect is operated in particular such that the material to be processed always seals the upper collecting chamber from below, i.e., during normal operation, the material to be processed always occupies the entire cross-sectional area, at least at the bottom of the upper collecting chamber. Therefore, no significant amount of air can flow through the feed gap or through any leaks, e.g., on the sides, past the slide from the collecting chamber into the processing chamber and uncontrollably entrain the material to be processed. The at least one aspiration channel according to the second aspect of the invention takes this circumstance into account without incurring the disadvantages of external aspiration.

[0041] As is known per se—and optionally in all aspects of the present invention—the rolling mill's feed device can have a fill level monitor. The fill level determined by this—i.e., the level of the material to be processed in the collection chamber—can be incorporated into the control system to regulate the rotational speed of the feed roller and / or the conveying capacity of the conveying device(s). Additionally or alternatively, the fill level can also be used to control the quantity of material fed in, for example, via an inlet slide, an inlet flap, or another metering device.

[0042] According to a further, third aspect of the present invention, which can be particularly well combined with the first and / or second aspects, a feed device with a narrow inlet, i.e., with an upper collecting chamber with a peripheral wall and a lower collecting chamber with at least one conveyor (e.g., with two conveyors if the feed device also corresponds to the first aspect), has a viewing window that is not only present on the peripheral wall of the upper collecting chamber, but also extends downward into a cover of the lower collecting chamber. The viewing window has a width that is greater than the width of the upper collecting chamber.

[0043] The viewing window can extend axially close to the end sides of the lower collecting chamber. "Close to the end sides" in this context means that the ends of the conveyor device(s) extending through the lower collecting chamber are clearly visible through the viewing window. This could mean, for example, that the viewing window extends to the end sides on both sides or ends laterally at a distance of no more than approximately 10 cm from the end sides.

[0044] The viewing window can be continuous or divided. However, any division should not prevent all areas of the collection space from being visible, for example, up to the lower edge of the viewing window.

[0045] The viewing window, which, in contrast to the state of the art, not only provides visibility into the narrow area below the inlet (the upper part of the collection chamber), but also into the area with the conveyor system(s). This allows a visual assessment of the product distribution, product quality, and product mixing in the feeding device. As the viewing window extends from the upper part of the collection chamber to the lower part of the collection chamber, it allows a good assessment of the product flow through the feeding device. Any malfunctions, contamination, mold growth, etc. can also be viewed through the viewing window without having to interrupt operation or open the collection chamber. The viewing window can be hinged, allowing easy access to the collection chamber in the event that a malfunction, contamination, incipient mold growth, or similar is detected.

[0046] According to all aspects of the present invention, the rolling mill in the form of a roller mill can be designed as a multiple roller mill, with a plurality of pairs of grinding rollers, wherein the two pairs can be arranged one behind the other and thus at least approximately at the same height. In embodiments of the second and / or third aspect of the invention and generally in embodiments with a "narrow" inlet according to the definition used here, the roller mill can be designed such that the upper collecting chamber part is free of transport pipes leading through it. Any transport pipes present can be guided between the pairs of grinding rollers and between the feed rollers assigned to them and conveyor devices to the side of the upper collecting chamber part (which can be divided into two compartments, one for the front and one for the rear pair of grinding rollers). Such an arrangement is suitable for typical transport pipe diameters of, for example, approx.90-100 mm is also possible for the shortest common roller length of 1000 mm and for a total of up to four transport pipes arranged side by side through the roller mill, if the width of the upper part of the collecting chamber, including any aspiration channels running along its side, according to the second aspect is not more than approximately 55 cm, which is very compatible with the dimensions for the width of the upper part of the collecting chamber discussed above.

[0047] Embodiments of the invention are described below with reference to drawings. In the drawings, like reference numerals designate like or similar elements. The drawings are all schematic and not to scale. They show partially corresponding elements in different sizes from figure to figure. They show:

[0048] Fig. 1 : a representation of a feeding device;

[0049] Fig. 2 is a cross-sectional view of the feeding device of Fig. 1;

[0050] Fig. 3 is a diagram of an alternative supply device;

[0051] Fig. 4 the feeding device according to Fig. 3, together with transport pipes and with the fill level of the material to be processed indicated;

[0052] Fig. 5 shows a diagram of the control system; Fig. 6 shows a roller mill with an aspiration channel;

[0053] Fig. 7 is a top view of a double roller mill with a narrow inlet;

[0054] Fig. 8 shows a structure with conveyor devices with additional mixing structures;

[0055] Fig. 9-17 alternative possibilities for the design of the second conveyor device;

[0056] Fig. 18 is a cross-sectional view of an alternative embodiment of the feed device, analogous to Fig. 2; and

[0057] Fig. 19 schematically shows a first and second conveyor device with mixing bars.

[0058] Figures 1 and 2 show a feeding device 1 according to a first embodiment. The feeding device has an inlet 11 (shown only schematically in Fig. 1) on the top side and a collecting chamber 12 formed by a housing 2. The collecting chamber 12 is closed off at the bottom by a feed roller 14, which cooperates with an adjustable slide 15 to convey the material to be processed in the collecting chamber through a feed slot 16, so that it reaches the processing chamber (grinding chamber), where it is comminuted between grinding rollers.

[0059] The inlet 11 is located centrally (in relation to axial directions) above the feed roller 14 and the conveyor shafts 17, 18, which will be described in more detail below. As is known per se, the inlet can have one or more nozzles to which lines containing the fed-in processing material can be coupled. Due to the central arrangement of the inlet, the processing material must be distributed outwards in an axial direction for even distribution in the grinding gap (not shown in Figs. 1 and 2). To a certain extent, this is achieved by the accumulation of a cone of processing material beneath the inlet 11. However, this is generally not sufficient, which is why the processing material is actively conveyed in the axial direction for better axial distribution.

[0060] For this purpose, the feed device has a first conveying device, namely a first conveying shaft 17 for conveying the material to be processed in an axial outward direction, i.e., from a central region 31 below the inlet in two opposite directions, as indicated by the double arrows. For this purpose, paddles 19—or other conveying structures, e.g., structures that run helically at least in some areas—are oriented oppositely in two outer regions, i.e., arranged in a mirror image.

[0061] The feeding device also has a second conveying device, namely a second conveyor shaft 18 for conveying the material to be processed in the opposite axial direction, i.e. back inwards. The second conveyor shaft 18 is arranged above the first conveyor shaft so that it mainly collects portions of the material to be processed which would otherwise accumulate at the ends of the first conveyor shaft 17, i.e. axially outwards. In the example shown, the second conveyor shaft 18 is arranged above the first conveyor shaft 17, but is also slightly offset horizontally, namely towards the rear (see Fig. 2). Such a slightly offset arrangement has the advantage that the vertical distance between the conveyor shafts can be somewhat smaller than if the two conveyor shafts were arranged directly vertically one above the other.A reduced vertical distance, which, for example, is slightly smaller than the sum of the radii of the paddles 19, can be advantageous, as it can particularly effectively prevent lateral accumulation of the material to be processed. To ensure that the material to be processed is conveyed by the second conveyor shaft 18 in the opposite axial direction to that of the first conveyor shaft, the conveying structures (paddles 19), as indicated in Fig. 1, can be mounted in reverse, i.e., mirror-image, relative to the first conveyor shaft 17. Alternatively, it would also be possible to design the second conveyor shaft identically to the first conveyor shaft, but have it rotate in the opposite direction.

[0062] Paddles 19, such as those present as conveying structures on both conveyor shafts 17, 18, are known per se. When the corresponding conveyor shaft rotates, they convey the material to be processed in the intended direction by pushing it forward or, depending on the rotation speed, imparting momentum in the intended conveying direction. The paddles 19—or other conveying structures, such as helical conveyors, can be permanently welded to the actual shaft or otherwise attached to it, which solves the hygiene problems described above.

[0063] The upper conveyor shaft 18 and, in the illustrated embodiment, also the lower conveyor shaft 17 have a central area 31 without a paddle 19. Therefore, no conveying of material to be processed takes place in this central area.

[0064] Figure 1 also illustrates the possibility of the conveyor shafts 17, 18 having a conveyor shaft drive 21 which is independent of the feed roller drive 22 in that it has its own electric motor. This has the already mentioned advantage that the speed of the conveyor shafts 17, 18 can be set independently of the speed of the feed roller and can also be changed during operation. In the illustrated embodiment, the first conveyor shaft 17 and the second conveyor shaft are coupled to one another or to the conveyor shaft drive 21 in such a way that, driven by the conveyor shaft drive 21, they always rotate at a fixed speed ratio, for example 1:1 (i.e. at the same speed).

[0065] Alternatively, it would also be possible for the conveyor shafts to be driven by the feed roller drive, for example, via appropriate belts. Conversely, it is also possible for the first conveyor shaft 17 and the second conveyor shaft 18 to each have their own drive and their rotational speeds to be adjusted independently.

[0066] Fig. 1 also illustrates the conveyor shaft supply unit 23 separately from the feed roller supply unit 24; in reality, the supply units can optionally also be integrated into a common electronic unit.

[0067] The feed device also has a fill level monitor, which in the illustrated embodiment is formed by a radar sensor 27, as taught in Swiss patent application 448 / 2022 of April 14, 2022. Other fill level monitors, which determine the fill level, for example, by means of a capacitive sensor, a weight measurement, and / or optically and / or otherwise, are also an option.

[0068] Figure 3 illustrates an alternative embodiment, which differs from that of Figs. 1 and 2 in the shape of the collecting chamber 12. The collecting chamber 12 is divided into a chamber-like upper collecting chamber 41 with a surrounding, approximately vertical wall 51, and a lower collecting chamber 42 extending along the entire length of the feed roller. The upper collecting chamber can be in the shape of a box with an approximately rectangular outline or can have an approximately circular or slightly elliptical outline. On the upper side, the inlet 11 opens into the upper collecting chamber 41 in the form of at least one line—generally, there are several, for example, four, lines, for each of which the housing 2 has a nozzle or the like. The width (axial extent) of the upper collecting chamber is significantly smaller than the axial extent of the feed roller 14.As a result, the lower partial collecting space 42, in addition to a front and rear boundary and lateral boundaries 52, also has a horizontal upper boundary 53, which is located to the side of the first partial collecting space 41 and, under certain circumstances, also in front of and / or behind the upper partial collecting space.

[0069] A viewing window 44, indicated by a circumferential dashed line, is arranged and dimensioned such that it is not only present on the circumferential wall 51 of the upper partial collecting chamber, but also extends downward into the cover of the lower partial collecting chamber 42, so that at least the upper conveyor shaft 18 is visible through the window. The viewing window can be vertical or approximately vertical, at least in sections.

[0070] The viewing window extends axially close to the end sides of the lower partial collecting chamber, i.e. essentially to positions which correspond to the axial ends of the conveyor shafts 17, 18 and the feed roller 14 (more precisely: the axial ends of that part of the conveyor shafts / feed roller which comes into contact with the material to be processed).

[0071] Particularly in embodiments with a comparatively narrow upper collecting chamber 41, as shown in Fig. 3 and subsequent figures, a conveyor shaft drive 23 independent of the feed roller drive 22 is particularly advantageous. It has been shown that, especially in these embodiments, the best results are achieved when the speed ratio of the feed roller and conveyor shaft(s) is not constant, but can be adjusted to the material being processed and, if necessary, other parameters.

[0072] Figure 4 illustrates further optional features of a feeding device with an upper partial collecting chamber 41 and a lower partial collecting chamber 42 with at least one conveyor shaft 17, 18. In Fig. 4, the viewing window is not indicated for illustrative reasons, but a viewing window with the properties described above is also an option for devices with the features described with reference to Fig. 4.

[0073] Firstly, Fig. 4 shows that the surrounding wall of the chamber forming the upper partial collecting space 41 does not necessarily have to be vertical, but can be slightly inclined to the vertical. The angle of inclination α of at least part of the surrounding wall, i.e. a side wall, front or rear wall, can in particular be between 0° and a few degrees, for example it can be between 0° (vertical) and 10°, in particular between 0° and 7° or between 0° and 5°. In the case of a rectangular floor plan, in particular at least one wall - or two opposite walls, for example the two side walls or the front and rear walls as illustrated in Fig. 4) can be inclined to the vertical.A slight inclination of at least one area of ​​the surrounding wall can be advantageous in order to prevent so-called material bridges, through which larger air pockets can form inside the material to be processed - even if these are generally unproblematic due to the active conveyance of the material to be processed by the conveyor systems.

[0074] Second, Fig. 4 illustrates transport pipes 71 leading through the roller mill. These serve to transport processed material or other goods between devices and / or storage locations of the grain mill and do not necessarily have to be connected to the respective roller mill. For example, transport pipes can transport the processed material away, e.g., pneumatically, after it has passed through the roller mill.

[0075] Roller mills are often constructed as multiple roller mills (four-roller mills or with stacked pairs of rollers as eight-roller mills). For space reasons, it is often necessary for transport pipes to be routed through the roller mill – regardless of whether the transport pipes are used to discharge processed material from the respective roller mill or simply connect other elements of the grain mill. Since the collecting chamber extends further back in the upper area (see Fig. 2, where the front is on the right in the figure), the current state of the art often requires a solution in which the transport pipes are routed through the collecting chamber itself or in which the chamber must be restricted by notches or similar for the transport pipes. This is often structurally unsatisfactory.Measures discussed in the present text enable embodiments in which transport pipes are arranged in the axial direction next to the upper partial collecting space 41 and thus do not affect the collecting space.

[0076] In particular, the width of the upper part of the collecting chamber 41 can be selected such that even with a smallest roller length of 1 m there is still space on both sides for two inlet pipes each with a pipe diameter of, for example, 95 mm, which is why the width b of the upper part of the collecting chamber at the bottom is, for example, a maximum of approximately 550 mm, for example a maximum of approximately 500 mm and, in particular, without any aspiration channels leading laterally past the actual upper part of the collecting chamber 41, a maximum of approximately 450 mm.

[0077] Thirdly, Fig. 4 illustrates the principle that the processed material always seals the volume in the upper collecting chamber from below, in that the processed material always occupies the entire cross-sectional area, at least at the very bottom of the upper collecting chamber. For this purpose, the feeding device or the system in which the rolling mill with the feeding device is embedded is designed to constantly regulate the fill level 61 of the processed material during operation. The opening angle o of the material cone varies depending on the processed material and has a value of between 90° and 120°. The control system (see Fig. 5) of the feeding device is therefore designed, for example, to adjust the fill level in the upper collecting chamber 41 in such a way that sealing is always guaranteed with the steepest material cone (o = 90°) and also with a certain lateral offset of the material cone. The maximum lateral offset up to which sealing is guaranteed is, for example,up to 30 mm, up to 50 mm, or even up to 100 mm. For typical desired filling heights, this can also result in the criterion that the width b of the upper collecting chamber 41 is a maximum of approximately 500 mm, in particular a maximum of approximately 450 mm.

[0078] Figure 5 illustrates the control system 81, which can correspond to the control system of the entire roller mill (the same applies to another rolling mill) and can be integrated into the control system of an entire system or connected to it via suitable communication channels. The control system receives signals from the radar sensor 27 – and / or one or more other sensors for level detection – and controls the conveyor shaft drive 21 and the feed roller drive 22. Under certain circumstances, it also influences the flow of the incoming material, which is shown in Fig. 5 as an optional control of an inlet slide 85. In embodiments with the comparatively narrow upper collecting chamber 41, the control system is implemented in such a way that the above-described condition is met, according to which the material always seals off the volume towards the bottom of the inlet, for which purpose the separate conveyor shaft drive 21 is advantageous.Particularly when integrated into the roller mill's control system, the speed of the grinding rollers can also be controlled accordingly (grinding roller drive 82). A user interface 84 enables the input and / or output of information and commands by or to a user, e.g., manual control of the speeds of the feed roller and / or the conveyor shafts. Fig. 5 also illustrates the option of adjusting the feed gap in a motorized and controlled manner (feed gap adjustment 83 via the adjustable slide 15). In many embodiments, the feed gap is adjusted mechanically and when the feeding device is at a standstill, although feed gap adjustment during operation is also possible.

[0079] When the rotational speeds of the conveyor shafts and / or the feed roller are automatically adjusted depending on a fill level measured by the radar sensor 27, the sensor, the control system and the drives of the conveyor shafts and / or the feed roller form a control loop with the fill level of the material to be processed as a - for example, adjustable - setpoint.

[0080] Figure 6 shows a roller mill as an example of a rolling mill and, in addition to the feed device 1, also shows a grinding chamber 93 with a pair of grinding rollers 91, between which the grinding gap 92 is formed, into which the material to be processed conveyed by the feed roller 14 passes. Between an upper region of the upper partial collecting chamber 41, above the fill level 61, and the grinding chamber 93, in particular the region above the grinding rollers 91, there is, in the example shown, at least one aspiration channel 94. Such aspiration channel can be guided along the rear of the collecting chamber 12, as shown in Fig. 6. In addition or alternatively, aspiration channels can also be considered, which are guided laterally along the upper partial collecting chamber and, for example, along the rear of the lower partial collecting chamber.

[0081] Figure 7 illustrates very schematically a view of a double roller mill with a «narrow» inlet, ie with a feeding device of the type shown in Figures 3 and - TI -

[0082] 4, from above. The inlet 11 has connections for four pipes. In addition to the upper partial collecting chamber 41, an aspiration channel 93 runs along the side walls of the upper partial collecting chamber on both sides. The dashed line represents a subdivision between a front and a rear compartment of the upper partial collecting chamber, whereby the material to be processed is already divided in the upper partial collecting chamber between a portion for the front pair of grinding rollers (in Fig. 7, for example, in the lower half of the roller mill) and for the rear pair of grinding rollers (in Fig. 7, for example, in the upper half of the roller mill). The aspiration channels run below the upper partial collecting chamber between the lower partial collecting chambers for the two pairs of grinding rollers and the associated feed rollers and conveyor shafts.The transport pipes 71, which do not necessarily belong to the roller mill, also run between the lower partial collecting spaces for the two pairs of grinding rollers and the associated feed rollers and conveyor shafts.

[0083] Figure 8 schematically illustrates the possibility of equipping the second conveyor device—here, the second conveyor shaft 18—with mixing structures, i.e., structures that move and mix the material to be processed without systematically conveying it in one or the other axial direction. These can be formed, for example, by rods projecting outward from the shaft core, or by any other structures suitable for a mixing process. These mixing structures are located in a central area below the inlet. The same possibility also exists for the first conveyor device (first conveyor shaft 17).

[0084] Based on Figures 9-17, the following very schematically outlines possible configurations for the second conveyor device, as an alternative to a single-piece shaft with a shaft core and with opposing conveyor structures arranged on both sides, as outlined in the previous examples. According to Figure 9, the second conveyor device can be multi-part, namely, in Fig. 9, two-part, with a second conveyor shaft on each side, with the second conveyor device being interrupted in the area below the inlet. The drive in Fig. 9 is provided by the conveyor shaft drive 21 with the aid of suitable transmission means, e.g., at least one belt.

[0085] However, it is also possible that in a solution as outlined in Fig. 9, the second conveyor shafts 18 each have their own drive 112, as outlined in Figure 10.

[0086] Figure 11 illustrates the possibility of the second conveyor shaft(s) 18 not extending axially, but at an angle to the axis of the feed roller and the first conveyor shaft. In Fig. 11, the second conveyor shafts are vertical, so that they convey the material conveyed to the end faces upwards, from where it can fall back down laterally and be again captured by the first conveyor shaft or be passed through the feed gap, and in any case, cannot accumulate at the end faces.

[0087] Figure 12 schematically shows the possibility that the second conveying means are not formed by a conveyor shaft, but by a periodically moving ram 118, which pushes accumulating processing material inwards.

[0088] Figure 13 shows, as a further possibility, a second conveying means in the form of a pivoting plate 119, which also moves accumulating processing material.

[0089] According to Figure 14, a compressed air nozzle is used as the second conveying means, which blows the accumulating material to be processed inward. Figure 15 very schematically illustrates the possibility that the second conveying means may be present as a second conveyor shaft 18, but that this is not arranged above (and / or to the side) of the first conveyor shaft, but rather as a "shaftless" (or "soulless") screw conveyor that can accommodate the first conveyor shaft within its interior—i.e., the screw conveyor can be approximately coaxial with the first conveyor shaft.

[0090] Figure 16 also shows very schematically a roller 122 with conveyor structures which can be arranged vertically or horizontally in order to convey accumulated processing material away from the end side.

[0091] Figure 17 illustrates a circulating belt with conveyor structures, which can be arranged, for example, in such a way that it engages on one side (above the dotted line in Fig. 17, for example) in the area above the first conveyor device, while it runs back in an area (in the example below the dotted line in Fig. 17) in which there is no contact with the material to be processed.

[0092] Figure 18 shows a configuration of the collecting chamber 12, which differs from the configuration according to Fig. 2 in that the rear wall of the collecting chamber forms a shoulder 121 at the narrowest point—directly above the feed roller. This shoulder 121—in the form of a vertically extending wall section of the otherwise sloping rear wall—effectively counteracts bridging in the case of poorly flowing ground material.

[0093] Figure 19, finally, illustrates the principle of mixing bars 122 on the second

[0094] Conveyor shaft 18. It can also be seen in Fig. 19 that the paddles 19, ie the structures for conveying away from the end faces on the second conveyor shaft, are arranged only on the very outside, which, depending on the constellation, may be sufficient to achieve the effect discussed in the present text.

[0095] As an alternative to the embodiments shown, all aspects of the invention can also be realized if the inlet is not mounted centrally but laterally.

Claims

PATENT CLAIMS Feeding device for a rolling mill for food processing, comprising a collecting space (12) into which a processing material can be fed via an inlet, and a feed roller (14) with an axis, wherein the feed roller (14) is arranged on the underside of the collecting space, and wherein processing material present in the collecting space (12) can be conveyed away from the collecting space by the feed roller (14), wherein the feeding device further comprises, above the feed roller (14), a first conveying device for conveying the processing material in the collecting space (12) in the axial direction towards at least one end side, characterized by a second conveying device for conveying processing material conveyed by the first conveying device away from the end side. Feeding device according to claim 1,wherein the second conveyor is configured to convey the processed material conveyed by the first conveyor in a direction opposite to the axial direction. Feeding device according to claim 1 or 2, wherein the second conveyor is arranged above the first conveyor. Feeding device according to one of the preceding claims, wherein the first conveyor is formed by a first conveyor shaft (17) and the second conveyor is formed by a second conveyor shaft (18).

5. Feeding device according to claim 4, wherein the first conveyor shaft (17) and / or the second conveyor shaft (18) has a shaft core and paddles (19) which are firmly connected to the shaft core, for example welded.

6. Feeding device according to claim 4 or 5, wherein the first conveyor shaft and the second conveyor shaft are coupled to each other and / or to a common conveyor shaft drive in such a way that they are connected to a fixed Rotate rotation speed ratio.

7. Feeding device according to one of claims 4-6, wherein at least the second conveyor shaft (18) is free of paddles (19) and other conveyor structures in a region below the inlet (11).

8. Feeding device according to one of claims 4-7, wherein the first conveyor shaft (17) and the second conveyor shaft (18) each have a first and second outer region with conveyor structures, wherein the conveyor structures of the first and second outer regions convey in opposite directions.

9. Feeding device according to one of claims 4-8, wherein the first conveyor shaft and / or the second conveyor shaft has mixing structures (101, 102, 122) for actively mixing the material to be processed in a region below the inlet (11). Feeding device according to one of the preceding claims, wherein the first and second conveyor devices have a conveyor device drive that is independent of a drive of the feed roller. Feeding device according to claim 10, wherein a conveying capacity of at least the first conveyor device is adjustable. Feeding device according to one of the preceding claims, wherein the collecting space has a lower partial collecting space and an upper partial collecting space, wherein the upper partial collecting space is formed by a downwardly open chamber with a circumferential wall and opens into the lower partial collecting space at the bottom, wherein an extension of the chamber in the axial direction is smaller than an axial extension of the feed roller (14) and the conveyor devices. Feeding device according to claim 12, wherein the collecting space (12) has a viewing window that extends downwards at least as far as the lower partial collecting space (42).Rolling mill, comprising at least one processing chamber (93) with at least one pair of processing rollers (91), between which a processing material can be comminuted and / or flaked, and a feeding device (1) according to one of the preceding claims, which is arranged such that processing material conveyed by the feed roller (14) reaches the processing chamber (93). Rolling mill according to claim 14, comprising a gas-carrying aspiration channel (94) between an upper region of the collecting space (12) and the processing space (93). Rolling mill, comprising a feeding device with a collecting chamber (12) and a processing chamber (93) with at least one pair of processing rollers (91), between which a processing material can be comminuted and / or flaked, wherein the collecting chamber (12) has a lower partial collecting chamber (41) and an upper partial collecting chamber (42), wherein the upper partial collecting chamber (41) is formed by a downwardly open chamber with a circumferential wall and opens into the lower partial collecting chamber (42) on the underside, wherein an extension of the upper partial collecting chamber in the axial direction is smaller than an axial extension of the feed roller (14), wherein a processing material can be fed to the upper partial collecting chamber (41) via an inlet (11), wherein the feeding device further comprises a feed roller (14) with an axis,wherein the feed roller (14) is arranged on the underside of the lower partial collecting chamber (42), wherein processing material present in the lower partial collecting chamber can be conveyed from the lower collecting chamber into the processing chamber (93) by the feed roller, and wherein the feed device further comprises a first conveying device for conveying the processing material in the lower partial collecting chamber (42) in the axial direction, characterized in that the rolling mill further comprises at least one gas-conducting aspiration channel (94) between the upper partial collecting chamber (41) and the processing chamber (93). Rolling mill according to claim 16, comprising a control system (81) configured to operate the feed roller (14) and the at least one conveying device such that the processing material always seals the inlet (11) towards the lower partial collecting chamber (42).

18. Rolling mill according to claim 17, comprising a fill level monitor for determining a fill level in the collecting space, wherein the control is configured to take the determined fill level into account when setting a quantity of processing material entering the collecting space through the inlet and / or a rotational speed of the feed roller (14) and / or a conveying capacity of the first conveying device.

19. Rolling mill according to one of claims 16-18, wherein the collecting chamber (12) has a viewing window extending downwards at least to the lower partial collecting chamber (42).

20. Rolling mill according to one of claims 16-19, wherein the aspiration channel (94) or at least one of the aspiration channels is guided laterally or rearwardly along the upper partial collecting chamber (41) and rearwardly along the lower partial collecting chamber (42) and ends above the pair of processing rollers (91).

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