Technical Field

The present invention concerns a feeding device for granular material which has an avalanching tendency to flow outward into a pile when not being contained. More specifically the present invention regards a feeding device for granular material in accordance with the claims.

Background of the Invention

In many instances there exists a need to move granular materials from one position to another. An example of such a case is when granular material is stored in a hopper, storage, magazine or the like to be fed to a furnace, container, other processing machinery or similar. To solve the task of moving the granular materials, a number of different types of feeders (dischargers) have been developed during the years. Examples of those known feeders consist of different types of stoker feeders, screw feeders and similar designs. Presently there is a lack of feeders (dischargers) for feeding and moving granular materials such as pellets, stored in smaller magazines.

When storing bio-pellets (fuel pellets) for heating of single family homes and smaller apartment buildings, there are a number of problems with storing the pellets effectively and in moving the pellets from the magazine to the burner (in the heater). Problems with this storage are usually that only smaller spaces are available, such as a nearby room in the basement as storage for the pellets.

The lack of adequate space adjacent to the heater usually means that only a small buffer storage (such as a weekly or a daily one) is available in connection to the heater. From the buffer storage the pellets are fed by means of a screw feeder to the burner connected to the heater or similar. The limited buffer storage may entail that the supply might last for only a few days of heating.

This limited storage capacity limits the possibility of purchasing pellets in bulk shipment resulting in that pellets may only be bought in bags (sacks). The bags are then stored at another place to be moved and emptied into the buffer storage by hand. Such handling is both time consuming and requires planning to assure adequate heating. Furthermore the cost of i pellets is higher in bags than if procured in bulk form. Handling pellets in bulk shipments is also more environmental friendly as no bags are needed to be recycled or scraped. Presently bulk shipments of pellets are not available under a certain quantity.

In order to ease the storage and feeding (discharging) of pellets, magazines with feeders (dischargers) have been developed. One example of a magazine with discharger is described in patent EP 167123. The discharger in this design is a screw conveyor placed at the bottom of the magazine. In order to effectively empty the magazine the bottom of the magazine is built with two sloping surfaces towards the screw feeder of which at least one is arranged to vibrate. One problem with this design is that the available space for storage is not optimized. The design is not functional in limited spaces. The design also differs significantly from the present design.

A number of types of magazines for pellets aimed to utilize the space available for the storage volume are known. An example is patent SE525448, a container for storage of pellets with a discharger. The sides of the container can be moved in order to push the pellets to the centre of the container. The design has a number of shortcomings. For instance the pellet magazine is equipped with a screw discharger, which is not gentle to the pellets to be fed. The design also differs significantly in other ways from the actual design.

One type of design of a pellets magazine including a flexible bottom is known through patent SE528137. In the patent a pellets magazine which in the bottom is equipped with a conventional discharger type bottom screw is described. The pellets magazine is furthermore equipped with airbags which move the pellets from the sides towards the screw. The design, not only has the disadvantages of the screw discharger, it also needs a compressor to fill the airbags when the discharge takes place. The design not only has the increased cost of the compressor, it also emits more noise while in use and demands more energy than the present invention.

Yet another patent, JP100142A may initially be regarded as comparably similar to the present invention (0900089-4). However there are a number of important differences described in the following.

The design as per JP100142A is basically built up as a conveyor (belt or chain or similar) with one or several rollers attached to strands of belt or chains, which follows the belts

(chains) around in the direction the conveyor is driven. The roller (rollers) is guided around under a cloth or similar cover on which materials are stored. As the roller moves under the cloth the materials are subjected to be pushed ahead by the roller.

The design according to JP6100142A has a large number of shortcomings in comparison to the present invention. The greatest is that it is considerably more space demanding, especially regarding the height requirement. The present invention (0900089-4) utilizes all available height down to the available floor level.

The present design is reciprocating, that is to say, returning to its end after a full cycle of feed resulting in leveling off the height of the material in the magazine. This action will also enhance break-up of the stored material, which has a tendency to stick together. As the discharger returns instead of continuing around a pulley of some design as the one in patent JP6100142A, an improved transfer of the materials to a discharging hopper or a following process is achieved, mainly resulting in a lower transfer point again allowing more space for storage.

In cases where there is already enough materials to be fed out at the discharging end, there is no need for the discharger to return the entire way back (or as with the discharger as per

JP6100142A to rotate with at least one roller through and past the back wall of the storage), but can be guided by control equipment (via timer, level indicator or similar) to return only a suitable distance. This is more efficient, less energy consuming and results in less wear and tear. Another advantage with the reciprocating motion is that at shorter distances, the discharger can be driven by a rotating screw at either side (in the middle or at both sides) and with a corresponding nut (nuts) fixed to the discharger, alternatively a cylinder (pneumatic or hydraulic), ratchet drive, excenter drive or other drives as less expensive alternates.

The present invention will be less expensive to build, as the one as per JP6100142A is actually a conventional conveyor equipped with one or more similar rollers and additionally requires some sort of support structure. The present invention on the other hand can be supported in most cases directly on an existing floor.

As the present invention is comparably simpler it will also be simpler to maintain and less maintenance consuming. The total weight of the discharger should be considerably less (and thereby in most cases less expensive to build) meaning less demand on load on the floor and even, in certain cases, conclusive for a given space. Another advantage with the present invention is that it is possible, from time to time, to change the dischargers working area in order to better utilize the stored volume depending on the circumstances.

In regards to the above it should be self evident that the present invention (0900089-4) is new in comparison to the prior art and has inventive step.

Brief Description of the invention Concept

The main purpose of the present invention is to achieve a much improved and more efficient feeder (discharger) for granular materials. Another aim of the present invention is to make a feeder (discharger) that can for example be utilized in storage for example of fuel pellets or similar materials. Yet another aim of the present invention is to achieve a safe, gentle, space saving and reliable feeder (discharger).

Detailed Description of the invention

The present invention will be described in detail in the following text with reference to the enclosed schematic drawings that in an exemplifying purpose show the current preferred embodiments of the invention.

Fig. IA and I B shows schematically the present invention seen in perspective. Fig. 2 shows the present invention placed in a storage area seen from the side. Fig. 3 shows the present invention placed in a storage area seen from the front.

Fig. 4 shows more in detail an alternate embodiment of the present invention placed in a storage area seen in a cross section from the front.

Fig. 5 shows a second alternate embodiment of the present invention which includes a linkage system seen in a cross section from the side.

Fig. 6 shows a third alternate embodiment of the present invention seen in a view from the side. With reference to the figures a feeder (discharger) 1 is shown, according to the present invention, which is intended to be used for moving granular materials from storage 2 (shown in figures 2 and 3), container, magazine or the like. Granular materials refer to such materials as fuel pellets, wood chips, saw dust and the like. With granular material is also meant in this patent application, all materials that flow viscously and the like. The feeder 1 can be used for discharging (moving) a number of different kinds of granular materials in and out of a large number of different types and variants of storages, hoppers, magazines and the like. Therefore the exemplified granular materials and storage described herein is not limiting for the scope of the present invention. Figures 1 and 2 show the feeder 1 placed in storage 2, where the feeder is preferably used for moving fuel pellets or the like, in and out from storage 2. The storage 2 consists of an enclosure including the sides 3 and bottom 4. The bottom 4 can be the floor, or the like, in the space where the storage (magazine) 2 is to be located. The enclosure can advantageously also contain a roof (top) 5 or the like. The storage (magazine) 2 can in one of the ends, the discharging end, contain a discharging hopper 6 (intermediate hopper) from which a conventional feeder 7 (e.g. a screw feeder) feeds the granular material to, for instance, a heater.

The feeder (discharger) 1 , according to the present invention, contains at least one layer 8 of a flexible material such as a cloth or similar, that is mounted as an inner bottom in the storage (magazine) 2. Granular material is intended to be temporarily stored on the flexible layer 8. The flexible layer 8 is at least flexible in the length direction of the magazine. The flexible layer 8 is preferably flexible in both the direction of the feed and crosswise and forms an open bag (sack) mostly supported by the floor in the room for the storage. Alternately the inner bottom 9 can be supported on any type of a raised plane 10 alternatively several raised planes 10 can be used. The raised plane can be useful for access under the inner bottom. This can for instance improve cleaning under the inner bottom. Alternately the flexible bottom can be aiτanged to be completely free hanging without contact with the underlying floor, bottom or similar.

The flexible layer 8 can, for instance, be of a rubber coated cloth, taip material or similar material. Alternately the flexible layer can be of any other suitable material for the intended puipose.

The edges of the flexible bag (made of the flexible material) are at least fixed in the front and rear end of the magazine, that is to say, the ends of the feeder's (discharger's) working area. Preferably the flexible material is also fixed along the elongated sides, that is to say, also fixed to the sides parallel to the moving direction of the feeder (discharger). Alternately the flexible sack-shaped material is fixed to a frame construction. The frame construction can be placed in the storage (magazine). Alternately the frame construction can constitute the storage (magazine). The storage (magazine) consists then of the space formed by the flexible material.

The edge of the sack-shaped flexible material shall be fixed on a vertical height that is relatively close to the upper edge of the roller 11 described in the following. The feeder (discharger) 1 includes a roller 1 1 , that covers nearly or even a little more of the width of the storage (magazine) 2. The roller 1 1 or rollers, if more than one, is preferably supported via bearings to a discharging unit 12, trolley or similar.

The discharging unit 12 is arranged to move along the whole or a part of the length of the storage (magazine) 2. Preferably the discharging unit 12 travels mainly horizontally on at least one guide rail 13, profile or similar. The discharging unit 12 is through the bearings 14 flexibly supported to the guide rail 13. In the figures the bearings 14 are formed by wheels on bearings. The wheels could be made up of ball bearings or similar. Within the scope of the present invention the bearings 14 can be of other types of bearings applicable for the purpose, for instance sleeve type bearings. The discharging unit 12 is arranged to be traversable along the whole or a part of the length of the guide rail. The discharging unit can on the other side (non driven side) be supported on at least one carrying rail, guide rail or similar that mainly runs parallel to the guide rail. Alternatively the discharging unit can on its other end be supported on the floor plane. In alternate embodiments it is conceivable to arrange the discharging unit cantilevered from its other end.

The motion of the discharging unit 12 along the guide rail is managed by preferably at least one drive unit, which can consist of or include a chain drive, ball screw or another for the purpose suitable drive system. Preferably the drive system consists of one or more electric motors 15 which via at least one sprocket 16, pulley or the like works a chain, line or similar to move the discharging unit along the guide rail. In the figures IA and IB the connecting points for the chain 17 are not shown, the chain is connected in a, for the purpose, suitable manner.

Furthermore the design includes at least one control unit (not shown in the figures), which is intended to control the motion of the discharging unit along the guide rail. In alternate embodiments the roller 1 1 can be driven, that is to say, arranged to rotate relative to the flexible material. The drive is accomplished by at least one electric motor connected to a transmission (not shown in the figures) as per an earlier known technique. Alternatively the roller can be arranged to rotate by the same drive as the motion of the discharger. As known techniques are used for the drive it is not further described in this patent application. The motion of the discharging unit can be continues or intermittent with fixed or variable speeds.

The roller 1 1 is furthermore so arranged that it both lifts a part of the flexible material 8 (cloth) and traverses (moves) mainly in a horizontal direction under the cloth 8. By the motion under the cloth 8 the granular material thanks to its tendency to slide will mainly fall to the side of the roller 1 1 which is behind in the direction of travel (travel direction). Instead the material in front of the roller 1 1, is lifted up and when the roller 1 1 is moved in a known way, to and fro, the material is pushed (moved, rolled) towards the open end of the storage (through at least one opening, lower wall, lower edge or the like) that is to say to the discharging hopper shown in the example in the figures.

In order to reduce the energy consumption for moving the roller under the flexible material the roller can be arranged to be lowered in one of the directions (shown in figure 5). The motion of the roller 1 1 up and down can be executed by one or several bands 18 or wires (lines) which actuate a linkage system 19, which at a pulling force lifts the roller and at return will lower the roller. The bands or lines which then are driven will thereby pull the discharging unit to and fro under the cloth as soon as the roller has reached the upper or the lower vertical position respectively.

In still another embodiment of the present invention it is thinkable that the return motion of the roller is eased by holding the flexible bottom in the upper position by one or several lines 20, load securing straps or similar, which are arranged from the back wall, over the roller 1 1 and to the front wall. In this case, at least one additional and lower roller 21 or wheel (wheels) is required, in which case one or more of the lines also can be arranged to guide the discharging unit. The lower roller can, as an alternate to the earlier described drive unit, be driven and thereby move the discharging unit under the flexible material (the cloth). The lower roller can also be arranged to carry the discharging unit.

For the professional in the field such obvious components as cables, brackets, bolts and similar components of earlier known techniques are not shown in the figures and in the description. These are included to the extent necessary in order for the intended technical effect to be reached.

Even if certain preferred embodiments have been described in detail, variations and modifications can within the scope of the invention become evident for specialists in the field and all such are regarded as falling within the scope of the following claims. For example it is conceivable that the invention can be used in other applications than those described herein. For instance, it is thinkable that the invention can be used for the handling of golf bolls, plums, and other fruits and similar materials. This application is valid for such cases, but the present invention can of course also be used for other materials and storages.

The present invention can also be utilized as a procedure for discharging granular material by the use of the described feeder (discharger).

Advantages of the Invention

With the present invention a number of advantages can be achieved. The most obvious one is that a less spacious storage for granular materials is achieved in a given space. Furthermore, equipment that more gently moves granular material is achieved. Another advantage with the present invention is that materials are lifted up and into a following handling process. Still another advantage with the present invention is that it is simple and less expensive to build and utilize.