Plant for storing, handling and feeding loose materials and associated operating method

Abstract: A plant for storing, handling and feeding loose materials and the associated operating method; the plant comprises: at least one filling station (2) for container means (8) which can be handled by means of lifting vehicles (4) such as fork-lift trucks; at least one storage area (5) for depositing the containers (8) in standby; and a series of stations (6) for feeding machines (7) which use the materials. The container means are constituted by silos (8) which have a limited capacity and have, in a downward region, a multipurpose grid-like structure (8a) for resting on the ground, for the modular mutual stacking of the silos (8) and for the mating of the silos (8) with the conventional lifting elements (4a) with which fork-lift trucks (4) are equipped. The silos (8) can be arranged, at least in the storage area (5) and in the feeding stations (6), so as to be stacked on multiple levels (PS, PT).

Description: The present invention relates to a plant for storing, handling and feeding loose materials and to the associated operating method. Granular and powdery loose materials are employed in many industries in order to produce manufactured articles or to prepare compounds or simply to supply them as raw materials. One of these industries is the ceramic industry, which uses the raw material (clay) in powder form to produce tiles and dyes for said tiles, which are also in powder form. Accumulating stocks of these materials, handling them and using them entails building of very large plants which must be placed inside production facilities. These plants currently consist of a series of large silos connected to a supply source and to the user machines, constituted by presses in the specific case, by means of portions of conveyor belts which are arranged in mutual succession so as to connect the supply stations, said silos and said presses in the facilities. The silos used are so tall that on installing them it is necessary to alter the building by raising the roofs. Moreover, the entire handling system of all the conveyor belts is very complicated, highly structured and is often subject to interruptions due to faults, that cause the blockage of the production line. Conventional systems require also the presence of overhead walkways on which the operators assigned to monitoring and general maintenance can walk in order to reach all the elevated areas. In turn, building and using these walkways depends on compliance with strict accident-prevention measures, whose costs further affect the management of the plants and finally affect the end products. According to a second solution, provided mainly in order to eliminate the need to perform the above-mentioned construction work, the systems for storing, handling and feeding loose materials are arranged exclusively at ground level. In practice, these plants are constituted by a storage area in which small low-capacity silos are accumulated, arranging them side by side and ordered in rows and columns; the materials are introduced in these silos in an already-premixed state, when required, according to percentages which can vary as necessary. In this storage area, which in practice can be divided ideally into sectors, in each of which the materials having identical characteristics are catalogued and contained in the small silos, which are also mutually identical, automatically-controlled vehicles move along corridors provided appropriately between the rows and columns in which the silos are arranged. In response to the requests of the user machines, the vehicles first determine the sector in which the material having the required characteristics is accumulated, then remove the silos that contain it in the required amounts, and convey them for emptying and use to the inlet front of the conveyors that serve each one of the machines and onto which the material is unloaded. In the plant solution that uses large-capacity silos and in the one that uses small silos handled at ground level there are drawbacks which mainly arise from the overall dimensions of the respective structures, in a vertical direction for the former and in a horizontal direction for the latter. Moreover, mention has already been made, in the first solution, of the onerous building work required for installation, of the complicated network of conveyors that must be built for the operation of the plant and of the plant infrastructures for managing and controlling the plant without this leading to an optimum yield. In the second solution, it is important to consider the impossibility to handle automatically silos having mutually different structural and capacity characteristics, and the poorly optimized facility space utilization. A typical prior art plant for the storing, handling and feeding of loose material is known from EP-A-0 841 137. The aim of the present invention is to solve the above-described problems of the prior art by providing a plant for storing, handling and feeding loose materials and the associated operating method which allows to considerably reduce the overall dimensions, reduces as much as possible the number of large silos and proportionally reduces the extent of any building work required for installation and of the infrastructures for connection and walking between the various regions and stations, and which allows to use materials handling means which are normally commercially available. This aim, this object and others are achieved by a plant for storing, handling and feeding loose materials, comprising at least one filling station for containment means which can be handled by means of lifting vehicles usually known as fork-lift trucks; at least one storage area for depositing these containers in standby; a series of stations for feeding machines which use the materials; characterized in that the containment means are constituted by silos having a limited capacity and have, in a downward region, a multipurpose grid-like structure for resting on the ground, for the modular mutual stacking of the silos and for the mating of the silos with the conventional lifting elements with which fork-lift trucks are equipped, the silos being arrangeable, at least in the storage area and in the feeding stations, so as to be stacked on multiple levels. Advantageously, the associated method for storing, handling and feeding loose materials consists in providing, in a facility, multiple small silos, each loaded with material divided according to its organoleptic characteristics and taken from a filling station; in depositing and mutually stacking the filled silos in at least one general central storage area; in conveying, by means of conventional vehicles, the filled silos between the storage area, stations for feeding user machines and vice versa; in arranging the silos in the stations on multiple stacked levels, respectively upper feeding levels and lower reserve levels; in mixing, in the stations, volumes of materials taken from the feed silos in order to obtain materials having presettable characteristics; in feeding the user machines with the materials having the preset characteristics. Further characteristics and advantages will become apparent from the following description of a preferred embodiment of a plant for storing, handling and feeding loose materials and of the associated operating method, illustrated only by way of non-limitative example in the accompanying drawings, wherein: Figure 1 is a top view of a plant for storing, handling and feeding loose materials according to the invention; Figure 2 is a schematic enlarged-scale front view of a feeding station; Figure 3 is a schematic top view of a detail of conveyor means which are arranged, in the plant according to the invention, upstream of user machines. With reference to the above-cited figures, 1 designates a plant for storing, handling and feeding loose materials. The plant 1 comprises at least one filling station, generally designated by 2, for filling containment means 3 which can be handled by means of lifting vehicles 4, usually known as fork-lift trucks, which have onboard conventional weighing devices associated with the forks 4a. In the filling station 2 there is a limited number of large silos 2a of a conventional type and of the usual large size, in which the materials in the loose state are poured; these materials are carried to the station 2 by means of trucks 2b and are loaded at an elevated level by means of the conveyors 2c. In addition to the filling station 2 there is at least one storage area 5 for depositing the containment means 3 on standby to be used, and there is a series of stations 6 which feed corresponding machines which use the materials, specifically presses 7 for forming ceramic tiles. The containment means 3 are constituted by silos 8 which have small dimensions and a limited capacity and have, in a downward region, a multipurpose grid-like structure 8a meant for resting on the ground, for the mutual modular stacking of the silos 8 and for the mating of the silos with the conventional lifting elements, i.e., forks 4a, of the fork-lift trucks 4. The silos 8 can be arranged, when they are placed in the storage area 5 and in the feeder stations 6, so as to be stacked on multiple levels. Each one of the feeder stations 6 is composed of a frame 9 with at least two superimposed platforms: a first platform PT at ground level, on which a battery of reserve silos 8 is placed, and a second platform PS, which is raised and correspondingly lies above the platform PT in order to support another battery of silos 8 which, when used up, can swap places with the reserve silos; the silos 8 placed on the PS are adapted to unload the material onto conveyor means, in practice a belt conveyor 10, whose active branch 10a lies directly below the outlets of the silos 8 and whose output front 10b is located at the presses 7. Like the fork-lift trucks 4, the conveyor 10 also has weighing elements 11; in the specific case, the weighing elements are arranged contiguously with the active branch 10a, practically almost in sliding contact with the lower face thereof, and are alternated with the unloading silos 8. Screening means 12, mixing means 13 and conveyor means 14 for the processed material that is falling towards the presses 7 are further interposed, at each output front 10b of each conveyor 10, between the conveyor and the corresponding press 7 in a cascade configuration. The screening means 12 are constituted by a flat screen 12a with a preset porosity and have conventional elements adapted to make them vibrate. The mixing means 13 also are constituted by a conventional structure consisting of a cylindrical drum 13a which has, at its ends, respectively a loading port and an emptying port and inside which mixing paddles are fitted; the drum 13a has a rotary motion about its own axis, and the materials having different coloring and granulation/organoleptic characteristics are introduced therein. From the drum 13a, the materials are then unloaded into the conveyor means 14, constituted by a hopper 15 which is internally divided into sectors 15a in order to receive and keep separate materials whose characteristics are, for each of them, homogeneous; the hopper lies above a battery of other hoppers, into which the materials are poured and which are in turn placed above the presses 7 in order to feed them with volumes of material having characteristics different from each other. The multipurpose grid-like structure 8a is constituted by a flat base 8b in which there are horizontal parallel seats in which it is possible to insert the conventional forks 4a of a fork-lift truck 4; a set of four pillars 8c for supporting the silo 8 rises from the base. The base 8 forms, in the lower region, a seat 8d in which it is possible to snugly place the upper edge of a silo 8 so that it is superimposed thereon. The operation of the invention, reflecting also the operating method according to the invention, is implicitly included in the above description. It is further specified hereinafter by reference, merely by way of example, to a plant used in the ceramics industry for tile-making, but it can be used in the same manner whenever loose material is handled. The coloring materials in powder form required to provide the decorations of the tiles reach the filling station 2, being carried by the trucks 2b, in the loose state or already placed inside the respective silos 8, divided by color or mixture or particle size. If these materials are loose, they are introduced in the large silos 2a of the station 2 and are brought to the filling level by the conveyors 2c. In the alternative case in which the materials are already placed in the small silos 8 when they are delivered by the trucks 2b, the silos are stacked directly inside the storage area 5, ordered by rows and columns and optionally stacked on each other, by using the fork-lift trucks 4: for this purpose, the bases 8b form, in a downward region, the seats 8d in which the corresponding upper edges of the silos 8 fit snugly in the stacked configuration. The silos 8 containing the coloring materials meant to be used by the presses 7 are conveyed to the feeding stations 6. Essentially, the feeder silos 8 are placed on the frame 9 after being taken from the storage area 5 with the fork-lift trucks 4, whose forks 4a mate with the bases 8b, and are raised by the fork-lift trucks up to the resting level, while other corresponding reserve silos 8 are placed below them. The required amounts of the coloring materials are extracted from the feeder silos 8 and are deposited in each case onto the conveyor 10 and weighed by the weighing elements 11 to check the extracted amounts. The materials fall from the conveyor 10, after passing through the flat screen 12a, into the drum 13a, in which they are mixed in order to obtain the required particle size or shades of color. The drum 13a discharges the treated material into the corresponding sector 15a of the hopper 15, and from there the material is in turn discharged into a designated hopper of the other hoppers that feed the presses 7 for forming the tiles. When one of the feeder silos 8 becomes empty, by using the fork-lift truck 4 it is taken from its elevated position on the frame 9 and replaced with one of the reserve ones located below the frame; the entire process is performed rapidly and without having to interrupt the production cycle of the presses 7. The empty silos 8 are then removed and transferred to the filling station 2 to be refilled; refilling is performed by placing them sequentially below the discharge outlets of the large silos 2a; the amounts poured into the silos 8 are checked in real time by means of the weighing devices, optionally preset to required values, which are carried onboard the fork-lift trucks 4; once filling has been completed, the silos 8 are returned to the storage area 5 to wait for reuse; other full silos 8, ready to replace the feeder silos when their content is used up, are placed in the positions left free between the reserve silos, inside the stations 6. All the silos 8 can have mutually different dimensions and capacities despite being used simultaneously; for example, the silos that must contain a material that is used more than the others in the production cycle can be larger, without thereby reducing the operating capacity of the plant 1. In practice it has been observed that the above-described invention achieves the intended aim, i.e. it allows to provide a plant for storing, handling and feeding loose materials, which is substantially more compact than the prior art, is at the same time highly flexible in its management, and can use conventional means such as fork-lift trucks and trucks for the different handling operations. The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept, as defined in the appended claims. In practice, the materials employed, as well as the shapes and the dimensions, may be any according to requirements without thereby abandoning the scope of the protection of the appended claims. Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims: A plant for storing, handling and feeding loose materials, comprising at least one filling station (2) for the filling of container means (3) which can be handled by way of lifting vehicles (4) such as fork-lift trucks; at least one storage area (5) for depositing the containers (3) in standby; a series of stations (6) for feeding loose material to machines (7) which use the materials; characterized in that said container means are constituted by silos (8) which have a limited capacity and have, in a downward region, a multipurpose grid-like structure (8a) for supporting said silos (8) on the ground, for the modular mutual stacking of the silos (8) and for the mating of the silos (8) with the lifting elements (4a) with which said lifting vehicles (4) are equipped, said silos (8) being arrangeable, at least at said storage area (5) and at said feeding stations (6), so as to be stacked on multiple levels (PS, PT). The plant according to claim 1, characterized in that each one of said filling stations (2) is composed of a frame (9) with at least two superimposed platforms, a first platform (PT) at ground level for depositing a battery of reserve silos (8) and a second elevated and correspondingly superimposed platform (PS) for supporting a battery of feeder silos (8) whose position can be swapped with said reserve silos (8) and which are adapted to discharge said material, conveyor means (10) for conveying said material being further provided, their active branch (10a) being arranged below said feeder silos (8) and their output front (10b) being located at said user machines (7). The plant according to claim 2, characterized in that said conveyor means (10) are provided with weighing elements (11) which are arranged contiguously with respect to said active branch (10a) the weighing elements being alternated with said feeder silos (8) along the length of the conveyor means (10). The plant according to claim 1, characterized in that said lifting vehicles (4) are provided with conventional onboard elements for weighing said containment means (8). The plant according to claim 2, characterized in that screening means (12), mixing means (13), and conveyance means (14) for conveying the processed material towards said user machines (7) are placed in a cascade configuration at said output front (10b). The plant according to claim 5, characterized in that said screening means (12) are constituted by a flat screen (12a) which is actuated so as to vibrate and is arranged directly below said output front (10b). The plant according to claim 5, characterized in that said mixing means (13) are constituted by a cylindrical drum (13a) which is provided, at its ends, with corresponding ports for loading and discharging the material and is provided with a rotary motion. The plant according to claim 5, characterized in that said conveyance means (14) are constituted by at least one hopper (15) which is installed upstream of the user machines (7) and is provided with selector means (15a) for maintaining the separation of the material discharged by said mixing means (13). The plant according to claim 1, characterized in that said multipurpose grid-like (8a) structure is constituted by a substantially flat base (8b) in which there are horizontal parallel seats which can be coupled to the conventional forks (4a) of a fork-lift truck (4) and from which there rises a set of four pillars (8c) for supporting the silo (8), said base (8b) forming, in its lower portion, a seat (8d) for the engagement and resting of the upper edge of a silo (8). A method for storing, handling and feeding loose materials, characterized in that it consists in preparing, in a production facility, a plurality of silos (8), each loaded with material divided according to its organoleptic characteristics and taken from a filling station (2); in depositing and mutually stacking said loaded silos (8) in at least one general central storage area (5); in conveying with conventional vehicles (4) said loaded silos (8) between the storage area (5) and the series of stations (6) for feeding user machines (7) and vice versa; in arranging said loaded silos (8) in said stations (6) on multiple stacked levels (PS, PT), respectively upper feeding levels (PS) and lower reserve levels (PT); in mixing in said stations (6) volumes of materials taken from the loaded silos (8) in order to obtain materials having presettable characteristics; and in feeding said user machines (7) with said materials having the preset characteristics.

Inventors: TAROZZI FAUSTO, TAROZZI, FAUSTO
Applicants: GRUPPO BARBIERI & TAROZZI SRL, GRUPPO BARBIERI & TAROZZI S.R.L.
Application year: 2000
Main classification: B28C9
IPC codes: B28C9, B28C7, B28B15