GRINDING TOWER DEVICE

Abstract: Grinding device for grinding granulates, in particular plastic granulates, to powder, comprising in successive, mutually downstream arrangement, at least one silo (70) in which the material to be ground is stored, a downstream grinding unit (80) for grinding the material and a collecting unit (90) for collecting the ground material, characterised in that said grinding unit (80) is set up in direct connection with the input silo (70) and substantially vertically underneath it, in such a way that the material to be ground may flow gravitationally from here (70) to the grinding unit (80) on the one hand, and that said collecting unit (90) is set up in direct connection with the grinding unit (80) and substantially vertically underneath it, in such a way that the ground material may flow gravitationally from here (80) to the collecting unit (90) on the other hand.

Description: Grinding tower device Field of the invention The present invention concerns a device for grinding granulates, particularly plastic granulates, to powder for various applications. The overall grinding process can be subdivided into a number of subsequent production steps, consisting of supplying material to an intermediate storage, supplying the material from said intermediate storage to the grinding system, grinding the material, supplying this material to a further intermediate storage and, finally supplying this material from said further intermediate storage to a packaging machine. Each step is carried out by means of a corresponding section of the grinding device. State of the art At present, these subsequent production steps are located on one single level in the height direction, whereby each said section occupies one single level. As a result, after each step carried out within a section, the material must each time be moved upwards, on top of the following section. This means that several lifting systems are needed and thus several interventions of operators are required. These lifting systems are controlled separately and each time run a high risk of malfunctions, especially when the lifting of powders is concerned. The problem which arises when various systems 2 must be brought into action, is that after a product change on the system, which takes place when a product to be ground is replaced by another in it, the risk of contamination is much higher, in particular in the case of powders. Each time, various lifting systems also have to be cleaned. Thus, this gives rise to a problem of reliability in operation and of cleanability of the various lifting systems in the overall grinding system. This activity may be advantageously combined with classical logistic operations on a product, whereby a process specific production activity may be added thereto. The processing processes in which these powders are applied, are all high-grade. It is of importance thereby, that these powders are completely free from contamination with other plastic materials or foreign materials. When the customer of the ground product or the bulk powder wants to receive the latter in unpacked condition, the packaging device must be removed and the powder must be lifted again to above the bulk truck used thereto. This is especially labour-intensive, to which yet a loss of packaging materials must be added. This invention aims at offering a solution to above mentioned problem. For this purpose, the invention is characterised in that all process sections of the overall grinding device are set up on top of each other. Due to this particular arrangement, a much simpler system is obtained. The material consequently has to be lifted only once, after which the material flow finds its way by gravity through the successive processing sections with their respective process steps. Interventions by operators are no longer needed. The advantages obtained in this way thus consist of the fact that only one lifting system is needed in the whole grinding device that is simple to operate. The 3 risk of contamination after a product change is much smaller, because only one lifting system needs to be cleaned. Moreover, this is a lifting system for granulates, which is simpler to clean than a lifting system for powders. Because the intermediate storage of powder occurs in silos, it is also easier to deliver powder in bulk. In this way, a bulk truck may be filled directly under the silo. In this way, a particularly efficient combination is thus obtained for processing granulates by grinding on the one hand, with a logistic operation on the other hand. This activity may also favourably be combined with non-classical logistic operations, such as described in documents BE 9700852 and BE 9700857 respectively. A particularly excellent complementarity may be obtained herewith. Further characteristics and particularities of the device according to the invention are defined in the further dependent claims. Further advantages and details of the device according to the invention will appear from the following description of an example of embodiment of the device according to the invention, which is described by means of the annexed drawings. Concise description of the figures Figure 1 is a schematic representation of a classical system for a grinding device. Figure 2 is an analogous representation to figure 1 , but of a grinding device according to the invention. Description Figure 1 shows that the material to be ground is supplied from a silo 10 or a warehouse to a small intermediate storage 20. From this intermediate storage, the material is moved upwards by means of a blower 21 and a cyclone 22 into the grinding system. 4 In a grinding system 30 the material to be ground is metered. The ground material is collected in a small hopper 41 , and subsequently by means of a further blower 42 and a further cyclone 43, moved upwards to a small supply hopper 51 on top of a packaging machine 50. Subsequently, the ground material is packaged with the packaging machine 50. A major drawback in this is, that the above described packaging system 50 has a much larger capacity than the grinding system 30, and in this way that the packaging machine must necessarily continuously empty the grinding machine. This could be solved by a larger intermediate storage, for example a- silo, to be provided between the grinding system and the packaging system. However, this would have a particularly disadvantageous repercussion on the total surface occupied by the assembly. Another major drawback of the above described system is, that the lifting systems for both the granulate and the powder, are fairly complex and moreover difficult to clean, especially in the latter case. On the other hand, contamination must absolutely not occur. Thus, a serious problem arises. By eliminating these lifting systems as much as possible, this may be remedied. Figure 2 shows a system in which the material to be ground is blown directly from a bulk truck 60 into a storage silo 70. From said silo 70, the material is gravitationally supplied to the grinding system 80. The ground material is directly and gravitationally supplied from the grinding system to a following silo 90 or 90'. The row of silos 90, 90' concerned also serves as a buffer, so that the packaging system 50 needs not te be continuously in operation to empty the grinding system and/or may be used elsewhere. An advantage of the use of a further powder silo 90 consists in that herewith also direct bulk loading 100 is possible to a bulk truck 106 for transport.

Claims: 6 CLAIMS 1. Grinding device for grinding granulates, in particular plastic granulates, to powder, comprising in successive, mutually downstream arrangement, at least one silo (70) in which the material to be ground is stored, a downstream grinding unit (80) for grinding the material and a collecting unit (90, 90') for collecting the ground material, characterised in that said grinding unit (80) is set up in direct connection with the input silo (70) and substantially vertically underneath it, in such a way that the material to be ground may flow gravitationally from here (70) to the grinding unit (80) on the one hand, and that said collecting unit (90, 90') is set up in direct connection with the grinding unit (80) and substantially vertically underneath it, in such a way that the ground material may flow gravitationally from here (80) to the collecting unit (90, 90') on the other hand. 2. Grinding device according to claim 1, characterised in that a lifting unit (61 ) is provided for moving upwards the material to be ground directly from a bulk truck (60) to said upward storage silo (70). 3. Grinding device according to claims 1 or 2, characterised in that the outlet (91') of the downstream silo (90') is put into connection with a packaging apparatus (50) for packaging the ground material. 4. Grinding device according to claims 1 or 2, characterised in that the outlet (91 ) of the downstream silo (90) is put into connection with a transport unit (62) for delivering the ground material in bulk. 5. Device for shipping bulk products comprising: - a storage space for said bulk products consisting of a silo battery, and - a shipping space provided downstream from said storage space, 7 whereby said shipping space is substantially completely sealed by an enclosure, and whereby said bulk products, which follow a flow direction (F), are processed to a transportable and dischargeable form, characterised in that said shipping space shows an intermediate level which is arranged substantially parallel to the ground on which the silo battery is located and that divides said shipping space in two partial spaces, whereby the one forms an upstream partial space in which the discharge outlets of the silos directly open into, whereas the other forms a downstream partial space, which is substantially completely sealed from said discharge outlets of the silos, whereby if is located downstream from the said one, that said one, upstream partial space is provided for an in situ packaging of said bulk products to packaging units, the volume and/or the weight of which is adjustable, by means of a packaging means provided thereto, whereas said other, downstream partial space is provided for a shipping of the bulk product to a further transport unit for bulk goods in unpacked condition, that both said partial spaces are mutually connected by means of communication means provided thereto, and whereby a grinding device according to any one of the preceding claims is incorporated herein. 6. Device for shipping bulk products comprising: - a storage space for said bulk products consisting of a silo battery, and - a shipping space provided downstream from said storage space, whereby said shipping space is substantially completely sealed by an enclosure and whereby said bulk products, which follow a flow direction (F), are processed to a transportable and dischargeable form, characterised in 8 that said shipping space is installed onto the ground itself on which the silo battery is located, and that said shipping space is each time divided in two partial spaces in which the discharge outlets of the silos directly debouch, that said one partial space is provided for an in situ packaging of said bulk products to packaging units, the volume and/or the weight of which is adjustable, by means of a packaging means provided thereto, whereas said other partial space is provided for a shipping of the bulk product to a further transport unit for bulk goods in unpackaged condition, that both said partial spaces are mutually separated by 'means of a separation means provided thereto, and that a movable means of connection is provided to connect said discharge outlets of each silo to the desired partial space such that the partial space selected in this way is activated, and whereby a grinding device according to any one of claims 1 through 4 is incoφorated herein.

Inventors: LEROY FABIAN, LEROY, FABIAN
Applicants: LEROY FABIAN, POLYMER PROCESSING RES INST, LEROY, FABIAN, POLYMER PROCESSING
Application year: 1998
Main classification: B02C21
IPC codes: B02C21, B29B13