SIEVE SYSTEM FOR A GRINDING DEVICE, AND GRINDING DEVICE USING THIS TYPE OF SIEVE SYSTEM

Abstract

A sieve system for a grinding device permitting the processing of materials in terms of particle size, in particular the processing of solid or powder materials. The system includes a filtering portion having fine holes and designed to cooperate with a rotor of the grinding device in such a way as to press the material to be ground through said filtering portion; and a support portion having large holes, which is able to reinforce the filtering portion. The sieve can be coupled to a vibratory device. The sieve system allows for the grinding method to be operated in continuous mode, with a material flow rate through the sieve up to 50% higher than that reached with a conventional sieve.

Claims

1. Sieve system for a grinding device, comprising: a filtering portion having fine holes and designed to cooperate with a rotor of the grinding device in such a way as to press the material to be ground through said filtering portion); and a support portion enabling the filtering portion to be reinforced, wherein the support portion is provided with openings comprising the elements of the filtering portion; the filtering portion being integral with the support part.

2. Sieve system according to claim 1, wherein the filter portion and the support part are made of a metal alloy.

3. Sieve system according to claim 1, wherein the support is constituted by a surface provided with a plurality of openings, each provided with a filtration zone having openings adapted to this function.

4. Sieve system according to claim 1 being connected by a connector ring to a vibration generator facilitating the continuous flow of powder materials through the filtering portion.

5. Grinding device comprising a sieve system comprising a filtering portion having fine holes and designed to cooperate with a rotor of the grinding device in such a way as to press the material to be ground through said filtering portion, a support portion enabling the filtering portion to be reinforced; the support portion being provided with openings comprising the elements of the filtering portion; the filtering portion being integral with the support part.

6. Method of manufacturing the sieve system comprising a filtering portion having fine holes and designed to cooperate with a rotor of a grinding device in such a way as to press the material to be ground through said filtering portion, a support portion enabling the filtering portion to be reinforced; the support portion being provided with openings comprising the elements of the filtering portion; the filtering portion being integral with the support part; the method comprising the steps of applying masks respectively sized for the support part and the filter portion to a raw plate and placing the raw plate with masks in a chemical bath.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Exemplary embodiments of the invention are indicated in the description illustrated by the attached figures in which:

[0030] FIG. 1 is a view of the plate forming the sieve, after perforation of the multiple openings and delimitation of the support;

[0031] FIG. 2 is a perspective view of a part of the single-piece sieve included in a grinding device, according to one embodiment;

[0032] FIG. 3 is a sectional view of a sieve system included in a grinding device according to another embodiment; and

[0033] FIG. 4 is a perspective view of the functional assembly of the grinding device comprising the sieve system outside the enclosure of the grinding device, according to another embodiment.

EXAMPLE(S) OF EMBODIMENTS OF THE INVENTION

[0034] FIG. 1 illustrates an exemplary embodiment of a sieve 1 for a grinding device, in a perspective view where the sieve is shown flat. The single-piece sieve 1 is made of a metal alloy material, composed of a filtering portion 6 and a support part 5 arranged to form in a single block. The support part 5 is provided with large openings 3 in which the elements of the filtering portion 6 are shown. The support part constitutes a thick and solid element, providing the sieve 1 with a certain rigidity. The filtering portion 6 is composed of fine openings 4 in order to facilitate a fluid flow of material flow. Such a single-piece sieve arrangement 1 makes it possible, as opposed to prior sieves consisting of several glued or welded elements, to prevent the powder materials from being able to slip into cavities which do not exist in this architecture. The shapes and dimensions specific to the different openings of the single-piece sieve are here represented in circular form; however, the rounded form is not exhaustive since a multitude of shapes can be envisaged to fulfill the same function.

[0035] FIG. 2 is a perspective view of a part of the single-piece sieve 1 included in a grinding device 10 of the hammer grinder type. in the illustrated example, the grinding device 10 comprises an enclosure 11 which defines a grinding chamber 16 which can be filled with the material to be ground, a rotor assembly 14 rotatably mounted in the enclosure 11, and a sieve 1 to split the crushed material by the rotor assembly 14, which moves and unfolds below the rotor assembly 14. A driver unit 20 is designed to control the movements of the rotor assembly 14 relative to the sieve 1 during the grinding operation.

[0036] FIG. 3 illustrates another example of a grinding device 10 as a whole, in this case a conical sieve type shown in section, using a single-piece sieve 1 as described above. This system is integrated in a tubular protective housing 11 defining the grinding chamber 16 and wherein the sieve 1 is mounted coaxially. The sieve 1 is a truncated cone shape which tapers downwards. A rotor assembly 14 is rotatably mounted in the sieve 1. In the configuration illustrated in FIG. 3, the rotor 14 comprises two symmetrical grinding blades 141 arranged so that the space between each blade 141 and the sieve is essentially constant. During a grinding operation, the rotor 14 rotates relative to the inner wall of the sieve 1 so as to press the grinding material from the top of the chamber 16 against the sieve 1 and pass it through the openings 4 of the sieve 1.

[0037] The protective enclosure 11 enables the functional assembly of a powder material grinding system to be arranged in a closed and protected environment so that the grinding process can be carried out under specifically controlled conditions. In the example illustrated, the enclosure 11 is delimited by a wall 13 whose dimensions are adapted as a function of the volume required to accommodate the functional assembly of the grinding system.

[0038] The single-piece sieve 1 shown in the various figures, at various angles, is a single-piece sieve 1 made of a metal alloy. This single-piece element is obtained by a specific manufacturing process by chemical machining which is opposed to the sieve manufacturing process known in the prior art.

[0039] The manufacture of the single-piece sieve is made possible by chemical machining. A raw plate is immersed in a chemical bath. Different masks are used on both sides of the plate. The depths of the perforations are then precisely managed in order to obtain a filtrating part 6 with fine openings on one side 4 and a support part 5 with wide openings 3 on the other.

[0040] In one embodiment, the single-piece sieve 1 is coupled to a vibration generator 7 by means of a connector ring 12 surrounding the sieve 1. Such a configuration has the effect of facilitating the flow of the ground material through the sieve 1. The effect of the vibration makes it possible to prevent the material from agglomerating in the openings 4 of the sieve 1 during the grinding operation, thus allowing a continuous flow of the ground material without human intervention. Indeed, the vibrations generated by the vibration generator 7 are transmitted to the filtering portion of the sieve 6 very efficiently. This results in an acceleration of the circulation of the ground material, in particular by avoiding the risk of stagnation of the powder materials. The single-piece architecture also prevents the sieve from becoming fragile through the vibrations exerted since the latter is devoid of any bonding or welding zones.

[0041] In the examples illustrated in FIGS. 2 and 3, the vibration generator 7 is coupled to the connector ring 12 via a vibration-conducting arm 9 and an adapter 8, or connector. FIG. 4 is a perspective view of the same grinding system as that of FIG. 3, but in which the elements inside the protective enclosure 11 are shown outside it, in order to visualize more precisely certain functional elements of the vibration chain, and in particular the vibration transmitting ring 12.

[0042] The coupling of the vibration generator 7 to the sieve 1 can be ensured by a configuration other than that of the connector ring 12 illustrated in FIGS. 2 and 4. For example, the vibration generator 7 can be coupled directly to the support part 5 of the sieve 1. In FIG. 3, the vibration generator 7 is coupled to the sieve 1 by means of an arc 12 disposed at one end of the sieve 1 of cylindrical shape.

[0043] The chamber 11 not only permits grinding of powder materials in a healthy and opaque environment but also serves to collect the powder materials which have passed through the single-piece sieve 1. The system for grinding powder materials by means of grinding thus permits a continuous treatment of the materials without human intervention, by virtue of the combination between the single-piece screen 1 and the vibration device 7, 8, 9. The dimensions of the enclosure 11 are also advantageously defined so as to take account of the vibration device connected to the sieve.

[0044] In a grinding process with the sieve system 1 comprising the vibration generator 7, the flow rate of the material through the sieve can be up to 50% higher than the flow achieved by using a sieve comprising two or several parts and in the absence of vibration exerted on the sieve. There is therefore less retention of material in the grinding chamber, thereby improving the efficiency of the grinding operation. Other advantages include the lower temperature generated by the grinding operation and less power to rotate the rotor during the grinding operation.

[0045] The treatment system previously described is advantageously used in the context of a process for treating materials, in particular powder materials, with steps involving mechanical operations carried out on the material, such as, for example, sieving, centrifuging, weighing, sorting, grain-sizing, or other mechanical operation. The process is particularly suitable for powder materials, without excluding other forms of material, for example granulates.

[0046] The figures and their descriptions given above illustrate the invention rather than limit it.

[0047] The references in the claims are not limiting. The verbs to comprise and to include do not exclude the presence of elements other than those listed in the claims. The word one/a(n) preceding an element does not exclude the presence of a plurality of such elements.

REFERENCE NUMBERS USED IN THE FIGURES

[0048] 1 sieve [0049] 10 grinding device [0050] 11 enclosure [0051] 12 ring connector [0052] 13 wall [0053] 14 rotor assembly [0054] 141 grinding blades [0055] 16 grinding chamber [0056] 20 driver unit [0057] 4 openings [0058] 5 support part [0059] 6 filter part [0060] 7 vibration generator [0061] 8 connector [0062] 9 driver arm