MX2007008602A

MX2007008602A - A connecting system between continous mills in series in a grinding plant.

Info

Publication number: MX2007008602A
Application number: MX2007008602A
Authority: MX
Inventors: Simone Casadio; Pierre Poli
Original assignee: Sacmi
Priority date: 2006-07-20
Filing date: 2007-07-16
Publication date: 2009-01-07
Also published as: PL1880767T3; RU2007121939A; EP1880767A1; RU2474476C2; PT1880767E; ITRE20060089A1; CN101108371A; BRPI0702972A; ES2351857T3; EP1880767B1; CN101108371B

Abstract

A grinding plant (1), comprising a plurality of continuous mills (2) each provided with a loading mouth (6) of raw material and an unloading mouth (8) of slip, which loading mouth (6) and unloading mouth (8) are placed in series by means of a connecting element (19), which connecting element (19) is associated to an in-loading device (20, 21) and connects the unloading mouth (8) of a mill to the loading mouth (6) of a contiguous mill. Associated to the connecting element (19) are means for preventing exiting of the material from the connecting element (19) during advancing of the material from a mill which is upstream to a mill which is downstream.

Description

CONNECTION SYSTEM BETWEEN CONTINUOUS MILLS IN SERIES IN A GRINDING PLANT TECHNICAL FIELD The present invention relates in a general sense to a grinding plant intended in particular, although not exclusively, to be used in the preparation of ceramic mixtures. These mixtures are usually prepared by wet pulverization of the raw materials (silicon, feldspars, clay) and the addition of specific additives, until a homogeneous paste having the desired granulometry of the suspended powders is obtained. As is known, a plant of this type usually comprises at least one grinding mill, which is provided with a rotating cylinder, internally from which the process of spraying the raw materials by impact takes place, and in any case by reciprocal action, between the raw materials themselves and a number of crushing bodies usually spherical. Known crushing mills are subdivided into continuous mills and discontinuous mills, depending on whether the stage of loading the raw materials into the cylinder and the stage of unloading the pulp are carried out continuously during the operation of the mill, or discontinuously, requiring the temporary interruption of the production process and the stopping of the rotating cylinder.

The present invention relates in particular to a grinding plant comprising continuous mills. In the prior art in the ceramics sector, the pulverization of raw materials comprises a process in successive stages, starting from a breaking stage and ending with a refining step. In the various stages, the grinding bodies exhibit different sizes, which progressively decrease in order of stages from the break to the refining; consequently, for each of the stages there is a rotational speed of the rotating cylinder such as to optimize the labor operation, the labor times and the power consumption of the grinding mill. For these reasons, the prior art describes plants comprising a plurality of continuous crushing mills arranged in series, in which the rotating cylinder of each mill contains crushing bodies and rotates at a speed independent of the others, to carry out a of the stages described above of the continuous process optimally. A similar plant is described in detail in Italian Patent Application RE2003A000013, by the present Applicant, to this patent application reference should be made for additional details. In particular, each rotating cylinder of the plant described above is provided with a loading orifice for the material to be worked and a discharge orifice for the paste, the holes are arranged on opposite sides of the cylinder and are arranged along the axis of rotation thereof, and the orifices rotate solidly with the cylinder, facilitating the continuous advancement of the raw material being loaded and the paste being discharged . In addition, the discharge orifice of an intermediate rotating cylinder is connected to the loading orifice of the next cylinder, by means of a tubular connecting element, which is also associated with a loading device for introducing crushing bodies and special aditives (for example, dyes) directly internally of the downstream cylinder. A disadvantage of these known plants is that the tubular connection element, differently to the discharge and charge conduits which rotate solidly with the respective rotating cylinders, must be solidly connected to the loading device and, consequently, must be fixed. In fact, the free end of the discharge orifice is inserted axially by a section thereof internally of the tubular connection, which in turn is inserted by a section thereof internally of the free end of the loading orifice of the next mill. With this configuration the material advancing between a rotating cylinder and a next rotary cylinder exhibits the tendency to fall accidentally from the interface side between the rotating cylinder upstream and the tubular connection and from the interface side between the tubular connection and the rotating cylinder located downstream. This is due to the fact that the granular and abrasive nature of the pulp makes it difficult to make suitable sealing devices. The object of the present invention is to obviate the disadvantage mentioned above, by providing a solution that is simple, rational and cheap. The object is reached by a continuous grinding plant comprising a plurality of continuous mills arranged in series, in which the discharge orifice of a mill and the loading orifice of the next mill are connected by a connecting element, means are provided to prevent the exit of the material mentioned above between the connecting element (19) and the loading orifice and the discharge orifice during the advance of the material from the mill upstream to the downstream mill. In a preferred embodiment of the invention, the means comprise a first helical body fixed to the free end of the discharge hole of the mill upstream, such that the first helical body mentioned above is inserted internally of the connecting element, performing, in collaboration with a part of the internal surface of the connecting element, a first screw device that, during the advance of the material, maintains the material internally of the connecting element.

The means preferably further comprise a second helical body located in the mill loading hole downstream and fixed internally thereto, the second helical body is internally inserted from the downstream mill loading orifice and made, in collaboration with the orifice of the mill. load of the mill downstream, a second screw device that prevents the material from the end downstream of the connection element. The additional features and advantages of the invention will emerge from a reading of the following description, provided purely by way of non-limiting example with the help of the attached figures of the drawings, in which: - Figure 1 is a schematic view of the continuous crushing plant of the invention; - Figure 2 is a detail of the connection system between the mills of the invention. With reference to the Figures of the Drawings, the grinding plant of the present invention, denoted entirely by 1, comprises a plurality of continuous mills 2 arranged in series. Each mill 2 comprises a rotating cylinder 3, which is formed by a cylindrical body 4 having a horizontal axis, the body 4 is closed, at one end thereof, by a first base 5 provided with an axial hole 6 for loading the material, and at an opposite end thereof, by a base 7 provided with an axial hole 8 for discharging the paste. The rotary cylinder 3 is supported at each end by a suitable structure 9 and is activated by a special control system 10 by means of a band system 1 1. Internally of the rotating cylinder 3 there is a crushing chamber, internally from which both the grinding bodies and the raw materials constituting the paste are supplied, that is, essentially water, silicon, feldspars, clay. The grinding bodies are usually made of silicon or aluminum and during the operation of the plant they wear out, to the point that they are mixed with the paste under processing. Figure 1 shows that the first upstream mill 2 is provided with a conventional loading system 18 of the raw materials, which is itself known, and that the loading orifice 6 of the second mill, and any additional mills, are connected both to the discharge orifice 8 of the preceding mill and to a loading conduit 20 which is associated with an additional loading device 21. The loading duct 20 advantageously allows the grinding bodies to be added separately for each of the continuous mills 2, and also allows materials or water to be introduced separately, thus constantly allowing the mixture to be corrected and ensuring an optimum composition.

Each of the continuous mills 2 of the crushing plant 1, being operatively independent of the others, is of optimum size and is also optimized in terms of the geometry thereof, the dimensions of the grinding bodies and the rotation speed, for the specific spraying step to be carried out, and the pulp under process passes continuously from a rotating cylinder 3 to a next rotary cylinder 3 without interruption of the process, until the desired granulometry of the suspended powders is obtained. The evacuation of the refined paste from the operating chamber of a rotating cylinder 3 is carried out by conventional means of known type which are not further described herein. However, for the purposes of understanding the present invention, it is emphasized that although the means for evacuating advance the pulp towards the rotating cylinder 3 located downstream, this advancement is also realized, and becomes efficient, by the rotation of the orifice 8. of discharge and the loading orifice 6, which are solidly restricted to the respective rotary cylinders 3. As previously mentioned, a fixed tubular connection element 19 is interposed between the discharge orifices 8 and the loading orifices 6, the connection element 19 is constituted substantially by a tube fixed to the support structure 9 by means of a support 25 rigid.

The following are rotatably associated with the fixed tubular connecting element 1 9: on one side thereof, the discharge orifice 8 and on the other side thereof, the loading orifice 6. In detail, the free end of the discharge orifice 8 is inserted axially, by a section thereof, internally of the tubular connection element 1 9, which in turn is inserted, by a section thereof, internally of the free end of the orifice 6. of cargo. The discharge orifice 8 is thus smaller than the fixed connection element 19, while the connection element 19 is smaller than the loading orifice 6. Suitable means for sealing can be interposed between the discharge orifice 8 and the loading orifice 6 and the tubular connection element 19, the sealing means can advantageously contribute to preventing the leakage of material from the plant 1. In particular, as can be seen in Figure 2, a first helical body 23 is fixed to the free end of the discharge orifice 8 and to the external surface thereof, making a first screw device according to the invention. In this way the first helical body 23 is rotated by the rotation of the continuous mill 2, to which the discharge orifice 8 is associated. In addition, a second helical body 24 is fixed internally of the loading orifice 6 downstream of the mill, realizing a second screw device of the invention.

Similar to the first helical body 23, the second helical body 24 is rotated by the rotation of the continuous mill 2, to which the loading orifice 6 is associated. During the operation of the plant 1, the rotary cylinders 3 rotate independently of each other and, consequently, move the discharge orifice 8 and the loading orifice 6 in rotation, while the tubular connection element 19 remains fixed. In this way the first helical body 23, which is connected to the discharge orifice 8, rotates internally of a first portion of the connection element 19. The first helical body 23, during the advance of the material, cooperates with the internal surface of the connection element 19 and forms a first screw device that has the function of maintaining the material itself internally of the connection element 19, also preventing the material accidentally exit the upstream end of the tubular connection element 19. In addition, the second helical body 24, which is connected to the loading orifice 6, rotates internally of the loading orifice 6 and, in cooperation with the external surface of the connecting element 19, forms a second screw device that effectively contributes to preventing the material outlet from the downstream end of the tubular connection element 19.

The properties of the present invention are advantageous also in consideration of the fact that another material flows internally from the connecting element 19 through the loading pipe 1 0. Obviously modifications or improvements, dictated by requirements or contingent details, can be made to the plant as described without leaving the scope of the invention as claimed herein below.

Claims

1. Crushing plant, comprising a plurality of continuous mills, each provided with a raw material loading orifice and a paste discharge orifice, the loading orifice and the discharge orifice are placed in series by means of an element of connection, the connection element is associated with a loading device and connects the discharge orifice of a mill to the loading orifice of a neighboring mill, characterized in that associated with the connection element are means for preventing the exit of the material from the connection element in the discharge orifice and the loading orifice during the advance of the material from a mill that is upstream to a mill that is downstream.

2. Plant according to claim 1, wherein the means for preventing the exit of the material comprise at least a first helical body associated with a free end of the discharge hole of the mill upstream, in which the first helical body is inserted into the element of connection, carrying out, in collaboration with the connecting element, a first screw device that during the advance of the material maintains the material inside the connection element.

3. Plant according to claim 1 or 2, wherein the means for preventing the exit of the material comprise a second helical body that is associated with a free end of the loading hole of the mill downstream, in which the second helical body is inserted internally in the loading hole of the downstream mill, performing, in collaboration with the loading orifice, a second screw device which prevents the material from leaving the downstream end of the connecting element.

4. Plant according to claim 2, wherein the first helical body is fixed externally on the discharge orifice, such as to be rotated by the rotation of the continuous mill to which the discharge orifice is associated.

5. Plant according to claim 3, wherein the second helical body is fixed internally on the loading orifice, such as to be rotated by the rotation of the continuous mill to which the loading orifice is associated.

6. Plant according to claim 1, wherein the loading device comprises a device for loading the material, and a charging duct connecting the charging device to the connecting element.

7. Plant according to claim 1, wherein the means for sealing are interposed between each of the discharge orifices and the loading orifices and the connecting element.