EP1862220A1

EP1862220A1 - Mill for the grinding of minerals

Info

Publication number: EP1862220A1
Application number: EP07109396A
Authority: EP
Inventors: Maximo Fernandez Coronado
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-06-01
Filing date: 2007-06-01
Publication date: 2007-12-05
Also published as: ES1063091U; ES1063091Y

Abstract

Mill for the grinding of minerals of the type made up of a grinding chamber fitted with an opening through which the minerals enter and another for their outlet, the walls of which are lined with several robust teeth against which the minerals to be ground are projected by means of a rotor that rotates inside, characterised by having an adjustable sizing screen fitted to the outlet opening of the grinding chamber to select the granulometry of the ground fragments.

Description

OBJECT OF THE INVENTION

The present invention refers to a mill for the grinding of minerals, such as stones and aggregates in general, in order to reduce them to a suitable size for their use as construction material, such as gravel, coarse aggregate or to obtain cements, concretes and such like.
The object of the invention focuses on fitting means to select the granulometry, that is to say, the size of grain in the final ground product.

BACKGROUND OF THE INVENTION

On the market, there are already mills for the grinding of minerals, basically intended for the construction sector, made up of a chamber whose inner walls are lined with a number of robust teeth, against which the minerals to be ground are projected by means of a rotor that rotates inside. The above-mentioned grinding chamber has an inlet opening, generally at the top, which the minerals enter through for their crushing and grinding by being projected against the inner walls, and by the rotation of the rotor blades that traps them against the teeth in the walls.
These mills have an outlet opening at the bottom of the grinding chamber, out of which the ground minerals fall.
Since the ground minerals are freely expelled by the force of gravity through the bottom opening, the granulometry of the final product is very different and a later classification process is needed to be carried out in order to grind the fragments that are too large and unsuitable for the use in question again.
Another disadvantage of this type of mills is that they do not allow small mineral fragments below a specific granulometry to be ground, since they are expelled through the outlet opening of the chamber without being crushed, due precisely to their restricted size. This leads to waste quantities of ground material with excessive granulometry, unsuitable for use in the construction sector.

DESCRIPTION OF THE INVENTION

The mill for the grinding of minerals proposed by the invention solves the aforementioned problem by fitting means to select the granulometry, that is to say, the size of grain in the final ground product.
To this end, and in a more concrete way, the mill for the grinding of minerals is that of the type made up of a grinding chamber fitted with an opening through which the minerals enter and another for their outlet, the walls of which are lined with several robust teeth against which the minerals to be ground are projected by means of a rotor that rotates inside, having an adjustable sizing screen fitted to the outlet of the grinding chamber to select the granulometry of the ground fragments.
The aforementioned sizing screen is made up of a number of parallel metallic bars fitted to a set of guides with corresponding pipe grooves into which the bars are inserted.
Another possibility is that the sizing screen is made up of a metallic plate fitted with a number of openings with the same diameter, placed on a removable fastening guide.
As much in one case as the other, the fastening guide shall have a curvilinear shape following the grinding chamber's enveloping casing.
Where metallic bars are used, they shall be conically embodied so that the outlet holes are approximately parallel.
To select the granulometry of the final product, we only have to replace the metallic bars that make up the sizing screen by others with a different width, to increase or reduce the outlet opening of the screen. Where using a perforated metallic plate, it shall be replaced by another one fitted with openings of another diameter.

DESCRIPTION OF THE DRAWINGS

To complete the description that is being given and in order to help give a better understanding of the invention's characteristics, with the idea to provide an essential example of its practical undertaking, a set of drawings with an illustrative, non-restrictive character is attached as an integral part of the aforementioned description, showing the following:

Figure 1 shows a properly divided vertical section of the mill aimed at in the invention, where the inside of the grinding chamber, the rotor and arrangement of the sizing screen fitted to the outlet opening may be seen.
Figure 2 shows a detailed plant view of the sizing screen made up of metallic bars fitted to the guides.
Figure 3 shows a vertical section of the sizing screen shown in the previous figure.
Figure 4 shows a vertical section of the metallic bars that make up the sizing screen.

PREFERRED EMBODIMENT OF THE INVENTION

In view of the outlined figures, it may be seen that the mill for the grinding of minerals is of the type comprising a grinding chamber 1, fitted with an opening 2 through which the minerals to be ground enter and an outlet opening 3 to eject them once ground. The inside of the grinding chamber 1 is lined with a number of robust teeth 4, known as "palate", against which the minerals are projected and then ground by means of a rotor 5 that rotates inside the chamber.
To select the granulometry of the ground mineral, a sizing screen 6, made up of a number of parallel metallic bars 7, is fitted to the outlet opening 3.
The fastening of these metallic bars 7 is carried out by way of a set of guides 8, which have a curvilinear shape following the grinding chamber's enveloping casing. The aforementioned guide 8 is fitted with a number of grooves 9 into which the metallic bars 7 are inserted through slots 10 made at their ends. So that the opening defined between the consecutive metallic bars 7 is approximately parallel, a conical embodiment design has been used.
Due to the arrangement of the guides 8, we may replace the metallic bars 7 by others with a different width to increase or reduce the screen's outlet opening.
Another embodiment of the sizing screen 6 consists of using a perforated metallic plate, not shown in the drawings, at the outlet opening 3, which has the same curvilinear shape as the guides 8. In this case, to select the granulometry of the ground mineral, the perforated plate is replaced by another one having openings of a different diameter.
Thus, due to the sizing screen 6 fitted to the outlet opening 3, the mill shall eject the ground minerals whose size is less than the opening of the sizing screen. The rest of the larger fragments shall continue rotating inside the grinding chamber 1, driven by the blades 11 of the rotor 5, to be ground again in the following laps until their size is less than that of the screen's opening 6, at which moment they will be ejected from the grinding chamber.
In the design, the sizing screen 6 is fitted to the outlet opening 3 and has a curvilinear shape following the grinding chamber's enveloping casing, so that the fragments smaller than the opening of the screen continue their next circular lap inside the grinding chamber 1, without causing undesired blocking or accumulation.

Claims

Mill for the grinding of minerals of the type made up of a grinding chamber fitted with an opening through which the minerals enter and another for their outlet, the walls of which are lined with several robust teeth against which the minerals to be ground are projected by means of a rotor that rotates inside, characterised by having an adjustable sizing screen fitted to the outlet opening of the grinding chamber to select the granulometry of the ground fragments.
Mill for the grinding of minerals, according to claim 1, characterised by the sizing screen being made up of a number of parallel metallic bars fitted to a set of guides with corresponding pipe grooves into which the bars are inserted.
Mill for the grinding of minerals, according to claim 1, characterised by the sizing screen being made up of a metallic plate with a number of holes of the same diameter fitted to a removable fastening guide.
Mill for the grinding of minerals, according to claim 2, characterized by the metallic bars having a conical embodiment.
Mill for the grinding of minerals, according to claims 2 and 3, characterised by the fastening guides having a curvilinear shape following the grinding chamber's enveloping casing.