WO2015008207A2

WO2015008207A2 - Plant for the granulation of loose material

Info

Publication number: WO2015008207A2
Application number: PCT/IB2014/063080
Authority: WO
Inventors: Umberto Manfredini
Original assignee: Manfredini E Schianchi S.R.L.
Priority date: 2013-07-19
Filing date: 2014-07-14
Publication date: 2015-01-22
Also published as: WO2015008207A3; ITMO20130209A1

Abstract

The plant (1) for the granulation of loose material comprises granulating machine (2) having an inner chamber with an inlet mouth (2a) of a loose material to be granulated and an outlet mouth (2b) of a granulated material and able to dispense a fluid within the chamber and to mix the loose material and the fluid to obtain the granulated material, wherein the granulating machine (2) comprises detection means (3) able to detect the humidity value of the loose material and regulation means (4) able to regulate the amount of fluid introduced into the chamber depending on the detected humidity of the loose material, and in that said plant (1) comprises suction means (5) arranged downstream of the granulating machine (2) and able to separate any fine powders from the granulated material coming from the outlet mouth (2b) and to move the fine powders towards the inlet mouth (2a) of the granulating machine (2), for the reuse of the powders themselves, wherein the regulation means (4) and the suction means (5) reduce the percentage of added fluid, by eliminating the need to employ a drying system.

Description

PLANT FOR THE GRANULATION OF LOOSE MATERIAL

Technical Field

The present invention relates to a plant for the granulation of loose material. Background Art

In the production of raw materials for ceramic products, with particular reference to the so-called dry grinding, the use is known of granulation plants having wetting machines able to obtain a loose material consisting of spherical particles of a predefined size, precisely called "granulate".

The wetting machines of known type generally comprise a bearing structure having a processing chamber for the loose material to be humidified.

An upper mouth allows the loose material to entry by fall within the processing chamber and below this mouth a cone is suitably arranged for the distribution of loose material within the processing chamber.

Within the processing chamber and below the cone are arranged one or more concentric rotating disks, moved by a motor and able to spray water at inlet for mixing with the loose material to be humidified.

In practice, the incoming water falls on the disks and, due to the rotation of these, is distributed in a circle directly on the loose material that, once introduced through the upper mouth, falls from the cone.

On the bottom of the processing chamber are a series of steel rotating blades, driven by an independent motor and able to mix the humidified loose material in order to achieve a greater homogenization.

A lower mouth on the processing chamber then allows the output of the humidified material to be moved towards the later processing stages, such as pressing or extrusion.

In such wetting machines the amount of incoming water is adjustable manually or automatically and is directly proportional to the quantity of incoming loose material.

One of the characteristics of traditional granulation plants is to add considerable percentages of water to obtain an acceptable amount of spherical particles.

This makes essential the use of a drying system to reduce humidity up to the one suitable for pressing, as well as of a screening system to eliminate significant amounts of granules of large size, with the consequent increasing of the plant complexity, thus reducing its efficiency.

In addition, the final powder has excessive variations in particle size, i.e. extremely granulated and wet particles, mixed with fine and dried powders, giving rise to serious problems of flowability in the filling stage of the mold cavity.

The wrong particle size distribution of powder also creates the so-called "cracking" defect due to the large granules that prevent the evaporation of water in a constant way, thus forcing to reduce the speed during drying and firing. To this are added the problems in the glazing stage where surface blemishes occur due to poor integration of coarse particles with the thin ones in the support.

These drawbacks are partly overcome by the use of a wetting machine as described in the document no. IT 1 389 917.

In particular, this document describes a machine for humidifying loose material comprising a bearing structure, a humidifying chamber supported by the bearing structure and having an inlet mouth for the loose material to be humidified and an outlet mouth of the humidified loose material, dispensing means for dispensing a fluid within the humidifying chamber of the loose material and mixing means for mixing the loose material and the fluid within the chamber. The machine has detection means for detecting the humidity value of the loose material, humidified or to be humidified, and regulation means associated with the detection means of the humidity value and with the dispensing means of the fluid and able to regulate the amount of fluid introduced into the chamber depending on the detected humidity of the loose material, humidified or to be humidified.

Moreover, the machine comprises distribution means of the powders within the chamber, prior to humidification by means of the fluid, consisting of a rotating element, rotatable due to the action of motor means and arranged within the chamber, below the inlet mouth, and of a diffuser element, arranged below the rotating element and consisting of a cone with a vertical axis and apex turned upwards. In particular, the presence of the regulation means for regulating the amount of fluid introduced allows to improve the humidity control of the humidified loose material, resulting in a more effective and suitable agglomeration of the loose material for next processing stages.

Moreover, the presence of the distribution means, in particular of the rotating element, allows for a better distribution of the loose material within the machine, prior to humidification.

Even this solution of known type, however, is susceptible of upgrading, aimed in particular at significantly reducing the percentage of added water, thereby eliminating the need to employ a drying system to reduce the humidity content up to the desired one.

Description of the Invention

The main aim of the present invention is to provide a plant for the granulation of loose material that allows to significantly reduce the percentage of added water during the humidification stage, thus eliminating the need to employ a drying system.

Another object of the present invention is to provide a plant for the granulation of loose material that allows to limit excessive variations in particle size of the granulate, minimizing the presence of extremely granulated and wet particles and of fine and dried powders.

Another object of the present invention is to provide a plant for the granulation of loose material which can overcome the above mentioned drawbacks of the prior art in the ambit of a simple, rational, easy and effective to use as well as low cost solution.

The above mentioned objects are achieved by the present plant for the granulation of loose material, comprising at least a granulating machine having at least an inner chamber with at least an inlet mouth of a loose material to be granulated and at least an outlet mouth of a granulated material, said granulating machine being able to dispense a fluid within said chamber and to mix the loose material and the fluid to obtain the granulated material, characterized in that said granulating machine comprises detection means able to detect the humidity value of the loose material and regulation means able to regulate the amount of fluid introduced into said chamber depending on the detected humidity of the loose material, and in that said plant comprises suction means arranged downstream of said granulating machine and able to separate any fine powders from the granulated material coming from said outlet mouth and to move the fine powders towards said inlet mouth of the granulating machine, for the reuse of the powders themselves, wherein said regulation means and said suction means reduce the percentage of added fluid, by eliminating the need to employ a drying system.

Brief Description of the Drawings

Other characteristics and advantages of the present invention will become better evident from the description of a preferred, but not exclusive, embodiment of a plant for the granulation of loose material, illustrated by way of an indicative, but not limitative example in the accompanying drawings, in which:

Figure 1 is a general diagram of the plant according to the invention;

Figure 2 is a table showing a possible particle size of the granulated powders obtained by means of the plant according to the invention.

Embodiments of the Invention

With particular reference to such figures, globally indicated by reference number 1 is a plant for the granulation of loose material, usable in particular in the production of raw materials for ceramic products.

The plant 1 comprises a granulating machine 2 having an inner wetting and granulation chamber.

In particular, the inner chamber has an inlet mouth 2a of a loose material to be granulated and an outlet mouth 2b of a granulated material.

The granulating machine 2 also comprises dispensing means able to dispense a fluid within the chamber and mixing means able to mix the loose material and the fluid within the chamber to obtain the granulated material, according to the desired particle size.

Advantageously, the granulating machine 2 comprises detection means 3 able to detect the humidity value of the loose material and regulation means 4 associated with the detection means and with the dispensing means and able to regulate the amount of fluid introduced into the chamber depending on the detected humidity of the loose material.

By so doing, it is possible to maintain a low humidity content of the granulated material coming out of the granulating machine 2.

In particular, the humidity content of the granulated material is between 5% and 10%.

Preferably, the granulating machine 2 is made as claimed and described in the patent document no. IT 1 389 917.

Advantageously, the plant 1 comprises suction means 5 arranged downstream of the granulating machine 2 and able to separate any fine powders from the granulated material coming from the outlet mouth 2b and to move the fine powders towards the inlet mouth 2a of the granulating machine 2, for the reuse of the fine powders themselves.

It should be noticed that in the present description by the words "fine powders" is meant all the granulated material coming out of the granulating machine 2, which has a particle size less than the desired one and that, therefore, may compromise the quality of the ceramic products thus obtained.

The suction means 5 comprise an air sorter 6 arranged downstream of the granulating machine 2 and able to separate the fine powders from the granulated material coming from the outlet mouth 2b.

The suction means 5 also comprise pneumatic transport means 7 connected to the air sorter 6 and able to transport the fine powders upstream of the granulating machine 2, for the reuse of the powders themselves.

Advantageously, the use of the suction means 5, i.e. means able to separate and move the fine powders through the use of air, allows to reduce the percentage of humidity content of the powders themselves during transport towards the granulating machine 2.

Therefore, the use of the granulating machine 2, together with the use of the suction means, allows to maintain low humidity levels of the granulated material, greatly reducing the percentage of water added during the humidification stage and eliminating the need to employ a drying system of the granulate itself.

With particular reference to the embodiment illustrated in the figures, the plant 1 comprises feeding means 8 of the loose material to be granulated associated with the inlet mouth 2a of the granulating machine 2.

In particular, the feeding means 8 comprise a feeding bin 9 arranged upstream of the granulating machine 2 and having a first entry 10 of the loose material to be granulated, a second entry 11 of the fine powders coming from the pneumatic transport means 7 and at least an exit 12 of the loose material to be granulated.

The feeding means 8 also comprise a dosing belt 13 arranged downstream of the feeding bin 9 and upstream of the inlet mouth 2a of the granulating machine 2. In particular, the dosing belt 13 can consist of a weighing belt or a similar apparatus.

As shown in Figure 1, the regulation means 4 can consist of pumping means able to pump the fluid, specifically water, towards the dispensing means of the granulating machine 2.

Usefully, the plant 1 comprises a dust exhaust filter 14 connected to a suction fan 15 and connected to the suction means 5 and arranged upstream of the granulating machine 2.

In particular, the dust exhaust filter 14 has an inlet 16 connected to said pneumatic transport means 7 and an outlet 17 connected to the second entry 11 of the feeding bin 9.

The plant 1 also comprises a conveyor belt 18 arranged at the outlet mouth 2b of the granulating machine 2.

Usefully, the detection means 3 of the humidity of the granulated material can consist of at least a humidity sensor arranged, e.g., along the conveyor belt 18 and able to detect (or deduce by calculation) the percentage of humidity content of the granulated material coming from the outlet mouth 2b.

A different positioning of the humidity sensor 3 cannot however be ruled out. As illustrated in the embodiment of Figure 1, the plant 1 can have an elevator 19 arranged downstream of the conveyor belt 18 and able to bring the granulated material at a higher level.

The plant 1 comprises a separation apparatus, generally indicated by the reference number 20 arranged downstream of the elevator 19 and having the air sorter 6 and extraction means 21 of the granulated material.

In particular, the extraction means 21 can consist of an extractor belt able to move the granulated material to the subsequent processing stages.

Advantageously, the separation apparatus 20 may comprise separation means 22 able to separate any lumps from the rest of the granulated material.

Usefully, the plant 1 may comprise movement means, not shown in the figure, able to move the separated lumps to bring them up to the feeding bin 9, or elsewhere, for the reuse of the lumps themselves.

If necessary, the separated lumps can be used as they are for later processing stages.

In practice, the use of the air sorter 6, together with the use of separation means 22, allows to limit excessive variations in particle size of the granulated material, minimizing the presence of extremely granulated and wet particles and of fine and dried powders.

The operation of plant 1 is described below.

The loose material to be granulated is introduced into the feeding bin 9 through the first entry 10.

The loose material to be granulated is then dosed and moved towards the granulating machine through the opening/closing of the exit 12 and through the dosing belt 13.

Once introduced into the granulating machine 2 through the inlet mouth 2a, the loose material is humidified and granulated to obtain a material of desired particle size and with a predefined percentage of humidity, preferably between 5% and 10%.

Subsequently, the granulated material is moved by the conveyor belt 18 and by the elevator 19 to the separation apparatus 20.

During this movement, the humidity sensor 3 detects the humidity of the granulated material and the pumping means 4 regulate accordingly the amount of water introduced into the granulating machine 2.

The separation apparatus 20 separates from the granulated material the fine powders by means of the air sorter and any lumps by means of the separation means 22. The fine powders are then moved by means of the pneumatic transport means 7 towards the dust exhaust filter 14 and, therefore, are reintroduced into the feeding bin 9, or elsewhere, together with the loose material to be granulated. Furthermore, the lumps of granulated material eventually separated by the separation means 22 can be reintroduced into the feeding bin 9.

In practice it has been ascertained how the described invention achieves the proposed objects.

In particular, the fact is underlined that the use of suction means, i.e. of means which are able to separate and move the fine powders through the use of air, allows to reduce the percentage of humidity content of the powders themselves during the transport to the granulating machine.

Therefore, the use of the granulating machine, together with the use of the suction means, allows to maintain low humidity levels of the granulated material, greatly reducing the percentage of water added during the humidification stage and virtually eliminating the need to employ a drying system of the granulate itself.

Moreover, the use of the air sorter, together with the use of separation means, allows to limit excessive variations in particle size of granulated material, minimizing the presence of extremely wet and granulated particles and of fine and dried powders.

In this regard, for illustration purposes, a table is shown in figure 2 wherein is shown a possible particle size obtainable at the press after the plant for granulation according to the invention (meaning the material already subjected to sieving with rotary screen at the press with a 2mm by 2mm mesh).

This also entails a considerable improvement in the flowability of the granulated powders thus obtained (meant as the reduction in the flowability angle), quantifiable in a decrease by between 8° and 10° of the sliding angle with respect to what detected for dry ground powders that are humidified with processes of the known type.

Furthermore, the granulated powders thus obtained feature a considerable improvement in the pressing speed, quantifiable as the reduction in the pressing time, i.e. an increase by 8-10% of the strokes per minute at the press.

Claims

1) Plant (1) for the granulation of loose material, comprising at least a granulating machine (2) having at least an inner chamber with at least an inlet mouth (2a) of a loose material to be granulated and at least an outlet mouth (2b) of a granulated material, said granulating machine being able to dispense a fluid within said chamber and to mix the loose material and the fluid to obtain the granulated material, characterized in that said granulating machine (2) comprises detection means (3) able to detect the humidity value of the loose material and regulation means (4) able to regulate the amount of fluid introduced into said chamber depending on the detected humidity of the loose material, and in that said plant (1) comprises suction means (5) arranged downstream of said granulating machine (2) and able to separate any fine powders from the granulated material coming from said outlet mouth (2b) and to move the fine powders towards said inlet mouth (2a) of the granulating machine (2), for the reuse of the powders themselves, wherein said regulation means (4) and said suction means (5) reduce the percentage of added fluid, by eliminating the need to employ a drying system.

2) Plant (1) according to claim 1, characterized in that said suction means (5) comprise at least an air sorter (6) arranged downstream of said granulating machine (2) and able to separate said fine powders from said granulated material coming from the outlet mouth (2b).

3) Plant (1) according to claim 2, characterized in that said suction means (5) comprise pneumatic transport means (7) connected to said at least one air sorter (6) and able to transport said fine powders upstream of said granulating machine (2).

4) Plant (1) according to one or more of the preceding claims, characterized in that it comprises feeding means (8) of said loose material to be granulated associated with said inlet mouth (2a) of the granulating machine (2).

5) Plant (1) according to claim 4, characterized in that said feeding means (8) comprise at least a feeding bin (9) arranged upstream of said granulating machine (2) and having a first entry (10) of the loose material to be granulated, at least a second entry (11) of the fine powders coming from said suction means (5) and at least an exit (12) of the loose material to be granulated.

6) Plant (1) according to claim 5, characterized in that said feeding means (8) comprise at least a dosing belt (13) arranged downstream of said feeding bin (9) and upstream of said granulating machine (2).

7) Plant (1) according to one or more of the preceding claims, characterized in that it comprises at least a dust exhaust filter (14) connected to said suction means (5) and arranged upstream of said granulating machine (2).

8) Plant (1) according to one or more of the preceding claims, characterized in that said dust exhaust filter (14) has an inlet (16) connected to said pneumatic transport means (7) and an outlet (17) connected to said second entry of the feeding bin (9).

9) Plant (1) according to one or more of the preceding claims, characterized in that said detection means (3) comprise at least a humidity sensor (3) or the like.

10) Plant (1) according to one or more of the preceding claims, characterized in that it comprises separation means (22) arranged downstream of said granulating machine (2) and able to separate any lumps from the granulated material coming from said outlet mouth (2b) and to move said lumps towards said inlet mouth (2a) of the granulating machine (2), for the reuse of the lumps themselves.

11) Plant (1) according to one or more of the preceding claims, characterized in that it comprises at least a separation apparatus arranged downstream of said granulating machine (2) and having extraction means of said granulated material and at least one of said air sorter (6) and said separation means (22). 12) Plant (1) according to one or more of the preceding claims, characterized in that said regulation means (4) are able to regulate the amount of fluid introduced into said chamber to maintain a predefined percentage of humidity of said granulated material between 5% and 10%.