Nowadays the mixing of agglomerate composite stone may be realized both in a continuous way by means of a screw extruder and in a discontinuous way by means of blendors with a horizontal or vertical axis.

The extrusion technology is primarily used by the polymer and plastics industries.

The extruders are used and are fit only for very fluid mixtures with a high binder content. The extruders are made of cylinders with rotating shafts on which propellers are placed, these propellers have to carry and to mix the mixture. The extruders may have one or two screws (the two screw extruders may be corotating or counterotating) .

The extrusion technology forecasts the continuous and separate dosage of every single component in the same point of the same cylinder, obtaining a single mixing in a continuous way. They are used to produce, in a continuous way, small mixtures in bulk, but constant both for mixing homogeneity and for color shade.

Advantages :

1. Simplification and plant reduction.

2. Continuous production. 3. Vacuum mixture production as well.

4. Complete unloading of the mixture mixed by the cylinder .

5. Constancy in homogeneity, mixing and color shade .

6. Rapid and fast cleaning, as the surface in contact with the mixture is small.

7. Low use of cleaning products (solvents in case of binder resin) .

Disadvantages :

1. Only very fluid mixtures may be obtained (with a high binder content and low specific weight) . 2. Component premixing is not possible.

3. Great quantities of mixture cannot be realized.

4. Mixture contamination due to the cylinder and/or the shaft and tooling wear.

The technology of mixing in a discontinuous way is primarily used by conglomerate and composite agglomerate industries.

The discontinuous blendors with one or two shafts (the two shaft blendors may be corotating or counterotating) may be either of the horizontal or of the vertical type.

The blendors are often cylindrical containers, containing blades different in number, shape or size that have the function to mix in a discontinuous way, but simultaneously, the unloaded material. The technology of mixing in a discontinuous way is characterized by the discontinuous dosage of a determined quantity of the different components in order to obtain a single mixture (batch) . The blendors may be used to obtain mixtures that are a little fluid (with a very low binder content) and very compact.

Unlike the continuous mixing, in order to obtain a determined quantity of final mixture, it is necessary to repeat "n" times the single batch and there is no guarantee for a mixture and color shade homogeneity among the single different mixtures .

Advantages:

1. A little fluid but very compact and homogeneous mixture (with a very low binder content) may be obtained. 2. Component premixing may be realized.

3. Great quantities of mixture for each single batch may be realized.

Disadvantages :

1. Continuous production is not possible. 2. Vacuum production is not possible.

3. A complete unloading of the mixture cannot be realized (which may cause contamination) .

4. It is difficult to obtain a constancy in homogeneity, mixing and color shade between a cycle and another. 5. Difficulty in cleaning as, often, the blendors are not very practical and accessible.

6. Huge use of cleaning products (solvents in case of binder resin) due to the blendors size and inaccessibility.

7. Contamination of the final product due to cleaning difficulties.

It would be desirable to have a machine that presents the advantages of both systems, i.e. the system what uses extruders and the system that uses blendors.

This purpose has been reached by means of the machine this patent application for industrial invention wants to protect. This machine realizes a perfect and homogeneous continuous mixing of agglomerate composite stone which contain: granulate and binder in a low quantity of any nature, any shape, any size, any specific weight. The continuous mixing occurs through a suitable dosage of the raw material in a fixed cylinder provided inside with a rotating shaft activated by an appropriate engine. On that shaft, propellers, blades and pins are provided in a fit sequence.

The raw materials are unloaded either simultaneously in the same point of the cylinder or in several different points. The solution idea will be better clarified by making reference to the accompanying tables where it is described with an indicative and not binding purpose .

Table 1/4 is an axonometric view of the cylinder.

Table 2/4 shows the section plane of the cylinder in order to show its inner side.

Table 3/4 shows the machine diagram with the cylinder feeders and the frame in which the cylinder unloads the mixture.

Table 4/4 is an exploded view of the cylinder and of its inner side.

Referring to the figures, the machine is essentially made up of a hollow cylinder (1); that cylinder has on its inner side a shaft (2) moved by an engine (3) ; that shaft has on its outer surface, at regular spaces, pins (4), propellers (5) and blades (6) .

The inner surface of the hollow cylinder (1) has pins (7) as well, these pins extend over the external surface of said cylinder. The cylinder (1) has holes (8) for loading the materials from hoppers, tanks or silos (9) through conveyor tubes (10) .

The mixture is unloaded from the end of the cylinder (1) into the hopper (11) . With the described and illustrated machine a new system for the continuous mixing of agglomerate composite stone is realized. This may happen thanks to the right equipment of the shaft (2) and of the cylinder (1) with the suited pins (4), propellers (5) and blades (6) that will be placed in specific areas depending on the type of mixture you want to obtain.

The machine also allows the load of component raw materials in different areas or in the same area, depending on the mixture and/or the mixing you want to obtain.

Thanks to these machine characteristics, it is possible to obtain in a continuous way a constant mixture, which is perfectly mixed and homogeneous both in the structure and in the coloring.

In conclusion, the machine allows an initial premixing step and carrying of the mixture, and the following mixing and homogenizing of the melted granulometric material, in order to have a mixture ready to be used either as a direct casting, such as the injection in vacuum molds, or as an indirect casting pouring the mixture in simple or complex molds that, through the combined action of vacuum and vibrations, create elements from simple and/or complex surfaces that change in dimension, thickness, shape, structure and coloring.

In the cylinder, thanks to the shaft equipments and to their set-up, a deep mixing of the components may be obtained, and both the color and the binder may be disgregated and finely distributed in the mixture.

This new system for the continuous mixing of agglomerate composite stone may bring the following advantages: 1. Continuous productivity.

2. Homogeneous mixture.

3. Optimum process control.

4. Increase in total productive capacity. 5. Extreme facility in cleaning operations.

6. Big reduction in cleaning time.

7. Reduction in cleaning products (solvents in case of binder resin) .

8. Simplification and plant reduction. 9. Reduction in energy and maintenance costs.

10. Production may be interrupted at any moment, with no scrap production.

11. Changes may be brought to the production line.

12. Facility and time reduction in changing the product, different both in structure and coloring.

13. Mixture not contaminated by the cylinder and/or the shaft unloading.

The parts in contact with the mixture will be made of metal; or steels; or alloys; or composite materials; or ceramic materials; to allow or not the mixture to be contaminated by grey / black coloring because of the wear due to the abrasion of mixture which comes in contact with metal and/or alloy parts. The productive capacity will depend both on the shaft size and on its rotation speed, the shaft is operated by an engine set or not by an inverter. The machine description and the related figures are shown, as already said, with an indicative and not binding purpose, but changes may be made both in the number and in the shape and specific location of pins, propellers and blades on the shaft (2) inside the cylinder (1), without departing from the patent domain that is defined by the following claims.