A process and a plant for manufacturing ventilated bricks, having a calibrated longitudinal size

Abstract

 The process comprises following stages: extrusion of the bricks (10) along a longitudinal axis (x) thereof, from a humid mixture; drying the extruded bricks (10); calibrating the dried bricks (10) using a cutter tool, milling along two opposite end surfaces which are perpendicular to the longitudinal axis (x); firing the bricks after they have been milled. The invention also relates to a plant for actuating the process.

Description

[0001] The ventilated, i.e. perforated, brick, is an economical item in the context of overall costs in the construction industry.

[0002] These bricks are mass produced using a process which includes extrusion of the single bricks from a damp sand/clay mixture, drying the extruded lengths and a final firing which gives the final products the necessary hardness and resistance to compression.

[0003] The described process does not enable controlling and performing a sufficiently precise uniformity in the lengths of the bricks, with reference to their longitudinal size, i.e. the dimension parallel to the extrusion direction thereof.

[0004] The bricks are laid in successive layers, with their longitudinal axis vertically-oriented. Each layer is a series of bricks laid side-by-side on a layer of mortar or cement. The building of a wall involves laying a plurality of such strata of bricks, each row separated from the next by a layer of mortar or cement. As the bricks do not have a uniform longitudinal side, in order for each row to exhibit a horizontal surface, which is necessary for correct construction of a wall, the difference in sizes has to be compensated for by quite thick layers of mortar, sinking the bricks into the layers by an amount corresponding to the inequality in the brick sizes. This leads to greater consumption of mortar or cement, and consequently to higher costs.

[0005] Secondly, the care required for laying the bricks means longer working/laying times, and once more consequentially higher costs. It is further necessary to consider that the specialists having the skills needed for correct bricklaying are quite expensive.

[0006] To limit the above-described drawbacks, a process has been developed which comprises milling the bricks on their laying surfaces after the firing stage. This has not, however, reduced costs, as the milling of fired bricks is a very expensive operation, comparable to traditional brick-making. After firing the bricks are extremely hard and need special milling machines, very expensive and having very short working lives.

[0007] The main aim of the present invention is to provide a process for making bricks which bricks have a calibrated longitudinal size, thus obviating the above-described drawbacks in the prior art.

[0008] Further characteristics and advantages of the present invention will better emerge from the detailed description that follows, illustrated purely by way of non-limiting example in the accompanying figures of the drawings, in which:

Figure 1 is a schematic perspective view of a plant for carrying out the process of the present invention;

Figure 2 is a view from above of the plan of figure 1.

[0009] With reference to the figures of the drawings, the process of the present invention comprises the following stages:

extrusion of the bricks 10 along a longitudinal axis x from a humid mixture;

drying the extruded bricks 10;

calibrating the dried bricks using a cutter, at two end surfaces which are perpendicular to the longitudinal axis x, the cutter including at least two rotating tools 2 having flexible abrasive blades;

firing the milled bricks 10.

[0010] In the first stage, the bricks 10 are extruded, starting from a damp known-type mixture, in the direction of the longitudinal axis x thereof, i.e. the axis which defines the load compression direction which the bricks 10 are subjected to when laid. In the illustrated embodiment, the bricks 10 are constituted by perforated bricks, having a plurality of channels all parallel to the longitudinal axis x. This type of brick is laid in such a way that the longitudinal axis x, and thus the channels crossing the bricks, are vertically oriented.

[0011] Following extrusion, the process next comprises the bricks 10 being dried in order to reduce the humidity present in the mixture they are made of.

[0012] The subsequent calibrating stage, after drying, is the stage in which the longitudinal size of the bricks 10 can be calibrated with considerable precision. They are extruded in longer longitudinal sizes than necessary, and are then milled on the laying surfaces, i.e. those perpendicular to the longitudinal axis x. In this way the bricks 10 are given the correct longitudinal size, by mechanically removing a predetermined amount of material from the laying surfaces.

[0013] The flexible abrasive blades 3 of the rotating tools 2 are arranged in a circular crown, coaxial to the rotation axis of the rotating tools 2 and at one end are constrained to the rotating tool 2, while at another end they are free. The abrasive blades 3 are made of or covered with an abrasive material, and are provided with a degree of flexibility. This means that the dried mixture the bricks 10 are made of can be removed without crumbling uncontrolledly and without clogging up the rotating tools 2.

[0014] The rotating tools 2 preferably exhibit a rotation axis which is parallel to the longitudinal axis x of the bricks 10 and the flexible abrasive blades 3 of each rotating tool 2 define an operative abrasion plane which is perpendicular to the axis of rotation of the rotating tool 2. The rotation axes of the rotating tools 2 are preferably aligned.

[0015] In the preferred embodiment of the process the dried bricks 10 are moving on a conveyor plane along a direction which is perpendicular to the respective longitudinal axes x of the bricks. The rotating tools 2, which are frontal millers, in effect, are arranged on opposite sides of the conveyor plane. The bricks 10 pass between the rotating tools 2, with the laying surfaces of the bricks 10 facing the flexible abrasive blades 3. The rotating tools 2 can be located in a fixed position or can be permitted to slide along a parallel direction to the axes of rotation thereof, in order to enable a correct positioning of the tools at the passage of each brick 10.

[0016] The preferred type of plant for actuating the described process comprises: an extrusion station for bricks 10 along a longitudinal axis x thereof, from a humid mixture; a drying station of the extruded bricks 10, a firing station of the bricks 10; a conveyor plane 11, which takes the bricks 10 from the drying station towards the firing station in a transport direction which is perpendicular to the longitudinal axis x of the bricks 10. The plane further comprises at least two rotating tools 2 which exhibit the flexible abrasive blades 3, which at an end thereof are constrained to a rotating tool 2 and which at another end thereof are free. The flexible abrasive blades 3 of each rotating tool 2 define an operational abrasive plane which is perpendicular to the rotation axis of the rotating tool 2, the rotating axes of the rotating tools 2 being aligned to one another. The two rotating tools 2 are arranged on opposite sides of the conveyor plane. The plant can however be provided with several pairs of rotating tools 2, located in succession along the conveyor plane 11.

[0017] The proposed process has important advantages. It enables bricks to be made having a longitudinal dimension which is calibrated with considerable precision, and with contained costs, limited to the use of rotating tools having flexible abrasive blades which are quite cheap. The bricks obtained using the process of the invention further enable a considerable reduction of costs for laying and realising construction work.

[0018] They require a lower expenditure on mortar and cement, as it is not necessary to compensate for size differences in the bricks, and they also render the laying operation easier and quicker.

Claims

1. A process for manufacturing ventilated bricks, having a calibrated longitudinal size, characterised in that it comprises following stages:

extrusion of the bricks (10) along a longitudinal axis (x) thereof, from a humid mixture;

drying the extruded bricks (10);

calibrating the dried bricks (10) using a cutter tool, milling the bricks (10) along two opposite end surfaces thereof which are perpendicular to the longitudinal axis (x);

firing the bricks (10) after they have been milled.

2. The process of claim 1, characterised in that the calibrating operation using the cutter tool is done using at least two rotating tools (2) provided with flexible abrasive blades (3).

3. The process of claim 2, characterised in that the flexible abrasive blades (3) of the rotating tools (2) are arranged in a circular crown, coaxial to the rotation axis of the rotating tools (2) and at an end thereof are constrained to a rotating tool (2) and at another end thereof are free.

4. The process of claim 2, characterised in that the rotating tools (2) exhibit a rotation axis which is parallel to the longitudinal axis (x) of the bricks (10).

5. The process of claim 4, characterised in that the flexible abrasive blades (3) of each rotating tool (2) define an operating abrasive plane which is perpendicular to the rotation axis of the rotating tool.

6. The process of claim 5, characterised in that the rotation axes of the rotating tools (2) are aligned.

7. The process of claim 6, characterised in that the dried bricks (10) are in motion on a conveyor plane along a direction which is perpendicular to the longitudinal axes (x), the at least two rotating tools (2) being arranged on opposite sides of the conveyor plane.

8. Use of a rotating tool (2), having flexible abrasive blades (3) which are arranged in a circular crown which is coaxial to the rotation axis of the rotating tool (2) and which blades (3) are attached at an end to the rotating tool (2) and at another end are free, for calibrating dried bricks (10).

9. A plant for making bricks having a calibrated longitudinal dimension, comprising: a station (10) for extruding bricks along a longitudinal axis (x) thereof, from a humid mixture; a firing station of the bricks (10); a conveyor plane (11), which takes the bricks (10) from the drying station towards the firing station in a transport direction which is perpendicular to the longitudinal axis (x) of the bricks (10), characterised in that it comprises at least two rotating tools (2), predisposed to calibrate dried bricks (10) at two opposite end surfaces thereof which are perpendicular to the longitudinal axis (x) which are provided with flexible abrasive blades (3), arranged in a circular crown, coaxial to the rotation axis of the rotating tools (2) and at an end thereof are constrained to a rotating tool (2) and at another end thereof are free; the rotating tools (2) exhibiting a rotation axis which is parallel to the longitudinal axis (x) of the bricks (10); the flexible abrasive blades (3) of each rotating tool (2) defining an operating abrasive plane which is perpendicular to the rotation axis of the rotating tool; the rotation axes of the rotating tools (2) being aligned; the at least two rotating tools (2) being arranged on opposite sides of the conveyor plane.

Drawing