METHOD FOR THERMAL INSULATION OF HOLLOW BRICKS AND APPARATUS FOR THERMAL INSULATION OF HOLLOW BRICKS Technical field

The present invention relates to a method for thermal insulation of hollow bricks and to the apparatus for thermal insulation of hollow bricks. Background art

As is known, currently applicable statutory provisions tend to increase considerably the thermal resistance of peripheral masonry, and therefore, in order to comply with the several statutory provisions, it is necessary to either increase the thickness, with a great increase in weight, laying costs and loss of walkable surface, or add insulating material inside or outside such masonry, so as to obtain the desired insulation values.

In order to try to solve the problem, bricks are already known which are constituted by a single preassembled item, obtained from two blocks of bricks with an interposed insulating panel of cork or polystyrene.

This embodiment, which is certainly valid from a thermal standpoint, is expensive due to the complexity of the production process. Disclosure of the invention

The aim of the invention is to solve the problems described above, by providing a method for thermal insulation of hollow bricks that allows to obtain complete filling of the hollow of the bricks by means of expanded polystyrene, so as to comply with statutory provisions regarding thermal insulation.

Within this aim, an object of the invention is to provide a method that can be performed continuously and automatically, leading to the obtainment of an article that, is particularly valid from a functional standpoint and which is easy to provide.

Another object of the present invention is to provide an apparatus for automatic management of the method, which thanks to its particular constructive characteristics is capable of giving the greatest assurances of

reliability and safety in use.

Another object of the present invention is to provide a method and an apparatus that can be obtained easily starting from commonly commercially available elements and materials and are also competitive from a merely economical standpoint.

This aim, as well as these and other objects that will become better apparent hereinafter, are achieved by a method for thermal insulation of hollow bricks, characterized in that it consists in: positioning the bricks so that hollow channels of the bricks are arranged substantially horizontally, injecting an expandable plastic material into said hollow channels, vaporizing said expandable plastic material, removing the expanded plastic material from the faces of said bricks, and freeing from said expanded plastic material the ends of said hollow channels.

The above aim and objects are also achieved by an apparatus for thermal insulation of hollow bricks, characterized in that it comprises, in succession, an injection press for expandable plastic material, which comprises a first plate and a second plate, which can engage the ends of the hollow channels of the bricks being treated, downstream of said press there being a station for cleaning by means of rotating brushes and a station for thermal treatment for freeing the ends of the hollow channels from the expanded plastic material. Brief description of the drawings

Further characteristics and advantages of the present invention will become better apparent from the description of a preferred but not exclusive embodiment of an apparatus and a method for thermal insulation of hollow bricks, illustrated by way of non-limiting example in the accompanying drawings, wherein:

Figure 1 is a schematic plan view of the apparatus for thermal insulation of hollow bricks; Figure 2 is a perspective view of a resulting brick;

Figure 3 is a perspective view of the press for injecting the expandable plastic material into the hollow channels;

Figure 4 is a front elevation view of the press;

Figure 5 is a view, taken along the brick transfer direction, of the press in the open position;

Figure 6 is a sectional view of the detail of the plates of the press, which can be coupled hermetically to the brick into which the injection is to be performed;

Figure 7 is a schematic perspective view of the plates of the press with the corresponding injectors;

Figure 8 is a front elevation view of the station for brushing the bricks into which injection has been performed;

Figure 9 is a view of the brushing station in the brick advancement direction; Figure 10 is a view of the detail of the thermal treatment station for freeing the ends of the hollow channels from the expanded plastic material. Ways of carrying out the invention

With reference to the figures, the apparatus for thermal insulation of hollow bricks, generally designated by the reference numeral 1 , comprises a press 2 into which hollow bricks 3 are introduced, such bricks having the peculiarity that they are arranged so that hollow channels 3a of the bricks have a substantially horizontal arrangement.

According to a preferred embodiment, the bricks 3, which have any shape, have a percentage of hollow space, understood as the ratio of void to solid, which ranges for example from 45 to 55%.

The bricks 3 have the ends designed to mutually match up with male protrusions 3b that enter corresponding female couplings 3c, and four bricks are advantageously arranged side by side and placed on a horizontal conveyor 6, which moves stepwise, so as to move the groups of bricks at the press 2.

The press 2, as shown in Figures 5, 6 and 7, has a first plate 10 and a second plate 1 1 , which are opposite one another and are supported by corresponding bedplates 12 and 13, which can slide on columns 14 by way of the actuation of fluid-actuated cylinders, both designated by the reference numeral 15, which are designed to move the bedplates and consequently the plates 10 and 11 at considerable speed and with great precision, thanks to the fact that they are fluid-actuated cylinders.

A first microperforated plate 20 and a second microperforated plate 21 are arranged respectively at the plates 10 and 11 and are placed at the opposite faces of the brick 3, at the ends of the hollow channels 3 a.

According to a preferred embodiment, the first microperforated plate 20 defines a recess 22, which corresponds to the positioning region of a strip 23 of expanded plastic material, which is commonly known as slug.

At the peripheral region of the second microperforated plate 21 there are sealing gaskets 25, which are provided with a coupling shank 26 that enters a retention seat 27, which is flanked by wider portions 28 that allow the expansion and accommodation of a wider hollow portion 29 of the sealing gasket, which for example can be made of foamed silicone.

This type of gasket allows to provide an initial injection step in which a hermetic coupling is provided, leaving, at the face of the brick, an interspace that has a thickness of preferably 5 to 15 millimeters which allows the injection of an expandable plastic material, which is preferably constituted by polystyrene filled with graphite but can also be constituted by other expandable plastic materials. At the plate 1 1 there are injectors, designated by the reference numeral 31, which are advantageously two in number for each brick arranged for treatment and have such characteristics as to allow an angle of diffusion of the polystyrene that is suitable for its uniform distribution within the interspace. Control of the step for injection of the expandable plastic material

occurs by means of a volumetric dosage, a time and a pressure that can range from 0.5 to 1.8 bars.

The pressure value must be adjusted precisely, so as to avoid turbulences that might hinder correct filling. The injectors 31 perform injection with the preset pressure value, and on the opposite side it is possible to provide, on the first plate 10, a preset value of partial vacuum, so as to allow complete and uniform filling of the several hollow channels.

Once the step for injection of the material has been performed, complete closure of the plate 11 on the brick is performed and can be obtained by compressing the gasket 25, which can flatten and be accommodated within the wider portions 28, thus allowing to position the plate 1 1 so that it adheres to the end of the brick.

Once total closure of the plates against the brick has been performed, a first vaporization is performed with the introduction of a first steam from the opposite side with respect to the slug 23, through the microperforated plates of the press, obtaining an expansion and sintering of the loose polystyrene that is present in the hollow channels and in particular of the polystyrene of the slug. A second vaporization step is then performed, introducing the so- called second steam, and complete sintering of the remaining portion of the polystyrene is performed.

In this step, the pressure, the injection sequence of the two sides, and the time and evacuation of condensation are controlled. Once the expansion step has been performed, the press is opened to release the articles and the conveyor 6 is made to advance to carry the articles with plastic material injected therein at a station 40 for removing the plastic material from the faces of the bricks.

This station comprises a single rotating brush 41, at the face that is not affected by the slug, and two separate brushes 42, at the face that is

affected by the slug.

There is also an upper chain conveyor, designated by the reference numeral 45, which engages the bricks in order to retain them in position on the conveyor 6 during the brushing step which is designed to remove the excess polystyrene on the surface of the block.

Once the step for cleaning the faces of the bricks has been performed, the bricks are introduced in a station where in practice the end of the individual hollow channels is freed to better allow the seating of mortar.

This station for freeing the ends of the channels, designated by the reference numeral 50, is shown in Figure 10 and provides heat sources which are advantageously constituted by burners 51 which produce the heat- shrinking of the polystyrene in the cavities of the block, so as to allow correct assembly of the blocks.

Advantageously, the temperature measured on the product can range from 400 to 700 ⁰ C and the exposure time of the product per square centimeter ranges from 0.02 to 0.06 seconds.

In this step, the ends of the channels are cleared for a few millimeters, thus obtaining the possibility of a better connection to the mortar for providing the masonry. The thermal treatment, although the use of flame burners has been found to be optimum, might optionally be obtained also with other heat generating elements.

The method for insulating hollow bricks substantially consists in injecting an expandable plastic material, such as graphite-filled polystyrene, into the hollow channels of the brick, which are arranged horizontally.

The injection step is obtained by applying hermetically the plates of the press at the ends of the channels, using a peripheral gasket which, besides compensating for the dimensional differences of the several bricks, also allows to create a suitable interspace for filling all the holes of the brick with just two injectors.

In order to ensure constant filling of all the holes, it has been found to be optimum to provide an aspirator that is arranged on the opposite side with respect to the injectors and is operated simultaneously with the injection, generating a weak partial vacuum that facilitates filling. An important aspect further consists in that the plate is stopped in position in precise positions, so as to ensure tightness both in the initial step, in which it is necessary to create the interspace, and in the final step, in which the plate of the press is arranged in contact thanks to the fact that the type of gasket that is used can retract completely into its seat without suffering damage or wear.

The step for expansion and sintering of the polystyrene has been found to be optimum, by performing the introduction of the first steam on the opposite side with respect to the slug, so that during the expansion step no excessively violent expansions are generated, which would "pressurize" the brick due to the residual tension that the polystyrene applies to the walls, such pressure making the material fragile and subject to easy breakage.

Expansion must be performed correctly, since, should the polystyrene expand scarcely, it would not sinter enough and would remain in the loose state without fixing itself to the article. Another aspect of the invention consists in that after the brushing step that cleans the faces of the brick from the expandable material, the brick is made to transit at a preset speed in front of flame diffusers, which advantageously have a diameter of 22 millimeters with nozzles that are arranged so that three in number are on one side and two in number are on the side that has the slug that must not be damaged. The nozzles are arranged at a distance of 50 to 150 millimeters from the surface to be treated, and the generated heat causes the instantaneous shrinkage of the expanded plastic material to the desired depth.

The operating pressure of the gas is preferably 1 bar and the speed of mutual translational motion between the flames and the material is critical

for correctly performing the shrinkage of the polystyrene and ranges advantageously from 1 to 5 seconds per linear meter.

From what has been described above it. is therefore evident that the invention achieves the proposed aim and objects, and in particular the fact is stressed that a method is provided which allows to obtain continuously and quickly the filling of the hollow channels with expanded plastic material, so as to optimize thermal insulation values; moreover, the presence of the slug, i.e., of the strip of expanded plastic material arranged on one face of the brick, allows to interrupt the thermal bridge that would be created by the mortar used to provide the masonry.

The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims.

All the details may further be replaced with other technically equivalent elements.

In practice, the materials used, as well as the contingent shapes and dimensions, may be any according to requirements.

The disclosures in Italian Patent Application No. MI2008A000302 from which this application claims priority are incorporated herein by reference.

Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.