RU2268141C2 - Method and a device of concrete casting for manufacture of concrete products - Google Patents

Abstract

FIELD: construction industry; methods and devices for casting of concrete products.

SUBSTANCE: the invention is pertaining to construction industry, in particular, to the methods of manufacture of concrete products and to the installation for its realization. More particularly, the invention is pertaining to a casting method of production of concrete products. The technical result of the invention is an increased productivity, improved quality of the concrete products surface due to the more effective removal of the mold. The method of manufacture of the concrete products provides, that the concrete is cast in, at least, one shuttering mold made out of a material, which may be compacted by compression and then may be broken to pieces. The indicated shuttering mold contains the upper shuttering half-mold and the lower shuttering half-mold. At that the lower shuttering half-mold contains a replica of a part of the product, and the upper shuttering half-mold contains an additional part of the replica of the product and a gate channel consisting of one or more gate runners for a gravitational casting and one or more the air exhaust channels or in another version the lower shuttering half-mold contains a replica of a part of the product and a gate channel consisting of one or more gate runners for a siphon casting the upper shuttering half-mold contains an additional part of the replica of the product and one or more the air exhaust channels. The invention is also pertaining to a concrete product by the methods indicated in the invention. The invention is developed in the dependent points.

EFFECT: the invention ensures an increased productivity, improved quality of the concrete products surface due to the more effective removal of the mold.

21 cl, 8 dwg

Description

The present invention relates to a casting method, intended, in particular, for the manufacture of concrete products, and to an installation for implementing the method.

In the following description, the term "concrete" ("concrete") is used to define both the initial mixture and the finished product, and covers the so-called cement, as well as any mixture of cement with suitable additives, binders or other materials that may be required in accordance with applications.

According to the prior art, concrete products are usually manufactured by a method that involves the use of formwork made of wood, plastic or, preferably, a metal that reproduces the shape of the manufactured product. According to this known method, concrete is poured while it remains liquid into the formwork in which it remains until it sets, forming a finished product. The formwork is then opened to release the product, and then cleaned to remove any residual concrete. It should also be noted that the inner surface of the formwork usually has to be treated with suitable chemical additives that eliminate the adhesion of concrete to the metal surface and thereby facilitate the cleaning step, but do not exclude it. However, these chemical additives are usually dangerous or even toxic.

From the foregoing it is clear that the known method has many disadvantages that significantly limit its performance, namely:

- the use of formwork, which has to be assembled and disassembled before and after each pouring, and which requires frequent cleaning and chemical treatments, leads to significant maintenance costs and reduced productivity of the corresponding installation;

- casting concrete into formwork does not allow for a continuous process, since it is necessary to fill out each formwork separately;

- it is impossible to manufacture hollow non-linear products, such as bent pipes, T-shaped joints, etc.

Therefore, the problem underlying the present invention is to develop a method that eliminates the aforementioned disadvantages.

This problem is solved using the concrete casting method described in the attached claims, and the corresponding installation.

Additional characteristics and advantages of the concrete casting method according to the present invention will become clearer after studying the description of specific embodiments of the invention, given below as a non-limiting example with reference to the following drawings:

figure 1 presents a schematic side view of a specific structural element of the installation for concrete casting in accordance with the present invention;

on figa, 2B, 2C and 2D shows four different types of casting concrete into formwork in accordance with the present invention;

figure 3 presents a side view depicting in cross section a manual installation for the manufacture of formwork;

on figa presents in perspective a "raw" block of pavers, which can be manufactured by the method according to the invention;

on figv presents a side view in cross section of a formwork form for the manufacture of the block depicted in figa;

Fig. 5A is a perspective view of a counterweight of a washing drum that can be manufactured by the method of the invention;

on figv presents in cross section formwork form for the manufacture of the product depicted in figa, side view;

on figa presents tile, which can be manufactured by the method according to the invention, in perspective;

on figv presents in cross section formwork form for the manufacture of tile, depicted in figa;

on figa presents in cross section a T-shaped pipe connector, which can be manufactured by the method according to the present invention;

on figv presents a perspective image of the formwork form for gravity casting, intended for the manufacture of the product depicted in figa, with a partial section;

on figs presents in cross-section formwork mold for siphon molding, intended for the manufacture of the product depicted in figa; and

FIG. 8 is a cross-sectional view of a formwork with an open cross-section for casting from above, corresponding to a particular embodiment of the present invention.

The method of casting concrete in accordance with the present invention is characterized in that the concrete is poured into formwork made of a material that can be compacted and joined by compression, and then crushed. Immediately after compaction, the material can preferably be crushed mechanically. More specifically, the material is selected from the group consisting of molding clay, other suitable clay mixtures, and sand, possibly mixed with suitable binders.

The method in the General case includes the following process steps, in which

a) form one formwork or a set of formwork forms in series from a material that can be compacted by compression, preferably from molding clay or other suitable clay mixtures, or from sand, and these formwork forms reproduce in the reverse form the manufactured product,

b) intermittent or continuous casting of concrete into formwork,

c) ensure the solidification of the product in the formwork form or in each formwork form sequentially,

d) release the product from the formwork form or from each formwork form sequentially, and (optionally)

e) carry out finishing processing of the product.

In step a) the formation of the formwork form (formwork form), you can use the manual process or, preferably, an automatic process.

Figure 3 shows as an example the installation for the manual formation of formwork forms, indicated as a whole by 1. The wooden or metal model 2, reproducing in a positive form the manufactured product, is attached to the plate 3, which is also made of wood, plastic or metal and which, in turn, is attached to the table 4. On the plate 3 is installed flask 5, which is a parallelepiped and is open bottom and top; Model 2 is enclosed in the flask 5, and the flask itself is attached to the plate 7 by means of four connecting rods 6, which pass through the respectively oriented through holes in the table 4 and in the plate 3. In addition, the flask 5 is filled to the top with material, usually with molding clay, which can be sealed by compression, compacting it to such an extent that a formwork 8 is obtained in which the print of the model is stably maintained. The next step is to remove the formwork form 8, which in the particular embodiment shown in figure 3, is carried out by lifting the flask 5 by means of the plate 7, with which it is connected. The installation in question is described as a mobile flask installation. At the same time, it is possible to manufacture a plant in which the flask 5 remains stationary and the slab carrying the model moves, thereby guaranteeing the removal of the formwork 8.

As for the type of material used, which can be compacted by compression, it can be, for example, a so-called molding clay containing suitable amounts of clay material with agglomeration characteristics, so that after adding small amounts of water (about 5%), said clay reaches an adequate degree cohesion.

The tamping step in the material, which can be sealed to form the formwork, is carried out in various ways. According to a first possible method, pressing is carried out by means of mechanical, hydraulic or pneumatic presses. The second method is a ramming method; a flask full of material that has not yet been compacted is repeatedly dropped from a predetermined height to a suitable stop, so that the inertia forces developing at the same time contribute to the compaction of the material. The third method involves the introduction of material that can be compacted into the flask under pressure. The material is introduced by a jet supplied by suitable nozzles under the influence of compressed air or by means of a mechanical rotor.

You can apply various types of casting (step b) of the method) in accordance with the manufactured product. The simplest type of casting is the so-called casting from the top into the formwork with an open cross section, which, as shown in FIG. 2A, involves casting concrete directly into the formwork 8A. On the other hand, the second type, illustrated by way of example in FIG. 2B, provides for the formation of a two-element formwork with an upper half 8B ′ and a lower half 8B. ”In the particular embodiment, the lower half 8B ″ contains an imprint of the product with an open cross section (solid the product corresponding to the example shown in FIG. 2A can be obtained in a similar way), and the upper half 8B ′ comprises a sprue channel 9 for gravity casting and an air outlet or air outlet nye 10 channels.

On the other hand, FIG. 2C shows an example of a formwork mold for siphon casting, that is, bottom-up casting, consisting of an upper formwork half mold 8C ′ and a lower formwork half mold 8C ". In this case, the lower formwork half mold 8C" contains the imprint of the product and the sprue channel 9, and the upper formwork half-mold contains air outlet channels 10.

Similarly, the structure in the example shown in Fig. 20 consists of an upper formwork half-mold 8D 'and a lower formwork half-form 8D ". In this case, casting is also carried out from below, but the jet is pumped from above, so that the gate channel consists of the first section 9', made in the upper formwork half-form 8D ', and the second section 9 "made in the lower formwork half-form 8D". The first section of the sprue channel contains an upwardly extending neck 11 through which a stream of concrete is poured. On the other hand, the second section 9 "is essentially w L-shaped and opens in the area of the base of the print.

In accordance with a particularly preferred embodiment of the invention (shown in FIG. 8), casting nozzle 12 is inserted into the cavity of the formwork mold 8 to form solid products by casting from above into an open cross-sectional area, leaving it at a small distance from the base to minimize turbulence in the fluid the mass of concrete pumped through the nozzle, and therefore minimizing the possible formation of air bubbles that would create defects in the product. Thus, it is possible to achieve the advantages of injection from below, but with greater simplicity of design. In accordance with this type of casting, the nozzle 12 is gradually immersed in the concrete mass, which, due to its fluidity and relatively long setting time, will allow the nozzle to be removed before the product hardens. The fluidity of the concrete mass also allows you to immediately fill the space occupied by the pipe in the said mass, and level the surface. This operation can be facilitated in some cases by slight vibration, which can be subjected to the formwork 8.

In the process according to the invention, the concrete is preferably cast concrete, for example special quick setting concrete for castings or similar products. Particularly preferred concrete is ITALCEMENTI concrete, known under the trademark SCATTO®.

As indicated above, casting can also be carried out continuously, as shown in FIG. As an example, this drawing conventionally shows a casting step in a continuous concrete casting plant in accordance with the present invention. In this case, the formwork 8 comes sequentially from a suitable installation 13, which allows the formation of the formwork from molding clay or a suitable clay mixture, etc. Each formwork half-mold contains on its two opposite front surfaces semi-prints of the manufactured product and the gate. Then, the formwork half-molds are successively articulated by means of installation 13 and transferred to a conventional conveyor belt 14 located below the nozzle 12 for pumping concrete, which pumps the flowing concrete mixture into the formwork. The nozzle 12 is hydraulically connected to the mixing means 15, which prepare a flowing concrete mass from the ingredients in the form of solid particles. Between the mixing means and the nozzle 12 may be located (may be located) means (or means 16) of gravity casting for pumping concrete into nozzles. These injection means 16 are important, in particular, when it is necessary to inject under pressure into the formwork 8.

Step c) of the method according to the invention, in which the product is hardened inside the formwork, is carried out over a period of time, generally varying from 30 to 90 minutes. For the installation shown in figure 1, this step can mainly be carried out during the transportation of clay formwork 8 on the conveyor belt 14. In this case, the curing time will depend on the length of the conveyor belt 14 and its speed. At the same time, it is possible that stage c) hardens in the area located lower along the processing chain from the installation, and optionally in a stationary state.

Step d) the article is freed from the clay formwork by breaking the formwork 8. In fact, the degree of cohesion of the material that can be compressed by compression and of which the formwork is composed is such that it is sufficient to crush the material by vibration with sufficient energy and thereby contribute releasing a concrete product. This operation can be carried out by vibration, pressure or shaking. In the first case, a formwork containing a concrete product and placed on a suitable table connected to a vibrating means, for example a vibrating means operating on compressed air, is subjected to intense vibrations (or injection jets of compressed air) that separate the compacted material from the product. This material is then returned to the formwork molding machine. On the other hand, a method of releasing an article using pressure involves stacking the formwork in the stack and axially compressing the stack of the formwork using a suitable press. And finally, in accordance with the method of release by shaking, the formwork is placed on a suitable platform, which is then dropped to the stop. The impact is transferred to the formwork, causing crushing of the compacted material, after which this material is returned to the molding stage, as in previous cases.

Stage e) finishing processing of the product is carried out by choice, providing at this stage the execution of one or more of the following operations: stripping, trimming and sandblasting.

Scraping is the removal of any traces of compacted material adhering to a concrete product, and is carried out using suitable brushes or jets of compressed air or jets of water under pressure.

Trimming is the removal of areas whose appearance is due to technological requirements (the presence of gate gates, press guides, etc.), and can be carried out manually by means of suitable machines or by means of robots.

At the stage of sandblasting, the surface of the product is treated by the action of jets of compressed air and sand under pressure or by washing with jets of water under pressure.

In order to carry out the casting in accordance with the particular embodiment shown in Fig. 8, the installation shown in Fig. 1 and described above must be equipped with means for vertically moving the nozzle 12 so that it is inserted into the formwork cavity and subsequently removed after casting is completed. The device may also contain vibration means associated with the conveyor belt 14 or with the workstation, which is located in the technological chain immediately after the conveyor belt and on which formwork can arrive for a period of time short enough so that the product does not harden.

On figa, 5A, 6A and 7A shows several examples of products that can be manufactured by the method according to the present invention. This list should in no way be considered as limiting, and it may include any type of product that is usually made of concrete, for example, such as a curbstone of motorways, railway sleepers, building blocks of all types and shapes - solid, with cavities or with open cross sections, pipes of all shapes and sizes, skirting boards, art products of all shapes and types, such as statues, garden benches, vases and even decorative cobblestones, etc.

On figa shows a typical block 17 of the "untreated" pavers, which are usually paved car parking. The use of these blocks made of concrete (inert material), instead of the known paving stones made of plastic, prevents pollution problems associated with the decomposition of plastics in contact with the ground and when exposed to light and atmospheric substances. FIG. 4B is a cross-sectional view of a formwork mold 18 for top casting to form the block shown in FIG. 4A.

5A shows a counterweight 19 of the type that can be used in washing machines. The counterweight 19 contains through holes 20 for mounting it to the base of the appliance. On figv shown in cross section formwork form 21 for the manufacture of the product depicted in figa. The rods 22 are visible, providing through holes 20 in the product.

On figa shows a concrete tile. This product can be manufactured using the formwork shown in FIG. 6B and containing the upper formwork half mold 24 'and the lower formwork half mold 24 ", which are designed to make the product with an open cross section. On the other hand, the upper formwork mold 24' contains the sprue channel For gravity casting 26. The sprue channel 26 ends with a funnel-shaped opening to facilitate the flow of concrete mixture.

On figa shows a T-shaped pipe connector 27. This product cannot be manufactured by known methods of molding, since the core reproducing the cavity inside the pipe cannot be removed immediately after the casting has hardened.

According to the method of the present invention, the T-shaped connector 27 can advantageously be advantageously manufactured by forming a core from a material that can be compressed by compression and then crushed. In step d) of releasing the article, this core will also be crushed to provide the desired T-shaped connector.

On figv shows the formwork for the manufacture of the product depicted in figa. This formwork form comprises an upper formwork half-form 28 'and a lower formwork half-28 "which, when joined together, define a print corresponding in the reverse form to the outer shape of the manufactured product. In the cavity defined by this print, a core 29 is placed in a suitable position, which reproduces in the reverse form, the cavity in the manufactured product. The core 29 contains at each end of the support 30 ', 30 ", 30'", which are installed in the respective saddles formed in two shuttering half ah and whose function it is to keep the core suspended in the appropriate position for the cavity in the article. The core is normally placed in the saddle bottom shuttering mold 28 ", which is then jointed to the upper shuttering mold half 28 '.

Naturally, between the core and the inner walls of the imprint cavity there is a space 31 that reproduces in reverse form the solid body of the manufactured product.

The core 29 is usually made of pressed sand, preferably foundry sand, and binders, and this core is made by joining two half-core flasks obtained in the corresponding formwork half-molds by a molding method similar to that described above for the manufacture of clay formwork.

Alternatively, the core may be made of a material that can be easily removed after casting, for example, such as polystyrene.

7B shows an example of gravity casting. Therefore, the upper formwork half-mold contains the sprue channel 32 and the air outlet channels 33, completely similar to those shown in Fig.2B and described above.

On figs, 7C shows the formwork for the manufacture of the same product, which is shown in figa, with the only difference being that in this case, siphon molding is carried out. The same positions indicate the same details as in the case of the formwork and core shown in figv.

It should be noted that the method corresponding to the present invention allows the manufacture of a hollow concrete product of any type, having at least one hole providing communication between the inside of the product and the external space and having a non-linear shape, that is, a product from which it would be impossible to extract core that cannot be crushed.

It is also possible by the aforementioned method to produce concrete products with fixed metal rods (reinforced concrete products) by suspending metal fittings in a formwork form, if desired, and by pouring concrete. Similarly, it is possible to produce any composite products that require the insertion of fixed rods made of various materials - either metals or plastics, for example, heat or sound insulating materials, or materials that reduce weight.

From the foregoing description it follows that the method according to the invention has many advantages over known methods.

First of all, the replacement of conventional forms with pressed clay or sand formwork with binders dramatically reduces maintenance costs and the time required to carry out the whole process.

Since the proposed method can be carried out in a continuous cycle using the known automatic installation for molding clay formwork in sequential mode, followed by casting into formwork that can be moved on a conveyor belt, this contributes to the maximum productivity of the installation. As an example, we note that for the production of curbstones of freeways, it would be possible to provide for the production of formwork forms, each of which contains prints for 6 molded products, and an automatic machine that can produce 300/500 formwork forms per hour, which guarantees the production of 1800 / 3000 cast products per hour. This corresponds to a productivity 3-5 times higher than that achieved with conventional technology.

An additional advantage is that concrete is less likely to adhere to clay than metal, from which molds are usually made. This has the consequence, on the one hand, that it is possible to avoid the treatment with released chemical additives necessary for the manufacture of molds, and on the other hand, that it is possible to manufacture products that are better processed at the finishing stage than conventional products, in particular in the areas of corners and edges or at the stage of precise artistic processing.

Naturally, only specific embodiments of the concrete casting method of the present invention are described, and one skilled in the art will be able to make any modifications necessary to adapt this method to specific applications, but which are within the scope of protection of the present invention.

For example, in the installation shown in FIG. 1, more than one nozzle may be provided for pumping concrete. In addition, the nozzle or nozzles can also be arranged with the possibility of both gravity casting (as shown in the drawing) and siphon casting.

Claims (23)

1. A method of manufacturing concrete products, in which concrete is poured into at least one formwork form, from a material that can be compressed by compression and then crushed, wherein said formwork form comprises an upper formwork half-mold (8B ′) and a lower formwork half mold (8B "), the lower formwork half mold (8B") containing the imprint of a part of the product, and the upper formwork half mold (8B ') containing the complementary part of the product and the sprue channel (9), consisting of one or more sprues for gravity casting and one or b Lee air discharge channel (10). 2. A method of manufacturing concrete products, in which concrete is poured into at least one formwork mold made of a material that can be compressed by compression and then crushed, wherein said formwork mold contains an upper formwork half-mold (8C ') and a lower formwork half-mold (8C "), wherein the lower formwork half-form (8C") contains the imprint of a part of the product and the gating channel (9), consisting of one or more gates for siphon casting, and the upper formwork half-form (8C ') contains the complementary part of the product and one or more air outlets (10). 3. The method according to claim 1 or 2, characterized in that the formwork made of a material that can be sealed is crushed mechanically. 4. The method according to claim 1 or 2, characterized in that the material that can be densified by compression is selected from the group consisting of molding clay, other suitable mixtures of clay and sand, possibly mixed with suitable fillers. 5. The method according to claim 1 or 4, characterized in that it includes the following process steps, in which a) form one formwork or a plurality of formwork forms sequentially from a material that can be compacted by compression, preferably from molding clay, or other suitable clay mixtures, or from sand, these formwork forms reproducing the manufactured product in reverse form, b) intermittently or continuously pouring concrete into at least one formwork, c) ensure the solidification of the product in the formwork form or in each formwork form sequentially, d) release the product from the formwork or from their combination sequentially and, optionally, e) carry out finishing processing of the product. 6. The method according to claim 5, characterized in that the molding step includes the following process steps, in which i) prepare the model (2), reproducing in reverse form the manufactured product, ii) attach the model (2) to the plate (3) inside the flask (5), iii) tamping a material that can be compacted by compression in a flask (5), applying sufficient pressure to compact said material to form a formwork (8), iv) the formwork (8) is removed from the flask (5). 7. The method according to claim 1 or 2, characterized in that the concrete is cast concrete, preferably quick setting concrete for castings or similar products. 8. The method according to claim 7, characterized in that the concrete is SCATTO® concrete from ITALCEMENTI. 9. The method according to claim 5, characterized in that the stage of solidification of the product in the formwork is continued for a period of time varying from 30 to 90 minutes 10. The method according to claim 5, characterized in that the stage of releasing the product from the formwork is carried out by vibration, pressure, shaking or impact. 11. The method according to claim 5, characterized in that the stage of finishing processing of the product involves one of the following operations: stripping, trimming and sandblasting. 12. The method according to claim 11, characterized in that the stripping operation is carried out by brushes, or by means of jets of compressed air, or jets of water under pressure. 13. The method according to p. 12, characterized in that the trimming operation is carried out manually or by means of suitable machines or robots. 14. The method according to claim 11, characterized in that the sandblasting operation is carried out by exposing the surface of the product under pressure with jets of sand with compressed air or with water. 15. The method according to claim 1 or 2, characterized in that the product is a hollow concrete product having at least one hole providing communication between the inner and outer surfaces of the product and having a non-linear shape, and wherein the formwork contains an upper formwork half-form (28 ') and lower formwork half-form (28 "), moreover, these formwork half-forms after connection with each other limit the print corresponding in the reverse form to the outlines of the manufactured product, and in the cavity, which is limited the volume of the print, the core (29) is enclosed in the proper position, reproducing in the reverse form the cavity in the manufactured product, while the core (29) contains at each end of the support (30 ', 30 ", 30'"), which are located in the corresponding saddles formed in the formwork half-molds to keep the core suspended in a position suitable for receiving a cavity in the product, and between the core (29) and the inner walls of the imprint cavity there is a space (31) for pouring concrete, reproducing in solid form a solid body zgotavlivaemogo products. 16. The method according to p. 15, characterized in that the core (29) is made of pressed sand, preferably foundry sand, and is made by connecting two half-hearth flasks obtained using the corresponding formwork half-molds. 17. The method according to p. 15, characterized in that the core (29) is made of a material that can be easily removed after casting, preferably from polystyrene. 18. The method according to claim 1 or 2, intended for the manufacture of products with reinforcement - fixed metal rods, characterized in that it includes the stage at which the metal reinforcement is placed in the formwork, and then concrete is poured. 19. The method according to p. 18, characterized in that they use a fixed rod made of various materials, preferably plastics, instead of the fixed metal rod. 20. The method according to claim 19, characterized in that the said fixed rod is made of heat or sound insulating materials or materials to reduce weight. 21. A concrete product that can be manufactured by the method according to claim 1 or 2. 22. The product according to item 21, selected from the group consisting of curb stones of motorways, railway sleepers, well covers - concrete support rings and manhole covers, building blocks of all types and shapes - solid, with cavities or with open cross sections, pipes all shapes and sizes, skirting boards, art products of all shapes and types, such as statues, garden benches, vases and artificial cobblestones, blocks for “untreated” pavers (17), balances (19) or ballast, as well as tile tiles (23) . 23. The product according to item 21, which is a hollow concrete product having at least one hole that provides communication between the inner and outer parts of the product and having a non-linear shape.

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