EP0890422A1 - Process for casting articles , in particular decorating articles from plaster or concrete and device for carrying out the process - Google Patents

Abstract

A method for producing mouldings, especially ornaments made of plaster or concrete, involves locating the moulds in a low pressure chamber (1) and drawing off the air from the liquid plaster or concrete moulding material, so that smooth mouldings (25) are formed. The pressure is preferably 0.6-0.8 bar and the moulds (2) consist of an outer single or multi-part box with a silicone insert.

Description

The invention relates to a method for casting castings, in particular of decorative elements made of plaster or concrete according to the generic term of Claim 1, and an apparatus for performing the method according to the preamble of claim 4.

The production of decorative elements made of plaster, such as stucco elements, Figures, etc. are usually done by hand. Stucco elements, for example stucco rosettes or stucco moldings are in Open top molds made by pouring liquid gypsum into the molds and smoothed or smoothed on the free surface. Known casting molds consist of a stable outer mold box, in the silicone inlays in the negative form of the desired casting be inserted. Divisible, closed are also used for the production of figures Casting molds with pouring and overflow openings known.

These artisanal casting processes are time-consuming and costly. In addition, air is trapped when mixing and pouring liquid gypsum, which when hardening to pores in the material and especially Zu Surface defects as recesses, pores and depressions on the finished Cast body leads. Such surface defects represent an optical one This is a defect that may be elaborately reworked, particularly with stucco elements must become. Such surface defects are also dirt traps and points of attack for surface destruction due to environmental influences.

Due to the craftsmanship and the pore inclusions only relatively thick walls are possible in the casting material, which leads to a high material consumption and heavy castings. Hollow cast body cannot usually be produced.

It is also known to use castings as artistically designed components, for example Columns, figures, banisters etc., made of concrete. The concrete is preferably made of quartz sand, granite sand or marble powder and primarily white Portland cement.

These concrete castings are also similar to those described at the beginning Cast body made of plaster, in principle, here too Disadvantages of the high weight with large wall thicknesses and porous surfaces as well as pore inclusions occur. The danger of extensive, considerable Surface defects are still due to the granular structure of the concrete larger than with plaster castings.

There are already a method and an apparatus for producing large format Components made of concrete are known [DE-AS 2 054 983]. It is under Use a closed mold in this after creating a Vacuum and opening a concrete filler neck at high speed sucked in due to the vacuum. Here vacuum becomes immediate produced in a complex manner in the completely closed form. The Vacuum is only used to suck in and compress the liquid that is sucked in Concrete used, with possible air pockets in the liquid concrete in the mold and thus in and on the cast body as pores and surface defects remain. In addition, the high suction speeds the inner wall area of the mold is heavily loaded, so that finely structured Designs using silicone mold inserts are not possible here. This is the process for the production of Decorative elements, especially not suitable in smaller series.

Next is a process for the production of hollow beams, piles or the like is known from concrete [DE-OS 27 47 065], in which in the longitudinal center an inflatable tube is inserted into a mold. This method is a simple, elongated hollow body for mass production usable, but for the production of decorative elements in small series with varying design forms too expensive.

The object of the invention is to provide a method for casting castings, in particular of decorative elements made of plaster or concrete and a device to provide for the implementation of the method, wherein such castings inexpensively in industrial processing with high Product quality can be produced.

This task is carried out with regard to the method with the features of Claim 1 solved.

According to claim I, the casting process is carried out in a vacuum Vacuum chamber in which molds are set. Here turns from liquid gypsum or concrete to liquid during the pouring process Air contained in the casting material is extracted, creating a non-porous casting can be produced.

Dense, firm and smooth surfaces are thus obtained with an optical good overall impression. Small structured parts are advantageous fully filled. The smooth surfaces may make it easier Paint application and coatings possible without preparatory work. The smooth ones Surfaces are particularly important when setting up castings in the free, as with pillars, banisters, etc. largely resistant to Environmental influences and weatherproof.

This process is suitable for both casting castings from plaster can also be used advantageously in concrete. Because of the non-porous Casting achieves a dense material structure of high strength, so that compared to castings made with conventional methods Wall thicknesses can be reduced. So that the cost of materials and that Weight of the cast body can be reduced, which is particularly the case with large format Castings for easier processing and reduction of transportation costs. In addition, stable hollow castings are included inner ribs that improve stability are possible. The hollow castings can, if necessary, become viable, heavy-duty at their final installation location Components continue to be poured with concrete.

The production of the castings is by the method according to the invention using machinery and using a variety of Parallel forms are possible on an industrial scale at low cost. Across from the previous imprecise manual work with irregular, porous surfaces high-quality components and decorative elements can be manufactured.

It has been shown that a relatively small, easily and quickly generated Vacuum in the vacuum chamber is sufficient to the above to achieve cleared pores. According to claim 2 is a preferred Vacuum pressure of 0.6 to 0.8 bar.

The casting process is used in conjunction with a plurality of molds easy to carry out by according to claim 3 to the individual molds Movable casting material distributor in the vacuum chamber is provided. In addition, the supply connection is liquid casting material sealed airtight, so that the negative pressure in the vacuum chamber during the entire casting process is maintainable.

The object of the invention with respect to the device Features of claim 4 solved.

According to claim 4 is an openable for setting molds and airtight closable vacuum chamber provided with at least a connection for at least one vacuum pump and with at least a feed connection for feeding liquid casting material. A such a vacuum chamber can be constructed with simple means and inexpensively operate. The dimensioning of the vacuum chamber depends on the size and number of molds used.

According to claim 5, the feed connection for the liquid casting material comprises advantageously arranged outside on a ceiling wall of the vacuum chamber Filling funnel, the funnel outlet of which is airtight in the vacuum chamber guided and through a flexible hose as a casting material distributor is extended. The end of the hose becomes practical provided with a closure device so that a dosed, successive Filling individual molds is possible. Depending on size the arrangement and the casting materials used, it can be advantageous be, especially to accelerate the material transport the hopper to vibrate against the fixed vacuum chamber.

For simple and quick manipulations in the vacuum chamber is proposed with claim 6, this as a glove chamber known per se with airtight connection, reaching into the chamber volume Gloves.

Since the molds themselves are not evacuated directly, for the pore-free casting according to the invention, known per se, on a Top open molds can be used according to claim 7. In the However, use of such molds is also a distribution and the casting material must be removed by hand from the free upper side.

A major improvement in terms of industrial manufacturing therefore the two-part closed also specified in claim 7 Casting molds from a lower mold and an upper mold, the Upper form has a filler neck and an overflow neck. Also such molds are not evacuated directly, but are over the open filler neck and overflow neck with the vacuum in the Vacuum chamber applied. For a quick, even by assistants pouring process that is easy to carry out, it is only necessary here to put the filler hose on the filler neck and so long material fill in until it begins to emerge in the overflow nozzle.

According to claim 8 are known per se, the negative form of the Casting body-reproducing silicone inserts can be used because the mold is mechanically stressed even during the casting process.

When using two-part, closed molds for production of relief shapes, especially rosettes, can be made on simple Way the flat backs executed with a concave curvature become. This is advantageously achieved that when gluing this flat Backs on flat walls do not have excess adhesive in one Gap between the back and the wall emerges, which is too expensive Reworking leads. Such relief shapes as stucco elements with concave Back curvatures are therefore particularly simple and clean process, making such elements especially from craftsmanship Inexperienced people can be processed in a do-it-yourself process can.

For the production of longer, hollow castings, in particular columnar ones Castings with bulges are proposed according to claim 10, to use an outer, two-part pouring box with one that outer negative form of the cast body reflecting silicone insert. In addition, a flexible stocking is used that can be filled with bulk goods is and then in its shape an inner cavity of the cast body limited. An inner bar is also used, which is in the stocking is plugged in continuously and at least upwards out of the mold protrudes.

To prepare the pouring process, the unfilled stocking is covered with the inserted inner rod in the mold in an approximately vertical arrangement inserted and then the stocking with preferably granular material filled, this filling also through pipe wall openings tubular inner rod can be made. This creates a space made according to a cast body wall thickness, from above is filled with liquid casting material. During this pouring process, the here preferably also in a vacuum chamber, but with good ones Casting results can also be done without a vacuum chamber Inner rod vibrates when the casting box is stationary. It has been shown that particularly good non-porous casting results with good material transport in the Interspace with a relatively high vibration frequency of approx. 2000 to 10000 Hz can be reached, these frequencies being significantly higher than The usual compressor frequencies of concrete vibrators are. After a certain Solidification time is preferred, the filling material from the stocking let down and this and the inner rod from the Removed interior of the cast body. After opening and removing the For example, a thin-walled pillar is thus produced from the outer molded parts. The stocking can according to claim 11 with outer longitudinal webs be provided, which then corresponding reinforcing longitudinal webs on the inner wall of the cast body.

Such hollow pillars are relative because of their light weight and their high strength easily transportable and for example on construction sites easy to set up. Such pillars with structural steel mesh are then preferred reinforced in its interior and poured with concrete in the usual way, so that they then result in stable and heavy-duty supports. The hollow column parts made with the casting process have it on the one hand the function of a concrete formwork and on the other hand the function a high-quality column surface that has been manufactured right from the start. With These measures can, for example, be viable and highly resilient Columns of different optics can be manufactured easily and inexpensively, the otherwise with considerable costs and usually with lower quality with a regular shape and a smooth surface could only be made by hand.

Correspondingly, for example, balustrades and banisters are made from hollow parts, the cavities of which when building the hollow parts are connected together and then for production of a stable, one-piece building can be sprayed with concrete.

The method according to the invention and the proposed devices are excellent for simple and inexpensive, as well as high quality Manufacture of decorative elements, in particular stucco elements and also suitable for the concrete column production described above. However, the problems of porous, uneven surfaces also occur with the Production of flat concrete components, such as ceiling elements, Exposed concrete walls, noise barriers etc. This leads to such components on their visible side regularly after laying to achieve have to be filled and sanded on a smooth surface. This represents a considerable effort, especially if such as ceiling surfaces for a high quality look be prepared for attaching stucco elements in this way have to.

Also for the production of such large-area concrete components Visible surfaces is the method according to the invention for achieving smooth, dense surfaces can be used advantageously. As a device for this, after Claim 12 proposed a vacuum chamber as a removable hood to train. This means that conventional production facilities can be controlled airtight placement of the hood on an assigned lower part or be subjected to negative pressure on the floor, which also means here a non-porous casting with dense, smooth surfaces and possibly reduced Wall thickness is possible. Reworking with spatulas and As a rule, loops can then be omitted.

The invention is explained in more detail with reference to a drawing.

Fig. 1

eine schematische Darstellung einer Unterdruckkammer als Handschuhkammer mit eingestellten Gießformen und einer Zuführeinheit,

Fig. 2

einen Schnitt durch eine Gießform gemäß Fig. 1,

Fig. 3

einen Schnitt durch einen mit der Gießform nach Fig. 2 hergestellten Gußkörper als Stuckrosette, die an eine Raumdecke geklebt ist,

Fig. 4

einen Vertikalschnitt durch eine Gießform zur Herstellung einer hohlen Säule, und

Fig. 5

einen Horizontalschnitt durch die Hälfte der Gießform nach Fig. 4 entlang der Linie A-A.

Show it:

Fig. 1

1 shows a schematic representation of a vacuum chamber as a glove chamber with set molds and a feed unit,

Fig. 2

2 shows a section through a casting mold according to FIG. 1,

Fig. 3

2 shows a section through a casting made with the casting mold according to FIG. 2 as a stucco rosette which is glued to a ceiling,

Fig. 4

a vertical section through a mold to produce a hollow column, and

Fig. 5

a horizontal section through half of the mold of FIG. 4 along the line AA.

In Fig. 1 is an apparatus for performing a method for Casting castings, in particular decorative elements made of plaster or Concrete shown schematically. This device includes an airtight one lockable vacuum chamber 1, into the closed molds 2, which each have a filler neck 5 and an overflow neck 6, are set. For setting molds 2, the vacuum chamber comprises 1 e.g. one or more airtight closable opening flaps or doors, which are not shown in FIG. 1.

On the outside of a ceiling wall 7 of the vacuum chamber 1 is a Feed connection 8 is formed for liquid casting material 17, to which a funnel 10 is connected airtight. A funnel outlet 9 of the hopper 10 is guided into the vacuum chamber 1 and through a flexible Hose 11 extended as a casting material distributor.

This flexible hose 11 has a closure device at a hose end 12 13 for a metered filling of the individual casting molds 2 on. 1, the hose end 12 is on the filler neck 5 of the casting mold 2 to be filled.

For easy and quick handling of the flexible hose 11 in the vacuum chamber 1 is designed as a glove chamber. For this purpose, from a chamber outside of the vacuum chamber 1 in the chamber volume 14 reaching gloves 15 connected airtight. In the schematic representation of FIG. 1 there are only two Such gloves 15 shown as an example. However, it can also more than two gloves 15 are arranged on the vacuum chamber 1 be. The handling of the hose 11 during a casting process can through viewing windows, also not shown here, e.g. on the side walls of the chamber, controlled and tracked.

There is also a connection in the area of the ceiling wall 7 of the vacuum chamber 1 18 provided for a vacuum pump 19 with which a vacuum of preferably 0.6 to 0.8 bar can be generated in the vacuum chamber 1 is.

As can be seen in particular from FIG. 2, the section through 3 is a mold 2 for a rosette 25 shown in FIG Mold 2 closed in two parts with an upper mold 3 and a lower mold 4 trained. The upper form 3 consists of a stable upper box 20, in which a silicone insert 22 is inserted. This silicone insert 22 there a negative form 24 of a concave curvature 26 [cf. Distance D) as flat Back of rosette 25 again. The lower mold 4 also consists of a stable lower box 29, in which a silicone insert 23, which is a negative form 21 shows a visible side of the rosette 25, is inserted. Out Fig. 3 is evident that the concave curvature 26 on the back the rosette 25 they are glued to a flat ceiling wall 27 in this way that there is no excess adhesive 28 between the back of the rosette 25 and the ceiling wall 27 emerges.

The process for casting decorative elements from plaster or concrete is now described below with reference to FIGS. 1 and 2:

In a first step, with the vacuum chamber 1 open, the desired ones Number of molds 2 set in the vacuum chamber 1. The vacuum chamber 1 is then sealed airtight and supplied via the hopper 10 liquid casting material 17. Here the flexible hose 11 is operated by an operator using the glove 15 gripped and the hose end 12 on the filler neck 5 each to be filled mold 2 placed.

Now the closure device 13 is opened at the hose end 12, so that the liquid casting material 17 via the filler neck 5 into the interior the mold 2 to be filled can flow. To accelerate material transport the hopper 10 is opposite the fixed vacuum chamber vibrates, as indicated in FIG. 1 with the double arrows 16 is. The casting material 17 is filled into the casting mold 2 as long as until it begins to emerge from the overflow nozzle 6, what the operator is checked via a viewing window. As soon as the casting material 17 over the Overflow nozzle 6 emerges, the operator closes the closure device 13 and puts the hose end 12 on the filler neck 5 of the next Mold 2 where the whole process is repeated.

During the casting process, a vacuum is created via the vacuum pump 19 generated in the vacuum chamber 1, the molds 2 not be evacuated directly, but via the open filler neck 5 and Overflow nozzle 6 are subjected to the negative pressure. By the Vacuum in the vacuum chamber 1 becomes from the liquid casting material Extracted air so that non-porous castings with smooth, non-porous Surfaces emerge. Due to the constant flow of liquid Casting material 17, the feed connection 8 is sealed airtight, so that the vacuum in the vacuum chamber 1 throughout Pouring process is maintained.

After filling all in the vacuum chamber 1 Casting molds 2, the vacuum pump 19 is switched off, the vacuum chamber 1 opened and the molds 2 removed.

This process is also used in the production of large-scale concrete building elements, such as. Ceiling elements, exposed concrete walls, noise barriers etc. can be used to achieve smooth, dense surfaces. This is the vacuum chamber 1 designed as a removable hood, which is controlled by an assigned Vacuum applied to the lower part or to the floor can be put on.

4 is an alternative mold 30 for producing a hollow one Column shown, of which at least one also in the vacuum chamber 1 is adjustable. This mold 30 comprises a two-part, stable casting box 31, of which only one half is shown here. In this casting box 31, a silicone insert 32 is used, the outer Negative form of a hollow column.

The casting mold 30 further comprises a flexible stocking 33, which contains bulk material can be filled from granular material. This flexible stocking 33 limits an inner cavity of a hollow when filled Pillar. An inner rod 34 is continuous in the flexible stocking 33 inserted, which protrudes on two opposite sides of the mold 30. The flexible stocking 33 is at its ends in the area of the Starting from the mold 30 e.g. with a strap 37 fixed and releasably held on the inner rod 34.

To prepare the pouring process, the unfilled stocking 33 with the inserted inner rod 34 in the two-part casting box 31 approximately inserted vertically and then the stocking 33 with granular material 35 filled. The filling can e.g. through wall openings 40 (only a few shown) of a tubular inner rod, which is filled from its upper pipe opening. This will make a Gap 36 made according to a cast wall thickness. In this space 36 is on a funnel-shaped projection 38 poured liquid casting material 17 into the upper region of the casting box 31. To achieve good material transport into the intermediate space 36 the inner rod 34 with a fixed casting box 31 with a frequency vibrates from approx. 2000 to 10000 Hz. One in the vacuum chamber 1 by means of the vacuum pump 19 produces vacuum in an analogous manner to the method described in connection with FIGS. 1 and 2 that the liquid casting material 17 air to create a non-porous hollow Pillar is withdrawn.

Then, for example, after a certain solidification time one of the straps 37 loosened and the granular filler 35 from the flexible stocking 33 let out. Then the flexible stocking 33 together with the inner rod 34 from the interior of FIG. 4 removed, not shown, now solid hollow column. Thereupon the pouring box 31 is opened and the pore-free, thin-walled column taken.

As can be seen in particular from FIG. 5, the horizontal section through mold 30 along line A-A of FIG. 4 the flexible stocking 33 is provided with outer longitudinal webs 39. Thereby are in a hollow column according to reinforcing longitudinal webs Improved stability. Be at the final site the pillars are then reinforced with mild steel mesh in their interior poured with concrete so that they have stable and heavy-duty supports surrender.

Claims (12)

Process for casting castings, in particular decorative elements made of plaster or concrete,
characterized,
that the casting process takes place in a vacuum chamber [1] pressurized, into which the casting molds are set, the air contained therein being removed from the liquid gypsum or liquid concrete as liquid casting material [17] during the casting process, so that pore-free casting bodies [25] in particular can be produced with smooth, non-porous surfaces. A method according to claim 1, characterized in that the vacuum Is 0.6 to 0.8 bar. Method according to claim 1 or claim 2, characterized in that that the liquid casting material [17] through a into the vacuum chamber [1] reaching and there to individual molds [2; 30] movable feasible pouring material distributor [11] into the casting molds [2; 30] filled becomes. Device for carrying out one of the methods according to claims 1 to 3, characterized in that
that one for setting molds [2; 30] openable and airtightly closable vacuum chamber [1] is provided, with at least one connection [18] for at least one vacuum pump [19] and with at least one supply connection [8] for supplying liquid casting material [17] into at least one into the vacuum chamber [ 1] adjustable mold [2; 30]. Device according to claim 4, characterized in that the feed connection [8] for the liquid casting material [17] one on the outside Ceiling wall [7] of the vacuum chamber [1] arranged, if necessary opposite the stationary vacuum chamber [1], the feed hopper can be vibrated [10] comprises the funnel outlet [9] airtight in the vacuum chamber [1] managed and preferably by a flexible Hose [11] is extended as a casting material distributor. Device according to claim 4 or claim 5, characterized in that that the vacuum chamber [1] as a visible and openable glove chamber with airtightness reaching into the chamber volume [14] connected and can be tightened from the outside of the chamber Gloves [15] is formed. Device according to one of claims 4 to 6, characterized in that the molds which can be used in the vacuum chamber [1] are molds which are known per se and are open at the top, and / or
that the molds [2] that can be inserted into the vacuum chamber [1] are formed in two parts, closed with a lower mold [4] and with an upper mold [3], with at least one filler neck [5] and overflow nozzle [6] on the upper mold [3]. Device according to claim 7, characterized in that the casting molds [2] an outer one-part or multi-part, stable pouring box [20, 29] have the negative form [21, 24] of the cast body [25] reflecting sillcon insert [22, 23]. Device according to one of claims 4 to 6, characterized in that
that the casting molds [2] are designed for the production of relief molds, in particular rosettes [25], the casting molds [2] having a flat rear side [26] being attachable to a wall [27] by means of an adhesive [28], and
that the back [26] has a concave curvature. Device with a casting mold for casting longer, hollow cast bodies, in particular columnar cast bodies with bulges, in particular in connection with a device according to one of claims 4 to 6,
marked by an outer, at least two-part casting box [31], a silicone insert [32] reflecting the outer negative shape of the cast body, a flexible stocking [33] which can be filled and then delimits an inner cavity of the cast body, and an inner rod [34], which is contained in the stocking [33] and protrudes at least upwards out of the casting mold [30], whereby to prepare the pouring process, the unfilled stocking [33] with the inserted inner rod [34] is inserted into the casting mold [30] in an approximately vertical arrangement, the stocking [33] is filled with preferably granular material [35], if necessary, through wall openings in a tubular inner rod, whereby the assumed, predetermined shape of the filled stocking [33] leaves a gap [36] as the cast wall thickness for the silicone insert [32], the space [36] is filled with liquid casting material [17] from above and the inner rod [34] is vibrated when the casting box [31] is stationary, preferably with a frequency of 2000 Hz to 10000 Hz, and after a predefinable solidification time, the filling material [35] from the stocking [33] is preferably emptied downward and this and the inner rod [34] are removed from the interior of the cast body. Apparatus according to claim 10, characterized in that the Stocking [33] on its outside has longitudinal webs [39] which on the Corresponding reinforcing longitudinal webs result in the inner wall of the cast body. Device according to one of claims 4 to 6, characterized in that that preferred for the production of large components such as ceiling elements the vacuum chamber [1] an upper part as if necessary Controlled detachable hood that is airtight on an associated Bottom part for creating a negative pressure during the casting process is attachable.

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