WO1982003348A1

WO1982003348A1 - Method and device for pneumatically compacting molding sand

Info

Publication number: WO1982003348A1
Application number: PCT/DE1982/000080
Authority: WO
Inventors: Maschf Gmbh Badische
Original assignee: Koebel Alfons; Damm Norbert
Priority date: 1981-04-02
Filing date: 1982-04-02
Publication date: 1982-10-14
Also published as: EP0062331A1; JPS58500474A

Abstract

In the method of pneumatic compacting of molding sand in molds with a molding cavity closed and delimited by the model, the cavity is first filled with sand and set under pressure at a pressure gradient comprised between 100 and 1000 bar/s. The absolute pressure before and after exposure to the pressure is comprised between 0.8 and 8 bars, so that exposure to pressure is effected within milliseconds. It is thereby possible to obtain a high and uniform mold hardness with minimum construction means and with a reduced energy and air supply. Alternatively, the sand introduced in the molding cavity may be exposed to a vacuum comprised between 0.4 and 0.2 bar, and then the free surface of the sand may be subjected to a compressed air jet up to 15 bars. The jet has a supersonic speed. A device for implementing this method comprises a molding cavity (1), a jet opening (7) and a closure (11) for that opening.

Description

Method and device for the pneumatic compression of molding sand

The invention relates to methods for the pneumatic compression of the molding sand of foundry molds, which is enclosed in a closed mold space, the boundary of which is formed by a model encased by the molding sand, and devices for carrying out these methods.

Known pneumatic compression methods mostly work on the shooting principle. Here, a metered amount of molding sand in the form of a plug is injected or blown into the empty, closed mold space. Injecting the molding sand is particularly common for the actual molds, while the BJas process is used in particular for core molds that do not get their final hardness directly through the compression process, but through the addition of appropriate binders. In the case of molds, however, such binders are particularly in Higher proportions are undesirable because of the difficulties in processing the old sand, so that here the compaction is achieved by the shooting process itself and the high pressure used. It is also known to produce the inclusion of the molding sand in the mold cavity not by compressed air acting on the molding sand plug, but by placing the empty molding space under vacuum and then opening it to the filling vessel, so that the molding sand under the effect of the atmospheric pressure on it is shot in the mold space. In addition, combined processes are known in which the molding space is evacuated with excess pressure before and / or while the molding sand is being shot in, but the vacuum primarily serves to remove the excess firing air from the molding space as quickly as possible and thus the Prevent formation of air cushions or air pockets in the molding sand (e.g. DE-OS 27 27 297).

Finally, it is known (DE-AS 28 44 464) to shoot the molding sand onto the model and thereby achieve pre-compression and then to apply compressed air blasts of up to 7 bar to the free molding sand surface for a period of less than 1 second. Here, however, post-compression of the mold by mechanical pressing is required, the mold being evacuated even during the pressing process.

The energy expenditure and the air requirement in the known methods are quite considerable, without it having been possible to achieve sufficient hardness with this purely pneumatic compression. In addition, the expenditure on equipment is considerable in all cases. The invention has for its object to provide pneumatic compression methods that manage with the least possible effort with a comparatively low energy and air requirement, with a high and uniform mold hardness is to be achieved.

This object is achieved according to the invention in a first variant in that the molding space filled with the molding sand is pressurized with air at a pressure gradient of greater than 100 bar / s up to 1000 bar / s. The pressure difference before and after filling the mold space is advantageously between 0, 8 and 8 bar.

The method according to the invention has the great advantage over known methods. that the molding space is first filled with molding sand using conventional simple means and the compression takes place exclusively by the sudden application of air to the molding space. It is important that the pressure builds up in the range of milliseconds, whereby the existing absolute pressure of up to 8 bar can be easily mastered constructively - Practice has shown that it is not - as would be assumed - to the highest possible absolute pressure, but exclusively, the greatest possible pressure gradient is important, ie the overpressure must be brought into effect in the shortest possible time. In practice, this can be achieved in the simplest way by suddenly connecting the molding space filled with molding sand, which is under normal pressure, to a compressed air reservoir.

It has proven to be advantageous if the flow of the air flowing into the mold space is directed approximately perpendicular to the surface of the molding sand, even if satisfactory results can be achieved with a different flow direction. A second variant for solving the object of the invention is based on a known method for compacting foundry molding material in an evacuable molding space in which the filled molding material is placed under negative pressure. The solution according to the invention is that compressed air of up to 15 bar is applied as a free jet to the free surface of the molding material. The kinetic energy of the free jet is converted into a compressive force acting on the back of the mold when it hits the free surface of the mold, the compressed air penetrating into the mold material being able to relax freely on the one hand because of the prevailing vacuum, and on the other hand supporting the press action by ruining the mold material.

Preferably, the procedure is such that the molding space is first filled with the molding material, then evacuated to 0.4 to 0.2 bar and then the compressed air free jet is brought into effect. In other words, the evacuation and pressing by means of a compressed air jet take place at different times. It is advantageous if the vacuum is maintained during the free jet pressing and thus a high pressure drop between the back of the mold and the shaped surface. This counteracts in particular the risk that pressure bubbles will form when the compressed air penetrates the molding material.

With lower demands on the form stability, the process can also be carried out in such a way that the mold space is evacuated to 0.4 to 0.2 bar, then filled with the molding material and the compressed air free jet is brought into effect on the free surface of the molding material. The molding material is therefore accelerated into the evacuated molding space due to the pressure drop and pre-compressed when it hits the model and the compressed air jet is activated during the incidence of the molding sand or after the filling process has ended. In a preferred embodiment of the invention, the compressed air free jet has supersonic speed, since an optimal energy conversion is possible above this critical speed.

In order to increase the dynamic pressure at the free surface of the molding material, the height of which is decisive for the energy conversion, it is provided according to a further exemplary embodiment that the free surface of the molding material before the application of the compressed air free jet with a flow-increasing layer close to the surface Substance is covered- A further increase in the pressing effect is possible.

Liquids such as water, water-binder mixtures or plastic solutions, but also fine dusts, which do not interfere with the processing of the molding material, can be considered as substances.

A constructive solution of the first method variant is based on a device with a molding space that receives the molding sand, that of a model, a molding frame surrounding it, and a molding space closure on the model! opposite side is formed. Such a device is characterized in accordance with the invention in that the molding space is provided with at least one nozzle opening which opens outside the surface of the molding sand and a closure device associated therewith which allows a pressure build-up of faster than 100 bar / s in the molding space when opened. This pressure gradient can be achieved by appropriate dimensioning of the nozzle opening (s) and the closure device and its drive.

In order to be able to produce the desired pressure degree, it has proven to be expedient to connect the molding space to a pressure accumulator in the area free of molding sand via the nozzle opening. Of course, two or more nozzle openings can also be present, it being advantageous if the axis of each nozzle opening is arranged approximately perpendicular to the surface of the molding sand.

According to a preferred embodiment, the nozzle opening is designed as a Laval nozzle, so that a low-loss free jet flow is guaranteed, which can lie in the supersonic area and, due to the low formation of vortices, leads to the formation of an approximately flat spine.

In the case of larger molds, the same effect is achieved if each Laval nozzle is arranged and designed in such a way that the freϊ jets generated by it hit approximately the entire surface of the molding sand. This also ensures optimal implementation of the flow energy in suspicion work across the entire cross-section of the mold.

It has proven to be advantageous if the molding space in the region of the model is provided with outflow openings for the air, which are optionally also connected to a vacuum. This ensures, in particular if the absolute pressure or the amount of air is too high, that this does not impede the compression and can flow away.

It can also be advantageous if outflow openings are provided in the base of particularly deep model contours. This ensures that a high and constant form hardness is achieved even in the area of such deep model contours.

Further embodiments of this device are characterized in claims 21 to 31. A device-technical solution of the second method variant is based on a known device with a model plate carrier, an attached molding box, a Fulia attachment located above it and a closure plate, which together form the molding space, and with a filling vessel containing the molding material. Such a known device is characterized according to the invention by one or more free jet nozzle (s) opening into the molding space and connected to a compressed air source. The mouth cross section of the free jet nozzle (s) and the height of their arrangement above the free molding material surface must be such that the free jet is effective on the entire molding material surface. In order to achieve the speed of sound with such a free jet nozzle in the mouth cross section, it must have an opening angle of 10 to a maximum of 14 ° according to the rules of flow technology.

From a certain mold box size, the critical opening angle can only be achieved with very long nozzle lengths. In order to prevent the nozzle from becoming unacceptably long in the case of larger mold boxes, it is provided according to a further feature of the invention that the wall of the free-jet nozzle has openings which can be connected to a vacuum. With this measure, the opening angle of the

Free jet nozzle can be enlarged. Usually vortices will then already come off on the wall, preventing critical speeds from being reached. With the measure according to the invention, however, these eddies are suctioned off, so that despite a larger opening angle! can reach at least the speed of sound in the mouth cross-section. Due to the larger opening cross-section, it is then ensured that the free jet strikes the entire free molding surface. In one embodiment of the feature according to the invention mentioned above, the free jet nozzle has a double wall, and the space formed by the walls is provided with a vacuum connection. Here, the vacuum connection can lead to the same vacuum source to which the mold space is also connected.

As already indicated, it can be advantageous to increase the flow resistance of the layer of the molding material near the surface by spraying on a liquid. In terms of device technology, this is achieved in that a device for injecting the liquid onto the free molding material surface is arranged in the upper region of the molding space.

The methods according to the invention and the devices proposed for their implementation are suitable for final compaction, in which case static molding and / or stripping of the molding sand can be provided to level out the back of the mold. The method can also be used for the post-compression of any pre-compressed shapes, be it by shooting, blowing or the like. The method also has the advantage that the compression can take place independently of the direction, i.e. both from above and from below, but also in the horizontal position of the model. It is also possible to compress double-sided models from above and below at the same time.

The invention is described below with reference to some exemplary embodiments of the device shown in the drawing. The drawings each show a schematic longitudinal section: Figure 1 A first embodiment with flat nozzle for one-sided models;

Figure 2 shows a second embodiment with Laval nozzles for single-sided models;

Figure 3 shows a third embodiment with a lateral nozzle opening;

Figure 4 shows an embodiment for double-sided models;

Figure 5 is a schematic view of one after the second

Variant of the var proceedings device according to the invention in a first embodiment and

Figure 6 is a schematic view corresponding to Figure 1 of a second embodiment of this device.

The representations in FIGS. 1 to 4 show only a schematic section of otherwise conventional molding machines which are equipped with devices for filling the molding spaces, for positioning (moving in,

Pivoting, lifting and locking) of the mold plate and mold frame and for sealing the mold spaces. For a better overview, these facilities are not shown.

The molding space is formed laterally by a molding frame or molding box 1, an attached filling frame 2, on the underside by a model plate 3 with the model 4 and on the top by a closure 5. The end 5 is designed as a plate and with a nozzle opening 6 in shape a Rach nozzle 7 provided. At the same time, the plate 5 forms the lower end of a prechamber 8, which is connected to one or more pressure accumulators 10 via a large-sized nozzle 9.

In the pre-chamber 8 there is a closure device 11 which, in the exemplary embodiment shown, is designed as a poppet valve 12 which closes the flat nozzle 7 and interacts with the top of the end plate 5. The poppet valve 12 is equipped with a lifting drive 13 arranged outside the prechamber 8.

In the exemplary embodiments shown, the model plate 3 forms the upper end of an exhaust air chamber 14 into which excess air from the molding space can penetrate through outflow openings 15 in the model plate 3 and can be discharged via an exhaust air connector 16. Furthermore, in the exemplary embodiment according to Rgur 1, outflow openings 18 are also provided in deep contours 17 of the model 4 and also open into the outflow chamber 14. If necessary, a vacuum pump can be connected to the exhaust air connection 16. However, it is also possible to provide further vacuum connections on the molding frame or molding box 1.

If the filling of the molding frame 1 and the filling frame 2 does not take place outside the machine, the prechamber 8 can be pivoted about a vertical axis lying outside the molding space, so that the cross section of the filling frame 2 is free. In this position, the molding sand can then be filled in in an appropriately dimensioned amount until it reaches, for example, the fill level indicated by 19. The molding space is expediently dimensioned such that the free volume 20 above the molding sand surface 19 is as small as possible. Then the Antechamber 8 swung in and locked. Thereafter, the valve plate 12 is suddenly raised, so that at least some of the air contained in the compressed air reservoir 10 relaxes via the flat nozzle 7 into the molding space and thereby compresses the molding sand by a combination of dynamic pressure and jet pressure. The cross section of the flat nozzle 7 and the valve plate 12 and its drive 13 are dimensioned such that the pressure build-up in the molding space takes place at greater than 100 bar / s. With appropriate dimensions, this can be achieved with an absolute operating pressure of up to 8 bar, which is still below the usual compressed air network pressure. Due to the extremely short compression time, which is in the millisecond range, the energy required for compression is very low compared to other known methods. For example, the amount of air required for a mold box of customary dimensions of 800 × 650 × 300 mm is approximately 1.3 kg or 1.5 Nm ³ per molding process. As always desired, particularly high model densities are achieved on the model contours, which decrease slightly towards the back of the mold, but are completely sufficient for the further process steps.

After compaction, the level 19 of the molding sand drops to the area of the upper edge of the molding frame or molding box 1. The top layer, a few millimeters high, is - apparently due to fluidization effects - formed by loose molding sand, which can either be stripped or leveled out by a pressing process.

The execution example! 2 differs from that of FIG. 1 essentially only in that two or more Laval nozzles 20 are provided as the nozzle opening 6, the mouths of which are approximately flush with the

Bottom of the top end plate 5 ends. The inflow openings 21 the Laval nozzles 20 are in turn assigned a closure device 11 in the form of a poppet valve 22 which closes all the Laval nozzles present at the same time. With these Laval nozzles, a low-loss and vortex-free conversion of the pressure energy into kinetic energy is possible. In addition, the compressed air jet diverges during relaxation, so that the molding sand is applied more evenly. The supersonic speed that can be achieved with a Laval nozzle is also manifested in an increased dynamic pressure when the air jet strikes the surface of the sand, which leads to even better dimensional stability.

In the exemplary embodiments shown in FIGS. 1 and 2, the axis of the nozzle openings is approximately perpendicular to the surface of the molding sand. Deviating from this, Rgur 3 shows an exemplary embodiment in which the upper end plate 5 of the molding space has a relatively large opening 23 to the prechamber 8. The nozzle opening 6 is arranged in a side wall 24 of the prechamber 8 and is provided, for example, with a pivotable closure device 11. When the closure device 11 is opened, the compressed air from the reservoir 10 relaxes via the nozzle opening 6 first into the prechamber 8 and only then into the molding space. Even if the jet pressure is not involved in the compression process, satisfactory mold hardness can be achieved. This embodiment facilitates the filling of the molding sand and - if necessary - the re-compacting in a single work station within the molding machine, since the pre-chamber 8 can be designed or moved in a simple manner so that the molding space is freely accessible.

Finally, Rgur 4 shows a design example in which the exhaust air chamber 14 carries a model 4, 4 'on the top and bottom on a fashion plate 3,3'. The mold frame or molding box 1 and Füf lrahmeπ 2 can for the upper model 4 and the lower model 4 ' be identical. The end plate 5, 5 'of both mold spaces is designed in this embodiment in such a way that it is guided on the inner walls of the filling frame 2, that is to say it can dip into the mold space. For this purpose, it is provided with a lifting drive, not shown. If necessary, only one end plate 5 or 5 'needs to be provided with such a drive. In this case, the model plates 3, 3 ', the mold frames 1, 1' and the filling frames 2, 2 'can be moved together in relation to the other end plate in the longitudinal axis.

In turn, two Laval nozzles 20 are arranged in the upper end plate 5 and two Laval nozzles 20 'in the lower end plate 5' in accordance with the design according to FIG. The upper Laval nozzles 20 each have a verse flow device 11, the lower Laval nozzles 20 'each have a closure device 11'. These are housed in the prechamber 8 or 8 '. Each prechamber is in turn connected to at least one compressed air reservoir 10, 10 '.

While the upper end plate 5 is primarily used for leveling and / or after compacting the molding sand, the lower end plate 5 'fulfills another task. By moving into the molding space, the molding sand 25 lying on it is raised until it encases or covers the contours of the model 4 'and the free surface of the model plate 3'. Only then does the expansion of the compressed air contained in the store 10 'take place after the closure device has been opened.

In order to enable the compressed air to be released as effectively as possible, the lower Laval nozzles 20 'are further connected via lateral bores 26 to a compressed air connection 27, via which compressed air for fluidizing the molding sand, especially within the Laval nozzles 20', is supplied becomes. As a result, the molding sand is kept in a state of suspension and at the same time is prevented from getting into the closure area of the valve when the closure devices 11 'are opened.

The molding machine shown in FIGS. 5 and 6 conventionally has a work table 36 which can be raised and lowered by means of a lifting piston 35. A model plate carrier 32 with the model 33 sits on the work table 36. In the exemplary embodiment shown, the model plate carrier 32 is designed as a hollow box and can be connected to a vacuum. T he model 33-carrying plate of the model plate carrier 32 is further provided with openings 41 through which air can be sucked out of the molding space.

A mold box 31 sits on the model plate carrier 32 and there is a filling attachment 34, which is also provided with a vacuum connection 42. D the molding space is finally closed at the top by a closure plate 38, 31 seals 40 being inserted between the latter and the Fulia attachment and between the latter and the molding box.

A spray device 45 for spraying liquids onto the molding material surface 46 is arranged on the closure plate 38. Also located on the closure plate 38 is a free jet nozzle 44 which opens into the mold space and is connected via a valve 43 to a compressed air source.

The closure plate 38 with spray device 45 and free jet nozzle 44 sits together with a filling vessel 37 containing the molding material on a carriage which can be moved over the molding space, so that either the filling vessel or the closure plate 38 is placed on the filling attachment 34. The device operates as follows:

First, the filling vessel 37 is located on the filling attachment 34. The metered amount of molding material contained therein is dispensed by opening a flap or blind closure on the bottom of the filling vessel 37 into the molding space delimited by the model plate holder 32, the molding box 31 and the filling attachment 34. Then the carriage is moved so that the closure plate 38 with spray device 45 and nozzle 44 passes over the filling set 34. Then the reciprocating piston 35 is actuated so that the entire mold space is raised and the closure plate 38 is pressed against fixed stops 39. In this position, the molding space is sealed off, which is then evacuated via the connections 42 in the filling set 34 and in the model plate carrier 32. In this way, the pore air is sucked out of the molding material filling. When the desired negative pressure of 0.4 to 0.2 bar is reached, liquid is sprayed onto the surface of the molding material by means of the spray device 44 and the valve 43 is immediately opened so that the compressed air impacts the molding surface 46 in the form of a free jet and the kinetic energy of the beam is converted into pressing force.

In the embodiment according to FIG. 6, the same system parts are designated with the same reference numerals as in the embodiment according to FIG. 5. In this respect, a repeated description is unnecessary. 5, the free jet nozzle 44 has a double jacket, its inner wall having openings, for example. a perforation is provided, while the outer wall has a vacuum connection 49. The double jacket can be connected to the vacuum source provided for evacuating the molding space via this connection. By applying negative pressure, the opening angle of the free Jet nozzle 44 can be increased above the limit of 14 ° because the vortices that are formed are suctioned off.

In a further deviation from the embodiment according to FIG. 5, on the filling vessel 37 and the closure plate 38 with the nozzle 44 and the carriage, which is not shown in FIG. 6, there is a press head 47 with a press plate 48 for recompressing the molding material. The mode of operation corresponds to that already described for FIG. 5. After compression by means of the compressed air jet, the work table 36 is lowered, the closure plate 38 is moved to the right with the nozzle 44 and at the same time the press head 47 is retracted until it is above the lowered filling attachment 34. Then the work table 35 is raised again, so that the press plate 48 comes into effect on the free molding surface 46. After the repressing, the molding is carried out in the usual way.

Claims

PATENT CLAIMS

1. A method for the pneumatic compression of foundry molding material which is enclosed in a closed mold space, the boundary of which is formed by a model encased by the molding sand, characterized in that the molding space filled with molding sand is filled with air at a pressure degree of greater than 100 bar / s is applied.

2. The method, in particular according to claim 1, characterized in that the pressure gradient is up to 1000 bar / s.

3. The method according to claim 1 or 2, characterized in that the pressure difference before and after filling the mold space between

0.8 and 8 bar.

4. The method according to claim 1 or 2, characterized in that the molding space filled with molding sand is evacuated to about 0.2 bar and then suddenly pressurized with compressed air.

5. The method according to any one of claims 1 to 3, characterized in that the molding space filled with molding sand, which is under normal pressure, is suddenly connected to a compressed air reservoir.

6. The method according to any one of claims 1 to 6, characterized in that the flow of the air flowing into the mold space is directed at any angle, preferably perpendicular to the molding sand surface.

7. A process for compressing foundry molding material in an evacuable molding space, in which the filled molding material is placed under negative pressure, characterized in that compressed air of up to 15 bar is brought into effect as a free jet on the free molding material surface.

8. The method according to claim 7, characterized in that the molding space is first filled with the molding material, then evacuated to 0.4 to 0, 2 bar and then the compressed air free jet is brought into effect.

9. The method according to claim 7, characterized in that the mold space is evacuated to 0.4 to 02, bar, then filled with the molding material and the compressed air jet is brought into effect on the free surface of the molding material.

10. The method according to any one of claims 7 to 9, characterized in that the compressed air free jet has supersonic speed.

11. The method according to any one of claims 7 to 10, characterized in that the free surface of the molding material is covered with a substance which increases the flow resistance of the near-surface layer before the application of the compressed air free jet.

12. The method according to any one of claims 7 to 11, characterized in that the molding material is mechanically pressed.

13. The apparatus for performing the method according to one of claims 1 to 6, with a molding space receiving the molding sand, which is formed by a model, a mold frame surrounding it and a molding space closure on the side opposite the model, characterized in that Molding space

(1, 2, 3, 5) is provided with at least one nozzle opening (6) opening outside the surface (19) of the molding sand and a closure device (11) assigned to it, which allows a pressure build-up of more than 100 bar / s in the molding space when opened .

14. The apparatus according to claim 13, characterized in that the nozzle opening (6) is arranged on the mold space termination (5).

15. The apparatus according to claim 13 or 14, characterized in that the molding space (1, 2, 3, 5) in the area free of molding sand (19) via the nozzle opening (6) with a pressure accumulator (10) is connected.

16. Device according to one of claims 13 to 15, characterized in that the axis of each nozzle opening (6) is arranged in any, preferably perpendicular direction to the molding sand surface (19).

17. Device according to one of claims 13 to 16, characterized in that each nozzle opening (6) is designed as a Laval nozzle (20).

18. The apparatus according to claim 17, characterized in that each Laval nozzle (20) is arranged and designed such that the free rays generated by these impinge approximately on the entire free molding sand surface (19).

19. Device according to one of claims 13 to 18, characterized in that the molding space (1, 2, 3, 5) in the region of the model (4) is provided with outflow openings (15) for the air.

20. The apparatus according to claim 19, characterized in that outflow openings (18) are also provided in the base of particularly deep contours of the model (4).

21. Device according to one of claims 13 to 20, characterized in that the molding space (1, 2, 3, 5) is optionally provided via the outflow openings (15, 18) with a vacuum connection (16).

22. The device according to any one of claims 13 to 21, characterized in that the mold space termination (5) is designed as the plate having the nozzle opening (6).

23. The apparatus according to claim 22, characterized in that the nozzle opening (6) is designed as a flat nozzle (7) of large cross section and the closure device (11) is designed as a large-area poppet valve (12) interacting with the plate.

24. Device according to one of claims 17, 18 and 22, characterized in that in the plate (5) at least one Laval nozzle (20) is used and the closure device (11) is designed as a poppet valve (12) which with the inflow opening (21st ) of the Laval nozzle (20) interacts.

25. The device according to claim 24, characterized in that two or more Laval nozzles (20) on the plate (5) are arranged at the same height and the closure device (11) from a single, with the inflow openings (21) of all Laval nozzles (20) cooperating poppet valve (12) is formed.

26. Device according to one of claims 13 to 25, characterized in that a prechamber (8) is arranged between the molding space (1, 2, 3, 5) and the compressed air reservoir (10), in which at least the moving parts of the closure device ( 11) are housed.

27. The device according to one of claims 13 to 16 and 19 to 21, characterized in that a prechamber (8) is arranged between the molding space (1, 2, 3, 5) and the compressed air reservoir (10) and the nozzle opening (6) with the verses! ußeinrichtung (11) is arranged on a lateral boundary wall (24) of the prechamber (8).

28. Device according to one of claims 13 to 27, characterized in that the prechamber (8) is pivotable or displaceable about a vertical axis lying outside the molding space (1, 2, 3, 5).

29. The device according to claim 27, characterized in that the prechamber (8) has a molding sand fill opening, which can be closed in a pressure-tight manner.

30. Device according to one of claims 13 to 29, characterized in that the plate (5, 5 ') forming the end of the molding space (1, 2, 3, 5) on the inner walls of the molding space (1, 2) is pressure-tight and is provided with a linear actuator.

31. The device according to any one of claims 13 to 30 with a double-sided model and a lower and upper mold space assigned to a model side, characterized in that at least the lower mold space (1 ', 2', 3 ', 5') assigned

Nozzle openings (20 ') are provided with a compressed air connection (27) for fluidizing the molding sand (25).

32. Apparatus for carrying out the method according to one of claims 7 to 12 with a model plate carrier, an attached molding box, an overlying filling attachment and a closure plate, which together form the molding space, and with a filling vessel containing the molding material, characterized by one or more in the mold space (31, 32, 34) opening, connected to a compressed air source free jet nozzles (44).

33. Apparatus according to claim 32, characterized in that the wall of the free jet nozzle (44) has openings which can be connected to vacuum (49).

34. Apparatus according to claim 33, characterized in that the free jet nozzle (44) has a double wall and the space formed by the walls is provided with a vacuum connection (49).

35. Device according to one of claims 32 to 34 for performing the method according to claim 11, characterized in that in the upper region of the molding space (31, 32, 34) a device (45) for spraying liquid onto the free molding material surface ( 46) is arranged.

36. Device according to one of claims 32 to 35, characterized in that the free jet nozzle (44) and the spray device (45) are arranged on the closure plate (38).

37. Device according to one of claims 32 to 36, characterized in that the closure plate (38) with a free jet nozzle (44) and spray device (45) and the molding material filling vessel (34) on a trolley or carousel over which the filling attachment (34) passes are arranged.

38. Apparatus according to claim 37 for performing the method according to claim 12, characterized in that a press plate (48) is further arranged on the car or carousel.