EP0139119B1 - Method of and installation for compacting granular moulding materials, for example foundry mould sand - Google Patents

Method of and installation for compacting granular moulding materials, for example foundry mould sand Download PDF

Info

Publication number
EP0139119B1
EP0139119B1 EP84108988A EP84108988A EP0139119B1 EP 0139119 B1 EP0139119 B1 EP 0139119B1 EP 84108988 A EP84108988 A EP 84108988A EP 84108988 A EP84108988 A EP 84108988A EP 0139119 B1 EP0139119 B1 EP 0139119B1
Authority
EP
European Patent Office
Prior art keywords
pressure
piston
bottom plate
valve
openings
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP84108988A
Other languages
German (de)
French (fr)
Other versions
EP0139119A1 (en
EP0139119B2 (en
Inventor
Josef Mertes
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Family has litigation
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=6205541&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=EP0139119(B1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by Individual filed Critical Individual
Priority to AT84108988T priority Critical patent/ATE37305T1/en
Publication of EP0139119A1 publication Critical patent/EP0139119A1/en
Publication of EP0139119B1 publication Critical patent/EP0139119B1/en
Application granted granted Critical
Publication of EP0139119B2 publication Critical patent/EP0139119B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C15/00—Moulding machines characterised by the compacting mechanism; Accessories therefor
    • B22C15/28—Compacting by different means acting simultaneously or successively, e.g. preliminary blowing and finally pressing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C15/00—Moulding machines characterised by the compacting mechanism; Accessories therefor

Definitions

  • the invention relates to a method according to the preamble of claim 1 and an apparatus for carrying out the method according to the preamble of claim 6.
  • DE-A-3105 350 e.g. Measures are described which are intended to deliberately separate the partial streams of the Laval nozzles arranged in a coarse-meshed grid.
  • the partial flows which are bundled according to the Laval characteristics, hit the loose molding material at certain points and tear deep craters there, which can reveal high-lying model parts. In addition to the churned, crater-like surface of the back of the mold, this also leads to uneven compaction.
  • EP-A-36 434 describes an airflow pressing method in which compressed air is blown into the molding material and sucked off again on the model plate.
  • the compressed air is blown in above the surface of the molding material via channels with "sand-fitter nozzles", which are known to have only the smallest cross-sections.
  • the sand filter nozzles cause the compressed air flowing from a central outlet to accumulate, in order to then allow it to flow out of the sand filter nozzles in a uniform manner.
  • the horizontal and vertical as well as the opposite arrangement of the sand filter nozzles result in considerable energy losses. Since the flow-through process can only take place relatively slowly, it is not possible to use the potential compressed air energy for sudden compression.
  • model plate has to be equipped with sand filter nozzles to extract the compressed air and that a vacuum source is also required.
  • the molding material mass is accelerated and compressed by subsequent braking on the model plate.
  • the ideal characteristic for casting technology has the disadvantage that the back of the mold does not meet practical requirements, particularly with regard to pouring pots and pouring funnels.
  • An integrated device is therefore required which eliminates this disadvantage without, however, significantly influencing the advantageous shape hardness curve. It would be advantageous if this same device also slightly presses the loose molding material surface before the pressure is applied. This on the one hand reduces the air pore volume in the loose surface of the molding material and on the other hand reduces the penetration of the compressed air into the molding material.
  • the device described above is not available in the previously known devices with the compressed air method.
  • the object of the present invention is to avoid the disadvantages described and to propose a method and a device with which a frontal, uniform and perpendicularly acting pressure wave is generated which uniformly compresses the molding material at high speed and which has an integrated device for pretreatment and aftertreatment the back of the mold.
  • the valve lifters and the main piston together form a differential piston system.
  • the pressure medium of the pressure gas chamber is constantly present as potential energy on the main piston. An external energy source is not required.
  • the release of the entire outlet cross section only requires the very small stroke of d / 4 of a small circular outlet opening. Together, these criteria open the entire outlet cross section in just a few milliseconds.
  • the main piston does not require any seals because it is driven by the medium in the compressed gas chamber and because the opened state only lasts a fraction of a second.
  • the frame has generously sized openings for throttling-free flow of the pressure medium.
  • the cross-section between the valve lifters is generously dimensioned.
  • the piston cavity and the lower cylinder space are integrated components of the compressed gas chamber. The latter results in an almost instantaneous reaction of the main piston.
  • the valve lifters are made of an elastic material such. B. rubber. Due to the spring action, they support the lifting of the main piston during the opening process.
  • the spring travel of the elastic valve lifters also has the effect that the inertia of the piston and the frame is first overcome before the valve lifters lift off the valve seat at a definable initial speed. Since the acceleration time from the speed value zero to the starting or lifting speed of the valve lifters does not affect the lifting time for the stroke d / 4 and the starting speed increases progressively due to the increasing acceleration (page 8 - line 25), this criterion also has an effect Open the entire outlet cross section in just a few milliseconds.
  • the method according to the invention can be used in particular in the foundry for the compression of molds and cores, and in the construction industry for the compression of building materials. In addition, the method according to the invention can also be used for the compression of any other molding materials.
  • the 1 shows a model plate 5 with model 5a together with a molding box 7 and a filling frame 8. Above it is the base plate 54, which has a large number of small, circular openings 53 with cross sections similar to Laval nozzles.
  • the base plate 54 is part of the compressed air chamber 17 arranged above it.
  • the compressed air chamber 17 is connected to the two symmetrically arranged wind boilers 43 via the generously dimensioned lines 42 in order to increase the output volume.
  • the pressure in the compressed air chamber is 5 bar.
  • the air-permeable frame 45 which carries the elastic valve tappets 52, 65, is located in the compressed air chamber 17.
  • the generously dimensioned bores 14, 57, 67 in the frame 45 enable the compressed air to flow without throttling.
  • the elastic valve lifters 52, 65 close the openings 53 in the base plate 54.
  • the frame 45 is fastened to the piston 41.
  • the piston 41 which causes the opening and closing of the base plate openings 53, slides in a cylinder, the lower space 21 of which is an integral part of the compressed air chamber 17.
  • the piston cavity 20 is an integral part of the compressed air chamber 17.
  • a vertically movable flange 11 is suspended from four pneumatic cylinders 44 on the outer edge of the housing 15.
  • the pneumatic cylinders are under constant pressure on the piston side and thus act as a pneumatic spring. In the starting position, the pistons hit the stops 16 pressed.
  • the flange 11 has the task of producing a pressure-tight connection between the housing 15 and the filling frame 8 with its seals 9 and 13.
  • the seal 9 is a static seal, while the seal 13 can be activated with compressed air. In the non-activated state, the seal 13 withdraws behind the inner surface of the flange and the housing 15 can be moved through the flange 11 without contact with the play 46. In the activated state, the seal 13 is pressed against the outer wall of the housing 15.
  • Fig. 1 left half section shows the device in the starting position.
  • the model plate 5 with model 5a, molding box 7 and filling frame 8 is moved over the roller conveyor 4 under the base plate 54.
  • the molding material 6 is loosely and evenly piled up to the surface 50.
  • the model plate 5 is lifted off the roller conveyor 4 and with the further upward movement the filling frame 8 is pressed under the flange 11, which is then also moved upwards against the pneumatic spring pressure 44.
  • the upward movement is carried out until the base plate 54 has slightly pressed the loose molding material surface 50 to reduce its air pore volume.
  • the loose molding material surface 50 is then brought into a defined distance 49 from the base plate 54 by a downward movement (firing position). However, it is also possible to dispense with gently pressing the surface of the molding material.
  • the upward movement is then carried out directly up to the defined distance 49 (shot position).
  • Fig. 1 right half section shows the device in the firing position, with "firing" means the sudden escape of the compressed air.
  • the seal 13 is first activated.
  • the pneumatic spring pressure 44 presses the seal 9.
  • this pneumatic spring pressure counteracts the force that is created by the pressure acting on the gap 48.
  • the system is then sealed pressure-tight and the compression of the pressure waves can be released.
  • the housing of the compressed air chamber 17 is connected via the head frame 22, the columns 55, the base frame 1 and the cylinder 2 to the lifting table 3 to form a force-locking system.
  • the result of this is that the air jets emerging close to one another mix and form a pressure wave as the distance 49 progresses.
  • the pressure wave hits the loose molding material surface 50 at high speed.
  • the molding material 6 is accelerated and compressed on the model plate 5 by subsequent braking.
  • the compressed air relaxes in the closed system with an adiabatic course to a defined final pressure.
  • the greatest compression occurs in the area of the model plate because this, as a rigid and unyielding mass, causes the greatest deceleration of the molding material particles and because the full mass of the molding material is still effective here.
  • the compression of the molding material decreases slightly in the course of the surface 51 because the molding material mass and thus the mass energy decrease and because the upper layers of the molding material are no longer braked directly on the rigid model plate but in the intermediate layers of the molding material.
  • the valve 12 is opened after the bottom plate openings 53 have been closed. The residual pressure above the molding material surface 51 is again increased to the system pressure 6 bar and this is kept as a static pressure above the molding material surface 51 for a short time.
  • the space between base plate 54 and molding surface 51 is depressurized again via valve 10.
  • Another possibility of post-compaction is that the molding material surface 51 is pressed against the base plate 54 by means of a lifting table 3. This is done by previously releasing the residual pressure above the molding material surface 51 through the valve 10 and releasing the seal 13.
  • the effective pressing surface 59 between the openings 53 is approximately 50% of the total molding surface 51.
  • the lifting table is lowered again, as a result of which the model plate 5 with model 5a, molding box 7, filling frame 8 and the compacted mold is again placed on the roller conveyor 4.
  • the model plate 5 with the units lying on it is moved out.
  • the other half of the model is moved under the base plate 54 from the opposite side and a new compression cycle begins when the lifting table 3 is raised.
  • the sum of the cross-sectional areas 47, 60 and the cross-sectional area of the piston 41 together form a differential piston system.
  • the cross-sectional area of the piston 41 is greater than the sum of all cross-sectional areas 47, 60.
  • the same pressure values of the compressed air chamber 17 are present in the cylinder chambers 21 and 24 and above the valve tappets 52. This results in a resultant force which the valve lifters 52, 65 press onto their seat. This force corresponds to the product of the sum of all cross-sectional areas 47, 60 and the pressure of the compressed air chamber 17. If the pressure in the cylinder space 24 is released to atmospheric pressure, an upward force results because the cross-sectional area of the piston 41 is larger than that Sum of all cross-sectional areas 47, 60.
  • this force corresponds to the product of the differential cross-sectional area and the pressure of the compressed air chamber.
  • this force increases because the entire cross-sectional area of the piston 41 becomes effective as the valve tappets become free.
  • the pressure decreases from 5 bar to approx. 3.5 bar in accordance with the volume ratios and the adiabatic curve.
  • the area ratios are designed in such a way that a force is available at the start of the stroke of the valve lifter, which ensures that the dead weight and the friction are overcome as well as the required acceleration. The further increase in force can thus cause an additional acceleration, which in turn is important for the rapid opening.
  • the piston sliding surfaces 18 and 23 are provided with guide bands which have a very low coefficient of friction and are highly wear-resistant. They also prevent metallic contact between the piston and cylinder material. Seals are not required on the piston sliding surfaces 18 and 23 because the piston 41 is acted upon on both sides by the same system pressure when the openings 53 are closed.
  • the open state in which the cylinder chamber 24 is relieved to atmospheric pressure via the generously dimensioned quick-exhaust valve 36, lasts for a maximum of only 1 second. The minor leaks that occur are accepted because they do not affect the function.
  • a spring damping 39 is installed in the cylinder space 24, which brings the piston 41 to a standstill over a defined braking distance.
  • a correspondingly resilient plastic disk 40 is applied to the piston surface, which prevents the piston from striking metal onto the surface of the spring damping 39.
  • the guides 56 which can also be designed as rollers, prevent the frame 45 from rotating. They are set with a slight play so that the lifting movement of the frame is not hindered.
  • the valve lifters 52, 65 consist of an elastic material 64 (for example rubber) which is vulcanized onto a steel core 63.
  • the steel core 63 and the screw head 62 support the elastic material against the outward system pressure.
  • the surfaces 68 and 61, 70 run exactly plane-parallel.
  • the length 69 of the valve lifters 52, 65 corresponds to this plane-parallel distance within a defined tolerance range. Tolerance differences are adjusted by the elasticity of the valve lifters.
  • the exact length 69 is manufactured within the specified tolerance range.
  • the rubber mass 64a represents a spring compressed by the locking force, which with its pretension assists the lifting of the piston 41 and the frame 45 during the opening process and which also causes the valve lifters 52, 65 to be lifted off the valve seat at a defined initial speed greater than zero.
  • the lower housing part 15 is released on the quick-release fastener 19 and lowered with the lifting table 3 and by means of a simple one .Pallet moved sideways over the roller conveyor 4.
  • the valve lifters 52, 65 are then freely accessible from below.
  • the compressed air is fed in from the network with the nominal pressure 6 bar via the shut-off valve 27 and the filter 26. From there, the working air is supplied to the two wind boilers 43 via the valve 30 and the pressure regulator 31. The control air is removed behind the compressed air lubricator 29 and fed to the cylinder chamber 24 via the valves 32 and 34.
  • the quick breather valves 36 are used for quick venting of the cylinder space 24.
  • the valve 12 is used for post-compression of the molding surface 51 and the valve 10 is used for relieving the space above the molding surface 51.
  • Valve 37 is the main safety valve. With the pressure control valve 31, the working pressure is kept at 5 bar.
  • valve 34 In the starting position, valve 34 is open when de-energized (safety circuit), valve 32 is closed when de-energized, and valve 30 is opened when current is applied.
  • the valves 10, 12 and 28 are closed when de-energized.
  • the pressure of the compressed air chamber 17 and the wind chamber 43 is present in the cylinder chamber 24 via the check valve 33, the valve 34 and the quick-vent valve 36.
  • the piston 41 is pressed down and the valve tappets 52, 65 thus close the openings 53.
  • the valve 28 When the device is in the firing position, the valve 28 is first switched and thus the seal 13 is activated. Then valve 34 is turned on and valve 30 is turned off. The valve 30 interrupts the further supply of the working air.
  • the valve 34 interrupts the supply of the control air and at the same time relieves the pressure on the quick breather valves 36.
  • the cylinder space 24 is relieved in a very short time via a large and throttle-free cross section of the quick breather valves 36 and the downstream silencers 35.
  • the piston 41 lifts the valve lifters 52, 65 and the base plate openings 53 are released in a few milliseconds.
  • the compressed air emerges from the compressed air chamber and - as already described - compresses the molding material.
  • the pressure drops in accordance with the change in volume and taking into account the adiabatic curve from 5 bar to approx. 3.5 bar. After the pressure wave compression, the valves 32 and 34 are opened.
  • the piston 41 is moved downwards with the network pressure of 6 bar and the valve tappets 52, 65 close the openings 53 again.
  • the valve 12 is opened for a short time for subsequent compression.
  • the valve 32 is closed and the valve 30 is opened, as a result of which the compressed air chamber 17 and the air boiler 43 are brought back to the initial pressure of 5 bar and the cylinder chamber 24 is switched again from the 6 bar system to the 5 bar system of the compressed air chamber 17 .
  • the valve 10 is opened briefly. Then the seal 13 is relieved via the valve 28.
  • the compression process is finished and the lifting table 3 can lower the model plate 5 back onto the roller conveyor 4.
  • FIG. 7 shows an embodiment variant which can be used with particularly large surfaces of molding material.
  • the outlet openings 71 are dimensioned accordingly large and each valve tappet 73 has its own drive piston 75.
  • Valve tappet 73 and drive piston 75 together form a differential piston system with the same mode of operation as described on page 8.
  • a ball joint suspension 74 with a small, all-round angular stop ensures that the large-area valve disk 73 rests plane-parallel on the sealing surface 72.
  • the conical hoods 76 reduce the flow resistance.

Abstract

1. A process for compressing granular moulding material such as foundry moulding sand by means of a pressure wave of gaseous medium such as compressed air acting at high speed on the surface of the loose moulding material, with the compression medium emerging uniformly form Laval-type nozzles that are arraged close together in a raster system in a bottom plate (54) over the entire surface of the moulding material (50), characterized in that the single air jets burst open at the nozzle outlet so that the air jets emerging close to each other intermingle and impinge vertically as well as uniformly at all points as a pressure wave on the surface (50) of the loose moulding material.

Description

Die Erfindung betrifft ein Verfahren nach dem Oberbegriff des Anspruches 1 sowie eine Vorrichtung zur Durchführung des Verfahrens nach dem Oberbegriff des Anspruches 6.The invention relates to a method according to the preamble of claim 1 and an apparatus for carrying out the method according to the preamble of claim 6.

Neben den rein mechanischen Verfahren zur Formstoffverdichtung durch Rütteln und Pressen sowie durch Einschießen des Formstoffes mit anschließende Nachpressen, sind Verfahren bekannt, bei denen der Formstoff durch die Druckwirkung eines explodierenden Gases oder durch die unmittelbare Einwirkung von Druckluft verdichtet wird. So sind z. B. entsprechende Vorrichtungen in den Druckschriften DE-3 025 993 und DE-2 949 340 (Explosionsverfahren) sowie in den Druckschriften DE-1 097 622, EP-A-36 434 und DE-3 105350 (Druckluftverfahren) beschrieben.In addition to the purely mechanical methods for compression molding by shaking and pressing and by shooting in the molding material with subsequent repressing, methods are known in which the molding material is compressed by the pressure effect of an exploding gas or by the direct action of compressed air. So z. B. corresponding devices in the publications DE-3 025 993 and DE-2 949 340 (explosion process) and in the publications DE-1 097 622, EP-A-36 434 and DE-3 105350 (compressed air process).

Bei dem Explosionsverfahren ist es nachteilig, daß ein explosives Medium angewendet werden muß. Dieses macht erhebliche Maßnahmen der Sicherheit und des Umweltschutz es erforderlich. Außerdem wird die Vorrichtung und der Formstoff erheblichen Temperaturbelastungen ausgesetzt, was u.a. zu einer starken Austrocknung der Formstoffoberfläche führt. Ferner ist davon auszugehen, daß sich die Druckwelle durch die Explosion sternförmig ausbreitet und somit nicht an allen Stellen gleichmäßig und senkrecht als frontale Druckwelle auf die lose Formstoffoberfläche auftrifft.With the explosion process, it is disadvantageous that an explosive medium must be used. This necessitates significant safety and environmental measures. In addition, the device and the molding material are exposed to considerable temperature loads, which among other things. leads to a strong drying of the molding material surface. Furthermore, it can be assumed that the pressure wave spreads in a star shape as a result of the explosion and therefore does not strike the loose molding material surface uniformly and vertically at all points as a frontal pressure wave.

Die bekannten Vorrichtungen mit den Druckluftverfahren haben den Nachteil, daß die Druckluft punktuell und nicht gleichmäßig frontal auf die lose Formstoffoberfläche auftrifft. In DE-A-3105 350 werden z.B. Maßnahmen beschrieben, die gezielt eine Trennung der Teilströme der in einem grobmaschigen Raster angeordneten Lavaldüsen bewirken sollen. Die Teilströme, die gemäß der Lavalcharakteristik gebündelt verlaufen, treffen somit punktuell auf den losen Formstoff auf und reißen dort tiefe Krater, die hochliegende Modellpartien aufdecken können. Neben der aufgewühlten kraterähnlichen Oberfläche der Formrückenseite führt dies auch zu einer ungleichmäßigen Verdichtung. Weitere Nachteile sind, daß die kegelförmigen Ventilteller einen großen Ventilhub erfordern und daß ein externer Antrieb mit fremder Energiequelle das Ventil oder die Ventile öffnet, was insgesamt gesehen die für das Verfahren bedeutsame Schnelligkeit des Systems negativ beeinflußt. Darüberhinaus sind Vorrichtungen bekannt, bei denen die Druckluft nach einem zentralen Auslaß über Schikanen auf die lose Formstoffoberfläche geleitet wird, was zu erheblichen Energieverlusten führt.The known devices with the compressed air process have the disadvantage that the compressed air hits the loose molding material surface selectively and not evenly frontally. DE-A-3105 350 e.g. Measures are described which are intended to deliberately separate the partial streams of the Laval nozzles arranged in a coarse-meshed grid. The partial flows, which are bundled according to the Laval characteristics, hit the loose molding material at certain points and tear deep craters there, which can reveal high-lying model parts. In addition to the churned, crater-like surface of the back of the mold, this also leads to uneven compaction. Further disadvantages are that the conical valve plates require a large valve stroke and that an external drive with an external energy source opens the valve or the valves, which overall has a negative effect on the speed of the system which is important for the method. In addition, devices are known in which the compressed air is guided to the loose surface of the molding material via baffles after a central outlet, which leads to considerable energy losses.

In EP-A-36 434 wird ein Luftstrom-Preßverfahren beschrieben, bei dem Druckluft in den Formstoff eingeblasen und an der Modellplatte wieder abgesaugt wird. Das Einblasen der Druckluft erfolgt dabei oberhalb der Formstoffoberfläche über Kanäle mit "Sandfitterdüsen", die bekanntlich nur kleinste Querschnitte haben. Die Sandfilterdüsen bewirken dabei ein Anstauen der von einem Zentralauslaß anströmenden Druckluft, um sie dann vergleichmäßigt aus den Sandfilterdüsen ausströmen zu lassen. Durch die horizontale und vertikale sowie auch durch die entgegengesetzte Anordnung der Sandfilterdüsen entstehen erhebliche Energieverluste. Da der Durchströmvorgang nur relativ langsam ablaufen kann, ist die Nutzung der potentiellen Druckluftenergie für eine schlagartige Verdichtung nicht möglich. Mit diesem Verfahren kann daher nur eine Vorverdichtung aber keine Endverdichtung erreicht werden. Ein mechanisches Nachpressen ist daher zwingend erforderlich. Nachteilig ist auch, daß die Modellplatte zum Absaugen der Druckluft mit Sandfilterdüsen bestückt werden muß und daß außerdem eine Unterdruckquelle erforderlich ist.EP-A-36 434 describes an airflow pressing method in which compressed air is blown into the molding material and sucked off again on the model plate. The compressed air is blown in above the surface of the molding material via channels with "sand-fitter nozzles", which are known to have only the smallest cross-sections. The sand filter nozzles cause the compressed air flowing from a central outlet to accumulate, in order to then allow it to flow out of the sand filter nozzles in a uniform manner. The horizontal and vertical as well as the opposite arrangement of the sand filter nozzles result in considerable energy losses. Since the flow-through process can only take place relatively slowly, it is not possible to use the potential compressed air energy for sudden compression. With this method, therefore, only a pre-compression but no final compression can be achieved. Mechanical re-pressing is therefore imperative. It is also disadvantageous that the model plate has to be equipped with sand filter nozzles to extract the compressed air and that a vacuum source is also required.

Beim Auftreffen der Druckluft auf die lose Formstoffoberfläche, wird die Formstoffmasse beschleunigt und durch nachfolgendes Abbremsen auf der Modellplatte verdichtet. Es entsteht hierbei der charakteristische Formhärteverlauf mit hohen Werten an der Modellseite und niedrigen Werten an der Formrückseite, die von der Druckluft direkt beaufschlagt wurde. Die für die Gießtechnik ideale Charakteristik hat aber den Nachteil, daß die Formrückseite nicht den Anforderungen der Praxis entspricht, insbesondere im Hinblick auf Gießtümpel und Eingußtrichter. Es bedarf daher einer integrierten Einrichtung die diesen Nachteil beseitigt ohne jedoch den vorteilhaften Formhärteverlauf wesentlich zu beeinflussen. Vorteilhaft wäre, wenn diese gleiche Einrichtung auch die lose Formstoffoberfläche vor der Druckeinwirkung leicht andrückt. Dadurch wird einerseits das Luftporenvolumen in der losen Oberfläche des Formstoffes reduziert und andererseits des Eindringen der Druckluft in den Formstoff vermindert. Die zuvor beschriebene Einrichtung ist bei den bisher bekannten Vorrichtungen mit dem Druckluftverfahren nicht vorhanden.When the compressed air hits the loose surface of the molding material, the molding material mass is accelerated and compressed by subsequent braking on the model plate. This creates the characteristic mold hardness curve with high values on the model side and low values on the back of the mold, which was directly affected by the compressed air. However, the ideal characteristic for casting technology has the disadvantage that the back of the mold does not meet practical requirements, particularly with regard to pouring pots and pouring funnels. An integrated device is therefore required which eliminates this disadvantage without, however, significantly influencing the advantageous shape hardness curve. It would be advantageous if this same device also slightly presses the loose molding material surface before the pressure is applied. This on the one hand reduces the air pore volume in the loose surface of the molding material and on the other hand reduces the penetration of the compressed air into the molding material. The device described above is not available in the previously known devices with the compressed air method.

Aufgabe der vorliegenden Erfindung ist es, die beschriebenen Nachteile zu vermeiden und ein Verfahren und eine Vorrichtung vorzuschlagen, womit eine frontale, gleichmäßige und senkrecht wirkende Druckwelle erzeugt wird, die mit hoher Geschwindigkeit den Formstoff gleichmäßig verdichtet und die eine integrierte Einrichtung zur Vor- und Nachbehandlung der Formrückseite aufweist.The object of the present invention is to avoid the disadvantages described and to propose a method and a device with which a frontal, uniform and perpendicularly acting pressure wave is generated which uniformly compresses the molding material at high speed and which has an integrated device for pretreatment and aftertreatment the back of the mold.

Diese Aufgabe wird erfindungsgemäß gelöst durch die kennzeichnenden Merkmale der Ansprüche 1 und 6. Weitere Merkmale und besondere Ausführungsformen sind in den sonstigen Ansprüchen angegeben.This object is achieved according to the invention by the characterizing features of claims 1 and 6. Further features and special embodiments are specified in the other claims.

Die Vorteile der vorliegenden Erfindung werden insbesondere durch folgende Merkmale gekennzeichnet:

  • - die Bodenplatte weist eine große Anzahl kleiner kreisförmiger Öffnungen mit lavaldüsenähnlichen Querschnitten auf, die so ausgebildet sind, daß der Luftstrahl am Ausgang der Düse leicht aufplatzt. Dies bewirkt im Zusammenhang mit einer definierten, minimalen Distanz zwischen Bodenplatte und der losen Formstoffoberfläche die Ausbildung einer frontalen Druckwelle, die senkrecht und gleichmäßig auf die lose Formstoffoberfläche auftrifft und somit zu einer gleichmäßigen Verdichtung führt.
  • - die Bodenplatte weist an der Unterseite zwischen den kreisförmigen Düsenausgangen eine noch ausreichende ca. prozentige Fläche zum Andrücken und Nachpressen des Formstoffes auf. Die Bodenplatte kann daher als integrierte Preßvorrichtung benutzt werden. Außerdem ist ein Nachverdichten auch durch Druckerhöhung des entspannten Gases möglich.
The advantages of the present invention are characterized in particular by the following features:
  • - The base plate has a large number of small circular openings with Laval nozzle-like cross-sections, so are designed so that the air jet bursts easily at the outlet of the nozzle. In connection with a defined, minimum distance between the base plate and the loose molding surface, this causes the formation of a frontal pressure wave, which strikes the loose molding surface vertically and evenly and thus leads to a uniform compaction.
  • - The base plate on the underside between the circular nozzle outlets still has a sufficient approx. percent area for pressing and pressing the molding material. The base plate can therefore be used as an integrated pressing device. In addition, post-compression is also possible by increasing the pressure of the expanded gas.

- Die Ventilstößel und der Hauptkolben bilden zusammen ein Differentialkolbensystem. Das Druckmedium der Druckgaskammer steht ständig als potentielle Energie am Hauptkolben an. Eine fremde Energiequelle ist nicht erforderlich. Die Freigabe des gesamten Auslaßquerschnittes erfordert nur den sehr geringen Hub von d/4 einer kleinen kreisförmigen Auslaßöffnung. Zusammen bewirken diese Kriterien ein Öffnen des gesamten Auslaßquerschnittes in nur wenigen Millisekunden.- The valve lifters and the main piston together form a differential piston system. The pressure medium of the pressure gas chamber is constantly present as potential energy on the main piston. An external energy source is not required. The release of the entire outlet cross section only requires the very small stroke of d / 4 of a small circular outlet opening. Together, these criteria open the entire outlet cross section in just a few milliseconds.

- Der Hauptkolben benötigt keine Dichtungen, weil er mit dem Medium der Druckgaskammer angetrieben wird und weil der geöffnete Zustand nur Bruchteile von Sekunden dauert. - Der Rahmen hat zum drosselfreien Nachströmen des Druckmediums die großzügig bemessenen Öffnungen. Außerdem ist auch der Querschnitt zwischen den Ventilstößeln großzügig bemessen. Der Kolbenhohlraum und der untere Zylinderraum sind integrierte Bestandteile der Druckgaskammer. Letzteres bewirkt ein annähernd verzögerungsfreies Reagieren des Hauptkolbens.- The main piston does not require any seals because it is driven by the medium in the compressed gas chamber and because the opened state only lasts a fraction of a second. - The frame has generously sized openings for throttling-free flow of the pressure medium. In addition, the cross-section between the valve lifters is generously dimensioned. The piston cavity and the lower cylinder space are integrated components of the compressed gas chamber. The latter results in an almost instantaneous reaction of the main piston.

- Die Ventilstößel bestehen aus einem elastischen Material z. B. Gummi. Durch die Federwirkung unterstützen sie beim Öffnungsvorgang das Anheben des Hauptkolbens. Der Federweg der elastischen Ventilstößel bewirkt außerdem, daß zunächst die Massenträgheit des Kolbens und des Rahmens überwunden wird, bevor die Ventilstößel mit einer definierbaren Anfangsgeschwindigkeit vom Ventilsitz abheben. Da die Beschleunigungszeit vom Geschwindigkeitswert Null bis zur Anfangs- bzw. Abhebegeschwindigkeit der Ventilstößel nicht in die Hubzeit für den Hub d/4 eingeht und sich die Anfangsgeschwindigkeit durch die weiter steigende Beschleunigung (Seite 8 -Zeile 25) progressiv erhöht, bewirkt auch dieses Kriterium ein Öffnen des gesamten Auslaßquerschnittes in nur wenigen Millisekunden.- The valve lifters are made of an elastic material such. B. rubber. Due to the spring action, they support the lifting of the main piston during the opening process. The spring travel of the elastic valve lifters also has the effect that the inertia of the piston and the frame is first overcome before the valve lifters lift off the valve seat at a definable initial speed. Since the acceleration time from the speed value zero to the starting or lifting speed of the valve lifters does not affect the lifting time for the stroke d / 4 and the starting speed increases progressively due to the increasing acceleration (page 8 - line 25), this criterion also has an effect Open the entire outlet cross section in just a few milliseconds.

Das erfindungsgemäße Verfahren kann insbesondere in der Gießerei zur Verdichtung von Formen und Kernen, sowie in der Bauindustrie zur Verdichtung von Baustoffen Anwendung finden. Außerdem kann das erfindungsgemäße Verfahren auch zur Verdichtung von irgendwelchen anderen Formstoffen verwendet werden.The method according to the invention can be used in particular in the foundry for the compression of molds and cores, and in the construction industry for the compression of building materials. In addition, the method according to the invention can also be used for the compression of any other molding materials.

Nachstehend wird nun die Erfindung anhand der in den Zeichnungen dargestellten Ausführungsbeispiele beschrieben. Hierbei zeigen:

  • Fig. 1 einen Längsschnitt durch die erfindungsgemäße Vorrichtung linker Halbschnitt: in Ausgangsstellung rechter Halbschnitt: in Arbeitsstellung
  • Fig. 2 einen Querschnitt durch die Ventilstößel gemäß-Linie A-A, Fig. 1
  • Fig. 3 einen Querschnitt durch den Rahmen gemäß Linie B-B, Fig. 1
  • Fig. 4 eine Unteransicht der Bodenplatte gemäß Linie C-C, Fig. 1
  • Fig. 5 einen Längsschnitt durch einen Ventilstößel gemäß Linie D-D, Fig. 3
  • Fig. 6 ein Anordnungsbeispiel der erfindungsgemäßen Vorrichtung
  • Fig. 7 einen Teilschnitt einer anderen Ventilstößelausführung
The invention will now be described with reference to the embodiments shown in the drawings. Here show:
  • 1 shows a longitudinal section through the device according to the invention, left half section: in the starting position, right half section: in the working position
  • 2 shows a cross section through the valve lifter according to line AA, FIG. 1
  • 3 shows a cross section through the frame according to line BB, FIG. 1
  • 4 shows a bottom view of the base plate according to line CC, FIG. 1
  • 5 shows a longitudinal section through a valve lifter according to line DD, FIG. 3
  • Fig. 6 shows an arrangement example of the device according to the invention
  • Fig. 7 is a partial section of another valve lifter design

Fig. 1 zeigt eine Modellplatte 5 mit Modell 5a zusammen mit einem Formkasten 7 und einem Füllrahmen 8. Darüber befindet sich die Bodenplatte 54, die eine große Anzahl kleiner, kreisförmiger Öffnungen 53 mit lavaldüsenähnlichen Querschnitten aufweist. Die Bodenplatte 54 ist Bestandteil der darüber angeordneten Druckluftkammer 17. Die Druckluftkammer 17 ist zur Vergrößerung des Ausgangsvolumens über die großzügig dimensionierten Leitungen 42 mit den zwei symetrisch angeordneten Windkesseln 43 verbunden. Der Druck in der Druckluftkammer beträgt 5 bar. In der Druckluftkammer 17 befindet sich der luftdurchlässige Rahmen 45, der die elastischen Ventilstößel 52,65 trägt. Die großzügig ausgelegten Bohrungen 14, 57, 67 im Rahmen 45 ermöglichen ein drosselfreies Durchströmen der Druckluft. Die elastischen Ventilstößel 52, 65 verschließen die Öffnungen 53 in der Bodenplatte 54. Der Rahmen 45 ist am Kolben 41 befestigt. Der Kolben 41, der das Öffnen und Schließen der Bodenplattenöffnungen 53 bewirkt, gleitet in einem Zylinder, dessen unterer Raum 21 integrierter Bestandteil der Druckluftkammer 17 ist. Ebenso ist der Kolbenhohlraum 20 integrierter Bestandteil der Druckluftkammer 17. Am Außenrand des Gehäuses 15 ist ein senkrecht beweglicher Flansch 11 an vier Pneumatikzylindern 44 aufgehängt. Die Pneumatikzylinder stehen kolbenseitig unter Dauerdruck und sie wirken somit als pneumatische Feder. In der Ausgangsstellung werden die Kolben gegen die Anschläge 16 gedrückt. Der Flansch 11 hat die Aufgabe, mit seinen Dichtungen 9 und 13 eine druckdichte Verbindung zwischen dem Gehäuse 15 und dem Füllrahmen 8 herzustellen. Die Dichtung 9 ist eine statische Dichtung, während die Dichtung 13 mit Druckluft aktivierbar ist. Im nicht aktivierten Zustand zieht sich die Dichtung 13 hinter die Flanschinnenfläche zurück und das Gehäuse 15 kann mit dem Spiel 46 berührungslos durch den Flansch 11 bewegt werden. Im aktivierten Zustand wird die Dichtung 13 gegen die Außenwand des Gehäuses 15 gepreßt.1 shows a model plate 5 with model 5a together with a molding box 7 and a filling frame 8. Above it is the base plate 54, which has a large number of small, circular openings 53 with cross sections similar to Laval nozzles. The base plate 54 is part of the compressed air chamber 17 arranged above it. The compressed air chamber 17 is connected to the two symmetrically arranged wind boilers 43 via the generously dimensioned lines 42 in order to increase the output volume. The pressure in the compressed air chamber is 5 bar. The air-permeable frame 45, which carries the elastic valve tappets 52, 65, is located in the compressed air chamber 17. The generously dimensioned bores 14, 57, 67 in the frame 45 enable the compressed air to flow without throttling. The elastic valve lifters 52, 65 close the openings 53 in the base plate 54. The frame 45 is fastened to the piston 41. The piston 41, which causes the opening and closing of the base plate openings 53, slides in a cylinder, the lower space 21 of which is an integral part of the compressed air chamber 17. Likewise, the piston cavity 20 is an integral part of the compressed air chamber 17. A vertically movable flange 11 is suspended from four pneumatic cylinders 44 on the outer edge of the housing 15. The pneumatic cylinders are under constant pressure on the piston side and thus act as a pneumatic spring. In the starting position, the pistons hit the stops 16 pressed. The flange 11 has the task of producing a pressure-tight connection between the housing 15 and the filling frame 8 with its seals 9 and 13. The seal 9 is a static seal, while the seal 13 can be activated with compressed air. In the non-activated state, the seal 13 withdraws behind the inner surface of the flange and the housing 15 can be moved through the flange 11 without contact with the play 46. In the activated state, the seal 13 is pressed against the outer wall of the housing 15.

Fig. 1 linker Halbschnitt zeigt die Vorrichtung in der Ausgangsstellung. Die Modellplatte 5 mit Modell 5a, Formkasten 7 und Füllrahmen 8 ist über die Rollenbahn 4 unter die Bodenplatte 54 gefahren. Der Formstoff 6 ist bis zur Oberfläche 50 lose und gleichmäßig aufgeschüttet. Mit dem Hubtisch 3 wird die Modellplatte 5 von der Rollenbahn 4 abgehoben und mit der weiteren Aufwärtsbewegung wird der Füllrahmen 8 unter den Flansch 11 gedrückt, der dann gegen den pneumatischen Federdruck 44 ebenfalls nach oben bewegt wird. Die Aufwärtsbewegung wird soweit geführt bis die Bodenplatte 54 die lose Formstoffoberfläche 50 zur Verminderung ihres Luftporenvolumens leicht angedrückt hat. Danach wird durch eine Abwärtsbewegung die lose Formstoffoberfläche 50 in eine definierte Distanz 49 zur Bodenplatte 54 gebracht (Schußposition). Es kann aber auch darauf verzichtet werden, die Formstoffoberfläche leicht anzudrücken. Die Aufwärtsbewegung wird dann direkt bis zur definierten Distanz 49 (Schußposition) geführt.Fig. 1 left half section shows the device in the starting position. The model plate 5 with model 5a, molding box 7 and filling frame 8 is moved over the roller conveyor 4 under the base plate 54. The molding material 6 is loosely and evenly piled up to the surface 50. With the lifting table 3, the model plate 5 is lifted off the roller conveyor 4 and with the further upward movement the filling frame 8 is pressed under the flange 11, which is then also moved upwards against the pneumatic spring pressure 44. The upward movement is carried out until the base plate 54 has slightly pressed the loose molding material surface 50 to reduce its air pore volume. The loose molding material surface 50 is then brought into a defined distance 49 from the base plate 54 by a downward movement (firing position). However, it is also possible to dispense with gently pressing the surface of the molding material. The upward movement is then carried out directly up to the defined distance 49 (shot position).

Fig. 1 rechter Halbschnitt zeigt die Vorrichtung in Schußposition, wobei mit "Schuß" das schlagartige Austreten der Druckluft gemeint ist. In dieser Position wird zunächst die Dichtung 13 aktiviert. Der pneumatische Federdruck 44 bewirkt eine Anpressung der Dichtung 9. Außerdem wirkt dieser pneumatische Federdruck der Kraft entgegen, die durch die Druckeinwirkung auf den Spalt 48 entsteht. Das System ist damit druckdicht verschlossen und die Druckwellenverdichtung kann freigegeben werden. Das Gehäuse der Druckluftkammer 17 ist über den Kopfrahmen 22, den Säulen 55, dem Grundrahmen 1 und dem Zylinder 2 mit Hubtisch 3 zu einem kraftschlüssigen System verbunden.Fig. 1 right half section shows the device in the firing position, with "firing" means the sudden escape of the compressed air. In this position, the seal 13 is first activated. The pneumatic spring pressure 44 presses the seal 9. In addition, this pneumatic spring pressure counteracts the force that is created by the pressure acting on the gap 48. The system is then sealed pressure-tight and the compression of the pressure waves can be released. The housing of the compressed air chamber 17 is connected via the head frame 22, the columns 55, the base frame 1 and the cylinder 2 to the lifting table 3 to form a force-locking system.

Durch Anheben des Kolbens 41 werden über den biegesteifen Rahmen 45 alle Auslaßbohrungen 53 gleichzeitig geöffnet. Weil zum Öffnen eines drosselfreien Querschnittes nur ein kleiner Hub von wenigen Millimetern (d/4 einer Auslaßbohrung) erforderlich ist und weil weitere noch zu beschreibende, vorteilhafte Kriterien vorliegen, werden nur wenige Millisekunden zum Öffnen eines drosselfreien Querschnittes benötigt. Die Druckluft kann somit aus den Öffnungen 53 der Bodenplatte 54, die insgesamt einen sehr großen Querschnitt ausmachen, in wenigen Millisekunden austreten. Die kreisförmigen Öffnungen 53, die gemäß Fig. 4 in einem Rastersystem sehr nah beieinanderliegen, haben lavaldüsenähnliche Querschnitte. Durch eine entsprechende Ausbildung der Düse wird erreicht, daß der Luftstrahl am Ausgang der Düse leicht aufplatzt. Dies hat zur Folge, daß die nah nebeneinander austretenden Luftstrahle sich vermischen und im weiteren Verlauf der Distanz 49 eine Druckwelle bilden. Die Druckwelle trifft mit hoher Geschwindigkeit auf die lose Formstoffoberfläche 50 auf. Der Formstoff 6 wird beschleunigt und durch nachfolgendes Abbremsen auf der Modellplatte 5 verdichtet. Die Druckluft entspannt dabei in dem geschlossenen System mit adiabatischem Verlauf auf einen definierten Enddruck. Die stärkste Verdichtung entsteht im Bereich der Modellplatte, weil diese als starre und unnachgiebige Masse die stärkste Verzögerung der Formstoffmassenteilchen bewirkt und weil hier noch die vollständige Masse des Formstoffes wirksam ist. Im Verlauf zur Oberfläche 51 hin nimmt die Formstoffverdichtung leicht ab, weil die Formstoffmasse und somit die Massenenergie abnimmt und weil die oberen Schichten des Formstoffes nicht mehr unmittelbar auf der starren Modellplatte sondern in den Zwischenschichten des Formstoffes abgebremst werden. Es entsteht hierdurch der charakteristische und gießtechnisch ideale Formhärteverlauf. Falls die Formhärte der Oberflächenschicht 51 nicht ausreicht, um Gießtümpel und Gießtrichter einzufräsen, so kann die Formstoffoberfläche 51 nachverdichtet werden ohne jedoch den idealen Formhärteverlauf wesentlich zu beeinflussen. Hierzu wird nach dem Verschließen der Bodenplattenöffnungen 53 das Ventil 12 geöffnet. Der Restdruck über der Formstoffoberfläche 51 wird dabei wieder auf den Systemdruck 6 bar erhöht und dieser wird für eine kurze Zeit als statischer Druck über der Formstoffoberfläche 51 gehalten. Über das Ventil 10 wird der Raum zwischen Bodenplatte 54 und Formstoffoberfläche 51 wieder drucklos gemacht. Eine weitere Möglichkeit der Nachverdichtung besteht darin, daß die Formstoffoberfläche 51 mittels Hubtisch 3 gegen die Bodenplatte 54 gedrückt wird. Dies geschieht, indem zuvor der Restdruck über der Formstoffoberfläche 51 durch das Ventil 10 abgelassen und die Dichtung 13 entspannt wird. Die wirksame Preßfläche 59 zwischen den Öffnungen 53 beträgt ca. 50 % der gesamten Formstoffoberfläche 51.By lifting the piston 41, all the outlet bores 53 are opened simultaneously via the rigid frame 45. Because only a small stroke of a few millimeters (d / 4 of an outlet bore) is required to open a throttle-free cross-section and because there are other advantageous criteria to be described, only a few milliseconds are required to open a throttle-free cross-section. The compressed air can thus emerge from the openings 53 of the base plate 54, which together make up a very large cross section, in a few milliseconds. The circular openings 53, which according to FIG. 4 are very close together in a grid system, have cross sections similar to Laval nozzles. Appropriate training of the nozzle ensures that the air jet bursts slightly at the outlet of the nozzle. The result of this is that the air jets emerging close to one another mix and form a pressure wave as the distance 49 progresses. The pressure wave hits the loose molding material surface 50 at high speed. The molding material 6 is accelerated and compressed on the model plate 5 by subsequent braking. The compressed air relaxes in the closed system with an adiabatic course to a defined final pressure. The greatest compression occurs in the area of the model plate because this, as a rigid and unyielding mass, causes the greatest deceleration of the molding material particles and because the full mass of the molding material is still effective here. The compression of the molding material decreases slightly in the course of the surface 51 because the molding material mass and thus the mass energy decrease and because the upper layers of the molding material are no longer braked directly on the rigid model plate but in the intermediate layers of the molding material. This creates the characteristic and ideal casting technology in terms of mold hardness. If the hardness of the surface of the surface layer 51 is not sufficient to mill the pouring basin and the casting funnel, the molding material surface 51 can be densified without, however, significantly influencing the ideal shape hardness curve. For this purpose, the valve 12 is opened after the bottom plate openings 53 have been closed. The residual pressure above the molding material surface 51 is again increased to the system pressure 6 bar and this is kept as a static pressure above the molding material surface 51 for a short time. The space between base plate 54 and molding surface 51 is depressurized again via valve 10. Another possibility of post-compaction is that the molding material surface 51 is pressed against the base plate 54 by means of a lifting table 3. This is done by previously releasing the residual pressure above the molding material surface 51 through the valve 10 and releasing the seal 13. The effective pressing surface 59 between the openings 53 is approximately 50% of the total molding surface 51.

Nach dem Verdichtungsvorgang wird der Hubtisch wieder abgesenkt, wodurch sich die Modellplatte 5 mit Modell 5a, Formkasten 7, Füllrahmen 8 und der verdichteten Form wieder auf die Rollenbahn 4 absetzt. Die Modellplatte 5 mit den aufliegenden Einheiten wird heraus gefahren. Gleichzeitig wird von der entgegengesetzten Seite die andere Modellhälfte unter die Bodenplatte 54 gefahren und mit Anheben des Hubtisches 3 beginnt ein neuer Verdichtungszyklus. Dieses vorteilhafte Anordnungsbeispiel einer Druckgaskammer für zwei Modellhälften ist in Fig. 6 dargestellt. Darüberhinaus sind viele andere Anordnungsvarianten möglich.After the compression process, the lifting table is lowered again, as a result of which the model plate 5 with model 5a, molding box 7, filling frame 8 and the compacted mold is again placed on the roller conveyor 4. The model plate 5 with the units lying on it is moved out. At the same time, the other half of the model is moved under the base plate 54 from the opposite side and a new compression cycle begins when the lifting table 3 is raised. This beneficial Arrangement example of a compressed gas chamber for two model halves is shown in Fig. 6. In addition, many other arrangement variants are possible.

Die Summe der Querschnittsflächen 47, 60 und die Querschnittsfläche des Kolbens 41 bilden zusammen ein Differentialkolbensystem. Die Querschnittsfläche des Kolbens 41 ist größer als die Summe aller Querschnittsflächen 47, 60. In den Zylinderräumen 21 und 24 sowie über den Ventilstößeln 52 stehen die gleichen Druckwerte der Druckluftkammer 17 an. Hieraus ergibt sich eine resultierende Kraft, die die Ventilstößel 52, 65 auf ihren Sitz drücken. Diese Kraft entspricht dem Produkt aus der Summe aller Querschnittsflächen 47, 60 und dem Druck der Druckluftkammer 17. Wird der Druck im Zylinderraum 24 auf atmosphärischen Druck entspannt, dann ergibt sich eine nach oben gerichtete Kraft, weil die Querschnittsfläche des Kolbens 41 größer ist als die Summe aller Querschnittsflächen 47, 60. Im Zeitpunkt, in dem die Ventilstößel zu öffnen beginnen, entspricht diese Kraft dem Produkt aus der Differenzquerschnittsfläche und dem Druck der Druckluftkammer. Im weiteren Verlauf des Ventilstößelhubes erhöht sich diese Kraft, weil durch das Freiwerden der Ventilstößel die gesamte Querschnittsfläche des Kolbens 41 wirksam wird. Zu berücksichtigen ist jedoch hierbei, daß der Druck entsprechend der Volumenverhältnisse und des adiabatischen Verlaufes von 5 bar auf ca. 3,5 bar abnimmt. Die Flächenverhältnisse sind so ausgelegt, daß im Zeitpunkt des Hubbeginns der Ventilstößel eine Kraft zur Verfügung steht, die die Überwindung des Eigengewichtes und der Reibung sowie die erforderliche Beschleunigung sicherstellt. Die weitere Krafterhöhung kann somit eine zusätzliche Beschleunigung bewirken, was wiederum für das schnelle Öffnen von Bedeutung ist.The sum of the cross-sectional areas 47, 60 and the cross-sectional area of the piston 41 together form a differential piston system. The cross-sectional area of the piston 41 is greater than the sum of all cross-sectional areas 47, 60. The same pressure values of the compressed air chamber 17 are present in the cylinder chambers 21 and 24 and above the valve tappets 52. This results in a resultant force which the valve lifters 52, 65 press onto their seat. This force corresponds to the product of the sum of all cross-sectional areas 47, 60 and the pressure of the compressed air chamber 17. If the pressure in the cylinder space 24 is released to atmospheric pressure, an upward force results because the cross-sectional area of the piston 41 is larger than that Sum of all cross-sectional areas 47, 60. At the point in time at which the valve tappets begin to open, this force corresponds to the product of the differential cross-sectional area and the pressure of the compressed air chamber. In the further course of the valve tappet stroke, this force increases because the entire cross-sectional area of the piston 41 becomes effective as the valve tappets become free. However, it should be taken into account here that the pressure decreases from 5 bar to approx. 3.5 bar in accordance with the volume ratios and the adiabatic curve. The area ratios are designed in such a way that a force is available at the start of the stroke of the valve lifter, which ensures that the dead weight and the friction are overcome as well as the required acceleration. The further increase in force can thus cause an additional acceleration, which in turn is important for the rapid opening.

Die Kolbengleitflächen 18 und 23 sind mit Führungsbändern versehen, die einen sehr niedrigen Reibwert haben und hoch verschleißfest sind. Sie verhindern außerdem eine metallische Berührung des Kolben- und Zylindermaterials. Dichtungen sind an den Kolbengleitflächen 18 und 23 nicht erforderlich, weil der Kolben 41 im geschlossenen Zustand der Öffnungen 53 beidseitig vom gleichen Systemdruck beaufschlagt wird. Der geöffnete Zustand, indem der Zylinderraum 24 über die reichlich dimensionierten Schnellentlüfterventile 36 auf atmosphärischen Druck entlastet wird, dauert maximal nur 1 Sekunde. Die dabei auftretenden geringfügigen Leckagen werden in Kauf genommen, weil sie die Funktion nicht beeinflussen.The piston sliding surfaces 18 and 23 are provided with guide bands which have a very low coefficient of friction and are highly wear-resistant. They also prevent metallic contact between the piston and cylinder material. Seals are not required on the piston sliding surfaces 18 and 23 because the piston 41 is acted upon on both sides by the same system pressure when the openings 53 are closed. The open state, in which the cylinder chamber 24 is relieved to atmospheric pressure via the generously dimensioned quick-exhaust valve 36, lasts for a maximum of only 1 second. The minor leaks that occur are accepted because they do not affect the function.

Nachfolgend werden nochmals die Kriterien zusammengefaßt, die für das schnelle, nur wenige Millisekunden dauernde Öffnen von besonderer Bedeutung sind:

  • - kleiner, nur wenige Millimeter langer Hub
  • - Kolbenflächen 18 und 23 ohne Dichtung
  • - Kolbenflächen 18 und 23 mit reibungsarmen Führungsbändern
  • - auf Grund des kleinen Hubes nur ein kleiner Zylinderraum 24, der über die Schnellentlüftungsventile 36 sehr schnell entlüftet werden kann.
  • - Druck steht im Zylinderraum 21 als potentielle Energie an
  • - große Beschleunigungskraft zum Anheben des Systems unterstützt durch die Federwirkung der elastischen Ventilstößel 52, 65
  • - Öffnen der Ventilsitze mit einer definierten Anfangsgeschwindigkeit größer als Null (ca. 1 m/sek)
In the following, the criteria are summarized again, which are of particular importance for the quick opening that only lasts a few milliseconds:
  • - Small stroke, only a few millimeters long
  • - Piston surfaces 18 and 23 without seal
  • - Piston surfaces 18 and 23 with low-friction guide bands
  • - Due to the small stroke, only a small cylinder space 24, which can be vented very quickly via the quick exhaust valves 36.
  • - Pressure is present in the cylinder space 21 as potential energy
  • - Large acceleration force for lifting the system supported by the spring action of the elastic valve lifters 52, 65
  • - Opening the valve seats with a defined initial speed greater than zero (approx. 1 m / sec)

Die hohe Beschleunigung führt trotz des geringen Hubes zu einer hohen Kolbengeschwindigkeit. Um bei Hubende ein zu hartes Aufschlagen des Kolbens 41 zu vermeiden, ist im Zylinderraum 24 eine Federdämpfung 39 eingebaut, die den Kolben 41 über einen definierten Bremsweg zum Stillstand bringt. Auf der Kolbenfläche ist eine entsprechend belastbare Kunststoffscheibe 40 aufgebracht, die ein metallisches Aufschlagen des Kolbens auf die Fläche der Federdämpfung 39 verhindert. Wenn der Kolben 41 den zum Öffnen des gesamten Auslaßquerschnittes erforderlichen Hub 39a zurückgelegt hat, schlägt die Kunststoffscheibe 40 am Flansch 39 an. Die Federn 38 haben in dieser Ausgangsstellung nur eine sehr geringe Vorspannung, sodaß der Bremsbeginn annähernd stoßfrei ist. Die Federn 38 sind so ausgelegt, daß sie den Kolben 41 zum Stillstand bringen, bevor er den Zylinderflansch 25 berührt.The high acceleration leads to a high piston speed despite the low stroke. In order to prevent the piston 41 from striking too hard at the end of the stroke, a spring damping 39 is installed in the cylinder space 24, which brings the piston 41 to a standstill over a defined braking distance. A correspondingly resilient plastic disk 40 is applied to the piston surface, which prevents the piston from striking metal onto the surface of the spring damping 39. When the piston 41 has covered the stroke 39a required to open the entire outlet cross section, the plastic disk 40 strikes the flange 39. In this starting position, the springs 38 have only a very slight pretension, so that the start of braking is almost bumpless. The springs 38 are designed so that they bring the piston 41 to a standstill before it contacts the cylinder flange 25.

Die Führungen 56, die auch als Rollen ausgebildet sein können, verhindern ein Verdrehen des Rahmens 45. Sie sind mit einem geringfügigem Spiel eingestellt, sodaß die Hubbewegung des Rahmens nicht behindert wird.The guides 56, which can also be designed as rollers, prevent the frame 45 from rotating. They are set with a slight play so that the lifting movement of the frame is not hindered.

Die Ventilstößel 52, 65 bestehen aus einem elastischen Material 64 (z.B. Gummi), welches auf einem Stahlkern 63 aufvulkanisiert ist. Der Stahlkern 63 und der Schraubenkopf 62 stützen das elastische Material gegen den nach Außen wirkenden Systemdruck ab. Die Flächen 68 und 61, 70 verlaufen geanau planparallel. Die Länge 69 der Ventilstößel 52, 65 entspricht in einem definierten Toleranzbereich diesem planparallelen Abstand. Toleranzdifferenzen werden durch die Elastizität der Ventilstößel angeglichen. Die genaue Länge 69 wird innerhalb des vorgegebenen Toleranzbereiches gefertigt. Die Gummimasse 64a stellt eine durch die Zuhaltekraft zusammengedrückte Feder dar, die mit ihrer Vorspannung das Anheben des Kolbens 41 und des Rahmens 45 beim Öffnungsvorgang unterstützt und die außerdem das Abheben der Ventilstößel 52, 65 vom Ventilsitz mit einer definierten Anfangsgeschwindigkeit größer als Null bewirkt. Für das Auswechseln der Ventilstößel 52, 65 wird das Gehäuseunterteil 15 am Schnellverschluß 19 gelöst und mit dem Hubtisch 3 abgesenkt und mittels einer einfachen .Palette über die Rollenbahn 4 seitlich weggefahren. Die Ventilstößel 52, 65 sind dann von unten frei zugänglich.The valve lifters 52, 65 consist of an elastic material 64 (for example rubber) which is vulcanized onto a steel core 63. The steel core 63 and the screw head 62 support the elastic material against the outward system pressure. The surfaces 68 and 61, 70 run exactly plane-parallel. The length 69 of the valve lifters 52, 65 corresponds to this plane-parallel distance within a defined tolerance range. Tolerance differences are adjusted by the elasticity of the valve lifters. The exact length 69 is manufactured within the specified tolerance range. The rubber mass 64a represents a spring compressed by the locking force, which with its pretension assists the lifting of the piston 41 and the frame 45 during the opening process and which also causes the valve lifters 52, 65 to be lifted off the valve seat at a defined initial speed greater than zero. To replace the valve lifters 52, 65, the lower housing part 15 is released on the quick-release fastener 19 and lowered with the lifting table 3 and by means of a simple one .Pallet moved sideways over the roller conveyor 4. The valve lifters 52, 65 are then freely accessible from below.

Fig. 1 zeigt neben der mechanischen Vorrichtung auch das pneumatische Steuerungssystem. Die Druckluft wird vom Netz mit dem Nenndruck 6 bar über den Absperrhahn 27 und über das Filter 26 eingespeist. Die Arbeitsluft wird von dort über das Ventil 30 und über den Druckregler 31 den zwei Windkesseln 43 zugeführt. Die Steuerluft wird hinter dem Druckluftöler 29 abgenommen und über die Ventile 32 und 34 dem Zylinderraum 24 zugeführt. Die Schnellentlüfterventile 36 dienen zum schnellen Entlüften des Zylinderraumes 24. Das Ventil 12 dient zum Nachverdichten der Formstoffoberfläche 51 und das Ventil 10 dient zum Entlasten des Raumes über der Formstoffoberfläche 51. Ventil 37 ist das Hauptsicherheitsventil. Mit dem Druckregelventil 31 wird der Arbeitsdruck auf 5 bar gehalten.1 shows the pneumatic control system in addition to the mechanical device. The compressed air is fed in from the network with the nominal pressure 6 bar via the shut-off valve 27 and the filter 26. From there, the working air is supplied to the two wind boilers 43 via the valve 30 and the pressure regulator 31. The control air is removed behind the compressed air lubricator 29 and fed to the cylinder chamber 24 via the valves 32 and 34. The quick breather valves 36 are used for quick venting of the cylinder space 24. The valve 12 is used for post-compression of the molding surface 51 and the valve 10 is used for relieving the space above the molding surface 51. Valve 37 is the main safety valve. With the pressure control valve 31, the working pressure is kept at 5 bar.

In der Ausgangsstellung ist das Ventil 34 stromlos geöffnet (Sicherheitsschaltung), das Ventil 32 stromlos geschlossen und das Ventil 30 stromführend geöffnet. Die Ventile 10, 12 und 28 sind stromlos geschlossen. In dieser Schaltstellung steht der Druck der Druckluftkammer 17 und der Windkessel 43 über das Rückschlagventil 33, dem Ventil 34 und den Schnellentlüfterventilen 36 im Zylinderraum 24 an. Der Kolben 41 wird nach unten gedrückt und die Ventilstößel 52, 65 verschließen somit die Öffnungen 53. Wenn die Vorrichtung sich in Schußposition befindet, wird zunächst das Ventil 28 geschaltet und somit die Dichtung 13 aktiviert. Danach wird das Ventil 34 eingeschaltet und das Ventil 30 ausgeschaltet. Das Ventil 30 unterbricht die weitere Zufuhr der Arbeitsluft. Das Ventil 34 unterbricht die Zufuhr der Steuerluft und entlastet gleichzeitig die Schnellentlüfterventile 36. Über einen großen und drosselfreien Querschnitt der Schnellentlüfterventile 36 und der nachgeschalteten Schalldämpfer 35 wird der Zylinderraum 24 in sehr kurzer Zeit entlastet. Der Kolben 41 hebt die Ventilstößel 52, 65 an und die Bodenplattenöffnungen 53 werden in wenigen Millisekunden freigegeben. Die Druckluft tritt aus der Druckluftkammer aus und verdichtet - wie bereits beschrieben - den Formstoff. Der Druck sinkt dabei entsprechend der Volumensveränderung und unter Berücksichtigung des adiabatischen Verlaufes von 5 bar auf ca. 3,5 bar ab. Nach der Druckwellenverdichtung werden die Ventile 32 und 34 geöffnet. Der Kolben 41 wird mit dem Netzdruck von 6 bar nach unten bewegt und die Ventilstößel 52, 65 verschließen wieder die Öffnungen 53. Zum Nachverdichten wird das Ventil 12 für kurze Zeit geöffnet. Danach wird das Ventil 32 geschlossen und das Ventil 30 geöffnet, wodurch die Druckluftkammer 17 und die Windkessel 43 wieder auf den Ausgangsdruck von 5 bar gebracht werden und der Zylinderraum 24 wieder vom 6 bar-System auf das 5 bar-System der Druckluftkammer 17 geschaltet wird. Zum Entlasten des Druckraumes über der verdichteten Formstoffoberfläche 51 wird das Ventil 10 kurzzeitig geöffnet. Danach wird die Dichtung 13 über das Ventil 28 entlastet. Der Verdichtungsvorgang ist beendet und der Hubtisch 3 kann die Modellplatte 5 wieder auf die Rollenbahn 4 absenken.In the starting position, valve 34 is open when de-energized (safety circuit), valve 32 is closed when de-energized, and valve 30 is opened when current is applied. The valves 10, 12 and 28 are closed when de-energized. In this switching position, the pressure of the compressed air chamber 17 and the wind chamber 43 is present in the cylinder chamber 24 via the check valve 33, the valve 34 and the quick-vent valve 36. The piston 41 is pressed down and the valve tappets 52, 65 thus close the openings 53. When the device is in the firing position, the valve 28 is first switched and thus the seal 13 is activated. Then valve 34 is turned on and valve 30 is turned off. The valve 30 interrupts the further supply of the working air. The valve 34 interrupts the supply of the control air and at the same time relieves the pressure on the quick breather valves 36. The cylinder space 24 is relieved in a very short time via a large and throttle-free cross section of the quick breather valves 36 and the downstream silencers 35. The piston 41 lifts the valve lifters 52, 65 and the base plate openings 53 are released in a few milliseconds. The compressed air emerges from the compressed air chamber and - as already described - compresses the molding material. The pressure drops in accordance with the change in volume and taking into account the adiabatic curve from 5 bar to approx. 3.5 bar. After the pressure wave compression, the valves 32 and 34 are opened. The piston 41 is moved downwards with the network pressure of 6 bar and the valve tappets 52, 65 close the openings 53 again. The valve 12 is opened for a short time for subsequent compression. Thereafter, the valve 32 is closed and the valve 30 is opened, as a result of which the compressed air chamber 17 and the air boiler 43 are brought back to the initial pressure of 5 bar and the cylinder chamber 24 is switched again from the 6 bar system to the 5 bar system of the compressed air chamber 17 . To relieve the pressure chamber above the compressed molding material surface 51, the valve 10 is opened briefly. Then the seal 13 is relieved via the valve 28. The compression process is finished and the lifting table 3 can lower the model plate 5 back onto the roller conveyor 4.

Fig. 7 zeigt eine Ausführungsvariante, die bei besonders großflächigen Formstoffoberflächen eingesetzt werden kann. Die Auslaßöffnungen 71 sind hierbei entsprechend groß dimensioniert und jeder Ventilstößel 73 hat einen eigenen Antriebskolben 75. Ventilstößel 73 und Antriebskolben 75 bilden zusammen ein Differentialkolbensystem mit der gleichen Wirkungsweise wie auf Seite 8 beschrieben. Hinsichtlich der Düsenform, der Druckwellenausbildung und der definierten Distanz 49 gilt sinngemäß das Gleiche wie vorher erläutert. Eine Kugelgelenkaufhängung 74 mit einem kleinen, allseitigen Winkelanschlag stellt sicher, daß der großflächige Ventilteller 73 planparallel auf der Dichtfläche 72 aufliegt. Die konischen Hauben 76 vermindern den Strömungswiderstand.FIG. 7 shows an embodiment variant which can be used with particularly large surfaces of molding material. The outlet openings 71 are dimensioned accordingly large and each valve tappet 73 has its own drive piston 75. Valve tappet 73 and drive piston 75 together form a differential piston system with the same mode of operation as described on page 8. With regard to the nozzle shape, the pressure wave formation and the defined distance 49, the same applies as previously explained. A ball joint suspension 74 with a small, all-round angular stop ensures that the large-area valve disk 73 rests plane-parallel on the sealing surface 72. The conical hoods 76 reduce the flow resistance.

Claims (21)

1. A process for compressing granular moulding materials such as foundry moulding sand by means of a pressure wave of gaseous medium such as compressed air acting at high speed on the surface of the loose moulding material, with the compression medium emerging uniformly from Laval-type nozzles that are arranged close together in a raster system in a bottom plate (54) over the entire surface of the moulding material (50), characterized in that the single air jets burst open at the nozzle outlet so that the air jets emerging close to each other intermingle and impinge vertically as well as uniformly at all points as a pressure wave on the surface (50) of the loose moulding material.
2. Process according to claim 1, characterized in that the bottom plate (54) and/or the surface of the loose moulding material (50) - the latter effected by the moulding plate (5) - can be moved towards each other in a vertical direction.
3. Process according to claims 1 and 2, characterized in that the surface (50) of the loose moulding material can be lightly pressed by the bottom plate (54) prior to exposure to the pressure wave in order to reduce the air voids present in said surface.
4. Process according to claims 1 and 2, characterized in that the bottom plate (54) is brought to the surface (50) of the loose moulding material at a defined distance (49) prior to exposure to the pressure wave, in order to reach a uniform, frontal formation of the pressure wave.
5. Process according to claims 1 and 2, characterized in that after the pressure wave compression a thin, somewhat less compressed surface layer (51) can be re-compressed by repressing with the bottom plate (54) and/or by increasing the pressure of the gas over the firm moulding material surface (51).
6. Device for implementing the process according to claim 1, consisting of a table (3) holding a moulding plate (5), of a moulding flask (7) and filling frame (8) supported on it, of a pressure gas chamber (17) located above it and of a bottom plate (54) with openings (53) positioned close to each other in a raster system as a component part of the pressure gas chamber (17), characterized in that flexible valve lifters (52, 65) close to the openings (53) that are positioned close to each other in a raster system in the bottom plate (54), that the valve lifters (52, 65) are attached to a rigid and gas-permeable frame (45) and that the frame (45) is attached to a piston (41) that is directly under the influence of the gas pressure of the pressure gas chamber (17) and whose cross-sectional area is greater than the sum total of the cross-sections of all openings (47, 60) in the bottom plate (54).
7. Device according to claim 6, characterized in that the piston (41) that effects opening and closing of the openings (53) in the bottom plate (54) is pressurized in both directions by the gas pressure of the pressure gas chamber (17) and in that no external source of energy is therefore necessary.
8. Device according to claims 6 and 7, characterized in that the piston (41) is raised in a few milliseconds by the rapid pressure release lasting a few milliseconds in the cylinder compartent (24) of the piston (41) through the gas pressure available as potention energy in the cylinder compartment (21) and through the supporting spring action of the flexible valve lifter (52, 65).
9. Device according to claims 6 to 8 inclusive, characterized in that the sliding surfaces (18) and (23) of the pistons can be without seals.
10. Device according to claims 6 to 9 inclusive, characterized in that the cavity (20) of the piston and the cavity (21) of the cylinder are integrated component parts of the pressure gas chamber (17).
11. Device according to claim 6, characterized in that the sealing surfaces (61) of the flexible valve lifter (65) are plane-parallel to the inner (70) the bottom plate (54) in order to attain a throttle- free output cross-section with the smallest possible stroke (e.g. d/4 of a circular opening (60).
12. Device according to claims 6 and 11, characterized in that the bottom plate (54) has a large number of openings (53) with cross-sections like that of a Laval nozzle that are arranged in a rectangular raster system and are formed in such a way that the air jets emerging at supersonic speed burst open lightly at the nozzle outlets and intermingle in the course of the defined distance (49), causing a frontal pressure wave to be formed.
13. Device according to claims 11 and 12, characterized in that the frame (45) between the valve lifters (52, 65) that run conically upwards has openings (14, 57, 67) that have a greater cross-section than the openings (47, 60) in the bottom plate (54) and that the cross-sections (58) between the valve lifters (52, 65) are the same as or greater than those of the openings (14, 57, 67) of the frame (45).
14. Device according to claims 6 to 13 inclusive, characterized in that the piston (41) has to cover only a very small stroke (d/4 of one circular opening (47, 60) in order to open the entire outlet cross-section in the bottom plate (54) throttle- free, which is of significance for the necessary, rapid opening of the entire outlet cross-section within a period of a few milliseconds.
15. Device according to claims 4, 11 and 12, characterized in that the valve cone (52, 65) consists of an elastic material (64), e.g. rubber, that is vulcanized onto a steel core (63) and that the screw head (62) and the steel core (63) support the elastic material (64) against the effect of the gas pressure.
16. Device according to one of the claims 6 to 15 inclusive, characterized in that a flange (11) suspended on the housing (15) produces a pressure-tight connection between the housing (15) and the filling frame (8) and that the flange (11) is pressed onto the filling frame (8) by a pneumatic spring force (44).
17. Device according to claim 16, characterized in that the flange (11) has a static seal (9) to the filling frame (8) and also a seal (13) to the housing (15), said seal (13) capable of being activated by compressed gas.
18. Device according to claims 16 and 17, characterized in that the activatable seal (13) is let into a recess of the flange (11) and withdraws behind the inner surface of the flange in non- activated state because of its elasticity, as a result of which the housing (15) can be moved contact-free with a defined clearance (46) through the flange (11).
19. Device according to one of the claims 6 to 18 inclusive, characterized in that the flange (11) can, with a defined dimension (49), also be permanently connected with the housing (15) and has only the static seal (9).
20. Device according to claims 6 to 12 inclusive, characterized in that each valve lifter (73) can also have its own driving piston (75) according to claims 6 - 12 inclusive and that the valve lifter (73) that is formed for a large outlet opening (71) has a ball-and-socket joint suspension (74) with a defined, polydirectional swing that permits plane-parallel positioning of the sealing surface (72).
21. Device according to claim 15, characterized in that the rubber mass (64a - Fig. 5) that is supported by the screw head (62) against the acting gas pressure represents a spring compressed by the locking pressure that due to its initial stress assists the lifting of the piston (41) and of the frame (45) in the opening process and, as a result of the spring excursion, causes the mass of the piston (41) and of the frame (45) initially to start moving upwards before the valve lifters (52, 65) rise at a defined initial speed in excess of zero from the valve seat, as a result of which the entire outlet cross-section is opened in a few milliseconds.
EP84108988A 1983-08-02 1984-07-28 Method of and installation for compacting granular moulding materials, for example foundry mould sand Expired - Lifetime EP0139119B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT84108988T ATE37305T1 (en) 1983-08-02 1984-07-28 METHOD AND DEVICE FOR COMPRESSING GRANULAR MOLDING MATERIALS, e.g. FOUNDRY MOLDING SAND.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3327822 1983-08-02
DE19833327822 DE3327822A1 (en) 1983-08-02 1983-08-02 METHOD AND DEVICE FOR COMPRESSING GRAIN-MOLDED MOLDING SUBSTANCES e.g. FOUNDRY MOLD SAND

Publications (3)

Publication Number Publication Date
EP0139119A1 EP0139119A1 (en) 1985-05-02
EP0139119B1 true EP0139119B1 (en) 1988-09-21
EP0139119B2 EP0139119B2 (en) 1996-11-13

Family

ID=6205541

Family Applications (1)

Application Number Title Priority Date Filing Date
EP84108988A Expired - Lifetime EP0139119B2 (en) 1983-08-02 1984-07-28 Method of and installation for compacting granular moulding materials, for example foundry mould sand

Country Status (3)

Country Link
EP (1) EP0139119B2 (en)
AT (1) ATE37305T1 (en)
DE (2) DE3327822A1 (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4673020A (en) * 1983-10-21 1987-06-16 Equipment Merchants International Inc. Foundry molding machine and method
DE3937254A1 (en) * 1989-11-09 1991-05-16 Badische Maschf Gmbh DEVICE FOR COMPRESSING FOUNDRY MOLDING MATERIALS
AU644702B2 (en) * 1990-12-14 1993-12-16 Sintokogio Ltd. Compressed air blowing apparatus for use in green sand mold molding facility
DE19848048A1 (en) * 1998-10-19 2000-05-04 Josef Mertes Method and device for compressing moldings z. B. Foundry molding sand
RU2472600C1 (en) * 2011-05-24 2013-01-20 Закрытое Акционерное Общество "Литаформ" Method of producing moulds and device to this end

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1961234C3 (en) * 1969-12-05 1975-02-06 Kramatorskij Nautschno-Issledowatel' Skij I Projektno-Technologitscheskij Institut Maschinostrojenija, Kramatorsk (Sowjetunion) Method and device for compacting casting molding compounds
DE2608740C2 (en) * 1976-03-03 1978-05-11 Eugen Dipl.-Ing. 8871 Burtenbach Buehler Process for compacting molding sand
AT381877B (en) * 1978-12-15 1986-12-10 Fischer Ag Georg METHOD AND DEVICE FOR COMPRESSING GRANULAR SUBSTANCES, IN PARTICULAR FOUNDRY MOLD
CH642288A5 (en) * 1980-02-18 1984-04-13 Fischer Ag Georg METHOD AND DEVICE FOR COMPRESSING MOLDING MATERIAL, ESPECIALLY FOR CASTING MOLDS.
EP0036434A1 (en) * 1980-03-25 1981-09-30 Eugen Dipl.-Ing. Bühler Method and device for compacting casting moulds
DE3025993C2 (en) * 1980-07-09 1983-11-10 Sintokogio, Ltd., Nagoya, Aichi Molding device for explosive compression of a sand-like filler material
DE3238802A1 (en) * 1981-12-05 1983-06-16 VEB Kombinat Gießereianlagenbau und Gußerzeugnisse - GISAG -, DDR 7031 Leipzig Apparatus for producing sand moulds and sand cores
EP0084627B1 (en) * 1981-12-28 1986-05-07 BMD Badische Maschinenfabrik Durlach GmbH Device for compacting foundry moulding material

Also Published As

Publication number Publication date
EP0139119A1 (en) 1985-05-02
ATE37305T1 (en) 1988-10-15
EP0139119B2 (en) 1996-11-13
DE3474117D1 (en) 1988-10-27
DE3327822A1 (en) 1985-02-14

Similar Documents

Publication Publication Date Title
DE2844464C2 (en) Method and device for compacting casting molds
EP0139119B1 (en) Method of and installation for compacting granular moulding materials, for example foundry mould sand
EP0170765B1 (en) Device for compacting foundry moulding material
EP0036434A1 (en) Method and device for compacting casting moulds
EP0263977B1 (en) Device for compacting moulding sand
DE3406466C2 (en)
EP0131723B1 (en) Device for compacting foundry mould material by means of pressurized gas
DE3914160C1 (en)
EP0203322B1 (en) Apparatus for compacting a foundry moulding material by means of compressed gas
DE2554414A1 (en) METHOD AND DEVICE FOR MANUFACTURING SAND CASTING MOLDS
DE4023180C1 (en) Press forming machine - has venting opening in hood enclosing pressure plate, filling frame and moulded, to prevent air ingress
DE910629C (en) Control of the movement of the shell of dies on hydraulically operated presses
DE3238712A1 (en) Apparatus for compacting dry sand in a mould, in particular in a casting mould
DE3717558C2 (en)
DD224248A5 (en) DEVICE FOR COMPRESSING FOUNDRY MOLDING MATERIAL
DE1949983A1 (en) Compression press, especially for plastic
EP0152573B1 (en) Apparatus for compacting foundry-moulding material using pressure gas
EP1155761A1 (en) Method and apparatus for the densification of moulding materials e.g. foundry sand
DE3240242C2 (en)
DE3432368C2 (en)
DE3613202C2 (en)
AT270389B (en) Deck press
DE19537204A1 (en) Moulding machine for sand moulds
DE3500488A1 (en) Apparatus for the production of casting moulds
DE3632925A1 (en) METHOD AND DEVICE FOR DAMPING THE PRESSURE TIP AT THE END OF THE FORM FILLING PHASE IN DIE CASTING MACHINES

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): AT CH DE FR GB IT LI

17P Request for examination filed

Effective date: 19851017

17Q First examination report despatched

Effective date: 19860624

R17C First examination report despatched (corrected)

Effective date: 19860824

R17C First examination report despatched (corrected)

Effective date: 19870127

ITCL It: translation for ep claims filed

Representative=s name: ORGANIZZAZIONE D'AGOSTINI

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT CH DE FR GB IT LI

REF Corresponds to:

Ref document number: 37305

Country of ref document: AT

Date of ref document: 19881015

Kind code of ref document: T

REF Corresponds to:

Ref document number: 3474117

Country of ref document: DE

Date of ref document: 19881027

ITF It: translation for a ep patent filed

Owner name: ORGANIZZAZIONE D'AGOSTINI

ET Fr: translation filed
GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)
PLBI Opposition filed

Free format text: ORIGINAL CODE: 0009260

26 Opposition filed

Opponent name: GEORG FISCHER AG

Effective date: 19890621

Opponent name: BMD BADISCHE MASCHINENFABRIK DURLACH GMBH

Effective date: 19890620

ITTA It: last paid annual fee
APAC Appeal dossier modified

Free format text: ORIGINAL CODE: EPIDOS NOAPO

PLAW Interlocutory decision in opposition

Free format text: ORIGINAL CODE: EPIDOS IDOP

PUAH Patent maintained in amended form

Free format text: ORIGINAL CODE: 0009272

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: PATENT MAINTAINED AS AMENDED

27A Patent maintained in amended form

Effective date: 19961113

AK Designated contracting states

Kind code of ref document: B2

Designated state(s): AT CH DE FR GB IT LI

REG Reference to a national code

Ref country code: CH

Ref legal event code: AEN

Free format text: AUFRECHTERHALTUNG DES PATENTES IN GEAENDERTER FORM

ITF It: translation for a ep patent filed

Owner name: ORGANIZZAZIONE D'AGOSTINI

ET3 Fr: translation filed ** decision concerning opposition
GBTA Gb: translation of amended ep patent filed (gb section 77(6)(b)/1977)
REG Reference to a national code

Ref country code: GB

Ref legal event code: IF02

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20030710

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20030721

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: AT

Payment date: 20030725

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: CH

Payment date: 20030728

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20030729

Year of fee payment: 20

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Free format text: LAPSE BECAUSE OF EXPIRATION OF PROTECTION

Effective date: 20040727

Ref country code: GB

Free format text: LAPSE BECAUSE OF EXPIRATION OF PROTECTION

Effective date: 20040727

Ref country code: CH

Free format text: LAPSE BECAUSE OF EXPIRATION OF PROTECTION

Effective date: 20040727

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: AT

Free format text: LAPSE BECAUSE OF EXPIRATION OF PROTECTION

Effective date: 20040728

REG Reference to a national code

Ref country code: GB

Ref legal event code: PE20

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

APAH Appeal reference modified

Free format text: ORIGINAL CODE: EPIDOSCREFNO

PLAB Opposition data, opponent's data or that of the opponent's representative modified

Free format text: ORIGINAL CODE: 0009299OPPO