EP0310802B1 - Process and apparatus for making foundry sand moulds and sand cores utilizing a binder - Google Patents

Process and apparatus for making foundry sand moulds and sand cores utilizing a binder Download PDF

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Publication number
EP0310802B1
EP0310802B1 EP88113769A EP88113769A EP0310802B1 EP 0310802 B1 EP0310802 B1 EP 0310802B1 EP 88113769 A EP88113769 A EP 88113769A EP 88113769 A EP88113769 A EP 88113769A EP 0310802 B1 EP0310802 B1 EP 0310802B1
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EP
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Prior art keywords
pressure container
pressure
reagent
container
supplied
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EP88113769A
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German (de)
French (fr)
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EP0310802A1 (en
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Franz Gähler
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/12—Treating moulds or cores, e.g. drying, hardening
    • B22C9/123—Gas-hardening
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S261/00—Gas and liquid contact apparatus
    • Y10S261/65—Vaporizers

Definitions

  • the invention relates to a method and a device for producing molds or cores from a foundry sand mixed with a binder and introduced into a mold box or core box, which for curing a pressure container connected to the mold or core box has a vacuum therein evaporated reagent is supplied.
  • a method and a device for curing an organic binder in a mold or core box are known, in which / by means of a connected pump the pressure within of the mold or core box is reduced.
  • a valve to a reagent container is opened, whereby an, for example liquid amine therein is exposed to the low pressure of the mold or core box for evaporation and at the same time a carrier gas is supplied to the reagent container.
  • the amine evaporated thereby and mixed with the carrier gas is essentially sucked in by the negative pressure present in the mold or core box for curing the material contained therein.
  • a vacuum is generated to transfer the vaporized amine in the mold or core box, the amine thus evaporated being fed to the mold or core box without an appropriate dosage.
  • the negative pressure is released, which results in a reduced evaporation of the reagent.
  • a method and a device are also known, in which a liquid hardener is metered from a storage container via a nozzle valve to an evaporator and is evaporated therein.
  • the evaporated, gaseous hardener is fed to the mold or core box from a carrier gas air stream supplied to the evaporator.
  • the invention has for its object to improve a method and a device for curing molds or cores in such a way that, using appropriate amines or other reagents, an optimal evaporation and supply of the vaporized reagents to the mold or core box and thereby a uniform curing of the molds or cores and a significantly reduced odor nuisance can be achieved.
  • the object is achieved according to the method according to the invention in that the required vacuum and an elevated temperature are first generated in the pressure vessel and then the reagent for evaporation is fed to the pressure vessel, and then the pressure vessel under pressure with a gaseous gas under pressure Medium is applied and thereby the vaporized reagent is fed to the mold or core box.
  • the device according to the invention for carrying out the method comprises a pressure vessel operatively connected to a pressure source and a vacuum pump, from which a reagent vaporized therein can be fed to a mold or core box connected to the pressure vessel, and is characterized in that the pressure vessel is designed to be heatable and that Reagent to be evaporated can be fed to the pressure container from a storage container via a metering pump.
  • a control valve is assigned to each of the individual organs connected to the pressure vessel (mold or core box, heating element, pressure source, vacuum pump and metering pump), the individual control valve being precisely controllable by a control device connected to a processor.
  • 1 designates a housing-like mold or core box, in which a foundry mold or a foundry core is produced by curing the foundry sand introduced therein and mixed with a binder.
  • a reagent e.g. used in the form of a liquid amine, of which a certain amount is provided in a storage container 2.
  • the storage container 2 expediently holds such an amount that it covers a daily requirement, the supply being expediently monitored by a level measuring device 3.
  • the level measuring device 3 is shown schematically as a standpipe, but other level measuring devices can also be used.
  • the storage container 2 has a feed line 4 which can be closed and opened by a 2/2 valve 5 (with two switching positions and two connections). Through the feed line 4, the reagent can be fed from a reserve container 6 to the storage container 2.
  • the pressure vessel 7 has a number of line connections 8-11. At the connection 8, a compressed air or compressed gas supply line 12 ends, at the beginning of which a pressure source 15 is connected.
  • An oil separator 16, a pressure control valve 17 and a 2/2-valve 18 are arranged one after the other in the feed line 12. With the pressure control valve 17, the inlet pressure to the pressure vessel 7 is set or varied.
  • the pressure control valve 17 is controlled by a central programmable processor 20.
  • the processor 20 is connected to the pressure control valve 17 via a control line 21 shown in dashed lines. Further control lines 21 shown in dashed lines in the figure connect the processor 20 to the corresponding devices.
  • the 2/2 valve 18 is also connected to the processor 20 via such a control line 21.
  • a connecting line 22 is connected to the line connection 9 and connects to the molded or core box 1 via a 2/2 valve 23 connected is.
  • the connecting line 22 can be a rigid or flexible line, which can also be heated.
  • the valve 23 is connected to a control line 21 with a control device 25, which in turn is connected to the processor 20 via a control line 21.
  • a 2/2-way valve 29 is also arranged in the pressure line 26 and is connected to the control device 25 via a control line 21.
  • the metering pump 27 which can be a membrane pump, for example, the volume of reagents required in each case is conveyed into the pressure line 26 into the pressure vessel 7.
  • the metering pump 27 has a suction line 30 connected to the storage container 2, through which the metering pump 27 draws in the reagent.
  • a suction line 31 of a vacuum pump 33 is connected to the line connection 11 and is driven by an electric motor 34.
  • the motor 34 is connected to the processor 20 via a control line 21. It is also possible to provide a 2/2 valve 31 '(shown in dashed lines) controlled by the processor 20 in the suction line 31, as in the pressure line 26 of the metering pump 27.
  • a pressure measuring device 35 is connected to the pressure vessel 7 and supplies the processor 20 with control signals via a control line 21.
  • the pressure vessel 7 has the task of heating both the compressed air supplied by the pressure source 15 or the compressed gas and to evaporate the volume of reagents supplied by the metering pump 27.
  • a rod-shaped heating element 36 is installed in the interior of the pressure vessel 7, the current-carrying lines 37 of which are connected to the control device 25 for controlling the supplied heating energy.
  • the pressure vessel 7 can be designed in various ways. Heat exchange tubes 38, 39 are arranged in the interior of the pressure vessel 7, of which, however, only one line is shown.
  • the entire interior of the pressure vessel 7 can also be filled with a matrix, for example made of aluminum, for the purpose of heat storage.
  • the cylindrical pressure vessel 7 is at the operating temperature and the molded or core box 1 filled with sand and binder is connected to the connecting line 22.
  • the supply line 12 of the pressure source 15 and the pressure line 26 of the metering pump 27 and the connecting line 22 closed while the vacuum pump 33 is switched on and generates a lower pressure in the pressure vessel 7.
  • This pressure can be monitored and regulated by the pressure measuring device 35.
  • the metering pump 27 delivers a predetermined amount of reagents into the pressure container 7 after opening the valve 29.
  • the reagent evaporates very quickly. Then the valve 18 of the pressure line 12 is opened and compressed air or a compressed gas flows into the pressure vessel 7, the negative pressure of which is changed to an excess pressure in a short time. After the valve 23 is opened, the evaporated reagent is conveyed into the mold or core box 1 by the compressed air or by the pressurized gas, as a result of which the mold or core is cured. After removing the form or core box 1 the mold or core inside must be removed and then refilled with sand and binding agent. During this time, the process is repeated, ie the vacuum pump 33 generates the desired negative pressure in the pressure container 7.
  • the advantage of the described device is that by generating a negative pressure in the cylindrical pressure vessel 7, the boiling point of the amine being conveyed can be significantly reduced, so that amines which have not previously been usable, e.g. the amine TEA triethylamine with a boiling point of 88 ° C can be used. However, this amine is evaporated with less energy and chemical costs than when an amine with a lower boiling temperature, e.g. the amine DMEA dimethylethylamine with 36 ° C boiling point is used in a known plant without vacuum generation.

Abstract

The mould or core housing (1) filled with foundry sand and binder is cured by means of a reagent which is vaporised. The reagent is introduced into the housing (1) from a cylindrical container (7) using a propellant flow delivered from a pressure source (15). The reagent is conveyed by a metering pump (27) into the container (7), in which a subatmospheric pressure produced by a vacuum pump (33) prevails. Due to the subatmospheric pressure, the reagent vaporises more rapidly than at atmospheric pressure. It is thereby possible to use reagents with a high boiling point, as a result of which the curing of the moulds and cores can be effected more economically and with less smell. <IMAGE>

Description

Die Erfindung bezieht sich auf ein Verfahren und eine Einrichtung zur Herstellung von Formen oder Kernen aus einem mit einem Bindemittel vermischten und in einen Formkasten oder Kernkasten eingebrachten Giessereisand, welchem zur Aushärtung von einem mit dem Form- oder Kernkasten in Verbindung stehenden Druckbehälter ein darin unter Unterdruck verdampftes Reagenz zugeführt wird.The invention relates to a method and a device for producing molds or cores from a foundry sand mixed with a binder and introduced into a mold box or core box, which for curing a pressure container connected to the mold or core box has a vacuum therein evaporated reagent is supplied.

Aus der FR-A 2 376 696, von welcher die Oberbegriffe der Ansprüche 1 und 6 ausgehen, sind ein Verfahren und eine Einrichtung zum Aushärten eines organischen Bindemittels in einem Form- oder Kernkasten bekannt, bei welchem/welcher mittels einer angeschlossenen Pumpe der Druck innerhalb des Form- oder Kernkastens verringert wird. Bei Erreichung eines vorgegebenen Unterdruck-Wertes innerhalb des Form- oder Kernkastens wird ein Ventil zu einem Reagenzbehälter geöffnet, wodurch ein darin befindliches, beipielsweise flüssiges Amin dem niederen Druck des Form- oder Kernkastens zur Verdampfung ausgesetzt und gleichzeitig dem Reagenzbehälter ein Trägergas zugeführt wird. Das dadurch verdampfte und mit dem Trägergas vermischte Amin wird im wesentlichen von dem im Form- oder Kernkasten vorliegenden Unterdruck zur Aushärtung des darin befindlichen Material angesaugt.From FR-A 2 376 696, from which the preambles of claims 1 and 6 are based, a method and a device for curing an organic binder in a mold or core box are known, in which / by means of a connected pump the pressure within of the mold or core box is reduced. When a predetermined vacuum value within the mold or core box is reached, a valve to a reagent container is opened, whereby an, for example liquid amine therein is exposed to the low pressure of the mold or core box for evaporation and at the same time a carrier gas is supplied to the reagent container. The amine evaporated thereby and mixed with the carrier gas is essentially sucked in by the negative pressure present in the mold or core box for curing the material contained therein.

Bei dieser Einrichtung wird zur Überführung des verdampften Amins in dem Form- oder Kernkasten ein Unterdruck erzeugt, wobei das derart verdampfte Amin dabei ohne eine entsprechende Dosierung dem Form- oder Kernkasten zugeführt wird. Durch die gleichzeitige Zuführung des Trägergases in den Reagenzbehälter wird der Unterdruck aufgehoben, was eine verminderte Verdampfung des Reagenzes zur Folge hat.In this device, a vacuum is generated to transfer the vaporized amine in the mold or core box, the amine thus evaporated being fed to the mold or core box without an appropriate dosage. By simultaneously feeding the carrier gas into the reagent container, the negative pressure is released, which results in a reduced evaporation of the reagent.

Aus der DE-A 2 526 875 sind ein Verfahren und eine Einrichtung zum Aushärten von Sandformen und Sandkernen durch ein Katalysatorgas bekannt, bei welchem/welcher der Form- oder Kernkasten während des gesamten Aushärtevorganges ununterbrochen der Wirkung einer Unterdruckquelle ausgesetzt ist, wobei unmittelbar nach der Zufuhr des Katalysatorgases dieses wieder zu einem das Katalysatorgas aufnehmenden Vorratsbehälter abgesaugt wird.From DE-A 2 526 875 a method and a device for hardening sand molds and sand cores by means of a catalyst gas are known, in which the mold or core box is continuously exposed to the effect of a vacuum source during the entire hardening process, immediately after the Supply of the catalyst gas this is sucked off again to a storage container receiving the catalyst gas.

Aus der DE-A 3 546 000 sind weiterhin ein Verfahren und eine Vorrichtung bekannt, bei welchem/welcher ein flüssiger Härter aus einem Vorratsbehälter über ein Düsenventil dosiert einem Verdampfer zugeführt und darin verdampft wird. Von einem dem Verdampfer zugeführten Trägergas-Luftstrom wird der verdampfte, gasförmige Härter dem Form- oder Kernkasten zugeführt.From DE-A 3 546 000 a method and a device are also known, in which a liquid hardener is metered from a storage container via a nozzle valve to an evaporator and is evaporated therein. The evaporated, gaseous hardener is fed to the mold or core box from a carrier gas air stream supplied to the evaporator.

Der Erfindung liegt die Aufgabe zugrunde, ein Verfahren sowie eine Einrichtung zum Aushärten von Formen oder Kernen dahingehend zu verbessern, dass unter Verwendung entsprechender Amine oder anderer Reagenzien eine optimale Verdampfung sowie Zuführung der verdampften Reagenzien zum Form- oder Kernkasten und dadurch eine gleichmässige Aushärtung der Formen oder Kerne gewährleistet sowie eine wesentlich verringerte Geruchsbelästigung erreicht werden.The invention has for its object to improve a method and a device for curing molds or cores in such a way that, using appropriate amines or other reagents, an optimal evaporation and supply of the vaporized reagents to the mold or core box and thereby a uniform curing of the molds or cores and a significantly reduced odor nuisance can be achieved.

Die Aufgabe wird nach dem erfindungsgemässen Verfahren dadurch gelöst, dass in dem Druckbehälter zuerst der erforderliche Unterdruck sowie eine erhöhte Temperatur erzeugt werden und danach das Reagenz zur Verdampfung dem Druckbehälter zugeführt wird, und dass anschliessend der unter Unterdruck stehende Druckbehälter mit einem unter Überdruck stehenden, gasförmigen Medium beaufschlagt und dadurch das verdampfte Reagenz dem Form- oder Kernkasten zugeführt wird.The object is achieved according to the method according to the invention in that the required vacuum and an elevated temperature are first generated in the pressure vessel and then the reagent for evaporation is fed to the pressure vessel, and then the pressure vessel under pressure with a gaseous gas under pressure Medium is applied and thereby the vaporized reagent is fed to the mold or core box.

Durch die exakte Trennung des Verdampfungsvorganges von dem Mischvorgang mit dem als Trägergas dienenden Medium wird eine optimale Verdampfung und Zuführung des Gemisches zu dem Form- oder Kernkasten gewährleistet und somit eine optimale Aushärtung der Elemente erreicht.Due to the exact separation of the evaporation process from the mixing process with the medium serving as carrier gas, an optimal evaporation and supply of the mixture to the mold or core box is guaranteed and thus an optimal curing of the elements is achieved.

Die erfindungsgemässe Einrichtung zur Durchführung des Verfahrens umfasst einen mit einer Druckquelle und einer Vakuumpumpe wirkverbundenen Druckbehälter, von welchem ein darin verdampftes Reagenz einem mit dem Druckbehälter in Verbindung stehenden Form- oder Kernkasten zuführbar ist, und ist dadurch gekennzeichnet, dass der Druckbehälter beheizbar ausgebildet und das zu verdampfende Reagenz über eine Dosierpumpe von einem Vorrratsbehälter dem Druckbehälter zuführbar ist.The device according to the invention for carrying out the method comprises a pressure vessel operatively connected to a pressure source and a vacuum pump, from which a reagent vaporized therein can be fed to a mold or core box connected to the pressure vessel, and is characterized in that the pressure vessel is designed to be heatable and that Reagent to be evaporated can be fed to the pressure container from a storage container via a metering pump.

Den einzelnen, mit dem Druckbehälter in Verbindung stehenden Organen (Form- oder Kernkasten, Heizelement, Druckquelle, Vakuumpumpe und Dosierpumpe) ist je ein Regelventil zugeordnet, wobei das einzelne Regelventil von einem mit einem Prozessor in Verbindung stehenden Regelgerät exakt steuerbar ist.A control valve is assigned to each of the individual organs connected to the pressure vessel (mold or core box, heating element, pressure source, vacuum pump and metering pump), the individual control valve being precisely controllable by a control device connected to a processor.

Weitere Merkmale der Erfindung ergeben sich aus der folgenden Beschreibung in Verbindung mit der Zeichnung und den Patentansprüchen.Further features of the invention will become apparent from the following description in conjunction with the drawing and the claims.

Die Erfindung wird nachstehend anhand der Zeichnung beschrieben, wobei die Zeichnung eine schematisch dargestellte Einrichtung zum Aushärten von Formen oder Kernen in einem Form- oder Kernkasten zeigt.The invention is described below with reference to the drawing, the drawing showing a schematically illustrated device for curing molds or cores in a mold or core box.

In der Figur ist mit 1 ein gehäuseartig ausgebildeter Form- oder Kernkasten bezeichnet, in welchem eine Giessereiform oder ein Giessereikern durch Aushärten des darin eingebrachten, mit einem Bindemittel versetzten Giesserisand hergestellt wird. Hierzu wird ein Reagenz, z.B. in Form eines flüssigen Amines verwendet, von dem eine bestimmte Menge in einem Vorratsbehälter 2 bereit gestellt wird. Zweckmässig fasst der Vorratsbehälter 2 eine solche Menge, dass damit ein Tagesbedarf gedeckt wird, wobei der Vorrat zweckmässig durch ein Niveaumessgerät 3 überwacht wird. Das Niveaumessgerät 3 ist schematisch als Standrohr dargestellt, jedoch können auch andere Niveaumessgeräte eingesetzt werden. Der Vorratsbehälter 2 weist eine Zuleitung 4 auf, welche durch ein 2/2-Ventil 5 (mit zwei Schaltstellungen und zwei Anschlüssen) geschlossen und geöffnet werden kann. Durch die Zuleitung 4 kann das Reagenz aus einem Reservebehälter 6 dem Vorratsbehälter 2 zugeführt werden.In the figure, 1 designates a housing-like mold or core box, in which a foundry mold or a foundry core is produced by curing the foundry sand introduced therein and mixed with a binder. A reagent, e.g. used in the form of a liquid amine, of which a certain amount is provided in a storage container 2. The storage container 2 expediently holds such an amount that it covers a daily requirement, the supply being expediently monitored by a level measuring device 3. The level measuring device 3 is shown schematically as a standpipe, but other level measuring devices can also be used. The storage container 2 has a feed line 4 which can be closed and opened by a 2/2 valve 5 (with two switching positions and two connections). Through the feed line 4, the reagent can be fed from a reserve container 6 to the storage container 2.

Einen wesentlicher Teil der in der Figur dargestellten Anlage stellt ein stehender, zylinderförmiger Druckbehälter 7 dar. Der Druckbehälter 7 weist eine Anzahl Leitungsanschlüsse 8 - 11 auf. An dem Anschluss 8 endet eine Druckluft- oder Druckgaszuleitung 12, an deren Anfang eine Druckquelle 15 angeschlossen ist. In der Zuleitung 12 sind nacheinander ein Oelabscheider 16, ein Druckregelventil 17 und ein 2/2-Ventil 18 angeordnet. Mit dem Druckregelventil 17 wird der Zulaufdruck zum Druckbehälter 7 eingestellt oder auch variiert. Die Steuerung des Druckregelventils 17 erfolgt durch einen zentralen programmierbaren Prozessor 20. Der Prozessor 20 ist mit dem Druckregelventil 17 über eine, gestrichelt dargestellte Steuerleitung 21, verbunden. Weitere in der Figur gestrichelt dargestellte Steuerleitungen 21 verbinden den Prozessor 20 mit den entsprechenden Geräten. Auch das 2/2-Ventil 18 ist über eine solche Steuerleitung 21 mit dem Prozessor 20 verbunden.An essential part of the system shown in the figure is a standing, cylindrical pressure vessel 7. The pressure vessel 7 has a number of line connections 8-11. At the connection 8, a compressed air or compressed gas supply line 12 ends, at the beginning of which a pressure source 15 is connected. An oil separator 16, a pressure control valve 17 and a 2/2-valve 18 are arranged one after the other in the feed line 12. With the pressure control valve 17, the inlet pressure to the pressure vessel 7 is set or varied. The pressure control valve 17 is controlled by a central programmable processor 20. The processor 20 is connected to the pressure control valve 17 via a control line 21 shown in dashed lines. Further control lines 21 shown in dashed lines in the figure connect the processor 20 to the corresponding devices. The 2/2 valve 18 is also connected to the processor 20 via such a control line 21.

An dem Leitungsanschluss 9 ist eine Verbindungsleitung 22 angeschlossen, welche über ein 2/2-Ventil 23 mit dem Form- oder Kernkasten 1 verbunden ist. Die Verbindungsleitung 22 kann eine starre oder flexible Leitung sein, die auch beheizt sein kann. Das Ventil 23 ist mit einer Steuerleitung 21 mit einem Reglegerät 25 verbunden, das seinerseits mit dem Prozessor 20 über eine Steuerleitung 21 verbunden ist.A connecting line 22 is connected to the line connection 9 and connects to the molded or core box 1 via a 2/2 valve 23 connected is. The connecting line 22 can be a rigid or flexible line, which can also be heated. The valve 23 is connected to a control line 21 with a control device 25, which in turn is connected to the processor 20 via a control line 21.

An dem Leitungsanschluss 10 mündet eine Druckleitung 26 einer Dosierpumpe 27, die durch einen Elektromotor angetrieben ist, welcher über eine Steuerleitung 21 mit dem Regelgerät 25 verbunden ist. In der Druckleitung 26 ist zudem ein 2/2-Ventil 29 angeordnet, welches über eine Steurleitung 21 mit dem Regelgerät 25 verbunden ist.A pressure line 26 of a metering pump 27, which is driven by an electric motor and which is connected to the control device 25 via a control line 21, opens at the line connection 10. A 2/2-way valve 29 is also arranged in the pressure line 26 and is connected to the control device 25 via a control line 21.

Mit der Dosierpumpe 27, die beispielsweise eine Membranpumpe sein kann, wird das jeweils benötigte Volumen an Reagenzien in die Druckleitung 26 in den Druckbehälter 7 gefördert. Die Dosierpumpe 27 weist eine mit dem Vorratsbehälter 2 verbundene Saugleitung 30 auf, durch welche die Dosierpumpe 27 das Reagenz ansaugt.With the metering pump 27, which can be a membrane pump, for example, the volume of reagents required in each case is conveyed into the pressure line 26 into the pressure vessel 7. The metering pump 27 has a suction line 30 connected to the storage container 2, through which the metering pump 27 draws in the reagent.

An dem Leitungsanschluss 11 ist eine Saugleitung 31 einer Vakuumpumpe 33 angeschlossen, welche durch einen Elektromotor 34 angetrieben wird. Der Motor 34 ist über eine Steuerleitung 21 mit dem Prozessor 20 verbunden. Es ist auch möglich, in der Saugleitung 31 - wie in der Druckleitung 26 der Dosierpumpe 27 - ein vom Prozessor 20 gesteuertes 2/2-Ventil 31' (gestrichelt dargestellt) vorzusehen.A suction line 31 of a vacuum pump 33 is connected to the line connection 11 and is driven by an electric motor 34. The motor 34 is connected to the processor 20 via a control line 21. It is also possible to provide a 2/2 valve 31 '(shown in dashed lines) controlled by the processor 20 in the suction line 31, as in the pressure line 26 of the metering pump 27.

Am Druckbehälter 7 ist ein Druckmessgerät 35 angeschlossen, das über eine Steuerleitung 21 dem Prozessor 20 Steuersignale liefert.A pressure measuring device 35 is connected to the pressure vessel 7 and supplies the processor 20 with control signals via a control line 21.

Der Druckbehälter 7 hat die Aufgabe, sowohl die von der Druckquelle 15 gelieferte Druckluft oder das Druckgas zu erwärmen als auch das durch die Dosierpumpe 27 gelieferte Volumen an Reagenzien zu verdampfen. Hierzu ist im Innern des Druckbehälters 7 ein stabförmiges Heizelement 36 eingebaut, dessen stromführende Leitungen 37 mit dem Regelgerät 25 zur Steuerung der zugeführten Heizenergie verbunden sind. Der Druckbehälter 7 kann in verschiedener Weise ausgebildet sein. Im Innenraum des Druckbehälters 7 sind Wärmeaustauschrohre 38, 39 angeordnet, von denen jedoch nur eine Leitung dargestellt ist. Der gesamte Innenraum des Druckbehälters 7 kann zudem mit einer Matrix, z.B. aus Aluminium, zwecks Wärmespeicherung ausgefüllt sein.The pressure vessel 7 has the task of heating both the compressed air supplied by the pressure source 15 or the compressed gas and to evaporate the volume of reagents supplied by the metering pump 27. For this purpose, a rod-shaped heating element 36 is installed in the interior of the pressure vessel 7, the current-carrying lines 37 of which are connected to the control device 25 for controlling the supplied heating energy. The pressure vessel 7 can be designed in various ways. Heat exchange tubes 38, 39 are arranged in the interior of the pressure vessel 7, of which, however, only one line is shown. The entire interior of the pressure vessel 7 can also be filled with a matrix, for example made of aluminum, for the purpose of heat storage.

Der Betrieb der in der Figur dargestellten Anlage oder Einrichtung läuft wie folgt ab:
Es wird angenommen, dass der zylinderförmige Druckbehälter 7 sich auf Betriebstemperatur befindet und der mit Sand und Bindemittel gefüllte Form- oder Kernkasten 1 mit der Verbindungsleitung 22 verbunden ist. Während der Vorbereitung für das Ansetzen des Form- oder Kernkastens 1 an die Leitung 22, d.h. für das Füllen des Form- oder Kernkastens 1 mit Sand und Binder, sind die Zuleitung 12 der Druckquelle 15 und die Druckleitung 26 der Dosierpumpe 27 sowie die Verbindungsleitung 22 geschlossen, während die Vakuumpumpe 33 eingeschaltet ist und im Druckbehälter 7 einen kleineren Druck erzeugt. Dieser Druck kann durch das Druckmessgerät 35 überwacht und geregelt werden. Nach Erreichen des gewünschten Unterdruckes wird von der Dosierpumpe 27 nach Oeffnen des Ventils 29 eine vorbestimmte Menge Reagenzien in den Druckbehälter 7 gefördert. Durch den Unterdruck einerseits und die vorhandene erhöhte Temperatur im Druckbehälter 7, z.B. 80 - 125 ° C erfolgt eine sehr rasche Verdampfung des Reagenzes. Dann wird das Ventil 18 der Druckleitung 12 geöffnet und Druckluft oder ein Druckgas strömt in den Druckbehälter 7, dessen Unterdruck in kurzer Zeit in einen Ueberdruck geändert wird. Nachdem das Ventil 23 geöffnet ist, wird das verdampfte Reagenz durch die Druckluft bzw. durch das Druckgas in den Form- oder Kernkasten 1 gefördert, wodurch die Aushärtung der Form oder des Kernes erfolgt. Nach Entfernen des Form- oder Kernkastens 1 muss die darin befindliche Form oder der Kern entfernt und anschliessend wieder neu mit Sand und Bindemittel gefüllt werden. Während dieser Zeit wiederholt sich der Vorgang, d.h. die Vakuumpumpe 33 erzeugt den gewünschten Unterdruck im Druckbehälter 7. Sobald dieser Unterdruck erreicht ist, wird das Reagenz zugeführt und fast gleichzeitig die Druckluft oder das Druckgas in den Druckbehälter 7 eingeleitet. In dieser Zeit ist ein neue Form- oder Kernkasten 1 an die Leitung 22 angeschlossen worden, worauf nach Oeffnen des Ventils 23 in der Leitung 22 ein neuer Aushärtungsvorgang abläuft.The operation of the system or device shown in the figure proceeds as follows:
It is assumed that the cylindrical pressure vessel 7 is at the operating temperature and the molded or core box 1 filled with sand and binder is connected to the connecting line 22. During the preparation for attaching the mold or core box 1 to the line 22, ie for filling the mold or core box 1 with sand and binder, the supply line 12 of the pressure source 15 and the pressure line 26 of the metering pump 27 and the connecting line 22 closed while the vacuum pump 33 is switched on and generates a lower pressure in the pressure vessel 7. This pressure can be monitored and regulated by the pressure measuring device 35. After the desired negative pressure has been reached, the metering pump 27 delivers a predetermined amount of reagents into the pressure container 7 after opening the valve 29. Because of the negative pressure on the one hand and the increased temperature in the pressure vessel 7, for example 80-125 ° C., the reagent evaporates very quickly. Then the valve 18 of the pressure line 12 is opened and compressed air or a compressed gas flows into the pressure vessel 7, the negative pressure of which is changed to an excess pressure in a short time. After the valve 23 is opened, the evaporated reagent is conveyed into the mold or core box 1 by the compressed air or by the pressurized gas, as a result of which the mold or core is cured. After removing the form or core box 1 the mold or core inside must be removed and then refilled with sand and binding agent. During this time, the process is repeated, ie the vacuum pump 33 generates the desired negative pressure in the pressure container 7. As soon as this negative pressure is reached, the reagent is supplied and the compressed air or the compressed gas is introduced into the pressure container 7 almost simultaneously. During this time, a new mold or core box 1 has been connected to line 22, whereupon a new curing process takes place after opening valve 23 in line 22.

Der Vorteil der beschriebenen Einrichtung besteht darin, dass durch die Erzeugung eines Unterdruckes im zylinderförmigen Druckbehälter 7 der Siedepunkt des geförderten Amines wesentlich herabgesetzt werden kann, sodass bisher nicht verwendbare Amine, z.B. das Amin TEA Triäthylamin mit einem Siedepunkt von 88 °C verwendbar ist. Die Verdampfung dieses Amines erfolgt jedoch mit geringerem Energieaufwand und geringeren Chemikalienkosten, als wenn ein Amin mit kleinerer Siedetemperatur, z.B. das Amin DMEA Dimethyläthylamin mit 36 °C Siedepunkt in einer bekannten Anlage ohne Vakuumerzeugung eingesetzt wird.The advantage of the described device is that by generating a negative pressure in the cylindrical pressure vessel 7, the boiling point of the amine being conveyed can be significantly reduced, so that amines which have not previously been usable, e.g. the amine TEA triethylamine with a boiling point of 88 ° C can be used. However, this amine is evaporated with less energy and chemical costs than when an amine with a lower boiling temperature, e.g. the amine DMEA dimethylethylamine with 36 ° C boiling point is used in a known plant without vacuum generation.

Claims (9)

  1. Method for the manufacture of moulds and/or cores from moulding sand mixed with a binding agent and introduced into a moulding box or core box, to which moulding sand, for hardening, there is supplied from a pressure container (7) connected to the moulding or core box (1) a reagent evaporated in the pressure container (7) under vacuum, characterized in that in the pressure container (7) first of all the necessary vacuum and also an increased temperature are generated and thereafter the reagent for evaporation is supplied to the pressure container (7), and that subsequently the pressure container (7) under vacuum is loaded with a gaseous medium under excess pressure and in this way the evaporated reagent is supplied to the moulding or core box (1).
  2. Method according to claim 1, characterized in that to the pressure container (7) there is supplied from an associated supply container (2) the reagent as predetermined dosed quantity to the pressure container (7) and in the pressure container (7), with the maintenance of the vacuum present, is heated to a temperature of 70°C to 130°C.
  3. Method according to one of claims 1 and 2, characterized in that in a successive manufacture of moulds and cores in the pressure container (7) in each case a vacuum is generated before the introduction of the reagent quantity.
  4. Method according to claim 1, characterized in that a predetermined dosed quantity of reagent is supplied to the pressure container (7).
  5. Method according to one of claims 1 to 3, characterized in that the gaseous medium supplied under appropriate excess pressure is heated in the pressure container (7).
  6. Device for carrying out the method according to claim 1, consisting of a pressure container (7) operatively connected to a pressure source (15) and a vacuum pump (33), from which pressure container (7) an evaporated reagent can be supplied to a moulding or core box (1) connected to the pressure container, characterized in that the pressure container (7) is constructed so that it can be heated and the reagent to be evaporated can be supplied via a dosing pump (27) from a supply container (2) to the pressure container (7).
  7. Device according to claim 6, characterized in that a heating element (36) is arranged in the pressure container (7), the heating element being operatively connected to a controllable regulating apparatus (25).
  8. Device according to claim 6, characterized in that in the connection lines (22;12;31;26) leading from the pressure container (7) to the moulding or core box (1), to the pressure source (15), to the vacuum pump (33) as well as to the reagent supply container (2) in each case there is arranged a valve (23;17,18;31';29) in operative connection with the regulating apparatus (25) and/or with a processor (20).
  9. Device according to claim 6, characterized in that the pressure container (7) is constructed as a stationary cylinder body, the structural length of which corresponds to a multiple of its diameter, and that the connection line (26) leading to the supply container (2) is attached in the upper region of the pressure container (7).
EP88113769A 1987-10-02 1988-08-24 Process and apparatus for making foundry sand moulds and sand cores utilizing a binder Expired - Lifetime EP0310802B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT88113769T ATE76340T1 (en) 1987-10-02 1988-08-24 METHOD AND DEVICE FOR THE MANUFACTURE OF FOUNDRY MOLDS AND CORE FROM SAND WITH A BINDING AGENT.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH3865/87A CH674480A5 (en) 1987-10-02 1987-10-02
CH3865/87 1987-10-02

Publications (2)

Publication Number Publication Date
EP0310802A1 EP0310802A1 (en) 1989-04-12
EP0310802B1 true EP0310802B1 (en) 1992-05-20

Family

ID=4265143

Family Applications (1)

Application Number Title Priority Date Filing Date
EP88113769A Expired - Lifetime EP0310802B1 (en) 1987-10-02 1988-08-24 Process and apparatus for making foundry sand moulds and sand cores utilizing a binder

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US (1) US5005630A (en)
EP (1) EP0310802B1 (en)
AT (1) ATE76340T1 (en)
CH (1) CH674480A5 (en)
DE (1) DE3871315D1 (en)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH679913A5 (en) * 1989-07-14 1992-05-15 Werner Lueber
US5135043A (en) * 1990-06-25 1992-08-04 Omco Usa, Inc. Apparatus and method for gas curing foundry cores and molds
US5252134A (en) * 1991-05-31 1993-10-12 Stauffer Craig M Integrated delivery system for chemical vapor from non-gaseous sources for semiconductor processing
DE4120928A1 (en) * 1991-06-25 1993-01-07 Unterderweide Gmbh METHOD FOR CURING SAND MOLDED BODIES, IN PARTICULAR FOR FOUNDRIES
DE4318153C1 (en) * 1993-06-01 1994-05-19 Hermann Blachowski Producing sand cores - with gas for hardening the binder fed to moulding box as liq. and vaporised inside box
US5971056A (en) * 1997-05-27 1999-10-26 Luger GmbH Device for hardening foundry cores and use thereof
GB2333984A (en) * 1998-02-10 1999-08-11 Dean Anthony Jones Heater for curing sand cores
DE102011050264B4 (en) * 2011-05-11 2015-11-19 Stephanus Bigos Apparatus for fumigating cast cores

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Publication number Priority date Publication date Assignee Title
US4051886A (en) * 1973-08-27 1977-10-04 Liquid Carbonic Canada Ltd. Saturated liquid/vapor generating and dispensing
US4064926A (en) * 1975-06-16 1977-12-27 Acme-Cleveland Corporation Sand molding apparatus with means for recirculating catalyst
PL191229A1 (en) * 1976-07-15 1978-01-16 Odlewniczych Fab Mas METHOD OF CURING QUICK-CURING MOLDING MATERIALS AND CURING QUICK-CURING MOLDING MASSES
FR2376696A1 (en) * 1977-01-07 1978-08-04 Stone Wallwork Ltd Vaporiser for hardening organic binder in foundry sand mixt. - using liq. amine catalyst which is evaporated by vacuum in the core-box
US4362204A (en) * 1980-03-17 1982-12-07 The Mead Corporation Method and apparatus for curing a foundry core
US4312397A (en) * 1980-04-14 1982-01-26 Dependable-Fordath, Inc. Process for forming shell molds
US4483384A (en) * 1980-06-02 1984-11-20 Michel Horst Werner Apparatus for hardening mold parts made of sand for making metal castings
US4540531A (en) * 1984-05-04 1985-09-10 Ashland Oil, Inc. Vapor generator and its use in generating vapors in a pressurized gas
DE3546000A1 (en) * 1985-12-24 1987-06-25 Meppener Eisenhuette Gmbh Process and apparatus for the production of shaped articles (mouldings)

Also Published As

Publication number Publication date
ATE76340T1 (en) 1992-06-15
CH674480A5 (en) 1990-06-15
US5005630A (en) 1991-04-09
EP0310802A1 (en) 1989-04-12
DE3871315D1 (en) 1992-06-25

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