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EP0670207B1 - Device for making cylindrical tubular products - Google Patents

Device for making cylindrical tubular products Download PDF

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Publication number
EP0670207B1
EP0670207B1 EP95102778A EP95102778A EP0670207B1 EP 0670207 B1 EP0670207 B1 EP 0670207B1 EP 95102778 A EP95102778 A EP 95102778A EP 95102778 A EP95102778 A EP 95102778A EP 0670207 B1 EP0670207 B1 EP 0670207B1
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EP
European Patent Office
Prior art keywords
steel
molding
set forth
mandrel
ring
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Expired - Lifetime
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EP95102778A
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German (de)
French (fr)
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EP0670207A1 (en
Inventor
Klaus Dipl.-Ing. Strobel
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B21/00—Methods or machines specially adapted for the production of tubular articles
    • B28B21/02—Methods or machines specially adapted for the production of tubular articles by casting into moulds
    • B28B21/10—Methods or machines specially adapted for the production of tubular articles by casting into moulds using compacting means
    • B28B21/18—Methods or machines specially adapted for the production of tubular articles by casting into moulds using compacting means using expansible or retractable mould or core elements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B21/00—Methods or machines specially adapted for the production of tubular articles
    • B28B21/02—Methods or machines specially adapted for the production of tubular articles by casting into moulds
    • B28B21/10—Methods or machines specially adapted for the production of tubular articles by casting into moulds using compacting means
    • B28B21/36—Methods or machines specially adapted for the production of tubular articles by casting into moulds using compacting means applying fluid pressure or vacuum to the material

Definitions

  • the invention relates to a device for Production of at least approximately hollow cylindrical Products, especially thin-walled pipes, made of ceramic, finely divided materials through isostatic Pressing, in which within a hollow cylindrical, isostatic pressure pot a mold cavity for that too pressing product between an axial, vertically extendable Steel mandrel and one concentrically arranged and hollow cylindrical shaping membrane made of rubber-elastic Material is formed, which shaping membrane is clamped at both ends and to the pressure pot towards one acted upon by a hydraulic pressure source Delimits the pressure space.
  • Such a device is from DE-A-28 25 611 known.
  • Ceramic Pipes are made that are relatively thin, however often have insufficient dimensional accuracy and which has a burnout safety of over 1000 ° C of the pipe must have. At the same time, it must be absolutely gastight before and after the burnout process according to DIN 18 160 part 6 and extensive vapor diffusion security be available.
  • the approximately 35% imaginative, i.e. plastic substance, e.g. Clay and about 65% non-figurative substance, e.g. Chamotte exhibit.
  • an internal steel mandrel is provided at the bottom End a protruding edge and a surrounding, slightly higher annular insert made of rubber or Has plastic, which as the shaping insert forms the lower end of the mold cavity.
  • the top one The mold cavity is also closed ring-shaped insert on a heel of the steel mandrel rests and also to shape the upper Front of the product to be molded.
  • the top The end of the steel mandrel is from one together with The upper insert is surrounded by a removable upper table after opening the upper end of the mold cavity releases the ceramic mass to be pressed in fill the mold cavity.
  • the present Invention the object of a press device to create an optimally dimensionally stable Manufacture of ceramic products is possible, i.e. a true-to-contour pressing without the need for a mechanical finishing. This is also supposed to be possible the pressed body during the pressing process to be provided with permanent and true-to-size contours.
  • the invention provides that the annular gap above the mold cavity between Pressure pot and steel mandrel by means of a cylindrical, Lockable steel ring that can be retracted and extended vertically and is limited and that the annular gap below of the mold cavity between the pressure pot and Steel mandrel by means of a conical, vertically in and out extendable steel ring can be locked and limited and that after isostatic pressing into the mold cavity introduced ceramic mass of the steel mandrel together with the lower conical steel ring and the Completely pressed product can be extended vertically downwards is, the conical immediately after the narrowest point Extension enables demolding.
  • the ones adjacent to the mold cavity can be used End faces of the steel rings as shaping elements be trained.
  • end faces the steel rings are stepped in opposite directions are offset to form a tongue and groove connection for adjoining tubular products.
  • the lower steel ring should be used for the shaping the groove and the upper steel ring for shaping the Spring be formed because of the suspension of the Mass would be destroyed in the pressure reduction the spring ..
  • the shaping membrane is expediently on its Outer circumference of a perforated one Support tube surrounded by the top and bottom of hook-shaped approaches that the effect of sealing lips have encompassed the shaping membrane.
  • the shaping membrane can additionally on her Inner surface to be contoured, this contouring from longitudinal parallel ribs or grooves can exist to create a finned tube.
  • the upper hollow cylindrical steel ring is convenient connected to the top table of the device and extendable together with this.
  • a conically tapering can be in this steel ring Be used in the ring in the shape of a cone tapered head of the steel mandrel is guided.
  • the lower steel ring is expediently at least a graded reduction in diameter of the Steel mandrel attached and together with the steel mandrel extendable downwards.
  • the steel mandrel in its upper area at least one radially extendable Driver pin, which after extending the upper metal ring the gap between mandrel and pressure pot interspersed and when pulling out the steel mandrel takes the finished product with them below.
  • the pressing device on the outside a hollow cylindrical, isostatic Pressure pot 1 on.
  • This pressure pot 1 encloses the inside a pressure chamber 2, in the one with openings 3 provided support tube 4 is inserted.
  • this support tube 4 On the inner circumference this support tube 4 is the actual, also hollow cylindrical shaping membrane 5 made of an elastic Material.
  • This membrane 5 encompasses the top and lower end with hook-shaped lugs 6 and 7 that Support tube 4 and is encompassing the membrane ends Rings 8 and 9 fixed against the pressure pot 1.
  • Axial in the pressure pot 1 is a steel mandrel 11 as the inside Shaping element used between his Outer surface and the inner surface of the molding membrane 5 the actual mold cavity 12 for that to be manufactured Product encloses.
  • This mold cavity 12 settles in the upper area practically over the effective length of the shaping membrane 5 beyond and over the entire length of the pressure pot 1 as an annular gap of approximately the same width as that of the Mold cavity 12 continues.
  • the mold cavity faces the narrowest Set up a conical extension so that the Remove the mandrel with the pressed tube only one if possible small resistance must be overcome.
  • the upper annular gap is cylindrical Steel ring 13, the one with the removable upper table 14 is connected, lockable during the Annular gap below the mold cavity 12 with a Steel ring 15 is closed, with the down extractable mandrel 11 is connected and by this is taken away.
  • Fig. 2 is in particular on an enlarged scale shown upper and lower area of the pressing device.
  • Shaping elements 16 and 17 are formed, for example a tongue and groove connection for connecting To form tubes. It is advisable when the lower shaping member 17 to form the Groove and the upper shaping element 16 to form the Serve spring while stepping opposite each other are discontinued.
  • the lower steel ring 15 is shrunk onto the steel mandrel 11 and form-fitting over several step-shaped Indentations 20, 21 and 23 connected to when pulling out of the steel mandrel 11 safely taken down by this to become.
  • the shaping elements 16 and 17 also the corresponding ones Contours in the end faces of the product to be pressed embossed.
  • the pressure chamber 2 relieved again, so that the shaping membrane 5 in returns to its original position, moving away from pressed product 26, for example a ceramic tube, away.
  • pressed product 26 for example a ceramic tube
  • the process is carried out by a vacuum source supports, so that an absolute concern of the membrane to the support tube and the filling space is always accurate has the same volume.
  • the pressed tube will also have restoring forces 26 loosen something from the steel mandrel 11.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical & Material Sciences (AREA)
  • Ceramic Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Press-Shaping Or Shaping Using Conveyers (AREA)
  • Shaping By String And By Release Of Stress In Plastics And The Like (AREA)
  • Powder Metallurgy (AREA)

Abstract

The shaping membrane (5) is tensioned at both ends and limits a pressure chamber (2) fed from a hydraulic pressure source. A ring gap above the shape hollow space (12) between the pressure pot (1) and the steel mandrel (11) is blockable and limitable by means of a cylindrical, vertical steel ring (13) movable in and out. The ring gap beneath the shape hollow space between the pressure pot and the steel mandrel is blockable and limitable by means of a conical, vertically movable steel ring (15). After isostatic pressing of the ceramic pulp in the shape hollow space, the steel mandrel (11) together with the lower conical steel ring (15) and the ready pressed product (26) moves vertically downwards.

Description

Die Erfindung bezieht sich auf eine Vorrichtung zur Herstellung von zumindest angenähert hohlzylindrischen Produkten, insbesondere dünnwandigen Rohren, aus keramischen, feinteiligen Werkstoffen durch isostatisches Pressen, bei der innerhalb eines hohlzylindrischen, isostatischen Drucktopfes ein Formhohlraum für das zu pressende Produkt zwischen einem axialen, vertikal ausziehbaren Stahldorn und einer konzentrisch angeordneten und hohlzylindrischen Formgebungsmembran aus gummielastischem Material gebildet ist, welche Formgebungsmembran an beiden Enden eingespannt ist und zum Drucktopf hin einen von einer hydraulischen Druckquelle beaufschlagten Druckraum abgrenzt.The invention relates to a device for Production of at least approximately hollow cylindrical Products, especially thin-walled pipes, made of ceramic, finely divided materials through isostatic Pressing, in which within a hollow cylindrical, isostatic pressure pot a mold cavity for that too pressing product between an axial, vertically extendable Steel mandrel and one concentrically arranged and hollow cylindrical shaping membrane made of rubber-elastic Material is formed, which shaping membrane is clamped at both ends and to the pressure pot towards one acted upon by a hydraulic pressure source Delimits the pressure space.

Eine derartige Vorrichtung ist aus der DE-A-28 25 611 bekannt. Mit einer solchen Presse können keramische Rohre hergestellt werden, die relativ dünn sind, jedoch eine oft nicht ausreichende Maßhaltigkeit aufweisen und die eine Ausbrennsicherheit von über 1000 °C des Rohres aufweisen müssen. Gleichzeitig muß eine absolute Gasdichtigkeit vor und nach dem Ausbrennvorgang nach DIN 18 160 Teil 6 sowie eine weitgehende Dampfdiffusionssicherheit erreichbar sein. Im allgemeinen werden dafür als Grundmaterial mechanisch granulierte Massen verwendet, die etwa 35% bildsame, d.h. plastische Substanz, z.B. Ton und etwa 65% unbildsame Substanz, z.B. Schamotte, aufweisen.Such a device is from DE-A-28 25 611 known. With such a press, ceramic Pipes are made that are relatively thin, however often have insufficient dimensional accuracy and which has a burnout safety of over 1000 ° C of the pipe must have. At the same time, it must be absolutely gastight before and after the burnout process according to DIN 18 160 part 6 and extensive vapor diffusion security be available. Generally, for that mechanically granulated masses are used as the base material, the approximately 35% imaginative, i.e. plastic substance, e.g. Clay and about 65% non-figurative substance, e.g. Chamotte, exhibit.

Bei der Preßvorrichtung nach dem Stand der Technik ist ein innenliegender Stahldorn vorgesehen, der am unteren Ende einen überstehenden Rand und eine diesen umgebenden, etwas höhere ringförmige Einlage aus Gummi oder Kunststoff aufweist, die als formgebende Einlage den unteren Abschluß des Formenhohlraumes bildet. Den oberen Abschluß des Formhohlraumes bildet eine ebenfalls ringförmige Einlage, die auf einem Absatz des Stahldorns aufruht und ebenfalls zur Formgebung der oberen Stirnseite des zu formenden Produktes dient. Das obere Ende des Stahldorns ist dabei von einem zusammen mit der oberen Einlage abnehmbaren Obertisch umgeben, der nach Auffahren das obere Ende des Formenhohlraumes freigibt, um die zu verpressende keramische Masse in den Formhohlraum einzufüllen. Schwierigkeiten ergeben sich dabei jedoch für eine ordnungsgemäße und gleichmäßige Füllung des Formhohlraumes, da ein Zusammenpressen der keramischen Masse von oben nur in einem sehr geringen Umfange entsprechend der Höhe der ringförmigen EinLage möglich ist und weil darüber hinaus beim Verschließen des Preßwerkzeuges "Verblasungen" unvermeidbar sind und dadurch eine Verfälschung des Füllgewichtes der Masse eintritt. Dadurch wird oftmals nur eine wenig homogene Füllung erhalten, so daß die fertigen Produkte weniger maßhaltig sind und ggf. nachbearbeitet werden müssen, insbesondere im Bereich der stirnseitigen Partien des Preßlings wie z.B. bei der Einformung von Nut und Feder.In the pressing device according to the prior art an internal steel mandrel is provided at the bottom End a protruding edge and a surrounding, slightly higher annular insert made of rubber or Has plastic, which as the shaping insert forms the lower end of the mold cavity. The top one The mold cavity is also closed ring-shaped insert on a heel of the steel mandrel rests and also to shape the upper Front of the product to be molded. The top The end of the steel mandrel is from one together with The upper insert is surrounded by a removable upper table after opening the upper end of the mold cavity releases the ceramic mass to be pressed in fill the mold cavity. Difficulties arise however, opt for a proper and even Filling of the mold cavity because of a compression the ceramic mass from above only in a very small amount Scope according to the height of the ring-shaped insert is possible and because it also closes of the pressing tool "blows" inevitable are and therefore a falsification of the filling weight the crowd enters. This often only get a little homogeneous filling, so that the finished Products are less true to size and reworked if necessary must be, especially in the area of end parts of the compact such as in the Groove tongue and groove.

Nach dem üblichen Verpressen durch Druckbeaufschlagung der den Formhohlraum außen begrenzenden Membran und anschließender Entlastung der Membran wird zunächst der Obertisch abgezogen und der Dorn zusammen mit dem gepreßten Produkt nach oben herausgezogen, wo dann das Produkt wegen der elastischen Rückformung des Preßlings vom Dorn entnommen werden kann.After the usual pressing by pressurization the membrane which delimits the mold cavity on the outside and subsequent The membrane is first relieved Pulled off the top table and the mandrel together with the pressed Product pulled up, where then that Product due to the elastic recovery of the compact can be removed from the mandrel.

Beim Herausziehen des Dorns mit dem gepreßten Rohr muß dabei das obere Ende der Membran passiert werden. Diese engste Stelle darf nur sehr kurz sein, da das Rohr sonst steckenbleiben würde. Es ist daher erforderlich, im Anschluß an diesen "Bottle-Neck" eine deutliche Erweiterung des Querschnittes herbeizuführen. Beim Verschließen des Werkzeuges nach erfolgter Füllung ist jedoch diese Querschnittserweiterung sehr problematisch, da unbestimmbare Masseverblasungen auftreten.When pulling out the mandrel with the pressed tube must the upper end of the membrane being passed. This narrowest point may only be very short because the pipe otherwise would get stuck. It is therefore necessary following this "bottle neck" a significant expansion of the cross section. When closing of the tool after filling is complete this cross-sectional expansion very problematic, because indeterminable mass blows occur.

Ausgehend von diesem Stand der Technik liegt der vorliegenden Erfindung die Aufgabe zugrunde, eine Preßvorrichtung zu schaffen, mit der ein optimal maßhaltiges Herstellen von keramischen Produkten möglich ist, d.h. ein endkonturgetreues Pressen ohne das Erfordernis einer mechanischen Nachbearbeitung. Dadurch soll es auch möglich sein, die gepreßten Körper während des Preßvorganges mit dauerhaften und maßgetreuen Konturen zu versehen. Based on this prior art, the present Invention, the object of a press device to create an optimally dimensionally stable Manufacture of ceramic products is possible, i.e. a true-to-contour pressing without the need for a mechanical finishing. This is also supposed to be possible the pressed body during the pressing process to be provided with permanent and true-to-size contours.

Zur Lösung dieser Aufgabe ist erfindungsgemäß vorgesehen, daß der Ringspalt oberhalb des Formhohlraumes zwischen Drucktopf und Stahldorn mittels eines zylindrischen, vertikal ein- und ausfahrbaren Stahlringes absperrbar und begrenzbar ist und daß der Ringspalt unterhalb des Formhohlraumes zwischen Drucktopf und Stahldorn mittels eines konischen, vertikal ein- und ausfahrbaren Stahlringes absperrbar und begrenzbar ist und daß nach isostatischem Verpressen der in den Formhohlraum eingebrachten keramischen Masse der Stahldorn zusammen mit dem unteren konischen Stahlring sowie dem fertig gepreßten Produkt vertikal nach unten ausfahrbar ist, wobei unmittelbar nach der engsten Stelle die konische Erweiterung das Entformen ermöglicht.To achieve this object, the invention provides that the annular gap above the mold cavity between Pressure pot and steel mandrel by means of a cylindrical, Lockable steel ring that can be retracted and extended vertically and is limited and that the annular gap below of the mold cavity between the pressure pot and Steel mandrel by means of a conical, vertically in and out extendable steel ring can be locked and limited and that after isostatic pressing into the mold cavity introduced ceramic mass of the steel mandrel together with the lower conical steel ring and the Completely pressed product can be extended vertically downwards is, the conical immediately after the narrowest point Extension enables demolding.

Damit kann die sogenannte engste Stelle, auf die zwingend eine Erweiterung folgen muß, nach unten verlegt werden. Während des Füllvorganges ist diese bereits verschlossen, so daß kein Verblasen von Masse auftreten kann. Der obere Ringspalt kann jedoch hingegen dem Stand der Technik auf beliebige Länge völlig zylindrisch ausgeführt werden, so daß beim Einfahren des Oberstempels die Masse axial frei wählbar verdichtet werden kann, ohne daß es zu Verblasungen kommt.This allows the so-called narrowest point to be mandatory an extension must follow, moved down will. This is already during the filling process closed, so that no blowing of mass occur can. The upper annular gap, however, can State of the art completely cylindrical for any length run so that when retracting the The upper stamp compresses the mass axially freely selectable can be made without blowing.

Mit diesen Stahlringen ist eine optimale Vorverdichtung der in den Formhohlraum eingebrachten keramischen Masse möglich, so daß damit eine sehr homogene Füllung erreicht werden kann mit besonders guter Ausbildung der stirnseitigen Flächen, wie z.B. Nut und Feder. With these steel rings is an optimal pre-compression the ceramic mass introduced into the mold cavity possible, so that a very homogeneous filling is achieved can be with particularly good training end faces, e.g. Tongue and groove.

Dabei können die an den Formhohlraum angrenzenden Stirnflächen der Stahlringe als Formgebungselemente ausgebildet sein.The ones adjacent to the mold cavity can be used End faces of the steel rings as shaping elements be trained.

Eine Möglichkeit besteht darin, daß die Stirnflächen der Stahlringe einander entgegengesetzt stufenförmig abgesetzt sind zur Bildung einer Nut-Feder-Verbindung für einanderanschließende rohrförmige Produkte.One possibility is that the end faces the steel rings are stepped in opposite directions are offset to form a tongue and groove connection for adjoining tubular products.

Dabei sollte der untere Stahlring für die Formgebung der Nut und der obere Stahlring für die Formgebung der Feder ausgebildet sein, weil durch die Auffederung der Masse beim Druckabbau die Feder zerstört würde..The lower steel ring should be used for the shaping the groove and the upper steel ring for shaping the Spring be formed because of the suspension of the Mass would be destroyed in the pressure reduction the spring ..

Zweckmäßigerweise ist die Formgebungsmembran an ihrem Außenumfang von einem mit Durchbrechungen versehenen Stützrohr umgeben, das am oberen und unteren Ende von hakenförmigen Ansätzen, die die Wirkung von Dichtlippen aufweisen, der Formgebungsmembran umgriffen ist.The shaping membrane is expediently on its Outer circumference of a perforated one Support tube surrounded by the top and bottom of hook-shaped approaches that the effect of sealing lips have encompassed the shaping membrane.

Die Formgebungsmembran kann dabei zusätzlich auf ihrer Innenoberfläche konturiert sein, wobei diese Konturierung aus längsverlaufenden parallelen Rippen oder Rillen bestehen kann, um damit ein Rippenrohr zu schaffen.The shaping membrane can additionally on her Inner surface to be contoured, this contouring from longitudinal parallel ribs or grooves can exist to create a finned tube.

Der obere hohlzylindrische Stahlring ist zweckmäßigerweise mit dem Obertisch der Vorrichtung verbunden und mit diesem zusammen nach oben ausfahrbar. The upper hollow cylindrical steel ring is convenient connected to the top table of the device and extendable together with this.

Ferner kann in diesen Stahlring ein sich konisch verjüngender Ring eingesetzt sein, in dem der kegelformig zulaufende Kopf des Stahldorns geführt ist.Furthermore, a conically tapering can be in this steel ring Be used in the ring in the shape of a cone tapered head of the steel mandrel is guided.

Der untere Stahlring ist zweckmäßigerweise auf mindestens eine abgestufte Durchmesserverringerung des Stahldorns aufgesetzt und zusammen mit dem Stahldorn formschlüssig nach unten ausziehbar.The lower steel ring is expediently at least a graded reduction in diameter of the Steel mandrel attached and together with the steel mandrel extendable downwards.

Darüberhinaus ist es von Vorteil, wenn der Stahldorn in seinem oberen Bereich mindestens einen radial ausfahrbaren Mitnehmerstift aufweist, der nach Ausfahren des oberen Metallringes den Spalt zwischen Dorn und Drucktopf durchsetzt und beim Ausziehen des Stahldorns nach unten das gefertigte Produkt mitnimmt.In addition, it is advantageous if the steel mandrel in its upper area at least one radially extendable Driver pin, which after extending the upper metal ring the gap between mandrel and pressure pot interspersed and when pulling out the steel mandrel takes the finished product with them below.

Anhand einer schematischen Zeichnung sind Aufbau und Funktionsweise von Ausführungsbeispielen nach der Erfindung näher erläutert. Dabei zeigen:

Fig. 1
eine Seitenansicht mit Teillängsschnitt einer vollständigen Preßvorrichtung und
Fig. 2
eine vergrößerte schnittdarstellung in entsprechender Verkürzung.
The structure and mode of operation of exemplary embodiments according to the invention are explained in more detail using a schematic drawing. Show:
Fig. 1
a side view with partial longitudinal section of a complete pressing device and
Fig. 2
an enlarged sectional view in a corresponding shortening.

Wie man aus Fig. 1 ersieht, weist die Preßvorrichtung außenliegend einen hohlzylindrischen, isostatischen Drucktopf 1 auf. Dieser Drucktopf 1 umschließt nach innen eine Druckkammer 2, in die ein mit Durchbrechungen 3 versehenes Stützrohr 4 eingesetzt ist. Am Innenumfang dieses Stützrohres 4 liegt die eigentliche, ebenfalls hohlzylindrische Formgebungsmembran 5 aus einem elastischen Material an. Diese Membran 5 umgreift am oberen und unteren Ende mit hakenförmigen Ansätzen 6 und 7 das Stützrohr 4 und ist mit die Membranenden umgreifenden Ringen 8 und 9 gegen den Drucktopf 1 fixiert.As can be seen from Fig. 1, the pressing device on the outside a hollow cylindrical, isostatic Pressure pot 1 on. This pressure pot 1 encloses the inside a pressure chamber 2, in the one with openings 3 provided support tube 4 is inserted. On the inner circumference this support tube 4 is the actual, also hollow cylindrical shaping membrane 5 made of an elastic Material. This membrane 5 encompasses the top and lower end with hook-shaped lugs 6 and 7 that Support tube 4 and is encompassing the membrane ends Rings 8 and 9 fixed against the pressure pot 1.

Axial in den Drucktopf 1 ist ein Stahldorn 11 als inneres Formgebungselement eingesetzt, der zwischen seiner Außenfläche und der Innenfläche der Formgebungsmembran 5 den eigentlichen Formhohlraum 12 für das herzustellende Produkt umschließt.Axial in the pressure pot 1 is a steel mandrel 11 as the inside Shaping element used between his Outer surface and the inner surface of the molding membrane 5 the actual mold cavity 12 for that to be manufactured Product encloses.

Dieser Formhohlraum 12 setzt sich im oberen Bereich praktisch über die wirksame Länge der Formgebungsmembran 5 hinaus und über die Gesamtlänge des Drucktopfes 1 als Ringspalt von etwa gleicher Breite wie der des Formhohlraumes 12 fort.This mold cavity 12 settles in the upper area practically over the effective length of the shaping membrane 5 beyond and over the entire length of the pressure pot 1 as an annular gap of approximately the same width as that of the Mold cavity 12 continues.

Im unteren Bereich weist der Formhohlraum nach der engsten Stelle eine konische Erweiterung auf, so daß beim Entnehmen des Dorns mit dem gepreßten Rohr nur ein möglichst kleiner Widerstand überwunden werden muß.In the lower area, the mold cavity faces the narrowest Set up a conical extension so that the Remove the mandrel with the pressed tube only one if possible small resistance must be overcome.

Der obere Ringspalt ist dabei mit einem zylindrischen Stahlring 13, der mit dem nach oben abziehbaren Obertisch 14 verbunden ist, verschließbar, während der Ringspalt unterhalb des Formhohlraumes 12 mit einem Stahlring 15 verschlossen ist, der mit dem nach unten ausziehbaren Preßdorn 11 verbunden ist und von diesem mitgenommen wird. The upper annular gap is cylindrical Steel ring 13, the one with the removable upper table 14 is connected, lockable during the Annular gap below the mold cavity 12 with a Steel ring 15 is closed, with the down extractable mandrel 11 is connected and by this is taken away.

In Fig. 2 ist im vergrößerten Maßstab insbesondere der obere und der untere Bereich der Preßvorrichtung dargestellt.In Fig. 2 is in particular on an enlarged scale shown upper and lower area of the pressing device.

Wie man daraus ersieht, sind die an den Formhohlraum 12 angrenzenden Stirnflächen der Stahlringe 13 und 15 als Formgebungselemente 16 und 17 ausgebildet, um beispielsweise eine Nut-Feder-Verbindung für aneinanderanschließende Rohre zu bilden. Dabei ist es zweckmäßig, wenn das untere Formgebungselement 17 zur Bildung der Nut und das obere Formgebungselement 16 zur Bildung der Feder dienen und dabei einander entgegengesetzt stufenförmig abgesetzt sind.As can be seen from this, they are on the mold cavity 12 adjacent end faces of the steel rings 13 and 15 as Shaping elements 16 and 17 are formed, for example a tongue and groove connection for connecting To form tubes. It is advisable when the lower shaping member 17 to form the Groove and the upper shaping element 16 to form the Serve spring while stepping opposite each other are discontinued.

In den oberen Stahlring 13, der mit dem Obertisch 14 verbunden ist, ist auf der Innenseite ein konischer Ring 18 eingesetzt, der zur Führung und exakten Positionierung des kegelförmigen Kopfes 19 des Stahldorns 11 in seiner eingefahrenen Stellung dient.In the upper steel ring 13, which with the upper table 14th is tapered on the inside Ring 18 used for guidance and exact positioning of the conical head 19 of the steel mandrel 11 serves in its retracted position.

Der untere Stahlring 15 ist auf den Stahldorn 11 aufgeschrumpft und formschlüssig über mehrere stufenförmige Einziehungen 20, 21 und 23 verbunden, um beim Ausziehen des Stahldorns 11 nach unten von diesem sicher mitgenommen zu werden.The lower steel ring 15 is shrunk onto the steel mandrel 11 and form-fitting over several step-shaped Indentations 20, 21 and 23 connected to when pulling out of the steel mandrel 11 safely taken down by this to become.

Die Funktionsweise dieser Preßvorrichtung ist nunmehr die folgende. Bei noch abgezogenem Obertisch 14 zusammen mit dem oberen Stahlring 13 und eingefahrenem Stahldorn 11 wird der Formhohlraum mit der zu verpressenden keramischen Masse gefüllt, bis der Formhohlraum 12 etwa bis zur Oberkante 23 der Formgebungsmembran 5 gefüllt ist. Hierbei kann die gewünschte Füllhöhe ganz exakt mit Hilfe einer rotierenden Streichvorrichtung eingestellt werden, indem überschüssige Masse über im Preßdorn befindliche Bohrungen 31 in das Dorninnere und damit ins Freie abgeführt werden kann. Durch Niederfahren des Obertisches 14 und des Stahlringes 15 wird die keramische Masse im Formhohlraum 12 zusammengepreßt, um dadurch eine homogene Füllung zu erreichen. Durch die parallelen Wandungen des oberen Stahlringes 13 und die parallelen Wandungen des Spaltes, in den dieser Stahlring 13 eintaucht, wird die Masse im Formhohlraum 12 sicher zusammengepreßt, ohne daß sie nach oben am Stahlring 13 vorbei ausgeblasen werden kann.The operation of this press device is now the following. With the upper table 14 still removed with the upper steel ring 13 and retracted Steel mandrel 11 becomes the mold cavity with that to be pressed ceramic mass filled until the mold cavity 12 approximately up to the upper edge 23 of the shaping membrane 5 is filled. Here, the desired fill level can be entirely exactly with the help of a rotating coating device be adjusted by excess mass over in Press mandrel bores 31 in the mandrel interior and so that it can be discharged outdoors. By driving down the upper table 14 and the steel ring 15 is the ceramic mass in the mold cavity 12 compressed to thereby achieving a homogeneous filling. Through the parallel walls of the upper steel ring 13 and the parallel walls of the gap in which this steel ring 13 immersed, the mass in the mold cavity 12 securely pressed together, without them being pushed upwards Steel ring 13 can be blown out.

Bei dieser Vorverdichtung werden durch die Formgebungselemente 16 und 17 auch gleich die entsprechenden Konturen in die Stirnflächen des zu pressenden Produktes eingeprägt.With this pre-compression, the shaping elements 16 and 17 also the corresponding ones Contours in the end faces of the product to be pressed embossed.

Anschließend wird die Druckkammer 2 über eine externe Druckquelle 24 und zugehörige Leitungen 25 - wie in Fig. 1 dargestellt - mit einer hydraulischen Flüssigkeit gefüllt. Diese hydraulische Flüssigkeit drückt über die Durchbrechungen 3 im Stützrohr 4 auf die Formgebungsmembran 5 und preßt diese unter entsprechend hohem Druck gegen die eingefüllte keramische Masse, bis diese auf die vorgegebene Form verdichtet ist.Then the pressure chamber 2 via an external Pressure source 24 and associated lines 25 - as in Fig. 1 shown - with a hydraulic fluid filled. This hydraulic fluid presses over the openings 3 in the support tube 4 on the shaping membrane 5 and presses them under a correspondingly high Pressure against the filled ceramic mass, up to this is compressed to the specified shape.

Nach der entsprechenden Formgebung wird die Druckkammer 2 wieder entlastet, so daß die Formgebungsmembran 5 in ihre Ausgangsstellung zurückkehrt und sich dabei vom gepreßten Produkt 26, beispielsweise einem Keramikrohr, entfernt. Durch eine Unterdruckquelle wird der Vorgang unterstützt, so daß ein absolutes Anliegen der Membran an das Stützrohr erfolgt und der Füllraum immer genau das gleiche Volumen aufweist. Durch die vorhandenen Rückstellkräfte wird sich dabei auch das gepreßte Rohr 26 etwas vom Stahldorn 11 lösen.After the appropriate shaping, the pressure chamber 2 relieved again, so that the shaping membrane 5 in returns to its original position, moving away from pressed product 26, for example a ceramic tube, away. The process is carried out by a vacuum source supports, so that an absolute concern of the membrane to the support tube and the filling space is always accurate has the same volume. Through the existing ones The pressed tube will also have restoring forces 26 loosen something from the steel mandrel 11.

Anschließend wird der Obertisch 14 zusammen mit dem oberen Stahlring 13 nach oben herausgezogen.Then the upper table 14 together with the pulled out upper steel ring 13 upwards.

Im Kopf 19 des Stahldorns 11 befindet sich darüberhinaus noch ein ausfahrbarer, stiftförmiger Mitnehmer 27, der durch Einwirken eines kegelförmigen und nach oben verschieblichen Ringes 28 und entsprechenden Federn 28 und 30 nach Ausfahren des oberen Stahlringes 13 in den Spalt zwischen Stahldorn 11 und Drucktopf 1 ausfährt.In addition, is located in the head 19 of the steel mandrel 11 another extendable, pin-shaped driver 27 by the action of a conical and after above movable ring 28 and corresponding springs 28 and 30 after extending the upper steel ring 13 extends into the gap between steel mandrel 11 and pressure pot 1.

Anschließend wird der Stahldorn 11 nach unten ausgezogen, wobei dann über den ausfahrbaren Mitnehmer 27 das gepreßte Rohr 26 mit nach unten herausgeführt wird. Anschließend kann dann das Rohr 26 vom Stahldorn 11 abgezogen und unmittelbar weiterverarbeitet, d.h. gebrannt werden.Then the steel mandrel 11 is pulled down, the then via the extendable driver 27 pressed tube 26 is led out with down. Subsequently can then pull the tube 26 from the steel mandrel 11 and immediately processed, i.e. burned will.

Es ist dabei auch möglich, die Formgebungsmembran 5 auf ihrer Innenfläche mit Konturen, beispielsweise in Form von parallelen Rippen oder Rillen, zu versehen, um damit ein entsprechend konturiertes Produkt zu erhalten. It is also possible to open the shaping membrane 5 their inner surface with contours, for example in shape parallel ribs or grooves to provide to receive a correspondingly contoured product.

Außerdem ist es nur auf diese Weise möglich, auch ein Rohr mit einer glockenförmigen Muffe zu pressen.Besides, it is only possible in this way, even one Press pipe with a bell-shaped sleeve.

Durch die Gestaltung und Anordnung des oberen Stahlringes 13 ist eine hohe Uberfüllung des Formhohlraumes möglich, die dann auf das gewünschte Volumen vorverdichtet wird.Due to the design and arrangement of the upper steel ring 13 is a high overfill of the mold cavity possible, which is then pre-compressed to the desired volume becomes.

Durch die Gestaltung und Ausbildung dieser Preßvorrichtung ist ein sehr genaues endkonturgetreues Pressen der Teile möglich, ohne daß eine Nachbearbeitung erforderlich ist. Die Qualität der gepreßten Produkte in Bezug auf Maßhaltigkeit ist dabei so hoch wie bei einem Pressen mit stählernen Matritzen und gewährt damit eine absolute Formtreue, so daß die erhaltenen Produkte ohne Nachbearbeitung weiterverarbeitet werden können.By designing and designing this press is a very precise final contour pressing of the Parts possible without the need for post-processing is. The quality of the pressed products in relation dimensional accuracy is as high as that of a press with steel matrices and thus guarantees an absolute Shape retention, so that the products obtained without Postprocessing can be processed further.

Claims (11)

  1. Device for making at least approximately cylindrical tubular products, more particularly thin-walled tubes, of fine-particle, ceramic materials by isostatic compacting, in which within a cylindrical tubular isostatic pressure pot (1) a molding cavity (12) for the product (26) to be compacted is formed between an axially vertically extensible steel mandrel (11) and a concentrically arranged and cylindrical tubular molding diaphragm (5) of an elastomeric material, the molding diaphragm (5) being clamped in place at both ends and defined in the direction of the pressure pot (1) by a pressure chamber (2) pressurizable by a hydraulic pressure source (24), characterized in that the annular gap above the molding cavity (12) between said pressure pot (1) and said steel mandrel (11) can be shut off and defined by means of a cylindrical, vertically extensible and retractable steel ring (13) and that the annular gap below said molding cavity (12) between said pressure pot (1) and said steel mandrel (11) can be shut off and defined by means of a conical vertically extensible and retractable steel ring (15) and that following isostatic compacting of said ceramic mass inserted in said molding cavity (12) said steel mandrel (11) together with the lower conical steel ring (15) as well as said finish-compacted product (26) can be extended downwards, the conical flare directly following the bottleneck (32) permitting mold release.
  2. The device as set forth in claim 1, characterized in that the face surface areas (16, 17) of said steel rings (13, 15) defining said molding cavity (12) are configured as molding elements.
  3. The device as set forth in claim 2, characterized in that said face surface areas (16, 17) of said steel rings (13, 15) are offset stepped opposingly from each other to form a tongue and groove connection for adjoining tubular products.
  4. The device as set forth in claim 3, characterized in that said lower steel ring (15) is configured for molding said groove and said upper steel ring is configured for molding said tongue.
  5. The device as set forth in claim 1, characterized in that said molding diaphragm (5) is surrounded at its outer circumference by a ported supporting tube (4), clasped at its top and bottom end by hook-shaped appendages (6, 7) of said molding diaphragm (5).
  6. The device as set forth in claim 1 or 5, characterized in that said molding diaphragm (5) is contoured on its inner surface.
  7. The device as set forth in claim 6, characterized in that said contouring of said inner surface of said molding diaphragm (5) consists of longitudinally oriented parallely arranged ribs or grooves.
  8. The device as set forth in claim 1, characterized in that said upper cylindrical tubular steel ring (13) is connected to the upper table (14) of said device and is extensible upwards together therewith.
  9. The device as set forth in claim 8, characterized in that inserted in said upper steel ring (13) is a conical ring (18) in which the conical head (19) of said steel mandrel (11) is guided.
  10. The device as set forth in claim 1, characterized in that said lower steel ring (15) is mounted on at least one stepped recess (20, 21, 22) of said steel mandrel (11) and is extractable downwards positively together with said steel mandrel (11).
  11. The device as set forth in claim 1, characterized in that said steel mandrel (11) comprises in its upper portion at least one radially extensible slave pin (27) which following extension of said upper metal ring (13) passes through said opened gap and slaves said finished product (26) in the downwards extraction movement of said steel mandrel (11).
EP95102778A 1994-03-04 1995-02-27 Device for making cylindrical tubular products Expired - Lifetime EP0670207B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4407299 1994-03-04
DE4407299A DE4407299C1 (en) 1994-03-04 1994-03-04 Device for producing hollow-cylindrical products

Publications (2)

Publication Number Publication Date
EP0670207A1 EP0670207A1 (en) 1995-09-06
EP0670207B1 true EP0670207B1 (en) 1998-09-09

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Application Number Title Priority Date Filing Date
EP95102778A Expired - Lifetime EP0670207B1 (en) 1994-03-04 1995-02-27 Device for making cylindrical tubular products

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EP (1) EP0670207B1 (en)
AT (1) ATE170794T1 (en)
DE (2) DE4407299C1 (en)
ES (1) ES2123169T3 (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4444774C1 (en) * 1994-12-15 1996-03-07 Klaus Dipl Ing Strobel Prodn. of ceramic products, esp. thin-walled pipes
DE19547775C1 (en) 1995-12-20 1997-07-31 Klaus Dipl Ing Strobel Device for producing socket pipe moldings and socket pipe mold produced using the device
FR2757099B1 (en) * 1997-12-15 1999-07-30 Ceramiques Tech Soc D TOOLS AND METHOD FOR PRODUCING CERAMIC TUBES USING THE SAME

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3172153A (en) * 1961-10-11 1965-03-09 David G Loomis Apparatus for molding powdered materials
US3193900A (en) * 1963-09-30 1965-07-13 Pacific Clay Products Apparatus for manufacturing clay pipe
SE322874B (en) * 1966-12-27 1970-04-20 Asea Ab

Also Published As

Publication number Publication date
ES2123169T3 (en) 1999-01-01
DE59503475D1 (en) 1998-10-15
DE4407299C1 (en) 1995-05-11
EP0670207A1 (en) 1995-09-06
ATE170794T1 (en) 1998-09-15

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