EP0097750A2 - Verfahren und Vorrichtung zum Formen von Eindrücken auf keramische Rohre - Google Patents

Verfahren und Vorrichtung zum Formen von Eindrücken auf keramische Rohre Download PDF

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Publication number
EP0097750A2
EP0097750A2 EP82401224A EP82401224A EP0097750A2 EP 0097750 A2 EP0097750 A2 EP 0097750A2 EP 82401224 A EP82401224 A EP 82401224A EP 82401224 A EP82401224 A EP 82401224A EP 0097750 A2 EP0097750 A2 EP 0097750A2
Authority
EP
European Patent Office
Prior art keywords
tube
wheels
axes
wheel
pair
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.)
Withdrawn
Application number
EP82401224A
Other languages
English (en)
French (fr)
Other versions
EP0097750A3 (de
Inventor
Jacques Gillot
Paul Tritten
Jean-Louis Weber
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.)
Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Original Assignee
Commissariat a lEnergie Atomique CEA
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
Application filed by Commissariat a lEnergie Atomique CEA filed Critical Commissariat a lEnergie Atomique CEA
Priority to EP82401224A priority Critical patent/EP0097750A3/de
Publication of EP0097750A2 publication Critical patent/EP0097750A2/de
Publication of EP0097750A3 publication Critical patent/EP0097750A3/de
Withdrawn legal-status Critical Current

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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
    • B28B21/92—Methods or apparatus for treating or reshaping
    • B28B21/98—Methods or apparatus for treating or reshaping for reshaping, e.g. by means of reshape moulds

Definitions

  • the present invention relates to a method and a device for making impressions on ceramic tubes and ceramic tubes provided with impressions.
  • microporous tubes are used to produce the diffuser assemblies used for the implementation of this isotopic enrichment method. It is known that these microporous tubes are generally in fact produced in two stages. In a first step, a macro-porous ceramic tube also called a “support” is produced. In a second step, an internal microporous deposit is produced which makes it possible to obtain a tube called a “barrier”, ultimately having the porosity required to set in motion. uses the gas diffusion enrichment process.
  • the present invention relates to the first step in the method of manufacturing the barriers, and more precisely still, a step in the method of producing the supports which makes it possible to improve the efficiency of these barriers.
  • the present invention relates to a method which makes it possible, from a cylindrical tube and having a wall of regular shape, to modify this wall to create in it irregularities or imprints of determined shape.
  • These irregularities have the advantage, in the isotopic enrichment process, of creating turbulence in the gas circulating inside the tubes or barriers. Indeed, it has been found that, during the flow of the gas constituted by the isotopic mixture inside these tubes, there was a certain accumulation of one of the phases of the mixture on the internal surface of the tube. We understand that by creating this turbulence, we avoid this accumulation of one of the phases and we thus increase the separation coefficient by gas diffusion, that is to say the efficiency of the whole installation.
  • these cylindrical supports or tubes are produced using a ceramic composition which is formed using a die which thus defines the shape of the "support" tubes.
  • the die delivers at its outlet a tube whose wall has a regular thickness and the impressions are made on the wall of the tube immediately at the outlet of the die, that is to say at a point in the production line where the tubes are still relatively deformable.
  • these tubes or supports are produced from a paste which consists of a mixture of grains of the ceramic material which will subsequently be sintered and organic or mineral binders which give the paste a certain plasticity. Extrusion in the die takes place at an almost constant speed.
  • the tube as it leaves the die, is deformed by means of parts of suitable shape called knobs below, these parts being applied to the external wall of the tube, so as to push it in locally and thereby produce the irregularities of the desired shape defined by the knobs.
  • knobs parts of suitable shape
  • these knurls are driven in a movement such that the relative speed of movement between a knurl and the tube is substantially zero.
  • these knobs accompany the tube in its movement of movement due to the extrusion.
  • the tube is dried and sintered to give the final "support”.
  • the method can be implemented according to two distinct modes.
  • a first mode the wheels are driven in a translational movement parallel to the axis of movement of the tube. This displacement occurs over a certain length which is linked to the active length of the wheel.
  • the wheels are animated by a movement which tends to apply them to the outer wall of the tube or to move them away. It is understood that thus the relative speed between the tube and the wheel constituting the tool capable of making the impression is substantially zero and that there is a definition of the impressions by adjacent successive steps. Of course, a rapid return is planned between two active phases.
  • the rollers are mounted on rotary wheels arranged around the tube, the axes of rotation being perpendicular to the axis of the tube.
  • the rollers are mounted idly on axes and it is the drive of the tube itself which causes the disks carrying the rollers to rotate.
  • a motor ensures the rotation of these wheels with a speed synchronized with the running speed of the tube, the wheels being in fact driven in rotation by the running of the tube, the or the motors being used only to compensate for friction.
  • the present invention also relates to implementation of devices of said p rocézier, in its various embodiments and its variants.
  • the present invention also relates to porous porous ceramic tubes which are provided with indentations projecting inside said tubes, the shape of these indentations being for example in accordance with those which are defined by the method and the delivery devices. in action.
  • These imprints can for example be annular or be located regularly on generators of said tubes.
  • the essential characteristic of the invention consists in the fact that the rollers are moved in synchronism with the tube so that no relative movement exists between the two, these rollers acting on the tube at its exit from the sector.
  • Figure 2 refers to the first embodiment in which the knobs are driven in a translational movement parallel to the axis of movement of the tube,
  • Figures 3 to 8 referring to the second embodiment in which the rollers are moved using circular wheels.
  • FIGs 2a to 2c there is shown schematically a first embodiment of the method.
  • the die 2 with its punch 4 from which comes out the tube 6 which is produced continuously in a ceramic paste, and in which the lengths corresponding to the desired length of the "supports" will be cut.
  • the tube is not yet rigid.
  • the fingerprinting device essentially consists of two jaws or knobs 8a and 8b arranged on either side of the tube 6 and whose respective active face 10a and 10b reproduces the profile of the fingerprints to be produced.
  • the jaws 8a and 8b are mounted by means of a displacement device bearing the general reference 12 and which allows on the one hand a synchronized movement of the two jaws in the directions D 1 and D 2 thus making it possible to obtain a reconciliation jaws or their spacing and on the other hand, a displacement of the set of jaws according to the direc tions F and F 'which are parallel to the axis of progression of the tube and in opposite directions (the direction F' corresponds to a rapid return).
  • the assembly 12 can be guided by rods 14a and 14b and include the displacement motor means.
  • the movable assembly 12 may include the knives 18a and 18b capable of cutting the continuous tube which leaves the die 2 when the desired length for the support has been reached.
  • FIG. 2a illustrates the different stages of the production of the imprints.
  • the jaws are in contact with the tube and an impression is thus produced, the length of which is equal to the length A of the jaws.
  • the movable assembly 12 moves the jaws with a length equal to D in the direction F.
  • the devices 16a and 16b are actuated to cause the jaws to move apart and bring them back to the initial position shown in FIG. 2c (displacement F '). It is understood that thus a set of continuous impressions is produced if the length of the active surface of the jaws is equal to the distance traveled by the tube during the duration of a complete cycle.
  • the displacement members in the direction F of the jaws have an amplitude corresponding to the length of the useful face which takes place at a speed equal to the speed of exit of the tube from the die and a rapid return movement (F ').
  • the method for making the imprints consists in mounting knurling wheels on wheels mounted on axes perpendicular to the axis of the tube.
  • the wheels there are two wheels 30a and 30b on the periphery of which are mounted knobs 32 distributed on the periphery of the wheels.
  • Each of the wheels is mounted idly around an axis perpendicular to the axis of the tube 6.
  • These axes bear the references 34a and 34b respectively.
  • the spacing of the axes is such that the desired impression depth is effectively obtained. It is understood that the rectilinear progression of the tube simultaneously causes a rotation along the arrows f and f 'of the two wheels. Consequently, the relative speed of the rollers relative to the tube is substantially zero.
  • the wheels are mounted on the axes by means of high quality bearings.
  • the two wheels 30a and 30b are integral with the shafts 34'a and 34'b.
  • the wheels 30a and 30b are driven in rotation using a motor 36 associated with a clutch device 38.
  • a motor torque is applied which compensates for the friction torque of the bearings in which the shafts 34'a and 34'b of the wheels are mounted, while leaving the wheels to rotate at the speed imposed by the scrolling of the tube.
  • the clutch device 38 allows this adaptation.
  • the wheels 32 on the wheels 30a and 30b are offset, so that one obtains on the tube 6 imprints also offset.
  • the cutting of the adequate length of the continuous tube to obtain the supports can be carried out using knives mobiles 42 arranged at the outlet of the die 2 or using knives 44 and 44 'which are mounted directly on the wheels 30a and 30'b.
  • FIG. 6 there can be four wheels regularly arranged around the tube, the axes being always perpendicular to the axis of the tube.
  • the knobs 32 associated with four wheels arranged at 90 ° from each other. It is understood that in this way an annular groove 40 can be produced in the tube 6.
  • FIGS. 7a and 7b illustrate an alternative embodiment using wheels which make it possible to obtain alternating imprints on the tube, these imprints being shown in perspective in FIG. 1.
  • the deformations applied to the tubes alternately give a elliptical section S 1 of major axis arranged in the direction XX ', a circular section C 1 , a second elliptical section S 2 of major axis parallel to the direction YY' (perpendicular to the direction XX '), a circular section C 2 and the cycle is repeated with an elliptical section S 1 .
  • the device essentially consists of four wheels bearing the references 501, 50 2 , 50 3 , 50 4 whose axes are orthogonal to the axis of travel of the tube 6.
  • the respective axes 521, 52 2 , etc ... on which are mounted the corresponding wheels are rotated in synchronism by means of bevel gear gears 54 and 54 '. All of these shafts can be rotated by the motor 58 and a set of pinions 60 connected to the output of the motor by a clutch system 62.
  • the wheels of the wheels diametrically opposite with respect to the tube that is that is to say for example wheels 50 1 and 503, on the one hand and wheels 50 2 and 50 4 on the other hand, are synchronized, that is to say that the knobs 32 of wheel 50 1 act in same time as the wheels on the wheel 50 3 .
  • a a half-step offset is introduced between the position of the wheel knobs 50 . and 50 3 with the position of the knobs 50 2 and 50 4 . It is understood that one thus obtains an alternating pinching of the tube which successively produces the deformations in the form of ellipse S and the deformations in the form of ellipse S 2 .
  • the wheels 50 can include knives such as 64.
  • the wheels must have a periphery exactly equal to the length of the tube to be produced.
  • the wheel shafts are mounted in bearings having the least possible friction, for example ball bearing bearings. Their speed of rotation is imposed by the passage of the tube between the four series of rollers, the motor 58 only serving to compensate for friction.
  • the inertia of the wheels is such that their movement is uniform even during a period when no wheel is in contact with the tube. It goes without saying that the motor 58 is not essential as has already been explained since it is the progression of the tube which causes the corresponding rotation of the wheels.
  • FIG 8 there is shown in more detail a possible form of wheel.
  • the wheel 32 is mounted on the wheel by means of an axis 70.
  • the wheels have a shape limited by a portion of toric surface whose radius of curvature R is slightly greater than the radius of the tube to be deformed.
  • the formation of fingerprints by alternating pinching is particularly advantageous in terms of the characteristics of the ceramic tube. Indeed, seen on a local scale, the only deformation imposed on the ceramic paste is a bending practically without shearing. We can judge the low amplitude of the shear by the fact that the circumference of the tube is not modified by pinching: it remains practically constant whatever the position along the axis of the tube of the cutting plane in which we the measure. This differs significantly from the case in which the tube is deformed using four knurls acting simultaneously to obtain an annular impression. This avoids causing defects which sometimes appear in the sintered part (cracks, cavities, etc.), in particular if these deformations are repeated due to the fatigue effect which results therefrom. It is an advantage to obtain the deformation of the impressions by a local deformation which remains minimal and which is applied only once. very important of this variant of the process.
  • the ceramic paste contains volatile binders, it tends to dry superficially and this hardening facilitates the formation of cracks in the event of deformation.
  • the fact of forming the imprints immediately upon leaving the die is an important advantage of the process which is the subject of the invention.
  • Imprints are formed by the alternating pinching method described above (FIGS. 7a and 7b) on a tube 6 of ceramic paste under the following conditions:
  • the fingerprinting device comprises four wheels carrying toroidal wheels.
  • the radius of curvature of the profile of the rollers (R in FIG. 8) is 15 mm.
  • the distance between the axes of two neighboring knurling wheels is 16 mm.
  • the groove bottoms of the rollers are inscribed inside a circle of 318.3mm in diameter, the circumference of which corresponds to the length of the tube, or the length of the pattern to be written on the tube is 1000 mm.
  • the distance between the axis of each wheel and the axis of the die is 168.5 mm, which means that when two knurls located on opposite wheels grip the tube passing in the plane of the axes of the wheels, the distance between their throat bottoms is 18.7 mm.
  • the distance between the outlet of the die and the plane of the wheel axles is 250 mm.
  • the wheels are driven by the scrolling movement of the tube.
  • the tube is cut to the length of 1000 mm by knives 64 placed on the wheels.
  • p 1 mm. This depth is shallower than the depth which was obtained transiently at the time of passage between the knobs. This is due to the elasticity of the ceramic paste, which means that a momentary deformation is not fully preserved.
  • the wheels are driven by an electric motor 58 whose movement is transmitted to them by an electromagnetic clutch 62 which makes it possible to adjust the applied torque.
  • the speed of rotation of the motor is adjusted to 12 rpm, which corresponds to a peripheral speed of the knobs equal to the speed of extrusion of the tube, ie 200 mm / s.
  • the torque transmitted by the clutch is adjusted so as to exactly compensate for the friction torque of the bearings of the wheel axles.
  • the cutting of the tube is not ensured by knives fixed on the wheels, but by knives located between the die and the wheels (see Figure 3) and actuated by electromagnets (not shown).
  • electromagnets are powered by a relay which is triggered by an electromagnetic proximity sensor which sends a pulse to the relay each time a small magnetic mass fixed on one of the wheels passes near it.
  • This device ensures the sectioning of the tube at each turn of the wheel, to the length of 1000 mm corresponding to the periphery of the wheels measured at the level of the groove bottoms of the rollers.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical & Material Sciences (AREA)
  • Ceramic Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Rigid Pipes And Flexible Pipes (AREA)
  • Devices For Post-Treatments, Processing, Supply, Discharge, And Other Processes (AREA)
EP82401224A 1982-06-30 1982-06-30 Verfahren und Vorrichtung zum Formen von Eindrücken auf keramische Rohre Withdrawn EP0097750A3 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP82401224A EP0097750A3 (de) 1982-06-30 1982-06-30 Verfahren und Vorrichtung zum Formen von Eindrücken auf keramische Rohre

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP82401224A EP0097750A3 (de) 1982-06-30 1982-06-30 Verfahren und Vorrichtung zum Formen von Eindrücken auf keramische Rohre

Publications (2)

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EP0097750A2 true EP0097750A2 (de) 1984-01-11
EP0097750A3 EP0097750A3 (de) 1984-05-09

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EP82401224A Withdrawn EP0097750A3 (de) 1982-06-30 1982-06-30 Verfahren und Vorrichtung zum Formen von Eindrücken auf keramische Rohre

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1990013405A1 (de) * 1989-05-11 1990-11-15 Hoechst Ceramtec Aktiengesellschaft Aluminiumoxidrohre und verfahren zu ihrer herstellung
WO2014167506A1 (en) * 2013-04-10 2014-10-16 Council Of Scientific & Industrial Research Flow reactor with pinched pipe sections for mixing and heat transfer
CZ305938B6 (cs) * 2012-10-10 2016-05-11 Milan KubĂ­n Tvářecí zařízení

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1150246A (fr) * 1955-05-27 1958-01-09 Perfectionnements apportés aux appareils pour la fabrication de corps tubulaires présentant un rétreint
NL261944A (de) * 1960-03-05
US3242828A (en) * 1963-12-19 1966-03-29 Jay Dee Products Co Inc Apparatus for use in the manufacture of sipping straws and the like, and other tubular products
US3184793A (en) * 1964-04-03 1965-05-25 Roger P Plourde Apparatus for producing a continuous tubular article
FR2503616A1 (fr) * 1978-11-27 1982-10-15 Commissariat Energie Atomique Procede et dispositif de formation d'empreintes sur des tubes en ceramique

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1990013405A1 (de) * 1989-05-11 1990-11-15 Hoechst Ceramtec Aktiengesellschaft Aluminiumoxidrohre und verfahren zu ihrer herstellung
AU639926B2 (en) * 1989-05-11 1993-08-12 Degussa A.G. Aluminium oxide tubes and process for manufacturing them
CZ305938B6 (cs) * 2012-10-10 2016-05-11 Milan KubĂ­n Tvářecí zařízení
EP2719477A3 (de) * 2012-10-10 2016-09-07 Milan Kubin Vorrichtung zum Umformen von Wärmetauscherrohre
WO2014167506A1 (en) * 2013-04-10 2014-10-16 Council Of Scientific & Industrial Research Flow reactor with pinched pipe sections for mixing and heat transfer

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Publication number Publication date
EP0097750A3 (de) 1984-05-09

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Inventor name: GILLOT, JACQUES