FR2894871A1 - DEVICE FOR SHAPING COMPACTABLE MATERIAL AND METHOD OF USING THE DEVICE - Google Patents

Abstract

The invention relates to a device (1) for forming a support material (4) with a tapered bore with an axis (X'X), housing two conical shells (3a, 3b) fitting into said bore and comprising a cylindrical bore according to (X'X), adapted to accommodate two cylindrical shells (2a, 2b) fitting into said cylindrical bore (16, 17; 16 ', 17'), said cylindrical shells (2a, 2b) once tightened comprising a cylindrical through bore according to (X'X), a cavity adapted to receive a compactable material being formed of spaces respectively formed in the conical and cylindrical shells (2a, 2b, 3a, 3b) when the cylindrical shells (2a, 2b) are clamped in the cylindrical bore, the through bore being adapted to receive a piston (6) under pressure on said material, the shape of the piston head (6) and the cavity determining the shape (7) of the compacted material.

Description

DEVICE FOR SHAPING COMPACTABLE MATERIAL AND METHOD

  The invention relates to a device for shaping a compactable material, in particular a spherical body, and a method of using the device. The manufacture of pellets or beads from compactable material is known and widely used in the industrial field, particularly in the field of the pharmaceutical industry, when the compactable material is mixed with another product, most often in liquid aqueous phase , so as to form a more or less pasty body. But the manufacture of pellets or beads from dry compactable material raises much more difficulty in other industries, such as in the nuclear industry, where environmental and / or safety conditions prohibit the use of a other product in aqueous liquid phase. It is indeed delicate to press a compactable material into a matrix when it is composed from particulate matter, especially when the shape to be obtained is a sphere. In the field of the nuclear industry, pellets of dry compactable geometry material having a revolution axis can be obtained by using a uniaxial press with one or two pins, but the standard dies are not usable for manufacturing. spheres directly from powders. Currently, only liquid chemical and / or sol-gel methods are used to obtain spherical bodies. It remains, therefore, to form an effective method for producing spherical body shaping from a dry material. By dry is meant here substantially free of product in the liquid phase. The invention aims to remedy this problem by proposing a device for shaping compactable material, particularly adapted to the shaping of spherical body, the device being particularly easy to use. For this purpose, the object of the invention relates to a device for shaping compactable material, in particular spherical body, comprising a liner support A. substantially conical bore of a given axis and a large base on a so-called surface surface working, adapted to house at least two substantially conical shells

  complementary to said conical boring and interlocking tightly against each other in said bore, said two tapered shells, when clamped against each other, having at least one substantially cylindrical bore in their working surface portion and substantially axially along said axis, adapted to accommodate at least two substantially cylindrical shells complementary to said cylindrical bore and interlocking tightly against each other in said bore, said cylindrical shells being clamped together against the other having a bore traversing substantially cylindrical and substantially axial along said axis, the conical shells and cylindrical shells being such that, when the cylindrical shells are pressed against one another in the cylindrical range, a cavity adapted to receive a compactable material is present, formed spaces respectively formed in the conical and cylindrical shells, the opposite side to the surface The shape of the workpiece, and the passageway therethrough for receiving a piston in pressure on said material, the shape of the piston head and the cavity determining the shape of the compact material. In a particularly preferred embodiment, the piston head is substantially hollow shaped spherical cap and the shape is substantially spherical. The two conical shells generally fit into most of the conical bearing, from the work surface side. The two cylindrical shells generally fit most, preferably all, of the cylindrical extension from the work surface side. Preferably, the device further comprises at least one holding element and / or at least one element for facing the conical shells with respect to each other. Such a maintenance and / or such a look-up generally corresponds to the oil position. said shells are tight against each other for interlocking. An element can have both a hold function and a lookup function. The holding members generally have a clamping function, and are therefore generally clamping members. The holding elements are generally also elements usable in facing, and are more particularly used for machining, usually without further use for shaping. These are, for example, screw holes

  mirror each of at least one threaded portion for a screw to be inserted and tightened therein. In the context of the invention, it is for example possible that two transverse planes of the two conical shells, in the interlocked position against each other for interlocking, each comprise two holes for screws parallel to each other, passing through the solid parts of both shells, and arranged head-beaks. An interleaving element advantageously allows the two conical shells to be held relative to one another before they are interlocked, generally simultaneously, in the liner. These are, for example, holes for pins. According to a preferred embodiment of the invention, the device is such that the two cylindrical shells snugly fit into said conical bore, substantially flush with the working surface of said conical shells. Thus, the pressure, which is reviewed on the working surface of the cylindrical shells and on the conical shells, is also advantageously distributed over the surfaces of these shells. According to a preferred embodiment of the invention, the device is such that the piston is adapted to fit into said through bore, substantially flush with the working surface dimension surface of said cylindrical shells. This advantageously makes it possible to produce the desired shape, for example a sphere, flush with said surface. Thus, it is possible to reduce the risk of over-pressing the compactable material once the shaping obtained, that is to say that, when the piston is flush, the pressure which is reviewed work surface side to insert then push the piston into the device, is supported at least by the cylindrical shells and not by the piston. This protects very advantageously the compact material. This pressure is also, in a particularly advantageous embodiment, supported both by the cylindrical shells and the conical shells if the two cylindrical shells fit snugly against one another in said cylindrical bore, substantially outcrop of the working surface of conical shells. In an even more advantageous embodiment, when all surface surfaces working surface are coplanar, this pressure is supported by cylindrical shells, conical shells and the jacket.

  In any case, the state of the working surface surfaces is such that these surfaces must avoid maximizing the retention of compactable material, if it is poured onto one of these surfaces. A simple leveling, for example manual, must allow to avoid the excess of compactable material which would be poured by megarde on one of these surfaces. Preferably, the set of cylindrical shells, when clamped against each other, has an axial symmetry along said axis, or the set of conical shells, when clamped against each other, has an axial symmetry along said axis. Particularly preferably, all of the cylindrical shells, when clamped against each other, have an axial symmetry along said axis, and the set of conical shells, when clamped against each other, have an axial symmetry along the axis. said axis.

  The invention also relates to a process for shaping compactable material by using a device according to the invention, as the following successive steps are carried out: 1) the device is put in place, by interlocking the conical shells , possibly held together and / or clamped against each other in the jacket, then by interlocking cylindrical shells in the conical shells, the axis being preferably substantially vertical, 2) the compactable material is introduced into the cavity from the working surface, preferably by gravity; 3) a piston is introduced into the substantially cylindrical through-gap, to exert pressure on the compactable material so as to compact it substantially in the desired shape. Preferably, the method according to the invention is such that, the piston being able to fit into said through bore substantially flush with the working surface surface area of said cylindrical shells, the end of the forming process is determined by said outcrop. It is a very advantageous benefit of the method according to the invention to allow forming in one step, step 3), during which a compactable material is passed to a shape, preferably a sphere, compacted. In a particularly preferred manner according to the invention, the compactable material is a powder or particulate material, if appropriate.

  mixture A. at least one binder. For the purposes of the present invention, the term "powder" is intended to mean a set of particles whose dimensions are usually less than 1 millimeter. The use of a material of greater particle size is however possible according to the invention, by making bodies, for example spherical, larger diameters than for a finer particle size. According to a particularly advantageous implementation of the method according to the invention, the shaping is carried out by the mass of material to be compacted.

  The invention is particularly directed to the case where the compactable material is dry, and the desired shape is substantially a sphere or spherical body, in which case no solution exists in the prior art. In addition, one of the advantages of the method of the invention is that the demolding of the embodiment is particularly comfortable. The invention is now described with reference to the accompanying nonlimiting drawings, in which: - Figure 1 is a schematic sectional view of a device according to the invention, before assembly; - Figure 2 is a schematic sectional view of the device of Figure 1, after assembly; FIG. 3 is a schematic view of a partial variant of the device of the invention; - Figure 4 is a schematic sectional view of the variant of Figure 3; - Figure 5 is a schematic view of a section of the variant of Figure 3; and FIG. 6 is a schematic view of a section of the variant of FIG. 3; FIG. 7 is a photographic reproduction of two spheres made according to the invention, and FIG. 8 is a photographic reproduction of two spheres made. according to the invention.

  Figure 1 is a schematic sectional view of a device 1 according to the invention, before assembly. Figure 2 is a schematic sectional view of the device 1, after assembly. In these

  figures, the compactable material has not been represented. The device 1 comprises a support forming a liner 4 having a conical bore 14 of axis (X'X) and a large base on a surface 28 called working surface. The bore 14 is able to accommodate two conical shells 3a and 3b, complementary to said conical bore 14 and interlocking tightly one 3a against the other 3b in said bore 14. There remains a small space in part lower side Figures 1 and 2, not filled by said shells 3a and 3b conical. This space advantageously ensures that the tapered shells are well positioned (good conical nesting and good tightening of the shells between them). The shells 3a and 3b once nested have their working surface portion 28 (which is here the upper side of Figures 1 and 2) a cylindrical bore (16, 17) axial axis 1 (X'X). The cylindrical bore (16, 17) is formed of two similar parts and, according to a preferred shaping of the invention presented in this embodiment, in a mirror of the other. These are the parts 16, semi-cylindrical bore of the shell 3a, and 17, semi-cylindrical bore of the shell 3b. Said bore (16, 17) is adapted to accommodate two cylindrical shells 2a and 2b, complementary to said conical bore (16, 17) and interlocking tightly against each other in said bore (16, 17). The cylindrical shells 2a and 2b, when clamped against each other, have a cylindrical (29, 30) axial through bore (X'X). The cylindrical through bore (29, 30) is formed of two similar parts and, in a preferred shaping of the invention presented in this embodiment, mirrored against the other. These are the parts 29, semi-cylindrical through bore of the shell 2a, and 30, semi-cylindrical through bore of the shell 2b. The conical shells 3a and 3b and the cylindrical shells 2a and 2b are such that when the cylindrical shells 2a and 2b are pressed against one another in the cylindrical bearing (16, 17) (see FIG. 2), a cavity is presented, formed spaces 10, 11, 12, 13 respectively formed in the shells 2a, 2b, 3a and 3b. This cavity 10-13 is formed on the opposite side A. the working surface 28. Elie is present in the part in which said shells 2a, 2b, 3a and 3b are opposite (see Figure 2).

  The cavity 10-13 is of course adapted to receive a compactable material. The through bore (29, 30) of the cylindrical shells 2a and 2b is intended to A. receive a piston 6 under pressure on said material. The form

  of the piston head 31 is a spherical cap. The cavity 10-13 and the piston head 31 determine the shape 7 of the material to be compacted. In this embodiment, the shape is a sphere 7. In the embodiment of Figures 1 and 2, the upper surfaces 32 of the conical shells and cylindrical shells are flush. In addition, the piston 6 is such that, once nested, its upper surface is flush with said surfaces 28 and 32. This also means that the pressure transmitted to the material to be compacted is not higher than the pressure necessary for the piston 6 is nested. Any pressure higher than said required pressure, for example transmitted by a hydraulic type press, is exerted on the surfaces 28 and 32 and not on the piston 6. This advantageously makes it possible not to overwork the material once compacted, and therefore to avoid weakening or even breaking it. This is an advantage over prior art devices in which the compacting is carried out by the pressure exerted. In the execution of the invention, the compaction is thus managed mainly by the mass of material to be compacted. Figure 3 is a schematic view of a partial variant of the device of the invention. In this variant, the two conical shells 3a and 3b of the device 1 of FIGS. 1 and 2 have been replaced by conical shells 3'a and 3'b, which comprise holding and facing means. The shells 3'a and 3'b respectively define half-cylindrical bores 16 'and 17', and spaces 12 'and 13' intended to form a cavity. The shells 3'a and 3'b may form a device 1 'according to the invention, in combination with the liner 4 and the cylindrical shells 2a and 2b. Sections IV-IV, V-V and VI-VI, respectively shown in Figures 4, and 5 and 6, complete Figure 3 for this execution. Figure 5 shows, in a transverse plane, two holes 18 and 19 for pins. The insertion of two pins (not shown) allows the facing of the two conical shells 3'a and 3'b. Figure 6 shows two screw holes: 26 and its threaded portion 22, and 27 and its threaded portion 23. These holes are all parallel to each other and through the solid parts of the two shells in head-to-head Fun the other, that is to say that the hole (26,22) is in head-beak position relative to the hole (27, 23). FIG. 4 shows two screw holes 21 and its threaded portion 20, 25 and its threaded portion 24. These holes are all

  parallel to each other and passing through the solid portions of the two shells in the head-to-head position of the other, that is to say that the hole (21, 20) is in the head-to-head position relative to the hole (25,24). In this embodiment, these holes (21, 20; 25, 24; 26, 22; 27, 23) are means for holding the conical shells in a tight position relative to each other, which are advantageously used during machining to allow very precise machining. But it is possible according to the invention to have another device in which the holding means are not present, the machining then being performed differently, and the means of facing (18,19) being alone present. Figures 7 and 8 are explained below in the examples of implementation.

  EXAMPLES OF IMPLEMENTATION It was used a device 1 according to the invention, for compacting dry particulate material, for which all parts were made of stainless steel type 316, and the punch or piston used was Z160CDU12 steel (after treatment thermal 60HRC). The dimensions of the pieces were, for a spherical shape of 3, 4 mm in diameter. • For the jacket, an external cylindrical shape with a height of 60 mm and a diameter of 70 mm, and a conical bore of large base (surface dimension of working) of 45 mm, a conical boring depth of 60 mm, and a conic angle of 7; • For the two tapered half-shells, a height of 58 mm, a diameter of large base (working surface dimension) of 45 mm, a cylindrical boring depth of 15.8 mm, and a cylindrical boring diameter of 15 mm. mm, and a spherical portion space of diameter 1.7 mm household in all of these shells; • For the two cylindrical half-shells, a length of 15.8 mm, and a spherical portion space of diameter 1.7 mm household in all of these shells; • For the piston a length of 15.8mm for a diameter of 3mm, a hollow shell for sphere of 3.4 mm being end-shaped.

  Devices in which the diameters of the spherical shapes (matrices) made were respectively 3.4 mm and 1 mm were valid. Tests of titanium nitride powder have been conclusive for these two diameters.

  FIG. 7 is a photographic reproduction of two titanium nitride spheres made according to the invention, in spherical dies of 1 mm and 3.4 mm in respective diameters.

  In the context of the use of a single device for producing UPuN and UPuC combustible material spheres, eight conclusive tests have also been carried out for spherical shapes with a diameter of 2.7 mm.

  For the production of UPuN fuel material spheres, these tests are given below in the Table, which shows the measurements made on UPuN after a densification treatment. Mass D1 D2 D3 D4 Diameter Volume MVG MVG / (g) (mm) (mm) (mm) (mm) average (mm3) (g.cm-MVTh (mm) 3) (%) 1 0.091 2,431 2,404 2,431 2,393 2 , 41 7.37 12.34 86 2 0.090 2.408 2.393 2.425 2.399 2.40 7.27 12.38 86 3 0.091 2.418 2.417 2, 432 2.420 2.42 7.44 12.24 85 4 0.087 2.369 2.39 2.385 2.408 2 , 40 7,21 12.07 84 5 0.083 2,414 2,338 2,327 2,315 2,35 6.78 12.24 85 6 0.092 2,423 2,419 2,420 2,423 2,42 7.43 12.38 86 7 0.092 2,391 2,395 2,481 2,448 2.43 7,50 12,26 86 8 0,092 2,453 2,435 2,439 2,487 2,45 7,73 11,90 83 Or: MVG: Geometric Density and DTh: Density 20 Theoretical. Spheres thus formed showed shrinkage at shaping (spheres obtained about 2.3 to 2.5 mm in diameter) for this UPuN material. The tests thus carried out were found to be conclusive because the forming process was easy to carry out and provided very little scrap. In addition, the size dispersion was very low, the sphericity was good and the spheres obtained after shaping were of good mechanical strength. FIG. 8 is a photographic reproduction of two spheres made according to the invention, in the same spherical matrix 2.7 mm in diameter.

Claims (10)

  1. Device (1, 1 ') for shaping compactable material, in particular spherical body, comprising a liner support (4) with substantially conical bore (14) of axis (X'X) gives and large base on a surface (28) said working surface, adapted to accommodate at least two substantially conical shells (3a, 3b, 3'a, 3'b) complementary to said conical boring (14) and interlocking tightly against the other in said bore (14), said two tapered shells (3a, 313; 3'a, 3'b) when tightened against each other having in their work surface side portion (28) at least one bore substantially cylindrical (16, 17; 16 ', 17') and substantially axial along said axis (X'X), able to accommodate at least two substantially cylindrical shells (2a, 2b) complementary to said cylindrical bore (16, 17; 16 ', 17 ') and interlocking tightly against one another in said bore (16, 17; 16', 17 '), said cylindrical shells (2a, 2b) once tightened against each other. The other having a substantially cylindrical through-bore (29, 30) and substantially axial along said axis (X'X), the conical shells (3a, 3b; 3'a, 3'b) and the cylindrical shells being such that when the cylindrical shells (2a, 2b) are clamped against each other in the cylindrical bore (16, 17 ', 16', 17) a cavity (10-13) adapted to receive a compactable material is provided, formed respectively by spaces in the conical and cylindrical shells (2a, 2b, 3a, 3b) on the opposite side to the working surface (28). and the recess (29, 30) therethrough for receiving a piston (6) under pressure on said material, the shape of the head (31) of the piston (6) and the cavity (10-13) defining the shape (7) of the compact material.   2. Device (1, 1 ') according to the preceding claim such that the piston head (31) is substantially recessed spherical cap, and the shape (7) is substantially spherical.   3. Device (1, 1 ') according to rune preceding claims further comprising at least one holding member (20-27) and / or at least one setting element (18, 19) conical shells (3') a, 3'b) relative to each other.   4. Device (1, 1 ') according to one of the preceding claims such that the two cylindrical shells (2a, 2b) fit snugly against one another in said conical bore (16, 17; 16', 17 ' ), substantially flush (32) of the working surface (28) of said conical shells (3a, 3b, 3'a, 3'b).   5. Device (1, 1 ') according to rune preceding claims such that the piston (6) is adapted to fit into said through bore (29, 30), substantially flush with the surface (32) dimension work surface (28) said cylindrical shells (2a, 2b).   6. Device (1, 1 ') according to one of the preceding claims such that the set of cylindrical shells (2a, 2b) once tightened rune against each other has an axial symmetry along said axis (X', X) and / or the set of conical shells (3a, 3b; 3'a, 3'b) when clamped against each other has an axial symmetry along said axis (X ', X).   7. Process for shaping compactable material by use of a device (1, 1 ') according to one of the preceding claims, as the following successive steps are carried out: 1) the device (1, 1') ) is put in place, by interlocking the conical shells (3a, 3b), possibly held and / or tightened rune against the other, in the jacket (4), then by interlocking cylindrical shells (2a, 2b) in the shells conical (3a, 3b), the axis (X ', X) being preferably substantially vertical, 2) the compactable material is introduced into the cavity (10-13) from the working surface (28), preferably 3) a piston (6) is introduced into the substantially cylindrical through-gap (29, 30) to exert pressure on the compactable material to substantially compact it in the desired shape (7).   8. Method of shaping compactable material according to the preceding claim, such that, the piston (6) being adapted to fit into said through bore (29, 30) substantially flush with the surface (32) surface area of working (28) said cylindrical shells (2a, 2b), the end of the shaping process is determined by said outcropping.   9. Process for shaping compactable material according to one of claims 7 or 8, such that the compactable material is a powder.   10. Process for shaping compactable material according to one of claims 7 to 9 in which the shaping is carried out by the mass of material to be compacted.