US3135995A - Method of and apparatus for the generation of pressure inside an enclosed cavity - Google Patents

Description

June 9, 1964 c. BALLHAUSEN 3,135,995 METHOD OF AND APPARATUS FOR THE GENERATION 0F PRESSURE INSIDE AN ENCLOSED CAVITY Filed March 1, 1961 2 Sheets-Sheet 1 FIGJ F 4 CARL BALLHAUSEN BYZMMQI @MZfiVW ATTQRNEW SEN THE GENERATION ENCLOSED CAVITY June 9, 1964 Q BALLH METHOD OF AND APPARATUS PRESSURE INSIDE AN Filed March 1, 1961 lNVENlOR All FIG.8

ATTORNEYS United States Patent 3,135,995 7 METHOD OF AND APPARATUS FOR THE GEN- ERATION 0F PRESSURE INSIDE AN ENCLOSED CAVITY Carl Ballhausen, 19 Neusserstrasse, Krefeld, Germany Filed Mar. 1, 1961, Ser. No. 92,624 I Claims priority, application Germany Mar. 2, 1960 9 Claims. (Cl. 18-16) The present invention relates to a method of and a device for generating omnidirectional high pressures i.e., pressures from all sides, on a substance in an enclosed cavity. The present invention envisages more especially the generation of pressures in the neighbourhood of 400 kg./sq. mm. and more. Such high pressures are required for instance for the conversion of certain thermodynamically stable modifications of substances into thermodynamically unstable modifications. The principal interest in this connection centres upon the production of diamonds by submitting graphite to a pressure and temperature treatment.

According to my copending application filed March 3, 1960, Serial No. 15,383, now Patent No. 3,084,388, one method is proposed which consists in compressing within adie a cartridge made of a plastically deformable material, one end of which cartridge initially projects from I the die. The internal capacity (cavity) of the cartridge is thus reduced and a considerable omnidirectional in crease in pressure is thus generated on the substance inside the cavity. This may be effected whilst the substance is heated, e.g., electrically, as indicated in my aforesaid application. According to the saidapplication, the pressure is applied in the direction to compress-the plastically deformable cartridge axially. Under this pressure the material of the cartridge yields inwards in a direction normal to the line of action ofthe appliedforce, causing a reduction in the internal capacity of the cartridge which at the same time presses against the walls'of the die surrounding the cartridge and causes a certain amount of deformation also of the walls of the die. By appropriate construction of the die and by suitably selecting the material of the die this deformation can be kept within the load-carrying capacityof the material of the die. A

It has now been recognized, in accordance with this invention that a further considerable increase in pres sure inside the plastically deformable cartridge can be achieved by applying acompressive force to the die in addition to the application of the compressive force to the cartridge and codirectionally therewith. This can be done by generating the compressive force employed for deforming the cartridge and the codirectional compressive force which acts on the die by means of the same ram or pair of associated rams. In such a case the procedure consists in allowing a ram which has a greater diameter than the plastically deformable cartridge first to deform the cartridge and then to act on .the die. Nevertheless, the compressive force applied to the cartridge may be applied by one ram and the compressive force applied to the die by a separate ram. For instance two concentrically telescoped rams may be used, the two forces being applied simultaneously or consecutively in predetermined sequence.

It is therefore the principal object of this invention to provide an improved method and apparatus for generating high all-around pressure to a substance by deformation of a deformable metallic cartridge containing the substance by compressing not only the cartridge fully into a die cavity with ram means but also to compress the die in the same direction as the cartridge, at least in the region surrounding the die cavity and without requiring the ram means to enter the cavity.

3,135,995 Patented June 9, 1964.

Other objects and advantages of this invention will become apparent to one of ordinary skill in the art after reading the appended claims, and the following detailed description of various embodiments of the invention, in conjunction with the attached drawings, wherein:

FIGURE 1 is a sectional elevation of one embodiment; and

FIGURES 2, 3, 4, 5, 6, 7 and 8 are similar views each showing a further different embodiment.

The compressive force acting on the die as above mentioned, may be applied either directly to the die or at least to the parts of the die which directly surround the plastically deformable cartridge, or the said force may be transmitted through a layer of plastically deformable material which is more or less hardenable under stress and which is interposed between parts of the die and the ram. I

I For concentrating the pressure generated by the. deformation of the walls of the die to the immediate surroundings of the cartridge and in the direction of the axis thereof it is proposed to form one or both of the opposed faces of the die in such a way that their shape is at least approximately spheroidal or paraboloidal. It is not essential that the faces of the die which are thus shaped should define the said surfaces in the form of continuous surfaces in the mathematical sense. The surfaces may in fact be discontinuous that is to say stepped or similarly formed. Moreover, instead of a spheroidal or paraboloidal conformation of the die faces, it has also been found advantageous if one or both faces of the die slope towards the outer periphery and define a cone-shaped configuration. Again the surface .may be continuous, or discontinuous, i.e. stepped.

As has been mentioned, the compressive force applied to the die may be either directly applied or transmitted thereto through an interposed plastically deformable more or less stress hardenable material placed between die and ram. The inter-position of a plastically deformable material of this kind causes the pressure to be transmitted simultaneously to the whole of the face of the die when the latter is cambered or curved. However, in coni v formity with the relative deformation ofthe interposed material the specific pressure will then decrease towards the outside. Moreover, under the effect of the pressure the interposed material begins to flow radially outwards towards the edge of the die. The friction which is thus engendered tends to expand the die radially outwards. In, order to. prevent this effect it is further proposed to provide an interposed layer, not in the formof a disc ring, but in the form of concentric rings or in the form of a spiral. In the course of the deformation of an intermediate layer of this kind, the interposed material will flow both towards the inside of the die as well as towards the edge of the die, and consequently the resultant frictional forces will act in contrary directions and thus cancel each other out.

For improving the adhesion of the'intermediate layer, especially if this is in the form of a spirally coiled wire, it has been found advisable slightly to roughen the faces of the die. Moreover the face of the ram may be treated in a similar way.

Especially when use is made of an intermediate layer in the form of a double spiral or rings the gaps between neighbouring convolutions of the coiled wire or between the rings may be used to provide a spiral path or medium for cooling the device during the process of pressing.

, Cooling may be provided, for instance, by conducting 3 ing drawings which schematically represent devices the kind herein described.

FIG. 1 shows the upper part 1 of a compression die which, as indicated in my aforesaid application, consists of rings of material of different strengths and, if desired, also of different compositions. The drawing shows that the rings are slightly coned. This conicity is required to permit the rings to be pressed together. If it is desired to shrink them together cylindrical rings may be used. The plastically deformable cartridge, of the type for example referred to in FIGURES 3-5 of my aforesaid application, is indicated at 2 and, in its interior, provides the compression cavity. At 3 this plastically deformable cartridge projects slightly beyond the upper end face of the die 1. 4 represents the ram which in the drawing applies the pressure required for the plastic deformation of the cartridge 2 as well as the compressive force which acts on the die in the direction indicated by arrows 5. As fully described in my aforesaid Patent 3,084,388, the projecting end 3 of the cartridge is forced by relative movement of the die and ram towards each other so as to be compressed within the cavity whereby the upper surface of the cartridge lies substantially solely within the die due to the compression elfected by ram 4. The ram 4 is'likewise surrounded by rings which contain the ram and increase its resistance in the direction normal to the pressing direction.

It will be seen at 6 that the end face of the die has a continuous paraboloidal (or possibly spheroidal) shape. In the modification, FIGURE 2, the shape of the end face of the die at 7 is similar but the curvature extends not across the entire width of the ring area of the said face but across about only half that width. At 8 it will be seen that the rings which surround the ram may likewise be shaped to define a similar end face rings area or surface. This, on the one hand, increases the lateral load-supporting capacity of the ram and, on the other, provides more clearance for the interposition of the afore-mentioned plastically deformable intermediate layers between ram and die.

Similarly to the die in my above mentioned patent, the central element which forms the cavity of the die herein, as well as the other rings which surround that central ring, may be made, for instance, of a steel which which has been submitted to a previous thermal treatment or which has been cold worked in such manner that the rings have increasing strength progressively to the inside, whereby the outer ring has the lowest mechanical strength and the inner or central ring is the strongest. Likewise cartridge 2 may be similar to the cartridge described in detail in that prior patent of mine, though any other cartridge may be employed as long as it has at least one end which projects from the die as above described.

FIG. 3 is a similar embodiment to that of FIG. 1,

the only difference being that the end face 9 of the die is shown to slope away in the form of a shallow central cone. In the modified embodiment, FIG. 4, the end face 10 of the die is radially stepped by the separate rings.

In the embodiment shown in FIG. an intermediate flat disc ring 11 is interposed between the upper end face of the die 12 and the opposing lower end face of the ram 13 and its surrounding rings 14. The surfaces of the ring are suitably shaped to conform with the surfaces of the die and of the ram and its rings.

Instead of providing an interposed layer of plastically deformable stress-hardenable material in the form of a flat disc-shaped ring 11, a series of co-axial wire rings as indicated at 15, in FIGURE 6, may be interposed between the opposed faces of the die and ram and the rings thereof. The wires in this embodiment are of rectangular cross-section and of changing dimension as illustrated. The rings, may be of circular cross-section as shown in the embodiment according to 'FIG. 7, the rings 16 being of progressively greater diameter in the outward direction. FIG. 8 shows a form in which the rings 17 are of substantially triangular cross section. The wires may however be of any suitable cross-sectional contour.

Substances suitable for treatment by the present method and suitable materials for the compressible cartridge are described in the aforesaid application and other features described therein are applicable to the present method. The plastically deformable rings herein before referred to may be of an austenitic steel with a content of about 17% chromium and 7% nickel. For obtaining diamond from graphite a suitable ram pressure is 100,000 kg./sq. mm.

What I claim is:

1. A method of generating high all-round pressure to a substance by deformation of a deformable metallic cartridge containing the said substance, which comprises arranging the said metallic cartridge containing the said substance in a cavity in a die with opposed end faces '50 that an end portion of the cartridge projects beyond at least one said end face of the die, compressing the cartridge by means of an opposing member while maintaining the said member outside the said cavity to compress said cartridge end portion substantially solely within the die, and, at least by the time when the said cartridge end portion has been brought within the said cavity, causing the said opposing member to apply compressive force to the die itself co-directionally with the direction in which it applies compressive force to the cartridge to deform the die around the said cavity to increase the load supporting capacity of the die.

2. A method of generating high all-round pressure to a substance by deformation of a deformable metallic cartridge containing the said substance, which comprises arranging the said metallic cartridge containing the said substance in a cavity of a die having a member forming a die cavity and surrounded by concentric hard metallic rings, so that the end portion of the cartridge projects beyond the end face of the said member forming the said cavity, compressing the cartridge by means of an opposing member comprised of a central plunger and surrounding reinforcing rings while maintaining the said plunger outside the said cavity so that said cartridge end portion lies solely within the said cavity, and, at least when the said cartridge end portion has been brought within the said cavity, causing the plunger and rings of the said opposing member to apply compressive force to the cavity forming member and said rings of the die co-directionally with the direction in which the plunger applies its compressive force to the cartridge.

3. The method according to claim 2 in which compressive force is applied progressively to the outer regions of the die and in the same direction as the direction of compression of the cartridge after initially compressively stressing the die in the region of the said cavity-forming member and immediately surrounding the die cavity.

4. The method according to claim 2 including transmitting the said co-directional compressive force to the said cavity forming member and said rings of the die through the medium of plastically deformable stresshardenable material interposed between the corresponding end face of the die and said opposing member.

5. Apparatus for generating high all-round pressure in the interior of a metallic cartridge containing a substance that is to be compressed, comprising a die comprised of a central component providing a cavity for the said cartridge and surrounding reinforcing rings, said die being adapted to receive the cartridge with an end portion projecting from an end face of the said central component, at least one opposed means comprised of a central plunger and surrounding reinforcing rings for causing the plunger, without entering the said cavity, to apply compressive force to the cartridge to compress the cartridge wholly within the cavity and means to apply compressive forces to the central component and rings of the die in the same 5. direction as the plunger applies its compressive force to the cartridge to deform the die around the said cavity and increase the load supporting capacity of the die.

6. Apparatus for generating high all-round pressure in the interior of a metallic cartridge containing a substance that is to be compressed, comprising a die comprised of a central component providing a cavity for the said cartridge and surrounding reinforcing rings, said die being adapted to receive the cartridge with an end portion projecting from an end face of the said central component, means including at least one opposed means comprised of a central plunger and surrounding reinforcing rings for causing the plunger, without entering the said cavity, to apply compressive force to the cartridge to compress the cartridge wholly within the cavity and to apply compressive forces to the central component and rings of the die in the same direction as the plunger applies its compressive force to the cartridge to deform the die around the said cavity and increase the load supporting capacity of the die, in which said central component of the die has its end face nearer to the opposed face of the plunger of the opposing member than the corresponding end faces of the rings of the die are to the opposed end faces of the rings of the opposing member so that the opposing member can concentrate pressure of compression in the central component of the die and then apply pressure to the successive rings of the die surrounding the said central component.

7. Apparatus for generating high all-round pressure in the interior of a metallic cartridge containing a substance that is to be compressed, comprising a die comprised of a central component providing a cavity for the said cartridge and surrounding reinforcing rings, said die being adapted to receive the cartridge with an end portion projecting from an end'face of the said central component, means including at least one opposed means comprised of a central plunger and surrounding reinforcing rings for causing the plunger, Without entering the said cavity, to apply compressive force to the cartridge to compress the cartridge wholly within the cavity and to apply compressive forces to the central component and rings of the die in the same direction as the plunger applies its compressive force to the cartridge to deform the die around the said cavity and increase the load supporting capacity of the die, in which the die is shaped so that its end face opposing the opposing member and constituted by the rings of the die slopes towards the periphery of the die progressively to increase the distance parallel to the axis of the die of the said end face from the opposing face of the said opposing member.

8. Apparatus for generating high all-round pressure in the interior of a metallic cartridge containing a substance that is to be compressed, comprising a die comprised of a apply compressive force to the cartridge to compress the cartridge wholly within the cavity and to apply compressive forces to the central component and rings of the die in the same direction as the plunger applies its compressive force to the cartridge to deform the die around the said cavity and increase the load supporting capacity of the die, in which the die is shaped so that its end face opposing the opposing member and constituted by the rings of the die is stepped radially outwards to the periphery of the die so as in steps to increase the distance parallel to the axis of the die of the said end face from the opposing face of the said opposing member.

9. Apparatus for generating high all-round pressure in the interior of a metallic cartridge containing a substance that is to be compressed, comprising a die comprised of a central component providing a cavity for the said cartridge and surrounding reinforcing rings, said die being adapted to receive the cartridge with an end portion projecting from an end face of the said central component, means including at least one opposed means comprised of a central plunger and surrounding reinforcing rings for causing the plunger, without entering the said cavity, to apply compressive force to the cartridge to compress the cartridge wholly within the cavity and to apply compressive forces to the central component and rings of the die in the same direction as the plunger applies its compressive force to the cartridge to deform the die around the said cavity and increase the load supporting capacity of the die, in combination with rings of plastically deformable material co-operative with said rings of the said die, said plastically deformable rings being of different height in relation to the axial direction of the die and being engageable by the said opposing member for compression thereby to build-up in the die compressive-stress regions progressively outwards to the peripheral region of the die.

References Cited in the file of this patent UNITED STATES PATENTS 2,941,241 Strong June 21, 1960 2,941,245 Cheney June 21, 1960 2,941,248 Hall June 21, 1960 2,995,776 Giardini et al. Aug. 15, 1961 3,061,877 Custers et al. Nov. 6, 1962 3,084,388 Ballhausen Apr. 9, 1963

Claims (1)

1. 5. APPARATUS FOR GENERATING HIGH ALL-ROUND PRESSURE IN THE INTERIOR OF A METALLIC CARTRIDGE CONTAINING A SUBSTANCE THAT IS TO BE COMPRESSED, COMPRISING A DIE COMPRISED OF A CENTRAL COMPONENT PROVIDING A CAVITY FOR THE SAID CARTRIDGE AND SURROUNDING REINFORCING RINGS, SAID DIE BEING ADAPTED TO RECEIVE THE CARTRIDGE WITH AN END PORTION PROJECTING FROM AN END FACE OF THE SAID CENTRAL COMPONENT, AT LEAST ONE OPPOSED MEANS COMPRISED OF A CENTRAL PLUNGER AND SURROUNDING REINFORCING RINGS FOR CAUSING THE PLUNGER, WITHOUT ENTERING THE SAID CAVITY, TO APPLY COMPRESSIVE FORCE TO THE CARTRIDGE TO COMPRESS THE CARTRIDGE WHOLLY WITHIN THE CAVITY AND MEANS TO APPLY COMPRESSIVE FORCES TO THE CENTRAL COMPONENT AND RINGS OF THE DIE IN THE SAME DIRECTION AS THE PLUNGER APPLIES ITS COMPRESSIVE FORCE TO THE CARTRIDGE TO DEFORM THE DIE AROUND THE SAID CAVITY AND INCREASE THE LOAD SUPPORTING CAPACITY OF THE DIE.

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