US3529324A

US3529324A - High pressure generating method and apparatus

Info

Publication number: US3529324A
Application number: US660409A
Authority: US
Inventors: Naoto Kawai
Original assignee: Individual
Current assignee: Individual
Priority date: 1966-08-13
Filing date: 1967-08-14
Publication date: 1970-09-22
Anticipated expiration: 1987-09-22
Also published as: GB1200934A

Description

Sept. 22, 1970 I NAOTO KAWAI HIGH PRESSURE GENERATING METHOD AND APPARATUS Filed Aug. 14, 1967 3 Sheets-Sheet 1 m n H INVENTOR NAO TO KAWAI ATTORNEY Sept. 22, 1970 NAOTO KAWAI HIGH PRESSURE GENERATING METHOD AND APPARATUS Filed Aug. 14, 1967.

3 Shcets-$heet 2 IN VEN TOR ATTORNEY AAAAAAAA AI EEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE US United States Patent Oflice 3,529,324 Patented Sept. 22, 1970 HIGH PRESSURE GENERATING METHOD AND APPARATUS Naoto Kawai, 3-5-1 Sakurai, Mino, Japan Filed Aug. 14, 1967, Ser. No. 660,409 Claims priority, application Japan, Aug. 13, 1966,

41/515,349; Mar. 14, 1967, 42/16,019, 42/21,385, 42/21,386, 42/21,:587, 42/21,.388

Int. Cl. B29c 3/00 US. Cl. 1816 8 Claims ABSTRACT OF THE DISCLOSURE An apparatus for generating high pressure including a multi-stage multi-piston assemblage consisting of a first, second and nth stage multi-piston assemblages, wherein the first assemblage is formed by cutting a solid body of any shape with planes passing through its center and provided in its center part with a pressurized space by truncating the tip of each piston of said assemblage, the second assemblage is formed by cutting another solid body of any shape with planes passing through its center in such manner as to tightly enclose the first assemblage and nth assemblage is formed in this order, the above first to nth assemblages are layered through spacers interposed in the adjacent gaps of the pistons of the respective assemblages and between the respective assemblages and a method for generating high pressure by using the above mentioned apparatus.

This invention relates to methods and apparatus for generating very high pressures with divided multi-pistons.

In conventional very high pressure generating appatus of various forms, there are so many defects that such high pressure as of 500 kb. or more has not been able to be generated.

Among conventional means and methods of generating very high pressures in synthesizing such crystals as of diamond, there is an invention (e.g. US. Pat. No. 3,238,019) utilizing an instantaneous impact force by the explosive force of an explosive. However, such conventional method has a disadvantage that, due to the defect of the mechanism, the impact force will not concentrate at one point but will disperse in a plane. Further,

' in a piston-cylinder type high pressure generating apparatus or a belt-girdle type high pressure generating apparatus for the synthesis of diamond, a hysteresis loop of a high residual pressure will be made in the high pressure energizing process. That is to say, the pressure applied to a substance to be pressurized has never been uniform in the process of the operation of energizing and deenergizing the pressure. In the conventional high pressure generating apparatus, even after the opposed pistons are removed, there has been a residual pressure. In the conventional apparatus, as there is heating limit or a mechanical shrinkage limit of the cylinder, there has been a limit to the pressure that can be reached. However, said pressure limit is low in the double-stage high compression belt type apparatus of F. P. Bundy.

In such one-stage multi-piston pressurizing apparatus as Halls tetrahedral pressurizing apparatus or any other cubic pressurizing apparatus, there are various defects not only in the structure but also in the practical operation. That is to say, all the multi-piston must be syn chronously pressed at the rear ends with respectivve liquid pressure presses. The more the multi-pistons, the more complicated the mechanism of the apparatus. For example, a high pressure generating apparatus having 20 multi-pistons must be driven by 20 liquid pressure presses. It is possible theoreticallyl but is impossible in practice to set such 20 liquid pressure presses in one frame.

On the other hand, the spherical divided multi-piston pressurizing apparatus invented by Baltzar Von Platen is very excellent in the theory of the generation of very high pressures and in the practical operation. (Refer to Modern Very High Pressure Techniques edited by R. H. Wentorf, Jr., PhD, Research Associate, General Electric Research Laboratory, London, Butterworths 1962.)

An experiment was made when, in the spherical divided multi-stage multi-piston type high pressure generating apparatus invented by Baltzar Von Platen, the first stage multi-pistons were made of tungsten carbide, the second stage multi-pistons were made of steel, a spherical body of a diameter of 240 mm. was made in three stages, 6 multi-pistons were set in each stage and each piston was selected to value the same ratio. In the above mentioned experiment, at the time of passing kb. at which germanium shifted to its metallic phase, the first stage multi pistons made of tungsten carbide had fractured at the tips and the second stage multi-pistons and last stage multi-pistons had cracked appreciably on the sides. Fine cracks had been produced also in the rear end surfaces of the first stage multi-pistons made of tungsten carbide. The fine cracks in said rear end surfaces had reached the tips of the first stage multi-pistons and had become larger toward the tips and complete fractures were shown at the tips of the first stage multi-pistons. The active forces which had caused said fractures are by such tensile stress as in the following. That is to say, one of them is a reaction from the substance to be pressurized in the center part. Itis because said reaction strongly acts on the front end surfaces of the first stage multi-pistons. The other cause is the nonuniform reactive forces acting on the rear end surfaces of the first stage multi-pistons through the front end surfaces of the second stage multi-pistons.

Further, the discernible cracks produced in the second stage multi-pistons and the third stage multi-pistons are caused by the tensile stress and bending stress.

One of the various defects in the spherical divided multi-stage multi-piston type high pressure generating apparatus invented by Baltzar Von Platen is because no supporter supporting multi-pistons with each other is interposed. As a result, as Von Platen himself describes, it is presumed that it was impossible to generate such high pressure as was higher than kb. in this type of apparatus. Another defect of the spherical divided multistage multi-piston type high pressure generating apparatus invented by Baltzar Von Platen has been proved by experiments to be due to the dynamic form and mechanism of each stage specifically in view of the generation of very high pressures.

The present invention has improved the above mentioned various defects of the spherical divided multi-stage multi-piston type high pressure generating apparatus of Baltzar Von Platen and relates to an apparatus and method for generating very high pressures by various pressurizing means by applying Baltzar Von Platens apparatus.

The processes of the improving experiments of Baltzar Von Platens apparatus and the constitution of the present invention reached in the course of such many improving experiments shall be explained in turn in the following.

An experiment was made when, in said Baltzar Von Platens apparatus, independent separate spacers or continuous spacers fitting the multi-pistons and interstage spacers were interposed between the adjacent multi-pistons. As a result, fine micro-fractures had expanded to ward the front end surfaces of the first stage multiistons and the generation of pressure above 200 kb. at which the Cilicon (trademark) was to shift to a metal phase failed. However, as the spacer was interposed between the multi-pistons, the generated pressure could be increased. It was because, as the spherical divided multipiston pressurizing device shrank, the spacer developed, acted as a pressure transmitting medium against the unavoidable tensile stress and bending stress of the multipistons increasing with the increasing pressure, produced a compressive stress resisting and compensating the above mentioned tensile stress and bending stress and increased the support between the multi-pistons and between the stages.

Then, an experiment was made when, in the structure of the apparatus, the rear ends of the first stage multipistons were made conical, the front ends of the second stage multi-pistons were made conical holes so as to fit the conical forms of the rear ends of said first stage multi-pistons and the third stage multi-pistons were removed. As a result, it was successful to generate a considerably very high pressure in the pressurized space in said apparatus. It was disclosed that the first stage multipistons were pressurized and shrunk by the second stage multi-pistons, the resistance of CdS embedded in the pressurized space of the first stage multi-pistons became maximum and therefore a pressure of about 465 kb. was generated in the pressurized space in the center part. However, due to the increased tensile stress generated within, the rear parts of the first stage multi-pistons could not endure the very high pressure above 500 kb. and fractured into fine pieces.

As a result of many improvements and experiments made as mentioned above, the present invention has been reached.

An object of the present invention is to provide a multi-stage multi-piston type high pressure generating apparatus for synthesizing such substances as diamond, cubic BN, metallic III-V compounds, metallic II-VI compounds, spinel Mg SiO ilmenite MgSiO or stitiovite.

Another object of the present invention is to provide a multi-stage multi-piston type high pressure generating apparatus formed of multi-pistons of different numbers of divisions.

A further object of the present invention is to provide a multi-stage multi-piston type high pressure geenrating apparatus wherein multi-pistons in respective layers are connected and are driven toward the pressurization of the center part.

Another object of the present invention is to provide a multi-stage multi-piston high pressure generating apparatus wherein concaves for absorbing broken pieces of spacers or the like are provided in multi-pistons.

A further object of the present invention is to provide a fluid pressurizing type high pressure generating apparatus formed of multi-stage multi-pistons and a method of generating very high pressures by means of said fluid pressurizing type high pressure generating apparatus.

Another object of the present invention is to provide an explosive pressurizing type high pressure generating apparatus formed of multi-stage multi-pistons and a method of generating very high pressures by means of said explosive pressurizing type high pressure generating apparatus.

Another object of the present invention is to provide a liquid pressure press type high pressure generating apparatus formed of multi-stage multi-pistons and a method of generating very high pressures by rneans of said liquid pressure press type high pressure generating apparatus.

A further object of the present invention is to provide a method of generating very high pressures by setting and combining a plurality of fluid pressurizing type high pressure generating apparatus in an autoclave.

In the present invention, a solid geometrical body of any such forms as spherical, cylindrical, elliptical, hexahedral, octahedral, dodecahedral and icosahedral forms is split into a plurality of congruant shaped pistons passing through its center so that the first stage-multipiston assemblage may be formed, each piston in said first stage multi-piston assemblage is truncated at the tip so that a pressurized space may be retained in the center part of the first stage multi-piston assemblage, then another solid geometrical body of any of such forms as spherical to icosahedral forms enclosing the above mentioned first stage multi-piston assemblage is multi-divided with flat planes or curved planes or a combination of them passing through its center so that the second stage multi-piston assemblage may be formed, further a hollow space of any of such forms as spherical to icosahedral forms enclosing the above mentioned second stage multipiston assemblage is multi-divided with flat planes passing through its center so that the third stage multi-piston assemblage may be formed, and nth stage multi-piston assemblage is formed in such order, a specimen enclosed with a gasket and connected with an electricity passing device is arranged in the pressurized space of the first stage multi-piston assemblage and the first to the nth stage multi-piston assemblages are thus piled up by interposing spacers in the adjacent gaps of the pistons of the respective stage multi-piston assemblages so that a multi-stage multi-piston assemblage may be formed.

In the present invention, absorbing concaves into which broken pieces of the spacers and excluded gaskets are to be fitted are provided on the side surfaces of the divided multi-pistons so that the shrinkage to the pressurized space in the center part of the multi-pistons may be improved and the external acting force of the multi-pistons may be etficiently transmitted to the pressurizing substance.

Further, in the present invention, engaging and fitting convexes and concaves may be provided in the side parts of the adjacent multi-pistons so that the multiplied driven shrinkage of the multi-pistons to the pressurized substance may be made.

The structure of the above mentioned multi-stage multi-pistons in the present invention shall be explained in the following with several examples:

(1) A total of 92 cones consisting of 20 large cones, 12 medium cones and 60 small cones respectively the same in the height from the apex to the bottom surface but different in the diameter are truncated at the respective pointed apexes so that conical multi-pistons may be formed and, in case said conical multi-pistons are assembled, a spherical pressurized space may be retained in the center part. Further, the outside forms of said conical multi-pistons are made spherical. A pressurized material enclosed with a gasket and connected with an electricity passing device is arranged in the above mentioned pressurized space. Said conical multi-pistons are respectively fitted to a honey comb-shaped integral continuous spacer so that the first stage multi-pistons may be formed. Further, a spherical body is divided into 8 portions so that the second stage multi-pistons may be formed. Individual or integral continuous spacers are interposed also between said second stage multi-pistons so that the second stage multi-pistons may be formed. As required, interstage spacers are interposed between the first stage multi-pistons and the second stage multi pistons. An electric conductive device is provided be tween specific pistons of the first stage multi-pistons and the second stage multi-pistons. Said second stage multipistons have an internal space substantially similar to the outside form of said first stage multi-pistons. The first stage multi-pistons are internally provided in said internal space of said second stage multi-pistons so that the two-stage layer multi-pistons may be formed.

(2) An octahedron is divided into 6 portions with flat planes passing through its center. The first stage multipiston assemblage is formed of 6-divided multi-pistons having four bottoms with the respective apexes of the octahedron as centers. Further, said first stage multipiston assemblage is truncated at the internal center (pointed ends). The front of each piston is made a regular tetrahedron and a regular hexahedral pressurized space is formed in the center part of the assemblage of said 6-divided multi-pistons. Further, the second stage multi-piston assemblage is formed by 8-dividing a spherical body. The above mentioned second stage multi-piston assemblage has an internal space similar to the outer form of the above mentioned first stage multi-piston assemblage. The first stage multi-pistons are internally provided in said internal space of the second stage multi piston assemblage. The gasket, spacer and electric conductive device are arranged in the same manner as in the preceding paragraph 1 so that two-stage layer multi-pistons may be formed.

(3) A cube is divided into 8 small cubes so that the first stage multi-piston assemblage may be formed. Said first stage multi-piston assemblage is truncated in the center of the assemblage. The front of each piston is made a regular triangular surface and a regular octahedral pressurized space is formed in the center part of said first multi-piston assemblage. Further, a spherical body or cubic body is uniformly divided into six portions so that the second stage multi-piston assemblage may be formed. The above mentioned second stage multi-piston assemblage has an internal space similar to the outer form of the above mentioned first stage multi-piston assemblage. The first stage multi-pistons are internally provided in said internal space of the second stage multi-piston assemblage. The gasket, spacer and electric conductive device are arranged in the same manner as in the preceding paragraph 1 so that two-stage layer multi-pistons may be formed.

(4) A dodecahedron is divided into 12 portions with flat planes toward the center from the respective edges so that the first stage multi-piston assemblage may be formed. Said first stage multi-piston assemblage is truncated in the center of the assemblage. The front of each piston is made a regular pentagon and a regular dodecahedral pressurized space is formed in the center part of said first stage multi-piston assemblage. Further, an icosahedron is divided into portions toward the center from its edges so that the second stage multi-piston assemblage may be formed. Or the icosahedron is divided into 12 portions with flat planes passing through its center. Each apex of the icosahedron is made a center and the second stage multi-piston assemblage is formed of 12-divided multi-pistons having 5 outside surfaces. The above mentioned second stage multi-piston assemblage has an internal space similar to the outer form of the above mentioned multi-piston assemblage. The first stage multi-piston assemblage is internally provided in said internal space of the second stage multi-piston assemblage. The gasket, spacer and electricity passing device are arranged in the same manner as in the preceding paragraph (1) so that two-stage layer multi-pistons may be formed.

In the above mentioned examples, only two-stage layer multipistons are shown. But, in the objects and constitutions of the present invention, such multi-stage layer multi-pistons as S-stage layer multi-pistons and 4-stage layer multi-pistons can be formed by piling up multidivided multi-pistons of any of the. above mentioned forms in turn on the outer periphery of the second stage multi-pistons.

Various forms of two-stage layer multi-pistons formed by multi dividing solids of any of geometrical forms and combining the first stage multi-pistons and second stage multi-pistons shall be exemplified in the following table.

FIRST STAGE MUL'll-PISTONS Second stage multi-pistons Solid forms: Number of divisions Sphere 4, 6, 8 Hexahedron 8 Octahedron 6

Dodecahedron

6, 8, 12, 20

Icosahedron

12, 20

The number of two-stage layer multi-pistons formed of a combination of the first stage multi-pistons and second stage multi-pistons consisting of the number of divisions of some solids exemplified in the above table is 121. Further, if the third stage multi-pistons of the same form and number of divisions as of the second stage multipistons shown in the above table are piled up on the outer periphery of said two-stage layer multi-pistons, there will be obtained 14,641 three-stage layer multi-pistons having different structures.

Now, a few examples shall be enumerated and explained.

(1) Layer structure of octahedral and cubic multi-piston assemblages: An octahedron is divided with many planes passing through its geometrical center to form 6 multi-pistons of the first stage assemblage. The octahedron has 8 inclining outer surfaces and 6 apexes. Each piston is made in such a way that the piston may have its front center which is situated at the center of the octahedron and also may have its rear center which is the above mentioned apex. From the front center are developing four inclining dividing planes and also from the rear center are developing four pyramid surfaces of the octahedron, the former planes and the latter surfaces being jointed in the middle of each octahedron surfaces forming the four lateral edges of each piston. Each piston is then truncated at the center with a plane so that the assemblage of the multi-pistons may form a cubic cenral hollow space in which is inserted a specimen to be compressed.

The second stage multi-piston assemblage is made of 8 cubes which are also truncated at the centers so that the assemblage may form a central octahedral hollow space in which is inserted the first stage assemblage previously made. The second stage assemblage with 8 cubic pistons is cubic in the form.

The third stage assemblage is made of 6 wedged-shaped pistons, each having one square front face, four inclining lateral surfaces and one square rear face or a surface which is a part of the sphere (actually /6 of the spherical outer surface.) The third stage assemblage can contain in its central hollow space the second stage assemblage.

Further layers on the third stage assemblage are possible to the nth multi-stage piston assemblage. Successive layers of 6, 8, 6, 8 multi-pistons one by one are, therefore, possible.

(2) Layer structure of icosahedral multi-piston assemblages: The first stage assemblage is an icosahedron divided with many planes passing through its geometrical center to form 12 multi-pistons.

The icosahedron has 20 triangular surfaces and 12 apexes, each being formed by the junction of the inclined five neighbouring triangular surfaces.

Each piston is so made that, by the division, it may have its front center which is situated the center of the icosahedron and may have also its rear center which is the above-mentioned apex. From the front center are developing inclining dividing planes whilst from the rear center 5 neighbouring triangular outer faces, the former planes and the latter surfaces join together at the center of the icosahedral outer faces to form 5 lateral edges of the piston. Each piston is truncated at the center so that when 12 pistons are assembled, they may form a central hollow space which is dodecahedral in the form.

Into this hollow space is put a dodecahedral specimen to be compressed.

The second stage multi-piston assemblage will be made when there is made another icosahedron having an icosahedral internal hollow space in which is to be fitted the first stage multi-piston assemblage and then it is divided with many planes passing through its center to form multi-pistons, each having 3 inclining lateral dividing planes and one rear face which coincides with one of the triangular surfaces of the icosahedron.

The third stage multi-piston may be a larger icosahedral assemblage consisting of 12 multi-pistons whose geometry is similar to that of the first one and can contain inside it the second stage assemblage.

Successive and alternate layers of 12, 20, 12 multipistons can be therefore constructed one by one.

(3) Dodecahedral multi-stage multi-piston assemblage: This first stage multi-piston assemblage should be a dodecahedron divided also with many planes passing through its geometrical center to form 20 multi-pistons.

The dodecahedron has 12 pentagonal outer surfaces and 20 apexes, each being formed by the junction of the three neighbouring outer surfaces.

Each piston is so made that by the division, it may have each front center which is situated at the center of the dodecahedron and may have each rear center which coincides with the above-mentioned apex. From the front center are developing 3 inclining dividing planes and from the rear center dodecahedron surfaces, the former planes and the latter surfaces meeting at the center of the pentagonal outer surfaces forming three lateral edges of each piston.

Each piston is truncated at the center so that 20 multipistons, when put together, may form a central hollow space which is icosahedral in the form. Into this space is put an icosahedral specimen to be compressed.

The second stage multi-piston assemblage will be made when there is made another dodecahedron having a dodecahedral inner hollow space in which is to be fitted the first stage assemblage and then it is divided with many planes passing through its center to form 12 multi-pistons, each having 5 inclined lateral dividing planes and one rear pentagonal surface of the dodecahedron.

The third stage assemblage is a larger dodecahedron divided into 20 multi-pistons whose form is similar to that of the first stage piston.

Successive and alternate layers of 20, 12, 20, multi-pistons can be therefore constructed one by one.

It is characteristic of all types of the multi-stage multipiston assemblages that the gaps to be formed in the inner layer assemblage and to appear between the neighbouring pistons are partly and nearly completely covered with the front surfaces of the pistons of the outer layer assemblage.

As described above, the multi-stage multi-pistons according to the present invention are formed of layers of any stage multi-pistons formed by multi-dividing solids of any forms.

In the present invention, a fluid pressurizing type high pressure generating apparatus is formed by completely coating and enclosing the above mentioned multi-stage multi-pistons with a shell cover having an electric conductive device and a plurality of the above mentioned fluid pressurizing type high pressure generating apparatus are set in an autoclave so that, when a fluid pressure is applied, a very high pressure may be integrally generated.

Further, in the present invention, a sealing member is fitted in the adjacent gaps of nth stage layer multi-piston assemblage outside the above mentioned multi-stage multi-pistons and is completely sealed and tightened in the upper end part with a metal fixture to form a fluid pressurizing type high pressure generating apparatus and a plurality of such fluid pressurizing type high pressure generating apparatus are set in an autoclave so that, when :a fiuid pressure is applied to them, a very high pressure :may be integrally generated.

Further, in the present invention, a mechanical press type high pressure generating apparatus is formed by making an nth stage multi-piston assemblage outside the "above mentioned multi-stage multi-pistons in the combined form of an inverted cone and upright cone and is ;set between the head and ram of a mechanical press so :that a very high pressure may be generated.

In order to make the objects and formation of the present invention more definite, several embodiments shall be explained in the following with reference to the drawings in which:

FIG. 1 is a sectional view of a fluid pressurizing type high pressure generating apparatus formed of two-stage ;layer multi-pistons;

FIG. 2 is a sectional view on line IIII in FIG. 1;

FIG. 3 is a perspective View of a single piston of the :first stage multi-pistons shown in FIGS. 1 and 2;

FIG. 4 is a sectional view of a fluid pressurizing type v high pressure generating apparatus formed of one-stage .multi-pistons made by providing each piston of spherical 8-divided multi-pistons with a concave for absorbing .broken pieces of gaskets and spacers;

FIG. 5 is a perspective view of a single piston of the spherical S-divided multi-pistons shown in FIG. 4;

FIG. 6 is a perspective view of an integral continuous spacer to which 8-divided multi-pistons shown in FIG. 25 are to be fitted;

FIG. 7 is a sectional view of a fluid pressurizing type high pressure generating apparatus formed of one-stage spherical 8-divided multi-pistons each of which is provided with an engaging and fitting convex and concave;

FIG. 8 is a perspective view of a single piston of the spherical 8-divided multi-pistons shown in FIG. 7;

FIG. 9 is a perspective view of a fluid pressurizing type high pressure generating apparatus formed by fitting a sealing member in the adjacent gaps of the first stage multi-pistons consisting of cylindrical 8-divided multipistons;

FIG. 10 is a sectional view on line X-X in FIG. 9

FIG. 11 is a perspective view of the sealing member in FIGS. 9 and 10;

FIG. 12 is an explanatory view of a method of integrally generating very high pressures by internally providing a plurality of the above mentioned fluid pressurizing type high pressure generating apparatus formed of one-stage multi-pistons, two stage layer multi-pistons or multi-stage layer multi-pistons in an autoclave and applying a fluid pressure to them;

FIG. 13 is an explanatory view of a method of generating very high pressures by means of an explosive pressurizing type high pressure generating apparatus in which an explosive is arranged on the outer periphery of onestage multi-pistons consisting of spherical S-divided multipistons;

- FIG. 14 is an explanatory view of a method of generating very high pressures by means of a liquid pressure press type high pressure generating apparatus formed of three-stage layer multi-pistons.

FIGS. 1 to 3 show a fluid pressurizing type high pressure generating apparatus formed of two-stage layer multipistons among fluid pressurizing type high pressure generating apparatus formed of multi-stage layer multi-pistons according to the present invention. The first stage multipiston assemblage 11 consists of 32 conical pistons 12 each having the tip part 13 of a large curvature directed toward the center and the rear end part 14 of a small curvature assembled outside as shown in FIG. 3. Therefore, the first stage multi-piston assemblage has a spherical pressurized space 15 in its center part and is substantially spherical even outside. In this embodiment, the first stage multi-piston assemblage 11 is formed of only conical pistons 12 having the same diameter. But the first stage multi-piston assemblage may be formed of large, medium and small conical multi-pistons of the same height but different in the diameter. For example, though not illus trated, a total of 92 cones of large cones, 12 medium cones and 60 small cones of the same height from the apex to the bottom surface but diflerent in the diameter are truncated at the respective apexes and are assembled to form the first stage multi-piston assemblage.

A sample to be pressurized and enclosed with such gasket as of pyrophyllite and connected with an electric heating device is embedded, though not illustrated, in the pressurized space 15 in the center part of the first stage multi-piston assemblage 11. Further, the first stage multipistons 11 are fitted to a honeycomb-shaped spacer 16 having a space in the center and are assembled.

The second stage multi-piston assemblage 17 is formed of 8 multi-pistons 18 made by dividing a regular column into 8 portions with normally intersecting flat planes passing through its center, forming a space substantially similar to the outside form of the first stage multi-piston assemblage 11 within the divided column and further truncating the inside of each of the normally intersecting outer end surfaces of the two plane dividing lines with the other normally intersecting plane.

As required, an interstate spacer is applied in contact with the outside of the above mentioned first stage multipiston assemblage 11 and the second stage multi-piston assemblage 17 is piled up on the outer periphery of said spacer by interposing several individual spacers or an integral continuous spacer between the pistons 18 so that a two-stage layer multi-piston assemblage may be formed. An electric conductive device is provided through the interstage spacer between specific pistons of the first stage multi-piston assemblage 11 and second stage multi-piston assemblage 17. Further, a pad 20 made of an insulating material or mixed with an insulator is applied in contact with the above mentioned truncated surface in the outer end part of the second multi-piston assemblage 17.

The above mentioned two-stage layer multi-piston assemblage and pads are coated with paired covers 21 which are made of a flexible rubber or synthetic resin and through which are passed electric conductive wires (not illustrated) and are perfectly sealed with metal fixtures (not illustrated) so that a fluid pressurizing type high pressure generating apparatus may be formed. The method of generating very high pressures by means of said fluid pressurizing type high pressure generating apparatus shall be explained with reference to FIG. 12.

In FIGS. 4 to 6, in the multi-stage layer multi-piston assemblage shown in FIGS. 1 to 3 (the first stage multipiston assemblage is omitted in FIGS. 4 to 6 such integral continuous spacer 22 as is shown in FIG. 6 is provided on the adjacent surfaces between the pistons 18 of the second stage multi-piston assemblage 17 and one or more concaves 23 are made on the surface of each piston 18 in contact with the spacer 22. The reason for providing the above mentioned concaves 23 is as follows. In the case of generating a very high pressure by the later described method in the present apparatus, the multi-piston assemblage in each stage will be subjected to an external pressure, will be driven and shrunk toward the pressurized space situated in the center part and will compress the pressurized substance enclosed with a gasket in the pressurized space and, under a fixed pressure, the gasket will act as a packing to prevent the pressurized substance from leaking out and to efficiently compress the pressurized substance but, when the external pressure rises to be higher than that, the leakage preventing gasket will rather become a resistor to the pressure and, under a considerable pressure, the spacer will be destroyed and the destroyed spacer will also become a resistor to the transmission of the pressure to the pressurized space.

The above mentioned concaves 23 will act to absorb such leaking gasket and destroyed spacer and will increase the efiiciency in the pressure transmission.

The spacer is made of such flexible and insulative material as paper, wood, synthetic resin, rubber, indium, lead or bismuth. The above mentioned cover 21 is made of such flexible material as rubber or synthetic resin. In the case of measuring and sintering the pressurized substance simultaneously with the pressurization, an electric conductive wire 24 is provided in said cover 21.

The apparatus shown in FIGS. 7 and 8 is similar to the apparatus shown in FIG. 4. It is the same as in the above mentioned apparatus that a solid sphere is divided into 8 portions with planes passing through its center, each piston 18 of the 8-divided 'multi-piston assemblage 17 is truncated at the tip with an inclined plane and the first multipiston assemblage (not illustrated) is arranged in the center part of the 8-divided multi-piston assemblage. But, a convex 26 is made on one adjacent side 25 of each piston 18 of the multi-piston assemblage 17, a concave 28 is made on the other side 27 and said convex 26 and concave 28 are engaged with each other by interposing a spacer 29. This, in case the multi-piston assemblage 17 is driven and shrunk toward the pressurized space in the center part, the nonuniforrnity of the pressure to which each piston 18 is subjected will be able to be corrected, the displacement of each piston due tothe difference of the frictional resistance on the side between the respective pistons will be able to be prevented and the geometrically normal position will be able to be always kept.

In the apparatus shown in FIGS. 9 to 11, a spacer 30 is interposed in the adjacent part of each piston 18 of the multi-piston assemblage 17 formed in the same manner as is mentioned above and such sealing member 31 as is shown in FIG. 11 is arranged on the outer periphery of the assemblage and is enclosed and tightened on the outside with a metal fixture 32. In such case, such cover 21 as is shown in FIGS. 1 to 8 is not required.

FIGS. 12 to 14 relate to an apparatus for working a a method of applying a very high pressure to the apparatus formed as mentioned. In FIG. 12, a plurality of units 33 each made by fastening the already particularly described multi-stage multi-piston assemblage with the cover or metal fixture are arranged in a container 34 and a high pressure fluid is fed under a pressure through a pipe 35 so that a very high pressure may be simultaneously generated in the respective stage multi-piston assemblages in the respective units 33. In such case, a powdery pressurized substance contained in the pressurized substance contained in the pressurized space in the center part of the first stage multi-piston assemblage and enclosed with such gasket as, for example, pyrophyllite will be highly compressed from all the three-dimensional peripheral surfaces.

FIG. 13 is of a method of applying a high pressure to each unit as different from the method of feeding a high pressure fluid by containing the respective units integrally in a high pressure container. The multi-piston assemblage 17 is covered on the outer periphery with a flexible substance 36 is provided with a space 37 and is covered on the outside with such substance comparatively thicker than the above mentioned substance 36 as rubber.

Gunpowders

39, 40, 41 and 42 are arranged to meet the outsides of the respective pistons 18 of the above mentioned multi-piston assemblage 17 in the above mentioned space 37 and

lead wires

43, 44, 45 and 46 are respectively fitted to the gunpowders so that, simultaneously with the explosion of the gunpowders, a very high pressure will be generated and will be able to be given to the pressurized substance through the multi-piston assemblage. In order to simultaneously ignite the above mentioned gunpowders, it is preferable to use such bursting charge high in the combustion velocity as trinitrotoluene on the outer peripheral surfaces of the gunpowders so that such very high pressure as is more than 10,000,000 atmospheres may be generated. The lead wire 47 is connected to a heating means which can heat the pressurized space and is adapted to heat the substance in said space to a high temperature. The other lead wire 48 is connected to a measuring means adapted to show the temperature condition of the pressurized substance and the variation of the resistance value.

In the apparatus shown in FIG. 14, the first stage multipiston assemblage is also a sphere which is divided into portions, the form being arbitrary so long as the division has a point symmetry at the sphere center. The second stage multi-piston assemblage is paired tetrahedrons jointed on the base and horizontal planes common to each other. These paired tetrahedrons are divided by three vertical planes and one horizontal plane all passing through the center to form 6 tapered wedge-shaped pieces. The third layer has such assemblage that it has an outer surface made of paired cones jointed also on their base and horizontal planes common to each other and has an inner surface on which is fitted the above mentioned second stage assemblage. This third multi-piston assemblage is divided also into six portions to be placed to cover the gaps formed by the adjacent portions of the second multipiston assemblage. Similarly covering of the second multipiston assemblage over the gaps in the outer surface of the first stage will be also satisfactory when the two layers are put together.

In order to generate a high pressure in each unit, when the unit is placed between an upper ram 49 and a lower ram 50 and both upper and lower rams are pressed with a mechanical press, a high pressure will be able to be given to the substance in the pressurized space in the center part in the multi-stage multi-piston assemblage.

In short, according to the present invention, the multistage multi-piston assemblage has the following special characteristics that gaps made between the multi-pistons in one particular stage assemblage are completely or partly covered with the front surface of one piston or those of several pistons of the next stage assemblage. Consequently, the tendency of the specimen and stretched spacers to flow outwards semi infinitely through the gaps can be prevented on the layer-layer boundary by the front surface or surfaces of the assemblage pistons in the outer layer assemblage. Some of these gaps are inevitably covered by differentiating the number of the multi-pistons in the respective stages, but the present invention aims to cover the gaps, as many as possible, by shifting the phases of the gaps in the respective stages.

The multistage multi-piston assemblage has self-adjusting devices to keep a geometrical relation of all the pistons quite constant throughout the entire course of both of the elevating and releasing procedures.

Furthermore, the present apparatus has another selfadjusting mechanism whereby compressive stresses in the multi-pistons can be balanced in the assemblage, increasing the stress with the increase of the internal pressure or decreasing the stress with the decrease of the internal pressure being automatically provided.

A pressure gradient increasing towards the center along the radius of the assemblage will occur during the procedure. The condition resembles conspicuously that prevailing in the interior of the earth.

Finally, in the case of one-stage multi-piston apparatus to be driven by a back-up hydraulic press, besides the above-mentioned difficulties, there will arise another mechanical complexity which will increase, when the number of the multi-pistons is larger. In fact, the realization of 2'0 multi-piston apparatus driven by 20 hydraulic presses all mounted on one framework is theoretically possible but is not practically feasible at all.

The present method by means of multistage multi-pistons has made it possible to realize ultramulti-piston system, for example, a 32i-cone multi-piston assemblage or 60- tapered prism shaped multi-piston assemblage with a very high pressure amplification rate.

It has been also found with a series of experiments that a higher pressure will be obtainable when the body is divided into more multi-pistons.

A multistage multi-piston assemblage to be pressurized by explosive forces to occur at a time when gunpowders placed around the assemblage are synchronously fired can produce a pressure 10 to times as high as the maximum pressure reached with a method of static production by using the same multistage multi-piston assemblage in a compressed liquid.

When a thick continuous spacer is sandwiched between the multi-pistons before the firing and then its thickness is reduced to A of its original value by the explosion, the volume of the specimen in the central space will be reduced greatly by a factor of 10' Since this enormous volume contraction is undertaken instantaneously Within a period of less than 0.1 sec., the compression of the central body placed in it can be con sidered to be an adiabatic compression. Therefore, there can be expected a large temperature elevation as well as a pressure increment within a reduced volume of the shrunk assemblage after the firing.

When the temperature inside the space is preliminary elevated with a heater up to 1000 C., the temperature will have to increase up to 10 c. and pressure up approximately to 1 kb. due to the above mentioned adiabatic compression caused by the instantaneous shrinkage.

In order to make synchronous firing of gunpowders placed on respective multi-pistons, a tape TNT power is employed as a wound and laid on the outer surface of the outermost multi-pistons. The firing velocity is so high that it is possible to make a synchronous explosion with an error smaller than 0.1 msec. A special shrinkage by the help of a plate placed on the contact surface common to several multi-pistons will take place also in this compression. A so-called shock experiment undertaken to produce an intense compression is entirely different from the experiment by using multi-pistons and gunpowders. In the former, the energy will be restricted on a plane having a certain area. In the latter, however, the energy will be concentrated in a very small volume tending finally to be a single point. The total energy concentration will be, therefore, proportional to 'y in an experiment where 'y is the radius of the compressed volume. Total energy will diverge in a certain area in the case of a shock plane wave experiment.

It is possible to cause the melting of diamond in an atmosphere in which diamond will solidify into solid diamond to get a large aggregate of polycrystalline crys tals. Similar melting experiments are possible to obtain the solid aggrigates of II-VI compound polycrystalline crystals such as of ZnO or ZnTe or their grains and those of III-V compound polycrystalline crystals such as of GaAr or B, N. Other materials having high melting points can also be melted and their polycrystalline crystals or grains can be formed. It may be possible to produce by this method exotic materials so far unknown on the earth.

When the shrinkage techniques are improved one step further in future and the thickness of the spacer can be further stretched by a factor of the temperature and pressure will be able to be magnified by a factor of the order of 10. When a previous heating temperature inside the space to be reduced is elevated up to 100 C. before the firing and the shrinkage is followed, a temperature of 10 degree C. and simultaneous pressure of 10 bars will be able to be obtained: The representation of the sun in the laboratory being no longer a mere dream.

Embodiments of the two-stage layer high pressure generating apparatus according to the present invention and illustrated in FIGS. 1 to 3 shall be shown. The respective component elements are as follows:

(1) The first stage spherical assemblage is of a diameter of 125 mm.

(2) The material of the multi-pistons of the above assembage is sintered tungsten carbide having 6% Co as a binder.

(3) The diameter of the central hollow space in which is placed the specimen to be compressed is 6 mm.

(4) The pressure indicator embedded in the spherical specimen is of CdS.

(5) The above spherical specimen is made of pyrophyllite.

(6)The continuous spacer of the first stage multi-pistons with a honey-comb structure is made of Nylon (trademark).

(7) The mean thickness of the continuous spacer holding the multi-pistons is 0.4 mm.

(8) The layer-layer spacer between the first stage assemblage and the second stage assemblage is made of Teflon) trademark).

(9) The thickness of the layer-layer spacer is 0.4 mm.

(10) The second stage cylindrical multi-piston assemblage having 8 divided multi-pistons is of a diameter of 250 mm.

(11) The material used to construct the second stage assemblage is a hardened steel of S.N.C.M. 2.

(12) The separated spacer sandwiched between the multipistons of the second stage assemblage is of ordinary soft paper.

(13) The thickness of the spacer is 1.4 mm.

(14) The cover to enclose the entire assemblage is made of rubber.

( 15 2 plates put on the top and bottom surfaces are made by cutting the upper part of the assemblage with planes and 4 plates put on the lateral form surface are made also by cutting it with planes. These plates are made of Bakelite (trademark).

(16) The mean thickness of the plate is 15 mm.

By using those elements mentioned above and compressing the entire body with oil compressed under 500 bars, it has been confirmed that the pressure indicator of CdS has shown its maximum resistance. By Drickamer and Samaras experiments it has been confirmed that the true pressure under which the resistance of the material approaches the maximum is 465 kb. This shows that the present apparatus can produce a pressure of an order of 500 kb. or even more. 1

An example of an experiment made by using a two stage multi-piston assemblage having 8 inner layer cubic multi-pistons truncated at the centers with planes and 6 outer layer multi-pistons forming a spherical outer surface shall be described in the following:

The diameter of the entire assemblage is 240 mm.

The rubber shell cover is 10 mm. thick.

The specimen medium to be placed and compressed within the inner layer assemblage is made of pyrophyllite.

The specimen, being octahedron in the form, has a dis tance of exactly 6 mm. between the two most separated apexes before the compression.

The inner layer cubic multi-pistons have each side 30 mm. long.

The first stage assemblage has a cubic outer form and an octahedral central hollow space.

The outer layer multi-pistons have a spherical outer form and a cubic central hollow space in which is placed the first stage assemblage. The enclosed assemblage is compressed in oil under an elevated pressure.

In the central octahedron is embedded Ge, Si, GaAr or CdS whose electric resistance under an increasing pressure is continuously measured. An electric lead Wire is taken out of the entire assemblage and rubber shell and also through the liquid reservoir. The enclosed entire assemblage is put into the oil and the oil pressure is elevated by means of a pump. When the oil pressure is ele vated up to atm., Ge will be first transformed to its metallic form and the original electric resistance of 2009 will suddenly drop down to 10. When the oil pressure reaches atm., Si will be transformed to its metallic form and the original electric resistance of 2009 will again drop down to 10. When the oil pressure reaches 240 atm., GaAr will be transformed to its metallic form and its electric resistance of 76 K0 will drop down to 38.3 KB.

Finally CdS will show its maximum resistance when the oil pressure approaches 430 bars.

According to experiments made by Drickamer et al., Ge, Si, GaAr will be transformed to their respective metallic forms under pressures of 120, and 240 atm. respectively. It has been also found by Drickamer et al. experimentally that CdS will show its maximum resistance under a pressure of 465 kb. It is quite surely concluded therefore that the two stage multi-piston assemblage of the present invention has a pressure magnification factor slightly higher than 1000.

What is claimed is:

1. A high pressure generating apparatus comprising a multi-stage multi-piston assemblage having at least two concentric stages, each of said at least two concentric stages comprising a plurality of pistons, said plurality of pistons being congruent sections of a solid regular geometrical body and having corresponding adjacent inner ends, adjacent ones of said plurality of pistons within any one of said at least two concentric stages having surfaces which belong to common planes, said planes passing through the geometrical center of said body, a first stage comprising first stage pistons having a first central space of regular geometrical shape, the tips of the inner ends of said first stage pistons being truncated to form said first central space, a subject to be pressurized deposited in said first central space, an nth stage comprising nth stage pistons having nth central space of regular geometrical shape, said nth stage enclosing an (n1)th stage having (n1)th stage pistons within said nth central space, the number of (n-1)th stage pistons being different from the number of nth stage pistons, said nth stage being so disposed that the outer ends of at least two of said (n--1)th stage pistons are in contact with the inner end of one of said nth stage pistons, gaps present between the (n1)th stage pistons being at least partly covered by the inner end of at least one nth stage piston, a last stage comprising stage pistons having a last central space enclosing a nextto-last stage, inter-piston spacers interposed in said gaps between adjacent said plurality of pistons, inter-stage spacers interposed between each of said at least two con centric stages, containing means enclosing outer ends of said last stage pistons, and means for applying equal pressure to each of said outer ends of said last stage pistons.

2. A high pressure generating apparatus as claimed in claim 1 wherein an electric conductive device passes through said inter-stage and inter-piston spacers and passes between predetermined ones of said plurality of pistons, at least one of said first stage pistons serving as an electric conductor to supply electric current to said first central space.

3. A high pressure generating apparatus as claimed in claim 1, at least one of said surfaces of said plurality of pistons having at least one concave portion.

4. A high pressure generating apparatus as claimed in claim 1, wherein mating convex and concave parts are formed on at least two adjacent said surfaces of said plurality of pistons.

5. A high pressure generating apparatus as claimed in claim 1, said inter-stage and inter-piston spacers forming a single integral continuous spacer.

6. A high pressure generating apparatus as claimed in claim 1, said means for applying equal pressure comprising explosives mounted in each of said outer ends of said 15 16 last stage pistons, and means for simultaneously firing Said explosives References Cited 7. A high pressure generating apparatus as claimed in UNITED STATES PATENTS claim 1, said means for applying equal pressure compris- 3,118,177 1/1964 Von platen mg a pressurized autoclave, said autoclave contaimng a- 5 3,149,374 9/1964 Wagner.

fluid, said multi-piston assemblage being deposited within 3,179,979 4/1965 Bundy et a1. said autoclave. 3,201,828 8/1965 Fryklund.

8. A h1gh pressure generating apparatus as claimed in claim 1, said means for applying equal pressure compris- WILB-UR L. MCBAY, Primary Examiner ing a mechanical press, and means for distributing the 10 axial pressure of said press equally to each of said outer ends of said last stage pistons.