US3374501A - High pressure press - Google Patents

Description

March 26, 1968 0. H. NEWHALL HIGH PRESSURE PRESS Filed May United States Patent 3,374,501 HIGH PRESSURE PRESS Donald H. Newhall, Walpole, Mass., assignor to Harwood Engineering Company, Walpole, Mass, a corporation of Massachusetts Filed May 21, 1965, Ser. No. 457,700 7 Claims. (Cl. 18-16.5)

ABSTRACT OF THE DISCLOSURE The disclosure of the invention comprises a high pressure press assembly having, in combination, a pair of opposed anvil elements,

each comprising a cylindrical base of large cross sectional area for supporting a maximum axially directed load imposed on said high pressure press assembly, and adjacent said base converging surfaces terminating in a specimen engaging work face of relatively smaller area concentrating said axially directed load therein, a support cylinder having an internal cylindrical wall extending between and overlying each of said cylindrical bases,

fluid pressure containing seals between said internal cylindrical Wall and each of said cylindrical bases, providing with said support cylinder and anvil elements a pressure fluid containing enclosure,

means for subjecting said anvil elements to an axially directed compression pressure, and

means directing fluid under pressure into said fluid pressure containing enclosure providing an evironmental pressure against any included specimen and exposed surface of said anvil elements between said seals including said converging surfaces and specimen engaging work faces, including means for controlling the fluid pressure within said enclosure to establish a desired relationship of said environmental fluid pressure to axial thrust which is independent of volumetric variation of said enclosure.

A layer of plastic material may overlie said specimen between the anvil elements for protection from said pressure fluid. The specimen may be engaged by a sup porting ring of high tensile strength with a sealing ring between the ring and each adjacent anvil element. The construction may also include an anvil tip of transparent material and a supporting anvil base formed with a visual inspection channel therein.

The present invention relates to improvements in high pressure apparatus and more particularly to a high pressure press of the general type opposed anvils acting along a single axis.

High pressure apparatus of the general type having opposed anvils with tip portions of reduced area for engaging a specimen therebetween, wherein said tip portions are externally formed to support maximum pressures within the confines of the opposed anvil surfaces, and in which the specimen may be further supported against lateral expansion and rupture by means of additional fixed and movable metallic reinforcing elements are well known in the art.

The pressure which may usefully be applied with apparatus of this description is limited, however, by the strength of the anvils, particularly the formed portions thereof adjacent the anvil contact surfaces which are of reduced cross section and in which are concentrated the greatest forces tending to rupture and disintegration.

It is an object of the invention to provide a high pressure apparatus of the general type in which a specimen is subjected to a very heavy pressure along one axis be- 3,374,501 Patented Mar. 26, 1968 tween two opposed anvil elements in which there is provided a novel and more eflicient means for supporting the specimen and anvils engaging therewith which will very substantially increase the resistance of these elements to rupture as a result of stresses set up by such axially directed pressures.

With the above and other objects in view as may hereinafter appear a feature of the invention consists in the provision of an anvil structure comprising a pair of op posed anvil elements each having a cylindrical base of large cross sectional area for supporting a maximum axially directed load imposed upon said high pressure press assembly, and adjacent said base converging surfaces terminating in a specimen engaging work face of relatively smaller area concentrating said axially directed thrust therein. A support cylinder having an internal cylindrical wall extends between and overlies the cylindrical base portions of said anvil elements. Fluid containing seals disposed between said internal cylindrical wall and each of said cylindrical bases provides with said support cylinder and anvil elements a pressure fluid containing enclosure. Said structure is provided in combination with means directing a pressure fluid into said enclosure so that an environmental pressure is exerted upon the included specimen and upon the included surfaces of the anvils including the anvil work faces and adjacent di verging surfaces of the anvil tip to very substantially increase the amount of the axially directed pressure which can be applied to said press assembly without risk of rupture or disintegration of the anvils and specimen.

An essential feature of the invention consists in the provision of means for controlling said environmental pressure particularly as the opposed anvil elements are moved toward one another for axially loading said high pressure apparatus.

A feature of the invention consists, also, in the method carried out with the apparatus described for subjecting a specimen to high pressures along a single press axis.

The several features of the invention will be readily understood by one skilled in the art from the following description taken in connection with the accompanying drawing in which:

FIG. 1 is a sectional view in side elevation of a high pressure apparatus embodying in a preferred form from the several features of the invention, said apparatus being adapted to be inserted between the platens of a conventional press;

FIG. 2 is a plan view but on a reduced scale of-the high pressure apparatus of FIG. 1;

FIG. 3 is a somewhat fragmentary sectional view in side elevation of the high pressure apparatus shown in FIG. 1 set up for operation upon a very thin sample sealed from contact with the surrounding high pressure supporting fluid by means of an O-ring;

FIG. 4 is a fragmentary view of the high pressure apparatus illustrated in FIG. 1 but on a smaller scale set up for operation upon a relatively long sample protected by a rubber jacket, the spherical anvil tips being composed of glass;

FIG. 5 is a sectional view of the high pressure apparatus shown in FIG. 1, in which the sample is further supported laterally by means of a tapered metallic ring of high tensile strength, a pair of O-rings being provided to protect the sample from contact with the surrounding high pressure supporting fluid; and

FIG. 6 is an enlarged fragmentary view of the O'ring and its supporting taper ring by means of which the environmental pressure is caused to act only against outer portions of the tapered support ring for the specimen.

In carrying out the invention opposed anvil assemblies of the general type having massive anvil supports and vessel adapted ,to contain 'very high pressures. While the exposed surface portions of the anvils adjacent the smaller contact surfaces in-which is concentrated the heaviest load are preferably tapered or spherical in shape to provide exposed surface contours of maximum strength, it willbe understood that anvils of other shape maybe employed.

A suitable fiuidpressure medium; for example ,oil, is

introducedinto the pressure chamber bounded byfisaid sleeve element, the massive anvil supports and high pres sure packings above describedeThe pressure fluid introduced into the pressure chamber undervery high pressure exerts an enveloping pressure upon the specimen and exposed anvil elements which very substantially increases theresistance of the specimen andanvils to rupture and disintegration induced by very high pressures exerted along the. thrust axis of the anvils. Provision is made for continuously adjustingthe enveloping fluid pressure within the pressure chamber to maintain said fluid pressure at a desired value as the anvil assemblies are moved toward one another tending to further compress the contained volume of the fluid pressure medium.

Referring more specifically to the drawing my improved high pressure apparatus comprises a pairof opposed anvil assemblies of which the upper assembly comprises a spherical anvil member mounted on a massive anvil supporting element 12 ,of substantially larger diameter than the spherical anvil member 10, and providedat its outer end with a still larger cylindrical base 14. The lower 7 anvil assembly similarly comprises a spherical anvil member 16 supported on a massive cylindrically shaped anvil support 18 of substantially greater diameter than the spherical anvil member 16 and provided at its lower end with a base 20 of still greater diameter. The two anvil assemblies are supported and are relatively movable toward and .awaylfrom each other within a very thick .walled sleeve 22,-which may be made of highly stressed steel, the

inner diameter of which-is gaugedto receive respectively the massive anvil supports 12 and 18. The sleeve member 22 together with the anvil supports 12 and 18 provide -a 1 closedpressure chamber 24 within which are mounted the anvils 10 and 16 and the specimen to be supported between the twoanvils. 1

A high pressure friction packing 26 is interposed between the internal periphery of the sleeve 22 and the engaging peripheral surfacelof the anvil support member-.12. A similar type pressure friction packing 28 is provided between the internal peripheral. surfaceof the sleeve 22 and the engaging peripheral surface of the anvil support member 18. l

A band 30 of soft steel surrounds thecylinder 22, acting as a safety device to confine the parts in the event that in the w all of cylinder 22 into the compression chamber It will be understood that the pressure apparatus above described may 'be set up for operation upon specimens which may be of many different shapes and sizes or may be composed of materials havingwidely varying physical characteristics. FIGS.'3, 4, and 5, illustratethree different ways of supporting specimens withinthe high pressure "apparatus dlSClOSfiiIIi FIG. 4- thereis'a specimen 44 cylindrical in shape and of relatively greaterheight than diameter which is positioned between the two anvils 10a and 16a which in this instance are made of a transparent material shown as glass and is protected from contact with the pressure fluid within the chamber 24 by means of a rubber or other plastically conforming sheet or jacket 46.

FIG. 3 illustrates an arrangement for applying pressure to a very thin sample 50. As shown, thesarnple is supported between the anvils 10 and 16 and is protected'from direct engagement with theenvironmental highpress ure fluid in chamber. 24 by means of an O-ring '52; This is a typical arrangement of a very thin specimen which is capable of withstanding a maximum pressure before excessive deformation and rnpturelof the specimen takes place.

FIG. 5 illustrates a still different way of supporting a sample-54 in my high pressure apparatus. In this instance a sample 54 mounted between the anvils 10 and 16 is laterally supported by means of an inwardly tapered metallic ring 56 further reinforced about its outer periphery by means of a stressed steel band 58; Two O-rings 60 and 62-are inserted respectively between the support a ing band 56-and anvil 10 and between the supporting the cylinder 22 should break down under the high internal 7 men to,.be locatedltherebetween. The fluid medium will preferably be a liquid such as oil, or glycerin and water, or alternatively a gas depending upon the requirements of the particular test or manufacturing operation being carriedout, The fluid medium is introduced from any converiient source, not shown, through an inlet conduit 36 and pump 38, from which the fluid is passed througha pressure-regulated valve 40 and a radial inlet conduit 42 band 56 and anvil 16 to protect the sample 54 from direct contact with the high pressure fluid. The O'-rings 60'and 62 are backed by tapered support rings of which one is shown at 64- in the enlarged detail sectional view-FIG. 6. The rings 64 are preferably made of brass or other suitable material which will'fiow to the extent necessary when subjected to the compressive pressure of the relatively advancing'anvilassemblies. The environmental support of the specimen 'is thus provided by the stressed ring 56 backed by the environmental pressure in the chamber 24 further amplified by the taper of thering The support provided by the environmental pressure servesalso to greatly increase the effective strength of thering assem;

In operation the apparatus is assembled with a specimerr which may, for example, be the very thin specimen 50 of FIGL 3, and the O-ring 52. The assembled high pres sure apparatus is placed between the platensr32; and. 3.34;;

of the press, and an initial thrust may be applied to establish positive contact between the anvils and the specimen sure against the exposed spherical surfaces ofthe anvils 10 and 16, the endfaces-of-the massive anyil supports 12 and 18, and against the edges of the specimeri'SO; The environmental pressure produced by thefluid pres sure medium is increased to a pointatwhich said environj; mental pressure will prevent plastic deformation; and the subsequent rupture of the anvils and specirnen,unde'r,the.. extreme pressures to which they are now subjected along, the longitudinal axis by th e compressive;mo rementlofl; the platens 32 and 34. At all times sufiicientlthrusti must be applied at the platens to. opposeandsomewhat exceed the thrust resulting from the environmental pressure. The,

force exertedatthe platens ,has two components that which is required to resist the'environmental'pressnre,

and 1 specimen.

During the compressive movement of the two anvil assemblies the environmental area 24 occupied by the fluid pressure medium becomes progressively smaller. The environmental pressure is maintained at the desired value during said compressive movements by manipulation of the regulating valve 40.

It is assumed that the anvil supports 12 and 18 are of hard steel, the spherical anvils and 16 are of a material particularly suited to the specimen and the nature of the experiment as sapphire, steel, metal carbide or other essentially hard substance, and the cylinder 22 is of stressed steel, and that the specimen 50 is to be subjected to an axial pressure in the order of one to several million pounds per square inch.

Anvil assemblies of the general type described operating at atmospheric pressure have been found to withstand axially directed pressures in the order of 1,500,000 pounds per square inch. However, when an environmental fluid pressure is introduced into the chamber 24 and is exerted upon all the exposed surfaces of the anvils 10 and 16 and adjacent exposed end faces of the massive anvil supports 12 and 18, the ability of the anvil assemblies to Withstand the axial pressure imposed thereon is greatly increased. Depending upon the amount of environmental pressure employed it is assumed that the axial pressure upon the apparatus may be safely stepped up by a factor of 1.5 to 2.5 times. When a suitable high pressure fluid is introduced into the chamber 24 at a pressure in the order of 200,000 pounds per square inch the exposed surfaces of the anvil assemblies and sample will be amply supported against plastic deformation in the presence of pressures exerted axially through the anvil assemblies sufiicient to produce the desired one to several million pounds per square inch upon the sample 50 while maintaining a reasonable margin of safety against rupture and disintegration of the apparatus.

While any improved high pressure apparatus above described is particularly adapted for subjecting specimens to very high pressures, the apparatus may be employed with advantage also under different sets of operating conditions which may involve the use of different materials, the application of lower pressures and the like. As an example, anvils of glass or quartz which are brittle and easily fractured may be employed in order to make possible the visual inspection of a specimen while under pressure. Anvils composed of such extremely brittle and easily fractured materials can be subjected to substantially higher axial pressures while supported by applicants environmental pressure than would norm-ally be considered practicable without risk of fracture or disintegration of the anvils. Visual inspection channels are provided to the glass anvil tips 10a and 1611 through central bore 68 and cross groove 70 in anvil supporting element 12 and central bore 72 and cross groove 74 in anvil supporting element 18. The electrical contact plates 76 and spring 78 illustrated for obtaining electrical measurements are removed for this purpose. The high pressure apparatus disclosed is further constructed and arranged to operate with a minimum of those expensive and hard-to-evaluate friction losses which are normally to be expected of a pressure device having moving parts subjected to pressure from different directions. The only friction loss resulting from the application of environmental pressure in the chamber 24 will be the relatively minor friction loss generated in the pressure seals 26 and 28 between the cylinder 22 and the anvil supports 12 and 18.

From the foregoing description it will be appreciated that my improved high pressure apparatus provides a simple structure which is both versatile and highly efiicient in operation and capable of operating at ultra high pressures.

The invention having been described what is claimed is:

1. A high pressure press assembly having, in combination a pair of opposed anvil elements each comprising a cylindrical base of large cross sectional area for supporting a maximum axially directed load imposed upon said high pressure press assembly, and adjacent said base converging surfaces terminating in a specimen engaging work face of relatively smaller area concentrating said axially directed load therein, a support cylinder having an internal cylindrical wall extending between and overlying each of said cylindrical bases, fluid pressure containing seals between said internal cylindrical wall and each of said cylindrical bases, providing with said support cylinder and anvil elements a pressure fluid containing enclosure, means for subjecting said anvil elements to an axially directed compressive pressure, and means directing fluid under pressure into said fluid pressure containing enclosure providing an environmental pressure of less thrust than that exerted by said axial pressure against any included specimen and exposed surfaces of said anvil elements between said seals including said converging surfaces and specimen engaging work faces.

2. A high pressure press assembly according to claim 1 in which means are provided for controlling the fluid pressure within said enclosure to establish a desired relationship of said environmental fluid pressure to axial thrust which is independent of volumetric variation of said enclosure.

3. A high pressure press assembly according to claim 2 in which a layer of plastic material overlies a said specimen between said anvil elements for protection from said pressure fluid.

4. A high pressure press assembly acording to claim 2 in which a supporting ring of high tensile strength externally fitted to a said specimen of cylindrical shape between said anvil elements provides support for said specimen radially of said axis, said ring having an internal tubular surface engaging a said sample, a peripheral surface subject to said environmental pressure, and side surfaces formed with radially diverging tapers, and a sealing ring between each said side surface and an adjacent anvil element.

5. A high pressure press assembly according to claim 2 in which the anvil elements comprise a cylindrical base of large diameter, a spherically shaped anvil tip of a smaller diameter having a flat specimen engaging work face concentrating said axially directed load therein.

6. A high pressure press assembly according to claim 2 in which at least one said anvil element is formed with an anvil tip composed of a transparent material having a specimen engaging surface of small area, and adjacent contoured surfaces connecting with said cylindrical base of large cross sectional area, and in which the supporting anvil base for said anvil tip is formed with a visual inspection channel connected between the exterior of said press assembly and said transparent anvil tip.

7. A high pressure press assembly according to claim 2 in which a supporting ring of high tensile strength is fitted to a said specimen between said anvil elements for supporting said specimen, radially of said axis, said supporting ring being located within said pressure fluid containing enclosure thereby substantially increasing the tensile strength of said ring applied to the radial support of said specimen.

References Cited UNITED STATES PATENTS 2,990,602 7/ 1961 Brandmays et al. 3,089,189 5/1963 Feldman et al. 3,123,862 3/ 1964 Levey. 3,172,153 3/1965 Loomis et al. 3,179,979 4/ 1965 Bundy et al. 3,268,951 8/ 1966 Newhall. 3,328,838 7/1967 Zeitlin.

WILLIAM J. STEPHENSON, Primary Examiner,

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