US3191231A

US3191231A - High pressure high temperature punch member

Info

Publication number: US3191231A
Application number: US268096A
Authority: US
Inventors: Jr Robert H Wentorf
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1963-03-26
Filing date: 1963-03-26
Publication date: 1965-06-29
Anticipated expiration: 1982-06-29

Description

June 29, 1965 WENTQRF, JR 3,191,231

HIGH PRESSURE HIGH TEMPERATURE PUNCH MEMBER Filed March 26, 1963 [r7 ve 7'? to r-: Robert H WentorFJr-j aflM miizme United States Patent 3,191,231 HIGH PRESSURE HIGH TEMPERATURE PUNCH MEMBER Robert H. Wentorf, Jr., Schenectady, N.Y., assignor to General Electric Company, a corporation of New York Filed Mar. 26, 1963, Ser. No. 268,096 2 Claims. (CI. 1816) This invention relates to a high pressure, high temperature apparatus punch member and more particularly to such a punch member having a very hard material nib projection on the working end or face thereof. In general, high pressure high temperature apparatuses utilize a plurality of pressure resisting members, one or more of which move towards another to define a reaction chamber in which a specimen material is placed to be subjected to high pressures and high temperatures. The ends of these pressure resisting members are subjected to extreme temperatures and pressures and thus to critical stresses which cause many failures to occur at the very ends of the punch members. These failures usuually encompass only a very small portion of the end area and volume. Such a small failure yet results in the necessity of replacing the entire punch assembly which is usually of a very high strength, high cost, and difficultto-work material.

Accordingly, it is an object of this invention to provide an improved punch member.

It is another object of this invention to provide a high pressure high temperature punch member with a separable end portion.

- It is another object of this invention to provide a nib projection on the tip of a high pressure high temperature punch member.

It is another object of this invention to provide a refractory nib projection on the end of a high pressure high temperature punch member.

Briefly described this invention includes a refractory nib projection on the end of a tapered, hard metal punch member, which follows the general contour of the tapered punch member and extends the punch face to a new face on the nib projection which is of smaller cross sectional area than the face of the hard metal punch member.

This invention will be better understood when taken in connection with the following description and the drawing in which:

FIG. 1 is an illustration of the nib member of this invention as applied to a punch member having tapered and arcuate surfaces;

FIG. 2 is an illustration of a nib member according to the practices of this invention when applied to a punch member of generally angular cross section; and

FIG. 3 is an illustration of one use of nib members between a plurality of lateral punches.

Two general types of high pressure high temperature apparatuses to which this invention is particularly applicable are disclosed in US Patents 2,941,248Ha1l and 3,107,395-Bundy, assigned to the same assignee as the present invention. The belt apparatus disclosed in the aforementioned Hall patent, comprises in one embodiment, a pair of oppositely positioned frustoconical punch members which move into a convergent divergent opening in an intermediate concentrically positioned die or belt member. A specimen material in the die member and between the punches is compressed by motion of the punches towards each other.

The apparatus disclosed in the aforementioned Bundy patent comprises a reaction chamber defined by the smaller end faces of a plurality of trapezoidal punch members, for example six, all of which move towards a defined center and interfit with each other to define a 3,191,231 Patented June 29, 1965 Led reaction chamber. A specimen material is placed in the reaction vessel to be subjected to high pressures and high temperatures. A ceramic or stone material gasket is employed in these apparatuses between all punches, where applicable, and between the punches and the belt or die in the belt apparatus.

In either of the above described apparatus, the punch faces, i.e., the inner faces which define the walls of the reaction vessel, are subjected to the highest pressures, the highest temperatures, and the highest critical stresses. It is thus an important practice that thermal insulation, in the form of ceramic or stone gasketing, be employed between the punch face and the center of the reaction vessel in order to shield the punch face from the high temperatures in the reaction vessel. It is also an important feature and a matter of standard practice to enclose the side surfaces of the punch members with ceramic or stone gasket materials to adequately support the punch face. In most instances this practice is included in the use of gasketing between punches or between punches and confining members.

Under the conditions of high pressures and high temperatures, even such materials as the cemented tungsten carbides become somewhat plastic and are subject to failure. These failures are usually evidenced by cracks in the punch face or by small sections of the punch face breaking off. One cause of such failures is loss of lateral support at the punch face which exerts extraordinarily high forces on the punch causing a material flow and failure. A primary contributing factor to these failures is the exposure of the punches to the very high temperatures in the sample which substantially weakens the punch material. Severe limitations are imposed on the distance from the punch to the specimen because, for example, added materials diminish pressure generation ability of the apparatus or contribute prohibitive gasketing problems.

It has been discovered that a small nib of a refractory material, for example alumina, cubic boron nitride, beryllia, or zirconia may be attached to the punch faces and positioned between the punch faces and the specimen or the reaction vessel. The nib is more resistant to high temperatures while at the same time replaces gasket or reaction vessel material to provide higher pressures with less stroke or punch travel. However, where very high temperatures are not a problem or are not utilized, the nib of this invention may be metallic. In any event the use of nibs precludes the necessity of replacing the entire punch member in those very high pressure high temperature operations where punch breakage is common. Cermet materials may also be utilized for these nibs.

On particular example of the practice of this invention is illustrated in FIG. 1. Referring now to FIG. 1, there is illustrated a punch member 10 such as shown in the aforementioned Hall patent. Punch member 10 comprises a cylindrical base structure 11 and a tapered or frustoconical portion 12 extending from the base 11. Nib 13, in accordance with the practice of this invention, is placed on the face 14 of punch 10. This nib portion 13 includes a side surface 15 which is smoothly integrated with the contour of punch portion 12. Surface 15 follows the same projecting pattern of punch portion 12 to provide a face portion 16 which is smaller than face portion 14- of punch portion 12. For example, a frustoconical punch includes, preferably, a frustoconical nib where the nib is a graphical projection of the frustoconical configuration of the punch. The side surface of the nib may, however, be a smooth curve tangentially engaging the outline curve of the tapered surface of the punch.

The longitudinal extension of the thickness .of such a nib 13 is restricted to be as small as possible commen- 3 surate with the axial dimension of ordinary tip failures of the punches. The thickness must be maintained of a minimal dimension because the refractory material needs more support by way of gasket materials to maintain a structural integrity thanldo the hard steels and cemented carbidesof' which the punch members are usually rnade. Accordingly the nib projection must be con- 7(4) The nib material receives the brunt of thesevere tinually supported over its entire thickness. In a belt type apparatus, the effective gasketing between the punch and die member must. extend along the punch and die members a distance greater'than the extension or thickness of the nib. The same practice is true of interfitting punch assemblies where the gasket therebetween must be axially longer than the thickness of the nib.

In FIG. 2, there is shown a prism or trapezoidal punch 20 wherein a small nib 2:1 is positioned on the face 22 of punch 20 as an extension'thereof. Nib 21 defines a face portion 23 smaller than face portion 22 of punch 20. The purposes for which nib 21 is employed are the same as those described for'FIG. 1.

FlG. 3 illustrates four

punches

24,25, 26, and 27 (each similar to punch 20 of FIG. 2), circumferentially arranged .to define a reaction chamber or zone 28.. In

(3) For a given reaction zone pressure, the total length of the gasket is increased over that ordinarily used. Thus, the average pressure on the gradient in the gasket is reduced and the local stresses on the punches are also reduced.

. stress and thermal-gradients. However, they are small, I economical, and easily replaced.

In the practices of this invention, the nibs are usually employed'by being fastened to the corresponding faces of the punches. Such fastening, however, should not take the form of any opening in the nib or in the punch such as for bolts, attac'hing flanges, etc. The use of the nibs in this invention has'been limited to semipermanent attaching means in the form of various glues and cements, such as rubber glues, epoxy resin, etc., which do not impose any undue stress concentrations on either the nib or the punch through any materi'alremoval.

a 6-punch assembly, as disclosed in the aforementioned:

gaskets may terminate at the end of the nib, or, as illustrated, may extend furthertowards the reaction zone to define the walls of the zone. In the latter instance, further

thermal insulators

37, 38, 39, and 40 are employed at the ends of the nibs as filler elements. i

- Particular advantages of the. use of sucha nib in the practice of this invention are:

(1) Relatively compressible insulating. stone materialis replaced by rather incompressible nib material so that the punches need not travellas far to producehighi pressure in the reaction zone, and thus the demands upon the ga'sketing material are less severe. (2) The nibs aid in concentrating the force from the punchface to the reaction zone, after the manner of a tapered punch so that the pressure is'higher at the 7 nib face in the reaction zone than on the punch face. Because the nibs are exposed to high pressure on all sides, their strength and ductility, insofar as their refractory material is concerned, are improved, and relatively brittle but high strength refractory materials can be used' for the nibs..

Whilev a specific method and apparatus in accordance with this invention is described and shown, it is not intended that the invention be limited to theparticular description nor to v the' particular configurations illustrated, and it is intended by theappended claims to cover all modifications within the spirit and scope of this.

invention. i a

What I claim as new and desire to secure by Letters Patent of the UnitedStates is: v

,1. 'In a high'pressure apparatus wherein a plurality of punches are arranged in opposed relationship with suitable gasket material contiguous with each punch Wherebymovement of'atleast one punch causes compression of the gasket material andtransmits high pressure toa closed reaction vessel, the improvement comprising:

' (a) a nib positioned on and extendingfrom the distal end-.of each ofsaid'punches inwardly toward the IClOSGd reaction chamber, I

' (1) each of said ni'b's'being harder than the-ina- V terial,comprising saidpunches'and thebase area of each -n ib;being sim ilar to andin mating relationship with the face offthe distal end of its respective pun-chf j j 2. The improvement substantially as recited in claim wherein each nib is composed of refract'ory' material.

" 3,096,862 -6/6 3 Gerard et al.

3,096,544 7/63 Lundblad. 7. 3,118,177 1/64 Von Platen 18-5 WILLIAMl I. STEPHENSON, Primar Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,191,231 June 29, 1965 Robert H. Wentorf, Jr.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 4, line 39, strike out "and the" and insert instead each nib tapering from a line 40, strike out "of each nib being"; line 42, after "punch" insert to a terminal face having an area smaller than said base area Signed and sealed this 21st day of December 1965.

(SEAL) Attest:

ERNEST W. SW'IDER EDWARD J. BRENNER Attesting Officer Commissioner of Patents

Claims

1. IN A HIGH PRESSURE APPARATUS WHEREIN A PLURALITY OF PUNCHES ARE ARRANGED IN OPPOSED RELATIONSHIP WITH SUITABLE GASKET MATERIAL CONTIGUOUS WITH EACH PUNCH WHEREBY MOVEMENT OF AT LEAST ONE PUNCH CAUSES COMPRESSION OF THE GASKET MATERIAL AND TRANSMITS HIGH PRESSURE TO A CLOSED REACTION VESSEL, THE IMPROVEMENT COMPRISING: (A) A NIB POSITIONED ON AND EXTENDING FROM THE DISTAL END OF EACH OF SAID PUNCHES INWARDLY TOWARD THE CLOSED REACTION CHAMBER, (1) EACH OF SAID NIBS BEING HARDER THAN THE MATERIAL COMPRISING SAID PUNCHES AND THE BASE AREA OF EACH NIB BEING SIMILAR TO AND IN MATING RELATIONSHIP WITH THE FACE OF THE DISTAL END OF ITS RESPECTIVE PUNCH.