Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates to an ultrahigh pre-
ssure apparatus, particularly to improvements in such appar-
atus invented by the Inventor in use of a hollow cylinder made
of a rigid material with a small compressibility coefficient.
It is desired generally in works under high pressure
to increase the length of a reaction chamber arranged in such
apparatus, axially as well as radially for enlarged amount of
reaction charges per run, or for widened reaction zone which
has favorable temperature conditions for reaction.
But increasing the axial length of the reaction cham-
ber disadvantageously results in an increased thickness at seal-
ing part of gaskets, which are placed in a high pressure cham-
ber, or a space surrounded by the punches and the die. Since
the sealing ability of gaskets decreases in inverse proportion
to their thickness and increases in proportion to the length
of the sealing part, it is necessary that such decrease caused
; by the increased thickness, be set off by increasing the length.
It is also desired for a large scale high pressure
apparatus that members should be made of some kind of strong
steels, high speed steel or die steel, for example, for
reasonable manufacturing.
A dle so made suffers in general from plastic deforma-
tions much or less caused at the inner wall after several repeat-
ed runs even in use of a hollow cylinder for reducing the
stress transmitted to the die. Thus reformation are required
of the die for a tight contact of the hollow cylinder with the
die, by cutting or grinding away such deformations at an inter-
val for a smooth surface of the inner wall. And such reforma-
tion should be made on all the surface of the inner wall of
the die. Further the press load to be applied should be re-
determined due to the changes in compressing section by
reformation, and modification is also required of dimensions
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of elements for reaction.
The present invention is broadly defined as an ultra-
high pressure apparatus for diamond synthesis or the like which
comprises: a pair of opposed frusto-conical punches with a
flat end surface; an annular die made of steel and placed
between the punches, which die has a cylindrical aperture co-
axially arranged with the punches; a hollow cylinder made of
sintered alumina to be free of pores having an inner diameter
substantially equal to the diameter of the flat end surface;
a pair of gaskets adjacent to each outer portion of the inner
wall of the die and has an inner diameter same with that of
the hollow cylinder and a larger outer diameter than that of
the latter; the die having at the middle portion thereof a
substantially concentric cylindrical projection of an axial
length equal to that of the hollow cylinder so that the bore
is tightly fitted to the gaskets and the hollow cylinder.
In a specific aspect of the invention, a metal collar
generally adjacent to the said hollow cylinder is inserted
between facing walls of the die and said cylinder. In a
further specific aspect of the invention the collar is formed
of several sections.
This invention is to proyide an ultrahigh pressure
apparatus of an industrial scale which is well workable and
free from the above said problems.
The features and advantages of the invention will
be better understood from the following description, taken
in connection with the accompanying drawing, in which:
Figure 1 is an elevational section view of the main
part of a conventional ultrahigh pressure apparatus in use
of the hollow cylinder;
Figure 2 is an elevational view of the main part
of an apparatus embodying this invention which shows its
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section;
Figure 3 is an elevational sectional view of the
main part of one of the most preferred embodiment of the
invention;
Figure 4 is an elevational sectional view of the
main part of another embodiment of the invention; and
Figure 5 is a horizontal sectional view of the
embodiment in Figure 4 as exploded at A-A, showing only a
me'cal collar, a hollow cylinder, a reaction chamber and a
refractory tube surrounding the chamber.
In Figure 1, an annular die (3) of a steel, such
as die steel or high speed steel, is placed between a pair
of opposed punches ~1, 2), which are made of a very hard
alloy such as a sintered WC-Co alloy. Adjacent to the inner
wall of the die (3) is placed a hollow cylinder (4), made
of alumina sintered to be almost free from pores. A refractory
. .
tube (5) surrounds a reaction chamber (6), and tablets ~7, 8)
are for thermal and electric insulation and are made of a
rigidly fired refractory. For electric conductance steel rings
20 (9, 10) and terminal plates (11, 12) are arranged. Gaskets
(13, 14) are of a sintered aggalmatoric stone.
Of Figures 2, 3 and 4, which illustrate some embodi-
ments of the invention, Figure 2 exemplifies an arrangement
for a comparatively small apparatus in use of a hollow cylinder
which has a smaller outer diameter. Figures 3 and 4 are for
a comparatively large apparatus in use of such cylinder which
has a larger outer diameter.
The arrangement in Figure 3 or 4 shows a hollow
cylinder with tapered ends facing to the flank or punches.
The tapered ends are provided on the cylinder for increasing
a stress support for the cylinder against the deformation
under high pressures generated in a reaction chamber; for
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improving the sealing ability of gaskets for the pressures,
by reducing its gradients within the gaskets adjacent to the
flank of punches; and for protection of punches from breakup.
In Figures 2 to 4, an annular die (17), made of a
steel such as die steel or high speed steel, is placed between
and coaxially with a pair of opposed punches (15, 16), which
are made of a sintered WC-Co alloy. Adjacent to the inner
wall of the die (17) is placed a hollow cylinder (18), which
is made of alumina sintered to be almost free from pores.
A refractory tube (19~ surrounds a reaction chamber (20).
Tablets (21, 22) of a rigidly fired refractory are arranged
for tllermal and electric insulation, and steel rings (23, 24)
and terminal plates (25, 26) are for electric conductance.
Gaskets ~27, 28) are a sintered aggalmatoric stone, by material.
The punches (15, 16) have a protector ~29, 30) on them in the
arrangement of Figures 3 and 4.
For numeric example, with reference to the arrange-
ment of Figure 2, the punches have a flat end of 20 mm by
diameter, and are axially tapered at 33. The die has a
stepped aperture of 30 mm and 34 mm by diameter at the por-
tions adjacent to the hollow cylinder and to the gaskets, res-
pectively. The cylinder is 20 mm by inner diameter and 10 mm
high. Gaskets, larger in outer diameter than the cylinder of
sintered alumina, are placed adjacent to the inner wall of
a die.
Figure 5 illustrates a section of the arrangement
in Figure 4, as exploded at A-A, showing only a metal collar,
a reaction chamber, and a refractory tube that surrounds
such chamber. In this figure, such collar are formed of
four quarter-circles (31a~d), while in Figure 4 it is inte-
grally formed.
Referring to the arrangement in Figure 3, the
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punches have a flat end 75 mm across and axially tapered at
36. The die has a stepped aperture, which is 165 mm and
185 mm by inner diameter at the portions adjacent to the
cylinder and to the gaskets, respectively. The cylinder is
100 mm high and 75 mm by inner diameter. The protectors for
punches are a mild steel plate whic'n is about 2 mm thick,
and are tightly placed on them.
In a numeric example of the arrangement shown in
Figure 4, the punches have a flat end 75 mm across and are
axially tapered at 36. The die has a stepped aperture, and
is 165 mm and 185 mm by inner diameter at the portions adjacent
to the hollow cylinder and to the gaskets, respectively. The
cylinder is 100 mm high and is 75 mm by inner diameter. The
protectors for the punches are a mild steel plate about 2 mm
thick and are tightly placed on them. The larger end of pro-
tectors has a diameter larger than the aperture of the die in
each of Figures 3 and 4 and according to any embodiment of
this invention, the gaskets larger in outer diameter than the
hollow cylinder of sintered alumina, are placed adjacent to
t'ne inner wall of the die.
As might be understood from the above description
about some embodiments of the invention with reference to
the drawing, the apparatus according to this invention has per-
mitted of several functions and advantages to conventional
ones, by using gaskets which are larger in outer diameter
than the hollow cylinder and are placed adjacent to the inner
wall of the die at the enlarged portion.
According to this invention, gaskets, larger in
outer diameter than the hollow cylinder, are used adjacent
to the end portions of the inner wall of the die.
With an increased length of the sealing portion
as compared with conventional apparatus, this invention has
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permitted to use sufficiently thick gaskets for extending the
height of a reaction chamber and for increasing compressive
strokes, thus improving in yields per run.
Conventionally it has been required to increase press
loads for compression according to the enlargement of the aper-
ture caused by reformation. While, this invention has permitted
of stable works in use of unchanged press loads, regardless of
such enlar $ent of the aperture at the portion adjacent to the
hollow cylinder, for, since the inner diameter of the die
remains unchanged at the shoulder, the compressive forces are
divided at a substantially unchanged ratio for materials of
the reaction chamber from the flat ends of punches and for the
hollow cylinder through gaskets from the flanks of punches.
Conventionally it has been further required to modify
the dimension of gaskets in outer diameter to fit an enlarged
i aperture of the die. Such modification is unnecessary accord-
ing to this invention, and each element for reaction is very
simply machined and manufactured.
Quick reformation is attainable of the die according
to the invention, since such reformation is required only at
the portion adjacent to the hollow cylinder, while, in contrast,
reformation has been required from end to end of the inner
wall of a conventional die.
In placing elements for reaction within the aperture
of a die, they are readily positioned according to the inven-
tion, since the cylindrical projection of a die is axially
as long as a hollow cylinder adjacent to it.
An apparatus embodying the invention, in which a
metal collar is used adjacent to the facing walls of a die
and a hollow cylinder of an axial length,has an extended life
as compared with conventional ones out of use of such collar,
for, since such collar can be taken out of the die for exchange,
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the die remains workable even when the collar gets unsuitable
for use due to enlarged aperture by reformation or due to break-
up after repeated runs.
When the collar is formed of several sections, damaged
ones alone are required to be taken out for exhange, thus
reducing compensation of expensive collar.
In comparison of workabilities in use of apparatus
conventionally designed and according to this invention,
both comprising an annular die which is 165 mm by inner dia-
meter, reaction charges were treated according to the invention,
twice as much as the conventional one could, with requirement
of press load larger than the latter by about 10%. No differ-
ence was appreciated in lives of the dies.
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