U.S. patent application number 12/330644 was filed with the patent office on 2010-06-10 for sintered diamond heat exchanger apparatus.
This patent application is currently assigned to Renewable Thermodynamics, LLC. Invention is credited to Gary P. Hoffman, Richard Ide.
Application Number | 20100139885 12/330644 |
Document ID | / |
Family ID | 42229769 |
Filed Date | 2010-06-10 |
United States Patent
Application |
20100139885 |
Kind Code |
A1 |
Hoffman; Gary P. ; et
al. |
June 10, 2010 |
SINTERED DIAMOND HEAT EXCHANGER APPARATUS
Abstract
A heat exchanging medium is provided which is constructed out of
sintered diamond. The medium can be formed into various desired
shapes such as tubes, mesh, screens, granules or the like. The
sintered diamond forms the heat transfer medium of a heat exchanger
or regenerator.
Inventors: |
Hoffman; Gary P.;
(Middlesex, NY) ; Ide; Richard; (Middlesex,
NY) |
Correspondence
Address: |
HARRIS BEACH PLLC
99 GARNSEY ROAD
PITTSFORD
NY
14534
US
|
Assignee: |
Renewable Thermodynamics,
LLC
Middlesex
NY
|
Family ID: |
42229769 |
Appl. No.: |
12/330644 |
Filed: |
December 9, 2008 |
Current U.S.
Class: |
165/7 ;
165/185 |
Current CPC
Class: |
F28D 17/02 20130101;
F28D 7/16 20130101; F02G 1/057 20130101; F28F 21/02 20130101; F28D
7/0025 20130101; F28D 7/1615 20130101; F02G 2257/00 20130101 |
Class at
Publication: |
165/7 ;
165/185 |
International
Class: |
F28D 17/00 20060101
F28D017/00; F28F 21/02 20060101 F28F021/02 |
Claims
1. A regenerator for exchanging heat energy between a reciprocating
fluid flow and a heat storage medium comprising: a housing; the
heat storage medium including a plurality of sintered diamond
elements within the housing, the plurality of sintered diamond
elements having a fluid passage therethrough; a plurality of
insulating elements within the housing and spaced between the
sintered diamond elements, the insulating elements having a fluid
passage therethrough, the fluid passage of the insulating elements
in fluid communication with the fluid passage of the sintered
diamond elements.
2. The apparatus of claim 1 wherein the sintered diamond elements
comprise irregularly shaped diamond dust particles sintered
together such that the sintered diamond elements are porous.
3. The apparatus of claim 1 wherein the sintered diamond elements
comprise a plurality of disks placed adjacent one another between
the insulating elements.
4. The apparatus of claim 1 wherein the sintered diamond elements
comprise a plurality of plates placed adjacent one another between
the insulating elements.
5. The apparatus of claim 1 wherein the sintered diamond elements
comprise a plurality of tubes placed adjacent one another between
the insulating elements.
6. The apparatus of claim 1 wherein the sintered diamond elements
are made from diamond particles of between 0.001 and 500
microns.
7. The apparatus of claim 1 wherein the sintered diamond elements
are made by placing diamond particles in a mold and heating the
particles to sufficient temperature to fuse the particles
together.
8. The apparatus of claim 7 wherein the mold has cavities shaped in
the form of wire-like mesh.
9. The apparatus of claim 7 wherein the mold has cavities shaped in
the form of tubes.
10. The apparatus of claim 1 wherein each of the sintered diamond
elements have an opening therethrough and each of the insulating
elements have an opening therethrough, and further including an
insulating material within each of the openings of the sintered
diamond elements and each of the insulating elements.
11. The apparatus of claim 10 wherein the openings in the sintered
diamond elements and the openings of the insulating elements are
substantially through the center of the sintered diamond elements
and the insulating elements.
12. A heat exchanger for exchanging heat energy between a first
fluid flow and a second fluid flow comprising: a housing; a
plurality of sintered diamond elements within the housing, the
plurality of sintered diamond elements having a first fluid passage
associated therewith and a second fluid passage associated
therewith, and the first fluid passage is isolated from the second
fluid passage.
13. The apparatus of claim 12 wherein the sintered diamond elements
comprise a plurality of tubes of sintered diamond and wherein the
first fluid passage is through the plurality of tubes and the
second fluid is between the plurality of tubes.
14. The apparatus of claim 12 wherein the sintered diamond elements
comprise a first plurality of tubes and a second plurality of tubes
the first plurality of tubes forming the first fluid passage and
the second plurality of tubes forming the second fluid passage
wherein the first plurality of tubes and the second plurality of
tubes are embedded in a block of sintered diamond.
15. The apparatus of claim 12 wherein the sintered diamond elements
are made from diamond particles of between 0.001 and 500
microns.
16. The apparatus of claim 12 wherein the sintered diamond elements
are made by placing diamond particles in a mold and heating the
particles to sufficient temperature to fuse the particles
together.
17. The apparatus of claim 12 wherein the mold has cavities in the
shape of tubes.
18. A regenerator for exchanging heat energy between a
reciprocating fluid flow and a heat storage medium comprising: a
housing; an insulating core; the heat storage medium including a
plurality of sintered diamond elements within the housing and
surrounding the insulating core, the plurality of sintered diamond
elements having a fluid passage therethrough; a plurality of
insulating elements within the housing and spaced between the
sintered diamond elements, the insulating elements having a fluid
passage therethrough, the fluid passage of the insulating elements
in fluid communication with the fluid passage of the sintered
diamond elements.
Description
TECHNICAL FIELD
[0001] The invention relates to improvements in heat transfer
materials. More particularly, this invention relates to the use of
sintered diamond material for heat exchangers and regenerators.
BACKGROUND
[0002] Heat exchangers are used in many applications including
heating units, cooling units, engines and many other applications.
For example, heat exchangers are used in Stirling engines such as
those found in, by way of example only, U.S. Pat. No. 7,076,941,
Such Stirling engines also use regenerators which are specialized
heat exchangers. Typically, such engines use heat transferring
materials in their heat exchangers and regenerators such as
aluminum, copper, brass, or stainless steel. While these heat
exchanges are adequate for some uses, an improved heat exchanger is
needed which has a higher thermal conductivity. Higher thermal
conductivity results in more efficient heat transfer and reduced
energy loss. In addition, heat transferring materials are needed
with a high thermal diffusivity for the efficient transfer of heat
energy.
[0003] There remains a need for improved heat exchangers and
regenerators which have higher thermal conductivity than heat
exchangers and regenerators of the past.
SUMMARY OF THE INVENTION
[0004] The present invention relates to the use of heat exchanging
material constructed of sintered natural or synthetic diamond
powder or particles. Synthetic diamonds have been manufactured for
over half a century. In one manufacturing process, a natural
diamond sliver is placed in a chamber under 58,000 atmospheres of
pressure at 1500 degrees Celsius. The sliver of natural diamond is
bathed in a molten solution of graphite and a catalyst. Carbon
precipitates onto the diamond sliver. Using this process, a three
carrot diamond can be grown in just a few days. Through this and
other methods, over 100 tons of synthetic diamonds are manufactured
each year. These synthetic diamonds are used for various industrial
and commercial applications. For example, synthetic diamonds are
used in drill bits, cutting blades and grinding wheels.
[0005] Diamond particles such as natural or synthetic diamond dust
are a byproduct of some of these applications and the diamond dust
is readily available in many different sizes. This dust could be a
byproduct of processes using natural or synthetic diamonds. The
sintered diamond dust can be made of particles of various sizes
from extremely fine powder to more coarse particles. For example
the diamond dust can be found from commercially available sources
in particle sizes ranging from 0.025 microns to 100 microns. For
example, diamond dust can be purchased in these size ranges from
Advanced Abrasives Corporation of Pennsauken, N.J. The cost of
diamond dust generally depends on the size of the diamond
particles, and the finer the powder, the less expensive it is.
Thus, fine powder can be used to form many desired shapes and
configurations.
[0006] Diamonds have one of the highest coefficients of thermal
conductivity of any material. Sintered diamonds have a coefficient
of thermal conductivity of nearly 8 watts/cm.degree. C., making it
an ideal heat exchanging medium. The use of irregularly shaped
particles increases the surface area of the formed or finished
sintered diamond heat exchanging material. The process of sintering
diamond involves placing the fine powder or particles in a mold.
The mold is then placed in an ultra high temperature press and
heated to a temperature in the range of 2000 degrees Fahrenheit
under a pressure in the range of hundreds of pound per square inch.
At this temperature and pressure, the diamond powder is fused
together. It is within the scope of the present invention to mix
the diamond powder with other materials such as boron carbide,
silicon carbide or other materials before sintering. As used
herein, sintered diamond can refer to pure sintered diamond, or
sintered diamond which also includes other materials mixed with the
diamond powder. The diamond could be natural or synthetic.
[0007] The sintered diamond material can be formed into many
desired shapes including tubes, screens, mesh, disks, granules, or
other possible shapes. Where necessary, passages can be formed in
the finished sintered diamond heat exchanging materials to allow
fluid to flow through. For example, if the sintered diamond is
formed into a disk, fluid passages can be formed directly in the
disk. The sintered diamond can be formed into various shapes
depending on the required application. For example, the sintered
diamond can be adapted to be used with a regenerator of a Stirling
engine. A regenerator is a temporary repository of heat during
certain cycles of the Stirling engine. Heated fluid flows through
in one direction, and heat is transferred to the regenerator
material. Relatively colder fluid flows through the regenerator in
the other direction and picks up the heat energy left behind when
the heated fluid flowed through.
[0008] In one example embodiment of the present invention, the
diamond material can be formed into circular disks resembling mesh
material. It will be understood by those of ordinary skill in the
art that the disks need not be circular, but can take many
different shapes. The material could be made into thin disks which
resemble wire mesh heat exchanging material. In this case, the
mesh-like disks would be separated by thin insulating layers (with
holes for fluid flow) that would keep heat from being conducted
from one end of the regenerator to the other. In one example
embodiment, the disks would be on the order of 1/8 inch thick.
[0009] In another embodiment, the sintered diamond material can be
formed into small, irregular pieces of sintered diamond material.
These irregular pieces can be packed into a space between
insulating disks, and the fluid flow would be between and around
these pieces.
[0010] When used for a heat exchanger, the diamond particles can be
formed into shapes having two flow passages therethrough. The use
of two sets of passages is well known in heat exchangers. As fluid
flows through one set of passages, heat is transferred to the heat
exchanger material. The heat is then transferred to the fluid
flowing through the other set of passages. The two sets of passages
are isolated from one another so that the two streams of fluid do
not mix with one another.
[0011] In one example embodiment, a regenerator includes a housing.
The housing includes a plurality of sintered diamond elements
having a fluid passage therethrough. A plurality of insulating
elements are spaced between the sintered diamond elements and also
have a fluid passage therethrough. The fluid passages of the
insulating elements are in fluid communication with the fluid
passages of the sintered diamond elements. The sintered diamond
elements can comprise irregularly shaped diamond dust particles
sintered together such that the sintered diamond elements are
porous. Alternatively, or in addition, the sintered diamond
elements can include a plurality of disks placed adjacent one
another between the insulating elements. The sintered diamond
elements can be made from diamond particles of between 0.001 and
500 microns, for example. In one example embodiment, the sintered
diamond elements are made by placing the particles in a mold and
subjecting the particles to high temperature and pressure as is
known in the diamond sintering art.
[0012] In some example embodiments, each of the sintered diamond
elements and each of the insulating elements have an opening
therethrough, for example through the center of the sintered
diamond elements and the insulating elements. Insulating material
can be placed within each of the openings of the sintered diamond
elements and each of the insulating elements.
[0013] In another example embodiment of the invention, a heat
exchanger includes a housing containing a plurality of sintered
diamond elements. The plurality of sintered diamond elements have
first and second fluid passages associated therewith which are
isolated from one another. The sintered diamond elements could be,
for example mesh constructed of sintered diamonds. Alternatively,
or in addition, the sintered diamond elements could be made as
disks of sintered diamonds having passages therethrough.
[0014] In another embodiment, the sintered diamond elements include
a plurality of tubes of sintered diamond. One fluid flow is through
the tubes and a second fluid flow is between the plurality of
tubes. In another example embodiment, the sintered diamond elements
include a first plurality of tubes and a second plurality of tubes.
The first plurality of tubes forms a first fluid passage and the
second plurality of tubes forms a second fluid passage.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Embodiments and applications of the invention are
illustrated by the attached non-limiting drawings. The attached
drawings are for purposes of illustrating the concepts of the
invention and may not be to scale.
[0016] FIG. 1 is an exploded perspective view of one embodiment of
the present invention;
[0017] FIG. 2 is another exploded perspective view of the invention
of FIG. 1;
[0018] FIG. 3 is a perspective view of another embodiment of the
present invention;
[0019] FIG. 4 is a front elevation view of the invention of FIG.
3;
[0020] FIG. 5 is a perspective view of another embodiment of the
present invention;
[0021] FIG. 6 is an end view of another embodiment of the present
invention;
[0022] FIG. 7 is a front elevation view of the invention of FIG.
6;
[0023] FIG. 8 is a cross-sectional view of another embodiment of
the present invention;
[0024] FIG. 9 is a cross-sectional view of another embodiment of
the present invention;
[0025] FIG. 10 is a cross-sectional view of another embodiment of
the present invention;
[0026] FIG. 11 is an end view of the invention of FIG. 10;
[0027] FIG. 12 is an end view of another embodiment of the present
invention;
[0028] FIG. 13 is a cross-sectional view of the invention of FIG.
12;
[0029] FIG. 14 is an end view of another embodiment of the present
invention;
[0030] FIG. 15 is a cross-sectional view of the invention of FIG.
14;
[0031] FIG. 16 is a simplified representation of a sintered diamond
molding apparatus;
[0032] FIG. 17 is a simplified representation of a sintered diamond
top mold;
[0033] FIG. 18 is a simplified representation of a sintered diamond
bottom mold;
[0034] FIG. 19 is a simplified representation of another sintered
diamond top mold;
[0035] FIG. 20 is a simplified representation of another sintered
diamond bottom mold;
[0036] FIG. 21 is a simplified representation of a side
cross-sectional view of sintered diamond top and bottom molds shown
separated from one another;
[0037] FIG. 22 is a simplified representation of a side
cross-sectional view of sintered diamond top and bottom molds shown
together;
[0038] FIG. 23 is a simplified representation of a side
cross-sectional view of sintered diamond tubes after molding has
taken place; and
[0039] FIG. 24 is a simplified representation of the process of
molding sintered diamond.
DETAILED DESCRIPTION
[0040] Throughout the following description specific details are
presented to provide a more thorough understanding to persons
skilled in the art. However, well-known elements may not have been
shown or described in detail to avoid unnecessarily obscuring the
disclosure. Accordingly, the description and drawings are to be
regarded in an illustrative, rather than a restrictive, sense.
[0041] FIGS. 1 through 11 illustrate various embodiments of the
present invention. Referring to FIGS. 1 and 2, an exploded view of
a heat exchanger 10 illustrating one embodiment of the present
invention is shown. The heat exchanger 10 includes a housing 12.
The housing 12 is shown as cubic in configuration for illustration
purposes only. It will be understood by those skilled in the art
that the housing 12 can be made in many possible shapes. The
housing 12 has walls 14, 16, 18 and 20, shown again in the
particular configuration for illustration purposes. Sintered
diamond tubes 22 are placed within the housing 12. The length and
diameter of sintered diamond tubes 22 are a matter of design
choice, depending on the heat transfer and flow and pressure and
temperature requirements for a particular application. The tubes 22
are held in position by faceplates 24 and 26 which have holes 28
through which the tubes 22 extend. Fluid (not shown) can flow
through the tubes 22 in the direction of arrow 30. Walls 14 and 18
have fluid holes 32 and 34 respectively. Fluid can flow into and
out of holes 32 and 34 in the direction of arrow 36. As fluid flows
through tubes 22, heat is transferred to or from the tubes 22. A
second isolated fluid flow through holes 32 and 34 travels around
and between tubes 22. This fluid flow either picks up or delivers
heat to the tubes 22 depending on the relative temperatures of the
fluid flowing within and around the tubes 22. Because the tubes 22
are made of sintered diamond, a highly efficient heat exchanger is
created.
[0042] FIGS. 3 and 4 show another example embodiment of a heat
exchanger 50. A housing 52 is shown as cubic in configuration for
illustration purposes only. The housing 52 can be made in many
possible shapes. The housing 52 has walls 54, 56, 58, and 60, again
shown in the particular configuration for illustration purposes.
Sintered diamond tubes 62 are placed within the housing 52. The
length and diameter of sintered diamond tubes 62 are a matter of
design choice, depending on the heat transfer requirements for a
particular application. The tubes 62 are held in position by walls
56 and 60 which have holes 68 through which the tubes 62 extend.
Fluid (not shown) can flow through the tubes 62 in the direction of
arrow 70. Ends 74 and 78 have fluid holes 82 and 84 respectively.
Fluid can flow into and out of holes 82 and 84. As fluid flows
through tubes 62, heat is transferred to or from the tubes 62. A
second isolated fluid flow through holes 82 and 84 travels around
and between tubes 62. This fluid flow either picks up or delivers
heat to the tubes 62 depending on the relative temperatures of the
fluid flowing through and around the tubes 62.
[0043] FIG. 5 shows another example embodiment of a heat exchanger
150. A housing 152 is shown as cubic in configuration for
illustration purposes only. It will be understood by those of skill
in the art that the housing 152 can be made in many possible
shapes. The housing 152 has walls 154, 156, 158 and 160, shown
again in the particular configuration for illustration purposes.
Sintered diamond tubes 162 and 163 are placed within the housing
152. The length and diameter of sintered diamond tubes 162 and 163
are a matter of design choice. The tubes 162 are held in position
by walls 156 and 160 which have bores 168 through which the tubes
162 extend. Similarly, tubes 163 extend through ends 174 and 178
which have bores 169 therethrough. Fluid (not shown) can flow
through the tubes 162 in the direction of arrow 170. A second,
isolated flow of fluid flows through tubes 163 in the direction of
arrow 171. If the fluid flowing through tubes 162 has a higher
temperature than the fluid flowing through tubes 163, heat is
transferred to the fluid flowing through tubes 163. If the fluid
flowing through tubes 163 has a higher temperature than the fluid
flowing through the tubes 162, heat is transferred to the fluid
flowing through tubes 162. Because the tubes 162 and 163 and the
housing are made of sintered diamond, the heat is transferred very
efficiently.
[0044] FIGS. 6 and 7 illustrate a regenerator 210 in accordance
with an example embodiment of the present invention. It will be
understood by those of skill in the art that the particular
configuration of the regenerator 210 is shown for illustration
purposes only and that various other configurations of the
regenerator are possible. An outer housing 212 is provided with
flanges 214 and 216. Depending on the particular application, the
housing could be made from metal, such as, for example, aluminum,
brass, or steel. In this example embodiment, the flanges 214 and
216 include bolt holes 218 for attaching the regenerator 210 to
other parts of a system. The regenerator 210 includes an insulating
layer 220 made of any suitable insulating material. The choice of
insulating material will depend on the application in which the
regenerator 210 is used and could include a polymer or ceramic
material for example. A sintered diamond heat exchanging medium 230
is provided. In this illustrated embodiment, the sintered diamond
heat exchanging medium 230 is shown as a series of rings 232. The
rings 232 are separated by insulating material 234 to prevent heat
transfer in the direction of fluid flow illustrated by line 240.
Because the sintered diamond heat exchanging medium 230 has such a
high coefficient of thermal conductivity, heat would rapidly spread
from one end 242 of the regenerator 210 to the opposite end 244
without insulating material 234. The sintered diamond heat
exchanging medium 230 and the insulating material 234 are porous
such that fluid (not shown) can flow in the direction of line 240.
As is known to those of skill in the art, a regenerator works by
heated fluid flowing in one direction, for example direction 240A.
The heated fluid flows through the sintered diamond heat exchanging
medium 230 and transfers its heat to the sintered diamond heat
exchanging medium 230. In another cycle, relatively cooler fluid
flows in the direction 240B. The relatively hotter sintered diamond
heat exchanging medium transfers heat to the cooler fluid flowing
in direction 240B. In some applications, an insulating core 250 is
provided such that the diameter of the regenerator matches other
components in the system without providing excess regeneration
capacity.
[0045] FIG. 8 illustrates another embodiment of a regenerator 310
using sintered diamond heat exchanging medium 330. An outer housing
312 is provided with flanges 314 and 316. Again, depending on the
particular application, the housing could be made from, for
example, metal, such as aluminum, brass, or steel. The regenerator
310 includes an insulating layer 320 made of any suitable
insulating material. The choice of insulating material will depend
on the application in which the regenerator 310 is used and could
include a polymer or ceramic material for example. A sintered
diamond heat exchanging medium 330 is provided. In this illustrated
embodiment, the sintered diamond heat exchanging medium 330 is
shown as a quantity of granules 332 packed between insulating
material 334 to prevent heat transfer in the direction of fluid
flow illustrated by line 340. The granules 332 are sized such that
spaces 336 are present between granules 332. The spaces 336 allow
for fluid to flow between and around the granules 332. The
insulating material 334 is porous to allow fluid to flow through
the insulating material 334. An insulating core 350 is provided for
use in some applications.
[0046] FIG. 9 illustrates another embodiment of a regenerator 410
in accordance with an example embodiment of the present invention.
An outer housing 412 is provided with flanges 414 and 416. The
regenerator 410 includes an insulating layer 420 made of any
suitable insulating material. A sintered diamond heat exchanging
medium 430 is provided. In this illustrated embodiment, the
sintered diamond heat exchanging medium 430 is shown as
multilayered sintered diamond mesh 432. The mesh 432 is separated
by insulating material 434 to prevent heat transfer in the
direction of fluid flow illustrated by line 440. Because the
sintered diamond heat exchanging medium 430 has such a high
coefficient of thermal conductivity, heat would rapidly spread from
one end 442 of the regenerator 410 to the opposite end 444 without
insulating material 434. An insulating core 450 is provided to
adjust the capacity of the regenerator 410.
[0047] FIGS. 10 and 11 illustrate another embodiment of a
regenerator 510 in accordance with an example embodiment of the
present invention. An outer housing 512 is provided with flanges
514 and 516. The regenerator 510 includes an insulating layer 520
made of any suitable insulating material. A sintered diamond heat
exchanging medium 530 is provided. In this illustrated embodiment,
the sintered diamond heat exchanging medium 530 is shown as
sintered diamond wire-like mesh 532. The wire-like mesh 532 is
separated by insulating material 534 to prevent heat transfer in
the direction of fluid flow illustrated by line 540. An insulating
core 550 is provided if needed for the particular application.
[0048] FIGS. 12 and 13 illustrate another embodiment of a
regenerator 610 in accordance with an example embodiment of the
present invention. An outer housing 612 is provided to house the
internal components of the regenerator 610. The regenerator 610
includes a sintered diamond heat exchanging medium 630. In this
illustrated embodiment, the sintered diamond heat exchanging medium
630 is shown as sintered diamond tubes 632. Sections of tubes 632
can be separated by insulating material (not shown) such as
fiberglass insulation material, or other insulating material, to
prevent heat transfer in the direction of fluid flow illustrated by
line 640. Fluid flows through the tubes 632 and through the
insulating material from one end of the regenerator 610 to the
other, as will be readily appreciated by one of ordinary skill in
the art.
[0049] FIGS. 14 and 15 illustrate another embodiment of a
regenerator 710 in accordance with an example embodiment of the
present invention. An outer housing 712 is provided to house the
internal components of the regenerator 710. The regenerator 710
includes a sintered diamond heat exchanging medium 730. In this
illustrated embodiment, the sintered diamond heat exchanging medium
730 is shown as a sintered diamond spiral 732. Sections of the
spiral 732 can be separated by insulating material (not shown) such
as fiberglass insulation material, or other insulating material, to
prevent heat transfer in the direction of fluid flow illustrated by
line 740. Fluid flows through the sections of the spiral 732 and
through the insulating material from one end of the regenerator 710
to the other, as will also be readily appreciated by those of skill
in the art.
[0050] FIG. 16 is a simplified representation of a sintered diamond
molding apparatus 810. The molding apparatus 810 includes a top
mold 812 mounted to a plate 813 and a bottom mold 814 mounted to a
plate 815, which is in turn mounted to a base 824. The apparatus
includes a means 820 for pressing the top mold 812 and the bottom
mold 814 together, shown for representation purposes only as
actuated by a handle 816. Those of ordinary skill in the art will
readily appreciate that the pressures required to sinter the
diamond are much greater than can be produced by hand. A heat
source 818 is also provided for the sintering process. Again, those
of ordinary skill in the art will readily appreciate that the
temperatures required for the process will necessitate a much more
complex heating system than the one illustrated. In concept, the
diamond material (not shown) is placed in the bottom mold 814, and
the top mold 812 and the bottom mold 814 are brought together under
pressure. The top mold 812 and bottom mold 814 are heated by the
heat source 818 to sinter the diamond material.
[0051] FIGS. 17 and 18 illustrate the top mold 812 and the bottom
mold 814. The top mold 812 has pins 830. The bottom mold has
cylindrical cavities 832. The difference between the outside
diameter of the pins and the inside diameter of the cavities
determines the wall thickness of the sintered diamond tubes created
by the molds 812 and 814.
[0052] FIGS. 19 and 20 illustrate another embodiment of a top mold
912 and a bottom mold 914. The top mold 912 has pins 930. The
bottom mold has cavities 932 in the shape of wire mesh. The
difference between the size of the pins 930 and the size of the
cavities 932 determines the wire size of the sintered diamond mesh
created by the molds 912 and 914.
[0053] FIGS. 21 through 23 illustrate a schematic representation of
a cross-section of molds 812 and 814 of the present invention. The
top mold 812 has pins 830. The bottom mold 814 has cylindrical
cavities 832. The pins 830 are sized to fit within the cavities 832
such that tubes 834 are created after the sintering process. FIG.
21 illustrates the top mold 812 separated from the bottom mold 814.
FIG. 22 illustrates the top mold 812 nested inside the bottom mold
814. FIG. 23 illustrates the bottom mold 814 with the top mold 812
removed and the tubes 834 formed in the cavities 832.
[0054] FIG. 24 represents a schematic of the molding process.
Sintered diamond dust 870 and optionally a binding agent 872 are
mixed using a mixing process represented by cylinder 874. The
blended material 876 is injected into a bottom mold 878 through an
injection molding apparatus 880. The top mold 882 is forced down
into the bottom mold 878 and the blended material 876 is heated
while the pressure is applied. This sintering process is well known
in the art.
[0055] It is to be understood that the exemplary embodiments are
merely illustrative of the present invention and that many
variations of the above-described embodiments can be devised by one
skilled in the art without departing from the scope of the
invention.
* * * * *