In such fields as road milling, mining and trenching, superhard materials, such as polycrystalline diamond, may be used to breakup tough materials such as asphalt, concrete and rock. High-pressure high-temperature (“HPHT”) presses are commonly employed to create such superhard materials. While HPHT presses have been made in a variety of styles over the years, many HPHT presses comprise a plurality of piston assemblies that may act in concert to pressurize a cell. One example of such an HPHT press is disclosed in U.S. Pat. No. 6,336,802 to Hall which describes a press with a frame comprising intersecting boreholes with means for attachment of a plurality of cartridges. Each cartridge may comprise a piston therein with an anvil protruding there from into a cavity resulting from an intersection of the boreholes. Advancement of the anvils toward a center of the cavity may enclose and define a high-pressure chamber within the press.
A cell may be disposed within such a high-pressure chamber comprising the raw components required to form superhard materials. One example of raw components capable of forming a superhard material comprises diamond grains disposed within a metal canister adjacent a carbide substrate. The carbide substrate may comprise a catalyst that may sweep into the diamond grains under certain HPHT conditions to aid in sintering the diamond grains together. One or more such canisters may be surrounded by a pressure-transferring medium, such as pyrophyllite, that may form a pressure sealing gasket within gaps between adjacent anvils as well as balance pressure around the canisters. Electrically resistive materials may also be disposed within such cells that may heat the cells to desired temperatures when electricity is passed through the cell from one anvil to another.
One known cell configuration, shown in
While the cell configuration shown in
A cell for an HPHT press may comprise a body with a plurality of canisters disposed therein. At least one unique heater element, such as an electrically resistive heater, may be disposed adjacent each of the canisters.
At least one temperature sensor may also be disposed within the body to measure temperature. In various embodiments, there may be at least one temperature sensor for each of the canisters or for each of the unique heater elements.
The at least one heater element may form part of an electrical circuit reaching outside of the body. Such an electrical circuit may have various configurations. In an example configuration, electricity may pass from a first anvil into the cell, through a first heater element adjacent a first canister, through a first electrically conductive tube about a diameter of the first canister, through a center form within the body, through a second electrically conductive tube about a second canister, through a second heater element and to a second anvil.
Heat may be generated within the cell when the anvils are energized. Additionally, a voltage drop over each unique heater element, and thus the amount of heat generated, may be determined from voltages at the anvils. Once determined, the voltage drop over each unique heater element may be regulated by adjusting the voltages at the anvils.
When a cell comprises a plurality of heater elements, additional electrical circuits comprising at least one different heater element and at least one different anvil may be created. Thus, a difference in electrical resistance between unique heater elements may be determined from voltages at the anvils. In some embodiments, it may be desirable to alternate between the various electrical circuits.
Where a center form comprises part of a first electrical circuit with a unique heater element on either side, a second electrical circuit may have at least one of the unique heater elements of the first electrical circuit and at least one different unique heater element.
The generally cubic shaped body 300 comprises six sides 321a, b, c, (only three of which are viewable) each comprising a bore 323a, b, c, therein. Each of the bores 323a, b, c may comprise a respective center axis 329a, b, c passing through a center of the body and be sized to receive an individual canister (not shown). Similarly, the center form 330 may comprise six seats 333a, b, c, each aligned with one of the bores 323a, b, c and sized to receive a canister.
Regardless of the configuration chosen, use of such a balanced cell in an HPHT press has many advantages. For example,
In such a configuration, as anvils of an HPHT press converge and apply pressure to each side of the cell, each of the canisters may receive substantially equal amounts of pressure and from the same relative directions. It is believed that such substantially equal amounts of pressure may result in more uniform end products. Further, as electricity is passed from one anvil to another, it may travel through a first electrically resistive heater, a first metal tube, the center form, and then out a second metal tube and a second electrically resistive heater. Through this electrical path, each of the canisters may receive substantially equal amounts of heat and from the same relative directions. It is believed that such substantially equal amounts of heat may further result in more uniform end products. To more accurately ensure substantially equal amounts of heat, at least one temperature sensor 632, such as a thermocouple or thermistor, may be disposed within the body to measure the temperature. In various embodiments, there may be at least one temperature sensor for each of the canisters 640 or for each of the electrically resistive heaters 607.
For instance,
One of the advantages of forming a balanced cell partially from generally pyramidal shaped forms as described above is the ease of creating a body comprising multiple materials comprising differing properties. For instance,
While forming a cell comprising different material properties on the inside from the outside may be difficult when working with a solid cube, pressing synthetic pyrophyllite may be a straightforward operation for creating a pyramidal shaped form comprising multiple materials as shown in the embodiment of
Another advantage of forming a balanced cell partially from generally pyramidal shaped forms 920a, b is the ability to hold at least portions of the cell together by joining edges of adjacent pyramidal shaped forms 920a, b with dovetails 927 as shown in an embodiment shown in
While we have generally discussed substantially cubic shaped cells up to this point where each of a plurality of sides of the cell are generally planar and disposed at substantially similar angles from adjacent sides, those of skill in the art will recognize that other shapes, such as a tetrahedron and a dodecahedron could be used with the present invention as well. Embodiments of each are shown in
Whereas the present invention has been described in particular relation to the drawings attached hereto, it should be understood that other and further modifications apart from those shown or suggested herein, may be made within the scope and spirit of the present invention.
This patent claims priority to U.S. Provisional Pat. App. No. 62/044,094 entitled “Symmetrical Cell Design” and filed Aug. 29, 2014; U.S. Provisional Pat. App. No. 62/045,752 entitled “Individual Resistance Heating for a High Pressure Cell” and filed Sep. 4, 2014; and U.S. Provisional Pat. App. No. 62/052,191 entitled “Central Conductor Comprising Indentations for HPHT Cell” and filed Sep. 18, 2014; which are incorporated herein by reference for all that they contain. This patent is also a continuation-in-part of U.S. patent application Ser. No. 14/837,761 entitled “Balanced Cell for High-Pressure High-Temperature Press” and filed Aug. 27, 2015.
Number | Name | Date | Kind |
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3328841 | Brayman | Jul 1967 | A |
3829544 | Hall | Aug 1974 | A |
4196181 | Vereschagin | Apr 1980 | A |
6336802 | Hall | Jan 2002 | B1 |
7371280 | Sung | May 2008 | B2 |
8074566 | Bach | Dec 2011 | B1 |
8371212 | Bach | Feb 2013 | B1 |
Entry |
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Wang & He, A hybrid pressure cell of pyrophyllite and magnesium oxide to extend the pressure range for large volume cubic presses, High Pressure Research, Feb. 21, 2012. |
Number | Date | Country | |
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20160059506 A1 | Mar 2016 | US |
Number | Date | Country | |
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62044094 | Aug 2014 | US | |
62045752 | Sep 2014 | US | |
62052191 | Sep 2014 | US |
Number | Date | Country | |
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Parent | 14837761 | Aug 2015 | US |
Child | 14838118 | US |