US3628779A - Furnace for heat-treating objects under high pressure - Google Patents

Furnace for heat-treating objects under high pressure Download PDF

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Publication number
US3628779A
US3628779A US866887A US3628779DA US3628779A US 3628779 A US3628779 A US 3628779A US 866887 A US866887 A US 866887A US 3628779D A US3628779D A US 3628779DA US 3628779 A US3628779 A US 3628779A
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US
United States
Prior art keywords
furnace
high pressure
chamber
pressure
insulating
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Expired - Lifetime
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US866887A
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English (en)
Inventor
Hans Lundstrom
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ABB Norden Holding AB
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ASEA AB
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Filing date
Publication date
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Publication of US3628779A publication Critical patent/US3628779A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B11/00—Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses
    • B30B11/001—Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses using a flexible element, e.g. diaphragm, urged by fluid pressure; Isostatic presses
    • B30B11/002—Isostatic press chambers; Press stands therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/12—Both compacting and sintering
    • B22F3/14—Both compacting and sintering simultaneously
    • B22F3/15—Hot isostatic pressing

Definitions

  • ABSTRACT A vertical furnace includes a press stand and a cylindrical pressure chamber suspended in the press stand.
  • the pressure chamber includes a high-pressure cylinder and end members.
  • the high-pressure cylinder includes a furnace chamber provided with insulation between the pressure cylinder and the walls of the pressure chamber. This insulation is a cylindrical sheath which depends from an end member fixed in one end of the high-pressure cylinder.
  • the end closures include insulating bodies which extend into the furnace member.
  • the present invention relates to cylindrical, preferably vertical furnaces for simultaneous treatment of a material at high temperatures, up to l,500 C. and high pressure, preferably 500 bar and above.
  • the furnaces make possible, for instance, pressure-sintering of powder bodies.
  • pressure-sintering of powder bodies By sintering under high pressure it is possible to achieve greater density than with sintering at atmospheric pressure and thus obtain better properties of the finished product in many respects.
  • the sintering can also be carried out at lower temperatures than is possible at atmospheric pressure and the grain growth can therefore be limited during the sintering.
  • the greater density and more favorable structure of the sintered product makes it stronger body arranged in the pressure chamber, the body consisting of an insulating sheath with insulating lid and bottom.
  • the gas normally used, argon which at the high operating pressure being used has very greatdensity but at the same time low viscosity, only 4-5 times that of air at atmospheric pressure, is thus very mobile.
  • the heat-insulating hollow body is designed so that the least possible convection occurs between the actual furnace chamber and the inner walls of the pressure chamber so that the heat losses can be kept low.
  • a cylindrical sheath has been used for insulation which rests on the lower end closure.
  • the sheath is provided with a detachable lid which is removed before the finished product is withdrawn and replaced after the insertion of a new charge. Due to the pressure difference between the upper part of the furnace chamber and the gap between the insulating sheath and the high pressure cylinder, leakage between lid and insulating sheath causes hot gas to flow from the furnace chamber out into the gap.
  • the heat loss causes increased power demands which may lead to uneven temperature distribution or may make it difficult or impossible to increase the temperature to the desired level.
  • the time for an operating cycle is thus increased. If the worst comes to the words, the charge may even be damaged.
  • the sealing between the lid and sheath of the insulation is thus essential for the function of the furnace, but it has proved difficult to make lid and sheath so that a completely reliable gastight seal is obtained.
  • the present invention relates to a furnace in which convection between the furnace chamber and the gap between the insulating sheath and high pressure cylinder is safely prevented.
  • the invention is particularly suitable for furnaces where the axial pressure operating on the end closures in a pressure chamber is taken up by a separate, surrounding press stand. However, at low pressures threaded end closures may also be used.
  • the invention is essentially characterized in that the insulating cylindrical sheath is suspended on the upper end member.
  • this comprises a fixed ringshaped part on which the insulating cylindrical sheath is suspended and the opening of which forms the charging opening, and a lid projecting into the charging opening, in which lid of the insulation is suitably applied.
  • the ring-shaped part end closure and the insulating sheath are connected to each other in a gastight manner by means of sealings ring.
  • FIG. 1 shows, partly in section, a furnace comprising a stationary high pressure chamber and a movable press stand to take up the axial forces operating on the end closures of the high pressure chamber.
  • FIG. 2 shows on a larger scale and in section, details of the end parts of the high pressure chamber.
  • FIG. 1 designates a press stand which is movable between the position shown in the drawing and a position where the stand surrounds the high pressure chamber 2.
  • the press stand is of the type consisting of yokes 3 and 4, spacers 5 and a strip mantle 6.
  • the stand is carried by wheels 7 running on rails 8.
  • the high pressure chamber 2 is carried by a pillar 9 and contains a high pressure cylinder consisting of an inner tube 10, a surrounding prestressed strip sheath ill and end rings 12 which axially hold together the strip sheath and form the suspension means by which the high pressure chamber is attached to the pillar 9.
  • the chamber 2 has a lower end closure 13 which projects into the tube 10 of the high pressure cylinder.
  • the end closure In the end closure is a groove into which is inserted a sealing ring 14, a channel 15 for the supply of pressure medium and a channel 16 for cables to feed heating elements 17 to heat the furnace.
  • the elements 17 are supported by a cylinder 18 which rests on an insulating bottom 19 which projects into an insulating sheath 20.
  • the upper end closure has an annular part 21 with a sealing ring 22 which seals against the tube 10.
  • the sheath 20 is suspended in the part 21 and connected in a gastight manner to this.
  • the end closure also has a lid 23 to close the opening in part 21 which is usually fixed in the high pressure cylinder.
  • the lid is provided with a sealing ring 24 which seals against the inner surface of the part 21 and with an insulating lid 25 which, when the high pressure chamber is sealed, projects into the cylinder 20 and forms part of the insulating shell surrounding the actual furnace chamber 26.
  • the lid 23 is attached to a bracket 27 supported by an operating rod 28 which can be raised, lowered and turned.
  • FIG. 2 shows on a larger scale part of the high pressure chamber 2 with the end closures projecting into the tube 10 of the high pressure cylinder.
  • the insulating sheath 20 is conventionally constructed of a number of metal tubes 29, 30 and 31 with intermediate layers 32 and 33 of insulating material and a connecting ring 34.
  • the insulating lid 25 has been scaled to the ring 34 after each charge has been inserted. This is time consuming and since the seal could not be effectively cooled it required great care in applying the seal. If, due to temperature fluctuations, cracks were formed between the lid and the ring 34, hot pressure medium flowed out radially past the insulatingv sheath between the ring 34 and the end closure and was cooled upon contact with the wall of the tube 10.
  • the lid 25 includes a sheet metal dome 37 filled with insulating material and connected to the lid 23 by a flange 38.
  • Vertical furnace for simultaneously treating material at high temperatures and in a gas atmosphere of high pressure, comprising a press stand, a cylindrical pressure chamber suspended in said press stand and comprising a high pressure cylinder and end members for closing gastightly the pressure cylinder which are held in place by said press stand and take up the axial forces which a pressure medium in the pressure chamber exerts on the end members, a furnace chamber within the high pressure cylinder, means to supply high pressure fluid to the furnace chamber, insulation arranged between said furnace chamber and the walls of the pressure chamber, which insulation comprises a cylindrical sheath of insulating material and an insulating lid and bottom, in which the insulating cylindrical sheath is suspended from the upper end member.
  • the upper end member comprises a fixedly attached ring-shaped part from which the insulating cylindrical sheath is suspended and the opening of which forms the charging opening and a removable lid having a part projecting into the charging opening.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Powder Metallurgy (AREA)
  • Furnace Details (AREA)
  • Heat Treatment Of Strip Materials And Filament Materials (AREA)
US866887A 1968-10-24 1969-10-16 Furnace for heat-treating objects under high pressure Expired - Lifetime US3628779A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE14367/68A SE326942B (xx) 1968-10-24 1968-10-24

Publications (1)

Publication Number Publication Date
US3628779A true US3628779A (en) 1971-12-21

Family

ID=20298976

Family Applications (1)

Application Number Title Priority Date Filing Date
US866887A Expired - Lifetime US3628779A (en) 1968-10-24 1969-10-16 Furnace for heat-treating objects under high pressure

Country Status (8)

Country Link
US (1) US3628779A (xx)
AT (1) AT293031B (xx)
DE (1) DE1953306C3 (xx)
FR (1) FR2021439A1 (xx)
GB (1) GB1286517A (xx)
IE (1) IE33400B1 (xx)
SE (1) SE326942B (xx)
SU (1) SU402185A3 (xx)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3695597A (en) * 1968-10-24 1972-10-03 Asea Ab Furnace for heat treating objects under pressure
US4022446A (en) * 1975-10-23 1977-05-10 Autoclave Engineers, Inc. Quenching in hot gas isostatic pressure furnace
US4602769A (en) * 1984-05-11 1986-07-29 National Forge Company Apparatus for the cooling of articles which have been subjected to an isostatic pressing process
US5354519A (en) * 1992-03-18 1994-10-11 Schweizerische Eidgenossenschaft Vertreten Durch Die Eidg. Munitionsfabrik Thun Der Gruppe Fur Ruestungsdienste Method and apparatus for the quasi-isostatic pressure-forming of thermoplastically-bonded precision explosive charges
US10625446B2 (en) * 2016-11-09 2020-04-21 National Formosa University High-temperature hot-pressing molding machine

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2328020C3 (de) * 1972-06-13 1981-05-07 ASEA AB, Västerås Isoliermantel für den in einer Druckkammer angeordneten Ofenraum einer vertikalen Rohrofenanlage zum isostatischen Heißpressen
RU2166409C1 (ru) 2000-11-08 2001-05-10 Губенко Лев Анатольевич Силовой модуль автоклава
DE10116104A1 (de) † 2001-03-30 2002-10-10 Sig Combibloc Sys Gmbh Verfahren und Vorrichtung zur kontinuierlichen Abfüllung einer vorgegebenen Menge eines Produktes in Packungen

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1371299A (en) * 1920-02-02 1921-03-15 Air Liquide Apparatus for effecting exothermic chemical syntheses at high temperature and pressure
US1498519A (en) * 1924-06-17 Poration
US1500789A (en) * 1920-06-17 1924-07-08 Aoyagi Eiji Electrometallurgical process for manufacture of ductile bodies of high-fusing metals and alloys of same
US1884748A (en) * 1930-12-24 1932-10-25 Hevi Duty Electric Co Heat treatment system
US2341860A (en) * 1942-02-09 1944-02-15 Sk Wellman Co Method of making chambered metallic articles
US2434237A (en) * 1943-09-13 1948-01-06 Sk Wellman Co Apparatus for applying powdered metal briquets to curved metallic surfaces
US3198503A (en) * 1963-04-29 1965-08-03 Basic Products Corp Furnace
US3419935A (en) * 1966-12-19 1969-01-07 Atomic Energy Commission Usa Hot-isostatic-pressing apparatus

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1498519A (en) * 1924-06-17 Poration
US1371299A (en) * 1920-02-02 1921-03-15 Air Liquide Apparatus for effecting exothermic chemical syntheses at high temperature and pressure
US1500789A (en) * 1920-06-17 1924-07-08 Aoyagi Eiji Electrometallurgical process for manufacture of ductile bodies of high-fusing metals and alloys of same
US1884748A (en) * 1930-12-24 1932-10-25 Hevi Duty Electric Co Heat treatment system
US2341860A (en) * 1942-02-09 1944-02-15 Sk Wellman Co Method of making chambered metallic articles
US2434237A (en) * 1943-09-13 1948-01-06 Sk Wellman Co Apparatus for applying powdered metal briquets to curved metallic surfaces
US3198503A (en) * 1963-04-29 1965-08-03 Basic Products Corp Furnace
US3419935A (en) * 1966-12-19 1969-01-07 Atomic Energy Commission Usa Hot-isostatic-pressing apparatus

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3695597A (en) * 1968-10-24 1972-10-03 Asea Ab Furnace for heat treating objects under pressure
US4022446A (en) * 1975-10-23 1977-05-10 Autoclave Engineers, Inc. Quenching in hot gas isostatic pressure furnace
US4602769A (en) * 1984-05-11 1986-07-29 National Forge Company Apparatus for the cooling of articles which have been subjected to an isostatic pressing process
US5354519A (en) * 1992-03-18 1994-10-11 Schweizerische Eidgenossenschaft Vertreten Durch Die Eidg. Munitionsfabrik Thun Der Gruppe Fur Ruestungsdienste Method and apparatus for the quasi-isostatic pressure-forming of thermoplastically-bonded precision explosive charges
US10625446B2 (en) * 2016-11-09 2020-04-21 National Formosa University High-temperature hot-pressing molding machine

Also Published As

Publication number Publication date
AT293031B (de) 1971-09-27
DE1953306A1 (de) 1970-10-29
FR2021439A1 (xx) 1970-07-24
IE33400L (en) 1970-04-24
DE1953306C3 (de) 1979-08-23
DE1953306B2 (de) 1972-02-17
SE326942B (xx) 1970-08-10
SU402185A3 (xx) 1973-10-12
IE33400B1 (en) 1974-06-12
GB1286517A (en) 1972-08-23

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