EP0329378B1 - Vacuum heat treating furnace - Google Patents

Vacuum heat treating furnace Download PDF

Info

Publication number
EP0329378B1
EP0329378B1 EP19890301381 EP89301381A EP0329378B1 EP 0329378 B1 EP0329378 B1 EP 0329378B1 EP 19890301381 EP19890301381 EP 19890301381 EP 89301381 A EP89301381 A EP 89301381A EP 0329378 B1 EP0329378 B1 EP 0329378B1
Authority
EP
European Patent Office
Prior art keywords
vacuum chamber
vacuum
heat treating
treating furnace
heat
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP19890301381
Other languages
German (de)
French (fr)
Other versions
EP0329378A3 (en
EP0329378A2 (en
Inventor
Hajime Ishimaru
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Japan Science and Technology Agency
Original Assignee
Research Development Corp of Japan
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Research Development Corp of Japan filed Critical Research Development Corp of Japan
Publication of EP0329378A2 publication Critical patent/EP0329378A2/en
Publication of EP0329378A3 publication Critical patent/EP0329378A3/en
Application granted granted Critical
Publication of EP0329378B1 publication Critical patent/EP0329378B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D1/00—Casings; Linings; Walls; Roofs
    • F27D1/0003—Linings or walls
    • F27D1/0006—Linings or walls formed from bricks or layers with a particular composition or specific characteristics
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B5/00—Muffle furnaces; Retort furnaces; Other furnaces in which the charge is held completely isolated
    • F27B5/04—Muffle furnaces; Retort furnaces; Other furnaces in which the charge is held completely isolated adapted for treating the charge in vacuum or special atmosphere
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D1/00—Casings; Linings; Walls; Roofs
    • F27D1/12—Casings; Linings; Walls; Roofs incorporating cooling arrangements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D9/00—Cooling of furnaces or of charges therein
    • F27D2009/0002—Cooling of furnaces
    • F27D2009/0018—Cooling of furnaces the cooling medium passing through a pattern of tubes
    • F27D2009/0021—Cooling of furnaces the cooling medium passing through a pattern of tubes with the parallel tube parts close to each other, e.g. a serpentine

Definitions

  • the present invention relates to a vacuum heat treating furnace, more specifically to a vacuum heat treating furnace capable of being highly stable against heat treatments, including baking treatment to be applied on the component parts of particle accelerators and conducting said heat treatment at high efficiency.
  • vacuum heat treating furnaces in which a thermal shield enclosure and a heater designed to heat the inner space of said enclosure is provided in a vacuum chamber, have been known.
  • the vacuum chamber is normally composed of steel materials with high melting points, including common steel and stainless steel.
  • These steel materials possess high heat radiation rate and low thermal conductivity, and hence sufficient space is provided between the vacuum chamber and the thermal shield enclosure disposed therein so that these steel materials can withstand the heat transferred from the hot heat treating portion.
  • a cooling piping is also provided to cool the wall of the vacuum chamber.
  • the invention provides a vacuum heat treating furnace having a thermal shield enclosure defining an inner heat treatment region, supported by an insulating supporting element and located inside a vacuum chamber having a connection for a vacuum exhaust system, so that said inner heat treatment region is spaced from the vacuum chamber wall, an electric heater for heating said heat treatment region and an electric power supply connection to said electric heater, characterised in that said vacuum chamber is formed of aluminium or of an aluminium alloy and the inner wall surface of said vacuum chamber is provided with a smooth finish.
  • the invention may provide a vacuum heat treating furnace which overcomes the defects of the conventional devices in terms of size and cost, and is capable of achieving the downsizing of the vacuum chamber and the elimination or simplification of the cooling system through improvement of the material of the vacuum chamber.
  • the furnace is highly stable against heat treatments, including baking treatment, and can conduct said heat treatment as high efficiency.
  • Fig. 1 is a vertical sectional view of one of the embodiments of the vacuum heat treating furnace according to the present invention.
  • a thermal shield enclosure 4 supported by an adiabatic supporting element 3 made of ceramic or other material is provided within a vacuum chamber 2 having a connection portion 1 to a vacuum exhaust system.
  • the external surface of this thermal shield enclosure 4 is isolated from the inner wall surface 2a of the vacuum chamber 2 via space 5.
  • a heat treatment region 6 is provided, and an electric heater 7 composed of tungsten wire, nichrome wire or the like and designed to heat this heat treatment region 6 is embedded in the wall of the thermal shield enclosure 4. This heater 7 is linked to an electric power supply system 8.
  • the vacuum chamber 2 is formed of aluminium metal material (aluminium or aluminium alloy whose main ingredient is aluminium), and the inner wall surface of said vacuum chamber 2 is smoothly finished. It is preferable to provide the inner wall surface of the vacuum chamber 2 with a specular finish.
  • the melting point is about 600°C, lower than that of about 1200°C of the steel material which has been employed for the vacuum chamber in the conventional heat treating furnaces.
  • the heat radiation rate on the surface area of aluminium metal material is in the order of 0.04, and said aluminium metal material offers markedly less heat absorption than the conventional vacuum chamber materials, such as soft steel (a radiation rate of 0.5) and stainless steel (a radiation rate of 0.4).
  • thermal conductivity As for thermal conductivity also, while the conventional soft steel is 167 kJ/mh°C (40 kcal/mh°C) and stainless steel 63 kJ/mh°C (15 kcal/mh°C), the aluminium material according to the preferred embodiment is 711 kJ/mh°C (170kcal/mh°C), which indicates that the latter provides improved release of the heat absorbed.
  • the lower melting point of the aluminium metal material does not adversely affect the thermal resistance strength vacuum chamber 2. Accordingly, the flow rate of the cooling water used in the cooling system comprised of a cooling water piping 9 designed to cool the vacuum chamber 2 can be reduced, and the capacity of the cooling water pump (not shown) can also be made smaller, thereby permitting the simplification of the cooling system.
  • cooling water piping may be provided to cool the high temperature area comprising of heat treatment region 6 and thermal shield enclosure 4.
  • cooling absorbing equipment may be provided in vacuum chamber in order to absorb pollution materials generated from the high temperature area, which impede thermal efficiency of the vacuum heat treating furnace.
  • the vacuum heat treating furnace according to the present invention has been accomplished by adopting aluminium metal material for the vacuum chamber, having low heat radiation and high thermal conductivity, although said material has been conventionally thought unsuitable for material of a vacuum heat treating furnace because of its lower melting point.
  • a combination of the thermal characteristics of aluminium metal material, whose heat radiation is 1-digit lower than the conventional steel materials and whose thermal conductivity is markedly higher, and smoothly finished inner wall surface of the vacuum chamber can improve the heat resistance of the vacuum chamber and make the space between the vacuum chamber and the thermal shield enclosure inside said chamber to be less than the conventional types. This could reduce the size and weight of the vacuum chamber or widen the heat treatment region within the thermal shield enclosure wall. Since the quantity of heat transferred from the thermal shield enclosure to the vacuum chamber becomes less, it becomes possible to substantially simplify or eliminate the cooling system which is used to cool the vacuum chamber. Furthermore, the improved thermal efficiency of the vacuum heat treating furnace can help to save the power applied on an electric heater.

Description

  • The present invention relates to a vacuum heat treating furnace, more specifically to a vacuum heat treating furnace capable of being highly stable against heat treatments, including baking treatment to be applied on the component parts of particle accelerators and conducting said heat treatment at high efficiency.
  • Conventionally vacuum heat treating furnaces, in which a thermal shield enclosure and a heater designed to heat the inner space of said enclosure is provided in a vacuum chamber, have been known. In such conventional vacuum heat treating furnaces, the vacuum chamber is normally composed of steel materials with high melting points, including common steel and stainless steel.
  • These steel materials possess high heat radiation rate and low thermal conductivity, and hence sufficient space is provided between the vacuum chamber and the thermal shield enclosure disposed therein so that these steel materials can withstand the heat transferred from the hot heat treating portion. A cooling piping is also provided to cool the wall of the vacuum chamber.
  • For the aforementioned reasons, in the conventional vacuum heat treating furnaces, the vacuum chamber attained larger size, and a large amount of cooling water had to be introduced into the cooling piping; it inevitably became costly.
  • Viewed from one aspect the invention provides a vacuum heat treating furnace having a thermal shield enclosure defining an inner heat treatment region, supported by an insulating supporting element and located inside a vacuum chamber having a connection for a vacuum exhaust system, so that said inner heat treatment region is spaced from the vacuum chamber wall, an electric heater for heating said heat treatment region and an electric power supply connection to said electric heater, characterised in that said vacuum chamber is formed of aluminium or of an aluminium alloy and the inner wall surface of said vacuum chamber is provided with a smooth finish.
  • At least in preferred embodiments, the invention may provide a vacuum heat treating furnace which overcomes the defects of the conventional devices in terms of size and cost, and is capable of achieving the downsizing of the vacuum chamber and the elimination or simplification of the cooling system through improvement of the material of the vacuum chamber. The furnace is highly stable against heat treatments, including baking treatment, and can conduct said heat treatment as high efficiency.
  • An embodiment of the invention will now be described, by way of example only, with reference to the drawings, in which:
    • Fig. 1 is a vertical sectional view of one of the embodiments of a vacuum heat treating furnace according to the present invention:
    • Figs. 2 and 3 are partially sectional views of the transformed version of the cooling system of the vacuum heat treating furnace as illustrated in Fig. 1
       Referring now in detail to the drawings, the embodiments of the present invention will be shown, and detailed descriptions given to this invention.
  • Fig. 1 is a vertical sectional view of one of the embodiments of the vacuum heat treating furnace according to the present invention.
  • In this example, a thermal shield enclosure 4 supported by an adiabatic supporting element 3 made of ceramic or other material is provided within a vacuum chamber 2 having a connection portion 1 to a vacuum exhaust system. The external surface of this thermal shield enclosure 4 is isolated from the inner wall surface 2a of the vacuum chamber 2 via space 5.
  • Inside the thermal shield enclosure 4 a heat treatment region 6 is provided, and an electric heater 7 composed of tungsten wire, nichrome wire or the like and designed to heat this heat treatment region 6 is embedded in the wall of the thermal shield enclosure 4. This heater 7 is linked to an electric power supply system 8.
  • In the vacuum heat treating furnace according to the preferred embodiment, the vacuum chamber 2 is formed of aluminium metal material (aluminium or aluminium alloy whose main ingredient is aluminium), and the inner wall surface of said vacuum chamber 2 is smoothly finished. It is preferable to provide the inner wall surface of the vacuum chamber 2 with a specular finish.
  • Pertaining to the aluminium metal material as described above, the melting point is about 600°C, lower than that of about 1200°C of the steel material which has been employed for the vacuum chamber in the conventional heat treating furnaces. However, the heat radiation rate on the surface area of aluminium metal material is in the order of 0.04, and said aluminium metal material offers markedly less heat absorption than the conventional vacuum chamber materials, such as soft steel (a radiation rate of 0.5) and stainless steel (a radiation rate of 0.4). As for thermal conductivity also, while the conventional soft steel is 167 kJ/mh°C (40 kcal/mh°C) and stainless steel 63 kJ/mh°C (15 kcal/mh°C), the aluminium material according to the preferred embodiment is 711 kJ/mh°C (170kcal/mh°C), which indicates that the latter provides improved release of the heat absorbed.
  • In the vacuum chamber 2 made of such aluminium metal material, smooth finish of the inner wall surface helps to reduce the quantity of heat transferred from the thermal shield enclosure 4 through space 5 to the vacuum chamber 2 resulting from heater 7. The heat transferred onto the inner wall surface 2a of the vacuum chamber 2 quickly shifts in the thickness direction of the wall of the vacuum chamber 2 due to the high thermal conductivity of the aluminium metal material, and can be released from the external surface of the vacuum chamber 2.
  • The lower melting point of the aluminium metal material does not adversely affect the thermal resistance strength vacuum chamber 2. Accordingly, the flow rate of the cooling water used in the cooling system comprised of a cooling water piping 9 designed to cool the vacuum chamber 2 can be reduced, and the capacity of the cooling water pump (not shown) can also be made smaller, thereby permitting the simplification of the cooling system.
  • As illustrated in Fig. 2, since it is also possible to make the cooling water piping 9 smaller, it is possible to embed said cooling water piping 9 in the wall of the vacuum chamber 2.
  • Furthermore, as indicated in Fig. 3. sufficient cooling effect can be obtained by merely providing radiating fins 10 on the external wall surface of the vacuum chamber 2.
  • Additionally, cooling water piping may be provided to cool the high temperature area comprising of heat treatment region 6 and thermal shield enclosure 4. Furthermore, cooling absorbing equipment may be provided in vacuum chamber in order to absorb pollution materials generated from the high temperature area, which impede thermal efficiency of the vacuum heat treating furnace.
  • The vacuum heat treating furnace according to the present invention has been accomplished by adopting aluminium metal material for the vacuum chamber, having low heat radiation and high thermal conductivity, although said material has been conventionally thought unsuitable for material of a vacuum heat treating furnace because of its lower melting point.
  • In the vacuum heat treating furnace according to the preferred embodiment, a combination of the thermal characteristics of aluminium metal material, whose heat radiation is 1-digit lower than the conventional steel materials and whose thermal conductivity is markedly higher, and smoothly finished inner wall surface of the vacuum chamber can improve the heat resistance of the vacuum chamber and make the space between the vacuum chamber and the thermal shield enclosure inside said chamber to be less than the conventional types. This could reduce the size and weight of the vacuum chamber or widen the heat treatment region within the thermal shield enclosure wall. Since the quantity of heat transferred from the thermal shield enclosure to the vacuum chamber becomes less, it becomes possible to substantially simplify or eliminate the cooling system which is used to cool the vacuum chamber. Furthermore, the improved thermal efficiency of the vacuum heat treating furnace can help to save the power applied on an electric heater.

Claims (3)

  1. A vacuum heat treating furnace having a thermal shield enclosure defining an inner heat treatment region, supported by an insulating supporting element and located inside a vacuum chamber having a connection for a vacuum exhaust system, so that said inner heat treatment region is spaced from the vacuum chamber wall, an electric heater for heating said heat treatment region, and an electric power supply connection to said electric heater, characterised in that said vacuum chamber is formed of aluminium or of an aluminium alloy and the inner wall surface of said vacuum chamber is provided with a smooth finish.
  2. A vacuum heat treating furnace as claimed in claim 1 wherein cooling means in the form of cooling liquid conduits or fins are associated with the vacuum chamber.
  3. A vacuum heat treating furnace as claimed in claim 2 wherein cooling liquid conduits are embedded in the wall of the chamber.
EP19890301381 1988-02-15 1989-02-14 Vacuum heat treating furnace Expired - Lifetime EP0329378B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP63032046A JP2777798B2 (en) 1988-02-15 1988-02-15 Vacuum heat treatment furnace
JP32046/88 1988-02-15

Publications (3)

Publication Number Publication Date
EP0329378A2 EP0329378A2 (en) 1989-08-23
EP0329378A3 EP0329378A3 (en) 1990-10-03
EP0329378B1 true EP0329378B1 (en) 1993-06-16

Family

ID=12347921

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19890301381 Expired - Lifetime EP0329378B1 (en) 1988-02-15 1989-02-14 Vacuum heat treating furnace

Country Status (3)

Country Link
EP (1) EP0329378B1 (en)
JP (1) JP2777798B2 (en)
DE (1) DE68907072T2 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103673591A (en) * 2013-12-10 2014-03-26 北京神雾环境能源科技集团股份有限公司 Evaporated cooling system of heat accumulating type rod and wire stepping furnace
CN105486093A (en) * 2015-10-13 2016-04-13 常州市武进顶峰铜业有限公司 Casting copper water jacket

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102788496A (en) * 2011-05-16 2012-11-21 钱佼佼 Water-cooling vacuum furnace
JP6575112B2 (en) * 2015-04-02 2019-09-18 富士電機機器制御株式会社 Heat treatment equipment
JP6500873B2 (en) * 2016-10-21 2019-04-17 トヨタ自動車株式会社 Vacuum insulation structure

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1693378A (en) * 1924-12-03 1928-11-27 Westinghouse Electric & Mfg Co Air-cooled furnace wall
FR1496743A (en) * 1966-04-19 1967-10-06 Device for increasing the thermal efficiency of heating chambers
US4030712A (en) * 1975-02-05 1977-06-21 Alco Standard Corporation Method and apparatus for circulating a heat treating gas
GB8613841D0 (en) * 1986-06-06 1986-07-09 Encomech Eng Services Ltd Heat insulating panels
DE3621996A1 (en) * 1986-07-01 1988-01-14 Pfeiffer Vakuumtechnik PLANT FOR HEAT TREATING MATERIALS IN VACUUM AND UNDER PRESSURE

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103673591A (en) * 2013-12-10 2014-03-26 北京神雾环境能源科技集团股份有限公司 Evaporated cooling system of heat accumulating type rod and wire stepping furnace
CN103673591B (en) * 2013-12-10 2015-07-01 北京神雾环境能源科技集团股份有限公司 Evaporated cooling system of heat accumulating type rod and wire stepping furnace
CN105486093A (en) * 2015-10-13 2016-04-13 常州市武进顶峰铜业有限公司 Casting copper water jacket

Also Published As

Publication number Publication date
DE68907072T2 (en) 1993-09-30
EP0329378A3 (en) 1990-10-03
JP2777798B2 (en) 1998-07-23
JPH01208414A (en) 1989-08-22
DE68907072D1 (en) 1993-07-22
EP0329378A2 (en) 1989-08-23

Similar Documents

Publication Publication Date Title
KR101456892B1 (en) Method and apparatus for providing temperature control to a cryopump
JPS60194237A (en) Heater for electric heating radiating heating section
RU96118488A (en) INNER REFRACTORY COOLER
EP0329378B1 (en) Vacuum heat treating furnace
JPS5849435A (en) Light irradiating device
US4508961A (en) Electric radiant heater units for glass ceramic top cookers
US2565722A (en) Cooling device
US4247736A (en) Induction heater having a cryoresistive induction coil
GB1578058A (en) Refractory articles
JPH0752071B2 (en) Vacuum heat treatment furnace
JP3033047B2 (en) Fluid temperature controller
US4463797A (en) Inhibiting shrinkage pipe formation of metal casting
JPH0820868A (en) Vacuum soaking heater
JPS5561049A (en) Radiator for semiconductor
CN108292533A (en) The passive cooling of fission reactor
BRPI0620872A2 (en) magnetic flux transparent thermal insulation screen and heat treatment installation
US3645326A (en) Device for heating and cooling an enclosed chamber
JPS5869362A (en) Solar heat collector
JPS5869361A (en) Solar heat collector
JPH06168899A (en) Heater unit for heating substrate
JPS5831229A (en) Table-top gas heater
JPH0476994A (en) Cooling structure for electronic device
JPH05223340A (en) Water boiler
KR101729278B1 (en) Energy saving heater
KR920002268Y1 (en) Hot-air heater

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): DE FR GB IT

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Kind code of ref document: A3

Designated state(s): DE FR GB IT

17P Request for examination filed

Effective date: 19901122

17Q First examination report despatched

Effective date: 19921016

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE FR GB IT

REF Corresponds to:

Ref document number: 68907072

Country of ref document: DE

Date of ref document: 19930722

ET Fr: translation filed
ITF It: translation for a ep patent filed

Owner name: SOCIETA' ITALIANA BREVETTI S.P.A.

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
REG Reference to a national code

Ref country code: GB

Ref legal event code: IF02

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: IT

Payment date: 20060228

Year of fee payment: 18

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20070216

Year of fee payment: 19

Ref country code: GB

Payment date: 20070216

Year of fee payment: 19

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20070212

Year of fee payment: 19

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20080214

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

Effective date: 20081031

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20080902

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20080229

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20080214

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20070214