US3786164A - Vacuum oven for firing ceramic facings - Google Patents

Vacuum oven for firing ceramic facings Download PDF

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Publication number
US3786164A
US3786164A US00246641A US3786164DA US3786164A US 3786164 A US3786164 A US 3786164A US 00246641 A US00246641 A US 00246641A US 3786164D A US3786164D A US 3786164DA US 3786164 A US3786164 A US 3786164A
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United States
Prior art keywords
inert gas
firing
oven
conduit
zone
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Expired - Lifetime
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US00246641A
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English (en)
Inventor
K Hintenberger
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Individual
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Individual
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Publication date
Priority claimed from DE19712119563 external-priority patent/DE2119563C/de
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Publication of US3786164A publication Critical patent/US3786164A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J6/00—Heat treatments such as Calcining; Fusing ; Pyrolysis
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
    • A61C13/00—Dental prostheses; Making same
    • A61C13/20—Methods or devices for soldering, casting, moulding or melting
    • 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
    • F27D11/00—Arrangement of elements for electric heating in or on furnaces
    • F27D11/02—Ohmic resistance heating

Definitions

  • ABSTRACT Ceramic facings are filed in a refractory lined oven Primary Examiner-Volodymyr Y. Mayewsky Attorney-Kurt Kelman' having a pre-heating zone and a firing zone, the facings being charged into the pre-heating zone on a caroven c plied with inert gas from a supply the purpose and the valves in the branch conduits may be selectivel ated.
  • a venting valve is mounted in the upper United States Patent [191 Hintenberger 1 VACUUM OVEN FOR FIRING CERAMIC FACINGS [76] Inventor: Karl Hintenberger, Krogerstr. 4,
  • the invention concerns an oven for firing ceramic facings mounted on metal supports made of alloys conalready been suggested, for example, chromium cobalt alloys, which are more closely related to the ceramic paste than known noble metal firing alloys because of, among other things, their heat transfer properties.
  • alloys conalready been suggested, for example, chromium cobalt alloys, which are more closely related to the ceramic paste than known noble metal firing alloys because of, among other things, their heat transfer properties.
  • chromium cobalt alloys are more closely related to the ceramic paste than known noble metal firing alloys because of, among other things, their heat transfer properties.
  • the purpose of the present invention is to provide a firing oven which ensures that such finishing treatment can be completely, i.e. to a large extent, dispensed with, or that oxidation of such alloys cannot occur during firing.
  • This purpose is accomplished according to the invention, with an oven comprising a housing defining a vacuum-tight inner chamber having a pre-heating zone and a firing zone.
  • a carriage is mounted in the inner chamber and is movable between the pie-heating zone and the firing zone.
  • a venting valve is mounted in the upper part of the housing and' is operable between a closed and a venting position
  • a main conduit is connected to the lower part of the housing and opens into the inner chamber, branch conduits connecting the intake of a vacuum pump and a supply of inert gas to the main conduit.
  • Valve means is selectively operable to connect the vacuum pump or the inert gas supply to the main conduit.
  • FIG. 1 the oven, in section, and the vacuum branch and inert gas feed lines;
  • FIG. 2 a portion of a modified feed line with an additional pressure pump incorporated and FIG. 3 a section through a part of the denture to be fired.
  • the firing oven is shown to have a housing 1, defining a vacuum-tight inner chamber 2 having a pre-heating zone 2 and a firing zone proper 2".
  • the pre-heating zone is lined by a conventional refractory lining 2a and the firing zone is lined by a conventional refractory lining 2b.
  • Resistance heaters 22 of known design are mounted in the refractory lining wall 2b of firing zone.
  • An end wall 20 of refractory material closes off the firing zone 2".
  • the inner chamber 2 of the oven housing may be vented by venting valve 3 mounted in the upper part of housing 1 and operable between a closedand a venting position.
  • a main conduit 4 is' connected to connector 4 in the lower part of the housing and opens into the inner chamber 2 of the oven.
  • Branch conduits 7a and 7 connect the intake of vacuum pump 6 and a supply container 9 of inert gas, respectively, to main conduit 4.
  • a charging duct 14 extends'transversely through the refractory lining 2a and opens into pre-heating zone 2 to enable the object to be fired to be charged into the oven, the duct being closable vacuum-tight by a door.
  • the oven is charged through duct 14, the object is placed on carriage 15 which is mounted in the inner chamber 2 and is movable between the pre-heating zone 2' and the firing zone 2".
  • Evacuation of the inner chamber of the oven is effected with the valve 5 in branch conduit 70 open and the valve 8 in branch conduit 7 closed through the vacuum pump 6, while valve 3 is also closed. This valve is only opened in the case of initial charging or flooding of the inner chamber of the oven with inert gas.
  • a filter in series with the vacuum pump 6 is shown at 16 whilst 10 indicates in broken lines a receiver for the withdrawn inert gas which can be provided if necessary and from which a further branch conduit 11 with nonreturn valve 12 leads to a section of branch conduit 7 which connects valve 8 with the inert gas container 9.
  • FIG. 3 shows a section through a part of a preferred dental prosthesis for the oven of this invention where, in the top of the metal support element 20 which carries the paste to be fired 21, there is provided a small hole 18 to improve venting of the cavity 19 in the support 20.
  • the oven is operated as follows:
  • vent-' When the firing oven is put into operation, the vent-' to flood the inner chamber of the oven with inert gas while it is being vented. After flooding the inner chamher 2 with inert gas, venting valve 3 and valve 8 are 3 Since the inner chamber of the oven is now filled with inert gas, venting may be dispensed with in the next firing cycle. Loss of inert gas is reduced to a minimum by provision of inert gas receiver receiving evacuated inert gas from vacuum pump 6, the inert gas being fed back into branch conduit 7-through further branch conduit 11 and back-flow of the inert gas being prevented by check valve 12 in conduit 11.
  • valves 5 and 8 are solenoid valves which may be connected in an electric control circuit also containing the time and temperature regulators for heaters What is claimed is:
  • An oven for firing ceramic facings mounted on metal supports of an oxidizable alloy containing no noble metals comprising a. a housing lined with electrically and thermally insulating refractory linings defining a vacuum tight inner chamber having a pre-heating zone and a firing zone,
  • a charging duct in the refractory lining of the preheating zone and leading thereinto the housing having a door for vacuum-tightly closing the charging duct
  • venting valve mounted in the upper part of the housing and operable between a closed and a venting position
  • a vacuum pump having an intake and an output
  • branch conduits connecting the intake of the vacuum pump and the inert gas supply respectively to the main conduit
  • valve means in the branch conduits selectively operable to open the vacuum pump intake or the inert gas supply to the main conduit for evacuating the inner chamber or to feed inert gas thereto.
  • the firing oven of claim 1 comprising a pressure pump mounted in the branch conduit connecting the inert gas supply to the main conduit.
  • the firing oven of claim 1 further comprising a receiver for the inert gas, the output of the vacuum pump being connected to the inert gas receiver, a further branch conduit connected between the inert gas receiver and the branch conduit connecting the inert gas supply to the conduit, the further branch conduit opening into the latter branch conduit upstream of the valve means, and a check valve arranged in the further conduit.

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  • Health & Medical Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Veterinary Medicine (AREA)
  • Thermal Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Epidemiology (AREA)
  • Physics & Mathematics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Dentistry (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Oral & Maxillofacial Surgery (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Furnace Details (AREA)
  • Dental Prosthetics (AREA)
US00246641A 1971-04-22 1972-04-24 Vacuum oven for firing ceramic facings Expired - Lifetime US3786164A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19712119563 DE2119563C (de) 1971-04-22 Verfahren zum Betreiben eines Ofens zum Brennen dentalkeramischer Verblendun gen und Brennofen zu seiner Durchführung

Publications (1)

Publication Number Publication Date
US3786164A true US3786164A (en) 1974-01-15

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Family Applications (1)

Application Number Title Priority Date Filing Date
US00246641A Expired - Lifetime US3786164A (en) 1971-04-22 1972-04-24 Vacuum oven for firing ceramic facings

Country Status (4)

Country Link
US (1) US3786164A (de)
AT (1) AT349615B (de)
DE (1) DE2119563B1 (de)
GB (1) GB1389295A (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4445024A (en) * 1981-03-24 1984-04-24 Research Technology Canberra Pty. Ltd. Electric kiln
US20130029279A1 (en) * 2011-07-25 2013-01-31 Ivoclar Vivadent Ag Dental Oven

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4137334A1 (de) * 1991-11-13 1993-05-19 Alfons Schmidseder Verfahren und vorrichtung zum formpressen von dentalkeramik
DE4302570C1 (de) * 1993-01-29 1994-03-24 Otto Kozmacs Brennofen für das Brennen von Dental-Keramik

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4445024A (en) * 1981-03-24 1984-04-24 Research Technology Canberra Pty. Ltd. Electric kiln
US20130029279A1 (en) * 2011-07-25 2013-01-31 Ivoclar Vivadent Ag Dental Oven
US9951993B2 (en) * 2011-07-25 2018-04-24 Ivoclar Vivadent Ag Dental oven

Also Published As

Publication number Publication date
ATA345372A (de) 1978-09-15
AT349615B (de) 1979-04-10
GB1389295A (en) 1975-04-03
DE2119563B1 (de) 1972-10-12

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