EP0344245A1 - Electric immersion heater - Google Patents
Electric immersion heaterInfo
- Publication number
- EP0344245A1 EP0344245A1 EP88909549A EP88909549A EP0344245A1 EP 0344245 A1 EP0344245 A1 EP 0344245A1 EP 88909549 A EP88909549 A EP 88909549A EP 88909549 A EP88909549 A EP 88909549A EP 0344245 A1 EP0344245 A1 EP 0344245A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- sheath
- heating element
- graphite
- gas
- heating
- 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.)
- Granted
Links
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B3/00—Ohmic-resistance heating
- H05B3/62—Heating elements specially adapted for furnaces
- H05B3/64—Heating elements specially adapted for furnaces using ribbon, rod, or wire heater
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B3/00—Ohmic-resistance heating
- H05B3/40—Heating elements having the shape of rods or tubes
- H05B3/42—Heating elements having the shape of rods or tubes non-flexible
Definitions
- the invention relates to devices for electrically heating a resistance medium, devices also commonly known as immersion heaters, of the type comprising an elongated graphite heating element, substantially cylindrical and having two end portions, surrounded by a sheath of refractory material delimiting around the heating element a sealed chamber for retaining a gas capable of protecting the graphite from oxidation.
- Electric heating devices of the type defined above are already known.
- the applicant describes a device comprising a graphite heating element protected against oxidation by an atmosphere containing carbon monoxide formed from the heating element during the first implementation of the device and surrounded by a tubular sheath of refractory ceramic resistant to corrosion. This solution solves many problems.
- the invention aims to provide an electric heating device which responds better than those previously known to the requirements of practice, in particular in that it makes it possible to obtain a form of sheath which is particularly conducive to the diffusion of heat.
- radiant from the graphite heating element which was impossible with ceramic sheaths whose shape was limited to the cylinder of revolution or the oval, in that it eliminates the risk of electric short circuit between the graphite heating element and the sheath, risks caused by the movement and vibrations of the device in its heated medium, in that it comprises means for fixing and centering the graphite heating element inside its sheath which considerably minimize the difficulties of mounting such a device and the problems encountered during its handling, and in that it makes it possible to achieve a long service life of the device thanks to an inert gas supply system. inexpensive, simple to implement and easy to maintain, protecting the graphite element against oxidation.
- the invention proposes in particular an electric heating device of the type defined above, characterized: in that the sheath is made of a sheet of refractory metal alloy resistant to corrosion of the medium or covered with an external metallic layer of substantially constant protection, - in that said sheath has regular corrugations arranged so that all the points of the internal surface of the sheath directly see the heating element,
- heating element is provided with two solid blocks constituting a first terminal part of said element and respectively connected to the input and output terminals of the electric current
- said graphite heating element comprises means for fixing and centering said heating element inside the sheath, said fixing and centering means comprising a insulating crown of refractory material fixed on the second end part of the graphite heating element and engaged in a cylindrical skirt fixed on the internal part of the sheath, so that a centering of the graphite element relative to the sheath at the second end part of said element is produced, and a composite sole for fixing and electrical supply of the graphite heating element removably fixed on the first end part of said element and on which are fixed bars input and output of the electrical supply current, said sole being constituted by two metal portions respectively forming the electrical input and output terminals of said graphite element, said metal portions being electrically isolated from one another and fixed rigidly to each other by means of an insulating ceramic plate.
- the latter comprises a mounting and handling plate disposed under the second end portion of the heating element, resting on the bottom of the sheath and comprising means connection with a handling rod.
- the device comprises a system for supplying the sealed chamber with a gas for protection against oxidation of the graphite heating element and extraction of said gas, connected to the sealed chamber by at least one gas inlet passage located on one of the two terminal parts of the sheath and by at least one outlet passage from the gas located on the other end part of the sheath, so that a circulation of the shielding gas can take place in said sealed chamber between the two end parts.
- the protective gas supply and extraction system includes a gas distribution box.
- the shielding gas is an inert gas such as argon.
- the ratio between the developed circumference of the sheath and the circumference of the circle passing through the vertices of the corrugations closest to the axis of the device is between 2.5 and 4.
- the outer protective layer of the sheath is obtained by a treatment called chromium-aluminization and is between a few microns and a few hundred microns thick.
- this device can be used in any fluid heating process, but it is particularly advantageous in reactors or fluidized bed furnaces.
- the device described above is produced and used in a decarbonation reactor with a fluidized bed.
- FIG. 1 is an elevational view of a heating device partially in section according to the invention
- FIG. 2 is a cross-sectional view along line II-II of FIG. 1
- FIG. 3 is a cross-sectional view along III-III of FIG. 1
- FIG. 4 is a schematic top view of FIG. 1.
- FIG. 5 is a partial section along VV of FIG. 1
- Figure 6 is a sectional view along VI-VI of Figure 1
- - Figure 7 is a partial sectional view along VII-VII of Figure 6
- Figure 8 is a partial front view of the fixing flange in FIG. 7, FIG. 9 and a partial sectional view of the other end part of the heating element and of the device of the invention
- Figure 10 is a bottom view of Figure 1
- Figure 11 is a schematic view partially in section of the device according to the invention showing an arrangement for handling the device.
- FIG. 1 represents an electric heating device according to the invention. It consists of an elongated heating element 1 made of graphite, of generally cylindrical shape. More precisely, it has a double helical shape in the heating part, and is provided with two solid parts or blocks
- the graphite element 1 is surrounded by a sheath
- the sheath is made of refractory metal alloy sheet resistant to corrosion of the medium in which it is placed and can be covered with an external protective layer 5 (see FIG. 2) of substantially constant thickness, for example 10 ⁇ m. It has regular undulations as it appears more clearly in FIGS. 2 and 3. These undulations are arranged in such that all the points on the internal surface 6 of the sheath directly "see” the heating element 1 and that the exchange surface 7 of the device with the medium is large.
- the ratio between the developed circumference of the sheath and the circumference of the circle (shown in phantom in Figure 2) passing through the top of the undulations closest to the axis of the device is between 2.5 and 4. In the embodiment shown in the figures, it is of the order of 3.5.
- the plate 10 is more precisely represented in FIGS. 4 and 5. It is a composite part based on insulating ceramic parts and different metal parts, for example in the same material as the sheath, allowing the clamping of the plate on the sheath so as to make the chamber 4 waterproof.
- the plate 10 allows the support of the heating element, the obtu ⁇ ration of the device and the electrical insulation between the terminals. More specifically, it comprises a metal part 11 provided with two passages 11a for the supply and support bars 8. Joints 11b between the upper part 3a of the sheath 3 and the part 11 ensure sealing , knowing that clamping means 11c, comprising for example Belleville rings 11d, compress the part 11 on the sheath 3.
- the part 11 also comprises a central tube 12 for discharging the inerting gas used to protect the heating element nt in graphite against oxidation.
- a clamping flange 13 provided with its clamping means 13a with differential compensation system of the Belleville washer type 13b makes it possible to compress the seals 16 with the shoulder ents 14 welded onto the bars 8 and ensuring the tightness of these bars 8 with the outside.
- Insulating ceramic parts 15a, 15b, 15c, 15d provide electrical insulation of the bars with the rest of the metal parts of the plate.
- Each part 15d is constituted by two half-cylinders, so as to allow their mounting on the bars 8.
- Seals 16 for sealing are also provided. They hold at relatively high temperatures and can for example be made of insulating material of the type known as Klingerite.
- the plate 10 By closing the device tightly, the plate 10 allows the retention of the inert gas in the retention chamber 4. Thanks to the arrangement as described of the plate 10, a good distribution of the clamping forces is achieved.
- the temperature at the plate may be of the order of 300 ° C.
- the joints may also be constituted of expanded graphite, an asbestos compound, or clean metal-plastic-like to retain its tightness properties juqu'à order the temperatures of 900 ° C. in figures 6-9 appear report crossci ⁇ cally the means for fixing and centering heating 1'eursment 1 to 1'hin of the sheath 3.
- the electrical supply bars 8 are fixed by means 20 (see FIG. 7) for screwing onto a composite sole 21 for fixing and supplying electrical power to the graphite heating element.
- the sole 21 is itself fixed to the first end portion 22 of the graphite element 1 by screws 23, screwed into tapped holes in the solid blocks 2 of the elongated heating element 1. These solid blocks remain relatively cold.
- the fixing and supply sole consists of two metal portions 24 respectively forming the electrical input and output terminals of the graphite element. These metal portions 24 are electrically insulated and rigidly fixed to each other by means of an insulating plate, for example made of ceramic, 25.
- the fixing means consist of bolts 26 coming from one side in support on the metal part (via the head for example) and the other support on the insulating material (via the nut), so that no electrical contact exists between the two metal input-output terminals (see Figure 6).
- the ceramic insulating plate can be made of any other electrically insulating material which is resistant to operating temperatures.
- the fixing means are obviously stopped, for example by folded strips 27, in accordance with the rules of the art to avoid the loss of bolts or screws inside the device.
- FIG. 9 shows the lower part of the means for fixing and centering the graphite heating element in its sheath 3.
- An insulating ring 30 made of ceramic fiber or refractory concrete constituted for example by stacks of discs is force-fitted or mechanically attached to the second end portion 31 of the heating element.
- This insulating ring engages with sufficient clearance 32, for example 5 mm, in a cylindrical skirt 33 fixed on the internal part of the sheath, inside the tops of the undulations closest to the central axis 35 of The heating element. Centering of the graphite element relative to the sheath, in the lower part of said element, is therefore achieved.
- connection means 38 for example constituted by a thread formed in a tube 39 welded to the plate 37.
- Electrical insulation means 40 and 41 rest on the plate 37 and are therefore interposed between the second end portion 31 of the heating element and the handling mounting plate 37.
- Electrical insulation means 40, 41 per ⁇ essentially eliminate the risk of contact between the graphite element 1 and the bottom of the sheath of the device, which would cause short circuits.
- FIG. 9 also shows the lower part of the system 50 for supplying the sealed chamber 4 with gas for protection against oxidation of the graphite heating element, for example in inert gas such as argon.
- This supply system 50 comprises a distribution box 51 secured to the bottom 36 of the sheath, for example by welding and, for each corrugation 52 of the sealed chamber, a passage 53 for supplying the corresponding chute 54 (defined by the concave part of the corrugation directed towards the interior of the sealed chamber) from the box 51, so that the shielding gas completely fills the sealed chamber 4.
- the distribution box 51 is supplied with inert gas via a conduit 55 secured to the sheath 3 and which goes up to the upper part of the device (see FIG. 4). It is connected to the inert gas supply means 56 (see FIG. 1) for example by a removable pipe fitted with a tight quick connector holding at high temperature.
- Means of supply 56 in inert gas comprise a device 57 (transmitter, pressure switch, etc.) for measuring and controlling the static pressure present in the pipes and the sealed chamber 4.
- An injection of additional inert gas is carried out, for example automatically, by a programmable controller 58 in the event of a pressure drop below a chosen nominal operating value.
- This function can also be fulfilled by a low pressure ano-regulator located near the immersion heater connected to the input 55 and by a valve connected to the output 12.
- the automaton also advantageously controls the electric power which supplies the heating element via terminals 9 and bars 8 from a power source 59. This source can, of course, supply several devices according to the invention.
- the sheath 3 also comprises means
- These means 70 are constituted by guide tubes
- thermocouples 72 integral with the sheath and in which are respectively placed thermocouples 72 which are connected to temperature measuring means 60 also connected to the automaton.
- the automaton is advantageously provided with a console or a control desk 61 and can be connected to calculation means 62 and data recording means 63 allowing control and monitoring of the operation of the the whole device.
- FIG. 9 there is shown a single guide tube for thermocouple, but several tubes may be provided. In general a single guide tube for lowering a thermocouple in the middle of the heating part of the graphite heating element is sufficient.
- FIG. 9 there is partially shown, under the argon distribution box 51, a centering tube fixed to the box, which allows the positioning and centering of the heating device in the oven, for example in a fluidized bed, where it is used.
- FIG 11 shows a system for mounting and handling the schematic heating element.
- a rod 80 Via the discharge tube 12 of the argon, a rod 80 is introduced, provided with a grip ring 81, which is lowered to the lower part of the device.
- This rod 80 comprises at its end a threaded part which is screwed onto the means 38 for fixing the plate 37, remaining in the sheath during operation.
- a tightening nut 82 makes it possible to lock the upper rod 80 in the upper part.
- a traveling crane it can then be handled. taking the device by its ring 81, the plate 37 coming when a pull is exerted on the rod 82, to be applied by means of the insulating discs 40, 41 on the lower part of the crown 30 secured to the graphite element. In this way, the graphite element is not likely to move inside its sheath and good rigidity of the assembly is ensured.
- a heating device of the type described above can advantageously be used in a fluidized bed reactor for a decarbonation process.
- the sheath 3 can be made of refractory metal protected by a deposit obtained by chromaluminization or by a coating known by the name of Sermetel J.
- the so-called chromaluminization process is a thermochemical treatment by diffusion.
- the parts are immersed in a cement bath composed of about 80% chromium and 20% aluminum, diluted with A O, in a proportion around 50/50.
- the Sermetel J. treatment is carried out by the company HEURCHR0ME (176, rue d'Estienne d'Orves - 92700 COLOMBES).
- Aluminum plus silicon pigment deposited cold sprayed. Steaming for fixation of the pigment on the support is then carried out to 360 ° C. a diffusion treatment around 1000 ° C the treated parts completes the process.
- the operation of the heating device described above is as follows.
- the device is introduced into its location in the fluidized bed furnace, by means of the mounting system described above.
- the mounting system is then dismantled by removing the clamping nut 82 and then unscrewing the rod 80, the mounting and handling plate 37 remaining in the sheath during operation.
- the inlet of the inerting gas for example argon
- the gas outlet pipe is put in place on the outlet standby 12 and arrangements are made to leave a slight overpressure in the chamber, so as to achieve confinement dynamics of the interior of the sheath.
- the entire inerting device is controlled by pressure sensors and the automaton 58.
- the electrical connections are made to the parts 9 of the power bars 8 then the ramp-up is carried out, controlled and controlled by the means described above and known per se.
- a relatively constant pressure is maintained inside the sealed chamber by controlling the internal pressure of the device by the controller.
- the pressure in the chamber is continuously measured and inert gas is introduced or extracted from said chamber as a function of pressure drops or pressure increases above predetermined values.
- the gas is introduced at one end and is extracted at the other end of the sheath of the device 1. This will, for reasons related to its operation, oscillate in temperature so as to maintain the bath in which it is located. a constant temperature. It follows a discontinuous circulation of the inerting gas allowing the renewal of the latter. Indeed, when the gas expands due to an increase in temperature and so that the pressure inside the sheath is kept constant, a certain quantity escapes via the circuit 56 comprising a valve.
- the chamber finds itself in depression compared to its set value, a quantity of inerting gas is then injected automatically to compensate for the loss of volume due to gas contraction. This operation allows a renewal of the required inerting gas while consuming a negligible amount.
Landscapes
- Resistance Heating (AREA)
- Furnace Details (AREA)
Abstract
Il s'agit d'un dispositif de chauffage électrique comprenant un élément chauffant allongé en graphite entouré par une gaine (3) en tôle d'alliage métallique réfractaire résistant à la corrosion ou recouverte d'une couche de protection métallique présentant des ondulations régulières. L'élément chauffant (1) comporte des moyens de fixation et de centrage comprenant une couronne isolante (30) engagée dans une jupe cylindrique (33) fixée sur la partie interne de la gaine à une des parties terminales dudit élément et une semelle composite de fixation et d'alimentation électrique de l'élément chauffant constituée par deux portions métalliques isolées électriquement et fixées rigidement l'une à l'autre par l'intermédiaire d'une plaque isolante en céramique (25).This is an electric heating device comprising an elongated graphite heating element surrounded by a sheath (3) made of refractory metal alloy sheet metal resistant to corrosion or covered with a metal protection layer having regular undulations. The heating element (1) comprises fixing and centering means comprising an insulating ring (30) engaged in a cylindrical skirt (33) fixed on the internal part of the sheath to one of the end parts of said element and a composite sole of fixing and power supply of the heating element consisting of two metal portions electrically insulated and rigidly fixed to one another by means of a ceramic insulating plate (25).
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR8714532A FR2622381B1 (en) | 1987-10-21 | 1987-10-21 | ELECTRIC HEATER |
FR8714532 | 1987-10-21 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0344245A1 true EP0344245A1 (en) | 1989-12-06 |
EP0344245B1 EP0344245B1 (en) | 1993-09-08 |
Family
ID=9356028
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP88909549A Expired - Lifetime EP0344245B1 (en) | 1987-10-21 | 1988-10-21 | Electric immersion heater |
Country Status (6)
Country | Link |
---|---|
US (1) | US5065131A (en) |
EP (1) | EP0344245B1 (en) |
CA (1) | CA1296044C (en) |
DE (1) | DE3883969T2 (en) |
FR (1) | FR2622381B1 (en) |
WO (1) | WO1989004108A1 (en) |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3916497A1 (en) * | 1989-05-20 | 1990-11-22 | Gutehoffnungshuette Man | DEVICE FOR SEALING AND FASTENING HEATING LADDERS ON ELECTRICALLY HEATED VACUUM OVENS |
FR2677840B1 (en) * | 1991-06-11 | 1993-10-15 | Propulsion Ste Europeenne | ELECTRIC HEATING RESISTANCE USING RESISTIVE ELEMENTS OF CARBON / CARBON COMPOSITE MATERIAL. |
GB2258592A (en) * | 1991-08-09 | 1993-02-10 | Paul Walter Dominic Tolkien | Inert gas protects carbon heating element |
JPH09209800A (en) * | 1996-02-05 | 1997-08-12 | Honda Motor Co Ltd | Intake air quantity control device for internal combustion engine |
US6741805B2 (en) * | 2001-09-27 | 2004-05-25 | Bai Wei Wu | Flexible graphite felt heating elements and a process for radiating infrared |
KR100752653B1 (en) * | 2006-02-01 | 2007-08-29 | 삼성전자주식회사 | Apparatus for substrate wet treating having heating part in chemical bath and method of heating chemical for substrate treating using the apparatus |
KR101329030B1 (en) * | 2010-10-01 | 2013-11-13 | 주식회사 실리콘밸류 | Fluidized Bed Reactor |
ES2724924B1 (en) * | 2016-11-18 | 2020-07-07 | Rodriguez Rodenas Jose | INTERNAL THREAD HEATING APPARATUS WITH THERMOCOPY FOR THREADED BARS |
JP6857144B2 (en) * | 2018-03-08 | 2021-04-14 | 三建産業株式会社 | How to maintain the function of the immersion heater |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR759476A (en) * | 1932-07-18 | 1934-02-03 | Carbo Keramik Ag Fa | Electric heating resistance for the production of high temperatures |
DE1269749B (en) * | 1958-09-12 | 1968-06-06 | Michael Cole | Heating cartridge for electric ovens |
US4016403A (en) * | 1975-05-01 | 1977-04-05 | National Element Inc. | Electrical heating element |
US4135053A (en) * | 1977-12-23 | 1979-01-16 | Alco Standard Corporation | Heating assembly for a heat treating furnace |
US4215233A (en) * | 1978-12-29 | 1980-07-29 | Alco Standard Corporation | Heating assembly with vibration dampening shipping supports for graphite heating elements |
DE2927280A1 (en) * | 1979-07-06 | 1981-01-08 | Eugen Jaeger Gmbh | AQUARIUM HEATER |
FR2463563A1 (en) * | 1979-08-07 | 1981-02-20 | Electric Furnace Co | Electric radial blade type heater - having independent support structure and free floating conductor strips |
FR2600855B1 (en) * | 1986-06-26 | 1988-08-05 | Electricite De France | ELECTRIC HEATING DEVICE HAVING A METAL SHEATH |
-
1987
- 1987-10-21 FR FR8714532A patent/FR2622381B1/en not_active Expired - Lifetime
-
1988
- 1988-10-21 WO PCT/FR1988/000520 patent/WO1989004108A1/en active IP Right Grant
- 1988-10-21 DE DE88909549T patent/DE3883969T2/en not_active Expired - Lifetime
- 1988-10-21 EP EP88909549A patent/EP0344245B1/en not_active Expired - Lifetime
- 1988-10-21 CA CA000580928A patent/CA1296044C/en not_active Expired - Lifetime
- 1988-10-21 US US07/381,659 patent/US5065131A/en not_active Expired - Lifetime
Non-Patent Citations (1)
Title |
---|
See references of WO8904108A1 * |
Also Published As
Publication number | Publication date |
---|---|
DE3883969D1 (en) | 1993-10-14 |
US5065131A (en) | 1991-11-12 |
FR2622381B1 (en) | 1990-03-16 |
WO1989004108A1 (en) | 1989-05-05 |
DE3883969T2 (en) | 1994-02-24 |
EP0344245B1 (en) | 1993-09-08 |
CA1296044C (en) | 1992-02-18 |
FR2622381A1 (en) | 1989-04-28 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP0004218B1 (en) | Fast nuclear reactor with at least one auxiliary heat exchanger | |
EP1561075B1 (en) | Condensation heat exchanger with plastic casing | |
EP0666104B1 (en) | Apparatus for carrying out chemical reactions which, at least during start-up, require a supply of calories | |
EP0344245B1 (en) | Electric immersion heater | |
EP0960070B1 (en) | Method and device for directly converting uranium hexafluoride into uranium oxide | |
FR2683543A1 (en) | PROCESS FOR THE THERMAL PYROLYSIS OF HYDROCARBONS USING AN ELECTRIC OVEN. | |
EP0822733A1 (en) | Induction heating apparatus and installation for continuous thermal treatment using such apparatus | |
FR2846075A1 (en) | Condensation heat exchanger for domestic application, has bundles of tubes mounted inside casing made of heat-resistant plastic material, containment mechanism to ensure mechanical containment of bundle for absorbing thrust loads | |
EP0251891B1 (en) | Electrical heating device with a metal surround | |
FR2576404A1 (en) | HEAT EXCHANGER AND APPLICATION TO A HEATING APPARATUS OF A FLUID, ESPECIALLY HEAT HOT WATER ACCUMULATOR | |
EP0053070A1 (en) | Metallurgical ladle for inductive treatment of metals | |
EP2281163B1 (en) | Method of drying and/or curing an organic coating on a continuously running metal strip, and device for implementing this method | |
EP0699224B1 (en) | Method for controlling the heat level of a solid in a heat exchanger with cylindrical tube layers | |
EP0200637B1 (en) | Apparatus for the production of a high temperature gas jet | |
WO2020084258A1 (en) | Solid oxide electrochemical system having integrated heating means | |
EP0685551A1 (en) | Internally heated rotary kiln for the pyrolysis of waste | |
CH620289A5 (en) | ||
EP0183631B1 (en) | Wall electrode for a metallurgical direct current electrical furnace | |
EP0539270B1 (en) | Process for the thermal conversion of methane and reactor for this process | |
FR2641543A1 (en) | METHOD AND DEVICE FOR VAPOCRAQUING A HYDROCARBON WITH TWO ATOMS OF CARBON AT LEAST IN A CONVECTION-HEATED TUBULAR REACTION ZONE | |
FR2469667A1 (en) | Water heater energy source conversion system - uses interspace(s) between condenser tube and sheath tube filled with thermal conductive material | |
FR2586472A1 (en) | COOKING OVEN FOR ELECTRODES, ESPECIALLY FOR ELECTRIC FUSION OVENS AND ELECTROLYTIC CELLS FOR THE PRODUCTION OF ALUMINUM | |
FR2577372A1 (en) | METHOD AND ELEMENT FOR HEATING ELECTRICALLY CONDUCTIVE FLUID, SUCH AS MOLTEN METAL | |
FR2875513A1 (en) | Protection of the ceramic sleeve of an immersion heater for a molten metal bath, notably of aluminium, using ultrasonic waves to prevent a build-up of aluminium oxide | |
EP0419351A1 (en) | Tubular electrical heating element and its bending device, and exchanger with such an element |
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: A1 Designated state(s): BE CH DE GB IT LI NL SE |
|
17P | Request for examination filed |
Effective date: 19891018 |
|
17Q | First examination report despatched |
Effective date: 19921221 |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): BE CH DE GB IT LI NL SE |
|
REF | Corresponds to: |
Ref document number: 3883969 Country of ref document: DE Date of ref document: 19931014 |
|
GBT | Gb: translation of ep patent filed (gb section 77(6)(a)/1977) |
Effective date: 19930930 |
|
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 | ||
EAL | Se: european patent in force in sweden |
Ref document number: 88909549.3 |
|
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: CH Payment date: 20021014 Year of fee payment: 15 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: BE Payment date: 20021118 Year of fee payment: 15 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: CH Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20031031 Ref country code: BE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20031031 Ref country code: LI Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20031031 |
|
BERE | Be: lapsed |
Owner name: *ELECTRICITE DE FRANCE SERVICE NATIONAL Effective date: 20031031 |
|
REG | Reference to a national code |
Ref country code: CH Ref legal event code: PL |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 20071010 Year of fee payment: 20 Ref country code: SE Payment date: 20070919 Year of fee payment: 20 Ref country code: NL Payment date: 20070618 Year of fee payment: 20 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: IT Payment date: 20071020 Year of fee payment: 20 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: GB Payment date: 20071016 Year of fee payment: 20 |
|
REG | Reference to a national code |
Ref country code: GB Ref legal event code: PE20 Expiry date: 20081020 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: NL Free format text: LAPSE BECAUSE OF EXPIRATION OF PROTECTION Effective date: 20081021 |
|
EUG | Se: european patent has lapsed | ||
NLV7 | Nl: ceased due to reaching the maximum lifetime of a patent |
Effective date: 20081021 |
|
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 EXPIRATION OF PROTECTION Effective date: 20081020 |