Industrial electric heating furnaces – Induction furnace device – For charging or discharging
Reexamination Certificate
1999-04-16
2001-05-01
Hoang, Tu Ba (Department: 3742)
Industrial electric heating furnaces
Induction furnace device
For charging or discharging
C219S632000, C373S156000, C373S154000
Reexamination Certificate
active
06226314
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a method of operating an inductor and to an assembly including an inductor for carrying out such method.
In the prior art, an inductor is water cooled during operation. For this purpose, an induction coil has a hollow cross-section which defines a cooling passage (see EP 0 291 289 B1, EP 0 339 837 B1). Such water cooling serves to protect the inductor against overheating. Water cooling has, however, the disadvantage that any leaks result in potentially harmful and in any event undesired steam generation on discharge into a melt.
DE 41 36 066 A1 discloses a discharge device for a metallurgical vessel and a method of opening and closing a discharge or outlet sleeve. An inductor is to be moved relative to the discharge sleeve into different displacement positions in order to influence thermal conduction between the inductor and the discharge sleeve. In a first displacement position, a gap between the inductor and the discharge sleeve constitutes heat insulation and the electrically switched on, cooled inductor inductively melts a metal plug in the discharge sleeve. In the second displacement position, there is a thermally conductive connection between the inductor and the discharge sleeve. The inductor through which cooling medium flows is electrically switched off. The cooling down of the discharge sleeve which thus occurs permits the metal melt to freeze in the discharge sleeve. In order to be able to operate the inductor in both these working phases (displacement positions) it must be mechanically moved. This requires an appropriate actuation and control device.
An inductor at an outlet element of a melt vessel is described in German Patent Application P 44 28 297 and is installed directly in the base of a melt vessel or in an apertured brick in the base of the melt vessel. This inductor cannot be operated in a manner corresponding to DE 41 36 066 A1 because it cannot be moved with respect to the discharge sleeve.
SUMMARY OF THE INVENTION
It is the object of the invention to provide an assembly including an inductor and a variable operating method for such inductor.
The above object is solved in accordance with the invention by the provision of a method wherein an inductor is inductively coupled to an electrically conductive component during a first working phase while cooling the inductor by a fluid. In another working phase, the inductive coupling is reduced while cooling the inductor to a different extent than during the first working phase. The inductor in accordance with the present invention is in the form of an electrically conductive induction coil having therethrough at least one cooling passage. At least one supply line is connected to the passage for the supply thereto of the cooling fluid, and at least one discharge line is connected to the passage for the discharge therefrom of the cooling fluid.
The operating method of the invention has the advantage that it may be adapted in various ways to particular operational conditions. The assembly includes a tapping device, such as a free running nozzle, a passage, a stopper valve, a sliding gate valve and a tube valve or a transport trough and/or a vessel, and the inductor can be used for heating or cooling molten material, e.g., molten metal, in such tapping device by appropriate matching of the heating capacity and the cooling capacity. It can also be used for melting or solidifying metals or non-metals, particularly non-metallic slags and/or glasses. It can also be used for heating components, containers or transport elements which come into contact with melts. It is also advantageous that the inductor need not be moved during the working phases. It can therefore be installed in the tapping device or rigidly connected thereto.
Different fluids can be used in the working phases in the described method, such as liquid gas, dry ice, water or gas, particularly compressed air. Water preferably is not used. The use of liquid gas or dry ice as the cooling medium in the working phase in which a high cooling capacity is desired is not favorable because it can result in the dangerous generation of steam or explosive gases in contact with a melt in the event of discharge and a possible leak into the liquid gas or dry ice line. In the other working phase, in which a smaller cooling capacity is sufficient, compressed air can be used as the cooling medium. The use of compressed air is favorable because it is simple to use and inexpensive and also does not lead to the problems connected with water cooling.
In an exemplary method of operation, the melt is heated up by the inductor in a first working phase in at least one tapping device of a melt vessel. The inductor can inductively couple with the tapping device or, in conjunction with an electrically non-conductive shaped component, directly with the electrically conductive melt. The first working phase thus serves to heat the melt or the tapping device. A melt plug solidified in the tapping device optionally also can be melted. The inductor operates with a very high electrical power in the first working phase so that a molten edge zone is produced on the plug before the thermal expansion of the plug takes effect so that it splits the refractory material surrounding it. The liquid edge zone layer is squeezed out by the expansion of the plug which gradually occurs. Even at these high starting powers, a fluid, for instance liquid gas or dry ice and particularly compressed air, has proved to be an adequate cooling medium.
In another working phase in which the melt flows out freely with no or only slight subsequent heating, a smaller cooling capacity is sufficient with the electrical power reduced or switched off or the inductor electrically decoupled. Cooling is effected by means of the fluid, preferably compressed air. If a plurality of tapping devices are provided adjacent one another on the melt vessel and a reduced melt flow occurs at one or a number of the tapping devices as a result of a lower temperature, these tapping devices may be subsequently heated by an increased electrical power or a decrease in the cooling capacity so that the same melt flow occurs at all the tapping devices. Thermal radiation variations may thus be compensated for.
The melt can be cooled in a further working phase. The inductor is then electrically switched off. The cooling of the inductor is continued and is preferably effected with a high cooling capacity by water, liquid gas, dry ice or compressed air. This working phase serves, in particular, to freeze the melt in the tapping device in order deliberately to interrupt the flow of melt.
It is also possible by appropriate choice of the cooling capacity to freeze melt which penetrates into any cracks in the tapping device so that the cracks are closed. It is also possible to freeze a portion of the melt as a layer on the wall of the shaped component.
REFERENCES:
patent: 2281335 (1942-04-01), Somes
patent: 2749085 (1956-08-01), Van Iperen
patent: 3403240 (1968-09-01), Henderson et al.
patent: 4535211 (1985-08-01), Carter
patent: 4673781 (1987-06-01), Nuns et al.
patent: 4805669 (1989-02-01), Lillicrap
patent: 4947895 (1990-08-01), Lillicrap
patent: 5160532 (1992-11-01), Benz et al.
patent: 5310165 (1994-05-01), Benz et al.
patent: 5348566 (1994-09-01), Sawyer et al.
patent: 5367532 (1994-11-01), Boen et al.
patent: 5391863 (1995-02-01), Schmidt
patent: 5448039 (1995-09-01), Okayama et al.
patent: 5809057 (1998-09-01), Benz et al.
patent: 5901169 (1999-05-01), Kobayashi
patent: 6051822 (2000-04-01), Bruckner et al.
patent: 6072166 (2000-06-01), Bruckner et al.
patent: 6097750 (2000-08-01), Knudsen et al.
patent: 6104742 (2000-08-01), Carter, Jr. et al.
patent: 531352 (1931-07-01), None
patent: 599 522 (1934-07-01), None
patent: 733 256 (1943-05-01), None
patent: 863 203 (1954-08-01), None
patent: 1011541 (1957-07-01), None
patent: 1200481 (1965-09-01), None
patent: 40 31 955 (1991-05-01), None
patent: 41 36 066 (1993-05-01), None
patent: 44 28 297 (1996-02-01), None
patent: 0 291 289 (1988-05-01), No
Bruckner Raimund
Grimm Daniel
Lee Steve
Didier-Werke AG
Hoang Tu Ba
Wenderoth , Lind & Ponack, L.L.P.
LandOfFree
Assembly of a tapping device and a cooled inductor does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Assembly of a tapping device and a cooled inductor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Assembly of a tapping device and a cooled inductor will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2569955