Abstract: The invention relates to a safety device (1) for detecting electrode breakage in an electric arc furnace, wherein an electrode (6) is secured on an electrode support arm (4), and wherein a conduit is filled with a medium under a constant pressure and a pressure drop is produced at an electrode breakage, which is detected as an alarm signal. Here, the conduit (7a-d,3) is integrated in a protective component that is arranged beneath the electrode support arm (4) thereon, wherein in case of an electrode breakage, the conduit (7a-d,3) is damaged by a produce electric arc and the pressure drop takes place.

Abstract: A gas supply system for a side blowing and/or bottom blowing metallurgical furnace with at least one tuyere which is mounted in the side wall and/or in the bottom of the furnace, wherein gas is conveyed through a line of the gas supply system to the tuyere and through the tuyere to the interior of the metallurgical furnace and emerges there in the form of bubbles. The gas supply system has an inflow restrictor which is assigned to the tuyere or is positioned upstream of the tuyere and reduces or interrupts the gas supply to the interior of the furnace at equal intervals of time.

Abstract: To increase the efficiency in a furnace installation for melting down metallic or metal-containing charge materials, where an electrode system with a roof (6) for operating the melting-down process mainly with secondary energy can be swung into position on a lower shell part (14, 15) of a furnace (A, B), an upper shell part (17) can be swung into position on the lower shell part (14, 15) to form a premelting vessel (16). The upper shell part (17) includes a vessel wall (18) that substantially upwardly extends the vessel wall of the lower shell part (14, 15) in and additionally has a roof (7).

Abstract: The aim of the invention is to damp or suppress oscillations (?back-attack? effect) in sidewall or base blowing converters, used in particular to produce carbon steel or stainless steel. To achieve this, the gas supply system (3) for the converter comprises an inflow restrictor device (7), which is positioned upstream of or associated with the jets (5) and which periodically reduces or interrupts the gas supply to the interior of the furnace.

Abstract: The invention relates to a method for operating a melt-metallurgic furnace (2), particularly an arc furnace, during the operation of which a number of operating parameters are maintained within predetermined thresholds, wherein for this purpose a control or regulating device (1) is utilized. In order to obtain greater efficiency of the furnace, the invention provides that the control or regulating device (1) has a conventional control or regulating device (9) and a fuzzy regulating device (10), which each feed their correcting variables to a mediator (11), wherein the mediator (11) calculates the actuating signal used according to a predetermined weighting factor (F) from the correcting variable coming from the conventional control or regulating device (9) and from the fuzzy regulating device (10). The invention further relates to a melt-metallurgic furnace, particularly an arc furnace.

Abstract: A gas supply system for a side blowing and/or bottom blowing metallurgical furnace with at least one tuyere which is mounted in the side wall and/or in the bottom of the furnace, wherein gas is conveyed through a line of the gas supply system to the tuyere and through the tuyere to the interior of the metallurgical furnace and emerges there in the form of bubbles. The gas supply system has an inflow restrictor which is assigned to the tuyere or is positioned upstream of the tuyere and reduces or interrupts the gas supply to the interior of the furnace at equal intervals of time.

Abstract: The invention relates to a safety device (1) for detecting electrode breakage in an electric arc furnace, wherein an electrode (6) is secured on an electrode support arm (4), and wherein a conduit is filled with a medium under a constant pressure and a pressure drop is produced at an electrode breakage, which is detected as an alarm signal. Here, the conduit (7a-d,3) is integrated in a protective component that is arranged beneath the electrode support arm (4) thereon, wherein in case of an electrode breakage, the conduit (7a-d,3) is damaged by a produce electric arc and the pressure drop takes place.

Abstract: To increase the efficiency in a furnace installation for melting down metallic or metal-containing charge materials, where an electrode system with a roof (6) for operating the melting-down process mainly with secondary energy can be swung into position on a lower shell part (14, 15) of a furnace (A, B), an upper shell part (17) can be swung into position on the lower shell part (14, 15) to form a premelting vessel (16). The upper shell part (17) comprises a vessel wall (18) that substantially upwardly extends the vessel wall of the lower shell part (14, 15) in and additionally comprises a roof (7).

Abstract: A metallurgical vessel for a melting device for liquid metals has a vessel top, a vessel bottom provided with a collar, and an intermediate ring arranged between the vessel top and the vessel bottom. The vessel bottom receives a melt defining a melting zone within the vessel bottom and, above the melting zone, a slag zone for slag is provided. The intermediate ring is arranged at a level of the slag zone. The vessel top completely bridges the intermediate ring and is supported below the intermediate ring on the collar of the vessel bottom so that the intermediate ring is statically completely relieved of any load.

Abstract: The aim of the invention is to damp or suppress oscillations (?back-attack? effect) in sidewall or base blowing converters, used in particular to produce carbon steel or stainless steel. To achieve this, the gas supply system (3) for the converter comprises an inflow restrictor device (7), which is positioned upstream of or associated with the jets (5) and which periodically reduces or interrupts the gas supply to the interior of the furnace.

Abstract: A metallurgical vessel for a melting device for liquid metals has a vessel top, a vessel bottom provided with a collar, and an intermediate ring arranged between the vessel top and the vessel bottom. The vessel bottom receives a melt defining a melting zone within the vessel bottom and, above the melting zone, a slag zone for slag is provided. The intermediate ring is arranged at a level of the slag zone. The vessel top completely bridges the intermediate ring and is supported below the intermediate ring on the collar of the vessel bottom so that the intermediate ring is statically completely relieved of any load.

Abstract: The invention concerns a replacement method and a device for assembling and disassembling modules of an electric arc furnace. Said method consists in lifting and pivoting the furnace cover or in only lifting it; when disassembling, it consists in removing the agent and power supply ducts as well as the instrument leads of the upper container (3) and/or of the lower container (2) and, after assembling in connecting them. The invention aims at enabling use of a low-power load crane and in significantly reducing replacement time. Therefor, once the lower container has been detached (2), the upper container (3) remains in its position, or once the energy agent supply ducts and the instrument leads have been detached, the upper container is lifted and detached by the loading crane.

Abstract: The aim of the invention is to improve the cooling of the bottom electrodes (1) of metallurgical melting vessels. To this end, a cooling plate (5) is situated beneath the support plate (2) on which the contact elements (3) are supported. The cooling plate is set apart from the support plate. This forms a cooling chamber (4) through which a cooling medium flows, the cooling effect of said medium being reinforced by cooling ribs (6). Said cooling ribs are situated in the cooling chamber (4) and are welded to the support plate (2) and preferably, also to the cooling plate (5).

Abstract: The aim of the invention is to provide a means of also cooling the lower part of electric arc furnaces and/or resistance furnaces. To this end, said lower part—the actual melting vessel (4)—is surrounded with a jacket (9) at a certain distance, forming a shell, and the resulting intermediate space is configured as a cooling device (10) and subjected to the action of a cooling medium (14).

Abstract: The invention relates to the emptying of melting vessels (1) by tipping. According to the invention, the melting vessel (1) is placed on column-shaped bases (6). During the tipping process, the melting vessel (1) is raised at the side and the base supports (7) of the opposite side are used as the pivot or axis of rotation. This ensures that the discharge opening (4) and the slag overflow edge (5) are not moved very far from their original position.

Abstract: A water-cooled multipart hood for metallurgical vessels, particularly pouring ladles, with cooling tubes arranged welded tube against tube and/or with gaps between the tubes, with an opening arranged in the cover of the hood for inserting a refractory core piece for guiding electrodes therethrough, and with openings for discharging flue gases. The water-cooled ladle hood further includes a lower outer hood and a lower inner hood with at least three gas exhaust openings and a gas conducting pipe arranged in the lower outer hood, wherein an upper hood with at least three gas exhaust openings, a gas conducting pipe and an opening is arranged in the lower inner hood.

Abstract: The subject invention relates to defective, interfering HIV particles and uses thereof. In particular, these particles encode a membrane bound receptor protein, as well as multitarget ribozymes, which together interfere with the production of infectious HIV by a host cell by downregulating the amount of HIV envelope protein on the surface of the cell as well as the amount of HIV genomic RNA.

Abstract: A bottom electrode (1) for d.c. arc furnaces with metal rods (3) arranged on the base plate (2) of the bottom electrode and with conductive and nonconductive layers formed of high temperature-resistant refractory material introduced between them. An upper layer formed of conductive bricks (8), a middle layer formed of conductive, monolithic lining material (9), and a lower layer formed of a nonconductive insulating mass (10) are introduced via the circumference of the base plate (2). In the area of the bricks (8), the metal rods (3) are additionally embedded in a nonconductive mass (11). To introduce inert gases to purge the melt through the bottom electrode (1), the metal rods (3) are provided with a cored hole and, in the upper part, with a number of radial holes in order for the purging gases to be able to be discharged in the area of the bricks (8), or blind holes (13), which are connected to a second purging gas line (13a), are introduced into the lower part of the lined bottom electrode (1).

Abstract: A hearth for use in a furnace, which comprises an upper layer of magnesia containing chromic oxide, a lower layer containing graphite and an organic bonding agent, and an intermediate layer of a mixture of the materials forming the upper and lower layers. The hearth is particularly useful in DC arc funaces, in which steel rods embedded in the bottom act as the anode. The hearth has improved service durability.

Abstract: In a direct-current arc furnace, the service life of the bottom electrode can be extended substantially, if the cooling unit cooling the bottom electrode during the melting operations is not switched off during longer stoppages, as has been customary thus far, but continues to be operated at a reduced cooling output during at least a part of the stoppage. The cooling unit is preferably controlled during the stoppage according to such a program and in dependence of the respective measured temperature of the bottom electrode, so that the temperature of the bottom electrode is maintained within a preset range.