Patents Assigned to Leybold Durferrit GmbH
  • Patent number: 6085827
    Abstract: A casting apparatus has within a heating chamber (6) and a mold (5) which can be removed from the heating chamber into a molten quenching metal (10) disposed underneath it. As a thermal barrier between the heating chamber (6) and the quenching metal (10), a thermal insulating layer (13) floating on the molten quenching metal (10) is provided, through which the mold (5) plunges into the molten quenching metal (10).
    Type: Grant
    Filed: November 16, 1993
    Date of Patent: July 11, 2000
    Assignee: Leybold Durferrit GmbH
    Inventor: Franz Hugo
  • Patent number: 5544194
    Abstract: Apparatus for the cleaning, especially degreasing, of electrically conductive material (9), for example metal and/or ceramic turning chips and/or grinding sludges, under vacuum conditions, essentially consisting of a container (4) and at least two electrodes (4,5) which are connected to a power supply unit (8), the material (9) to be cleaned being heatable by the two electrodes (4,5) by direct passage of current.
    Type: Grant
    Filed: September 23, 1994
    Date of Patent: August 6, 1996
    Assignee: Leybold Durferrit GmbH
    Inventors: Franz Hugo, Erwin Wanetzky
  • Patent number: 5505008
    Abstract: Material containing organic substances including rubber, plastic, and lacquer is heated in a vacuum process chamber at subatmospheric pressure in a nonreactive atmosphere to a temperature of at least 200.degree. C., the gases and vapors thus formed are condensed in a condensate separator, and the condensate is captured and made available for reuse or disposal. The embrittled residues formed from these substances are crushed and the crushed residues are collected and made available for recycling or disposal. If metals are contained in the material, the residues are loosened, collected, and crushed. The process and the apparatus are suitable for recycling insulted wire, metal bonded to rubber, plastic containers decorated with pigments, motor vehicle steering wheels, workpiece hangers and tools coated with lacquer, poorly lacquered metal parts, tires and rubber pads of track-laying vehicles, and seals.
    Type: Grant
    Filed: June 23, 1994
    Date of Patent: April 9, 1996
    Assignee: Leybold Durferrit GmbH
    Inventors: Franz Hugo, Helmut Teuschel, Erwin Wanetzky
  • Patent number: 5503215
    Abstract: A furnace chamber (2) has a lock (14) provided with two sealing plates (18, 22), a melting furnace (3), and a casting mold carrier (25), which can be moved horizontally through the lock (14) in the horizontal direction into a casting position (34) in the furnace chamber. An outer sealing plate (22) is mounted on a first truck (21), carrying a first rail segment (23) for a second truck (24) on the other side of the sealing plate (22), the casting mold carrier (25) being mounted on this second truck. A horizontal drive (27) is used to move the second truck (24) with respect to the first (21), and in the interior of the furnace chamber (2) there is a second rail segment (32) to which the casting mold carrier (25) is transferred from the first rail segment (23). A heating chamber (8) can be raised and lowered above the casting position (34) in the furnace chamber, which is equipped with a filling hole (12) and with heating elements (35, 36, 37).
    Type: Grant
    Filed: May 5, 1995
    Date of Patent: April 2, 1996
    Assignee: Leybold Durferrit GmbH
    Inventors: Ulrich Betz, Alfred Henn, Franz Hugo, Wolfgang Reuter
  • Patent number: 5480127
    Abstract: In a method for melting and treating metals and metal alloys, especially steels, solid charge material is melted in a ladle. Then while passing a gas through the melt at least part of the time, at least one of the treatments of decarburization, dephosphorization, deoxidation, desulfurization, alloying and removing nonmetallic inclusions is performed in the same ladle. An apparatus for the practice of the method has two tracks (W1, W2) for the ladle (5), which are aligned in an approximate T-shape to one another, a preheating station (9) and a slag removal station (14) being arranged in the top part of the T and, at the intersection between the top part and the stem between the preheating station (9) and the slag removal station (14), the first treatment station (10) with a heating system is disposed, and at the free end of the stem of the T a second treatment station (16) for the vacuum treatment is disposed.
    Type: Grant
    Filed: December 1, 1994
    Date of Patent: January 2, 1996
    Assignee: Leybold Durferrit GmbH
    Inventors: Alok Choudhury, Jochen Schumann, Harald Scholz, Jan-Erwin Schindler
  • Patent number: 5479438
    Abstract: In a melting crucible (3) a central bottom portion (27) is formed of a plurality of palisades (5) and is shaped so that the palisades together form a vessel or a pot (7) having a centrally disposed spout or outlet (8). Two independently powered induction coils (10, 11) are provided, one coil (10) externally surrounding the collar or upper part of the central bottom portion (27), and the other coil (11) externally surrounding the spout (8). The palisades (5) are separated from one another by individual gaps (6) running radially outwardly from the center, while the electromagnetic field of at least the upper coil (10) acts on the charge contained in the melting crucible through the gaps (6).
    Type: Grant
    Filed: June 23, 1994
    Date of Patent: December 26, 1995
    Assignee: Leybold Durferrit GmbH
    Inventors: Mathias Blum, Alok Choudhury, Hans-Gunter Fellmann, Wilfried Goy, Franz Hugo, Felix Muller, Wolfgang Schwarz, Hardy Weisweiler
  • Patent number: 5478057
    Abstract: In a furnace operated with hydrogen gas as a cooling gas under positive pressure for the hardening of metallic workpieces, with a housing (2) enclosing a heating chamber for accepting a batch of workpieces, this housing being connected to a vacuum pump and being openable by way of a bottom housing cover (3) Cooling gas is circulated through gas outlets and outlets opening into the heating chamber by the impeller of a motor-blower unit. A heating system is provided on the bottom section (78) of a batch table (8) supported on the housing cover (3) and rotable around a vertical axis (A). A grate formed of bars (34) is mounted above the heating system (37) for supporting the batch of workpieces, and insulating plates (43, 44) are installed underneath the heating system (37).
    Type: Grant
    Filed: December 14, 1994
    Date of Patent: December 26, 1995
    Assignee: Leybold Durferrit GmbH
    Inventors: Bernhard Wilhelmi, Horst Gerdes
  • Patent number: 5445789
    Abstract: A plunger charged as an electrode is received in a trough charged as a counter-electrode in order to heat material in the trough above the annealing temperature of metal material or the sintering temperature of ceramic-material. The trough and plunger are situated in a vacuum chamber separated from a condenser and pump stand by a valve. The plunger can be retracted into a cover of the chamber by a hydraulic drive on the cover. The cover, drive, and plunger are removable from the lower part of the chamber as a unit.
    Type: Grant
    Filed: March 16, 1994
    Date of Patent: August 29, 1995
    Assignee: Leybold Durferrit GmbH
    Inventors: Erwin Wanetzky, Franz Hugo
  • Patent number: 5425047
    Abstract: An induction furnace with a crucible having a crucible axis, an induction coil and a furnace body containing a gas-tight jacket, and also with a cover which can be placed on the furnace body and has at least one gas connection, a charging valve and a pouring apparatus, the furnace body and cover being joined together releasably but hermetically by a flange connection, and being journaled in the joined state in a furnace frame by a tilting mechanism which engages the cover, and after the flange connection is separated the cover body can be removed from the furnace body which remains in the furnace frame.
    Type: Grant
    Filed: March 25, 1993
    Date of Patent: June 13, 1995
    Assignee: Leybold Durferrit GmbH
    Inventors: Ulrich Betz, Hans Kemmer, Martin Lorke, Klaus Pfeuffer, Otto Stenzel
  • Patent number: 5416793
    Abstract: A crucible 1 of an induction melting apparatus has a cover 3 closing the crucible off hermetically and having a connection 5 for attaching the cover to a vacuum source 6. At the bottom the crucible 1 has a prolongation 7 in which a mold 9 is sealingly disposed. Thus, the mold 9 is evacuated together with the crucible 1 so that a vacuum chamber enveloping the crucible 1 and the mold (9) is unnecessary.
    Type: Grant
    Filed: May 14, 1993
    Date of Patent: May 16, 1995
    Assignee: Leybold Durferrit GmbH
    Inventors: Franz Hugo, Hans G. Fellmann
  • Patent number: 5383980
    Abstract: Workpieces of steel are hardened by carburizing the surface and then quenching. The carburizing is performed by means of a plasma discharge in a vacuum, in the presence of gaseous hydrocarbons at voltages between 200 and 2000 volts, preferably between 300 and 1000 volts, and preferably with the admixture of argon. The plasma is produced by means of electrodes operated in a vacuum, the cathode of which serves as workpiece holder and is operated by pulsed operation. In order to achieve a uniform hardness distribution and to reduce the mass flow of carbon, even in the case of irregularly shaped workpieces, the carburization is performed at a total pressure between 14 and 30 mbar, the pulse duration is selected between 110 and 10,000 .mu.sec, and the pause duration is selected between 30 and 10,000 .mu.sec.
    Type: Grant
    Filed: April 29, 1993
    Date of Patent: January 24, 1995
    Assignee: Leybold Durferrit GmbH
    Inventors: Albrecht Melber, Kyong-Tschong Rie, Frank Schnatbaum
  • Patent number: 5372655
    Abstract: Method for the treatment of alloy steels and refractory metals such as Ti, Zr and Nb, especially for depassivation and subsequent thermochemical surface treatment in a process chamber (1, 2) under the action of pressure and temperature, wherein, in a first process step, a first gas or gas mixture from the group N.sub.2, H.sub.2 or NH.sub.3 is admitted for the depassivation into a process chamber (1), a pressure greater than 1 bar a and a temperature between 100.degree. C. and 1,000.degree. C. is established in the chamber (1), and in a second process step a second gas or gas mixture from the group of N-, C- or B-containing gases is admitted into a process chamber (1, 2) for the thermochemical surface treatment, and a temperature between 100.degree. C. and 1,000.degree. C. at a pressure greater than or equal to 1 bar a is established.
    Type: Grant
    Filed: April 14, 1992
    Date of Patent: December 13, 1994
    Assignee: Leybold Durferrit GmbH
    Inventors: Friedrich Preisser, Peter Minarski, Albrecht Melber, Klaus Zimmerman
  • Patent number: 5343492
    Abstract: A crucible (9) surrounded by an induction coil (10) is housed for tilting about a first tilt axis within a gas-tight furnace chamber (2) which has a closable opening (40a) for transferring the melt (31) into a receiving vessel (36, 63). The furnace chamber (2) is in turn tiltable about a second tilt axis (A2) between a melting position and a position in which the start of the pouring of the melt is immediately imminent by an angle which corresponds to the range of the tilting angle of the crucible (9). The opening (40a) for transferring the melt is surrounded by a first sealing flange (41) which, after the tilting path of the furnace chamber (2) has been traveled, comes sealingly into contact with a second sealing flange (38, 64) of an additional gas-tight chamber (35, 61) in which the receiving vessel (36, 63) for the melt is situated.
    Type: Grant
    Filed: May 5, 1993
    Date of Patent: August 30, 1994
    Assignee: Leybold Durferrit GmbH
    Inventor: Alfred Henn
  • Patent number: 5294096
    Abstract: The feed line (7) and the return line (8) are combined to a single current supply line (6) at one end of the coil which leads to the first turn sections connected to the opposite end of the coil. Second turn sections running back to the supply line (6) are radially opposed from respective first turn sections.
    Type: Grant
    Filed: April 14, 1992
    Date of Patent: March 15, 1994
    Assignee: Leybold Durferrit GmbH
    Inventor: Felix Muller
  • Patent number: 5280847
    Abstract: A teeming spout has on its inside a plurality of picket-like metal segments (1) separated from one another by slots (2) and is externally surrounded by an induction coil (3). The bottom turn (7) of this induction coil (3) has a downwardly directed pitch equalization piece (8) which provides such that the field acts uniformly on the teeming stream from all sides and therefore it is not deflected.
    Type: Grant
    Filed: January 13, 1993
    Date of Patent: January 25, 1994
    Assignee: Leybold Durferrit GmbH
    Inventors: Matthias Blum, Wilfried Goy, Erich Zuckerstatter
  • Patent number: 5281781
    Abstract: Apparatus for switching a high-current power supply, for example for transportable melting systems in melting and remelting plants, with a stationary apparatus part and a movable apparatus part, a contact surface between the stationary and the movable part as well as a device for locking the two parts, the contact surface (2d) on the stationary part (S) being preferably in the form of a hemisphere (2a) and the corresponding contact surface (3d) on the movable part (M) being preferably configured as a conical inside surface (3a) and the contacts being joinable forcibly with one another by means of a clamping device, the clamping device consisting for example of a centering and drawing bolt (2b) and of a corresponding ball clamping device, and that the clamping device is electrically insulated by means of insulators (7, 12) from the current-carrying contacts.
    Type: Grant
    Filed: September 30, 1991
    Date of Patent: January 25, 1994
    Assignee: Leybold Durferrit GmbH
    Inventors: Karl Herchenrother, Michael Protzmann, Heiko W. Spengemann
  • Patent number: 5271033
    Abstract: A furnace chamber contains a chassis to which a closure plate for said chamber is removably fixed. A tilting frame is borne by said chassis in a pair of coaxial tilting bearings, one of which incorporates a rotary lead through for power lines and cooling lines to an induction coil surrounding a crucible on the tilting frame. The chassis includes a pair of rails which are movable horizontally on wheels mounted to the floor of the furnace chamber.
    Type: Grant
    Filed: August 11, 1992
    Date of Patent: December 14, 1993
    Assignee: Leybold Durferrit GmbH
    Inventors: Daniel Bethge, Alfred Henn, Michael Schaefer, Hans-Johann Kemmer, Otto Stenzel
  • Patent number: 5260966
    Abstract: A remelting furnace has a crucible (2) and a raisable pot (3) placed thereon. An electrode rod (6) leads into the pot (3) through a stuffing box (8) borne by a lower platform (9). The lower platform (9) is carried by rods (12, 13) which are fastened each at its upper end to a weighing platform (14). The connection of the lower platform (9) to the particular rod (12, 13) is performed in each case through a releasable clutch (10,11 ). Consequently, a lifter (17) can lift the pot (3) such that it shifts upwardly with the bottom platform (9) relative to the rods (12, 13).
    Type: Grant
    Filed: August 26, 1992
    Date of Patent: November 9, 1993
    Assignee: Leybold Durferrit GmbH
    Inventor: Peter Schottlaender
  • Patent number: 5234486
    Abstract: For the remelting of titanium or zirconium, the electroslag remelting method is used. To prevent any reaction of the melt with oxygen or nitrogen, the remelting is performed in an inert gas atmosphere. Fluorspar with an addition of calcium oxide is used as the slag forming substance. This calcium oxide dissolves in the fluorspar and reacts with oxygen, nitrogen and hydrogen in the titanium, so that the reactive metal is purified of these substances.
    Type: Grant
    Filed: August 4, 1992
    Date of Patent: August 10, 1993
    Assignee: Leybold Durferrit GmbH
    Inventors: Alok Choudhury, Norbert Ludwig, Harald Scholz
  • Patent number: 5225142
    Abstract: In a vacuum heat treating oven operating with hydrogen under pressure as the cooling medium, especially for the quenching of greatly heated metal workpieces (5), a method is provided for the automatic control of the progress of the process and for monitoring safety of operation. The housing (4) of the heat treating oven is for this purpose connected to gas inlet lines (9 and 10), one for the admission of the cooling gas and one for the admission of the flushing gas (H.sub.2 and N.sub.
    Type: Grant
    Filed: October 7, 1991
    Date of Patent: July 6, 1993
    Assignee: Leybold Durferrit GmbH
    Inventors: Paul Heilmann, Peter Minarski, Friedrich Preisser