Patents by Inventor Lawrence P. Ludwig

Lawrence P. Ludwig has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 4295786
    Abstract: A gas path seal suitable for use with a turbine engine or compressor is provided. A shroud wearable or abradable by the abrasion of the rotor blades of the turbine or compressor shrouds the rotor blades. A compliant backing surrounds the shroud. The backing is a yieldingly deformable porous material covered with a thin ductile layer. A mounting fixture surrounds the backing.
    Type: Grant
    Filed: November 20, 1979
    Date of Patent: October 20, 1981
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Robert C. Bill, Lawrence P. Ludwig
  • Patent number: 4266788
    Abstract: A circumferential shaft seal comprising two sealing rings held to a rotating shaft by means of a surrounding elastomeric band. The rings are segmented and are of a rigid sealing material such as carbon or a polyimide and graphite fiber composite.
    Type: Grant
    Filed: December 7, 1979
    Date of Patent: May 12, 1981
    Assignee: The United States of America as represented by the Administrator, National Aeronautics and Space Administration
    Inventor: Lawrence P. Ludwig
  • Patent number: 4212477
    Abstract: A circumferential shaft seal comprising two sealing rings held to a rotating shaft by means of a surrounding elastomeric band. The rings are segmented and are of a rigid sealing material such as carbon or a polymide and graphite fiber composite.
    Type: Grant
    Filed: March 31, 1976
    Date of Patent: July 15, 1980
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventor: Lawrence P. Ludwig
  • Patent number: 4207024
    Abstract: A gas path seal suitable for use with a turbine engine or compressor is provided. A shroud wearable or abradable by the abrasion of the rotor blades of the turbine or compressor shrouds the rotor blades. A compliant backing surrounds the shroud. The backing is a compliant material covered with a thin ductile layer. A mounting fixture surrounds the backing.
    Type: Grant
    Filed: August 4, 1978
    Date of Patent: June 10, 1980
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Robert C. Bill, Lawrence P. Ludwig
  • Patent number: 4145058
    Abstract: A seal assembly is provided for reducing the escape of fluids from between a housing and a shaft rotatably mounted in the housing. The seal assembly comprises a pair of seal rings resiliently connected to each other and disposed in side-by-side relationship. In each seal ring, both the internal bore surface and the radial face which faces away from the other seal ring are provided with a plurality of equi-spaced recesses known as Rayleigh step pads. The seal faces referred to are located adjacent a seating surface of the housing. Under normal operating conditions, the seal assembly is stationary with respect to the housing, and the recesses generate lift, keep the assembly spaced from the rotating shaft and allow slip therebetween. Due to expansion of the shaft resulting from rubbing contact with the seal assembly, the seal assembly can seize on the shaft, and slip will then occur between the radial faces and the housing.
    Type: Grant
    Filed: July 8, 1977
    Date of Patent: March 20, 1979
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: William F. Hady, Lawrence P. Ludwig
  • Patent number: 4135851
    Abstract: A gas path seal suitable for use with a turbine engine or compressor is provided. A shroud wearable or abradable by the abrasion of the rotor blades of the turbine or compressor shrouds the rotor blades. A compliant backing surrounds the shroud. The backing may be made of corrugated sheets or the like with adjacent layers having off-set corrugations, with axes of the folds parallel to the rotor axis. The sheets may be bonded together at points of contact by brazing, welding or the like. In another embodiment a compliant material is covered with a thin ductile layer. A mounting fixture surrounds the backing.
    Type: Grant
    Filed: May 27, 1977
    Date of Patent: January 23, 1979
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Robert C. Bill, Lawrence P. Ludwig
  • Patent number: 4084825
    Abstract: This application discloses a dirt separator and excluder for removing entrained debris from gas turbine shaft seals. A helical groove pattern is constructed on the rotating shaft with the pumping pattern such that it tends to pump seal pressurizing gas toward the gas turbine seal. A second helical groove pattern is provided on the stationary housing or counter rotating member coaxial with the shaft, and this pattern is designed to provide pumping in the direction opposite from that of the groove pattern on the shaft. Gas with entrained debris entering this grooved area will be subjected to high centrifugal forces due to the swirl motion induced by the groove pattern and the rotation of the shaft. This debris is centrifuged outwardly into the outer groove pattern on the housing or counter rotating member. Since the outer groove pattern has a pumping direction opposite from that of the seal, dirt is pumped away from the seal and can be collected in a suitable debris trap remote from the seal location.
    Type: Grant
    Filed: March 31, 1976
    Date of Patent: April 18, 1978
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventor: Lawrence P. Ludwig
  • Patent number: 3953038
    Abstract: An improved fluid seal for a rotating shaft is provided which includes an inner annular ring or runner adapted to be secured to the rotating shaft and a composite sealing ring which is keyed to the inner ring and includes a radial sealing surface. An outer, nonrotating, annular ring or housing which is concentrically disposed with respect to the runner and sealing ring, includes a radial sealing surface which sealingly engages the sealing surface of the sealing ring.A circular wave spring, which is anchored to the housing and is disposed between the composite sealing ring and a snap ring secured to the housing, provides an axial force which forces the two sealing surfaces into sealing contact. The waves of the spring act as individual hydrodynamic bearings, and the axial force is transmitted across an oil film. This eliminates rubbing contact and the need for a separate thrust bearing.
    Type: Grant
    Filed: February 19, 1975
    Date of Patent: April 27, 1976
    Assignee: The United States of America as represented by the United States National Aeronautics and Space Administration
    Inventor: Lawrence P. Ludwig