Patents Assigned to Liberty Technology Center, Inc.
  • Patent number: 5197338
    Abstract: A system for determining torque generated by a motor actuated operator driving a partial turn valve including a torque ring replacing the cover of the operator housing, a frictional shaft coupling member coupling the inner circumferential surface of the drive sleeve within the operator housing to the central shaft of a torque plug projecting from the operator through the torque ring. Two or more stops are provided projecting from the torque ring on either side of the central shaft. A cross member is provided extending radially outwardly from the central shaft of the torque plug to contact each of the stops when the operator is driven. A sensor, preferably an array of strain gauges mounted to the central shaft, generates a signal proportional to the torque applied by the operator to the operator housing through the frictional shaft coupling and the torque plug.
    Type: Grant
    Filed: July 22, 1991
    Date of Patent: March 30, 1993
    Assignee: Liberty Technology Center, Inc.
    Inventors: Stephen M. Heiman, Michael J. Delzingaro
  • Patent number: 5140263
    Abstract: A system to determine the position of an electrically conductive element movably positioned in a housing, like a metal disc in a check valve, with greater accuracy and resolution than single magnet systems includes first and second A.C. electromagnets positioned in close proximity to the element on opposing sides of the housing. The magnets are excited with A.C. currents to generate magnetic fields which penetrate the housing and the element. The magnetic fields are sensed by a magnetic field sensor. A control portion of the system includes a microprocessor configured to allow an operator to adjustably select and set a common frequency, individual amplitudes and a phase difference between the two currents supplied to the two magnets so that the currents might be adjusted to cause the magnets to generate magnetic fields at least partially and preferably essentially cancelling one another at the sensor.
    Type: Grant
    Filed: November 27, 1991
    Date of Patent: August 18, 1992
    Assignee: Liberty Technology Center, Inc.
    Inventor: Robert L. Leon
  • Patent number: 5086273
    Abstract: A system to determine the position of an electrically conductive element movably positioned in a housing, like a metal disc in a check valve, includes an A.C. electromagnet positioned in close proximity to the valve casing and the disc. The magnet is excited with an A.C. voltage to generate a magnetic field which penetrates the casing and the disc. The magnetic field is detected by a sensor. A.C. current and voltage signals from the electromagnet and a magnetic field signal from the sensor are presented to a processor portion of the system. The processor portion digitizes, amplitude and phase modulates each of the three signals and generates four traces: A.C. current amplitude, magnetic field amplitude, A.C. current phase and magnetic field phase. The latter two traces are derived with respect to an A.C. voltage phase signal. Comparable baseline signals previously gathered for the valve are stored.
    Type: Grant
    Filed: April 20, 1990
    Date of Patent: February 4, 1992
    Assignee: Liberty Technology Center, Inc.
    Inventor: Robert L. Leon
  • Patent number: 5029597
    Abstract: A controller for controlling the operation of a motor operated valve combination, including a valve yoke, a valve stem, a valve disc, a valve seat and a motor operator having a motor and drive means interconnecting the motor to the valve stem for movement of the valve stem in a first direction to move the valve disc into engagement with the valve seat for closing the valve. The controller comprises a sensor for sensing forces experienced by the valve stem during valve closing and for generating related electrical signals. A first detector is employed for receiving the electrical signals from the sensor, for determining when the rate of change in the valve stem forces exceed a first predetermined limit and for generating an electrical signal when the first predetermined limit is exceeded.
    Type: Grant
    Filed: January 22, 1990
    Date of Patent: July 9, 1991
    Assignee: Liberty Technology Center, Inc.
    Inventor: Robert L. Leon
  • Patent number: 5020773
    Abstract: A monitoring system for use with a conventional actuator system which includes an actuator and control system. The monitoring system comprises a wiring harness including at least three and preferably five ring type current sensors, such as current transformers or Hall effect devices, which are permanently mounted on various leads associated with the control system. The sensors sense currents carried on the leads which are indicative of the state of control system switches connected with the leads. The sensors generate signals responsive to the currents and indicative of the switch states. Each of the sensors is spaced from and wired to a single electrical connector. The connector is adapted to removably mate with a complementary connector to simultaneously electrically couple the complementary connector with each wired sensor.
    Type: Grant
    Filed: January 22, 1990
    Date of Patent: June 4, 1991
    Assignee: Liberty Technology Center, Inc.
    Inventors: Richard H. Tuft, Robert L. Leon
  • Patent number: 5008841
    Abstract: A non-invasive system and method is provided for the inspection of check valves which combines acoustic and magnetic techniques. The acoustic and magnetic techniques are used to measure check valve disk motion and internal impacts or vibrations resulting from the disk motion.
    Type: Grant
    Filed: July 28, 1989
    Date of Patent: April 16, 1991
    Assignee: Liberty Technology Center, Inc.
    Inventor: John W. McElroy
  • Patent number: 4911004
    Abstract: Devices and methods for determining axial loads on a generally cylindrical member include a clamp portion removably attached by clamping to a portion of a generally cylindrical load-bearing member. The clamp portion of the device moves in response to diametral deformations in the clamped portion of the cylindrical member. A sensor is provided to sense movement of the clamp portion of the device in response to diametral deformations in the portion of the cylindrical member. The sensor generates signals related to the magnitude of the sensed movement and thus the sensed diametral deformations. The sensed movement may be bending in the clamp portion of the device or distance changes between parts of the clamp portion of the device. A signal storage device, which may also be a computer, stores the signals for real time or delayed determination of axial loading in the member.
    Type: Grant
    Filed: August 15, 1988
    Date of Patent: March 27, 1990
    Assignee: Liberty Technology Center, Inc.
    Inventor: Robert L. Leon
  • Patent number: 4898362
    Abstract: The present invention comprises a thrust actuated control for use in a motor operated valve having a motor operator including a motor drive, a stem nut coupled to the motor drive for rotation about an axis and a stem nut lock coupled to the motor drive for preventing axial movement of the stem nut. The valve includes a valve gate, a valve seat and a valve stem coupled to the valve gate, the valve stem threadingly engaging the stem nut for axial movement in a first direction upon rotation of the stem nut in a first direction to move the valve gate toward and into engagement with the valve seat and for axial movement in a second direction upon rotation of the stem nut in a second direction to move the valve gate out of engagement with and away from the valve seat.
    Type: Grant
    Filed: January 31, 1989
    Date of Patent: February 6, 1990
    Assignee: Liberty Technology Center, Inc.
    Inventor: Robert L. Leon
  • Patent number: 4882937
    Abstract: A strain sensor device is disclosed for attachment to a structural member for measuring strains experienced by the member along a strain axis. The strain sensor device comprises a tensile strain member secured to the structural member generally parallel to the strain axis. Two strain gages are secured to the tensile strain member, one of the strain gages being longitudinally oriented with respect to the strain member to experience longitudinal strain and the other of the strain gages being transversely oriented with respect to the strain member to experience Poisson strain. The two strain gages comprise a strain gage bridge circuit for generating electrical signals proportional to strains sensed in the structural member.
    Type: Grant
    Filed: November 14, 1988
    Date of Patent: November 28, 1989
    Assignee: Liberty Technology Center, Inc.
    Inventor: Robert L. Leon
  • Patent number: 4879901
    Abstract: A device for measuring and indicating the forces on a valve stem over at least a portion of the valve strokes is comprised of a strain sensor secured to the valve yoke for sensing strains experienced by the valve yoke. The sensed strains are proportional to the forces on the valve yoke and are equal but opposite to the forces on the valve stem. The strain sensor generates electrical signals proportional to the forces on the valve stem. In one embodiment, a second strain sensor is secured to the valve operator for sensing strains experiences by the valve operator and for generating proportional electrical signals. A display, electrically connected to the strain sensors, is provided for receiving the generated electrical signals and for indicating the forces on the valve stem and the forces on the valve operator.
    Type: Grant
    Filed: April 22, 1988
    Date of Patent: November 14, 1989
    Assignee: Liberty Technology Center, Inc.
    Inventor: Robert L. Leon
  • Patent number: 4879511
    Abstract: A device is disclosed for in situ detecting of axial motion of a generally cylindrical member in which both ends of the member are unavailable for the installation of a prewound coil. The device comprises a predetermined length of generally flat multiconductor cable. A first connector component is secured to one end of the cable, the first connector component having a plurality of electrical contacts, the number of contacts being at least two greater than the number of conductors of the cable. A second connector component is secured to the other end of the cable, the second connector component having a plurality of electrical contacts, the number of contacts being at least two greater than the number of conductors of the cable.
    Type: Grant
    Filed: October 31, 1988
    Date of Patent: November 7, 1989
    Assignee: Liberty Technology Center, Inc.
    Inventor: Robert L. Leon
  • Patent number: 4805451
    Abstract: A device for measuring and indicating the forces on a valve stem over at least a portion of the valve strokes is comprised of a strain sensor secured to the valve yoke for sensing strains experienced by the valve yoke. The sensed strains are proportional to the forces on the valve yoke and are equal but opposite to the forces on the valve stem. The strain sensor generates electrical signals proportional to the forces on the valve stem. A display, electrically connected to the strain sensor, is provided for receiving the generated electrical signals and for indicating the forces on the valve stem. A system for evaluating the performance of a valve and valve operator also utilizes the yoke strain sensor in combination with other sensors, including a valve stem motion sensor, a spring pack motion sensor, a motor current sensor and, possibly, a stem strain sensor, as well as an indicator of the condition of torque and limit switches.
    Type: Grant
    Filed: August 20, 1987
    Date of Patent: February 21, 1989
    Assignee: Liberty Technology Center, Inc.
    Inventor: Robert L. Leon