Patents by Inventor Keith Johnston

Keith Johnston 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).

  • Publication number: 20220316209
    Abstract: A ceiling system which includes support beams, elongated covers that at least partially cove the support beams, and baffles which attach to the support beams. The support beams may have a vertical web portion, a flange portion at a top end of the vertical web portion, and bulb portion at a bottom end of the vertical web portion. The elongated may have a cover body and a cover slot in a top surface of the cover body. The elongated covers may be mounted to the support beams so that the bulb portions of the support beams are located within the cover slots of the elongated covers. The baffles may extend between and be mounted to adjacent ones of the plurality of support beams so that the baffles extends into notches of the elongated covers and the bulb portions of the support beams are located within slots of the baffle.
    Type: Application
    Filed: March 25, 2022
    Publication date: October 6, 2022
    Inventors: Chris Kabatsi, Robert Kilian, Kevin Kane, John Johnston, Moti Tavassoli, Keith Berry
  • Patent number: 10788260
    Abstract: Described herein is a method of removing refrigerant from a natural gas liquefaction system in which vaporized mixed refrigerant is withdrawn from the closed-loop refrigeration circuit and introduced into a distillation column so as to be separated into an overhead vapor enriched in methane and a bottoms liquid enriched in heavier components. Overhead vapor is withdrawn from the distillation column to form a methane enriched stream that is removed from the liquefaction system, and bottoms liquid is reintroduced from the distillation column into the closed-loop refrigeration circuit. Also described are methods of altering the rate of production in a natural gas liquefaction system in which refrigerant is removed as described above, and a natural gas liquefaction systems in which such methods can be carried out.
    Type: Grant
    Filed: August 8, 2017
    Date of Patent: September 29, 2020
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Brian Keith Johnston, Gowri Krishnamurthy, Mark Julian Roberts
  • Patent number: 10393429
    Abstract: A method for controlling the flow of natural gas and refrigerant in the main heat exchanger of a natural gas liquefaction facility. The method provides for the automated control of a flow rate of a natural gas feed stream through a heat exchanger based on one or more process variables and set points. The flow rate of refrigerant streams through the heat exchanger is controlled by different process variables and set points, and is controlled independently of the flow rate of the natural gas feed stream.
    Type: Grant
    Filed: April 6, 2016
    Date of Patent: August 27, 2019
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Fei Chen, Brian Keith Johnston, Mark Julian Roberts
  • Patent number: 9927827
    Abstract: A photovoltaic (PV) system can include one or more trackers that each includes a plurality of rows of PV collection devices. The rows of PV collection devices can be electrically independent from one another.
    Type: Grant
    Filed: October 31, 2014
    Date of Patent: March 27, 2018
    Assignee: SunPower Corporation
    Inventors: Keith Johnston, Nicholas Ford
  • Patent number: 9923374
    Abstract: A photovoltaic system includes solar cells and an inverter configured to convert direct current generated by the solar cells to alternating current. The photovoltaic system includes a maximum power point (MPP) tracking module configured to perform MPP tracking for the photovoltaic system. The MPP tracking module is configured to detect shading of the solar cells and to modify its MPP tracking to prevent tracking of local MPPs. The MPP tracking module may be incorporated in the inverter.
    Type: Grant
    Filed: June 14, 2016
    Date of Patent: March 20, 2018
    Assignee: SunPower Corporation
    Inventors: Zachary S. Judkins, Keith Johnston
  • Publication number: 20180058752
    Abstract: Described herein is a method of removing refrigerant from a natural gas liquefaction system in which vaporized mixed refrigerant is withdrawn from the closed-loop refrigeration circuit and introduced into a distillation column so as to be separated into an overhead vapor enriched in methane and a bottoms liquid enriched in heavier components. Overhead vapor is withdrawn from the distillation column to form a methane enriched stream that is removed from the liquefaction system, and bottoms liquid is reintroduced from the distillation column into the closed-loop refrigeration circuit. Also described are methods of altering the rate of production in a natural gas liquefaction system in which refrigerant is removed as described above, and a natural gas liquefaction systems in which such methods can be carried out.
    Type: Application
    Filed: August 8, 2017
    Publication date: March 1, 2018
    Applicant: AIR PRODUCTS AND CHEMICALS, INC.
    Inventors: Brian Keith Johnston, Gowri Krishnamurthy, Mark Julian Roberts
  • Publication number: 20170292783
    Abstract: A method for controlling the flow of natural gas and refrigerant in the main heat exchanger of a natural gas liquefaction facility. The method provides for the automated control of a flow rate of a natural gas feed stream through a heat exchanger based on one or more process variables and set points. The flow rate of refrigerant streams through the heat exchanger is controlled by different process variables and set points, and is controlled independently of the flow rate of the natural gas feed stream.
    Type: Application
    Filed: April 6, 2016
    Publication date: October 12, 2017
    Applicant: Air Products and Chemicals, Inc.
    Inventors: Fei Chen, Brian Keith Johnston, Mark Julian Roberts
  • Patent number: 9735729
    Abstract: A photovoltaic string may include an open circuit voltage limiter that conducts current in one direction to provide a limiter voltage less than an open circuit voltage of the photovoltaic string, and that conducts current in the other direction. One or more open circuit voltage limiters may be connected across the photovoltaic string or across selected groups of solar cells of the photovoltaic string. The limiter voltage may be greater than a maximum power point voltage but less than the open circuit voltage of the photovoltaic string.
    Type: Grant
    Filed: October 15, 2015
    Date of Patent: August 15, 2017
    Assignee: SunPower Corporation
    Inventors: Keith Johnston, Zachary S. Judkins
  • Patent number: 9710005
    Abstract: A photovoltaic (PV) system can include strings of PV collection devices. A positive parallel bus can be coupled to positive terminals of first and second strings and a negative parallel bus can be coupled to negative terminals of first and second strings.
    Type: Grant
    Filed: October 31, 2014
    Date of Patent: July 18, 2017
    Assignee: SunPower Corporation
    Inventors: Keith Johnston, Nicholas Ford
  • Patent number: 9685573
    Abstract: Arrangements of diodes and heat spreaders for solar modules are described. For example, a solar module may include a backsheet with a low profile, surface-mount diode disposed above the backsheet. A pair of ribbon interconnects is coupled to the low profile, surface-mount diode and may penetrate the backsheet.
    Type: Grant
    Filed: October 21, 2013
    Date of Patent: June 20, 2017
    Assignee: SUNPOWER CORPORATION
    Inventors: Keith Johnston, Ryan Linderman, Lewis Abra, Matthew Dawson
  • Patent number: 9671161
    Abstract: A gas liquefaction process, especially for producing LNG, maintains product flow rate and temperature by controlling the refrigeration so that variation to reduce any difference between actual and required product temperatures is initiated before variation of the product flow rate to reduce any difference between actual and required flow rates.
    Type: Grant
    Filed: December 8, 2011
    Date of Patent: June 6, 2017
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Michael Andrew Sicinski, Brian Keith Johnston, Scott Robert Trautmann, Mark Julian Roberts
  • Publication number: 20170025995
    Abstract: Devices for reducing the open circuit voltages of solar systems are described. In one embodiment, a solar system includes a string of a plurality of solar modules having an open circuit voltage. The solar system also includes a device for reducing the open circuit voltage of the string of the plurality of solar modules during an open circuit configuration.
    Type: Application
    Filed: October 7, 2016
    Publication date: January 26, 2017
    Inventors: Steven M. Kraft, Kevin Fischer, Greg Beardsworth, Zachary S. Judkins, Keith Johnston
  • Patent number: 9537036
    Abstract: Interconnects for optoelectronic devices are described. For example, an interconnect for an optoelectronic device includes an interconnect body having an inner surface, an outer surface, a first end, and a second end. A plurality of bond pads is coupled to the inner surface of the interconnect body, between the first and second ends. A stress relief feature is disposed in the interconnect body. The stress relief feature includes a slot disposed entirely within the interconnect body without extending through to the inner surface, without extending through to the outer surface, without extending through to the first end, and without extending through to the second end of the interconnect body.
    Type: Grant
    Filed: June 13, 2014
    Date of Patent: January 3, 2017
    Assignee: SunPower Corporation
    Inventors: Ryan Linderman, Keith Johnston, Thomas Phu, Matthew Dawson
  • Publication number: 20160365733
    Abstract: A photovoltaic system includes solar cells and an inverter configured to convert direct current generated by the solar cells to alternating current. The photovoltaic system includes a maximum power point (MPP) tracking module configured to perform MPP tracking for the photovoltaic system. The MPP tracking module is configured to detect shading of the solar cells and to modify its MPP tracking to prevent tracking of local MPPs. The MPP tracking module may be incorporated in the inverter.
    Type: Application
    Filed: June 14, 2016
    Publication date: December 15, 2016
    Applicant: SunPower Corporation
    Inventors: Zachary S. JUDKINS, Keith JOHNSTON
  • Patent number: 9472691
    Abstract: Devices for reducing the open circuit voltages of solar systems are described. In one embodiment, a solar system includes a string of a plurality of solar modules having an open circuit voltage. The solar system also includes a device for reducing the open circuit voltage of the string of the plurality of solar modules during an open circuit configuration.
    Type: Grant
    Filed: August 25, 2011
    Date of Patent: October 18, 2016
    Assignee: SunPower Corporation
    Inventors: Steven M. Kraft, Kevin Fischer, Greg Beardsworth, Zachary S. Judkins, Keith Johnston
  • Publication number: 20160284909
    Abstract: Solar cells can include a plurality of sub-cells that include a singulated and physically separated semiconductor portion such that adjacent ones of the singulated and physically separated semiconductor portions can have a groove therebetween. The solar cells can include a metallization structure that couples ones of the plurality of sub-cells. An interconnect structure can couple adjacent ones of the solar cells.
    Type: Application
    Filed: March 27, 2015
    Publication date: September 29, 2016
    Inventors: Gabriel Harley, Seung Bum Rim, Keith Johnston, Matthieu Minault Reich
  • Patent number: 9397611
    Abstract: A photovoltaic system includes solar cells and an inverter configured to convert direct current generated by the solar cells to alternating current. The photovoltaic system includes a maximum power point (MPP) tracking module configured to perform MPP tracking for the photovoltaic system. The MPP tracking module is configured to detect shading of the solar cells and to modify its MPP tracking to prevent tracking of local MPPs. The MPP tracking module may be incorporated in the inverter.
    Type: Grant
    Filed: March 27, 2012
    Date of Patent: July 19, 2016
    Assignee: SunPower Corporation
    Inventors: Zachary S. Judkins, Keith Johnston
  • Publication number: 20160102908
    Abstract: Described herein is a method of removing refrigerant from a natural gas liquefaction system in which vaporized mixed refrigerant is withdrawn from the closed-loop refrigeration circuit and introduced into a distillation column so as to be separated into an overhead vapor enriched in methane and a bottoms liquid enriched in heavier components. Overhead vapor is withdrawn from the distillation column to form a methane enriched stream that is removed from the liquefaction system, and bottoms liquid is reintroduced from the distillation column into the closed-loop refrigeration circuit. Also described are methods of altering the rate of production in a natural gas liquefaction system in which refrigerant is removed as described above, and a natural gas liquefaction systems in which such methods can be carried out.
    Type: Application
    Filed: October 10, 2014
    Publication date: April 14, 2016
    Applicant: AIR PRODUCTS AND CHEMICALS, INC.
    Inventors: Brian Keith Johnston, Gowri Krishnamurthy, Mark Julian Roberts
  • Publication number: 20160079914
    Abstract: A photovoltaic (PV) system is disclosed. The PV system can include a first and a second tracker that includes a first and a second plurality of PV collection devices. The PV system can include a first motor configured to adjust an angle of the first tracker. The PV system can include an inverter coupled to an output of the first plurality of PV collection devices. The inverter can include a first local controller comprising control circuitry configured to control the first motor. In an example, the inverter can be a string inverter. In one example, the inverter can a block inverter coupled to an output of the first and second plurality of PV collection devices. The PV system can also include a power collection unit, where the power collection unit can be coupled to the first plurality of PV collection devices and include the first local controller.
    Type: Application
    Filed: September 14, 2015
    Publication date: March 17, 2016
    Inventors: Junbo Wu, Keith Johnston, Chen-An Chen, Zachary S. Judkins
  • Publication number: 20160049791
    Abstract: A photovoltaic (PV) system can include strings of PV collection devices. A positive parallel bus can be coupled to positive terminals of first and second strings and a negative parallel bus can be coupled to negative terminals of first and second strings.
    Type: Application
    Filed: October 31, 2014
    Publication date: February 18, 2016
    Inventors: Keith Johnston, Nicholas Ford