Patents by Inventor Vishnu M. Sishtla

Vishnu M. Sishtla 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: 20230024289
    Abstract: A centrifugal compressor and a method of operating a centrifugal compressor. The centrifugal compressor includes: an impeller configured to suction a gas to be compressed; a diffuser disposed downstream of the impeller to pressurize the gas, the diffuser comprising a movable ring, a main passage in which the gas flows past the ring, and an openable branch passage; and a circulation loop comprising an inlet and an outlet, the outlet being in communication with an inlet of the impeller; the branch passage is disposed to be in communication with the main passage and the circulation loop when the ring moves into the main passage so that a portion of the gas in the main passage passes through the circulation loop and returns to the impeller so as to be suctioned, and to be closed when the ring is withdrawn from the main passage.
    Type: Application
    Filed: October 6, 2022
    Publication date: January 26, 2023
    Inventors: Lei Yu, Vishnu M. Sishtla, Sheng Chen
  • Patent number: 11555502
    Abstract: An illustrative example embodiment of a compressor includes an inlet defining an intake passage, a plurality of lateral inlet guide vanes in the intake passage, and a plurality of medial inlet guide vanes in the intake passage. The lateral guide vanes are selectively oriented to alter an amount of fluid flow through a first, lateral portion of the intake passage. The medial inlet guide vanes are selectively oriented to alter an amount of fluid flow through a second, medial portion of the intake passage.
    Type: Grant
    Filed: August 13, 2021
    Date of Patent: January 17, 2023
    Assignee: CARRIER CORPORATION
    Inventors: Vishnu M. Sishtla, Chaitanya Vishwajit Halbe
  • Patent number: 11499569
    Abstract: A compressor includes a housing. An impeller is located within the housing and rotatable about an impeller axis in a first rotational direction. A rotor section is rotatable about the impeller axis in a second rotational direction opposite the first rotational direction.
    Type: Grant
    Filed: June 16, 2020
    Date of Patent: November 15, 2022
    Inventors: Michael M. Joly, Chaitanya Vishwajit Halbe, William T. Cousins, Vishnu M. Sishtla
  • Patent number: 11499561
    Abstract: An example centrifugal compressor includes a housing that defines an inlet chamber and includes first and second openings that define a recirculation passage in fluid communication with the inlet chamber. An impeller is disposed within the housing and is rotatable about a longitudinal axis to draw fluid into the inlet chamber. The first and second openings are at different axial locations along the longitudinal axis. A plurality of inlet guide vanes are rotatable and situated in the inlet chamber. The centrifugal compressor includes a ring and a controller for moving the ring along the longitudinal axis between a first position and a second position when rotating the inlet guide vanes. The ring obstructs at least one of the first and second openings more in the second position than in the first position.
    Type: Grant
    Filed: September 23, 2021
    Date of Patent: November 15, 2022
    Assignee: Carrier Corporation
    Inventors: Vishnu M. Sishtla, William T. Cousins
  • Patent number: 11499767
    Abstract: A method of operating a heat exchanger system in which a compressor, which is drivable by a motor, is fluidly interposed between an evaporator and a condenser following receipt of a shutdown command is provided. The method includes positioning inlet guide vanes (IGVs) of the compressor in a first position in the event of at least one of a first precondition being in effect and the first and a second precondition both not being in effect. The method further includes positioning the IGVs in a second position in an event the first precondition is not in effect but the second precondition is in effect, ramping a speed of the compressor down until a third precondition takes effect, removing power from the motor and positioning the IGVs in the first position once power is removed from the motor.
    Type: Grant
    Filed: April 8, 2019
    Date of Patent: November 15, 2022
    Assignee: CARRIER CORPORATION
    Inventors: Vishnu M. Sishtla, Scott A. Nieforth
  • Patent number: 11493057
    Abstract: A centrifugal compressor and a method of operating a centrifugal compressor. The centrifugal compressor includes: an impeller configured to suction a gas to be compressed; a diffuser disposed downstream of the impeller to pressurize the gas, the diffuser comprising a movable ring, a main passage in which the gas flows past the ring, and an openable branch passage; and a circulation loop comprising an inlet and an outlet, the outlet being in communication with an inlet of the impeller; the branch passage is disposed to be in communication with the main passage and the circulation loop when the ring moves into the main passage so that a portion of the gas in the main passage passes through the circulation loop and returns to the impeller so as to be suctioned, and to be closed when the ring is withdrawn from the main passage.
    Type: Grant
    Filed: November 30, 2020
    Date of Patent: November 8, 2022
    Assignee: CARRIER CORPORATION
    Inventors: Lei Yu, Vishnu M. Sishtla, Sheng Chen
  • Patent number: 11421708
    Abstract: An impeller mountable within a centrifugal compressor includes a hub having a front side and a back side, the hub being rotatable about an axis of rotation and a plurality of vanes extending outwardly from the front side of the hub such that a plurality of passages is defined between adjacent vanes. The plurality of vanes is oriented such that a flow output from the plurality of passages adjacent the back side of the impeller is arranged at an angle to the axis of rotation of less than 20 degrees.
    Type: Grant
    Filed: January 9, 2019
    Date of Patent: August 23, 2022
    Assignee: CARRIER CORPORATION
    Inventors: William T. Cousins, Vishnu M. Sishtla, Michael M. Joly
  • Patent number: 11415148
    Abstract: A system is provided and includes a compressor. The compressor further includes a diffuser frame, a gas or oil actuator and a drive system. The diffuser frame defines a first channel through which compressed fluids are flowable, a second channel intersecting the first channel and a third channel extending from the second channel. The gas or oil actuator includes a piston and a head integrally coupled to the piston. The head and the piston are disposable in the second and third channels, respectively. The piston is movable in forward or reverse directions through the third channel such that the head is movable through the second channel and into or out of the first channel, respectively. The drive system is at least partially disposable in the third channel and configured to drive forward and rearward movements of the piston.
    Type: Grant
    Filed: April 9, 2019
    Date of Patent: August 16, 2022
    Assignee: CARRIER CORPORATION
    Inventors: Kai Deng, Vishnu M. Sishtla
  • Publication number: 20220255373
    Abstract: An electric compressor motor includes a stator ring having a plurality of stator winding slots and a plurality of stator windings. Each of said stator windings is received in a stator winding slot of the plurality of stator winding slots. The stator ring also includes a plurality of cooling slots. Each cooling slot in the plurality of coolant slots is defined along an axial length of at least one corresponding stator winding slot of the plurality of stator winding slots such that a shared opening between each stator winding slot and at least one corresponding coolant slot is defined. The cooling slots are configured to allow coolant to directly contact at least one stator winding in the corresponding at least one stator winding slot.
    Type: Application
    Filed: June 25, 2020
    Publication date: August 11, 2022
    Inventors: Vishnu M. Sishtla, Michael Westlake
  • Publication number: 20220228593
    Abstract: A refrigerant compressor assembly (20A, 20B, 20C) includes an axial compressor (22B, 22C, 22) that includes at least one axial stage. A downstream compressor (24) is located fluidly downstream of the axial compressor (22B, 22C, 22) and includes one of a mixed-flow impeller (46) or a centrifugal impeller (96). At least one motor (26, 27) is in driving engagement with at least one of the axial compressor (22B, 22C, 22) and the downstream compressor (24).
    Type: Application
    Filed: July 20, 2020
    Publication date: July 21, 2022
    Inventors: Michael M. Joly, Chaitanya Vishwajit Halbe, Vishnu M. Sishtla, William T. Cousins
  • Publication number: 20220186746
    Abstract: A compressor including a casing and an impeller arranged within the casing. The impeller is rotatable about an axis. A diffuser section is arranged within the casing. The diffuser section is positioned downstream from an outlet of the impeller and includes a first set of vanes disposed circumferentially about the diffuser section and a second set of vanes disposed circumferentially about the diffuser section. At least one vane in the second set of vanes includes an aspiration slot.
    Type: Application
    Filed: July 20, 2020
    Publication date: June 16, 2022
    Inventors: Michael M. Joly, Chaitanya Vishwajit Halbe, Vishnu M. Sishtla
  • Publication number: 20220186744
    Abstract: The present application discloses a diffuser system and a centrifugal compressor comprising the same. The diffuser system comprises: a passage through which a compressed gas is flowable; and a wall defining the passage, the wall comprising a movable part which is driven to enter the passage so as to change a flow area of the passage, wherein the movable part comprises an elastomer configured to expand to guide the flow of the compressed gas when at least a portion of the movable part enters the passage, and to retract when the movable part withdraws from the passage. The diffuser system involved in the present application re-orients a flow route of the compressed gas in the passage.
    Type: Application
    Filed: June 11, 2020
    Publication date: June 16, 2022
    Inventors: Hang Zhao, Vishnu M. Sishtla
  • Publication number: 20220186985
    Abstract: A coolant system includes a multistage compressor having a plurality of surge detection sensors. A condenser is connected to an outlet of the multistage compressor. An economizer is connected to an outlet of the condenser and has a gaseous coolant outlet and a liquid coolant outlet. The liquid coolant outlet is connected to a cooler and the gaseous coolant outlet is connected to a second or later stage of the multistage compressor via a controllable valve. A controller is communicatively coupled to the surge detection sensors and the controllable valve. The controller includes a non-transitory medium storing instructions for causing the controller to detect an occurrence of a surge and restricting a flow through the controllable valve until the surge has ceased.
    Type: Application
    Filed: June 29, 2020
    Publication date: June 16, 2022
    Inventors: Vishnu M. Sishtla, Lei Yu
  • Patent number: 11346366
    Abstract: A centrifugal compressor includes a shaft defining an axis, an impeller mounted to the shaft for rotation about the axis, and a diffuser section including a first wall, a second wall, and an opening defined between the first wall and the second wall. The opening of the diffuser section is arranged in fluid communication with the impeller. The first wall is rotatable about the axis and rotation of the first wall about the axis is mechanically driven.
    Type: Grant
    Filed: January 31, 2020
    Date of Patent: May 31, 2022
    Assignee: CARRIER CORPORATION
    Inventors: Michael M. Joly, Xiaodan Cai, Chaitanya V. Halbe, William T. Cousins, Vishnu M. Sishtla
  • Patent number: 11306950
    Abstract: A lubrication additive recovery system is provided for use with a vapor compression system. The vapor compression system includes a compressor having a bearing, a condenser and an evaporator. The lubrication additive recovery system includes a lubrication ring formed to define first and second through-holes, a first system by which a portion of a required supply of lubrication is drawn from the condenser and provided to the bearing through the first through-holes and a second system by which a remainder of the required supply of lubrication is recovered from the evaporator and provided along with compressor discharge gas to the bearing through the second through-holes.
    Type: Grant
    Filed: July 27, 2018
    Date of Patent: April 19, 2022
    Assignee: CARRIER CORPORATION
    Inventors: Vishnu M. Sishtla, Scott A. Nieforth
  • Patent number: 11293438
    Abstract: A screw compressor is provided including a casing having a suction port and a discharge port, a male rotor rotatable relative to the casing about a first axis, a female rotor rotatable relative to the casing about a second axis, and a magnetic gear system. The magnetic gear system includes a first magnetic gear associated with the male rotor and a second magnetic gear associated with the female rotor. The first magnetic gear and the second magnetic gear are positioned such that a magnetic field of the first magnetic gear interacts with the second magnetic gear to drive rotation of the female rotor about the second axis.
    Type: Grant
    Filed: December 13, 2017
    Date of Patent: April 5, 2022
    Assignee: CARRIER CORPORATION
    Inventors: Jagadeesh Tangudu, Vishnu M. Sishtla
  • Patent number: 11292987
    Abstract: A compressor system includes a compressor including a compressor inlet, a compressor outlet, and a bearing assembly, the compressor configured to compress a heat transfer fluid. An additive dispenser is fluidly coupled to the compressor upstream of the bearing assembly. The additive dispenser is configured to controllably release a volume of an additive material into the heat transfer fluid, the additive material configured to lubricate the bearing assembly. A method of lubricating a bearing assembly of compressor includes locating a volume of additive material at an additive dispenser fluidly coupled to a compressor, dispensing a portion of the additive material into the flow of heat transfer fluid at a selected time, flowing the heat transfer fluid containing the additive material to a bearing assembly of the compressor, and lubricating the bearing assembly of the compressor with the additive material.
    Type: Grant
    Filed: March 22, 2018
    Date of Patent: April 5, 2022
    Assignee: CARRIER CORPORATION
    Inventors: Zissis A. Dardas, Ulf J. Jonsson, Ying She, Zaffir A. Chaudhry, Vishnu M. Sishtla
  • Publication number: 20220049716
    Abstract: A mixed-flow compressor includes an impeller attached to a shaft and rotatable about a shaft axis. A vaneless diffuser is located axially downstream of the impeller and has a converging portion and a diverging portion. A vaned diffuser is located axially downstream of the vaneless diffuser.
    Type: Application
    Filed: June 16, 2020
    Publication date: February 17, 2022
    Inventors: Chaitanya Vishwajit Halbe, Michael M. Joly, William T. Cousins, Vishnu M. Sishtla
  • Publication number: 20220049717
    Abstract: A compressor includes a housing. An impeller is located within the housing and rotatable about an impeller axis in a first rotational direction. A rotor section is rotatable about the impeller axis in a second rotational direction opposite the first rotational direction.
    Type: Application
    Filed: June 16, 2020
    Publication date: February 17, 2022
    Inventors: Michael M. Joly, Chaitanya Vishwajit Halbe, William T. Cousins, Vishnu M. Sishtla
  • Patent number: 11231214
    Abstract: A heating, ventilation, air conditioning and refrigeration system includes a heat transfer fluid circulation loop configured to circulate a refrigerant therethrough, a purge gas outlet in operable communication with the heat transfer fluid circulation loop and at least one gas permeable membrane having a first side in operable communication with the purge gas outlet and a second side. The membrane includes a plurality of pores of a size to allow passage of contaminants through the membrane, while restricting passage of the refrigerant through the membrane, and further restricting passage of a vapor phase corrosion inhibitor through the membrane. A purge unit is in operable communication with the second side of the permeable membrane configured to receive a purge gas from the permeable membrane.
    Type: Grant
    Filed: January 30, 2019
    Date of Patent: January 25, 2022
    Assignee: CARRIER CORPORATION
    Inventors: Vishnu M. Sishtla, Zissis A. Dardas