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: 20200040942
    Abstract: A bearing (20; 150; 152) comprises: an inner race (26); an outer race (28); and a plurality of rolling elements (30). The inner race comprises a nitrogen-alloyed steel (40). The outer race comprises a steel (42) with lower nitrogen content than said nitrogen-alloyed steel.
    Type: Application
    Filed: August 31, 2017
    Publication date: February 6, 2020
    Applicant: Carrier Corporation
    Inventors: Vishnu M. Sishtla, Ulf J. Jonsson, Zaffir A. Chaudhry
  • Patent number: 10544801
    Abstract: A compressor system having a centrifugal compressor, controller and an interface is disclosed. The compressor includes adjustable guide vanes and a variable geometry diffuser. The controller is in electrical communication with each of the guide vanes and diffuser so as to monitor and adjust positions thereof in accordance with a predetermined control algorithm. The control algorithm is implemented in accordance with a method of controlling the centrifugal compressor. The method adjusts the position of the diffuser based on the actual lift, guide vane position and predetermined relationships between diffuser position and reference lift.
    Type: Grant
    Filed: October 19, 2010
    Date of Patent: January 28, 2020
    Assignee: CARRIER CORPORATION
    Inventors: Vishnu M. Sishtla, Joost Brasz
  • Patent number: 10539352
    Abstract: A compressor (22) has a housing assembly (40) with a suction port (24), a discharge port (26), and a motor compartment (60). An electric motor (42) has a stator (62) within the motor compartment and a rotor (64) within the stator. The rotor is mounted for rotation about a rotor axis (500). One or more working impellers (44) are coupled to the rotor to be driven by the rotor in at least a first condition so as to draw fluid in through the suction port and discharge the fluid from the discharge port. An inlet guide vane (IGV) array (174) is between the suction port (24) and the one or more impellers (44). One or more bearings (66, 68) support the rotor (64) and/or the one or more impellers (44). A purge unit (400) has a vapor inlet line (410) for receiving a refrigerant flow and a return line (414, 417A, 417B) for returning a contaminant-depleted refrigerant flow. A supply flowpath (407A, 407B) for supplying refrigerant to the bearings extends from the purge unit.
    Type: Grant
    Filed: April 15, 2014
    Date of Patent: January 21, 2020
    Assignee: Carrier Corporation
    Inventors: Ulf J. Jonsson, Vishnu M. Sishtla, Zaffir A. Chaudhry
  • Publication number: 20200011337
    Abstract: An impeller of a centrifugal compressor comprising an impeller body (54) rotatable about an impeller axis Wand a motor operable to drive said impeller about said impeller axis. The motor includes a stator assembly (72) and a rotor assembly (76). The rotor assembly is associated with said impeller body.
    Type: Application
    Filed: December 13, 2017
    Publication date: January 9, 2020
    Inventors: Jagadeesh Tangudu, Vishnu M. Sishtla
  • Patent number: 10527050
    Abstract: In one embodiment, a compressor assembly is provided. The compressor assembly includes a compressor having an inlet, an outlet, and at least one bearing, the compressor configured to compress a first refrigerant. The assembly further includes a lubrication supply conduit fluidly coupled to the compressor and configured to supply a lubricant to the at least one bearing. The lubricant is a second refrigerant.
    Type: Grant
    Filed: March 17, 2015
    Date of Patent: January 7, 2020
    Assignee: CARRIER CORPORATION
    Inventor: Vishnu M. Sishtla
  • Patent number: 10480831
    Abstract: A vapor compression system (20) comprises a compressor (22) having one or more bearing systems (66, 68) supporting a rotor and/or one or more working elements (44). One or more bearing feed passages (114) are coupled to the bearings to pass fluid along a supply flowpath to the bearings. A mechanical pump (130; 330) is positioned to drive fluid along the supply flowpath. An ejector (140, 150) has a motive flow inlet (142, 152) coupled to the mechanical pump to receive refrigerant from the mechanical pump.
    Type: Grant
    Filed: January 27, 2014
    Date of Patent: November 19, 2019
    Assignee: Carrier Corporation
    Inventors: Ulf J. Jonsson, Vishnu M. Sishtla, Zaffir A. Chaudhry
  • Publication number: 20190323515
    Abstract: A compressor (22) comprises: a housing (50); a shaft (70); a plurality of bearings (66, 67, 68, 74, 76) mounting the shaft to the housing for relative rotation about an axis (500); and a motor (52). The motor has: a rotor (64) mounted on the shaft; and a stator (62). A first impeller (54A) is mounted the shaft to a first side of the motor. A second impeller (54B) is mounted the shaft to a second side of the motor. The first impeller is an open impeller and the second impeller is a shrouded impeller.
    Type: Application
    Filed: November 9, 2017
    Publication date: October 24, 2019
    Applicant: Carrier Corporation
    Inventor: Vishnu M. Sishtla
  • Publication number: 20190285081
    Abstract: A centrifugal compressor impeller (60; 160) has a hub (62; 162) having a gaspath surface (64; 164) extending from a leading end to a trailing end. A plurality of blades (70A, 70B; 170) extend from the hub gaspath surface and each have: a leading edge (72A, 72B; 172); a trailing edge (74A, 74B; 174); a first face (80A, 80B; 180); a second face (82A, 82B; 182); and a tip (78A, 78B; 178). A plurality of flow splitter segments (120, 122; 320, 322) extend between associated twos of the blades and each spaced from both the hub gaspath surface and the tips of the associated two blades.
    Type: Application
    Filed: February 20, 2019
    Publication date: September 19, 2019
    Applicant: Carrier Corporation
    Inventors: Vishnu M. Sishtla, William T. Cousins
  • Publication number: 20190285085
    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: Application
    Filed: January 9, 2019
    Publication date: September 19, 2019
    Inventors: William T. Cousins, Vishnu M. Sishtla, Michael M. Joly
  • Publication number: 20190271491
    Abstract: A vapor compression system (20, 400, 420, 440, 460, 480) has: a compressor (22) having a suction port (40) and a discharge port (42); a heat rejection heat exchanger (58) coupled to the discharge port to receive compressed refrigerant; a heat absorption heat exchanger (88); a first lubricant flowpath (120, 126; 120) from the heat rejection heat exchanger to the compressor; a second lubricant flowpath (121, 126; 121) from the heat absorption heat exchanger to the compressor; at least one lubricant pump (190; 190, 191); at least one liquid level sensor (180, 181; 180, 181, 330); and a controller (900) configured to control lubricant flow along the first lubricant flowpath and the second lubricant flowpath based output based on output of the at least one liquid level sensor.
    Type: Application
    Filed: August 9, 2017
    Publication date: September 5, 2019
    Applicant: Carrier Corporation
    Inventors: Vishnu M. Sishtla, Scott A. Nieforth
  • Publication number: 20190249681
    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: Application
    Filed: February 11, 2019
    Publication date: August 15, 2019
    Inventors: Vishnu M. Sishtla, William T. Cousins
  • Publication number: 20190249687
    Abstract: A diffuser for a centrifugal compressor and a centrifugal compressor having the same. The diffuser (100) comprises a drive component (110), a transmission assembly (120), an adjustment assembly (130), a spool valve assembly (140) and a rear wall (150); wherein the transmission assembly is used for transmitting power produced by the drive component to the adjustment assembly, the adjustment assembly is capable of circumferentially reciprocating with respect to the rear wall and driving the spool valve assembly to reciprocate axially; and wherein a rolling element (160) is provided between the adjustment assembly and the rear wall. Intervention of a mechanism for adjusting a flow passage width is better achieved by such an arrangement in combination with an existing configuration of the diffuser; and a low-friction fit between the adjustment assembly and the rear wall is achieved by the rolling element.
    Type: Application
    Filed: October 23, 2017
    Publication date: August 15, 2019
    Inventors: Vishnu M. Sishtla, Kai Deng, Zhanbo Du, Xili Liu, Scott A. Nieforth, Biao Shu, Danni Yuan
  • Publication number: 20190242631
    Abstract: System includes a compressor having a compressor suction port and a compressor discharge port; a heat rejection heat exchanger fluidly coupled to the compressor discharge port; an expansion device fluidly coupled to an outlet of the heat rejection heat exchanger; a heat absorption heat exchanger fluidly coupled to the expansion device; a hot gas bypass line fluidly coupled to the compressor discharge port; an ejector comprising a motive port fluidly coupled to the hot gas bypass line, a suction port fluidly coupled to an outlet of the heat absorption heat exchanger and a discharge port fluidly coupled to the compressor suction port; a hot gas bypass valve positioned between the compressor discharge port and the motive port of the ejector; a flow control valve fluidly coupled to the outlet of the heat absorption heat exchanger, and fluidly coupled to the suction port of the ejector and the compressor suction port.
    Type: Application
    Filed: February 6, 2019
    Publication date: August 8, 2019
    Inventors: Vishnu M. Sishtla, William T. Cousins
  • Publication number: 20190242408
    Abstract: A compressor includes a diffuser section having a diffuser structure and a silencer. The silencer includes a silencer housing defining a cavity and a silencing pad disposed within the cavity, wherein an exposed surface of the silencing pad is arranged in contact with a portion of the diffuser structure.
    Type: Application
    Filed: January 14, 2019
    Publication date: August 8, 2019
    Inventor: Vishnu M. Sishtla
  • Publication number: 20190234661
    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: Application
    Filed: January 30, 2019
    Publication date: August 1, 2019
    Inventors: Vishnu M. Sishtla, Zissis A. Dardas
  • Publication number: 20190234216
    Abstract: A balancing weight mountable within a balance hole of a rotary component includes a cylindrical body having a desired weight. An opening is formed in a portion of the body to define a hollow passageway and a mechanism couples the cylindrical body within an interior of the balance hole.
    Type: Application
    Filed: December 11, 2018
    Publication date: August 1, 2019
    Inventors: Vishnu M. Sishtla, Jing Chen
  • Patent number: 10364826
    Abstract: An inlet guide vane assembly (60) is provided including a plurality of vane subassemblies (62) configured to rotate relative to a blade ring housing (64) to control a volume of air flowing there through. The inlet guide vane assembly (60) also includes a plurality of drive mechanisms (80). Each drive mechanism (80) is operably coupled to one of the plurality of vane subassemblies (62). The vane subassemblies (62) may be rotated independently.
    Type: Grant
    Filed: February 20, 2014
    Date of Patent: July 30, 2019
    Assignee: CARRIER CORPORATION
    Inventor: Vishnu M. Sishtla
  • Publication number: 20190178537
    Abstract: A vapor compression system (20; 400; 420) comprises: a compressor (22) having a suction port (40) and a discharge port (42); a heat rejection heat exchanger (58) coupled to the discharge port to receive compressed refrigerant; a heat absorption heat exchanger (88); a first lubricant flowpath (120, 126) from the heat rejection heat exchanger to the compressor; a second lubricant flowpath (121, 126) from the heat absorption heat exchanger to the compressor; at least one lubricant pump (190); and a controller (900) configured to control lubricant flow along the first lubricant flowpath and the second lubricant flowpath based on a sensed fluctuation.
    Type: Application
    Filed: August 10, 2017
    Publication date: June 13, 2019
    Applicant: Carrier Corporation
    Inventors: Scott A. Nieforth, Vishnu M. Sishtla
  • Patent number: 10267539
    Abstract: A vapor compression system comprising a centrifugal compressor (22) having: an inlet (24); an outlet (26); a first impeller stage (28); a second impeller stage (30); and a motor (34) coupled to the first impeller stage and second impeller stage. A first heat exchanger (38) is downstream of the outlet along a refrigerant flowpath. An expansion device (56) and a second heat exchanger (64) are upstream of the inlet along the refrigerant flowpath. A bypass flowpath (120; 320) is positioned to deliver refrigerant from the compressor bypassing the first heat exchanger. A valve (128) is positioned to control flow through the bypass flowpath, wherein: the bypass flowpath extends from a first location (140) intermediate the inlet and outlet to a second location (142; 342) downstream of the first heat exchanger along the refrigerant flowpath.
    Type: Grant
    Filed: January 20, 2015
    Date of Patent: April 23, 2019
    Assignee: Carrier Corporation
    Inventor: Vishnu M. Sishtla
  • Patent number: 10228168
    Abstract: A compressor (22) has a housing assembly (40) with a suction port (24), a discharge port (26), and a motor compartment (60). An electric motor (42) has a stator (62) within the motor compartment and a rotor (64) within the stator. The rotor is mounted for rotation about a rotor axis (500). One or more working impellers (44) are coupled to the rotor to be driven by the rotor in at least a first condition so as to draw fluid in through the suction port and discharge the fluid from the discharge port. An inlet guide vane (IGV) array (174) is between the suction port (24) and the one or more impellers (44). One or more bearing systems (66, 68) support the rotor (64) and/or the one or more impellers (44). One or more main drain passages (120, 234 206; 120, 232, 202, 206) are coupled to the bearings to pass fluid along a drain flowpath from the bearings to a location (172) upstream of the impeller and downstream of the IGV array.
    Type: Grant
    Filed: February 19, 2014
    Date of Patent: March 12, 2019
    Assignee: Carrier Corporation
    Inventors: Ulf J. Jonsson, Vishnu M. Sishtla, Zaffir A. Chaudhry