Patents Assigned to R & D Dynamics Corporation
  • Patent number: 6997686
    Abstract: A two-stage compressor for generating necessary pressure differential for air-conditioning applications with air-cooled, water-cooled and evaporative-cooled condensing systems using low-pressure refrigerant, such as R134a, is provided. A rotating assembly is mounted for rotation in a compressor housing and includes a shaft, a thrust bearing disk associated with the shaft to maintain an axial position of the rotating assembly, a motor rotor mounted on the shaft, and first and second impellers mounted for rotation with the shaft. First and second journal bearings are mounted in the compressor housing to support the shaft and maintain radial positioning of the rotating assembly. Volute housings including a spiral-shaped volute are associated with each of the impellers to collect and further discharge gas compressed by the impellers. Diffusers having air-foil shaped vanes are locate in the volute channels adjacent the discharge outlets of the impellers to aide in the discharge of gas from the impellers.
    Type: Grant
    Filed: December 19, 2003
    Date of Patent: February 14, 2006
    Assignee: R & D Dynamics Corporation
    Inventors: Giridhari L. Agrawal, Niels A. Jorgensen
  • Patent number: 6948853
    Abstract: A stacked foil thrust bearing assembly provides a compact, lightweight, high load capacity, high temperature, oil-free foil thrust bearing for use in high speed rotating machinery. A stacked foil thrust bearing assembly comprises a plurality of thrust runners in adjacently spaced and parallel relationship. Each thrust runner includes an annular-shaped portion having generally opposite axial sides, and a thrust bearing positioned on each of the generally opposite axial sides. Each thrust bearing includes a thrust bearing plate and a spring plate operatively engaging the thrust bearing plate. A plurality of foils are circumaxially dispersed about one axial side of the thrust bearing plates. A plurality of springs are circumaxially dispersed about one axial side of the spring bearing plates.
    Type: Grant
    Filed: June 27, 2003
    Date of Patent: September 27, 2005
    Assignee: R & D Dynamics Corporation
    Inventor: Giridhari L. Agrawal
  • Publication number: 20050189720
    Abstract: An improved and enhanced dynamic seal for use in high-speed turbomachinery includes an inner ring coupled to an outer sleeve. The coupling between the inner ring and the outer sleeve is strengthened by forming an increased surface area, exhibited by recesses, in at least one of the outer surface of the inner ring and the inner surface of the outer sleeve, and by providing an adhesive material in the recesses to bond the inner ring to the outer sleeve.
    Type: Application
    Filed: February 24, 2005
    Publication date: September 1, 2005
    Applicant: R & D Dynamics Corporation
    Inventor: Giridhari Agrawal
  • Publication number: 20050185865
    Abstract: An improved and enhanced hydrodynamic fluid film bearing for rotatably supporting a shaft journal is provided and includes a stationary retaining member, at least two generally cylindrical foil elements attached to one another and forming an anti-rotation fin, and a generally cylindrical resilient backing member. The retaining member has an inner surface defining a cylindrical opening for receiving a shaft journal. The inner surface also includes a longitudinally extending slot in which the anti-rotation fin formed by the foil elements is mounted so that the foil elements line at least a portion of the cylindrical opening. The resilient member is also disposed within the cylindrical opening generally concentric to and radially outward from the foil elements. The foil elements may be discrete elements attached together to form the anti-rotation fin, or alternatively formed from a single foil with a bend defining the anti-rotation fin.
    Type: Application
    Filed: February 19, 2004
    Publication date: August 25, 2005
    Applicant: R & D Dynamics Corporation
    Inventor: Giridhari Agrawal
  • Publication number: 20050147335
    Abstract: A stacked foil thrust bearing assembly provides a compact, lightweight, high load capacity, high temperature, oil-free foil thrust bearing for use in high speed rotating machinery. A stacked foil thrust bearing assembly comprises a plurality of thrust runners in adjacently spaced and parallel relationship. Each thrust runner includes an annular-shaped portion having generally opposite axial sides, and a thrust bearing positioned on each of the generally opposite axial sides. Each thrust bearing includes a thrust bearing plate and a spring plate operatively engaging the thrust bearing plate. A plurality of foils are circumaxially dispersed about one axial side of the thrust bearing plates. A plurality of springs are circumaxially dispersed about one axial side of the spring bearing plates.
    Type: Application
    Filed: June 27, 2003
    Publication date: July 7, 2005
    Applicant: R & D Dynamics Corporation
    Inventor: Giridhari Agrawal
  • Publication number: 20040179947
    Abstract: A two-stage compressor for generating necessary pressure differential for air-conditioning applications with air-cooled, water-cooled and evaporative-cooled condensing systems using low-pressure refrigerant, such as R134a, is provided. A rotating assembly is mounted for rotation in a compressor housing and includes a shaft, a thrust bearing disk associated with the shaft to maintain an axial position of the rotating assembly, a motor rotor mounted on the shaft, and first and second impellers mounted for rotation with the shaft. First and second journal bearings are mounted in the compressor housing to support the shaft and maintain radial positioning of the rotating assembly. Volute housings including a spiral-shaped volute are associated with each of the impellers to collect and further discharge gas compressed by the impellers. Diffusers having air-foil shaped vanes are locate in the volute channels adjacent the discharge outlets of the impellers to aide in the discharge of gas from the impellers.
    Type: Application
    Filed: December 19, 2003
    Publication date: September 16, 2004
    Applicant: R & D Dynamics Corporation
    Inventors: Giridhari L. Agrawal, Niels A. Jorgensen
  • Publication number: 20040066991
    Abstract: The present invention provides a compliant foil thrust bearing that will remain parallel and compliant to a thrust runner operatively coupled to a rotating shaft of high speed rotating machinery over a broad range of size and operating environments and loads. The thrust bearing comprises a thrust bearing plate including a plurality of decoupled bearing segments, and a spring plate operatively engaging the thrust bearing plate, the spring plate including a plurality of decoupled spring plate segments. The respective decoupled segments are defined in part by a plurality of line of weakness, such as slits, slots, perforations, etched lines and grooves, circumaxially dispersed about the thrust bearing plate and the spring plate. A plurality of compliant foils are disposed on the surface of the thrust bearing plate, and a plurality of springs are disposed on the surface of the spring plate to improve the compliancy of the thrust bearing.
    Type: Application
    Filed: June 27, 2003
    Publication date: April 8, 2004
    Applicant: R & D Dynamics Corporation
    Inventor: Giridhari L. Agrawal
  • Publication number: 20040005228
    Abstract: This invention provides a small, high efficiency, oil free motor driven compressor/blower suitable for providing pressurized, contamination-free gas and or air to transportation, industrial and aerospace fuel cell systems or other contaminant-intolerant applications. The motor driven compressor/blower rotor assembly is supported by foil air bearings and rotates at high speed by using a high frequency drive. The impeller is a centrifugal type design. The MDC can be easily integrated into the air management system of a fuel cell.
    Type: Application
    Filed: July 2, 2003
    Publication date: January 8, 2004
    Applicant: R & D Dynamics Corporation
    Inventors: Giridhari L. Agrawal, Charles W. Buckley
  • Patent number: 5634723
    Abstract: A hydrodynamic fluid film bearing has a stationary retaining member (12) having a cylindrical opening (14) to receive for rotation therein a rotatable shaft (16). The inner surface (20) of the opening (14) is lined by a generally cylindrical-shaped foil assembly (18) comprised of a plurality of foil sub-assemblies (24) each comprised of spring foils (26), contact foils (30) and, optionally, inner foils (32). Each foil sub-assembly (24) subtends a rotational segment, less than all, of the inner surface (20), e.g., from about 45 degrees to 120 degrees of rotation. The spring foils (26) and contact foils (30) are affixed to the retaining member (12) in such a way that sliding travel of the spring foils (26) along the inner surface (20) is in the opposite rotational direction of sliding travel of the contact foils (30) along the inner surface (20). The foil sub-assemblies (24) may be affixed to the retaining member (12) by means of keyways (22a-22e) within which the foil sub-assemblies (24) are mounted.
    Type: Grant
    Filed: April 17, 1996
    Date of Patent: June 3, 1997
    Assignee: R & D Dynamics Corporation
    Inventor: Giridhari L. Agrawal