Showing papers by "Evangelos Trifon Laskaris published in 2002"

Conduction cooled passively-shielded MRI magnet

Abstract: A magnetic resonance imaging (MRI) device for imaging a volume is provided with at least one main magnet for generating a magnetic field, and at least one gradient coil for manipulating the magnetic field generated by the at least one main magnet to image the volume. The magnetic fields generated by the at least one gradient coil are substantially unshielded.

Permanent magnet assembly and method of making thereof

Abstract: An imaging apparatus, such as an MRI system, contains at least one layer of soft magnetic material between the yoke and each permanent magnet. This imaging apparatus may be operated without pole pieces due to the presence of the soft magnetic material. The permanent magnets may be fabricated by magnetizing unmagnetized alloy bodies after the unmagnetized alloy bodies have been attached to the yoke.

Cryogenic cooling system for rotor having a high temperature super-conducting field winding

Abstract: A cooling fluid system is disclosed for providing cryogenic cooling fluid to a high temperature super-conducting rotor comprising: a re-circulation compressor; a storage tank having a second cryogenic fluid; an inlet line connecting the re-circulation compressor to the storage tank and to the rotor, and forming a passage for cooling fluid to pass from the re-circulation compressor through the storage tank and to the apparatus.

Cryogenic cooling system with cooldown and normal modes of operation

Abstract: A cryogenic cooling system (10) for use with a superconductive electric machine (12) includes a first set of components (14) arranged in a first circuit and adapted to force flow of a cryogen in the first circuit (16) to and from a superconductive electric machine (12) and being operable in a cooldown mode for cooling the cryogen and thereby the superconductive electric machine (12) to a normal operating temperature, and a second set of components (18) arranged in a second circuit and adapted to force flow of a cryogen in the second circuit (20) to and from the superconductive electric machine (12) and being operable in a normal mode for maintaining the cryogen and thereby the superconductive electric machine (12) at the normal operating temperature.

High temperature super-conducting synchronous rotor having an electromagnetic shield and method for assembly

Abstract: A rotor is disclosed for a synchronous machine comprising: a rotor core; a super-conducting coil winding extending around at least a portion of the rotor core, the coil winding having a pair of side sections on opposite sides of the rotor core; and a conductive shield around the rotor core and covering the coil winding.

High temperature super-conducting rotor coil support with split coil housing and assembly method

Abstract: A rotor is disclosed for a synchronous machine comprising: a rotor core; a super-conducting coil winding extending around at least a portion of the rotor, said coil winding having a side section adjacent a side of the rotor core; at least one tension rod extending through a conduit in said rotor core; and a housing attached to the tension rod and connected to the side section of the coil winding, wherein the housing comprises a pair of side panels.

Cold mass support structure and helium vessel of actively shielded high field open MRI magnets

Abstract: An open magnetic resonance imaging (MRI) device is provided with at least one main coil for generating a magnetic field for imaging a volume, and at least one shaping coil. The at least one shaping coil is positioned relative to the at least one main coil to shape the magnetic field in the volume.

Thermal shield suspension for superconductive magnets

Abstract: A method for assembling a thermal shield suspension assembly including a plurality of straps, wherein the straps are arranged in an alternately cross hatch arrangement such that a plurality of first straps extend at a first orientation with regards to the cryogenic vessel and a plurality of second straps extend at a second orientation with regards to the cryogenic vessel, and wherein the first orientation is different from the second orientation and each second strap is disposed between the adjacent first strap is provided, the method comprising securing the first strap including the tensioning block to a thermal shield flange and a cryogenic vessel flange and securing the second strap to the thermal shield flange and the cryogenic vessel flange.

High temperature superconducting rotor power leads

Abstract: The resistive power leads of a high temperature superconducting (HTS) rotor field coil are located in vacuum near the rotor axis and are cooled by thermal conduction to the return flow path (20) by bonding the leads to the tubing bulkhead (18) through ceramic insulators (22). The lead length, cross-section and electrical resistivity are optimized for minimum heat conduction and ohmic resistance heat transfer to the cold gas. Thermal expansion or contraction of the leads is accommodated by flexible sections at the warm and cold end of the leads.

Manufacturing equipment and method for coil

Abstract: PROBLEM TO BE SOLVED: To provide equipment and method for manufacturing superconductive field magnet winding in a rotor of a synchronous machine. SOLUTION: A racetrack shaped high temperature superconductive(HTS) coil is manufactured by winding, while drawing, on a precision coil mold, HTS tape (18) with bonding material such as insulation material for layers of pre-preg material filament ply so as to form a layer thereon. The coil mold comprises a racetrack shaped bobbin (12), two pieces of side boards (14), and a series of blocks (16) that configure the outside surface of the coil. The outside surface of the winding is joined to a heat-exchange tube and is enclosed with copper foil. The coil is heated within the mold so as to harden the epoxy resin and is removed from the coil mold. The coil structure thus obtained is a composite winding body with strength made in dimensions within a precision tolerance.

A rotor with a super-conducting coil support and a method for supporting a super-conducting rotor coil

Abstract: A rotor having a superconducting coil winding (34) is disclosed having a rotor core (22) having at least one conduit (46) extending through the core; at least one tension rod (42) extending between the pair of side sections of the coil winding and through said at least one conduit of the rotor; and an insulator (52) in the conduit thermally separating the tension rod from the rotor.

Method and apparatus for manufacturing a high temperature superconducting coil

Abstract: A racetrack shaped high temperature superconducting (HTS) coil is fabricated by layer winding HTS tape (18) under tension on a precision coil form with a binder such as pre-preg filament-ply interlayer insulation. The coil form includes a racetrack shaped bobbin (12), two side plates (14) and a series of blocks (16) that define the outside surface of the coil. The outside surface of the winding is over-wrapped with a copper foil bonded to heat exchanger tubing. The coil is baked in the coil form to cure the epoxy then released from the coil form. The resulting coil structure is a strong winding composite built to close tolerance dimensions.

Cryogenic cooling and refrigeration system and method

Abstract: PROBLEM TO BE SOLVED: To provide a cooling fluid system 50 or method capable of commer cially supplying cryogenic cooling fluid to a high temperature superconductive machinery with high reliability and economical efficiency. SOLUTION: This system comprises a recirculation compressor, a storage tank having a second cryogenic fluid, and an inlet line for connecting the recirculation compressor to the storage tank and a rotor to form a passage for a first cryogenic cooling fluid advanced from the recirculation compressor to a device through the storage tank. The used first cooling fluid is returned to the recirculation compressor again from the rotor through a countercurrent heat exchanger (here, the heat from the compressed first cooling fluid, advancing to the rotor is conducted to the used first cooling gas). COPYRIGHT: (C)2003,JPO

Cryogenic refrigeration system and method having an open-loop short-term cooling system for a superconducting field winding

Abstract: A cooling fluid system (50) is disclosed for providing cryogenic cooling fluid to a high temperature super-conducting machine (10), wherein said system includes a main cooling system (52) and a second cooling system (54) said second cooling system comprising a storage device (74) having a first cryogenic fluid (70); at least one cooling coupling (82) in fluid communication with the first cryogenic fluid from the storage device and a second cryogenic fluid flowing through the main cooling system.

High Temperature Superconducting Synchronous Rotor Coil Support with Tension Rods

Abstract: of EP1261116A rotor for a synchronous machine is disclosed comprising: a rotor; a super-conducting coil winding (34) extending around at least a portion of the rotor, said coil winding having a pair of side sections on opposite sides of said rotor; at least one tension rod (42) extending between the pair of side sections (40) of the coil winding and through conduits (46) in said rotor; and a coil housing (44) at each of opposite ends of said tension rod, wherein said coil housing wraps around said coil winding and is attached to said tension rod.