Abstract: An apparatus including a persistent current switch of a superconducting material which is electrically superconducting at a superconducting temperature and electrically resistive at a resistive mode temperature which is greater than the superconducting temperature. The apparatus further includes a first heat exchange element; a convective heat dissipation loop thermally coupling the persistent current switch to the first heat exchange element; a second heat exchange element spaced apart from the first heat exchange element; and a thermally conductive link thermally coupling the persistent current switch to the second heat exchange element. The first heat exchange element is disposed above the persistent current switch. The thermally conductive link may have a greater thermal conductivity at the superconducting temperature than at a second temperature which is greater than the superconducting temperature.

Abstract: A system including a first sealed housing with a first pressure and a second sealed housing with a second pressure. The first pressure is higher than the second pressure. The first sealed housing contains a predetermined gas and the second sealed housing contains a superconducting magnet. A sensor within the second housing monitors a voltage of parts of the magnet. When a processor determines a quenching event as a function of the monitored voltage, the processor actuates a valve that sealably connects the first and second housings. When the valve is in a first position, the first and second housings are sealed off from each other. When the valve is in a second position, the predetermined gas flows from the first housing into the second housing until a third pressure within the second housing is reached. The system can be used for protecting a cryo-free superconducting magnet.

Abstract: An apparatus including a persistent current switch of a superconducting material which is electrically superconducting at a superconducting temperature and electrically resistive at a resistive mode temperature which is greater than the superconducting temperature. The apparatus further includes a first heat exchange element; a convective heat dissipation loop thermally coupling the persistent current switch to the first heat exchange element; a second heat exchange element spaced apart from the first heat exchange element; and a thermally conductive link thermally coupling the persistent current switch to the second heat exchange element. The first heat exchange element is disposed above the persistent current switch. The thermally conductive link may have a greater thermal conductivity at the superconducting temperature than at a second temperature which is greater than the superconducting temperature.

Abstract: When testing or powering up a magnet in a magnetic resonance imaging device, a switch is provided that switches a winding between resistive and superconductive modes. The switch includes a housing that contains a winding wound about a bobbin, and an internal coolant cavity that contains coolant that cools the winding, A baffle separates the internal coolant cavity from an external coolant reservoir. The baffle has small apertures that permit influx of liquid coolant into the internal cavity to cool the winding, At high temperatures, the coolant in the internal cavity vaporizes causing the winding to further increase its temperature and resistance, Upon reduction of heat to the winding, the winding cools sufficiently to permit influx of liquid coolant, thereby restoring a superconductive mode of operation to the winding.

Abstract: When testing or powering up a magnet in a magnetic resonance imaging (MRI) device, a switch (10) is provided that switches a winding (12) between resistive and superconductive modes. The switch (10) comprises a housing (26) that contains a winding (12) wound about a bobbin (14), and an internal coolant cavity (16) that contains coolant that cools the winding (12). A baffle (20) separates the internal coolant cavity (16) from an external coolant reservoir (18). The baffle has small apertures that permit influx of liquid coolant into the internal cavity (16) to cool the winding. At high temperatures, the coolant in the internal cavity (16) vaporizes causing the winding to further increase its temperature and resistance. Upon reduction of heat to the winding (12), the winding cools sufficiently to permit influx of liquid coolant, thereby restoring a superconductive mode of operation to the winding (12).