# US 8,148,987 B2 · Magnetic resonance device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,148,987 B2 - Document ID: US8148987B2 - Status: Granted - Kind: B2 - Application number: 12/718,328 - Filed: 2010-03-05 - Published: 2010-09-09 - Granted: 2012-04-03 - Earliest claimed: 2009-03-06 - Assignees: Siemens Aktiengesellschaft - Inventors: Marcel Jan Marie Kruip - Web page: https://patentgrep.com/patent/US8148987B2 ## CPC - G01R 33/3854: {means for active and/or passive vibration damping or acoustical noise suppression in gradient magnet coil systems} - G01R 33/3858: {Manufacture and installation of gradient coils, means for providing mechanical support to parts of the gradient-coil assembly (manufacture of inductances or coils in general H01F41/00)} - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) ## Abstract A magnetic resonance device has a cryostat and a gradient coil assembly situated within an inner bore of the cryostat. A seal is positioned between the gradient coil assembly and the inner bore. The seal includes a first fluid filled toroid or helix mounted concentrically with the gradient coils; and a second fluid filled toroid or helix situated within the first toroid, or first helix. ## Claims ### Claim 1 A magnetic resonance apparatus comprising: a cryostat having an inner bore extending therethrough; a gradient coil assembly located within said inner bore of the cryostat; a seal between said gradient coil assembly and said inner bore; and said seal comprising: a first toroid mounted concentrically with respect to said gradient coil assembly and defining a first interior volume filled with a first fluid, and a second toroid defining a second interior volume filled with a second fluid, wherein said second toroid is disposed within said first fluid filling said first interior volume of said first toroid, and wherein said first toroid and said second toroid are substantially concentric. ### Claim 2 (depends on 1) An apparatus as claimed in claim 1 wherein said gradient coil assembly has opposite ends, and wherein said seal is a first seal located at a first of said opposite ends of said gradient coil assembly, and wherein said apparatus comprises a second seal comprising: a third toroid mounted concentrically with respect to said gradient coil assembly and defining a third interior volume filled with said first fluid, and a fourth toroid defining a fourth interior volume filled with said second fluid, wherein said fourth toroid is disposed within said first fluid filling said third interior volume of said third toroid, and wherein said third toroid and said fourth toroid are substantially concentric, said second seal being located at a second of said opposite ends of said gradient coil assembly. ### Claim 3 (depends on 2) An apparatus as claimed in claim 2 wherein said first and second seals have a space therebetween, and wherein said space is evacuated. ### Claim 4 (depends on 1) An apparatus as claimed in claim 1 wherein said first fluid is a liquid, and wherein said second fluid is a gas. ### Claim 5 (depends on 4) An apparatus as claimed in claim 4 wherein said gas in said second toroid is at a higher pressure than the liquid in said first toroid. ### Claim 6 (depends on 4) An apparatus as claimed in claim 4 comprising a cooling circuit, and wherein said cooling circuit cools said liquid in said first toroid. ### Claim 7 (depends on 4) An apparatus as claimed in claim 4 wherein said gas is selected from the group consisting of air, argon and nitrogen. ### Claim 8 (depends on 1) An apparatus as claimed in claim 1 wherein said first fluid is a gas and wherein said second fluid is a liquid. ### Claim 9 (depends on 1) An apparatus as claimed in claim 1 wherein said first toroid comprises a layflat hose. ### Claim 10 (depends on 1) An apparatus as claimed in claim 1 comprising a plurality of further seals situated around said gradient coil assembly. ### Claim 11 (depends on 10) An apparatus as claimed in claim 10 wherein each of said further seals comprises a fluid-filled toroid. ### Claim 12 (depends on 10) An apparatus as claimed in claim 10 wherein said plurality of further seals are respectively substantially equally spaced along a length of said gradient coil assembly. ### Claim 13 (depends on 10) An apparatus as claimed in claim 10 wherein each of said plurality of further seals is saddle-shaped. ### Claim 14 (depends on 10) An apparatus as claimed in claim 10 wherein each of said seal and said plurality of further seals has a pressure and a spring constant that is adjusted to set an orientation of said gradient coil assembly within said inner bore. ### Claim 15 (depends on 10) An apparatus as claimed in claim 10 wherein said gradient coil assembly comprises a resin former and gradient coils embedded therein, and wherein said former has a plurality of grooves therein in which said seal and said further seals are respectively seated. ### Claim 16 (depends on 1) An apparatus as claimed in claim 1 wherein said gradient coil assembly comprises a resin former and gradient coils embedded therein, said resin former having a groove therein in which said seal is seated. ### Claim 17 A magnetic resonance apparatus comprising: a cryostat having an inner bore extending therethrough; a gradient coil assembly situated within said inner bore of said cryostat; a seal between said gradient coil assembly and said inner bore; and said seal comprising: a first helix mounted concentrically with respect to said gradient coil assembly and defining a first interior volume filled with a first fluid, and a second helix defining a second interior volume filled with a second fluid, wherein said second helix is disposed within said first fluid filling said first interior volume of said first helix, and wherein each turn of said first helix is substantially concentric with a corresponding turn of said second helix. ### Claim 18 (depends on 17) An apparatus as claimed in claim 17 wherein said first fluid is a liquid and wherein said second fluid is a gas. ### Claim 19 (depends on 18) An apparatus as claimed in claim 18 comprising a cooling circuit in communication with said liquid in said first helix to cool said liquid. ### Claim 20 (depends on 1) An apparatus as claimed in claim 1, wherein the gradient coil assembly and the inner bore are cylindrical.