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1.发明授权
公开(公告)号：US5194810A
公开(公告)日：1993-03-16
申请号：US813981
申请日：1991-12-26
IPC分类号： G01R33/383 , G01R33/3873 , H01F7/02
CPC分类号： G01R33/383 , G01R33/3873 , H01F7/0278
摘要： An open access superconducting MRI magnet includes a ferromagnetic frame open on at least two sides and having upper and lower end plates and at least two support posts. A superconducting coil assembly is mounted to each end plate for generating a magnetic flux field in a patient receiving area located between the end plates. A magnetic flux field shaping means is associated with each end plate. The flux field shaping means includes rose shims, inner rings mounted within the rose shims, and removable segments mounted to the rose shims. Transition plates are located between the support ports and end plates for minimizing flux leakage. In addition the end plates are formed with a varying thickness such that a cross section taken perpendicular to a return path of magnetic flux is substantially constant.
摘要翻译： 开放式超导MRI磁体包括在至少两个侧面上开放的铁磁框架，并且具有上端板和下端板以及至少两个支撑柱。 超导线圈组件安装到每个端板，用于在位于端板之间的患者接收区域中产生磁通场。 磁通量场成形装置与每个端板相关联。 通量场成形装置包括玫瑰垫片，安装在玫瑰垫片内的内圈和安装在玫瑰垫片上的可拆卸部分。 过渡板位于支撑端口和端板之间，以最小化漏磁。 此外，端板形成为具有变化的厚度，使得垂直于磁通的返回路径取得的横截面基本上是恒定的。
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公开(公告)号：US5412363A
公开(公告)日：1995-05-02
申请号：US259914
申请日：1994-06-10
IPC分类号： H01F7/02 , A61B5/055 , F25B9/14 , F25D19/00 , G01R33/38 , G01R33/3815 , H01F6/00 , H01F6/04 , H01F7/22 , G01V3/00
CPC分类号： G01R33/3806 , G01R33/3815 , H01F6/00 , H01F6/04 , F25B9/14 , F25D19/006 , Y10S505/893
摘要： An open access MRI magnet includes a ferromagnetic frame open on at least two sides and having upper and lower end plates and at least two support columns. A superconducting coil assembly is mounted to each end plate for generating a magnetic flux field in a patient receiving area located between the end plates. Each superconducting coil assembly includes a toroidal vacuum tight vessel, insulation, and one or more temperature shields mounted within the vacuum tight vessel. One or more coils of superconducting wire is wound within the vacuum vessel, and is coupled to a power source and to a persistent switch for maintaining a constant flow of current with no power consumption. A return path for the flux is provided by the end plates and support posts of the frame. The superconducting coils, the thermal shields, and the persistent switch are cooled by a cryocooler, by means of conduction through solid thermal conductors or by a combination of conduction and convection, through a fluid cooling circuit, without the consumption of a liquid cryogen.
摘要翻译： 开放式磁共振磁体包括在至少两个侧面上开放并具有上端板和下端板以及至少两个支撑柱的铁磁框架。 超导线圈组件安装到每个端板，用于在位于端板之间的患者接收区域中产生磁通场。 每个超导线圈组件包括环形真空密封容器，绝缘体和安装在真空密封容器内的一个或多个温度屏蔽件。 超导线的一个或多个线圈缠绕在真空容器内，并且耦合到电源和持久开关，用于在没有功率消耗的情况下保持恒定的电流流动。 用于焊剂的返回路径由框架的端板和支撑柱提供。 超导线圈，热屏蔽和持续开关由低温冷却器通过固体热导体传导或通过传导和对流的组合通过流体冷却回路冷却而不消耗液体冷冻剂。
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3.发明授权Open access superconducting MRI magnet having an apparatus for reducing magnetic hysteresis in superconducting MRI systems 失效具有用于降低超导MRI系统中磁滞的设备的开放式超导MRI磁体
公开(公告)号：US5414399A
公开(公告)日：1995-05-09
申请号：US812080
申请日：1991-12-19
IPC分类号： G01R33/385 , G01R33/3873 , H01F7/20 , G01R33/28
CPC分类号： G01R33/3806 , G01R33/385 , G01R33/3873
摘要： A MRI superconducting magnet having an open access frame with spaced parallel end plates, a superconducting coil assembly associated with each end plate, and gradient coils associated with each end plate includes an apparatus for minimizing hysteresis. The apparatus for minimizing hysteresis comprises a layer of nonferromagnetic conducting material interposed between the gradient coils and end plates. The interposed layer carries eddy currents induced by time varying magnetic fields produced by the gradient coils, thereby minimizing AC eddy current hysteresis from the end plates. The layer preferably has a thickness of at least one skin depth at the frequency associated with the time varying magnetic field. In another embodiment, each end plate has a plurality of slits formed therein for eliminating eddy currents in the end plates.
摘要翻译： MRI超导磁体具有带有间隔开的平行端板的开放式进入框架，与每个端板相关联的超导线圈组件以及与每个端板相关联的梯度线圈包括用于最小化滞后的装置。 用于最小化滞后的装置包括介于梯度线圈和端板之间的非铁磁导电材料层。 插入的层承载由梯度线圈产生的时变磁场引起的涡流，从而最小化来自端板的交流涡流滞后。 该层优选地具有与时变磁场相关联的频率处的至少一个皮肤深度的厚度。 在另一个实施例中，每个端板具有形成在其中的多个狭缝，用于消除端板中的涡流。
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公开(公告)号：US4980641A
公开(公告)日：1990-12-25
申请号：US393400
申请日：1989-08-11
IPC分类号： G01R33/38 , G01R33/383 , G01R33/385 , G01R33/421
CPC分类号： G01R33/421 , G01R33/3806 , G01R33/383 , G01R33/385
摘要： An apparatus for minimizing hysteresis in a magnetic resonance imaging device of the type utilizing a pair of oppositely charged parallel pole faces forming a magnetic field therebetween, and gradient coils spaced apart from each pole face for producing time varying magnetic fields, comprises a layer of nonferromagnetic conducting material interposed between the pole face and the gradient coil. The interposed layer carries eddy currents induced by time varying magnetic fields produced by the gradient coils, thereby minimizing AC induced eddy current hysteresis from the pole faces. The layer preferably has a thickness of at least one skin depth at the frequency associated with the time varying magnetic field. The layer is preferably contiguous with the pole face, and comprises copper or aluminum. In another embodiment, each pole face has a plurality of slits therethrough radiating inward from the circumference for eliminating the eddy currents in the pole face. The slits in one pole face are preferably symmetrical to those in the other. There are preferably twenty-four (24) slits spaced fifteen degrees (15.degree.) apart. There is also disclosed the method for accomplishing the same.
摘要翻译： 一种用于最小化磁共振成像装置中的磁滞的装置，该磁共振成像装置利用在它们之间形成磁场的一对相反电荷的平行极面以及与每个极面间隔开的用于产生时变磁场的梯度线圈，包括非铁磁层 介于极面和梯度线圈之间的导电材料。 插入层承载由梯度线圈产生的由时变磁场引起的涡流，从而最小化从极面引起的AC感应涡流滞后。 该层优选地具有与时变磁场相关联的频率处的至少一个皮肤深度的厚度。 该层优选与极面相邻，并且包括铜或铝。 在另一个实施例中，每个极面具有从圆周向内辐射的多个狭缝，以消除极面中的涡流。 一个极面中的狭缝优选地与另一个极面对应。 优选分开间隔十五度（15°）的二十四（24）个狭缝。 还公开了实现该方法的方法。
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公开(公告)号：US4990492A
公开(公告)日：1991-02-05
申请号：US293227
申请日：1989-01-03
申请人： Richard L. Creedon , Yen-Hwa L. Hsu
发明人： Richard L. Creedon , Yen-Hwa L. Hsu
CPC分类号： H01F6/06 , H01F41/048 , H01L39/143 , H01L39/248 , H01F2027/2819 , Y10S428/93 , Y10S505/701 , Y10S505/702 , Y10S505/703 , Y10S505/704 , Y10T29/49014 , Y10T428/31678
摘要： A method for manufacturing a stress controlled wire comprises the step of twisting superconductor fibers together into a bundle of fibers. A plurality of bundles are then twisted together and disposed within the lumen of a tube and the lumen is flooded with solder which is allowed to harden. The tube and its contents are subsequently heated as they are wound upon a drum to melt the solder and allow realignment of the superconductor fibers within the solder. The subsequent solidification of solder after the tube is wound onto the drum provides an unstressed support for the fiber bundles.
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6.发明授权
公开(公告)号：US4658229A
公开(公告)日：1987-04-14
申请号：US733232
申请日：1985-05-10
申请人： Wilkie Y. Chen , Yen-Hwa L. Hsu , John R. Purcell
发明人： Wilkie Y. Chen , Yen-Hwa L. Hsu , John R. Purcell
IPC分类号： G01R33/3815 , G01R33/3875 , H01F7/22
CPC分类号： G01R33/3815 , G01R33/3875 , Y10S505/879
摘要： A magnet system for providing a substantially homogeneous magnetic field in a region. The magnet system includes a main coil and a pair of correcting coils with the main coil generating a magnetic field in a zone including the region. The correcting coils are at first and second locations in the zone and are connected to one another so that a magnetic field generated by the main coil will induce currents in the correcting coils which oppose one another. The correcting coils are constructed so that there will be no resultant current in them when there is generated substantially the same field strength of both of the first and second locations. Thus, the generation of differing magnetic field strengths at the respective locations effects generation of a resultant current in the correcting coil causing strengthening of the magnetic field at the location having the lesser magnetic field strength and weakening of the magnetic field at the other location, making the net field relatively homogeneous.
摘要翻译： 一种用于在区域中提供基本均匀的磁场的磁体系统。 磁体系统包括主线圈和一对校正线圈，其中主线圈在包括该区域的区域中产生磁场。 校正线圈位于区域中的第一和第二位置处并且彼此连接，使得由主线圈产生的磁场将引起彼此相对的校正线圈中的电流。 校正线圈被构造成使得当第一位置和第二位置都产生基本上相同的场强时，在其中将不存在合成电流。 因此，在各个位置处产生不同的磁场强度会影响校正线圈中的合成电流的产生，从而在具有较小磁场强度的位置处增强磁场并使另一位置处的磁场变弱 净场相对均匀。
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