公开(公告)号：US5851416A

公开(公告)日：1998-12-22

申请号：US798111

申请日：1997-02-12

申请人： Kuldip Raj ,  Ronald E. Rosensweig ,  Lutful M. Aziz

发明人： Kuldip Raj ,  Ronald E. Rosensweig ,  Lutful M. Aziz

IPC分类号： H01F1/34 ,  H01F1/44

CPC分类号： H01F1/44

摘要： A ferrofluid composition comprising a colloidal dispersion of finely divided magnetic particles in a silicone oil carrier in which the surfaces of the magnetic particles are modified with (a) a first surfactant comprising a hydrocarbon having at least one polar group and (b) a second surfactant comprising a silicone oil surfactant having at least one polar group and which is soluble in the silicone oil carrier.

摘要翻译： 一种铁磁性液体组合物，其包含在硅油载体中的细分散的磁性颗粒的胶体分散体，其中磁性颗粒的表面用（a）包含至少一个极性基团的烃的第一表面活性剂和（b）第二表面活性剂 包括具有至少一个极性基团并且可溶于硅油载体的硅油表面活性剂。

公开(公告)号：US5490425A

公开(公告)日：1996-02-13

申请号：US212272

申请日：1994-03-14

申请人： Kuldip Raj ,  James Torres ,  Susan Lanphear

发明人： Kuldip Raj ,  James Torres ,  Susan Lanphear

IPC分类号： G01L9/00 ,  G01L9/14

CPC分类号： G01L9/14 ,  G01L9/0089

摘要： Mechanically simple, reliable devices for measuring pressure or detecting pressures above a certain limit are disclosed. A representative device includes a magnet surrounded by one or more bands of a ferrofluid, and which is free to move within a nonmagnetic, generally elongated housing. In operation, the housing is oriented vertically, and the lower aperture exposed to the region of pressure to be sensed. The opposite end, which preferably contains another aperture, is exposed to a reference pressure (ordinarily the atmosphere) that remains isolated from the region of pressure to be sensed. Gravity draws the magnet downward, toward the bottom of the housing, while pressure at the lower aperture tends to force the magnet upward. When the force exerted by the pressure source exceeds the downward force of gravity, the magnet travels upward through the housing; this movement may be detected by an appropriate sensing arrangement, and is used to provide a warning signal or a quantitative pressure measurement.

摘要翻译： 公开了用于测量压力或检测压力高于某一极限的机械简单，可靠的装置。 代表性的装置包括由铁磁流体的一个或多个带包围的磁体，并且可以在非磁性的，大致细长的壳体内自由移动。 在操作中，壳体垂直取向，并且下孔暴露于要感测的压力区域。 优选地包含另一个孔的相对端被暴露于保持与要感测的压力区域隔离的参考压力（通常为大气）。 重力将磁铁向下拉，朝向壳体的底部，而在下孔处的压力倾向于迫使磁铁向上。 当压力源施加的力超过向下的重力时，磁体向上通过壳体; 该移动可以通过适当的感测装置来检测，并且用于提供警告信号或定量压力测量。

公开(公告)号：US4526382A

公开(公告)日：1985-07-02

申请号：US606586

申请日：1984-05-03

申请人： Kuldip Raj ,  Hanumaiah L. Gowda

发明人： Kuldip Raj ,  Hanumaiah L. Gowda

IPC分类号： F16C33/82 ,  F16J15/43 ,  G11B19/20 ,  F16J15/40

CPC分类号： F16J15/43

摘要： A compact, low cost, radially polarized multiple-stage ferrofluid seal apparatus which comprises a magnetically permeable housing, a magnetically permeable shaft to be sealed extending through the housing, one or more radially polarized permanent magnets to define a plurality of separate, spaced apart radial gaps between one polarized end of the permanent magnet and the surface of the shaft, ferrofluid in the radial gaps to define one or more separate, spaced apart ferrofluid O-ring seals about the surface of the shaft and a magnetically permeable bearing assembly adjacent to and in a magnetic flux relationship with at least one of the radial polarized magnets wherein the magnetic flux circuit extends between the radial polarized magnet, the housing, the bearing assembly, the shaft, and the ferrofluid in the radial gaps.

摘要翻译： 一种紧凑，低成本的径向偏振多级铁磁流体密封装置，其包括导磁壳体，待透过轴的待密封的延伸穿过壳体的一个或多个径向极化的永磁体，以限定多个分开的间隔开的径向 永磁体的一个极化端与轴的表面之间的间隙，在径向间隙中的铁磁流体，以限定围绕轴表面的一个或多个分离的间隔开的铁磁流体O形环密封件和与磁体 与至少一个径向极化磁体的磁通关系中，其中磁通电路在径向间隙中在径向极化磁体，壳体，轴承组件，轴和铁磁流体之间延伸。

公开(公告)号：US4478424A

公开(公告)日：1984-10-23

申请号：US574359

申请日：1984-01-27

申请人： Kuldip Raj

发明人： Kuldip Raj

IPC分类号： F16J15/43 ,  F16J15/40 ,  F16J15/54

CPC分类号： F16J15/43 ,  Y10S277/928

摘要： A ferrofluid seal apparatus and method, which ferrofluid seal apparatus comprises at least one ferrofluid seal about the surface of a rotatable shaft, the ferrofluid retained in a sealing relationship by magnetic flux from the ends of two pole pieces which define a cavity therebetween, and an interstage gap between the two pole pieces, which seal apparatus provides, within the single O-ring ferrofluid seal, a plurality of three separate regions of different magnetic-flux density, each of the regions having a different pressure value, the ferrofluid O-ring seal defining a ferrofluid exclusion seal between a first and second environment and the cavity, whereby the ferrofluid O-ring seal permits gas pressures from the cavity and the region environments to be transferred, on variations in pressures.

摘要翻译： 一种铁磁流体密封装置和方法，所述铁磁流体密封装置包括围绕可旋转轴的表面的至少一个铁磁流体密封，所述铁磁流体通过来自限定其间的空腔的两个极片的端部的磁通量保持密封关系， 该密封装置在单个O形环铁磁流体密封件内提供了两个不同磁通密度的三个分开的区域，每个区域具有不同的压力值的两个极片之间的间隔间隙，铁磁流体O形环 密封件在第一和第二环境和空腔之间限定铁磁流体排除密封，由此，在压力变化时，铁磁流体O形环密封件允许来自空腔和区域环境的气体压力被传递。

公开(公告)号：US4407508A

公开(公告)日：1983-10-04

申请号：US450339

申请日：1982-12-16

申请人： Kuldip Raj ,  Raoul Casciari

发明人： Kuldip Raj ,  Raoul Casciari

IPC分类号： F16J15/43 ,  F16J15/40

CPC分类号： F16J15/43

摘要： A single-pole-piece ferrofluid exclusion seal apparatus and exclusion seal system which comprises a single, annular pole piece to surround a shaft element to be sealed, and an annular permanent magnet secured to one surface of the pole piece in a magnetic-flux relationship, the single pole piece having a one end which extends into a close, noncontacting relationship with the surface of the shaft element to be sealed, to define a small radial gap between the surface of the shaft element and the one end of the pole piece, and a ferrofluid positioned within the radial gap, to provide a ferrofluid seal with the shaft element, the ferrofluid comprising a high magnetization-type ferrofluid, with the magnetic flux path of the single-pole-piece ferrofluid seal extending between the shaft, the ferrofluid in the radial gap, the single pole piece in the permanent magnet and the air gap between the magnet and the shaft.

摘要翻译： 单极铁磁流体排除密封装置和排除密封系统，其包括围绕要密封的轴元件的单个环形极片和以磁通关系固定在极靴的一个表面上的环形永磁体 单极片具有与要密封的轴元件的表面成一个非接触关系的一端，以在轴元件的表面和极片的一端之间形成小的径向间隙， 以及位于所述径向间隙内的铁磁流体，以提供与所述轴元件的铁磁流体密封，所述铁磁流体包括高磁化型铁磁流体，所述单极铁磁流体密封件的磁通量在所述轴，所述铁磁流体之间延伸 在径向间隙中，永磁体中的单极片和磁体与轴之间的气隙。

公开(公告)号：US4357021A

公开(公告)日：1982-11-02

申请号：US208287

申请日：1980-11-19

申请人： Kuldip Raj ,  Alan Schwartzman

发明人： Kuldip Raj ,  Alan Schwartzman

IPC分类号： F16J15/43 ,  F16J15/40

CPC分类号： F16J15/43

摘要： A ferrofluid rotary-shaft seal apparatus of extended seal life particularly adapted for use as an exclusion seal with a computer-disc-drive spindle, which seal apparatus comprises: an annular permanent magnet; first and second pole pieces of unequal width, one end of each pole piece extending into a close, noncontacting relationship with the surface of the shaft, to form a gap width between the one end of the pole piece and the surface of the shaft, the pole piece of greater width characterized by a tapered one end; and ferrofluid in the gap widths to form a ferrofluid O-ring seal, whereby, in operation, the ferrofluid, under the thinner pole piece, evaporates and forms an air gap, while the ferrofluid at the wider, tapered gap width provides extended seal life.

摘要翻译： 一种延长密封寿命的铁磁流体旋转轴密封装置，特别适合用作与计算机盘驱动主轴的排除密封，该密封装置包括：环形永磁体; 第一和第二极片的不等宽度，每个极片的一端延伸成与轴的表面接近，非接触的关系，以在极片的一端和轴的表面之间形成间隙宽度， 较大宽度的极片，其特征在于锥形一端; 和铁磁流体间隙宽度形成铁磁流体O形环密封，由此，在较薄的极片下方的铁磁流体蒸发并形成气隙，而较宽的锥形间隙宽度的铁磁流体提供延长的密封寿命 。

公开(公告)号：US20120049871A1

公开(公告)日：2012-03-01

申请号：US12869065

申请日：2010-08-26

申请人： Kuldip Raj

发明人： Kuldip Raj

IPC分类号： G01R27/08 ,  F16J15/43

CPC分类号： F16J15/43 ,  F16J15/3296

摘要： A failure indicator seal includes a nonmagnetic housing, a plurality of annular pole pieces having distal ends, the plurality of annular pole pieces disposed within the nonmagnetic housing, an annular, non-conducting magnet disposed between the pole pieces, a predefined quantity of magnetic fluid disposed between each of the distal ends of the plurality of annular pole pieces and the rotary shaft of a rotary feedthrough forming a plurality of magnetic fluid O-ring seals, and means for measuring resistance through the plurality of annular pole pieces, the plurality of magnetic fluid O-ring seals and the rotary shaft.

摘要翻译： 故障指示器密封件包括非磁性壳体，具有远端的多个环形极片，设置在非磁性壳体内的多个环形极片，设置在极靴之间的环形非导电磁体，预定量的磁性流体 设置在多个环形极片的每个远端和形成多个磁性流体O形环密封件的旋转馈通的旋转轴之间，以及用于通过多个环形极片测量电阻的装置，所述多个磁性 流体O型圈密封圈和旋转轴。

公开(公告)号：US06254781B1

公开(公告)日：2001-07-03

申请号：US09565011

申请日：2000-05-04

申请人： Kuldip Raj

发明人： Kuldip Raj

IPC分类号： B01D3508

CPC分类号： B03C1/32 ,  H01F1/44

摘要： Ferrofluid coated particles resulting from a ferrofluid materials separation process are washed with a solvent which is the same material as the liquid carrier employed in the ferrofluid. The result is a “dirty” solvent which is a very weak ferrofluid. The dirty solvent is then filtered or centrifuged to remove dust particles and other impurities and then the solvent is recovered by distillation in a distillation unit. The solvent can then be reused in the materials reclamation process. The residue in the distillation unit is surfactant-coated particles of ferrofluid. This residue is mixed with either clean or unprocessed solvent in the right proportion and the slurry is passed through an attritor to convert it to a high grade ferrofluid. The ferrofluid can also be reused in the materials separation process.

摘要翻译： 由铁磁流体材料分离过程产生的铁磁流体涂覆的颗粒用与铁磁流体中使用的液体载体相同的溶剂洗涤。 结果是一种非常弱的铁磁流体的“脏”溶剂。 然后将脏溶剂过滤或离心以除去灰尘颗粒和其它杂质，然后通过蒸馏在蒸馏单元中回收溶剂。 然后溶剂可以在材料回收过程中重复使用。 蒸馏单元中的残余物是表面活性剂涂覆的铁磁流体颗粒。 将该残余物与正确比例的清洁或未处理的溶剂混合，并将浆料通过磨碎机将其转化成高等级的铁磁流体。 铁水流体也可以在材料分离过程中重复使用。

公开(公告)号：US6103107A

公开(公告)日：2000-08-15

申请号：US177066

申请日：1998-10-22

申请人： Kuldip Raj

发明人： Kuldip Raj

IPC分类号： B03C1/32 ,  H01F1/44 ,  B01D35/06 ,  B01D21/26 ,  B01D37/00 ,  C01G49/08

CPC分类号： B03C1/32 ,  H01F1/44

摘要： Ferrofluid coated particles resulting from a ferrofluid materials separation process are washed with a solvent which is the same material as the liquid carrier employed in the ferrofluid. The result is a "dirty" solvent which is a very weak ferrofluid. The dirty solvent is then filtered or centrifuged to remove dust particles and other impurities and then the solvent is recovered by distillation in a distillation unit. The solvent can then be reused in the materials reclamation process. The residue in the distillation unit is surfactant-coated particles of ferrofluid. This residue is mixed with either clean or unprocessed solvent in the right proportion and the slurry is passed through an attritor to convert it to a high grade ferrofluid. The ferrofluid can also be reused in the materials separation process.

摘要翻译： 由铁磁流体材料分离过程产生的铁磁流体涂覆的颗粒用与铁磁流体中使用的液体载体相同的溶剂洗涤。 结果是一种非常弱的铁磁流体的“脏”溶剂。 然后将脏溶剂过滤或离心以除去灰尘颗粒和其它杂质，然后通过蒸馏在蒸馏单元中回收溶剂。 然后溶剂可以在材料回收过程中重复使用。 蒸馏单元中的残余物是表面活性剂涂覆的铁磁流体颗粒。 将该残余物与正确比例的清洁或未处理的溶剂混合，并将浆料通过磨碎机将其转化成高等级的铁磁流体。 铁水流体也可以在材料分离过程中重复使用。

公开(公告)号：US6068785A

公开(公告)日：2000-05-30

申请号：US21229

申请日：1998-02-10

申请人： Kuldip Raj ,  Lutful M. Aziz ,  Ronald E. Rosensweig

发明人： Kuldip Raj ,  Lutful M. Aziz ,  Ronald E. Rosensweig

IPC分类号： H01F1/34 ,  H01F1/44

CPC分类号： H01F1/44 ,  H01F1/445

摘要： A slurry is formed of particles of a non-magnetic oxide of iron (.alpha.-Fe.sub.2 O.sub.3), an oil carrier liquid and a surfactant. The slurry is then processed in an attrition mill where kinetic energy is applied to the slurry to convert the .alpha.-Fe.sub.2 O.sub.3 particles to magnetic iron oxide particles to form an oil-based ferrofluid. In order to increase the saturation magnetization of the resulting ferrofluid, a beneficial agent is brought into contact with the slurry during processing in the attrition mill. The beneficial agent can be a magnetic material, such as elemental iron, or can be water. A ferrofluid can also be formed by creating a powder of surfactant-coated magnetic particles and using an attrition mill to coat the particles with a second surfactant and suspend the coated particles in a carrier liquid.

摘要翻译： 浆料由铁（α-Fe 2 O 3），油载体液体和表面活性剂的非磁性氧化物的颗粒形成。 然后将浆料在磨浆机中加工，其中将动能施加到浆料上以将α-Fe 2 O 3颗粒转化为磁性氧化铁颗粒以形成油基铁磁流体。 为了提高所得铁磁流体的饱和磁化强度，在研磨机的加工过程中，有益剂与浆料接触。 有益剂可以是磁性材料，例如元素铁，或者可以是水。 还可以通过产生表面活性剂涂覆的磁性颗粒的粉末并使用研磨机用第二表面活性剂涂覆颗粒并将涂覆的颗粒悬浮在载体液体中来形成铁磁流体。