公开(公告)号：US4445696A

公开(公告)日：1984-05-01

申请号：US468339

申请日：1983-02-22

申请人： Kuldip Raj ,  Ronald Moskowitz ,  Raymond Rodier

发明人： Kuldip Raj ,  Ronald Moskowitz ,  Raymond Rodier

IPC分类号： F16J15/43 ,  F16J15/40

CPC分类号： F16J15/43 ,  Y10S277/913

摘要： A single-stage, ferrofluid magnetic seal apparatus and method which comprises: an annular, permanent-magnet ring element adapted to surround a shaft to be sealed, which shaft extends between first low-pressure and second high-pressure; first and second pole pieces in a magnetic-flux relationship with the permanent magnet, and having one and the other ends, the other end extending into a close, noncontacting relationship with the surface of the shaft, to define a radial gap therebetween; a plurality of stages formed in the radial gap under the other end of the second pole piece, which pole piece is placed toward the high-pressure side the environment, and the radial gap under the first pole piece, placed toward the low-pressure side of the environment, being shallow and generally less than about 2 mils; and ferrofluid in the radial gap under the other end of the second pole piece which forms a plurality of separate O-ring ferrofluid seals of defined pressure capacity, thereby providing a single-stage, ferrofluid magnetic seal apparatus and method, which seal apparatus has a reduced tendency to permit unpredictable air bursts, when installed about the rotary shaft between first and second pressure environments.

摘要翻译： 一种单级铁磁流体密封装置及方法，其特征在于，包括：环状的永久磁铁环元件，其适于围绕待密封的轴，所述轴在第一低压和第二高压之间延伸; 第一和第二极靴与永久磁铁具有磁通量关系，并且具有另一端和另一端，其另一端与轴的表面延伸成一个非接触的关系，以在它们之间形成径向间隙; 形成在第二极靴的另一端的径向间隙内的多个级，该极片朝向高压侧放置在环境中，第一极片下方的径向间隙朝向低压侧 的环境，浅，通常小于2密耳; 和第二极靴另一端的径向间隙中的铁磁流体，形成具有规定压力容量的多个分离的O形环铁磁流体密封件，从而提供单级铁磁流体磁性密封装置和方法，该密封装置具有 当在第一和第二压力环境之间围绕旋转轴安装时，允许不可预测的空气爆炸的趋势减小。

公开(公告)号：US4927164A

公开(公告)日：1990-05-22

申请号：US229640

申请日：1988-08-08

申请人： Kuldip Raj ,  Joseph Moses ,  Ronald Moskowitz ,  Frank Bloom

发明人： Kuldip Raj ,  Joseph Moses ,  Ronald Moskowitz ,  Frank Bloom

IPC分类号： B29C41/12 ,  F16J15/43 ,  H01F7/02

CPC分类号： B29C41/12 ,  F16J15/43 ,  H01F7/0205 ,  Y10S277/94

摘要： In a ferrofluid seal which comprises a magnet and at least one pole piece, the pole piece is fabricated from a ferromagnetic material which directly bonds to the magnet face. Since the pole piece material directly bonds to the magnet, no additional adhesive is necessary. Thus, the conventional steps of applying an adhesive and mounting pole pieces on the magnet are eliminated. In addition, voids and bubbles in the adhesive are eliminated, thus, enhancing seal integrity.In one embodiment, the ferromagnetic material is a ferromagnetic epoxy compound comprising a mixture of conventional epoxy materials plus a fine powder of ferromagnetic material such as iron, cobalt, nickel or various metal alloys.

公开(公告)号：US4890850A

公开(公告)日：1990-01-02

申请号：US182510

申请日：1988-04-18

申请人： Kuldip Raj ,  Ronald Moskowitz ,  Frank Bloom

发明人： Kuldip Raj ,  Ronald Moskowitz ,  Frank Bloom

IPC分类号： F16J15/43

CPC分类号： F16J15/43

摘要： A ferrofluid seal wherin the amount of ferrofluid which may be used is increased by tapering the gap in which the ferrofluid is retained from one end of the gap to the other. One side of this gap is the magnet and, where used, pole pieces used to generate the magnetic field retaining the sealing ferrofluid, and the other side is a wall forming the opening to be sealed. The tapering of the gap width may be achieved by tapering either side forming the gap or by tapering both sides. The taper is preferably uniform from one end of the gap to the other.

摘要翻译： 可以使用可以使用的铁磁流体量的铁磁流体密封通过将铁磁流体从间隙的一端保持的间隙逐渐变细而增加。 该间隙的一侧是磁体，并且在使用时，用于产生保持密封铁磁流体的磁场的极片，另一侧是形成待密封的开口的壁。 间隙宽度的渐缩可以通过使形成间隙的任一侧变细或通过使两侧逐渐变细来实现。 锥度优选从间隙的一端到另一端是均匀的。

公开(公告)号：US5018751A

公开(公告)日：1991-05-28

申请号：US373328

申请日：1989-06-28

申请人： Kuldip Raj ,  Ronald Moskowitz ,  Joseph Moses ,  James Bonvouloir ,  Frank Bloom

发明人： Kuldip Raj ,  Ronald Moskowitz ,  Joseph Moses ,  James Bonvouloir ,  Frank Bloom

IPC分类号： F16J15/43

CPC分类号： F16J15/43

摘要： A long-life, stacked pole-piece magnetic fluid seal for sealing between a housing and magnetically permeable shaft, in one embodiment is comprised of an annular magnet, having poles of opposite polarity on first and second end surfaces thereof, an annular, magnetically permeable primary pole-piece axially abutting the first end surface of the magnet, and one or more annular, magnetically permeable secondary pole-pieces stacked axially adjacent the primary pole-piece and separated therefrom and from each other by one or more annular spacers which define intermediate spaces between the pole-pieces. The pole-pieces are in a closely-spaced, non-contacting relationship with the shaft to define one or more radial gaps which, in conjunction with the intermediate spaces collectively form an annular ring in which a magnetic fluid is disposed and retained. In a second embodiment, the annular magnet is separated from the primary pole piece by a spacer which defines an intermediate space therebetween. The magnet and primary pole-piece are in closely-spaced, non-contacting relationships with the shaft to define first and second gaps respectively, which, in conjunction with the intermediate space, collectively form an annular ring in which a magnetic fluid is disposed and retained.

摘要翻译： 在一个实施例中，用于在壳体和导磁轴之间进行密封的长寿命堆叠的极片磁性流体密封件包括环形磁体，其具有在其第一和第二端面上具有相反极性的极性，环形磁导率 主磁极件轴向地邻接磁体的第一端面，以及一个或多个环形的导磁次级极片，其轴向邻近初级极片堆叠并且与其分离，并且由一个或多个环形间隔件相互间隔开， 极片之间的空间。 极靴与轴形成一个紧密间隔的非接触关系，以限定一个或多个径向间隙，这些中间空间与中间空间共同形成环形环，磁环流体被布置和保持在环形环中。 在第二实施例中，环形磁体通过限定其间的中间空间的间隔件与主极片分离。 磁体和初级极片与轴紧密隔开，非接触的关系，以分别限定第一和第二间隙，这些中间空间与中间空间共同形成环形环，磁环中设置有磁性流体; 保留。

公开(公告)号：US4772032A

公开(公告)日：1988-09-20

申请号：US20460

申请日：1987-03-02

申请人： Kuldip Raj ,  Ronald Moskowitz

发明人： Kuldip Raj ,  Ronald Moskowitz

IPC分类号： F16J15/43 ,  G11B19/20 ,  G11B33/14 ,  F16J15/40 ,  F16J15/54

CPC分类号： G11B33/1473 ,  F16J15/43 ,  G11B19/2009 ,  Y10S277/919

摘要： A bearing and magnetic fluid seal assembly includes a shaft mounted by axially spaced-apart bearings for rotation relative to a housing. A magnetic fluid seal includes an annular magnet axially positioned between the bearings in the space that is wasted and not utilized for any purpose, and a thin, disk-like annular polepiece positioned between one of the bearings and the environment to be protected by the seal. Magnetic flux from the magnet is conducted by a magnetically permeable housing or shaft to an annular gap between the inside diameter of the polepiece and the shaft. A magnetic fluid is retained in the gap by the magnetic flux, thereby providing an exclusion seal. Embodiments utilizing radially and axially polarized magnets are provided. A magnetic fluid seal can be provided at each end of the assembly. The bearings supporting the shaft can be magnetically permeable or nonmagnetic. The seal(s) can be electrically conducting or nonconducting depending upon the type of ferrofluid used.

公开(公告)号：US5429000A

公开(公告)日：1995-07-04

申请号：US171230

申请日：1993-12-21

申请人： Kuldip Raj ,  Ronald Moskowitz

发明人： Kuldip Raj ,  Ronald Moskowitz

IPC分类号： G01L9/00

CPC分类号： H01F21/06 ,  C23C14/08 ,  G01L9/0094 ,  H01F1/447

摘要： A differential pressure sensor includes a ferrofluid sensing element, or slug, that changes position in a tapered magnetic field in response to a pressure differential. The ferrofluid slug is contained in a tube and moves within the tapered magnetic field, which is perpendicular to the longitudinal axis of the tube. The field has a maximum flux density at its center and tapers off in both axial directions from its center. In response to a pressure differential of zero, the slug is centered in the field. In response to a non-zero pressure differential, the slug moves to the position in the field where the net magnetic forces equal the pressure differential. The position of the slug is sensed by sensing elements which produce output signals that vary according to the position of the slug. In a preferred embodiment the sensing elements are pickup coils that are positioned to encompass the range of movement of one end of the slug, or are a pair of pickup coils positioned, respectively, to encompass the range of movement of the two ends of the slug. The ferrofluid slug thus acts as a movable core for the pickup coil(s). As the ferrofluid slug moves, it changes the relative inductances of the pickup coils. The one coil or the pair of coils are connected in a bridge circuit, which produces an output signal that varies according to the changing inductances, and thus, the pressure differential.

摘要翻译： 差压传感器包括响应于压力差在锥形磁场中改变位置的铁磁流体感测元件或块状物。 铁磁流体塞被包含在管中并且在与管的纵向轴线垂直的锥形磁场内移动。 该磁场在其中心具有最大磁通密度，并从其中心沿轴向逐渐变细。 响应于零压力差，磁芯在磁场中居中。 响应于非零压力差，排料移动到场中的净磁力等于压差的位置。 通过感测元件来检测芯塞的位置，这些元件产生根据芯块的位置而变化的输出信号。 在优选实施例中，感测元件是拾取线圈，其被定位成包围芯块的一端的移动范围，或者是一对拾取线圈，其分别被定位成包围块的两端的移动范围 。 铁磁流体块因此用作用于拾取线圈的可动铁芯。 当铁磁流体移动时，它会改变拾取线圈的相对电感。 一个线圈或一对线圈连接在桥接电路中，产生根据变化的电感而变化的输出信号，从而产生压差。

公开(公告)号：US4252328A

公开(公告)日：1981-02-24

申请号：US145828

申请日：1980-05-01

申请人： Kuldip Raj ,  Ronald Moskowitz ,  Raoul Casciari ,  Alvan F. Chorney

发明人： Kuldip Raj ,  Ronald Moskowitz ,  Raoul Casciari ,  Alvan F. Chorney

IPC分类号： F16C33/10 ,  F16J15/43 ,  G11B17/028 ,  G11B33/14 ,  F16J15/16 ,  F16J15/40

CPC分类号： G11B33/1473 ,  F16C33/1035 ,  F16J15/43

摘要： A self-activating ferrofluid-seal apparatus for a memory-disc-drive shaft, which seal apparatus comprises a ring magnet and a pair of pole pieces which form a cavity therebetween, a closed loop of a plastic tubular container with ferrofluid positioned within the cavity, and a penetration clamp to penetrate the plastic container prior to installation of the shaft element.

摘要翻译： 一种用于存储盘驱动轴的自激活铁磁流体密封装置，该密封装置包括环形磁体和在其间形成空腔的一对极片，塑料管状容器的闭合环，其中铁磁流体位于空腔内 ，以及在安装轴元件之前穿透塑料容器的穿透夹具。

公开(公告)号：US5461677A

公开(公告)日：1995-10-24

申请号：US285772

申请日：1994-08-03

申请人： Kuldip Raj ,  James Bonvouloir ,  Ronald Moskowitz

发明人： Kuldip Raj ,  James Bonvouloir ,  Ronald Moskowitz

IPC分类号： H04R9/02 ,  H04R9/06 ,  H04R25/00

CPC分类号： H04R9/06 ,  H04R9/025 ,  H04R9/027 ,  H04R2209/022

摘要： A loudspeaker including one or more secondary magnets positioned proximate to an opening of a gap through which a voice coil moves, to capture escaping ferrofluid and return the fluid to the gap. The secondary magnets have axial poles and are oriented, relative to a speaker magnet, to enhance the radial magnetic flux within the gap and to diminish the flux of a fringe field axially adjacent to the gap. When ferrofluid escapes from the gap, it is captured and held by one of the secondary magnets at a distal edge, which is a position of relatively high flux density within the magnetic field of the secondary magnet. When the amount of fluid held by the secondary magnet forms a sufficiently large miniscus, additional fluid captured by the magnet flows to a second region of relatively high flux density in the field of the secondary magnet and is drawn into the voice coil gap.

摘要翻译： 扬声器包括一个或多个次级磁体，其位于靠近音圈移动的间隙的开口处，以捕获逃逸的铁磁流体并将流体返回到间隙。 次级磁体具有轴向极点并且相对于扬声器磁体定向，以增强间隙内的径向磁通量并且减小与间隙轴向相邻的边缘磁场的通量。 当铁磁流体从间隙中逸出时，它被一个次级磁体捕获并保持在远端边缘，该远端是次级磁体磁场内磁通密度相对较高的位置。 当由二次磁体保持的流体的量形成足够大的液面时，由磁体捕获的另外的流体流到次级磁体的磁场中的相对高的磁通密度的第二区域并被吸入到音圈间隙中。

公开(公告)号：US4830384A

公开(公告)日：1989-05-16

申请号：US68012

申请日：1987-06-29

申请人： Kuldip Raj ,  Ronald Moskowitz

发明人： Kuldip Raj ,  Ronald Moskowitz

IPC分类号： F16J15/43

CPC分类号： F16J15/43

摘要： A compact long-life magnetic fluid seal for sealing between a housing and a magnetically permeable rotating shaft includes an annular magnet having a closely-spaced, noncontacting relationship with the shaft to define a first gap and an annular pole piece axially abutting the magnet and having a closely-spaced, noncontacting relationship with the shaft to define a second gap. The first gap has a slightly larger radial dimension than the second gap, and the first and second gaps together define an elongated annular space for retention of a magnetic fluid. The outer edges of the pole piece and magnet inner surfaces can be rounded to limit splashing of the magnetic fliud. In another embodiment, a magnetic fluid seal includes first and second pole pieces axially abutting opposite ends of an annular magnet. The magnet has a slightly larger inside diameter than either of the pole pieces. The pole pieces and the magnet together define an elongated annular gap for retention of magnetic fluid. The seal structure permits introduction of a relatively large volume of magnetic fluid, thereby extending the seal life, while maintaining a short axial dimension.

公开(公告)号：US4407518A

公开(公告)日：1983-10-04

申请号：US455065

申请日：1983-01-05

申请人： Ronald Moskowitz ,  Kuldip Raj ,  James L. Kern

发明人： Ronald Moskowitz ,  Kuldip Raj ,  James L. Kern

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

CPC分类号： F16J15/43 ,  Y10S277/928

摘要： A nonbursting ferrofluid seal apparatus and system which comprises an annular permanent magnet and annular first and second pole pieces, one end of the pole pieces defining a single-stage ferrofluid seal under one end of one pole piece and a multiple-stage ferrofluid seal under the one end of the other pole piece with the surface of the shaft element with which the seal is employed, the first and second pole pieces and the magnet defining therebetween an interstage volume between the single-stage ferrofluid seal and the multiple-stage ferrofluid seal, and conduit means extending into the interstage volume, and means to maintain a desired pressure in the stage volume, to maintain the first-stage ferrofluid seal in a stable, nonbursting condition, when the seal apparatus is employed between high- and low-pressure environments.

摘要翻译： 一种非爆破式铁磁流体密封装置和系统，其包括环形永磁体和环形第一和第二极片，所述极片的一端限定在一个极片的一端处的单级铁磁流体密封件和在多个级别的磁流体密封件下面的多级铁磁流体密封件 另一个极靴的一端与轴元件的表面一起使用密封件，第一和第二极片和磁体在其间限定了单级铁磁流体密封件和多级铁磁流体密封件之间的级间容积， 以及延伸到级间体积中的管道装置，以及在阶段体积中保持所需压力的装置，以便在密封装置用于高压和低压环境之间时将第一级铁磁流体密封件保持在稳定的非爆破状态 。