Exxon Research and Engineering Company

Ferrofluidics Corporation

Ferrotec Corporation

Ferrotec (usa) Corporation

Ronald E Rosensweig

Kuldip Raj

Theodorus M Wortel

Lutful M Aziz

Klaas Hoving

George Ciprios

Dominicus J Van Der Vleugel

Lovat V Rees

Markus Zahn

Shiro Tsuda

Thomas J Black, Jr

An audio speaker has a driver unit having a support frame with a central portion forming a magnetic structure defining an annular gap around a central magnetic post, a vibration system having a diaphragm and a voice coil, the voice coil is attached to one side of the diaphragm where the vibration system is fixed to the support frame and where the voice coil is movably mounted in the annular gap, and a magnetic fluid disposed in the annular gap only in a space between one side of the voice coil and a surface of the annular gap having a higher magnetic flux density.

Ferrofluid centered voice coil speaker

Magnetic fluid seals containing housings, magnets, pole pieces, gaps, magnetic fluids, shafts and bearings of standard type are modified to permit operation at two levels of magnetic intensity in the gaps. During exposure to the operating pressure difference that a seal is designed to withhold, the magnetic field intensity in the gaps is maintained at a relatively low intensity. Subsequently, the magnetic field intensity in the gaps is increased to yield burst-free operation. Various embodiments for adjusting the magnetic field intensity are disclosed. These include: magnetic fluid seal with a variable magnet to pole-block spacing; seal with hollow-shaft flux intensifier; seal with surrounding flux diverter; and seal with an internal magnetic coil that furnishes opposing magnetomotive force.

Non-bursting ferrofluid seal

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.

Method for manufacturing oil-based ferrofluid

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.

Stable polysiloxane ferrofluid compositions and method of making same

A system that will indicate tire inflation. A two-dimensional array of sensors is used to determine the distribution of contact forces over the footprint of a pneumatic tire. A neural network may be employed to classify the patterns of force sensed in this manner, and to closely estimate the actual tire inflation pressure.

Tire inflation sensor

A system that will indicate tire inflation and vehicle velocity. An array of strain gage sensors is used to determine the distribution of contact forces along the width of a pneumatic tire. A neural network may be employed to classify the patterns of force sensed in this manner. Additional processing of the data permits vehicle velocity to also be determined.

Tire inflation and velocity sensor

Magnetizable adsorbent particles suitable for use in a magnetically stabilized fluidized bed and with a smaller particle size than conventionally formed composite adsorbents are prepared by introducing magnetizable particles such as magnetite or iron into a reaction mixture for forming a zeolite having adsorbent properties, such as zeolite Y. The zeolite is formed as a coating on the magnetizable particle.

Separation of hydrocarbons using magnetizable adsorbents

This invention relates to a fluidized bed process. More particularly, the present invention is a process for operating a magnetically stabilized fluidized bed by using a magnetizable fluid to fluidize solid particulate nonmagnetizable fluidizable particles. The operating conditions are such that there is substantially no random motion or time-varying pressure fluctuation as measured at a point within the bed.

Process for magnetically stabilizing a fluidized bed containing

Magnetizable adsorbents

This invention relates to a process for magnetically stabilizing the operation of contactor columns containing immiscible fluids passing in dispersed countercurrent flow. The process operates by including, in an appropriate fluid phase, a magnetizable component in an amount which does not substantially change the nature of the liquid in that phase and, further, imposing upon at least a portion of the column containing dispersed phases, a magnetic field sufficient to result in substantially diminished radial mixing of the phase containing the magnetizable substance and diminished coalescence of the dispersed phase. The phase containing the magnetizable component passes through the stabilized zone in substantial plug flow.

Process for magnetically stabilizing contactor columns containing

A process for the recovery of a fluid from a porous formation whereby fingering effects are controlled by applied magnetic field. The process comprises injecting a displacement fluid and ferrofluid, or a ferrofluid-containing displacement fluid, in an effective amount to displace fluid from the formation, applying a magnetic field containing a gradient of field intensity across said formation, driving the displaced fluid through the formation and recovering the displaced first fluid.

Magnetized drive fluids

A fluidized bed process is disclosed which comprises subjecting a bed comprised of solid particulate magnetizable, fluidizable material within an external force field wherein at least a portion of the bed containing said solid particulate magnetizable and fluidizable material and fluidizing fluid are subjected to a nontime varying and substantially uniform applied magnetic field having a substantial component along the direction of the external force field such that said solid particulate magnetizable and fluidizable material has a component of magnetization along the direction of the external force field and wherein at least a portion of said bed containing the solid particulate magnetizable and fluidizable material is fluidized by a flow of fluid opposing said external force field at a superficial fluid velocity ranging between:

Composite zeolitic magnetic material

A hydrotreating process wherein composite catalyst particles are formed into a magnetically stabilized fluidized bed and contacted with a fluid, preferably gas. The composition is one which exhibits high induced magnetism in a small applied magnetic field when formed into a magnetically stabilized fluidized bed. The particles contain a non-ferromagnetic component, or components, composited with one or a plurality of elongated ferromagnetic components, oriented and present in each of said particles in relatively low concentration, based on the total volume of the particles.

Composition and hydrotreating process for the operation of a

A composition which exhibits high induced magnetism in a small applied magnetic field when formed into a magnetically stabilized fluidized bed and which comprises particles containing a nonferromagnetic component, or components, composited with one or a plurality of elongated ferromagnetic components oriented and present in each of said particles in relatively low concentration, based on the total volume of the particles; and a process wherein such composite particles are formed into a magnetically stabilized fluidized bed and contacted with a fluid, preferably gas.

Growing community of inventors

Summit, NJ, United States of America

Ronald E Rosensweig