Ferrofluidics Corporation

Christian Ionescu

Kuldip Raj

Zhixin Li

Jay Greyson

A solenoid with liquid in the gaps between a moving and stationary element is disclosed that includes a secondary kick-back spring used to overcome the viscosity and surface tension effects of the liquid in the gap during the de-energizing phase of the solenoid action. Various secondary spring designs as well as surface shapes of the butt or plunger ends are possible in order to decrease the contact surface area of the ends of either the moving or stationary elements used in the solenoid and also are also used to decrease the viscosity and surface tension effects of the liquid.

Apparatus to reduce push back time in solenoid valves

A liquid level monitoring system, which monitors the level of liquid in a storage tank, includes a differential pressure sensor that uses a magnetic fluid, or ferrofluid, sensing element. The pressure sensor is U-shaped with a first one leg connected, via a first pressure chamber, to a bubbler tube that extends downwardly into the storage tank. The second leg of the U-shaped sensor connects to a second pressure chamber, which applies to the second leg a selected, fixed pressure. The pressure applied to the first leg of the sensor is proportional to the hydrostatic back pressure in the bubbler tube, which varies directly with the level of liquid in the storage tank. Wound around the legs of the pressure sensor are inductance coils. The inductances of these coils change as the ferrofluid sensing element moves within the sensor. Accordingly, the inductances change as the level of liquid in the storage tank varies. The inductor coils are connected to a control system which produces a control signal based on the differences of the inductances. This control signal thus varies essentially continuously with changes in the level of liquid in the storage tank. The control signal is preferably used to control a storage tank control system which includes various pumps. In response to the control signal, the pumps force liquid into or out of the storage tank, as appropriate. Alternatively, an array of sensing elements may be used to determine the position of the ferrofluid. Signals from the various sensing elements in the array are essentially encoded to produce an output signal that corresponds to the level of fluid in the storage tank.

Liquid level monitoring system having ferrofluid pressure sensor

An inclinometer device containing a magnet surrounded at each pole by a thin, discrete band of ferrofluid; these bands are retained against the magnet by its own magnetic field, and suffice to suspend the magnet within a nonmagnetic housing that may be open or closed to the atmosphere. In a first embodiment, a Hall element senses the axial position of the magnet, and a pair of inductor coils, positioned on opposite sides of the neutral point and configured to generate opposing magnetic fields, counteract the magnet's movement and restore it to the neutral position upon application of an appropriate electric current. The magnitude and direction of this restorative current indicate the extent and orientation of the tilt. In a second embodiment, the axial position of the magnet is sensed by a pair of split capacitors disposed on the housing and spaced apart from one another. A coil centered between the capacitors restores the magnet to its neutral position, and once again the magnitude and direction of the coil current is used to gauge the degree and orientation of incline.

Growing community of inventors

Nashua, NH, United States of America

Christian Ionescu