Abstract: One embodiment of the present invention relates to a variable capacitor that operates without moving mechanical parts. In this capacitor electrically conductive electrodes are separated by an enclosed chamber filled with an electrically conductive material. The electrically conductive material can freely vary its position within the chamber. The capacitance of the device will vary as position of the conductive material changes due to external mechanical motion (ex: rotation, vibration, etc.) of the device. Other embodiments of this device are also disclosed.

Abstract: A micro fluidic device and method for capacitive sensing. The device includes a fluid channel including an inlet at a first end and an outlet at a second end, a cavity region coupled to the fluid channel, and a polymer based membrane coupled between the fluid channel and the cavity region. Additionally, the device includes a first capacitor electrode coupled to the membrane, a second capacitor electrode coupled to the cavity region and physically separated from the first capacitor electrode by at least the cavity region, and an electrical power source coupled between the first capacitor electrode and the second capacitor electrode and causing an electric field at least within the cavity region. The polymer based membrane includes a polymer.

Abstract: The variable capacitance (1) according to the invention is based on a novel principle: a dielectric fluid (20) is placed in the air gap constituted by two capacitor electrodes (12, 14), the fluid being able to be displaced in a direction and outside the cavity (10) formed between said two electrodes (12, 14). Advantageously, the dielectric fluid (20) is displaced according to the principle of communicating vessels, with the presence of a second cavity (30) in fluidic relation with the first cavity. Actuation electrodes (46, 48) in the second cavity (30) induce the deflection of a membrane (44) in order to modify the relative heights of fluidic liquid in the two cavities (10, 30).

Abstract: A microfluidic device and method for capacitive sensing. The device includes a fluid channel including an inlet at a first end and an outlet at a second end, a cavity region coupled to the fluid channel, and a polymer based membrane coupled between the fluid channel and the cavity region. Additionally, the device includes a first capacitor electrode coupled to the membrane, a second capacitor electrode coupled to the cavity region and physically separated from the first capacitor electrode by at least the cavity region, and an electrical power source coupled between the first capacitor electrode and the second capacitor electrode and causing an electric field at least within the cavity region. The polymer based membrane includes a polymer.

Abstract: Capacitors (10,20,40,50,70,80) having a fluid dielectric material that is transported or undergoes a phase change are disclosed. The dielectric medium change results in a change in the total dielectric constant of the material between the electrodes (12, 14, 72, 74, 81, 82), thus changing the capacitance of the capacitors. Transporting or phase changing the dielectric fluids into and out of a the electric field of the capacitor, changes the effective dielectric constant and the capacitance of the capacitor.

Abstract: A sensor for the measurement of moisture in a flow of material, especially loose material such as meal material, grains, granulates and similar materials which are to be pressed to form feed pills in presses. The sensor comprises a tube piece of an electrically conductive material with circular cross-section, and an elongated pole which is of circular cross-section and is disposed with its longitudinal axis concentrically and electrically insulated in the tube piece, and which consists of an electrically conductive material. When the moist material flows between the inside surface of the tube piece and the outer side of the pole, the sensor works with the moist material's conductivity as a condenser for the capacitive detection of the moistness, which can be determined on the basis of the detection.

Abstract: A materials characterization test cell is disclosed. The test cell includes a housing including spacers for supporting sample insulation materials, and a channel disposed in the housing to permit the passage of oil through the housing. A pair of electrodes is provided to provide a mechanism for making polarization spectrum and/or streaming electrification measurements.

Abstract: A ceramic bodied sensor having helical metallized electrodes for measuring the capacitance of an oil-water-gas or oil-water mixture flowing through a central bore of the sensor is disclosed. The sensor generally is a hollow cylinder with an inner ceramic layer which is very thin, a thicker outer ceramic layer which forms a strong structural unit, and a pair of isolated metallized electrodes which are generally approximately located between the inner and outer ceramic layers. The inner ceramic layer, outer ceramic layer and metallized electrodes form a dense monolithic ceramic tube. The electrode plates are preferably identical in size and shape and are isolated from one another electrically so that a condenser is formed by the separated plates. The inner ceramic layer is preferably very thin to minimize its capacitance value in comparison to the capacitance value of the water-oil-gas or oil-water mixture flowing through the central bore of the sensor.

Abstract: A microbridge is used for the accurate measuring of time varying shear forces in the presence of fluctuating pressure. A microdimensioned plate is suspended by arms to form a microbridge. The microdimensions enable the smallest turbulence scales of interest to be sensed uniformally throughout the entire surface of the plate. The cavity beneath the microbridge is so small that a viscous drag is created in the air within the cavity and dampens normal movement of the plate. The microdimensions in conjunction with the damping effect of the cavity enable the sensor to be substantially insensitive to pressure and thus sense lateral forces independent of normal forces. The microbridge sensor is fabricated by surface micromachining. A sacrificial layer is deposited over a substrate. A structural layer is deposited and patterned to form the plate and support arms over the sacrificial layer.

Abstract: A liquid sensor system particularly suitable for commercial washing machines for drinking glasses and soft drink dispensers employs a capacitive detector providing a tortuous path through which the liquid passes and constituting part of the dielectric of the resultant capacitor. The pumps supplying the liquid through the capacitor to the dispensing means are controlled in accordance with the capacitance, as measured by a circuit. A preferred measuring circuit comprises a pulse generator; one series of pulses split from the generator output is delayed by a fixed period and fed to a flip-flop, while the second series also from the generator output are delayed by a period dependent upon the sensor capacitance and are also fed to the flip-flop, the output of which is dependent upon which series of pulses is in advance of the other. The circuit also provides for automatic adjustment of its sensitivity upon start-up or reset to adjust for differences in the sensors and the liquids.

Abstract: A variable capacitance device generally intended for use in measuring the mass flow of air while passing through an engine-manifold. The device is capable of responding to the impingement of a stream of air on its flexible capacitor plate located within an air conveying duct, in which the impingement tends to bend the flexible capacitor plate over the curved surface of a rigid electrically insulated capacitor plate. The gradual bending of the flexible capacitor plate over the curved surface of the rigid capacitor plate changes the capacitance of the device at rate proportional to the rate of change in the mass-flow of the gas.

Abstract: Gas flow metering using a capacitance measurement and comprising a taut elastomeric membrane, preferably tubular in form, which expands or contracts as a function of flow rate past it to an extent determined by Bernouilli's principle. The thus changing distance between this membrane and one or more external electrodes measured by capacitance change or other means is correlatable with the instantaneous flow rate and such measurement can be made essentially without regard to entrained solids or liquids in the gas flow, phase and temperature changes (moderate) within the gas flow or mixture or changing composition therein and with rapid response and low back pressure.

Abstract: A capacitance probe sensor device is disclosed which has a probe formed of KYNAR insulated wire spaced from an uninsulated metallic ground electrode. An oscillator and associated capacitance-resistance network connected to the probe serve to provide a linear output voltage proportional to the change of capacitance between the insulated wire and the ground electrode. The capacitance probe sensor device can be used in a number of applications. They include the measurement of water level, the determination of a liquid's flow rate, and the moisture content of soil.

Abstract: A capacitance sensing device for detecting the amount of material flowing through a passage includes layers of disk-shaped insulating substrates having electrode films formed on surfaces thereof facing each other, and the insulating substrates are supported by an insulating support member as a unit and spaced from each other. The electrode films are alternately connected by a pair of conductors to form a capacitor. Electric circuit elements, forming a detection circuit which is connected to the pair of conductors and which detects a change in capacitance of the capacitor depending on the amount of material flowing through the spaces between the electrode films, are formed on the outer surface of an outermost one of the substrates in a form of a monolithic circuit or a hybrid circuit.

Abstract: This invention relates to a capacitance densitometer for determining the flow regime of a two-phase flow system. A two-element capacitance densitometer is used in conjunction with a conventional single-beam gamma densitometer to unambiguously identify the prevailing flow regime and the average density of a flowing fluid.