132results about "Fluid pressure measurement using inductance variation" patented technology

A pressure sensing apparatus for operative arrangement within an environment, having: a sensor comprising a hermetically-sealed receptacle, at least one side of which has an flexible membrane to which a magnetically hard element is attached. Enclosed within the receptacle is a magnetostrictive element that vibrates in response to a time-varying magnetic field. Also included is a receiver to measure a plurality of successive values for magneto-elastic emission intensity of the sensor taken over an operating range of successive interrogation frequencies to identify a resonant frequency value for the sensor. Additional features include: (a) the magnetically hard element may be adhered to an inner or outer side of, or embedded within, the membrane; (b) the magnetostrictive element can include one or more of a variety of different pre-formed, hardened regions; (c) the magneto-elastic emission may be a primarily acoustic or electromagnetic emission; and (d) in the event the time-varying magnetic field is emitted as a single pulse or series of pulses, the receiver unit can detect a transitory time-response of the emission intensity of each pulse (detected after a threshold amplitude value for the transitory time-response is observed). A Fourier transform of the time-response can yield results in the frequency domain. Also, an associated method of sensing pressure of an environment is included that uses a sensor having a magnetostrictive element to identify a magneto-elastic resonant frequency value therefore. Using the magneto-elastic resonant frequency value identified, a value for the pressure of the environment can be identified.

A system for measuring and converting to an observer intelligible form an internal physiological parameter of a medical patient. The invention allows transcutaneous telemetry of the measured information intracranial pressure via a system which includes a patient implanted sensor module and a processing and display module which is external of the patient and optically coupled to the sensor module via an external coupling module. A sensor within the implanted module transduces the measured information and a near infrared (NIR) emitter transmits this telemetry information when interrogated by the complementary external coupling module. Alternately, a set of tuned inductor-crystal circuits versus inductor-crystal comprised in part of a cylindrical crystal oscillator whose resonant frequency is sensed by a dipper circuit arrangement is provided. Power for the sensor module is derived inductively through rectification of a transcutaneously-applied high-frequency alternating electromagnetic field which is generated by a power source within the external coupling module, in concept much like a conventional electrical transformer. A computer within the processing and display module calculates the parameter value from the telemetry signal and represents this data either in numerical, graphical, or analog format.

A disposable pressure sensor includes a substrate and a pressure diaphragm formed upon the substrate. A sensor coil can be provided, comprising a capacitor and an inductor formed on the substrate and surrounded by the pressure diaphragm. The ferrite core is located proximate to the sensor coil, such that when the pressure diaphragm is exposed to a pressure, the diaphragm moves close to the inductor or the capacitor, thereby resulting in a change in the capacitor or the inductor and an indication of pressure. The capacitor can be implanted as an adjustable, trimmable or variable capacitor. The inductor may also be provided as an adjustable or variable inductor and can include the use of a variable capacitor and a PVDF based piezoelectric transducer. When the PVDF layer is under pressure, it can generate an electric field across the interdigital transducer and transmit a signal thereof through an antenna.

The invention relates to a flexible, resilient capacitive sensor suitable for large-scale manufacturing. The sensor comprises a dielectric, an electrically conductive layer on the first side of the dielectric layer, an electrically conductive layer on a second side of the dielectric layer, and a capacitance meter electrically connected to the two conductive layers to detect changes in capacitance upon application of a force to the detector. The conductive layers are configured to determine the position of the applied force. The sensor may be shielded to reduce the effects of outside interference.

A system for measuring and converting to an observer intelligible form an internal physiological parameter of a medical patient. The invention allows transcutaneous telemetry of the measured information intracranial pressure via a system which includes a patient implanted sensor module and a processing and display module which is external of the patient and optically coupled to the sensor module via an external coupling module. A sensor within the implanted module transduces the measured information and a near infrared (NIR) emitter transmits this telemetry information when interrogated by the complementary external coupling module. Power for the sensor module is derived inductively through rectification of a transcutaneously-applied high-frequency alternating electromagnetic field which is generated by a power source within the external coupling module, in concept much like a conventional electrical transformer. A computer within the processing and display module calculates the parameter value from the NIR telemetry signal and represents this data either in numerical, graphical, or analog format.

In oil-filled pressure sensors, the measured pressure is applied to a compliant isolation diaphragm, which causes the pressure of the internal oil to increase until it equals the external pressure. The pressure is sensed by a pressure sensing capsule, such as a MEMS piezoresistive pressure sensor. The invention incorporates an electromagnetic force generator, such as a coil and a magnetic core, within the pressure sensor in order to generate simulated pressure. When the coil is energized, the electromagnetic field creates a uniform distributed force, which moves the isolation diaphragm directly, or via an external flexure, in a manner to cause the pressure of the internal oil to increase, which is sensed by the pressure sensing capsule, which responds by producing an output signal proportional to the electromagnetic force. The simulated pressure is employed in order to perform sensor operation monitoring and self-calibration via measurement of the output signal.

A differential pressure flow sensor system comprises a disposable flow sensor which has upstream and downstream pressure sensing devices for detecting a differential pressure in a flow channel. Each sensing device comprises a diaphragm, a capacitor and an inductor electrically coupled to the capacitor so as to form an LC tank circuit. The capacitor and/or inductor can be mechanically coupled to the diaphragm such that a deflection of the diaphragm in response to fluid pressure applied thereto causes a change in the resonant frequency of the LC tank. The differential pressure and flow rate can be determined by detecting changes in the resonant frequency using interrogation electronics which can wirelessly interrogate the devices. A calibration capacitor and/or inductor can be formed on each sensing device and trimmed thereon for calibration purposes. Such pressure flow systems can be implemented in medical applications.

A temperature independent pressure sensor for selectively determining pressure is provided. The sensor comprises a resonance sensor circuit, a pressure sensitive component disposed on the sensor circuit, and an electromagnetic field modulator. A temperature independent pressure sensor system comprises a resonance sensor circuit, a pressure sensitive component disposed on the sensor circuit, an electromagnetic field modulator, and a processor that generates a multivariate analysis of sensor response pattern that is based on a change in an environmental pressure of the sensor system. A method of detecting a pressure response pattern in a temperature independent manner is also provided.

A pressure gage adapted to provide a mechanical indication of a sensed pressure and to provide an electrical signal indicative of the sensed pressure. The pressure gage includes a housing having a first fluid pressure chamber, a second fluid pressure chamber, and flexible diaphragm separating the first fluid pressure chamber from the second fluid pressure chamber. A magnet is coupled to the diaphragm such that movement of the diaphragm causes a related movement of the magnet. A helix is located adjacent to the magnet and a pointer is attached to the helix for conjoint rotation with a helix about a rotational axis. A Hall effect sensor is also located adjacent the magnet. Movement of the magnet in response to movement of the diaphragm rotates the helix and the pointer to provide a mechanical indication of the pressure sensed by the diaphragm, and the movement of the magnet causes the Hall effect sensor to generate an electrical signal indicative of the pressure sensed by the diaphragm.

A tire pressure reporting and warning system employs low-cost passive magnetically coupled pressure senders within the tires. These senders employ permanent magnets that rotate in response to pressure and may conveniently be mounted on the valve stem. A sender comprises a high-permeability helical ribbon that translates in response to pressure and penetrates a magnetic circuit. The magnetic circuit rotates into alignment with the helical ribbon. A novel feature of this invention is the dual-purpose use of the magnet both as a means for producing rotation in response to pressure and simultaneously for producing the remotely sensed external magnetic field. The direction and strength of the external field depends both on the rotation of the magnet with respect to the tire and on the overall orbital motion as the tire rotates. Remote pressure readers at each wheel respond to the magnetic field components and interpret the response asymmetry in terms of tire pressure by continuously calculating response skew as the tires rotate. Analyzing skew obviates the need for tire rotation sensing and timing and eliminates magnetic strength effects. No special alignment is required between senders and readers, so the readers may be mounted rather arbitrarily nearby the vehicle wheels.

An elastic material for pressure measurement, containing an elastic resin composition having at least either a urethane bond or a urea bond and being obtained by reacting an isocyanate with (A) a linear polyol and then curing the obtained prepolymer with use of a curing agent having two —NH₂ groups in one molecule.

A modified inductive pressure sensor for detecting operating parameters of an electric household appliance such as a washing or drying machine, provided with a relatively movable component with respect to the carcass (tank or basket), of the type including a rigid casing accommodating a deformable membrane sensitive to hydraulic pressure, a core made of ferromagnetic material and operatively associated to the membrane, and a winding fixed to the casing and operatively coupled to the core to form a variable inductance inductor; wherein a mass is accommodated within the casing and in immediate proximity of said membrane, free to move with respect to the casing in at least one direction corresponding to the axis of the winding.

To improve the characteristics of a portion which can be represented by an approximate first-order line (so-called linearity) in the relation between pressure and diaphragm displacement. To equalize the pressure-applying area/volume of a diaphragm when plural ring-shaped reinforcement ribs are in contact with said cover (no load condition when no pressure is applied to the diaphragm) and the pressure-applying area/volume of a diaphragm when said diaphragm is apart from said cover (the diaphragm is displaced due to pressure load).