1584 results about "Pressure wave" patented technology

An apparatus and methods for performing a circulatory measurement on an extremity, such as a hand, of a subject. The circulatory measurement results in the derivation of an output circulatory metric that may encompass blood pressure or various other circulatory metrics. An indicator of an input circulatory metric at a locus on the extremity is measured, such as a pulse transit time. To determine the pulse transit time, a first plethysmographic signal may be obtained at a first position on the extremity, while a second plethysmographic signal may be obtained at a second position on the extremity of the subject. A transit time characterizing a circulatory pressure wave is calculated based on the first and second plethysmographic signals, leading to derivation of a wave speed. A calibration is then applied to provide the circulatory measurement based at least on the derived wave speed and a measured indicator of a hydrostatic component of blood pressure. Calibration is provided, in certain described embodiments, by derivation of two calibration parameters, a gain and a pulse transit time at zero pressure. Methods for deriving the calibration parameters include performing measurements under distinct hydrostatic pressure conditions, and based upon a measured derivative with respect to pressure of the pulse wave velocity.

A microelectromechanical-acoustic-transducer assembly has: a first die integrating a MEMS sensing structure having a membrane, which has a first surface in fluid communication with a front chamber and a second surface, opposite to the first surface, in fluid communication with a back chamber of the microelectromechanical acoustic transducer, is able to undergo deformation as a function of incident acoustic-pressure waves, and faces a rigid electrode so as to form a variable-capacitance capacitor; a second die, integrating an electronic reading circuit operatively coupled to the MEMS sensing structure and supplying an electrical output signal as a function of the capacitive variation; and a package, housing the first die and the second die and having a base substrate with external electrical contacts. The first and second dice are stacked in the package and directly connected together mechanically and electrically; the package delimits at least one of the front and back chambers.

A method and device for measuring a patient's pulse rate and blood pressure and also the condition of the blood vessel access can be accurately monitored by identifying a frequency component of the pressure wave caused by the patient's heartbeat among other pressure waves in a fluid by frequency analysis. The method and device are used when a medical device is connected to the patient's blood vessel via a blood vessel access and has a mechanical device for applying pressure to a fluid to transport it to said blood vessel.

This disclosure describes systems and methods for purging narrow diameter sensor tubing, occasionally referred to as “sensor lines”, in a ventilation system. The disclosure describes a novel approach in which a series of short, periodic releases of pressurized gas through the sensor tubes are used to clear any blockages due to condensation or patient secretions.

A medical system includes a carrier and a multiplicity of electromechanical transducers mounted to the carrier, the transducers being disposable in effective pressure-wave-transmitting contact with a patient. Energization componentry is operatively connected to a first plurality of the transducers for supplying the same with electrical signals of at least one pre-established ultrasonic frequency to produce first pressure waves in the patient. A control unit is operatively connected to the energization componentry and includes an electronic analyzer operatively connected to a second plurality of the transducers for performing electronic 3D volumetric data acquisition and imaging (which includes determining three-dimensional shapes) of internal tissue structures of the patient by analyzing signals generated by the second plurality of the transducers in response to second pressure waves produced at the internal tissue structures in response to the first pressure waves. The control unit includes phased-array signal processing circuitry for effectuating an electronic scanning of the internal tissue structures which facilitates one-dimensional (vector), 2D (planar), and 3D (volume) data acquisition. The control unit further includes circuitry for defining multiple data gathering apertures and for coherently combining structural data from the respective apertures to increase spatial resolution. When the data gathering apertures are contained in a flexible web or carrier so that the instantaneous positions of the data gathering apertures are unknown, a self-cohering algorithm is used to determine their positions so that coherent aperture combining can be performed.

A method and apparatus for separating a mixture of particles of various sizes in a capillary tube into groups by size using multiple forces of controlled amplitude. Ultrasonic radiation at a first selected frequency is applied to set up a standing pressure wave in the capillary tube, resulting in a first aggregating force which causes particles of all sizes to aggregate at positions within the capillary tube which correspond to nodes or anti-nodes of the standing wave. Transverse vibrations are also applied to the capillary tube. The frequency of the ultrasonic radiation is adjusted to reduce the magnitude of the first aggregating force. Inertial forces resulting from the transverse vibrations then cause the particles to separate by size. The apparatus and method allows a mixture of particles to be separated by size quickly, without requiring the use of high voltages.

A projector (10) for creating electrohydraulic acoustic and pressure waves comprising an energy source (21) (such as a capacitor) within approximately one meter of an electrode array (23). Larger projectors may be formed by arraying the projectors, and still larger projectors by arraying them.

An apparatus for disrupting cells or viruses comprises a container having a chamber for holding the cells or viruses. The container includes at least one flexible wall defining the chamber. The apparatus also includes a transducer for impacting an external surface of the flexible wall to generate pressure waves in the chamber. The apparatus also includes a pressure source for increasing the pressure in the chamber. The pressurization of the chamber ensures effective coupling between the transducer and the flexible wall. The apparatus may also include beads in the chamber for rupturing the cells or viruses.

A pressure wave generator is provided, which has excellent output stability over time. This pressure wave generator comprises a substrate, a heat generating layer, and a heat insulating layer formed between the substrate and the heat generating layer. A pressure wave is generated in a surrounding medium (air) by a change in temperature of the heat generating layer, which is caused upon energization of the heat generating layer. The heat insulating layer comprises a porous layer and a barrier layer formed between the porous layer and the heat generating layer to prevent diffusion of reactive substances such as oxygen and moisture in the air and impurities into the porous layer. By the formation of the barrier layer, it is possible to prevent a reduction in output of the pressure wave generator caused by a change over time of the porous layer.

A system, device and method for dilating an anatomical structure. Systems, devices and methods may comprise a therapeutic component configured to treat a paranasal sinus. Specific embodiments may use high frequency pressure waves and/or cryogenic temperatures.

An apparatus for disrupting cells or viruses comprises a container having a chamber for holding the cells or viruses. The container includes at least one flexible wall defining the chamber. The apparatus also includes a transducer for impacting an external surface of the flexible wall to generate pressure waves in the chamber. The apparatus also includes a pressure source for increasing the pressure in the chamber. The pressurization of the chamber ensures effective coupling between the transducer and the flexible wall. The apparatus may also include beads in the chamber for rupturing the cells or viruses.

A medical assembly is used to deliver a therapeutic substance to a treatment area. The medical assembly comprises a catheter having a distal end and a proximal end, a transducer supported by at least a portion of the distal end of the catheter assembly, and a delivery lumen mounted on the catheter for delivery of a therapeutic substance. Support for the transducer is provided at a preselected number of anchoring points, wherein an inner surface of the transducer is positioned at a preselected distance from an outer surface of the catheter. The preselected distance defines a gap that is occupied by a low density material such as a gas which reflects acoustic pressure waves directed toward the gap by a transducer when a voltage is applied to the transducer. The reflected pressure wave increases the energy in the system, enhancing transport of therapeutic substances from the delivery lumen to the surrounding tissues and/or cells to be treated. The medical assembly may optionally be used in conjunction with both macroporous and microporous balloons. The medical assembly may optionally be modified so that a plurality of transducers are used, wherein the distal end of a transducer is positioned at a preselected distance from the proximal end of an adjacent transducer.

A system that continuously monitors cardiovascular health using an electrocardiography (ECG) source synchronized to an optical (PPG) source, without requiring invasive techniques or ongoing, large-scale external scanning procedures. The system includes an ECG signal source with electrodes contacting the skin, which generates a first set of information, and a watch-like device, worn on a limb such as an arm or a wrist, having a reflectance-based PPG signal source that generates a second set of information. Together with a processing module, housed within the watch-like device and configured to receive and process the first and second sets of information, from which the time differential of the heart beat pulmonary pressure wave can be calculated, continuous data related to cardiovascular health markers such as arterial stiffness can be determined. Automated heart rate calibration of the reflectance-based PPG sensor can also be achieved.

A borehole seismic acquisition system is described with a plurality of sensors arranged so as to identify within the data measured by the pressure sensors P- and S-wave related signals converted at the boundary of the borehole into pressure waves, the sensors being best arranged in groups or clusters sensitive to pressure gradients in one or more directions.

The invention relates to a method for monitoring the supply of substitution liquid during an extracorporeal blood treatment and to an extracorporeal blood treatment unit equipped with a device for monitoring the supply of substitution liquid. The monitoring of the supply of substitution liquid is based on the measurement of pressure waves, which are generated by the substitution liquid pump, in the extracorporeal blood circulation system. A disturbance in the supply of substitution liquid is inferred when the amplitude of the pressure waves exceeds a predetermined limit value. The amplitude of the pressure waves is preferably monitored in the venous blood line.

The invention relates to a hydro-oscillator for well drilling. The hydro-oscillator consists of a hydraulic driving assembly, a fixed valve assembly, a bottom assembly and a vibrating pipe nipple, wherein the vibrating pipe nipple is connected with the hydraulic driving assembly; a rotor is connected with a vibrating valve; the fixed valve assembly is arranged on the bottom assembly; and a power shell is connected with the bottom assembly. A drilling fluid is used for driving the rotor to rotate, and the rotor is used for driving the vibrating valve to vibrate, so that flow holes of the vibrating valve and a fixed valve are staggered with each other, and simple harmonic pressure waves are modulated and are upwardly transmitted to a disc spring for driving the vibrating shell to perform continuous simple harmonic vibration in the axial direction, so that the friction resistance between a drilling column and a well wall is improved effectively, and the drilling speed is increased; and meanwhile, pressure waves are downwardly transmitted to drill bit jet flow, so that periodic change of rock breaking pressure is facilitated, and rocks are crushed effectively. The hydro-oscillator has the characteristics of simple structure, convenience for operating, safety, reliability, low pressure drop, high adaptability, no influence on the drilling tool structure and the like, and plays an important role in increasing the drilling speed and reducing cost.

An acoustic separator comprises: two parallel chamber walls defining a separation chamber therebetween, each chamber wall defining one side of the chamber; inlet means through which fluid can flow into the chamber; and outlet means through which fluid can flow out of the chamber. One of the chamber walls includes a transducer arranged to transmit pressure waves across the chamber towards the other of the chamber walls which in turn is arranged to reflect the pressure waves to set up a standing wave in the chamber. The outlet means defines an opening in one of the sides of the chamber.

A system for distinguishing between a first condition corresponding to a living subject being directly in contact with an object of interest, and a second condition corresponding to the absence of contact between the living subject and the object of interest. A transducer, which may be a MEMs sensor, is disposed in predetermined relationship to the object of interest and produces a transducer signal responsive to a pressure wave resulting from the living subject being directly in contact the object of interest. A database stores data corresponding to the first condition and may contain additional data corresponding to the second condition. A processor calculates an algorithm of a non-linear short-term frequency-selective energy distribution of the transducer signal over time to produce transducer signal data. An arrangement, which may be a human listener or a processor system, determines a threshold between the first and second conditions in response to the transducer signal data and the first and second data. The direct contact may be a tap or stroking contact by a living subject. The transducer can be disposed within, or on the exterior of, the object of interest.

A fusion reactor apparatus for initiating a fusion reaction in a fusionable material is disclosed. The apparatus includes a vessel operable to contain a liquid medium and a vortex generator operable to generate a vortex in the liquid medium. The apparatus also includes a plasma generator operable to generate a magnetized plasma of the fusionable material and to introduce the magnetized plasma into the vortex and a pressure wave generator operably configured to cause a pressure wavefront in the liquid medium to envelope the magnetized plasma and to converge on the magnetized plasma to impart sufficient energy to the fusionable material to initiate fusion in the fusionable material.

A droplet forming flow cytometer system allows high speed processing without the need for high oscillator drive powers through the inclusion of an oscillator or piezoelectric crystal within the nozzle volume and directly coupled to the sheath fluid. The nozzle contain converges so as to amplify unidirectional oscillations which are transmitted as pressure waves through the nozzle volume to the nozzle exit so as to form droplets from the fluid jet. The oscillator is directionally isolated so as to avoid moving the entire nozzle container so as to create only pressure waves within the sheath fluid. A variation in substance concentration is achieved through a movable substance introduction port which is positioned within a convergence zone to vary the relative concentration of substance to sheath fluid while still maintaining optimal laminar flow conditions. This variation may be automatically controlled through a sensor and controller configuration. A replaceable tip design is also provided whereby the ceramic nozzle tip is positioned within an edge insert in the mozzle body so as to smoothly transition from nozzle body to nozzle tip. The nozzle tip is sealed against its outer surface to the nozzle body so it may be removable for cleaning or replacement.