Jentek Sensors, Incorporated

Scimed Life Systems, Inc.

Boston Scientific Corporation

Vladimir B Tsukernik

Neil J Goldfine

Andrew P Washabaugh

Darrell E Schlicker

Vladimir A Zilberstein

David C Grundy

Ian C Shay

Robert J Lyons

Mark D Windoloski

Karen E Walrath

Sheng-ping Zhong

Charles L Euteneuer

William Joseph Shaw

Christopher R Larson

Yanko K Sheiretov

Todd M Dunford

Terry V Brown

Christopher A Craven

Volker Weiss

John W Humphrey

Leo M Klisch

Nam H Hoang

David C Clark

Jonathan C Sell

Christopher Root

William M Chepolis

Lawrence W Ulanowski

James M Fisher

Ian C Shav

Eric Hill

Described are methods for monitoring of stresses and other material properties. These methods use measurements of effective electrical properties, such as magnetic permeability and electrical conductivity, to infer the state of the test material, such as the stress, temperature, or overload condition. The sensors, which can be single element sensors or sensor arrays, can be used to periodically inspect selected locations, mounted to the test material, or scanned over the test material to generate two-dimensional images of the material properties. Magnetic field or eddy current based inductive and giant magnetoresistive sensors may be used on magnetizable and/or conducting materials, while capacitive sensors can be used for dielectric materials. Methods are also described for the use of state-sensitive layers to determine the state of materials of interest. These methods allow the weight of articles, such as aircraft, to be determined.

Magnetic field characterization of stresses and properties in materials

Eddy current sensors and sensor arrays are used for process quality and material condition assessment of conducting materials. In an embodiment, changes in spatially registered high resolution images taken before and after cold work processing reflect the quality of the process, such as intensity and coverage. These images also permit the suppression or removal of local outlier variations. Anisotropy in a material property, such as magnetic permeability or electrical conductivity, can be intentionally introduced and used to assess material condition resulting from an operation, such as a cold work or heat treatment. The anisotropy is determined by sensors that provide directional property measurements. The sensor directionality arises from constructs that use a linear conducting drive segment to impose the magnetic field in a test material. Maintaining the orientation of this drive segment, and associated sense elements, relative to a material edge provides enhanced sensitivity for crack detection at edges.

Material condition assessment with eddy current sensors

Methods and apparatus are described for absolute electrical property measurement of materials. This is accomplished with magnetic and electric field based sensors and sensor array geometries that can be modeled accurately and with impedance instrumentation that permits accurate measurements of the in-phase and quadrature phase signal components. A dithering calibration method is also described which allows the measurement to account for background material noise variations. Methods are also described for accounting for noise factors in sensor design and selection of the optimal operating conditions which can minimize the error bounds for material property estimates. Example application of these methods to automated engine disk slot inspection and assessment of the mechanical condition of dielectric materials are presented.

Absolute property measurements using electromagnetic sensors

Methods are described for the use of conformable eddy-current sensors and sensor arrays for characterizing residual stresses and applied loads in materials. In addition, for magnetizable materials such as steels, these methods can be used to determine carbide content and to inspect for grinding burn damage. The sensor arrays can be mounted inside or scanned across the inner surface of test articles and hollow fasteners to monitor stress distributions. A technique for placing eddy-current coils around magnetizable fasteners for load distribution monitoring is also disclosed.

Applied and residual stress measurements using magnetic field sensors

Combined wound and micro-fabricated winding constructs are described for the inspection of materials and the detection and characterization of hidden features or flaws. These constructs can be configured as sensors or sensor arrays that are surface mounted or scanned over conducting and/or magnetizable test materials. The well-defined geometry obtained micro-fabricated windings and from carefully wound coils with known winding positions permits the use of model based inversions of sensed responses into material properties. In a preferred embodiment, the primary winding is a wound coil and the sense elements are etched or printed. The drive or sense windings can also be mounted under fasteners to improve sensitivity to hidden flaws. Ferrites and other means may be used to guide the magnetic flux and enhance the magnetic field in the test material.

Hybrid wound/etched winding constructs for scanning and monitoring

A set of curved components, such as the dovetail region of engine blades, are inspected by mounting each component into a circular carousel in a vertical orientation and rotating the carousel to move each component toward and away from an inspection site. The inspection site clamps a flexible eddy current sensor array to the curved material surface, scans the array over the surface, records the sensor position. A rigid element having a surface geometry similar to the surface shape of the component can be attached to the component to facilitate scanning of the sensor array over a component edge. The response of each sense element in the array may be converted into an effective material property and sense element proximity to the component material surface to verify the quality of the inspection scan and the presence of a defect such as a crack.

Engine blade dovetail inspection

Described are methods for pressurizing elastic support structures or balloons in sensor probes used for the inspection of components having areas of limited access. When inflated, the balloons press flexible sensors against the surface of the material under test. When deflated, the balloons permit easier insertion of the probes into the component and reduce the mechanical stresses on the sensors, thereby extending the sensor lifetime. By sequentially partially inserting the sensor into a limited access area from either side of the limited access area and scanning in opposite directions, the entire surface of the test material can be inspected.

Method for inspecting a channel using a flexible sensor

Material condition monitoring may be performed by electromagnetic sensors and sensor arrays mounted to the material surface. The sensors typically have a periodic winding or electrode structure that creates a periodic sensing field when driven by an electrical signal. The sensors can be thin and flexible so that they conform to the surface of the test material. They can also be mounted such that they do not significantly modify the environmental exposure conditions for the test material, such as by creating stand-off gaps between the sensor and material surface or by perforating the sensor substrate.

Method for material property monitoring with perforated, surface mounted sensors

A thrombus filter configured for placement in within a blood vessel lumen defined by a blood vessel wall. Methods and devices for selectively removing the thrombus filter when the presence of a filter in the vascular system is no longer desired. The thrombus filter includes a first strand formation, a second strand formation, and a joined portion.

Intravascular filter retrieval device and method

Inductive sensors measure the near surface properties of conducting and magnetic material. A sensor may have primary windings with parallel extended winding segments to impose a spatially periodic magnetic field in a test material. Those extended portions may be formed by adjacent portions of individual drive coils. Sensing elements provided every other half wavelength may be connected together in series while the sensing elements in adjacent half wavelengths are spatially offset. Certain sensors include circular segments which create a circularly symmetric magnetic field that is periodic in the radial direction. Such sensors are particularly adapted to surround fasteners to detect cracks and can be mounted beneath a fastener head. In another sensor, sensing windings are offset along the length of parallel winding segments to provide material measurements over different locations when the circuit is scanned over the test material. The distance from the sensing elements to the ends of the primary winding may be kept constant as the offset space in between sensing elements is varied. An image of the material properties can be provided as the sensor is scanned across the material.

Surface mounted and scanning spatially periodic eddy-current sensor arrays

Pressurized elastic support structures or balloons are used to press flexible sensors against the surface a material under test. Rigid support elements can also be incorporated into the inspection devices to maintain the basic shape of the inspection structure and to facilitate positioning of the sensors near the test material surface. The rigid supports can have the approximate shape of the test material surface or the pressurization of one or more balloons can be used to conform the sensor to the shape of the test material surface.

Fluid supports for sensors

A system for controlling delivery of a physiological fluid internally to a patient from a balloon catheter. The system includes a controller, an inflation-fluid pressurizer for maintaining inflation fluid in an inflation-fluid conduit under pressure, and a physiological-fluid pressurizer for maintaining physiological fluid in a physiological-fluid conduit under pressure. The inflation-fluid pressurizer is connected to receive signals from the controller to cycle pressure in the inflation-fluid conduit between a balloon inflating pressure and a balloon deflating pressure. The physiological-fluid pressurizer is connected to receive signals from the controller to cycle pressure in the physiological-fluid conduit between a fluid delivery pressure and a resting pressure. The controller is programmed to synchronize signals to the inflation-fluid pressurizer with signals to the physiological-fluid pressurizer. Thus, periods of balloon inflating pressure in the inflation-fluid conduit generally overlap with periods of fluid delivery pressure in the physiological-fluid conduit, and periods of balloon deflating pressure in the inflation-fluid conduit generally overlap with periods of resting pressure in the physiological-fluid conduit.

Drug delivery system

Devices and methods for applying a polymeric coating to a medical device. The steps of the coating process including applying a liquid polymeric material to the surface of the medical device, then directing a stream of gas to impinge on the surface of the medical device. Excess liquid polymeric material is removed from the surface of the medical device. The devices used in the coating process and the coated medical device are also part of this invention.

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West Roxbury, MA, United States of America

Vladimir B Tsukernik