Washington University

Other

Albany International Corporation

Dynatek, Inc.

Wilbur M Swanson

John Skelton

Robert B Davis

Richard E Clark

Apparatus and methods for durability (fatigue) testing of prosthetic heart valves or other check valves. The apparatus is circular in plan and includes a test fixture in which the valves are circularly arranged, located with communicating passages, such passages communicating with bellows closed at one end. The bellows are carried by a swash plate journalled to a motor by a coupling providing an adjustable tilt axis. The tilt axis determines the amplitude of the motion or flow of the fluid, as the bellows alternately expand and contract. A central bypass chamber includes orifices which are selectively varied in effective cross section to control an amount of the test fluid which bypasses the test samples, thereby determining fluid pressure differential across the sample valves. Fluid in the apparatus can be heated by an electric heater to temperatures similar to human blood, a temperature probe monitoring the temperature for its control. A pressure tap monitors the fluid pressure for shutting down the apparatus if abnormal pressures or leaks are developed. Several prosthetic heart valves, e.g., two, four, six, eight, etc., are held by the fixture at the same time for life testing at relatively high cyclic rates.

Accelerated heart valve testing apparatus and methods

Apparatus and methods for durability (fatigue) testing of various samples (materials, valves, components and other objects) involves use of a test fixture for clamping a sample to be tested in a closed fluid environment and providing fluid passages on opposite sides of the object to be tested through which a bellows-actuated fluid oscillator causes axial oscillating flow of fluid, causing the sample to undergo repeated bidirectional axial pressures producing flexing in the case of a membrane of elastic material or repeated closing and opening in the case of a valve, etc., in response to oscillation of the fluid in the passages. The device is particularly suited for 'blister testing' of elastomers and for life testing of prosthetic heart valves and other valves.

Fluid oscillation materials testing apparatus and methods

A frame system for heart valve prosthesis. A first frame has at least three generally parallel legs each comprising a pair of rod portions connected at one end and diverging at the other end as lobes respectively connecting with rod portions of others of said legs. The lobes form an aperture therebetween and the legs are adapted to receive the margin of a valve leaflet between the rod portions thereof. Thus, the leaflet may be secured to two adjacent legs and the interconnecting lobe so as to have a free edge extending between said adjacent legs. A second frame is adapted to nest with the first frame and comprises a rod formed to be substantially congruent with the interconnecting lobes, whereby the leaflets may be secured to and between the frames.

Heart valve prosthesis

A carburetor which comprises a casing, an air inlet at the upper end thereof and an air-fuel mixture discharge at the lower end thereof, with a venturi throat located downwardly of said inlet, a sonic throat below said venturi throat, and a diffuser section interconnecting the sonic throat and the discharge. Portions of the wall of the sonic throat are provided with a plurality of indentations, projections, or surface irregularities for stabilizing the flow therethrough and conducing to the uniformity of the air-fuel mixture. At least one portion of said sonic throat is movable with respect to the fixed portions of said throat for altering the cross-section thereof responsive to fuel requirements for combustion.

Carburetor

A prosthesis for an inadequate or diseased heart valve, the prosthesis being formed of a porous fabric comprising multifilament synthetic yarns supported on a plural-lobed frame. The frame has generally parallel legs each comprising a pair of rod portions. The fabric is inserted between the rod portions of the legs to form flexible leaflets. Each leaflet consists essentially of a textile of filaments having a substantial number of open interstitial spaces in the range of 20 to 40 microns evenly distributed throughout the fabric. The resulting composite structures are free of thrombogenic complications.

A carburetor which comprises a casing, an air inlet at the upper end thereof and an air-fuel mixture discharge at the lower end thereof, with a venturi throat located downwardly of said inlet, a sonic throat below said venturi throat, and a diffuser section interconnecting the sonic throat and the discharge. Portions of the wall of the sonic throat are provided with a plurality of indentations, projections, or surface irregularities for stabilizing the flow therethrough and conducing to the uniformity of the air-fuel mixture. At least one portion of said sonic throat is movable with respect to the fixed portions of said throat for altering the cross-section thereof responsive to fuel requirements for combustion. One form of the invention embodies a plug vertically shiftable by a control shaft, having a fuel chamber with emission ports to the interior of the casing whereby said plug acts as an accelerator pump.

Growing community of inventors

St. Louis County, MO, United States of America

Wilbur M Swanson