Proof testing of mechanical heart valves
First Claim
1. A method of proof testing an assembled mechanical heart valve prosthesis having a valve body and at least one movable occluder, at least one of which has a pyrocarbon surface in which micro crack growth may occur, which method comprises:
- subjecting the assembled valve prosthesis to loading, with the at least one occluder in the closed position, so as to exceed normal service loading on a downstream side of the occluder,acoustically monitoring the valve prosthesis during such loading to detect sounds by measuring transduced voltage signals for such signals whose energy feature exceeds a predetermined acoustic energy level so as to be indicative of crack nucleation and/or incremental crack extension, andrejecting a valve prosthesis where such sounds are detected.
9 Assignments
0 Petitions
Accused Products
Abstract
A method and apparatus for proof testing an assembled mechanical heart valve prosthesis having a valve body and at least one movable occluder wherein at least one of the components has a surface of nonmetallic crystalline material, such as pyrocarbon, in which microcrack growth may occur. The assembled valve prosthesis is subjected to fluid loading with the occluder in the closed position so as to create omnidirectional pressure of at least 20 psig therewithin on the downstream side of the occluder. During fluid loading of the assembled valve, acoustic monitoring is carried out using a transducer to detect sounds that are indicative of crack nucleation and/or incremental crack extension, based upon a predetermined fail-pass criterion. Any valve prosthesis wherein sounds of a greater magnitude are detected is rejected.
-
Citations
20 Claims
-
1. A method of proof testing an assembled mechanical heart valve prosthesis having a valve body and at least one movable occluder, at least one of which has a pyrocarbon surface in which micro crack growth may occur, which method comprises:
-
subjecting the assembled valve prosthesis to loading, with the at least one occluder in the closed position, so as to exceed normal service loading on a downstream side of the occluder, acoustically monitoring the valve prosthesis during such loading to detect sounds by measuring transduced voltage signals for such signals whose energy feature exceeds a predetermined acoustic energy level so as to be indicative of crack nucleation and/or incremental crack extension, and rejecting a valve prosthesis where such sounds are detected. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. A method of proof testing an assembled mechanical heart valve prosthesis having a pyrocarbon valve body and at least one pyrocarbon movable occluder, which method comprises:
-
subjecting the assembled valve prosthesis to fluid-loading with the at least one occluder in the closed position so as to create omnidirectional pressure of at least about 10 psig therewithin on a downstream side of the occluder, acoustically monitoring the valve prosthesis during such fluid-loading by directly or indirectly coupling the valve body with a transducer that includes a piezoelectric element so as to detect broadband wavelength sounds, and rejecting a valve prosthesis where sounds are detected in the form of voltage signals whose amplitude feature exceeds a predetermined amplitude that is indicative of crack nucleation and/or incremental crack extension in pyrocarbon. - View Dependent Claims (18, 19)
-
-
10. Apparatus for proof testing an assembled mechanical heart valve prosthesis having a valve body and at least one movable occluder, at least one of which assembled components has a surface that is formed of a material in which microcrack growth may occur, which apparatus comprises:
-
a fixture for holding the valve body of the assembled valve prosthesis with the at least one movable occluder in the closed position, acoustic sensing means which includes a waveguide and transducer means that are adapted to detect sound emitted from said assembled components and generate a responsive electrical signal, spring-biasing means connected to said waveguide which causes said waveguide to seat in close contact with an exterior surface of the valve body being tested, means for fluid-loading an interior region of said assembled valve prosthesis at a location downstream of said closed occluder so as to apply omnidirectional pressure therewithin of at least about 10 psig, and means for monitoring output signals from said transducer means during fluid-loading of said interior region of the valve prosthesis to detect signals resulting from sounds being emitted that are indicative of crack nucleation and/or incremental crack extension in the assembled valve prosthesis. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 20)
-
Specification