Abstract: A fluidized bed pyrolytic carbon coating apparatus (1) is provided for coating substrate surfaces with pyrolytic carbon. The preferred coating apparatus (1) includes a fluidized bed reactor (10) having a reactor chamber (22), a gas feed inlet (24), an exhaust gas outlet (26), a source (12) of process feed gas and a gas line (14) through which the process feed gas can pass from the source (12) of process feed gas to the gas feed inlet (24) and into the reactor chamber (22). The gas line (14) includes an actuator (20) having a timing circuit (37) which acts to vary a rate of flow of process feed gas through the gas line (14) into the reactor chamber (22) such that the rate of flow into the reactor chamber (22), cycles regularly and consistently over a period of time so as to create a pulsating gas flow and a pulsation effect upon the fluidized bed within the reactor chamber (22).

Abstract: A bileaflet heart valve comprising an annular base and pivoting leaflets. Each leaflet is “free-floating” within recesses without fixed rotational axis in order to increase translational movement and redistribute stresses. Each recess fluidly communicates with a groove extending at least partially around the inner surface of the annular base and fluid flow is directed through the recesses at different angles during antegrade circulation, retograde circulation, and valve closure. A recess entrance angle to each of the recesses in certain embodiments is preferably less than about 35° and the pivoting mechanism within each recess includes first and second fulcrum edges of each leaflet shiftably engaged with side surfaces of the respective recesses. The leaflets have a beveled bottom side having two separate planar surfaces which lie at an angle to one another.

Abstract: A bileaflet heart valve comprising an annular base and pivoting leaflets. Each leaflet is “free-floating” within recesses without fixed rotational axis in order to increase translational movement and redistribute stresses. Each recess fluidly communicates with a groove extending at least partially around the inner surface of the annular base and fluid flow is directed through the recesses at different angles during antegrade circulation, retrograde circulation, and valve closure. A recess entrance angle to each of the recesses preferably being less than about 35° and the pivoting mechanism within the recess including first and second fulcrum edges of each leaflet shiftably engaged with side surfaces of the respective recesses. The leaflets have a beveled bottom side having two separate planar surfaces which lie at an angle to one another.

Abstract: A bileaflet heart valve comprising an annular base and pivoting leaflets. Each leaflet if "free-floating" within recesses without fixed rotational axis, to increase translational movement and redistribute stresses. Each recess fluidly communicates with a groove extending at least partially around the inner surface of the annular base and flow is directed through the recesses at different angles during antegrade circulation, retrograde circulation, and valve closure. A recess entrance angle to each of the recesses preferably being less than about 35.degree. and the pivoting mechanism within the recess including first and second fulcrum edges of each leaflet shiftably engaged with side surfaces of the respective recess. The leaflets have a beveled bottom surface having two separate planar surfaces which lie at an angle to one another. In preferred embodiments, a central region of each leaflet is spaced apart from the annular base when the leaflet is in a fully closed position to minimize cavitation.