NON-RETURN VALVE

摘要

A self-acting fluid non-return valve (e.g. a prosthetic heart valve) comprises a flap member located in a smooth bored passage to turn about a pivoting axis between closed and open positions under the influence of pulsing fluid flow through the passage. The pivoting axis divides the flap member into major and minor areas, the former of which is downstream of the axis when the flap member is open to fluid flow. The movement of the flap member is caused by an aerofoil shaping of the flap member which is localized to a part only of the major area.