| 摘要 |
A football-shaped blockage within a vessel lumen designed to prevent any flow material from passing through the vessel lumen when suction is applied below the blockage or when the flow material pressure is below a given value, and further designed to allow flow when the flow material pressure increases above the given value by allowing the vessel lumen walls to expand around the football-shaped blockage or, alternately, to allow the football-shaped blockage to collapse in response to the increased pressure. A series of compressible members contained within the vessel lumen may also be coupled with the above mentioned blockage device to limit the flow rate beyond the given value. The compressible members are designed to partially restrict flow so as to initially allow for only moderate increases in flow rate with respect to flow material pressure, but with a pressure above a second given material pressure, greater increases in flow rate are allowed. |
