| 摘要 |
The valve has two shutters arranged on an internal peripheral surface of an annular support. Each shutter has a central part organized in a symmetrical manner by side wings, where the wings respectively permit rotation of the shutters with internal surfaces of articular extensions (32, 34) by terminal portions of the wings. Articulation facets of the portions are respectively supported against portions of the internal surfaces when the shutters are open, and totalize a surface lower than 5 percentage of total exterior surface of the shutters. |
