A device for regulating the flow of gas from an environment. The device includes a shell forming a path through which fluid flows. A fixed grate is disposed in the path so that as fluid flows in the path the fixed grate does not move. A movable grate assembly includes one or more plates and a movable...http://www.google.fr/patents/US6688321?utm_source=gb-gplus-shareBrevet US6688321 - Method and apparatus for a flow regulator having an integral hinge
Method and apparatus for a flow regulator having an integral hinge
