摘要 |
<p>A fluid flow regulation system (2) comprises an inlet (4); an outlet (6); and an adjustable flow regulation means (10) connected between the inlet (4) and the outlet (6). The regulation means (10) has a closed position (22) at which a leakage gas flow through the system is established. An extraction device (12) is provided for fluid connection with one or both of the inlet (4) and the outlet (6) and is operable to extract fluid to provide at a zero or negative flow from the outlet (6) when the flow regulation means (10) is in the closed position (22). <IMAGE></p> |