Vents for fluid systems

Abstract

A vent for a fluid system includes a chamber through which fluid can flow along either a first flow path or a second flow path, in which the resistance to fluid flow is relatively high when the fluid follows the first flow path and relatively low when the fluid follows the second flow path. In a preferred embodiment the chamber is substantially cylindrical and has two ports, one of which is substantially coaxial with the chamber and the other of which is substantially tangential to the chamber. The fluid flow, at least when following the first flow path, may include a component of higher density than the fluid, and the flow of the fluid along the first flow path may act to separate the higher density component from the fluid.

1 . A vent for a fluid system, the vent including structure defining a chamber, the chamber defining a first flow path and a second flow path, in which fluid is able to flow through the chamber along either the first flow path or the second flow path, in which the resistance to fluid flow is relatively high when the fluid follows the first flow path and the resistance to fluid flow is relatively low when the fluid follows the second flow path.  
   
   
       2 . A vent as claimed in  claim 1 , in which the first flow path is associated with fluid flow in one direction through the chamber, and the second flow path is associated with fluid flow in the opposite direction through the chamber.  
   
   
       3 . A vent as claimed in  claim 1 , which further includes structure defining two ports, the two ports being in fluid communication with the chamber and lying in planes substantially perpendicular to each other.  
   
   
       4 . A vent as claimed in  claim 3 , in which the chamber is substantially cylindrical.  
   
   
       5 . A vent as claimed in  claim 4 , in which one of the two ports is substantially coaxial with the chamber and the other of the two ports is substantially tangential to the chamber.  
   
   
       6 . A vent as claimed in  claim 5 , in which the inner profile of the substantially tangential port is convergent.  
   
   
       7 . A vent as claimed in  claim 5 , in which the inner profile of the substantially tangential port is convergent-divergent.  
   
   
       8 . A vent as claimed in  claim 5 , in which an annular wall member protrudes generally axially from the coaxial port into the chamber.  
   
   
       9 . A vent as claimed in  claim 1 , in which the fluid flow at least when following the first flow path includes a component of higher density than the fluid and the flow of the fluid along the first flow path acts to separate the higher density component from the fluid.  
   
   
       10 . A vent as claimed in  claim 9 , in which the chamber is extended in an axial direction to receive the higher density component separated from the fluid.  
   
   
       11 . A vent as claimed in  claim 9 , in which means are provided to carry the higher density component out of the chamber.  
   
   
       12 . A vent as claimed in  claim 9 , in which the higher density component comprises a lubricant.  
   
   
       13 . A bearing chamber including a vent as claimed in  claim 1 .  
   
   
       14 . A gas turbine engine including a vent as claimed in  claim 1 .  
   
   
       15 . A venting arrangement for a fluid system, comprising a first vent as claimed in  claim 1  and a second vent as claimed in  claim 1 , the first and second vents being arranged in flow series, in which the first and second vents are so arranged that when fluid flows through the venting arrangement in one direction it follows the first flow path through the chamber of the first vent, and when fluid flows through the venting arrangement in the other, opposite direction it follows the first flow path through the chamber of the second vent.  
   
   
       16 . A venting arrangement for a fluid system, comprising a plurality of vents as claimed in  claim 1 , the vents being arranged in flow series, in which the vents are so arranged that when fluid flows through the venting arrangement in one direction it follows the first flow path through the chamber of each vent in succession, and when fluid flows through the venting arrangement in the other direction it follows the second flow path through the chamber of each vent in succession.  
   
   
       17 . A bearing chamber including a venting arrangement as claimed in  claim 15 .  
   
   
       18 . A bearing chamber including a venting arrangement as claimed in  claim 16 .  
   
   
       19 . A gas turbine engine including a venting arrangement as claimed in  claim 15 .  
   
   
       20 . A gas turbine engine including a venting arrangement as claimed in  claim 16.