Vent valve

An container assembly comprising:

• a container;
• and
• a vent valve connected to said container, said vent valve comprising at least:
• a housing a portion of which is interengaged with said container, and having at least one axis and at least one aperture;
• a first poppet axially movably within said housing between a first closed position and a first open position;
• a second poppet axially movable within said first poppet between a second closed position and a second open position;
• a first seal between said first poppet and said housing;
• a second seal between said first poppet and said second poppet;
• a first resilient member disposed within a first space between said housing and said first poppet, and having a resilient force sufficient to hold said first poppet in said first closed position such that said first poppet urges said first seal against said housing when a pressure differential axially across said first poppet is below a first point, and to allow said first poppet to move in said first direction to said first open position when said fluid pressure differential exceeds said first point;
• and
• a second resilient member disposed within a second space between said first poppet and said second poppet, and having a resilient force sufficient to hold said second poppet in said closed position such that that said second poppet urges said second seal against said first poppet when a pressure differential axially across said second poppet is below a second point, and to allow said second poppet to move in a second direction, different from said first direction, to said second open position when said pressure differential exceeds said second point.