Passive valve assembly

摘要

A passive valve assembly for controlling the flow into or out of chamber (3) through a port (4). The valve assembly comprises a valve element (5) arranged to open in the direction of flow through the port. The valve element (5) has a piston (9) which is reciprocable in a cylinder (10) containing gas. On opening of the valve, gas is compressed in a first chamber (11) of the cylinder (10), and this energy of compression is used to reverse the direction of the valve element (5) and return it to its seat.