Non-return valve

摘要

A valve (10) having a port (25) defined by a plurality of lips (30,31) each lip comprising elongate inner and outer portions (30a,31a,30b,31b) linked by an elongate sealing portion, wherein a lip is resiliently deformable from a first position in which the port (25) is closed by engagement of the sealing portions with one another to a second position in which the port is open, the valve being characterised in that the inner portion (30a,31a) of the deformable lip is bowed in inwardly along its long axis. <IMAGE>