DIAPHRAGM VALVE
A fluid valve assembly has a valve body (10, 50) which defines a valve chamber (16, 48) and has inlet and outlet ports (12, 14, 38, 46). A resilient valve member (20, 40) lies within the valve chamber. In one embodiment, the member has a conical end section (28) which may be stretched to fit into a correspondingly tapered valve seat (19). In an alternative embodiment, the member (40) may also define one of the ports (38) and can be bent against a valve seat (53) to stop fluid flow. Either embodiment may, alternatively, be biased closed, deformation of the member then opening the valve. The invention minimises the amount of dead space in the valve, thus reducing reading errors due to retention of fluid in this space. Compared with pinch valves, actuation force is also reduced.