Abstract: A diaphragm valve for shutting off milk flow through a claw (13) of a vacuum driven milking machine has, in a preferred embodiment, a lever (5) linked (6), outside the milk flow, to the diaphragm (4), thereby avoiding any bushings which are prone to leakage. The lever (5) can be swung manually to a position holding the diaphragm away from its seat thereby permitting milk flow. In the automatically closing embodiments, the lever is swung in this case against the bias of a spring (7) and is retained in this open position if the suction force acting on the diaphragm (4) and the link (6) is sufficient to overcome the bias of the spring (7), which will be the case when there is normal milk flow through the valve.