Weir diaphragm valve

Weir diaphragm valve—has a weir located in the body of the valve. Flow must go over the top of the weir and lift the compressor to exit. There is a large pressure drop across the body of the valve. This valve uses thicker, more durable diaphragm material. 

Fig. 8 Weir-style diaphragm valves shutoff and point-of-use configurations. (Courtesy of ITT Industries.)...

Diaphragm valves (Fig. 8.35) consist of a straight PFA tube with a weir on which a PTFE diaphragm with a rubber backing is clamped down to control or stop the flow. These valves are available in sizes up to 8" (20 cm). 

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