Flow Sensor Valves eliminate the problem of vacuum loss through non-working standard cups or valved cups. These are manifolded or located in-line rather than at the suction cup. It has spring-loaded actuation, Bleed vent and Slotted poppet to improve performance. It is tested for proper operation and is helium leak tested at the envelope to a maximum leak rate of 4 x 10-9 std cm3/s.