The Shand & Jurs 94116 Snap Action Vacuum Breaker permits high capacity atmospheric air flow at low differential pressures to be drawn into the liquid storage tank or pressure vessel when the internal vacuum pressure exceeds the vent setting.
The vent uses a magnetic latch system to hold the seal closed tightly at vacuum levels lower than the setting and at positive pressures. The set point is achieved by the magnetic force of a permanent magnet that attracts a ferrous plate attached to the pallet.
When the tank vacuum pressure reaches the set point, it overcomes the magnetic force and allows the pallet to instantly swing open, providing for 100% opening at set pressure with no overpressure required.
This feature provides greater flow capacities than conventional weight loaded vents.
The 94116 is designed for operation at static pressures up to 1.5 PSIG. Vacuum settings are available from 0.4 to 1.5 inches water column. They are designed for replacement of a rupture disc or in situations where self reclosing, high vacuum capacity is required.
The design incorporates a body that is self-draining and uses a vertical hinged pallet. These features prevent collection of condensates on the seating surface, which can lead to improper functioning of the vacuum vent.