Patent ID: 11946376
Assignee: FLOODBREAK L.L.C.
Field: Civil engineering (Other fields)
Classification: CPC E  F | IPC E

Claim 0:
1. Apparatus for preventing downward flow of ground surface water into an underground ventilation duct fluidly communicating through a vertical ventilation shaft to an atmospheric opening of the shaft while maintaining atmospheric ventilation to said underground ventilation duct, comprising:
a) a support for suspension within the ventilation shaft from a top thereof, said support having
1) a vertical outer wall having an exterior adjacent said ventilation shaft, an interior of said outer wall having a top opening to the atmosphere,
2) a vertical inner wall having an exterior spaced from said interior of said outer wall and an interior defining a ventilation passageway having top and bottom openings for fluid communication between atmosphere and said ventilation shaft,
3) a floor connecting a bottom of said outer wall and a bottom of said inner wall of said support,
the spacing between the exterior of said inner wall and the interior of said outer wall forming a vertical chamber over said floor for receipt of ground surface water entering from said top opening of the outer wall;

b) a grating covering said ventilation passageway allowing fluid communication between atmosphere and said ventilation passageway; and
c) a buoyant float housed within said chamber and having inner and outer surfaces respectively adjacent said exterior of said inner wall and said interior of said outer wall, said float being sufficiently spaced above said floor that ground surface water entering said chamber from said top opening of said outer wall can flow under said float and buoy the float upwardly in said chamber, rise of water in the chamber elevating the float above ground, blocking surface water from entering the ventilation passageway through said grating, said ventilation passageway of said support remaining open to atmosphere.