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

Claim 18:
19. 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, said floor surrounding said ventilation passageway,
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;
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; and
d) one or more stops located on said exterior of said inner wall of said support, said float having a companion member for each stop which said stop can contact to prevent rise of said float out of said support,
e) a gasket affixed either to a recess in said inner surface of said float or to an upper extent of said exterior of inner wall of said support to seal against said inner surface of said float to prevent water entering said chamber from said opening at the top of said outer wall from escaping from said chamber;
f) a drain located in said floor of said support;
g) said top of said ventilation shaft having an inset ledge and an upper extent said outer wall of said support having transverse flanges for laying over said inset ledge to hang said support in said shaft.