Cowl for a ventilation system

Abstract

A cowl for a ventilation system is provided that includes at least two separate flow paths, an outlet flow path defined by a first conduit and an inlet flow path defined by a second conduit that extends around the first conduit of the outlet flow path, the first and second conduits extending in the direction of a common axis, the inlet and outlet flow paths each having a first end adapted to open to atmosphere and each having a second end adapted to be connected to the ventilation system. The inlet flow path includes a mouth portion at its first end, the mouth portion substantially facing a direction perpendicular to the common axis to provide an opening into the inlet flow path and including at least one louver, the louver configured to present to incoming air a radially outward upwardly inclined section and a radially inward downwardly inclined section.

What is claimed is: 
     
         1 . A cowl for a ventilation system comprising:
 at least two separate flow paths, the at least two separate flow paths including an outlet flow path defined by a first conduit and an inlet flow path defined by a second conduit that extends around the first conduit of the outlet flow path,   the first and second conduits extending along a common axis, the inlet and outlet flow paths each having a first end adapted to open to atmosphere and each having a second end adapted to be connected to the ventilation system, wherein   the inlet flow path includes a mouth portion at the first end, the mouth portion facing a direction perpendicular to the common axis to provide an opening into the inlet flow path and including at least one louver, the louver configured to present to incoming air a radially outward upwardly inclined section and a radially inward downwardly inclined section.   
     
     
         2 . A cowl according to  claim 1 , wherein the mouth extends above a terminal end of the second conduit and a guide section is arranged to extend out of the second conduit and define the mouth portion with the terminal end of the second conduit. 
     
     
         3 . A cowl according to  claim 2 , wherein the first conduit forms the guide section. 
     
     
         4 . A cowl according to  claim 2 , wherein the guide section presents a smooth surface facing the mouth portion for guiding air between the mouth portion and the first end of the second conduit. 
     
     
         5 . A cowl according to  claim 2 , wherein the terminal end of the second conduit is flared radially outwardly. 
     
     
         6 . A cowl according to  claim 1 , wherein the mouth portion includes a plurality of louvers arranged in a stacked configuration. 
     
     
         7 . A cowl according to  claim 6 , wherein the plurality of louvers having adjacent louvers that define a flow path through the mouth portion into the inlet flow path that extends upwardly and then downwardly. 
     
     
         8 . A cowl according to  claim 1 , wherein the inlet flow path, at least at the mouth portion, includes at least two sectorial fins extending in a radial direction configured to divide the mouth portion into at least two sectors facing in different radial directions. 
     
     
         9 . A cowl according to  claim 8 , further comprising a separator flange extends radially outwardly and downwardly. 
     
     
         10 . A cowl according to  claim 8 , further comprising a separator flange that includes a guide surface that extends radially inwardly from a lower surface thereof, the guide surface being complimentary to an upper-most louver of the mouth portion. 
     
     
         11 . A cowl according to  claim 1 , further comprising a separator flange that extends radially outwardly at a terminal end of the first conduit, the separator flange defining an upper wall of the mouth portion and a lower wall of an opening to the outlet flow path. 
     
     
         12 . A cowl according to  claim 1 , further comprising a cap that extends over and is spaced from the first end of the outlet flow path. 
     
     
         13 . A cowl according to  claim 12 , further comprising a separator flange, wherein the cap has a rim, wherein the rim and the separator flange define an opening from a void within the cap, the first conduit opening into the void, and wherein the separator flange extends radially outwardly at a terminal end of the first conduit. 
     
     
         14 . A cowl according to  claim 12 , wherein the cap includes at least two sectorial fins extending in a radial direction configured to divide an opening in the cap into at least two sectors facing in different radial directions. 
     
     
         15 . A cowl according to  claim 1 , wherein the inlet flow path is annular and extends around the outlet flow path, the first and second conduits arranged coaxially along the common axis. 
     
     
         16 . A passive ventilation system for a building including an inlet conduit for delivering atmospheric air into the building and an outlet conduit for exhausting air from the building to atmosphere, the system further including the cowl of  claim 1 , wherein the outlet conduit is connected to the second end of the outlet flow path and the inlet conduit is connected to the second end of the inlet flow path. 
     
     
         17 . A cowl for a ventilation system comprising:
 at least two separate flow paths, the at least two separate flow paths including an outlet flow path defined by a first conduit and an inlet flow path defined by a second conduit that extends around the first conduit of the outlet flow path,   the first and second conduits extending in the direction of a common axis, the inlet and outlet flow paths each having a first end open to atmosphere and each having a second end adapted to be connected to the ventilation system, wherein   a separator flange extends radially outwardly at a terminal end of the first conduit to separate atmospheric air flow, the separator flange having a lower surface configured to guide laterally flowing atmospheric air downwardly into the inlet flow path, and an upper surface configured to guide laterally flowing atmospheric air upward and over the open end of the outlet flow path.   
     
     
         18 . A cowl for a ventilation system comprising:
 at least two separate flow paths, the at least two separate flow paths including an outlet flow path defined by a first conduit and an inlet flow path defined by a second conduit that extends around the first conduit of the outlet flow path,   the first and second conduits extending in the direction of a common axis, the inlet and outlet flow paths each having a first end open to atmosphere and each having a second end adapted to be connected to the ventilation system, wherein   the cowl includes a cap, the cap extending over and spaced from the open end of the first conduit and having a rim arranged lower than the open end.   
     
     
         19 . A cowl for a ventilation system comprising:
 at least two separate flow paths, the at least two separate flow paths including an outlet flow path defined by a first conduit and an inlet flow path defined by a second conduit that extends around the first conduit of the outlet flow path,   the first and second conduits extending in the direction of a common axis, the inlet and outlet flow paths each having a first end open to atmosphere and each having a second end adapted to be connected to the ventilation system, wherein   the cowl includes a cap, the cap extending over and spaced from the open end of the first conduit and wherein the cap includes a plurality of radially extending sectorial fins arranged to channel air towards a central axis.   
     
     
         20 . A cowl for a ventilation system comprising:
 at least two separate flow paths, the at least two separate flow paths including an outlet flow path defined by a first conduit and an inlet flow path defined by a second conduit that extends around the first conduit of the outlet flow path,   the first and second conduits extending in the direction of a common axis, the inlet and outlet flow paths each having a first end adapted to open to atmosphere and each having a second end adapted to be connected to the ventilation system, wherein   the inlet flow path includes a mouth portion at the first end, the mouth portion facing a direction perpendicular to the common axis to provide an opening into the inlet flow path, the mouth portion defined between the first end of the inlet flow path and a terminal end of a guide portion that extends out of the inlet flow path, the guide portion having a necked portion opposite the mouth portion.