Ventilation system

Abstract

A backdraft damper for a ventilation fan assembly, the backdraft damper having a main body having a wall defining an inner surface, an outer surface, a first open end and a second open end. An interior space is defined by the main body wall inner surface. A damper door is rotationally coupled to the main body wall and located within the interior space. The damper door defines a perimeter edge and the damper door is configured to rotate between (i) a closed position, in which the perimeter edge is located adjacent to the main body inner surface, and (ii) an open position in which a majority of the perimeter edge is not adjacent to the main body inner surface. A block extends from the main body wall inner surface into the interior space adjacent to the damper door perimeter edge when the damper door is in the closed position and, during operation of the fan assembly, creates an area of high pressure which creates a torque on the damper door.

1 . A ventilation fan assembly comprising:
 a housing having at least one sidewall defining an interior space, an inlet opening into the interior space, and an outlet aperture spaced apart from the inlet, wherein the housing is configured to contain a blower assembly in the interior space;   a backdraft damper configured to be coupled to the housing adjacent to the outlet aperture, the backdraft damper comprising,
 a main body having a wall defining an inner surface, an outer surface, a first open end and a second open end;
 an interior space defined by the main body wall inner surface; 
 
 a damper door rotationally coupled to the main body wall and located within the interior space;
 the damper door defining a perimeter edge and configured to rotate between (i) a closed position, in which the perimeter edge is located adjacent to the main body inner surface, and (ii) an open position in which a majority of the perimeter edge is not adjacent to the main body inner surface; 
 wherein the damper door is rotationally biased to the closed position; 
 
 a block extending from the main body wall inner surface into the interior space adjacent to the damper door perimeter edge when the damper door is in the closed position. 
   
     
     
         2 . The ventilation fan of  claim 1 , wherein the block is located at the gravitational bottom of the main body wall inner surface. 
     
     
         3 . The ventilation fan of  claim 1 , wherein the block is configured to create an area of high pressure when air flows through the interior space. 
     
     
         4 . The ventilation fan of  claim 3 , wherein the area of high pressure creates a torque on the damper door opposite of a torque created by gravity. 
     
     
         5 . The ventilation fan of  claim 1 , where the block defines a rectangular cross section. 
     
     
         6 . The ventilation fan of  claim 1 , wherein the block is constructed of a rigid, closed cell foam. 
     
     
         7 . The ventilation fan of  claim 1 , wherein the block is constructed of a non-rigid material. 
     
     
         8 . A backdraft damper for a ventilation fan assembly, the backdraft damper comprising:
 a main body having a wall defining an inner surface, an outer surface, a first open end and a second open end;
 an interior space defined by the main body wall inner surface; 
   a damper door rotationally coupled to the main body wall and located within the interior space;
 the damper door defining a perimeter edge and configured to rotate between (i) a closed position, in which the perimeter edge is located adjacent to the main body inner surface, and (ii) an open position in which a majority of the perimeter edge is not adjacent to the main body inner surface; 
 wherein the damper door is rotationally biased to the closed position; 
   a block extending from the main body wall inner surface into the interior space adjacent to the damper door perimeter edge when the damper door is in the closed position.   
     
     
         9 . The backdraft damper of  claim 8 , wherein the block is located at the gravitational bottom of the main body wall inner surface. 
     
     
         10 . The backdraft damper of  claim 8 , wherein the block is configured to create an area of high pressure when air flows through the interior space. 
     
     
         11 . The backdraft damper of  claim 10 , wherein the area of high pressure creates a torque on the damper door opposite of a torque created by gravity.