Damper for Positive Pressure Air Cleaner

Abstract

The invention is a damper that closes off supply duct air when the unit is off to prevent air from exiting through the outlet, and opens when the unit is on to allow room air and/or supply duct air to exit through an outlet. The damper may be either motorized or mechanically biased.

What is claimed is: 
     
         1 . A positive pressure air purification system comprising:
 a housing having:
 a room air inlet configured to fluidly receive air from a room where the air purification system resides; 
 a supply duct inlet configured to fluidly receive air from a source other than the room where the air purification system resides; and 
 a outlet configured to expel air into the room; and 
   a first damper configured to:
 (1) always allow air to pass from said supply duct inlet through said housing to said outlet; and 
 (2) selectively allow or disallow room air to pass from said room air inlet through said housing to said outlet. 
   
     
     
         2 . The air purification system of  claim 1 , wherein said first dampener has a first position which allows air from said supply duct inlet to pass from said supply duct inlet through said housing to said outlet. 
     
     
         3 . The air purification system of  claim 1 , wherein said first position prevents air from said room air inlet to pass through said housing to said outlet. 
     
     
         4 . The air purification system of  claim 1 , wherein the first damper is configured to move between at least the first position and a second position. 
     
     
         5 . The air purification system of  claim 1 , further comprising a second damper configured to move between an open position and a closed position such that when said second damper is in said closed position the second damper allows air to pass from said supply duct inlet through said room air inlet. 
     
     
         6 . The air purification system of  claim 5 , further comprising an air filter, wherein said second damper is positioned such that when said second damper is in said closed position, the second damper prevents air from said supply duct inlet to contact said filter. 
     
     
         7 . The air purification system of  claim 1 , wherein said supply duct inlet obtains air from another room. 
     
     
         8 . The air purification system of  claim 4 , further comprising a fan disposed in said housing, such that when the first dampener is in the second position, said fan draws air from both said supply duct inlet and from said room air inlet through said housing to said outlet. 
     
     
         9 . The air purification system of  claim 4 , further comprising an air filter disposed in said housing, such that when the first dampener is in the second position, air from both said supply duct inlet and from said room air inlet to pass through said air filter disposed in the housing to said outlet. 
     
     
         10 . The air purification system of  claim 8 , wherein the fan is disposed between the between the first damper and the outlet. 
     
     
         11 . The air purification system of  claim 10 , further comprising an air filter disposed between the first dampener and the fan. 
     
     
         12 . The air purification system of  claim 1 , wherein the first dampener comprises a first rotatable flap. 
     
     
         13 . The air purification system of  claim 1 , wherein air purification system is configured to be removably attached to a supply duct. 
     
     
         14 . A positive pressure air purification system comprising:
 a housing having:
 a room air inlet configured to fluidly receive air from a room where the air purification system resides; 
 a supply duct configured to fluidly receive air from a source other than the room where the air purification system resides; and 
 a outlet configured to expel air into the room; and 
   said positive pressure air purification system having a first configuration which:
 (1) always allows air to pass from said supply duct inlet through said housing to said outlet; and 
 (2) selectively allows or disallows room air to pass from said room air inlet through said housing to said outlet. 
   
     
     
         15 . The air purification system of  claim 14 , wherein said positive pressure air purification system has a second configuration, distinct from the first configuration which allows air from said supply duct inlet to pass from said supply duct inlet through said housing to said outlet. 
     
     
         16 . The air purification system of  claim 14 , wherein said second configuration prevents air from said room air inlet to pass through said housing to said outlet. 
     
     
         17 . The air purification system of  claim 15 , wherein said positive pressure air purification system has a third configuration, distinct from the first and second configurations, wherein the third configuration allows air to pass from said supply duct inlet through said room air inlet.