Dual polarity fan assist vent for dishwasher

Abstract

A vent for a dishwasher and a corresponding method of operation includes a plenum directing air flow from a dishwasher tub to an exterior of the dishwasher tub. A dual polarity fan is positioned within the plenum and a flapper valve is positioned within an opening in the plenum. The flapper valve configured to close when the fan pushes air and open when the fan pulls air which operations correspond to a washing cycle and a drying cycle of the dishwasher.

What is claimed is: 
     
         1 . A vent for a dishwasher comprising:
 a plenum directing air flow from a dishwasher tub to an exterior of the dishwasher tub;   a dual polarity fan positioned within the plenum; and   a flapper valve positioned within an opening in the plenum, the flapper valve configured to close when the fan pushes air and open when the fan pulls air.   
     
     
         2 . The vent of  claim 1  wherein the flapper valve is pushed against the opening when the fan pushes air during a washing cycle. 
     
     
         3 . The vent of  claim 1  wherein the flapper valve is open when the fan pulls air during a drying cycle. 
     
     
         4 . The vent of  claim 1  wherein the flapper valve is biased into the open position when the fan is off. 
     
     
         5 . The vent of  claim 4  wherein the flapper valve is biased into the open position by gravity. 
     
     
         6 . The vent of  claim 1  wherein the flapper valve includes two generally perpendicular arms that engage with an area around the opening thereby pivoting the flapper valve relative to the opening. 
     
     
         7 . The vent of  claim 1  wherein the flapper valve is configured to open less than 90 degrees relative to the opening. 
     
     
         8 . The vent of  claim 7  wherein the flapper valve is configured to open less than 45 degrees relative to the opening. 
     
     
         9 . The vent of  claim 1  wherein an edge of the flapper valve is configured to abut an inner wall of the plenum to prevent the flapper valve from fully opening relative to the opening. 
     
     
         10 . A method for venting a dishwasher comprising:
 directing air flow through a plenum from a dishwasher tub to an exterior of the dishwasher tub;   positioning a dual polarity fan within the plenum;   opening a flapper valve positioned within an opening in the plenum when the fan pushes air during a washing cycle; and   closing the flapper valve when the fan pulls air during a drying cycle.   
     
     
         11 . The method of  claim 9  further comprising pivoting the flapper valve less than 45 degrees when fully opened. 
     
     
         12 . The method of  claim 9  further comprising biasing the flapper valve into an open position when the fan is off. 
     
     
         13 . The method of  claim 11  wherein the flapper valve is biased into the open position by gravity.