Dishwasher appliance with temperature actuated ventilation

Abstract

A ventilation system for a dishwashing appliance is provided. An actuator that is activated by heat provided by operation of the dishwasher is used to move a gate so as to provide an open position where one or more openings are created though which heat and fluid may be vented from the wash chamber. Upon cooling the actuator, it allows the gate to move to a closed position blocking the flow of heat and fluid from the wash chamber. The application of heat or cooling changes the shape of the actuator so as to provide for the positioning of the gate.

1 . A dishwasher appliance, comprising:
 a chamber for the receipt of articles for cleaning;   a door for selectively opening and closing the dishwasher appliance, said door having an interior wall defining a first aperture for the egress of fluid from said chamber;   a vent for controlling the egress of fluid from said chamber, said vent received into said door, said vent comprising
 a movable gate defining a second aperture for the egress of fluid from said chamber, said movable gate positioned adjacent to the first aperture of the interior wall of said door, said movable gate having a closed position wherein said movable gate blocks the flow of fluid from said chamber and an open position where the second aperture of said movable gate is aligned with the first aperture of said door such that fluid can flow from said chamber; and, 
 an actuator positioned in contact with said movable gate, said actuator configured for moving said movable gate into the open position with heating of said actuator, said actuator configured for allowing said movable gate to move into the closed position with cooling of said actuator. 
   
     
     
         2 . A dishwasher appliance as in  claim 1 , wherein said actuator comprises a shape-memory alloy. 
     
     
         3 . A dishwasher appliance as in  claim 1 , wherein said actuator comprises a two-way, shape memory alloy. 
     
     
         4 . A dishwasher appliance as in  claim 1 , wherein said door defines a pair of opposing guides into which opposing sides of said movable gate are received such that said movable gate may slide along said opposing guides between the closed position and the open position. 
     
     
         5 . A dishwasher appliance as in  claim 1 , wherein said movable gate has a top edge and a bottom edge, and wherein said actuator is in contact with the bottom edge of said movable gate. 
     
     
         6 . A dishwasher appliance as in  claim 5 , further comprising a spring in contact with the top edge of said movable gate, said spring having a compressed state when said movable gate is in the open position. 
     
     
         7 . A dishwasher appliance as in  claim 1 ,
 wherein said door defines a pair of opposing guides into which opposing sides of said movable gate are received such that said movable gate may slide along said opposing guides between the closed position and the open position;   wherein said movable gate has a top edge and a bottom edge, and wherein said actuator is in contact with the bottom edge of said movable gate; and,   further comprising a spring in contact with the top edge of said movable gate, said spring having a compressed state when said movable gate is in the open position.   
     
     
         8 . A dishwasher appliance as in  claim 1 , wherein the first aperture is located near a top portion of said door. 
     
     
         9 . A dishwasher appliance, comprising:
 a chamber for the receipt of articles for cleaning;   a door for selectively accessing said chamber; said door defining a first plurality of apertures for the venting of fluid from said chamber;   a gate connected with said door, said gate defining a second plurality of apertures for the venting of fluid from said chamber, said gate movable between a closed position and an open position, wherein the flow of fluid from said chamber through said gate is blocked in the closed position and allowed in the open position by the alignment of said first and second plurality of apertures; and,   an actuator in mechanical communication with said gate, said actuator configured for positioning said gate between the closed position and the open position in response to heating and cooling of the actuator.   
     
     
         10 . A dishwasher appliance as in  claim 9 , wherein said actuator comprises a shape-memory alloy. 
     
     
         11 . A dishwasher appliance as in  claim 9 , wherein said actuator comprises a two-way, shape memory alloy. 
     
     
         12 . A dishwasher appliance as in  claim 9 , wherein said door defines a pair of opposing guides into which opposing sides of said movable gate are received such that said movable gate may slide along said opposing guides between the closed position and the open position. 
     
     
         13 . A dishwasher appliance as in  claim 12 , further comprising a spring configured for pressing upon a top edge of said door to return said door to the closed position. 
     
     
         14 . A dishwasher appliance as in  claim 12 , further comprising a pair of springs configured for pressing upon a top edge of said door to return said door to the closed position. 
     
     
         15 . A method for venting a chamber of a dishwasher, the dishwasher having a gate for controlling the flow of fluid out of the chamber, the method comprising the steps of:
 heating an actuator that is connected with the gate;   moving the gate using changes in the shape of the actuator so as place the gate into a position that allows for the flow of fluid out of the chamber;   cooling the actuator that is connected with the gate; and,   changing the shape of the actuator while moving the gate to another position that blocks the flow of fluid out of the chamber.   
     
     
         16 . A method for venting a chamber of a dishwasher as in  claim 15 , wherein said heating step comprises contacting said actuator with heated fluid from the chamber. 
     
     
         17 . A method for venting a chamber of a dishwasher as in  claim 15 , wherein said heating step comprises transferring from fluid in the chamber to the actuator. 
     
     
         18 . A method for venting a chamber of a dishwasher as in  claim 15 , wherein said actuator is a shape memory alloy. 
     
     
         19 . A method for venting a chamber of a dishwasher as in  claim 15 , wherein said step of changing further comprises pressing upon the gate using a compressed spring. 
     
     
         20 . A vent mechanism for venting an enclosed space, the mechanism comprising:
 a wall portion defining a first aperture for the release of fluid from the enclosed space;   a movable gate attached to said wall portion proximate the first aperture, said movable gate defining a second aperture for the release of fluid from said enclosed space, said movable gate having a closed position wherein said movable gate blocks the flow of fluid from the enclosed space and an open position where the second aperture of said movable gate is aligned with the first aperture of said wall portion such that fluid can flow from the enclosed space; and,   an actuator positioned in contact with said movable gate, said actuator configured for moving said movable gate into the open position upon being heated by a fluid from the enclosed space, said actuator configured for allowing said movable gate to move into the closed position with cooling of said actuator.