Steam generator for domestic household appliance

Abstract

A household appliance includes a housing having a door formed in a front panel thereof for accessing an interior of the housing, a tub disposed inside the housing for containing a liquid, the tub having an inner surface and an outer surface, and a steam generator. The steam generator includes a heating element inside the tub, and a liquid level sensor on the outer surface of the tub, the liquid level sensor detecting a level of the liquid inside the tub, wherein the liquid level sensor includes a non-contacting sensor that detects the level of the liquid without directly contacting the liquid.

1 . A washer comprising:
 a housing having a door formed in a front panel thereof for accessing an interior of the housing;   a tub disposed inside the housing for containing a liquid, the tub having an inner surface and an outer surface;   a drum rotatably mounted in the tub for receiving laundry through the door, the drum including a circumferential wall having an inner surface and an outer surface, the outer surface of the circumferential wall being adjacent to the inner surface of the tub; and   a steam generator that generates steam from the liquid in the tub, the steam generator including:
 a heating element inside the tub and disposed between a lower portion of the outer surface of the circumferential wall of the drum and a lower portion of the inner surface of the tub; and 
 a liquid level sensor on the outer surface of the tub, the liquid level sensor detecting a level of the liquid inside the tub. 
   
     
     
         2 . The washer of  claim 1 , wherein the liquid level sensor is disposed entirely on the outer surface of the tub. 
     
     
         3 . The washer of  claim 1 , wherein the liquid level sensor includes a thin film sensor. 
     
     
         4 . The washer of  claim 1 , wherein the liquid level sensor includes a field effect sensor. 
     
     
         5 . The washer of  claim 1 , wherein the liquid level sensor includes a non-contacting sensor that detects the level of the liquid without directly contacting the liquid. 
     
     
         6 . The washer of  claim 1 , comprising:
 a controller in communication with the heating element and the liquid level sensor, the controller selectively controlling operation of the heating element for generating steam based on the level of the liquid detected by the liquid level sensor.   
     
     
         7 . The washer of  claim 6 , comprising:
 a liquid supply unit that supplies the liquid to the tub;   wherein the controller is in communication with the liquid supply unit, the heating element, and the liquid level sensor, the controller selectively controlling operation of the liquid supply unit and the heating element based on the level of the liquid detected by the liquid level sensor.   
     
     
         8 . The washer of  claim 1 , comprising:
 a liquid supply unit that supplies the liquid to the tub;   a controller in communication with the liquid supply unit and the liquid level sensor, the controller selectively controlling operation of the liquid supply unit based on the level of the liquid detected by the liquid level sensor.   
     
     
         9 . The washer of  claim 1 , wherein the liquid level sensor includes:
 a first liquid level sensor on the outer surface of the tub, wherein the first liquid level sensor detects a presence of the liquid on the inner surface of the tub that is opposed to the first liquid level sensor.   
     
     
         10 . The washer of  claim 9 , wherein the liquid level sensor includes:
 a second liquid level sensor on the outer surface of the tub, wherein the second liquid level sensor detects a presence of the liquid on the inner surface of the tub that is opposed to the second liquid level sensor.   
     
     
         11 . The washer of  claim 10 , wherein the liquid level sensor includes:
 a third liquid level sensor on the outer surface of the tub, wherein the third liquid level sensor detects a presence of the liquid on the inner surface of the tub that is opposed to the third liquid level sensor.   
     
     
         12 . The washer of  claim 9 , wherein the first liquid level sensor is disposed at a first location on the outer surface of the tub in a horizontal plane extending through an area between the heating element and the lower portion of the outer surface of the circumferential wall of the drum. 
     
     
         13 . The washer of  claim 12 , wherein the first location of the first liquid level sensor on the outer surface of the tub corresponds to a predetermined level of the liquid inside the tub for generating steam using the heating element. 
     
     
         14 . The washer of  claim 12 , wherein the first location of the first liquid level sensor on the outer surface of the tub corresponds to a predetermined maximum level of the liquid inside the tub for generating steam using the heating element. 
     
     
         15 . The washer of  claim 12 , wherein the first location of the first liquid level sensor on the outer surface of the tub corresponds to a predetermined minimum level of the liquid inside the tub for generating steam using the heating element. 
     
     
         16 . The washer of  claim 9 , wherein the first liquid level sensor is disposed at a location on the outer surface of the tub in a horizontal plane extending through an area above the lower portion of the outer surface of the circumferential wall of the drum. 
     
     
         17 . The washer of  claim 10 , wherein the first liquid level sensor is disposed at a first location on the outer surface of the tub in a horizontal plane extending through an area between the heating element and the lower portion of the outer surface of the circumferential wall of the drum,
 wherein the second liquid level sensor is disposed at a second location on the outer surface of the tub in a second horizontal plane extending through the area between the heating element and the lower portion of the outer surface of the circumferential wall of the drum, and   wherein the second horizontal plane is one of above and below the first horizontal plane.   
     
     
         18 . The washer of  claim 17 , wherein one of the first horizontal plane and the second horizontal plane corresponds to a predetermined maximum level of the liquid inside the tub for generating steam using the heating element, and
 wherein another of the first horizontal plane and the second horizontal plane corresponds to a predetermined minimum level of the liquid inside the tub for generating steam using the heating element.   
     
     
         19 . The washer of  claim 11 , wherein the first liquid level sensor is disposed at a first location on the outer surface of the tub in a horizontal plane extending through an area between the heating element and the lower portion of the outer surface of the circumferential wall of the drum,
 wherein the second liquid level sensor is disposed at a second location on the outer surface of the tub in a second horizontal plane extending through the area between the heating element and the lower portion of the outer surface of the circumferential wall of the drum,   wherein the second horizontal plane is one of above and below the first horizontal plane, and   wherein the third liquid level sensor is disposed at a third location on the outer surface of the tub in a third horizontal plane extending through an area above the lower portion of the outer surface of the circumferential wall of the drum.   
     
     
         20 . The washer of  claim 10 , wherein the second liquid level sensor is disposed at a second location on the outer surface of the tub on an opposite side of the tub from the location of the first liquid level sensor and substantially in a same horizontal plane as the first liquid level sensor. 
     
     
         21 . The washer of  claim 1 , wherein the tub includes:
 a heater pocket formed in the lower portion of the inner surface of the tub,   wherein the heating element is disposed in the heater pocket.   
     
     
         22 . The washer of  claim 10 , wherein the first liquid level sensor and the second liquid level sensor each include a surface mounted field effect sensor. 
     
     
         23 . The washer of  claim 11 , wherein the first liquid level sensor, the second liquid level sensor, and the third liquid level sensor each include a surface mounted field effect sensor. 
     
     
         24 . A household appliance comprising:
 a housing having a door formed in a front panel thereof for accessing an interior of the housing;   a tub disposed inside the housing for containing a liquid, the tub having an inner surface and an outer surface; and   a steam generator that generates steam from the liquid in the tub, the steam generator including:
 a heating element inside the tub; and 
 a liquid level sensor on the outer surface of the tub, the liquid level sensor detecting a level of the liquid inside the tub, 
 wherein the liquid level sensor includes a non-contacting sensor that detects the level of the liquid without directly contacting the liquid. 
   
     
     
         25 . The household appliance of  claim 24 , wherein the liquid level sensor includes a field effect sensor. 
     
     
         26 . The household appliance of  claim 24 , comprising:
 a controller in communication with the heating element and the liquid level sensor, the controller selectively controlling operation of the heating element for generating steam based on the level of the liquid detected by the liquid level sensor.   
     
     
         27 . The household appliance of  claim 26 , comprising:
 a liquid supply unit that supplies the liquid to the tub;   wherein the controller is in communication with the liquid supply unit, the heating element, and the liquid level sensor, the controller selectively controlling operation of the liquid supply unit and the heating element based on the level of the liquid detected by the liquid level sensor.   
     
     
         28 . The household appliance of  claim 24 , comprising:
 a liquid supply unit that supplies the liquid to the tub;   a controller in communication with the liquid supply unit and the liquid level sensor, the controller selectively controlling operation of the liquid supply unit based on the level of the liquid detected by the liquid level sensor.   
     
     
         29 . The household appliance of  claim 24 , wherein the liquid level sensor is disposed at a location on the outer surface of the tub corresponding to one of a predetermined level, a predetermined maximum level, and a predetermined minimum level of the liquid inside the tub for generating steam using the heating element. 
     
     
         30 . The household appliance of  claim 24 , wherein the liquid level sensor includes:
 a plurality of liquid level sensors on the outer surface of the tub, wherein each of the plurality of liquid level sensors respectively detects a presence of the liquid on the inner surface of the tub that is opposed to each of the plurality of liquid level sensors.   
     
     
         31 . The household appliance of  claim 30 , wherein a first liquid level sensor of the plurality of liquid level sensors is disposed at a first location on the outer surface of the tub corresponding to a predetermined maximum level of the liquid inside the tub for generating steam using the heating element, and
 wherein a second liquid level sensor of the plurality of liquid level sensors is disposed at a second location on the outer surface of the tub corresponding to a predetermined minimum level of the liquid inside the tub for generating steam using the heating element.   
     
     
         32 . A household appliance comprising:
 a housing having a door formed in a front panel thereof for accessing an interior of the housing;   a tub disposed inside the housing for containing a liquid, the tub having an inner surface and an outer surface;   a steam generator that generates steam from the liquid in the tub, the steam generator including:
 a heating element inside the tub; and 
 liquid level sensor means on the outer surface of the tub, the liquid level sensor means for detecting a level of the liquid inside the tub; and 
   a controller in communication with the heating element and the liquid level sensor means, the controller selectively controlling operation of the heating element for generating steam based on the level of the liquid detected by the liquid level sensor means.   
     
     
         33 . The household appliance of  claim 32 , comprising:
 a liquid supply unit that supplies the liquid to the tub;   wherein the controller is in communication with the liquid supply unit, the heating element, and the liquid level sensor means, the controller selectively controlling operation of the liquid supply unit and the heating element based on the level of the liquid detected by the liquid level sensor means.