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.

Description

FIELD OF THE INVENTION[0001]The present invention is directed toward a domestic household appliance, and more specifically, toward a steam generator for a domestic household appliance.BACKGROUND OF THE INVENTION[0002]A household appliance, such as a front-loading clothes washer, includes a housing having a door providing access to a washing unit in the interior of the appliance housing. The washing unit includes a watertight tub for holding washing / rinsing liquid. A cylindrical washing drum is rotatably mounted inside the tub. In operation, clothes or laundry are inserted into the washer through the door and placed in the rotating washing drum inside the tub. In a washing cycle, the household appliance wets the laundry to be washed with washing liquid and mechanically moves the laundry to release contaminants from the laundry. In a rinsing cycle, the household appliance wets the laundry to be rinsed with rinsing liquid and mechanically moves the laundry to release the residual washi...

AI Technical Summary

Benefits of technology

[0011]The present invention recognizes that it is desirable to provide a steam generating function while also minimizing additional parts and manufacturing costs. The present invention recognizes that important benefits, such as reducing costs, can be provided over the conventional devices by using the existing or “standard” heating element within the tub of the washer as the heat source for generating steam in the tub. The present invention also recognizes that there are difficult challenges associated with using the existing or “standard” heating element to generate steam in the tub.

[0012]For example, in a normal washing / rinsing cycle, the level of the washing / rinsing liquid in the tub may be permitted to rise high enough so that the washing / rinsing liquid intrudes into the rotating drum for wetting the laundry. In contrast, the laundry is not submerged in water during a steam mode or steam generating cycle using the heating element. In this case, the present invention recognizes that a level of the water supplied to the heater pocket for generating steam must be controlled such that the water level is low enough in the tub to prevent the water from contacting or intruding into the rotating drum, yet high enough to immerse the heating element in a sufficient mass of water for generating steam without exposing the heating element. The present invention recognizes that a distance between the heating element and the rotating drum in many conventional devices is small, and hence, the range of acceptable water levels is limited for achieving the desired steam generating function while preventing wetting of the laundry in the drum.

Problems solved by technology

Conventionally, water level sensors have not been adequate to closely and accurately control the water level in such a limited and sensitive range.

The present invention recognizes that such analog pressure sensors generally are not highly reliable devices for providing accurate and repeatable water levels, and hence, the conventional pressure sensors cannot maintain a reliable and accurate water level during a steam generation cycle.

Also, these conventional sensors commonly require the tub to be modified to include a penetration of the wall of the tub for attaching or inserting the sensor and / or transferring the signal from the sensor to a control unit outside the tub, which may affect the watertight characteristics of the tub and may increase the likelihood of water leaking from the tub.

Furthermore, the conventional devices commonly require numerous parts and connections, for example, between the inside of the tub and the outside of the tub, thereby resulting in an increase in the number of parts, which in turn increases the material and assembly costs of the washer.

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