Humidifier having a heating chamber with a continuously open drain and flushing outlet

Claim 1

A humidifier comprising: (a) a heating chamber having side walls, a lid and a bottom defining a closed heating chamber, the bottom extending downwardly from the side walls and defining a single, continuously open drain and flushing outlet located at a lowermost extremity of the bottom so as to allow continuous flushing of impurities from the heating chamber; (b) a water inlet in fluid communication with the heat chamber; (c) a steam outlet located near the top of the heating chamber to allow steam to pass outwardly from the heating chamber; (d) port means defined by the heating chamber; (e) electric water heating means located in the heating chamber and extending through the port means; (f) electrical power supply means connected to the water heating means to supply electrical power thereto; (g) an unobstructed open ended drain pipe having one open end in continuous open fluid communication with the drain and flushing outlet, the drain pipe extending up the outside of the heating chamber a predetermined height so that the other open end of the drain pipe defines a predetermined static water level inside the heating chamber; (h) a water inlet valve adapted to control the flow of water passing through the water inlet into the heating chamber; (i) means for detecting the water level in the heating chamber; (j) inlet valve control means operatively connected to the water level detecting means and to the water inlet valve to open and close the valve to maintain the level of water within the heating chamber approximately equal to the height of the drain pipe; and, (k) flushing control means comprising: (i) means for detecting the impurity level of the water in the heating chamber; and, (ii) means operatively connecting the inlet valve control means and said impurity level detecting means such that when the impurity level reaches a predetermined level the inlet valve control means opens the water inlet valve for a predetermined period of time to flush accumulated impurities out of the heating chamber through the drain and flushing outlet and the drain pipe.