Elliptical beam load cell

Abstract

A humidifier for use with a hot air furnace has an upper and lower housing removably connected to one another. The upper housing has a heating element and sensor, water refill inlet, and a control circuit connected to the heat sensor and inlet. The lower housing contains a water vessel and a water level sensor secured the lower housing to receive the water vessel. The water sensor registers the minimum and maximum water weight and is connected to the control circuit. A bacteria resistant, semi-flexible removable liner fits within the vessel for the removal of built up mineral residue. Preferably the water sensor is an elliptical beam load cell with an open center surrounded by a rim and a pair of tab ends opposite one another. At least one bridge is machined within the rim to increase sensitivity. A strain gage registers strain changes and an electronic connector transfers the changes to the control circuit where they are converted to the current weight. Multiple steps along the rim receive the water vessel in insulating gaskets to prevent horizontal movement and temperature transfer. Ball bearings within the tabs balance the cell on a support ledge to allow for surface variations. Spring/screw combinations maintain the ball bearings in contact with the support ledge during mounting.