Liquid level measuring apparatus

Claim 1

A liquid level measuring apparatus comprising: a plurality of spaced reed switches vertically aligned for positioning in a liquid, each reed switch vertically overlapping the adjacent above and below reed switches, the longitudinal axis of said reed switches being at an angle to the vertical, a float carrying magnetic means movably positioned coaxially about said plurality of switches, the magnetic polarity of said magnetic means being vertically aligned, the magnetic means having a magnetic field in which the vertical strength is effective for sequentially and alternately actuating only one and then two switches as the float movers relative to the switches without actuating any other switches, said magnetic field is oriented relative to the reed switches and at a distance from the switches to provide a single defined actuation of each switch as the magnetic means moves relative to the switches, a digital driver circuit connected to each reed switch, and electrical indicating means, connected to said digital driver circuits, for indicating a vertical position of the float relative to said switches, wherein said reed switches, said magnetic means and said indicating means are configured so that said indicating means has a resolution corresponding to a half of the distance between said spaced reed switches.