Liquid level measuring apparatus

In a liquid level measuring apparatus having 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 axis of the apparatus and a float carrying magnetic means movably positioned adjacent said plurality of switches, said magnetic means having a magnetic field for sequentially actuating switches as the float moves relative to the switches, the improvement comprising,

• a microprocessor electrically connected to the liquid level measuring apparatus,
• said switches electrically connected together in parallel in a plurality of sets,
• a plurality of shift registers, each register connected to one of the sets of switches, said registers connected together and to the microprocessor for supplying a parallel to serial conversion of the open or closed status of each switch,
• said microprocessor providing an output signal indicating the vertical position of the float relative to said switches, and
• said magnetic field is effective for providing a sequential activation of at least two and then at least the next three switches of said plurality of switches at all times.

In a liquid level measuring apparatus having a plurality of spaced reed switches vertically aligned for positioning in a liquid, each reed switch vertically overlapping the adjacent above and below reed switch, the longitudinal axis of said reed switches being at an angle to the vertical axis of the apparatus and a float means carrying magnetic means movably positioned adjacent said plurality of switches, said magnetic means having a magnetic field for sequentially actuating switches as the float means moves relative to the switches, the improvement comprising,

• a microprocessor electrically connected to the liquid level measuring apparatus,
• said switches electrically connected together in parallel in a plurality of sets,
• a plurality of shift registers, each register connected to one of the sets of switches, said registers connected together and to the microprocessor for supplying a parallel to serial conversion of the open or closed status of each switch,
• said microprocessor providing an output signal indicating the vertical position of the float means relative to said switches, and
• said float means including first and second separate floats having different buoyancies for simultaneous measuring the level of two liquids of different densities.

In a liquid level measuring apparatus having 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 axis of the apparatus and a float carrying magnetic means movably positioned adjacent said plurality of switches, said magnetic means having a magnetic field for sequentially actuating switches as the float moves relative to the switches, the improvement comprising,

• a microprocessor electrically connected to the liquid level measuring apparatus,
• said switches electrically connected together in parallel in a plurality of sets,
• a plurality of shift registers, each register connected to one of the sets of switches, said registers connected together and to the microprocessor for supplying a parallel to serial conversion of the open or closed status of each switch,
• said microprocessor providing an output signal indicating the vertical position of the float relative to said switches, and
• means connected to the microprocessor for noting inoperative switches and disregarding the reading of the inoperative switches.