High pressure liquid level monitor

A system for tracking increases in liquid level in a vessel and generating a control signal therefrom comprising:

• float means in said vessel movable along a vertical path with changes in said liquid level, said float means including magnetically permeable material;
• first magnetic field generating means disposed outside said vessel adjacent the bottom thereof for applying an alternating electromagnetic field to said magnetically permeable material in said float means;
• second magnetic field generating means disposed outside said vessel adjacent the top thereof for applying an alternating electromagnetic field to said magnetically permeable material in said float means;
• first magnetic field detector means magnetically coupled to said first magnetic field generating means through the magnetically permeable material in said float means for sensing the strength of the magnetic field in the magnetically permeable material of said float means attributable to said first magnetic field generating means and generating a first float height signal as a function of increases in said liquid level;
• second magnetic field detector means magnetically coupled to said second magnetic field generating means through the magnetically permeable material in said float means for sensing the strength of the magnetic field in the magnetically permeable material of said float means attributable to said second magnetic field generating means and generating a second float height signal as a function of increases in said liquid level;
• first rectifier means connected to said first magnetic field detector means for converting said first float height signal from A.C. to D.C.;
• second rectifier means connected to said second magnetic field detector means for converting said second float height signal from A.C. to D.C.;
• divider means connected to said first and second rectifier means for dividing said second float height D.C. Signal by said first float height D.C. signal to generate a D.C. control signal which is a monitonically increasing function of float height;
• and
• oscillator means for generating an alternating current signal of a predetermined frequency and amplitude for driving said first and second magnetic field generator means, said first magnetic field generator means including a first primary coil means disposed outside said vessel adjacent the bottom thereof and connected to said oscillator means for receiving said alternating current signal, generating an alternating electromagnetic field in response thereto and applying said field to said magnetically permeable material in said float means, said second magnetic field generator means including second primary coil means disposed outside said vessel adjacent the top thereof and connected to said oscillator means for receiving said alternating current signal, generating an alternating magnetic field in response thereto and applying said magnetic field to said magnetically permeable material in said float means, said first magnetic field detector means including first secondary coil means disposed adjacent said first primary coil means and magnetically coupled thereto through the magnetically permeable material in said float means, said first secondary coil means sensing the strength of said magnetic field attributable to said first primary coil means and generating a first float height signal as a function of increases in said liquid level, said second magnetic field detector means including second secondary coil means disposed adjacent said second primary coil means and magnetically coupled thereto through the magnetically permeable material in said float means, said second secondary coil means sensing the strength of said magnetic field attributable to said second primary coil means and generating a second float height signal as a function of increases in said liquid level.