Abstract: A system for determining remotely the distance from the bottom of a storage tank to the liquid-vapor interface of the stored liquid utilizing a pair of solid state electrical sensing elements whose electrical resistance varies as a function of element heat dissipation capable of providing continuous extremely accurate digitally displayed measurement information referenced to the bottom of the tank even when the stored liquid and vapor are at the same temperature. The solid-state electrical interface sensing elements are affixed at the end of a vertically suspended motor driven cable disposed within the storage tank which is coupled to a DC pulse activated stepping motor and a master control circuit connecting the signal output of the sensing elements to the motor. The motor and cable system in conjunction with the control circuitry provide and drive the motor in stepping increments for continuously determining the liquid-vapor interface as referenced to the bottom of the storage tank.

Abstract: A mass flow meter including a fluid volume indicating means for measuring the volume of a fluid, a temperature sensor for indicating the temperature of the fluid being measured by the fluid volume indicating means, a density compensator connected to the volume indicating means and the temperature means to provide an indication of mass flow rate of the fluid material, and counting means to accurately accumulate the indication of mass units to provide the total mass of the fluid being measured. The signal output of the volume indicating means and the temperature sensor from the temperature sensor provide input pulses to the variable pulse width means in the density compensator to initiate an output measuring envelope pulse and to cut off the output measuring envelope pulse. The envelope pulse is an input density compensated envelope pulse to the counting means. The density compensator includes an oscillator producing a high frequency output to the counter means.