Apparatus and method for calibrating a storage tank

A method for calibrating a liquid storage tank having a sensor for sensing the level of the liquid in the tank, at least one metering device for measuring the amount of liquid being dispensed into or out of the storage tank, and a processor connected to the sensor and the at least one metering device for receiving data from said sensor and at least one metering device, the method comprising the steps of:

• (a) storing a first set of data values which represent differential amounts of liquid dispensed into or out of the storage tank as measured by the at least one metering device per unit of associated differential height change as measured by the sensor;
• (b) generating a second set of data values which represent estimates of the differential amounts of liquid dispensed into or out of the storage tank per unit of associated differential height change, said second set of data values being computed using an algorithm employing a mathematical formula which expresses the differential amounts of liquid dispensed into or out of the storage tank per unit of associated differential height change as a function of the liquid level measurements and a number of calibration parameters including the dimensions of the tank and at least one of the orientation of the tank relative to gravity field and the position of the sensor inside the tank;
• and
• (c) searching for the calibration parameters which yield the minimum error between the first and second sets of data, said error being generated by a merit function the output of which produces error values, said values being such that the smaller the value the closer the agreement between the first and second sets of data and the minimum error being defined as the smallest of these values.

An apparatus for calibrating a liquid storage tank, comprising:

• (a) a sensor for sensing the level of the liquid in the tank, said sensor providing first output signals proportional to the sensed liquid levels;
• (b) at least one metering device for measuring the amount of liquid being dispensed into or out of the storage tank, said at least one metering device providing second output signals proportional to the amount of liquid being dispensed and third output signals communicating information on the beginning and end of each dispensing period;
• and
• (c) a processor having multiple inputs for receiving said first, second and third output signals, said processor being operative:
• (i) to store a first set of data values which represent differential amounts of liquid dispensed into or out of the storage as measured by the at least one metering device, said measurements being taken at various liquid levels in the tank which are measured by the sensor;
• (ii) to generate a second set of data values which represent estimates of the differential amounts of liquid dispensed into or out of the storage tank, said processor being programmed with an algorithm which employs a mathematical formula in computing said second set of data values which expresses the volume of the liquid in the (ink as a function of the liquid level measurements and a number of calibration parameters including the dimensions of the tank and at least one of the orientation of the tank relative to gravity field and the position of the sensor inside the tank;
• and
• (iii) to calibrate the tank by searching for the calibration parameters which yield the minimum error between the first and second sets of data, said error being generated by a merit function the output of which produces error values, said values being such that the smaller the value the closer the agreement between the first and second sets of data and the minimum error being defined as the smallest of these values.

An apparatus for calibrating a liquid storage tank, comprising:

• (a) a sensor for sensing the level of the liquid in the tank, said sensor providing first output signals proportional to the sensed liquid levels;
• (b) at least one metering device for measuring the amount of liquid being dispensed into or out of the storage tank, said at least one metering device providing second output signals proportional to the amount of liquid being dispensed and third output signals communicating information on the beginning and end of each dispensing period;
• and
• (c) a processor having multiple inputs for receiving said first, second and third output signals, said processor being operative:
• (i) to generate a first set of raw data values which represent differential amounts of liquid dispensed into or out of the storage tank as measured by the at least one metering device per unit of associated differential height change as measured by the sensor;
• (ii) to generate a second set of data values from the first set of raw data values by collapsing the data points from the first set of raw data into a limited amount of segments taken along the tank height;
• (iii) to store the second set of data values;
• (iv) to generate a third set of data values which represent estimates of the differential amounts of liquid dispensed into or out of the storage tank per unit of associated differential height change, said processor being programmed with an algorithm which employs a mathematical formula for computing said third set of data values which expresses the differential amounts of liquid dispensed into or out of the storage tank per unit of associated differential height change as a function of the liquid level measurements and a number of calibration parameters;
• and
• (v) to calibrate the rank by searching for the calibration parameters which yield the minimum error between the second and third sets of data, said error being generated by a merit function the output of which produces error values, said values being such that the smaller the value the closer the agreement between the second and third sets of data and the minimum error being defined as the smallest of these values.

An apparatus for calibrating a liquid storage tank, comprising:

• (a) a sensor for sensing the level of the liquid in the tank, said sensor providing first output signals proportional to the sensed liquid levels;
• (b) at least one metering device for measuring the amount of liquid being dispensed into or out of the storage tank, said at least one metering device providing second output signals proportional to the amount of liquid being dispensed and third output signals communicating information on the beginning and end of each dispensing period;
• and
• (c) a processor having multiple inputs for receiving said first, second and third output signals, said processor being operative:
• (i) to generate a first set of raw data values which represent differential amounts of liquid dispensed into or out of the storage tank as measured by the at least one metering device during a plurality of dispensing periods, said measurements being taken at various liquid levels in the tank which are measured by the sensor;
• (ii) to generate a second set of data values from the first set of raw data values by collapsing the data points from the first set of raw data into a limited amount of segments taken along the tank height;
• (iii) to store the second set of data values;
• (iv) to generate a third set of data values which represent estimates of the differential amounts of liquid dispensed into or out of the storage tank, said processor being programmed with an algorithm which employs a mathematical formula in computing said third, set of data values which expresses the volume of the liquid in the tank as a function of the liquid level measurements and a number of calibration parameters;
• and
• (v) to calibrate the tank by searching for the calibration parameters which yield the minimum error between the second and third sets of data, said error being generated by a merit function the output of which produces error values, said values being such that the smaller the value the closer the agreement between the second and third sets of data and the minimum error being defined as the smallest of these values.