Verification of scale calibration method and apparatus

An article comprising a computer-readable medium which stores computer-executable instructions, the instructions causing a computer to:

• weigh a storage tank of a fluid at a first time with a scale;
• transfer the fluid from the storage tank to an area of known volume;
• weigh the storage tank at a second time with the scale, after fluid has been moved to the area of known volume;
• determine a pressure of the fluid in the area of known volume with a pressure sensor;
• calculate a temperature of the fluid in the area of known volume with the determined pressure;
• calculate the weight of fluid in the area of known volume based on the calculated temperature;
• compare a difference in weight of the storage tank between the first and second weighing times with the weight of the fluid in the area of known volume;
• and
• send a first signal to a user indicating a calibration of the scale is not needed if the difference between the compared weights of the fluid is within a predetermined range.

A fluid handling device configured to perform the steps of checking a calibration of a scale comprising:

• step for weighing a storage tank of a fluid at a first time with the scale;
• step for transferring the fluid from the storage tank to an area of known volume;
• step for weighing the storage tank at a second time with the scale, after fluid has been moved to the area of known volume;
• step for determining a pressure of the fluid in the area of known volume with a pressure sensor;
• step for calculating a temperature of the fluid in the area of known volume with the determined pressure;
• step for calculating the weight of fluid in the area of known volume based on the calculated temperature;
• step for comparing a difference in weight of the storage tank between the first and second weighing with the weight of the fluid in the area of known volume;
• step for sending a first signal to a user indicating a calibration is not needed if the difference between the compared weights of the fluid is within a predetermined range;
• and
• step for sending a second signal to a user indicating the calibration is needed if the difference between the compared weights of the fluid is not within a predetermined range.

A method of determining whether a scale in a fluid handling device needs to be calibrated, comprising:

• weighing a storage tank of a fluid at a first time with a scale;
• transferring the fluid from the storage tank to an area of known volume;
• weighing the storage tank at a second time with the scale, after fluid has been moved to the area of known volume;
• determining the temperature of the fluid in the area of known volume with a temperature sensor;
• calculating the weight of fluid in the area of known volume based on the determined temperature;
• comparing a difference in weight of the storage tank between the first and second weighing times with the weight of the fluid in the area of known volume;
• and
• sending a first signal to a user indicating a calibration of the scale is not needed if the difference between the compared weights of the fluid is within a predetermined range.