Patent ID: 9696248
Date: 2017-07-04
CPC Classifications: G01N,H02B

Claim:
1. A process for operating a gas monitoring apparatus to measure gas in a tank using sensors, controllers, and algorithms comprising the steps of: a controller acquires a gas pressure signal from a gas pressure sensor connected to the tank being monitored; said controller converts said gas pressure signal into a calibrated gas pressure value in engineering units of force per unit area; said controller acquires an atmospheric pressure signal from an atmospheric pressure sensor; said controller converts said atmospheric pressure signal into a calibrated atmospheric pressure value of atmospheric pressure in engineering units of force per unit area; said controller sums said calibrated gas pressure value and said calibrated atmospheric pressure value yielding a calibrated absolute gas pressure value; said controller acquires a gas temperature signal from a gas temperature sensor; said controller converts said gas temperature signal into a calibrated gas absolute temperature value in engineering units of absolute temperature; said controller uses a gas type received from an interface to lookup a virial coefficient model equation; said controller uses said virial coefficient model equation and said absolute gas temperature to calculate a second order virial coefficient; said controller uses said second order virial coefficient, said absolute gas pressure, said absolute gas temperature, a gas constant, and a virial equation to calculate a first gas density value; said controller repeats said above steps at a selected first measurement frequency developing a first time sequence of samples comprising said calibrated absolute gas pressure value, said calibrated absolute gas temperature value, and said first gas density value at each time separated by a first measurement time interval defined by the selected first measurement frequency.