Patent ID: 6655422
Filing Date: 2003-12-02
Classification: B65B,F17C

Abstract:
In a computer controlled system for filling a cylinder with a gas, the system including (a) a source of gas, (b) a plurality of valves for controlling flow of the gas to the cylinder, (c) a transducer for measuring pressure of the gas flowing to the cylinder, and (d) a weight scale for determining weight of the cylinder when filling the cylinder with the gas,a method of filling the cylinder with a target weight of the gas comprising the steps of: (a) successively measuring the weight of the cylinder at periodic time intervals to obtain successive actual weights of the cylinder; (b) opening a first valve and filling the cylinder with the gas at a high flow rate; (c) closing the first valve after reaching a predetermined weight difference between the target weight and an actual weight; (d) after step (c), opening a second valve and filling the cylinder with the gas at a low flow rate; (e) after step (d), controlling by an adjustable valve, flow of the gas to the cylinder; (f) differencing each successive actual weight measured in step (a) from the target weight of the gas to obtain a plurality of first difference values; (g) differencing adjacently measured actual weights obtained in step (a) to obtain a plurality of second difference values; and (h) controlling, by the adjustable valve, flow of the gas to the cylinder based on each first difference value and a corresponding second difference value.