Patent ID: 6668665
Filing Date: 2003-12-30
Classification: G01F

Abstract:
A gas level monitoring system for a tank, comprising:a gas flow rate sensor having: a flow tube with a flow inlet in fluid communication with the tank and a flow outlet; a diaphragm member movably mounted in the flow tube between the flow inlet and the flow outlet and having a central aperture for receiving the gas flow; a tapered plug fixedly mounted in the flow tube and having a free plug end projecting within the central aperture of the diaphragm member; a spring having a fixed end mounted in the flow tube and a movable end in contact with the diaphragm member for resiliently urging the diaphragm member into contact with one end of the tapered plug corresponding to a central aperture closed position, with the diaphragm member moved (1) away from the central aperture closed position and towards the free plug end in response to increasing gas flow rates, and (2) away from the free plug end and towards the central aperture closed position in response to decreasing gas flow rates; a magnet fixed to the movable diaphragm member for slidable movement within the flow tube and thereby responding to changing gas flow rates to provide changing magnetic flux; a magnetic flux sensor fixedly mounted adjacent the magnet for responding to the changing magnetic flux provided by the magnet and producing an output signal representing changes in a gas flow rate; a temperature sensor positioned to detect a temperature of the gas and generate a temperature signal; a pressure sensor in fluid communication with an interior of the flow tube for detecting a pressure of the gas and generating a pressure signal; and a communications link coupled to the temperature sensor, pressure sensor, and magnetic flux sensor for communicating the temperature signal, pressure signal, and output signal; and a report station communicatively coupled to the communications link for receiving the temperature signal, pressure signal, and output signal, calculating a gas flow rate based on the temperature signal, pressure signal, and output signal, determining a remaining gas level in the tank based on the calculated gas flow rate, and scheduling delivery of replacement gas to the tank.