Fuel dispenser flow meter having vapor pressure correction arrangement
First Claim
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1. An apparatus for measuring the flow rate of liquid fuel in a fuel dispenser, comprising:
- a positive displacement fuel flow meter configured to measure the flow rate of fuel through the meter, said positive displacement flow meter having rotating structure that creates temperature-dependent temporary vaporization of the fuel inside the flow meter;
a temperature sensor for measuring the temperature of the fuel; and
a signal processor and associated memory, said signal processor being operative to convert the measured flow rate to a corrected flow rate by applying a varying vapor compensation factor based upon and determined using temperature data from the temperature sensor.
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Abstract
A method and apparatus for improving the accuracy of fuel flow meters by compensating for the presence of vapor bubbles generated within the flow meter. The method comprises measuring the temperature of the fuel flowing through the meter and using an algorithm or static lookup table to determine a vapor compensation factor based on that temperature. Because the tendency of fuel to vaporize depends largely on seasonal variations in fuel temperature, applying a temperature-dependent vapor compensation factor promotes year-round accuracy of the flow meter output.
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Citations
18 Claims
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1. An apparatus for measuring the flow rate of liquid fuel in a fuel dispenser, comprising:
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a positive displacement fuel flow meter configured to measure the flow rate of fuel through the meter, said positive displacement flow meter having rotating structure that creates temperature-dependent temporary vaporization of the fuel inside the flow meter; a temperature sensor for measuring the temperature of the fuel; and a signal processor and associated memory, said signal processor being operative to convert the measured flow rate to a corrected flow rate by applying a varying vapor compensation factor based upon and determined using temperature data from the temperature sensor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A fuel dispenser for dispensing liquid fuel, said fuel dispenser comprising:
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a housing; internal piping located in said housing for fluid communication with a source of fuel; a flexible hose external to said housing, a proximal end of said hose being in fluid communication with said internal piping; a nozzle located at a distal end of the flexible hose; and a positive displacement fuel flow meter configured to measure the flow rate of the liquid fuel through the meter, said positive displacement flow meter having rotating structure that creates temperature-dependent temporary vaporization of the fuel inside the flow meter; a temperature sensor associated with said internal piping for measuring the temperature of the fuel; and a signal processor and associated memory, said signal processor being operative to convert the measured flow rate to a corrected flow rate by applying a vapor compensation factor based upon and determined using temperature data from the temperature sensor. - View Dependent Claims (11)
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12. A method of measuring the flow rate of liquid fuel in a fuel dispenser, comprising:
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providing a positive displacement fuel flow meter that measures the flow rate of fuel through the meter, said positive displacement flow meter having rotating structure that creates temperature-dependent temporary vaporization of the fuel inside the flow meter; measuring the temperature of the fuel using a temperature sensor; and converting the measured flow rate to a corrected flow rate by applying a varying vapor compensation factor based upon and determined using temperature data from the temperature sensor. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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Specification