Ultrasonic liquid measuring device for use in storage tanks containing liquids having a non-uniform vapor density
First Claim
1. A liquid level detector mounted in a petroleum tank cap, for use in determining a level of a petroleum liquid product within a storage tank comprising:
- means for locking the petroleum tank cap to a fill pipe extending into the storage tank;
ultrasonic transmitting means for transmitting an ultrasonic signal along a signal path directed at the petroleum liquid product stored in the tank;
ultrasonic receiving means for receiving an ultrasonic signal reflected from the liquid stored in the tank;
a reference reflector placed in the signal path, the reference reflector operating to reflect a reference signal back to the ultrasonic receiving means;
timing means for determining a variable, TR, representative of a time required for the ultrasonic signal to travel to the reference reflector and back, and a variable, TL, representative of a time for the ultrasonic signal to travel to a surface of the petroleum liquid product and back; and
a processor for computing the level of the petroleum liquid product within the storage tank using an expression, e.sup.α
·
TL.spsp.β
1 ·
TR.spsp.β
2, which includes a compensation for a non-uniform vapor density of the petroleum liquid product, wherein e is approximately equal to 2.7183 and α
, β
1, and β
2 are empirically determined constants for the petroleum liquid product.
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Accused Products
Abstract
An ultrasonic liquid level detector mounted in a fill pipe cap. The ultrasonic detector mounted in a fill pipe cap (10) is used in determining a level and/or the volume of a liquid (5) stored in an underground storage tank (20). The fill pipe cap contains an ultrasonic ranging unit (50) that measures a time, TL, required for an ultrasonic pulse to travel round trip between an ultrasonic transducer/receiver (54) and the surface of the liquid in the tank. A reference reflector (25) disposed within a fill pipe (30) is used in determining a reference time, TR, that is included in a non-linear expression, e.sup.α ·TL.sup.β.sbsp.1 ·TR.sup.β.sbsp.2, in order to compute the level of liquid in the storage tank. The terms e.sup.α, β1, and β2 comprise a correction for errors in the round-trip times TL and TR caused by a non-uniform vapor density of the liquid along the path traveled by the ultrasonic pulses.
75 Citations
1 Claim
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1. A liquid level detector mounted in a petroleum tank cap, for use in determining a level of a petroleum liquid product within a storage tank comprising:
-
means for locking the petroleum tank cap to a fill pipe extending into the storage tank; ultrasonic transmitting means for transmitting an ultrasonic signal along a signal path directed at the petroleum liquid product stored in the tank; ultrasonic receiving means for receiving an ultrasonic signal reflected from the liquid stored in the tank; a reference reflector placed in the signal path, the reference reflector operating to reflect a reference signal back to the ultrasonic receiving means; timing means for determining a variable, TR, representative of a time required for the ultrasonic signal to travel to the reference reflector and back, and a variable, TL, representative of a time for the ultrasonic signal to travel to a surface of the petroleum liquid product and back; and a processor for computing the level of the petroleum liquid product within the storage tank using an expression, e.sup.α
·
TL.spsp.β
1 ·
TR.spsp.β
2, which includes a compensation for a non-uniform vapor density of the petroleum liquid product, wherein e is approximately equal to 2.7183 and α
, β
1, and β
2 are empirically determined constants for the petroleum liquid product.
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Specification
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- Resources
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Current AssigneeCapscan Sales Incorporated
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Original AssigneeCapscan Sales Incorporate
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InventorsNumata, Jerauld T., Stapleton, Charles E.
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Primary Examiner(s)YASICH, DANIEL
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Application NumberUS07/638,393Time in Patent Office393 DaysField of Search73/290 V, 340/621US Class Current73/290.00VCPC Class CodesG01F 23/2962 Measuring transit time of r...Y10S 367/908 Material level detection, e...
