Apparatus and process for measuring changes in effect of tidal forces
First Claim
1. In combination:
- a measuring device used in conjunction with leak detector system means which measures leakage of liquid into or out of liquid storage tanks, for providing a correction in said leak detector system means to account for liquid level changes caused by tidal forces, the combination comprising;
leak detector system means for monitoring the liquid level in a liquid storage tank;
a first container for a measuring liquid, and a second container for the measuring liquid, the first and second containers being positioned at a predetermined distance from one another, each of the first and second containers being isolated from fluid-communication with the liquid storage tank;
a duct in fluid communication with the first container and with the second container, thereby placing the first and second containers in fluid communication with one another;
first means for monitoring the level of the measuring liquid in the first container, the first means providing a first output signal indicative of the level of the measuring liquid in the first container; and
second means for monitoring the level of the measuring liquid in the second container, the second means providing a second output signal indicative of the level of the measuring liquid in the second container, the difference between the first and second output signals being indicative of the difference in the heights of the measuring liquid columns in the first and second containers, and is thereby indicative of the tidal forces effects on the measuring liquid in the containers.
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Accused Products
Abstract
Changes in the tide effects at a given location are measured by monitoring the respective levels of a measuring liquid in two containers which are in fluid communication with one another. The liquid levels are measured by suitable transducers including floats, and result in electronic signals indicative of the respective positions of the floats. A difference between the two signals is either computed or obtained from a differential amplifier into which the signals indicative of the respective float positions are inputted. A change in the difference between the float positions measures a change in the tidal effects at the location. The change in tidal effects is advantageously measured in conjunction with measuring leakage of liquid from liquid storage tanks, such as fuel storage tanks of filling stations, where tide effects occur and must be taken into account. The measured change in tide effects is inputted into a computer which also receives the input of a float containing transducer system measuring liquid level in the storage tank. The measured tide effects are then taken into consideration when the leakage rate of the tank is computed.
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Citations
28 Claims
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1. In combination:
- a measuring device used in conjunction with leak detector system means which measures leakage of liquid into or out of liquid storage tanks, for providing a correction in said leak detector system means to account for liquid level changes caused by tidal forces, the combination comprising;
leak detector system means for monitoring the liquid level in a liquid storage tank; a first container for a measuring liquid, and a second container for the measuring liquid, the first and second containers being positioned at a predetermined distance from one another, each of the first and second containers being isolated from fluid-communication with the liquid storage tank; a duct in fluid communication with the first container and with the second container, thereby placing the first and second containers in fluid communication with one another; first means for monitoring the level of the measuring liquid in the first container, the first means providing a first output signal indicative of the level of the measuring liquid in the first container; and second means for monitoring the level of the measuring liquid in the second container, the second means providing a second output signal indicative of the level of the measuring liquid in the second container, the difference between the first and second output signals being indicative of the difference in the heights of the measuring liquid columns in the first and second containers, and is thereby indicative of the tidal forces effects on the measuring liquid in the containers. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
- a measuring device used in conjunction with leak detector system means which measures leakage of liquid into or out of liquid storage tanks, for providing a correction in said leak detector system means to account for liquid level changes caused by tidal forces, the combination comprising;
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13. A measuring device to measure the effect of tidal forces at any selected location on substantially solid ground on the surface of the earth, the device comprising:
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a first container for a measuring liquid and a second container for a measuring liquid, the first and second containers being spaced from one another disposed along an axis; duct means for establishing fluid communication between the first and second containers, the first and second containers being disposed relative to one another on sufficiently level support surface so that the measuring liquid is present in both containers, the first and second containers being isolated from fluid communication with substantial volumes of liquid so that neither the first container nor the second container is in fluid communication with a liquid storage tank or with a liquid holding balancing tank; first and second float means disposed respectively in the first and second containers, the first and second float means each being adapted for indicating the level of the measuring liquid in the respective container; first and second sensing and signal generating means, each sensing and signal generating means being adapted for generating, respectively, first and second signals indicative, respectively, of the positions of the respective float means; first and second amplifier means, the first amplifier means being adapted for receiving as input the first signal and for generating an amplified first output signal indicative of the position of the first float means, and the second amplifier means being adapted for receiving as input the second signal indicative of the position of the second float means, the difference between the first and second output signals being substantially linearly proportional to the difference of the heights of the levels of the measuring liquid, respectively, in the first and second containers. - View Dependent Claims (14, 15, 16)
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17. A leak detector system for detecting leakage of liquid into or out of storage tanks, the leak detector system comprising:
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first means for monitoring the level of the liquid in the storage tank, the first means being adapted for generating a first signal indicative of the level of the liquid in the storage tank, the tank having a substantially horizontally disposed longitudinal axis; a first container for a measuring liquid, and a second container for the measuring liquid, the first and second containers being in fluid communication with one another through a duct and being disposed at a measured distance from one another in proximity of the storage tank and along an axis which is substantially parallel with the longitudinal axis of the storage tank, neither the first container nor the second container being in fluid communication with the storage tank, and second means for monitoring the difference between the levels of the measuring liquid in the first and second containers, the second means adapted for generating a second signal which is indicative of said difference and is thereby indicative of tidal effects on the measuring liquid contained in the containers, the second signal providing a value serving as a correction to a value derived from the first signal, whereby the rate of leakage calculated from the first and second signals substantially eliminates an error due to occurrence of tidal effects in the storage tank. - View Dependent Claims (18, 19, 20, 21)
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22. A process for determining changes in the magnitude of tidal effects at a given location, the process comprising the steps of:
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maintaining a measuring liquid in two spaced apart containers which are in fluid communication with one another and which are isolated from any extraneous volume of liquid such as a storage tank or liquid holding balancing tank; measuring the level of the measuring liquid in each of the containers, the step of measuring comprising a step of obtaining a signal with respect to each container which is indicative of the instantaneously measured level of the measuring liquid in each container; and obtaining a difference signal which is indicative of the difference between the instantaneously measured signals in each container, changes in said difference signal during a time period being indicative of the changes in the tidal effects at the given location during the time period. - View Dependent Claims (23, 24)
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25. A process for measuring leakage of a liquid storage tank, the process comprising:
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maintaining a float in the storage tank to track the level of the stored liquid; measuring the position of the float in the stored liquid and obtaining a first signal which is indicative of the instantaneous position of the float in the stored liquid; maintaining a first container and a second container in fluid communication with one another and in the proximity of the liquid storage tank, the axis interconnecting the first and second containers being disposed substantially parallel with the horizontal longitudinal axis of the storage tank, and maintaining a measuring liquid in the first and second containers; measuring the difference between the heights of the columns of measuring liquid in the first and second containers, and obtaining a second signal which is indicative of said difference; performing the above-defined steps of measuring at least at the beginning and at the end of a predetermined time period, the difference between the first signals obtained at the beginning and at the end, respectively, being indicative of apparent leakage of the storage tank during the time period, and the difference between the second signals obtained at the beginning and at the end respectively being indicative of a change in tidal effects during the time period, the difference between the second signals providing a corrective factor for calculating actual leakage of the storage tank during the time period. - View Dependent Claims (26, 27, 28)
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Specification