Method and apparatus for detecting a blockage in a vapor flow line
First Claim
1. A method for detecting blockage in a vapor flow line adapted to communicate vapor from a container adapted to hold a variable amount of fluid to a point remote from the container, said method comprising the steps of:
- obtaining a first signal representative of the pressure in the vapor flow line;
producing a second signal representative of the rate of change with time of said first signal; and
detecting if the frequency of the variations in said second signal exceeds a first preset limit to detect a blockage in the vapor flow line.
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Accused Products
Abstract
A method and apparatus for detecting blockages in one or more vapor flow lines such as vapor recovery lines used in liquid gasoline dispensing systems. The method and apparatus operate by sensing pressure in vapor flow lines and determining whether the frequency of the variations in the filtered rate of change with time of the pressure signal exceeds a preset limit indicating vapor bubbling through a liquid blockage. The method and apparatus also operate to determine whether the pressure signal exceeds a preset limit indicating a blockage condition.
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Citations
24 Claims
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1. A method for detecting blockage in a vapor flow line adapted to communicate vapor from a container adapted to hold a variable amount of fluid to a point remote from the container, said method comprising the steps of:
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obtaining a first signal representative of the pressure in the vapor flow line; producing a second signal representative of the rate of change with time of said first signal; and detecting if the frequency of the variations in said second signal exceeds a first preset limit to detect a blockage in the vapor flow line. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for detecting a blockage in a vapor return line in a liquid dispensing and vapor recovery system comprising a storage tank for storing liquid to be dispensed, means adapted for dispensing liquid from said storage tank into a container, a fluid line for communicating liquid from said storage tank to said dispensing means, and a vapor return line adapted for communicating vapor from a container being filled with liquid dispensed from said dispensing means to said storage tank, said method comprising the steps of:
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obtaining a first signal representative of the pressure in the vapor return line; producing a second signal representative of the rate of change with time of said first signal; and detecting if the frequency of the variations in said second signal exceeds a first preset limit to detect a blockage in the vapor return line. - View Dependent Claims (9, 10)
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11. Apparatus for detecting blockage in a vapor flow line adapted to communicate vapor from a container adapted to hold a variable amount of fluid to a point remote from the container, said apparatus comprising:
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means for producing a first signal representative of the pressure in the vapor flow line; means for producing a second signal representative of the rate of change with time of said first signal; and means for detecting if the frequency of the variations in said second signal exceeds a first preset limit to detect a blockage in the vapor flow line. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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19. Apparatus for detecting a blockage in a vapor return line in a liquid dispensing and vapor recovery system comprising:
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a storage tank for storing liquid to be dispensed; means adapted for dispensing liquid from said storage tank into a container; a vapor return line adapted for communicating vapor from a container being filled with liquid dispensed from said dispensing means to said storage tank; means for producing a first signal representative of the pressure in the vapor return line; means for producing a second signal representative of the rate of change with time of said first signal; and means for detecting if the frequency of the variations in said second signal exceeds a first preset limit to detect a blockage in the vapor return line. - View Dependent Claims (20, 21, 22, 23, 24)
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Specification