Methods for measuring flow rates to detect leaks
First Claim
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1. A method for measuring the difference in volumetric flow rates between different pressures, the flow rates being produced by a leak, after compensation has been made for thermally induced changes in the volume of the liquid product in a pressurized pipeline system, comprising:
- (a) pressurizing said pipeline system to a first pressure level, and measuring those changes in the volume of product in said pipeline system that are required to maintain approximately constant pressure over a first measurement period;
(b) pressurizing said pipeline system to a second pressure level and measuring those changes in the volume of product in said pipeline system that are required to maintain approximately constant pressure over a second measurement period approximately equal in duration to the first measurement period;
(c) pressurizing said pipeline system to a third pressure level where at least two of the first, second, and third pressure levels are different, and after a period approximately equal in duration to the time between the first and second measurement periods, measuring those changes in the volume of product in said pipeline system that are required to maintain approximately constant pressure over a third measurement period approximately equal in duration to the first measurement period; and
(d) computing the temperature-compensated volume rate between the pressure of the second measurement period and the average pressure during the first and third measurement periods by subtracting the rate of change of volume during the second measurement period from the average rate of change of volume during the first and third measurement periods.
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Abstract
A method for measuring thermally corrected leak rates in a pressurized pipeline system. The pipeline system is pressurized to at least two different pressures, and changes of volume of product required to maintain approximately constant pressure are measurized at each pressure. A temperature-compensated volume rate is computed.
95 Citations
21 Claims
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1. A method for measuring the difference in volumetric flow rates between different pressures, the flow rates being produced by a leak, after compensation has been made for thermally induced changes in the volume of the liquid product in a pressurized pipeline system, comprising:
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(a) pressurizing said pipeline system to a first pressure level, and measuring those changes in the volume of product in said pipeline system that are required to maintain approximately constant pressure over a first measurement period; (b) pressurizing said pipeline system to a second pressure level and measuring those changes in the volume of product in said pipeline system that are required to maintain approximately constant pressure over a second measurement period approximately equal in duration to the first measurement period; (c) pressurizing said pipeline system to a third pressure level where at least two of the first, second, and third pressure levels are different, and after a period approximately equal in duration to the time between the first and second measurement periods, measuring those changes in the volume of product in said pipeline system that are required to maintain approximately constant pressure over a third measurement period approximately equal in duration to the first measurement period; and (d) computing the temperature-compensated volume rate between the pressure of the second measurement period and the average pressure during the first and third measurement periods by subtracting the rate of change of volume during the second measurement period from the average rate of change of volume during the first and third measurement periods. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method for estimating the error in a temperature-compensated volume rate computed by measuring the difference in volumetric flow rates of a liquid product in a pressurized pipeline system, comprising:
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(a) pressurizing said pipeline system to a pressure level, and measuring those changes in the volume of product in said pipeline system that are required to maintain approximately constant pressure over a first measurement period; (b) maintaining said pipeline system at said pressure level and measuring those changes in the volume of product in said pipeline system that are required to maintain approximately constant pressure over a second measurement period approximately equal in duration to the first measurement period; and (c) estimating the error in the temperature-compensated volume rate by subtracting the rate of change of volume during the second measurement period from the rate of change of volume during the first measurement period.
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20. A method for estimating the error in a temperature-compensated volume rate computed by measuring the difference in volumetric flow rates of a liquid product in a pressurized pipeline system, comprising:
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(a) pressurizing said pipeline system to a pressure level, and measuring those changes in the volume of product in said pipeline system that are required to maintain approximately constant pressure over a first measurement period; (b) maintaining said pipeline system at said pressure level and measuring those changes in the volume of product in said pipeline system that are required to maintain approximately constant pressure over a second measurement period approximately equal in duration to the first measurement period; (c) maintaining said pipeline system at said pressure level and after a period approximately equal in duration to the time between the first and second measurement periods, measuring those changes in the volume of product in said pipeline system that are required to maintain approximately constant pressure over a third measurement period approximately equal in duration to the first measurement period; and (d) estimating the error in the temperature-compensated volume rate by subtracting the rate of change of volume during the second measurement period from the average rate of change of volume during the first and third measurement periods. - View Dependent Claims (21)
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Specification