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US 10,852,235 B2Granted
Ultralow range fluorometer calibration
AssigneeEcolab USA Inc.
InventorSeong-Hoon Yoon
Life of this patent
Estimating the term…
Abstract
A fluorometer may be used to measure ultralow concentrations of fluorescing species, such as ultralow concentrations of fluorescent tracer passing through a reverse osmosis membrane into a permeate stream. In some examples, the fluorometer may be recalibrated by resetting some but not all of the calibration parameters used to determine the concentration of fluorescent tracer in the permeate based on the measured fluorescent response of the fluorometer. For example, an intercept of a calibration curve may be reset or recalibrated for the fluorometer in situ, potentially providing significant accuracy improvements even though the fluorometer has not undergone a full recalibration.
Claims27
A method of calibrating a fluorometer used to monitor a reverse osmosis membrane separation process comprising:
- introducing a fluorescent tracer into a feed stream to provide a first concentration of fluorescent tracer in the feed stream;
- contacting a membrane with the feed stream, thereby generating a permeate stream and a concentrate stream;
- fluorometrically analyzing the permeate stream generated from the feed stream having the first concentration of fluorescent tracer with a fluorometer and determining therefrom a first measured concentration of the fluorescent tracer in the permeate stream based on a stored calibration curve that includes an intercept;
- adjusting a concentration of the fluorescent tracer in the feed stream to provide a second concentration of fluorescent tracer in the feed stream different than the first concentration;
- fluorometrically analyzing the permeate stream generated from the feed stream having the second concentration of fluorescent tracer with the fluorometer and determining therefrom a second measured concentration of the fluorescent tracer in the permeate stream based on the calibration curve;
- determining an intercept shift for the calibration curve based on comparison of the first measured concentration to the second measured concentration;
- and
- determining an adjusted intercept for the calibration curve based on the intercept shift.
5 more elements
A system comprising:
- a fluorescent tracer pump configured to introduce fluorescent tracer into a feed stream;
- a membrane configured to separate the feed stream into a permeate stream and a concentrate stream;
- a fluorometer configured and positioned to fluorometrically analyze the permeate stream;
- and
- a controller communicatively coupled to the fluorescent tracer pump and the fluorometer, wherein the controller is configured to:
- control the fluorescent tracer pump to introduce the fluorescent tracer into a feed stream to provide a first concentration of fluorescent tracer in the feed stream;
- control the fluorometer to fluorometrically analyze the permeate stream generated from the feed stream having the first concentration of fluorescent tracer and determine therefrom a first measured concentration of the fluorescent tracer in the permeate stream based on a stored calibration curve that includes an intercept;
- control the fluorescent tracer pump to adjust a concentration of the fluorescent tracer introduced into the feed stream to provide a second concentration of fluorescent tracer in the feed stream different than the first concentration;
- control the fluorometer to fluorometrically analyze the permeate stream generated from the feed stream having the second concentration of fluorescent tracer and determine therefrom a second measured concentration of the fluorescent tracer in the permeate stream based on the calibration curve;
- determine an intercept shift for the calibration curve based on comparison of the first measured concentration to the second measured concentration;
- and
- determine an adjusted intercept for the calibration curve based on the intercept shift.
9 more elements
A method of calibrating a fluorometer used to monitor a reverse osmosis membrane separation process comprising:
- introducing a fluorescent tracer into a feed stream;
- contacting a membrane with the feed stream, thereby generating a permeate stream and a concentrate stream;
- terminating the introduction of fluorescent tracer introduced into the feed stream;
- fluorometrically analyzing the permeate stream generated from the feed stream following termination of the fluorescent tracer and determining therefrom a measured concentration of the fluorescent tracer in the permeate stream based on a stored calibration curve that includes an intercept;
- determining an adjusted intercept for the calibration curve of the fluorometer by at least using the measured concentration of the fluorescent tracer as an intercept shift.
2 more elements
A system comprising:
- a fluorescent tracer pump configured to introduce fluorescent tracer into a feed stream;
- a reverse osmosis membrane configured to separate the feed stream into a permeate stream and a concentrate stream;
- a fluorometer configured and positioned to fluorometrically analyze the permeate stream;
- and
- a controller communicatively coupled to the fluorescent tracer pump and the fluorometer, wherein the controller is configured to:
- control the fluorescent tracer pump to introduce a fluorescent tracer into the feed stream;
- subsequently control the fluorescent tracer pump to terminate the introduction of fluorescent tracer introduced into the feed stream;
- control the fluorometer to fluorometrically analyze the permeate stream generated from the feed stream following termination of the fluorescent tracer and determine therefrom a measured concentration of the fluorescent tracer in the permeate stream based on a stored calibration curve that includes an intercept;
- and
- determine an adjusted intercept for the calibration curve of the fluorometer by at least using the measured concentration of the fluorescent tracer as an intercept shift.
7 more elements
A method for calibrating a fluorometer comprising:
- performing a multi-point calibration with a fluorometer, the multi-point calibration comprising fluorometrically analyzing a first fluid substantially devoid of a fluorescent tracer and a second fluid having a known concentration of the fluorescent tracer and determining therefrom a calibration curve for the fluorometer that includes a slope and an intercept;
- subsequent to performing the multi-point calibration, fluorometrically analyzing, with the fluorometer, an aqueous stream in which the fluorescent tracer is introduced at a first concentration level and determining a measured concentration of the fluorescent tracer in the aqueous stream based on the calibration curve;
- adjusting the concentration of fluorescent tracer introduced into the aqueous stream by one of terminating an addition of the fluorescent tracer to the aqueous stream, increasing an amount of the fluorescent tracer added to the aqueous stream, or decreasing the amount of the fluorescent tracer added to the aqueous stream;
- fluorometrically analyzing, with the fluorometer, the aqueous stream following adjustment of the concentration of fluorescent tracer;
- determining an intercept shift for the calibration curve based on fluorometric analysis of the aqueous stream following adjustment of the concentration of fluorescent tracer without determining an adjusted slope for the calibration curve;
- and
- storing an adjusted intercept for the calibration curve compensating for the intercept shift in a non-transitory memory associated with the fluorometer.
4 more elements
Dependencies are inferred from the claim text.