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Publication Number
US-10591327-B2
Publication Date
2020-03-17
Expiration Date
Abstract
A method and system for measuring steam mass flow in a conduit by simultaneously measuring absorbance and variable steam patterns by light detectors receiving coherent light.
Core Innovation
The invention measures steam quality and mass flow through a conduit having a longitudinal axis and a predetermined cross sectional area using two coherent beams of light from a first laser and a second laser arranged to pass through the conduit. Light from the first and second coherent beams is detected by corresponding first and second light detectors disposed transverse to the longitudinal axis, with the detectors spaced apart along the longitudinal axis by a predetermined distance. Light absorbance is measured as the difference between the first laser power and the received signal at the first light detector, and the Beer Lambert Law is applied to calculate an average concentration.
The invention determines steam velocity and mass flow by matching patterns in the light detected by the first and second light detectors using cosine similarity. The difference in time between the reception of a pattern or signal detected by the first and second light detectors is measured, and velocity is computed by dividing the difference in time by a predetermined difference distance between the first and second lasers or the predetermined distance between the spaced first and second light detectors. Mass flow is calculated as the product of the concentration, the cross sectional area, and the velocity of the steam.
Two measurement variants are disclosed: one method measures absorbance and matches detected patterns to obtain a time difference, and a second approach additionally uses a compensation factor Z and a beam area to adjust for beam or pipe volume mismatch while still basing concentration on the Beer Lambert Law. The disclosed system versions include reporting the measurements and adjusting a second predetermined time interval by accounting for processing time and repeating the process until completion.
Claims Coverage
The partial content includes three independent method claims and two independent system claims, describing a laser-based measurement approach with three inventive features tied to Beer Lambert Law concentration from absorbance, cosine-similarity pattern matching to obtain a time difference between spaced detectors, and velocity and mass flow computation from the time difference and predetermined distances together with concentration and conduit cross-sectional area.
Two spaced coherent laser beams through conduit with transverse spaced detectors
Passing a first coherent beam of light from a first laser and a second coherent beam of light from a second laser through the conduit, and detecting said first beam with a corresponding first light detector disposed generally transverse to a longitudinal axis of the conduit, with a second light detector spaced apart along the longitudinal axis.
Absorbance measurement and Beer Lambert Law concentration
Measuring light absorbance between said first laser and said first light detector as the difference between the first laser power and the received signal of said first light detector, and calculating the average concentration according to the Beer Lambert Law.
Cosine similarity pattern matching to determine time difference
Matching a pattern by cosine similarity between the light detected by said first and second light detector, and measuring the difference in time between the reception of the pattern detected by the first and second light detector.
Velocity and mass flow calculation from time difference, concentration, and conduit area
Calculating velocity by dividing said predetermined difference distance between said first laser and said second laser by said difference in time, and determining mass flow by the product of said concentration, said cross sectional area and said velocity of the steam.
Time difference from signal receipt by spaced detectors
Determining that the signal detected by the first detector is received by the second detector, and measuring the difference in time between the receipt of the said signal by the first detector and the receipt of the signal by the second detector.
System with pattern matching circuit and reporting with repeat and adjusted time interval
A system comprising a first and a second coherent light beam arranged to pass through a conduit, a first and a second light detector operating for first and second predetermined time intervals, circuitry configured to measure light absorbance, and a pattern matching circuit to compare by cosine similarity the light detected by the first and second light detectors to measure the difference in time, calculating velocity and mass flow using Beer Lambert Law and reporting the measurements, and adjusting the second predetermined time interval by accounting for processing time and repeating the process until completion.
System reporting steam mass flow with beam area and triggering until conclusion
A system comprising at least one source for a first and a second coherent light beam arranged to pass through the conduit with a predetermined distance and at least one coherent light beam having a predetermined area, first and second light detectors operating for first and second predetermined time intervals, detectors configured to measure absorbance and the difference in time between arrival at the first and second detectors, and reporting the steam mass flow from said absorbance, said time difference, said light path distance, said predetermined spacing of said first and second light detectors, said light beam area and said interior diameter of said conduit, with triggering of said coherent light sources and said light detectors and repeating the process until conclusion.
Across the independent claims, the core inventive coverage is directed to measuring steam concentration via absorbance using the Beer Lambert Law, deriving velocity from a time difference obtained by cosine-similarity pattern matching or signal receipt timing between spaced detectors along the conduit longitudinal axis, and computing steam mass flow as a product including the Beer Lambert Law concentration and the conduit cross sectional area, with system embodiments further including reporting and repeating with defined time-interval adjustment or repeated triggering until completion.
Stated Advantages
Reports a performance target for saturated steam (±0.1%).
Documented Applications
No documented applications found
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