Self-calibrating open-channel flowmeter
First Claim
1. Fluid velocity measuring apparatus for indicating the average rate of fluid flow in an open-channel conduit, comprising:
- (a) sensor means for producing local depth (DS) and local velocity (VS) signals at a given open-channel site;
(b) memory means (56) for storing a plurality of sets of reference depth (DR) and reference velocity (VR) signals corresponding to a plurality of flow coefficients (CF) each of which is representative of the ratio between averaged to sensed velocity, respectively;
(c) comparison means (58) responsive to said local depth and local velocity signals and to said reference depth and reference velocity signals for selecting the corresponding flow coefficient (CF), respectively; and
(d) first multiplier means (64) for multiplying said local velocity signal and said flow coefficient, thereby to produce an average velocity signal (V).
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Accused Products
Abstract
An open-channel flowmeter is calibrated by the use of local velocity and level characteristics existing at a given site, as measured by the flowmeter itself. Stored reference relationships that have been either theoretically or experimentally derived are compared to the velocity level relationships at any particular site so as to determine a correction factor which is valid at that site so as to modify the sensed velocity to be an accurate approximation of the average velocity under those site conditions. A local velocity signal is modified so as to make it an accurate approximation of the mean velocity for open-channel flowmeters of the level/velocity type.
55 Citations
15 Claims
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1. Fluid velocity measuring apparatus for indicating the average rate of fluid flow in an open-channel conduit, comprising:
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(a) sensor means for producing local depth (DS) and local velocity (VS) signals at a given open-channel site; (b) memory means (56) for storing a plurality of sets of reference depth (DR) and reference velocity (VR) signals corresponding to a plurality of flow coefficients (CF) each of which is representative of the ratio between averaged to sensed velocity, respectively; (c) comparison means (58) responsive to said local depth and local velocity signals and to said reference depth and reference velocity signals for selecting the corresponding flow coefficient (CF), respectively; and (d) first multiplier means (64) for multiplying said local velocity signal and said flow coefficient, thereby to produce an average velocity signal (V). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. The method for measuring the flow rate of fluid flowing in an open-channel conduit, comprising:
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(a) generating a plurality of sets of reference depth (DR) and reference velocity (VR) signals corresponding to a plurality of flow coefficients (CF) each of which is representative of the ratio between average velocity to sensed velocity, respectively (b) storing said flow coefficients in a signal comparison means; (c) supplying the sensed depth (DS) and velocity (VS) signals to said comparison means to produce a corresponding flow coefficient (CF) from said storage means; and (d) multiplying said corresponding flow coefficient with said sensed velocity signal thereby to produce average velocity (V). - View Dependent Claims (12, 13, 14, 15)
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Specification