Patent US3945253A successfully refreshed from Google Patents.
US3945253A
Expired / Lapsed
US
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Apparatus and method for measuring fluid flow over a wide range of fluid flow conditions and viscosities
Assignee: Individual
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Filing: 1974-03-28
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Granted: 1976-03-23
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Expires: 1994-03-28
Abstract
Abstract Flowmeter apparatus and method for obtaining accurate measurement of fluid flow, not only in the turbulent flow range, but also in the laminar and transitional flow ranges by compensation of the meter reading. The meter reading is also compensated for change in viscosity of the fluid flowing through the meter. The compensation for flow range is based on the best-fit straight line approach obtained by matching straight line segments to the quantity versus frequency output curve throughout the laminar and transitional ranges, and compensating the flowmeter reading in accordance with the shape of the straight line segments. The compensation for change in kinematic viscosity of the fluid is added to the flowmeter output in accordance with the temperature-viscosity relationship for the fluid and in accordance with a ratio of compensation factors between the actual fluid and a reference fluid.
Inventors
- 👤 Frederick F. Liu
- 👤 Arnold E. Liu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:11
CPC Classifications
G; G01; G01F; G01F1/00; G01F1/05; G01F1/10; G01F1/12; G01F1/125
Claims Analysis
Total Claims: 38
Claim 1
Independent Claim
148 words
An apparatus for obtaining a measure of fluid flow rate over the laminar, transitional and turbulent flow range comprising: a turbine flowmeter located in a fluid flow line and producing a frequency output signal variable with flow rate; means for comparing said output signal with a constant reference value to produce a difference signal which is zero throughout the turbulent flow range of the fluid through the flowmeter commencing at frequency (f 1 ); means responsive to said difference signal for producing a compensating signal for compensating said output signal of said flow meter over the laminar and transitional flow ranges for variations from quantities indicated by the straight line function of flow rate versus frequency in the turbulent flow range; and means for combining said compensating signal with said flowmeter output signal to obtain a correct value of flow rate in the laminar and transitional flow ranges.
Claim 2
Independent Claim
148 words
An apparatus for obtaining a measure of fluid flow rate over the laminar, transitional and turbulent flow range comprising: a turbine flowmeter located in a fluid flow line and producing a frequency output signal variable with flow rate; means for comparing said output signal with a constant reference value to produce a difference signal which is zero throughout the turbulent flow range of the fluid through the flowmeter commencing at frequency (f 1 ); means responsive to said difference signal for producing a compensating signal for compensating said output signal of said flow meter over the laminar and transitional flow ranges for variations from quantities indicated by the straight line function of flow rate versus frequency in the turbulent flow range; and means for combining said compensating signal with said flowmeter output signal to obtain a correct value of flow rate in the laminar and transitional flow ranges.
Claim 3
Dependent Claim
28 words
An apparatus as defined in claim 1 wherein: said comparing means includes means for compensating said comparing means for variation in turbulent flow range of a measured fluid.
Claim 4
Dependent Claim
48 words
An apparatus as defined in claim 1 wherein said compensating signal producing means comprises: means for producing said compensating signal with values represented by successive straight line segments matched to the curve of the actual flow rates in the laminar and transitional flow ranges versus said flowmeter output.
Claim 5
Dependent Claim
39 words
An apparatus as defined in claim 1 having means for compensating the flowmeter output with a constant value proportional to the constant slope of the flow rate versus frequency output curve of the flowmeter throughout the turbulent flow range.
Claim 6
Dependent Claim
55 words
An apparatus as defined in claim 1 having means for modifying said compensating signal for changes in viscosity of the flowing fluid; said modifying means comprising means for producing a signal equal to the squared ratio of frequency (f 1 ) of a reference fluid to the frequency f 1 of the flowing fluid ##EQU33##
Claim 7
Dependent Claim
23 words
An apparatus as defined in claim 5 wherein: said combining means comprises a multiplier for multiplying said squared ratio with said compensating signal.
Claim 8
Dependent Claim
69 words
An apparatus as defined in claim 1 wherein: said comparing means includes means for compensating said comparing means for variation in turbulent flow range of a measured fluid; and said compensating signal producing means comprises means for producing said compensating signal with values represented by successive straight line segments matched to the curve of the actual flow rates in the laminar and transitional flow ranges versus said flowmeter output.
Claim 9
Dependent Claim
96 words
An apparatus as defined in claim 1 wherein: said compensating signal producing means comprises means for producing said compensating signal with values represented by successive straight line segments matched to the curve of the actual flow rates in the laminar and transitional flow ranges versus said flowmeter output; means for modifying said compensating signal for changes in viscosity of the flowing fluid; and said modifying means comprising means for producing a signal equal to the squared ratio of frequency (f 1 ) of a reference fluid to the frequency f 1 of the flowing fluid ##EQU34##
Claim 10
Dependent Claim
44 words
An apparatus as defined in claim 8 wherein: said comparing means includes means for compensating said comparing means for variation in turbulent flow range of a measured fluid; and said modifying means comprises a multiplier for multiplying said squared ratio with said compensating signal.
Claim 11
Independent Claim
180 words
An apparatus for obtaining a measure of fluid flow rate over the laminar, transitional and turbulent flow ranges comprising: a turbine flowmeter located in a fluid flowline and producing an output frequency (f) variable with flowrate of the fluid; means for converting said frequency to a voltage signal which increases from zero to selected constant reference voltage over the frequency output range produced during laminar and transitional flow through the flowmeter; means for subtracting said voltage signal from said reference voltage in order to obtain an output voltage which becomes zero at all flowmeter output frequencies above the frequency (f 1 ) at which turbulent flow commences; means responsive to said output voltage for generating a compensating signal for compensating the flowmeter output over the laminar and transitional flow ranges in accordance with the deviation of said frequency output of said flowmeter from a straight line function of flowrate present in the turbulent flow range; and means for combining said compensating signal with said flowmeter output to produce a correct flowmeter output measured throught the laminar and transitional flow ranges.
Claim 12
Independent Claim
180 words
An apparatus for obtaining a measure of fluid flow rate over the laminar, transitional and turbulent flow ranges comprising: a turbine flowmeter located in a fluid flowline and producing an output frequency (f) variable with flowrate of the fluid; means for converting said frequency to a voltage signal which increases from zero to selected constant reference voltage over the frequency output range produced during laminar and transitional flow through the flowmeter; means for subtracting said voltage signal from said reference voltage in order to obtain an output voltage which becomes zero at all flowmeter output frequencies above the frequency (f 1 ) at which turbulent flow commences; means responsive to said output voltage for generating a compensating signal for compensating the flowmeter output over the laminar and transitional flow ranges in accordance with the deviation of said frequency output of said flowmeter from a straight line function of flowrate present in the turbulent flow range; and means for combining said compensating signal with said flowmeter output to produce a correct flowmeter output measured throught the laminar and transitional flow ranges.
Claim 13
Dependent Claim
57 words
An apparatus as defined in claim 10 wherein: said generating means produces a compensating signal which is a function of the ratio of the constant slope G o of the flowrate versus frequency curve during turbulent flow and the deviation from said constant slope ΔG with frequency during laminar and transitional flow ranges, said function being ##EQU35##
Claim 14
Dependent Claim
35 words
An apparatus as defined in claim 11 wherein: said generating means comprises a dioderesistor function generator for producing a value of said ratio as a function of frequency over the laminar and transitional flow ranges.
Claim 15
Dependent Claim
87 words
An apparatus as defined in claim 12 wherein: said function generator comprises means for producing a plurality of successive straight line segments closely approximating the curve of ΔG versus frequency over the laminar and transitional flow ranges; said producing means comprising the combination of a number of diode-resistor circuits; a variable resistor bias for each diode for controlling the frequency range over which each diode will conduct; and each resistor in said circuits being variable for controlling the slope of the line segment produced by each circuit.
Claim 16
Dependent Claim
50 words
An apparatus as defined in claim 11 wherein: said converting means comprises means for varying the frequency output (f 1 ) at which said voltage signal reaches said selected constant referenced voltage; said frequency (f 1 ) corresponding to the frequency output at the start of the turbulent flow range.
Claim 17
Dependent Claim
40 words
An apparatus as defined in claim 14 having: means for compensating the flowmeter output with a constant value A/G o which is proportional to the intercept A of said curve and inversely proportional to said constant slope G o .
Claim 18
Dependent Claim
62 words
An apparatus as defined in claim 10 wherein said converting means comprises: a diode pump circuit, a variable resistance in said circuit, the value of said resistance determining the frequency output (f 1 ) at which said voltage signal reaches said selected constant value; said frequency (f 1 ) corresponding to the frequency output at the start of the turbulent flow range.
Claim 19
Dependent Claim
29 words
An apparatus as defined in claim 16 having a zener diode for limiting the maximum output of said diode pump circuit to a value corresponding to said reference voltage.
Claim 20
Dependent Claim
45 words
An apparatus as defined in claim 10 having means for compensating the flowmeter output with a constant value A/G o which is proportional to the intercept A and inversely proportional to said constant slope G o of the flowrate versus frequency curve for turbulent flow.
Claim 21
Dependent Claim
37 words
An apparatus as defined in claim 10 having: means for compensating for changes in viscosity of the fluid in said flow line, said means comprising means for adjusting said converting means for varying frequency (f 1 ).
Claim 22
Dependent Claim
68 words
An apparatus as defined in claim 19 having: means for producing a signal equal to the squared ratio of frequency (f 1 ) of a reference fluid to frequency (f 1 ) of the flowing fluid ##EQU36## and means for combining said squared ratio signal with said compensating signal in order to compensate the flowmeter output in the laminar and transitional flow ranges for variations in fluid viscosity.
Claim 23
Dependent Claim
23 words
An apparatus as defined in claim 20 wherein: said combining means comprises a multiplier for multiplying said squared ratio with said compensating signal.
Claim 24
Dependent Claim
82 words
An apparatus as defined in claim 10 wherein: said generating means produces a compensating signal which is a function of the ratio of the constant slope G o of the flowrate versus frequency curve during turbulent flow and the deviation from said constant slope ΔG with frequency during laminar and transitional flow ranges, said function being ##EQU37## and means for compensating the flowmeter output with a constant value A/G o proportional to said constant slope, A representing the intercept of said curve.
Claim 25
Dependent Claim
37 words
An apparatus as defined in claim 22 wherein: means for compensating for changes in viscosity of the fluid in said flow line, said means comprising means for adjusting said converting means for varying frequency (f 1 ).
Claim 26
Dependent Claim
68 words
An apparatus as defined in claim 23 wherein: means for producing a signal equal to the squared ratio of frequency (f 1 ) of a reference fluid to frequency (f 1 ) of the flowing fluid ##EQU38## and means for combining said squared ratio signal with said compensating signal in order to compensate the flowmeter output in the laminar and transitional flow ranges for variations in fluid viscosity.
Claim 27
Dependent Claim
23 words
An apparatus as defined in claim 24 wherein: said combining means comprises a multiplier for multiplying said squared ratio with said compensating signal.
Claim 28
Independent Claim
123 words
A method for obtaining a measurement of fluid flowrate over the laminar, transitional and turbulent flow ranges comprising the steps of: obtaining a frequency output signal from a turbine flowmeter which is variable with flowrate; comparing said output signal with constant reference value to obtain a difference signal which reduces to zero at the start of the turbulent flow range and remains zero throughout the turbulent range; and compensating said difference signal with signal which represents the difference in actual flow rate in the laminar and transitional flow ranges from the flow rate indicated by the straight line function of flow rate versus frequency in the turbulent flow range, the compensated signal represented the actual flowrate in the laminar and transitional flow regions.
Claim 29
Independent Claim
123 words
A method for obtaining a measurement of fluid flowrate over the laminar, transitional and turbulent flow ranges comprising the steps of: obtaining a frequency output signal from a turbine flowmeter which is variable with flowrate; comparing said output signal with constant reference value to obtain a difference signal which reduces to zero at the start of the turbulent flow range and remains zero throughout the turbulent range; and compensating said difference signal with signal which represents the difference in actual flow rate in the laminar and transitional flow ranges from the flow rate indicated by the straight line function of flow rate versus frequency in the turbulent flow range, the compensated signal represented the actual flowrate in the laminar and transitional flow regions.
Claim 30
Dependent Claim
26 words
A method as defined in claim 26 including the step of: compensating the difference signal for variation in the output signal at which turbulent flow commences.
Claim 31
Dependent Claim
35 words
A method as defined in claim 27 wherein: the compensating of said difference signal includes producing with a function generator simultaneously successive straight line segments matching a plot of said flow rate difference against frequency.
Claim 32
Dependent Claim
25 words
A method as defined in claim 28 including the step of: modifying said compensating signal with a signal which is a function of fluid viscosity.
Claim 33
Dependent Claim
39 words
A method as defined in claim 29 wherein: said viscosity signal is the squared ratio of output signal of a reference fluid to the output signal of the flowing fluid ##EQU39## corresponding to the condition when turbulent flow commences.
Claim 34
Dependent Claim
20 words
A method as defined in claim 30 comprising the step of: multiplying the squared ratio with the modified compensating signal.
Claim 35
Dependent Claim
30 words
A method as defined in claim 26 including the step of: compensating the difference signal with a constant signal value proportional to the constant slope of said straight line function.
Claim 36
Dependent Claim
60 words
A method as defined in claim 26 including the step of: compensating the difference signal for variation in the output signal at which turbulent flow commences; compensating the difference signal with a constant signal value proportional to the constant slope of said straight line function; and modifying said compensating signal with a signal which is a function of fluid viscosity.
Claim 37
Independent Claim
141 words
An apparatus for obtaining a measure of fluid flow rate over the laminar, transitional and turbulent flow range comprising: a flowmeter located in a fluid flow line and producing an output signal variable with flow rate; means for comparing said output signal with a constant reference value to produce a different signal which is zero throughout the turbulent flow range of the fluid through the flowmeter; means responsive to said difference signal for producing a compensating signal for compensating said output signal of said flow meter over the laminar and transitional flow ranges for variations from quantities indicated by the straight line function of flow rate versus output signal in the turbulent flow range; and means for combining said compensating signal with said flowmeter output signal to obtain a correct value of flow rate in the laminar and transitional flow ranges.
Claim 38
Independent Claim
141 words
An apparatus for obtaining a measure of fluid flow rate over the laminar, transitional and turbulent flow range comprising: a flowmeter located in a fluid flow line and producing an output signal variable with flow rate; means for comparing said output signal with a constant reference value to produce a different signal which is zero throughout the turbulent flow range of the fluid through the flowmeter; means responsive to said difference signal for producing a compensating signal for compensating said output signal of said flow meter over the laminar and transitional flow ranges for variations from quantities indicated by the straight line function of flow rate versus output signal in the turbulent flow range; and means for combining said compensating signal with said flowmeter output signal to obtain a correct value of flow rate in the laminar and transitional flow ranges.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-03-23 | 1979-09-22 | 1980-03-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-03-23 | 1983-09-22 | 1984-03-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-03-23 | 1987-09-22 | 1988-03-23 | $7700.00 | Window Closed / Lapsed |