Flowmeter fluid composition correction
First Claim
1. A method for compensating the flow measurement of a gaseous fluid of interest for changes in the composition of that fluid in a flowmeter of the microbridge class having a first dynamic microbridge exposed to the flow and producing a flow-related output signal, comprising the steps of:
- obtaining an on-going, uncorrected nulled microbridge sensor output (So) for the fluid of interest;
obtaining an on-going, uncorrected nulled mass flow value (Mo) or volumetric flow value (Vo) for the fluid of interest in relation to the microbridge sensor output;
obtaining the specific heat (cp) thermal conductivity (k) and density (q); and
applying a correction factor normalized with reference to a particular gas to the flowrate signal to obtain the corrected mass flow value (Mo *) or volumetric flow (Vo *) and sensor output So * according to a relationship selected from;
space="preserve" listing-type="equation">M.sub.o */M.sub.o =(k/k.sub.o).sup.X.sbsp.1 (c.sub.p c.sub.po).sup.X.sbsp.2
1 Assignment
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Accused Products
Abstract
A method for correcting the flow measurement of a gaseous fluid of interest for changes in the composition of that fluid in a flowmeter of the microanemometer class is disclosed in which an uncorrected flow value signal for the fluid of interest in relation to a microanemometer sensor output is corrected by applying a correction factor to the flow value signal based on certain unique physical parameters of the fluid of interest which nominally include thermal conductivity, k, specific heat, cp, and density, q.
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Citations
27 Claims
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1. A method for compensating the flow measurement of a gaseous fluid of interest for changes in the composition of that fluid in a flowmeter of the microbridge class having a first dynamic microbridge exposed to the flow and producing a flow-related output signal, comprising the steps of:
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obtaining an on-going, uncorrected nulled microbridge sensor output (So) for the fluid of interest; obtaining an on-going, uncorrected nulled mass flow value (Mo) or volumetric flow value (Vo) for the fluid of interest in relation to the microbridge sensor output; obtaining the specific heat (cp) thermal conductivity (k) and density (q); and applying a correction factor normalized with reference to a particular gas to the flowrate signal to obtain the corrected mass flow value (Mo *) or volumetric flow (Vo *) and sensor output So * according to a relationship selected from;
space="preserve" listing-type="equation">M.sub.o */M.sub.o =(k/k.sub.o).sup.X.sbsp.1 (c.sub.p c.sub.po).sup.X.sbsp.2 - View Dependent Claims (7, 9, 10, 11, 13, 15, 16, 17, 18, 22, 23, 24, 25)
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- 2. or
- space="preserve" listing-type="equation">M.sub.o */M.sub.o =(k/k.sub.o).sup.X.sbsp.1 (c.sub.p c.sub.po).sup.X.sbsp.2 (q/q.sub.o).sup.X.sbsp.3
- View Dependent Claims (8)
- 3. or
- space="preserve" listing-type="equation">V.sub.o */V.sub.o =(k/k.sub.o).sup.z.sbsp.1 (c.sub.p c.sub.po ).sup.z.sbsp.2
- View Dependent Claims (19)
- 4. or
- space="preserve" listing-type="equation">V.sub.o */V.sub.o =(k/k.sub.o).sup.z.sbsp.1 (c.sub.p c.sub.po ).sup.z.sbsp.2 (q/q.sub.o).sup.z.sbsp.3
- 5. and
- space="preserve" listing-type="equation">S.sub.o */S.sub.o =1
- 6. or
- space="preserve" listing-type="equation">S.sub.o */S.sub.o =(k/k.sub.o).sup.Y.sbsp.1 (c.sub.p c.sub.po ).sup.Y.sbsp.2
or
space="preserve" listing-type="equation">S.sub.o */S.sub.o =(k/k.sub.o).sup.Y.sbsp.1 (c.sub.p c.sub.po ).sup.Y.sbsp.2 (q/q.sub.o).sup.Y.sbsp.3Where; M*=corrected mass flow S*=corrected output (sensor) V*=corrected volumetric flow k/ko =normalized thermal conductivity cp /cp o =normalized specific heat q/qo =normalized density o=refers to the base or reference gas x1, x2, x3, or y1, y2, y3 or z1, z2 and z3 are exponents. - View Dependent Claims (12)
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14. A method for compensating the flow measurement of gaseous fluid of interest for changes in the composition of that fluid in a flowmeter having a first dynamic microbridge exposed to the flow and producing a flow-related output signal, comprising the steps of:
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obtaining an on-going, uncorrected, nulled dynamic microbridge sensor output for the fluid of interest; obtaining an on-going, uncorrected nulled mass flow value or volumetric flow value for the fluid of interest in relation to the dynamic microbridge sensor output; obtaining the specific heat (cp) and thermal conductivity (k) of the fluid of interest; and applying an on-going, time-variable correction factor to the flow value normalized with respect to a particular reference gas to obtain the corrected mass flow value or volumetric flow valve and sensor output according to a known relationship, among values of specific heat (cp) and thermal conductivity (k) normalized with respect to the reference gas. - View Dependent Claims (20, 26)
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21. A method for compensating the flow measurement of a gaseous fluid of interest for changes in the composition of that fluid in a flowmeter having a first dynamic microbridge exposed to the flow and producing a flow-related output signal, comprising the steps of:
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obtaining an on-going, uncorrected nulled microbridge sensor output (So) for the fluid of interest; obtaining an on-going, uncorrected nulled mass flow value (Mo) or volumetric flow value (Vo) for the fluid of interest in relation to the microbridge sensor output; obtaining the specific heat (cp) and thermal conductivity (k); and applying a correction factor normalized with respect to a particular reference gas to the flowrate valve to obtain the corrected mass flow value (Mo *) or volumetric flow (Vo *) and sensor output So * according to a relationship selected from;
space="preserve" listing-type="equation">M.sub.o */M.sub.o =(k/k.sub.o).sup.x.sbsp.1.(c.sub.p /c.sub.po).sup.x.sbsp.2
space="preserve" listing-type="equation">V.sub.o */V.sub.o =(k/K.sub.o).sup.z.sbsp.1.(c.sub.p /c.sub.po).sup.z.sbsp.2and
space="preserve" listing-type="equation">S.sub.o */S.sub.o =1
space="preserve" listing-type="equation">S.sub.o */S o=(k/k.sub.o).sup.y.sbsp.1.(c.sub.p /c.sub.po).sup.y.sbsp.2Where; M*=corrected mass flow S*=corrected output (sensor) V*=corrected volumetric flow k/ko=normalized thermal conductivity cp /cpo =normalized specific heat o=refers to the base or reference gas x1, x2, or y1, y2 or z1, and z2 =are exponents. - View Dependent Claims (27)
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Specification