Fluid momentum detection method and related apparatus

Patent metadata

Field	Value
Publication number	US-10539442-B2
Application number	US-201415316966-A
Country	US
Kind code	B2
Filing date	Jul 1, 2014
Priority date	Jul 1, 2014
Publication date	Jan 21, 2020
Grant date	Jan 21, 2020

Abstract

A method is provided for determining fluid momentum through one or more conduits. The method comprises the step of receiving an elongation signal from an elongation sensor indicating an elongation of the one or more conduits due to the flowing fluid. A momentum term is then calculated.

First claim

What is claimed is:

1. A method for determining fluid momentum through one or more conduits, comprising the steps of:
vibrating at least one of one or more flow tubes in a drive mode vibration;
receiving an elongation signal from an elongation sensor indicating an elongation of the one or more conduits due to a flowing fluid; and
calculating a momentum term based on the elongation signal;
providing a first pickoff and a second pickoff on at least one of the one or more flow tubes;
receiving a first pickoff signal and second pickoff signal by meter electronics from the first pickoff and the second pickoff, respectively, based on a vibrational response to the drive mode vibration;
wherein the meter electronics is configured to:
calculate a difference between the first pickoff signal and second pickoff signal;
determine a mass flow from the pickoff signal difference;
calculate a velocity using the mass flow rate;
calculate a momentum product term by multiplying the velocity and the mass flow rate;
compare the calculated momentum product term with the momentum term; and
indicate a fault if the calculated momentum product term deviates from the momentum term to a degree greater than a predetermined threshold.

2. The method for determining fluid momentum through one or more conduits of claim 1 , wherein calculating the momentum term comprises the step of deriving the momentum term from an axial strain equation comprising

ɛ
y

=

-

F
Ay

A
t

⁢
E

=

+
2

⁢
mv

+

2
⁢

Ap
avg

A
t

⁢
E

,

wherein:
mv is the momentum term;
ε y is the axial strain of the one or more conduits;
F Ay is an anchor force of the one or more conduits;
A t is a cross-sectional area of the one or more conduits;
E is a modulus of elasticity of the one or more conduits;
m is a mass flow rate of the fluid;
v is a fluid velocity of the fluid;
A is a cross-sectional area of the fluid; and
p avg is an average static pressure of the fluid.

3. The method for determining fluid momentum through one or more conduits of claim 1 , further comprising the steps of:
receiving a temperature signal from a temperature sensor; and
calculating a temperature-corrected momentum term.

4. The method for determining fluid momentum through one or more conduits of claim 3 , wherein calculating a temperature-corrected momentum term comprises the step of deriving a temperature-corrected momentum term from an axial strain equation comprising wherein:

ɛ
y

=

-

F
Ay

A
t

⁢
E

=

+
2

⁢
mv

+

2
⁢

Ap
avg

A
t

⁢
E

+

α
T

⁢
Δ
⁢

⁢
T

,

F AY is an anchor force;
mv is the momentum term;
ε y is the axial strain of the one or more conduits;
A t is a cross-sectional area of the one or more conduits;
E is a modulus of elasticity of the one or more conduits;
m is a mass flow rate of the fluid;
v is a fluid velocity of the fluid;
A is a cross-sectional area of the fluid;
p avg is an average static pressure of the fluid;
α T is a coefficient of linear thermal expansion of the one or more conduits; and
ΔT is a change in a temperature of the one or more conduits.

5. The method for determining fluid momentum through one or more conduits of claim 1 , wherein calculating the velocity, v, comprises m=ρA v, wherein:
m is the mass flow rate of the fluid;
ρ is a density of the fluid; and
A is a cross-sectional area of the fluid.

6. The method for determining fluid momentum through one or more conduits of claim 1 , wherein the step of providing an elongation sensor on the one or more conduits proximate a conduit region subjected to momentum re-direction forces, wherein the one or more conduits comprise one or more flow tubes of a vibratory flowmeter, wherein the method comprises the steps of:
receiving a first and second elongation sensor signal from a first and a second elongation sensors, respectively, based on vibrational responses to the drive mode vibrations;
calculating a first momentum term from the first elongation sensor signal, and a second momentum term from the second elongation sensor signal;
comparing the first momentum term to the second momentum term; and
determining the presence of a flow asymmetry between the first and second flow tubes.

7. The method for determining fluid momentum through one or more conduits of claim 6 , further comprising the step of:
indicating a presence of a flow asymmetry if the difference in the first momentum term and second momentum term is greater than a predetermined threshold.

Assignees

• Micro Motion Inc

Inventors

• Weinstein Joel

Classifications

• G01F1/8463

  the measuring conduits' cross-section being deformed during measurement, e.g. by periodically deflecting a portion of the conduits' surface · CPC title

• G01F1/86

  Indirect mass flowmeters, e.g. measuring volume flow and density, temperature or pressure · CPC title

• G01N9/002

  using variation of the resonant frequency of an element vibrating in contact with the material submitted to analysis (G01N9/34 takes precedence) · CPC title

• G01F1/8468

  vibrating measuring conduits · CPC title

• G01F1/206 Primary

  Measuring pressure, force or momentum of a fluid flow which is forced to change its direction · CPC title