Vibrating flowmeter and related methods

Patent metadata

Field	Value
Publication number	US-9976890-B2
Application number	US-201415126346-A
Country	US
Kind code	B2
Filing date	Apr 7, 2014
Priority date	Apr 7, 2014
Publication date	May 22, 2018
Grant date	May 22, 2018

Abstract

A flowmeter is provides that includes a sensor assembly and meter electronics. The flowmeter comprises one or more rigid flow tubes, a driver coupled to the flow tubes that is oriented to induce a drive mode vibration in the flow tubes. Two or more strain gages are coupled to the one or more rigid flow tubes and oriented to sense tension and compression of the flow tubes. One or more bridge circuits is in electrical communication with the two or more strain gages, wherein outputs of the bridge circuits are proportional to a strain detected by at least one of the strain gages.

First claim

What is claimed is:

1. A flowmeter ( 5 ) including a sensor assembly ( 10 ) and a meter electronics ( 20 ), comprising:
one or more rigid flow tubes ( 130 , 130 ′);
a drive mechanism ( 180 ) coupled to the one or more rigid flow tubes ( 130 , 130 ′) and oriented to induce a drive mode vibration in the one or more rigid flow tubes ( 130 , 130 ′);
two or more strain gages ( 200 A-H) coupled to the one or more rigid flow tubes ( 130 , 130 ′) and oriented to sense at least one of a tension and compression in the one or more rigid flow tubes ( 130 , 130 ′);
one or more bridge circuits ( 206 , 206 ′) in electrical communication with the two or more strain gages ( 200 A-H), wherein outputs of the one or more bridge circuits ( 206 , 206 ′) are proportional to a strain detected by at least one of the two or more strain gages ( 200 A-H).

2. The flowmeter ( 5 ) of claim 1 , further comprising a high-pass filter with the meter electronics ( 20 ) to eliminate a DC offset.

3. The flowmeter ( 5 ) of claim 1 , wherein the one or more bridge circuits ( 206 , 206 ′)
electrically subtracts a vibrational response of a first of the two or more strain gages ( 200 A-H) from a vibrational response of a second of the two or more strain gages ( 200 A-H) to yield a voltage having an amplitude A, comprising A=√{square root over (α 1 2 +α 2 2 ±2α 1 α 2 cos(Φ))}, wherein:
α 1 is a first amplitude of the first of the one or more bridge circuits ( 206 , 206 ′) at a drive frequency;
α 2 is a second amplitude of the second of the one or more bridge circuits ( 206 , 206 ′) at the drive frequency; and
Φ is a phase difference between an output of the first of the one or more bridge circuits ( 206 , 206 ′) and the second of the one or more bridge circuits ( 206 , 206 ′).

4. The flowmeter ( 5 ) of claim 1 , wherein a strain gage of the two or more strain gages ( 200 A-H) is coupled to one of the one or more rigid flow tubes ( 130 , 130 ′) and is configured to detect a strain of the one or more rigid flow tubes ( 130 , 130 ′) approximately parallel with the longitudinal axis of the one of the one or more rigid flow tubes ( 130 , 130 ′).

5. The flowmeter ( 5 ) of claim 1 , wherein a strain gage of the two or more strain gages ( 200 A-H) is placed proximate a brace bar ( 140 , 140 ′) so that the strain gage of the two or more strain gages ( 200 A-H) is subjected to approximately a maximum strain amplitude of the rigid flow tubes ( 130 , 130 ′) induced by the drive mode vibration.

6. The flowmeter ( 5 ) of claim 5 , wherein the strain gage of the two or more strain gages ( 200 A-H) is coupled to one of the one or more rigid flow tubes ( 130 , 130 ′) between about 0% and 15% of a distance from the brace bar ( 140 , 140 ′) to a top of the flow tube ( 130 , 130 ′) measured from the brace bar ( 140 , 140 ″) along a vector perpendicular to a flow tube ( 130 , 130 ′) flow direction at the flow tube ( 130 , 130 ′) uppermost portion.

7. The flowmeter ( 5 ) of claim 5 , wherein the strain gage of the two or more strain gages ( 200 A-H) is coupled to one of the one or more rigid flow tubes ( 130 , 130 ′) between about 6% and 9% of a distance from the brace bar ( 140 , 140 ′) to a top of the flow tube ( 130 , 130 ′) measured from the brace bar ( 140 , 140 ″) along a vector perpendicular to a flow tube ( 130 , 130 ′) flow direction at the flow tube ( 130 , 130 ′) uppermost portion.

8. The flowmeter ( 5 ) of claim 1 , wherein the one or more rigid flow tubes ( 130 , 130 ′) comprises at least one of a substantially “U” shape and substantially omega shape.

9. The flowmeter ( 5 ) of claim 1 , further comprising a filter component ( 400 ) disposed between the one or more bridge circuits ( 206 , 206 ′) and meter electronics ( 20 ).

10. The flowmeter ( 5 ) of claim 9 , wherein the filter component comprises:
an amplifier ( 420 );
a high-pass filter ( 430 );
a low pass filter ( 440 ); and
an analog to digital converter (ADC) ( 450 ).

11. The flowmeter ( 5 ) of claim 1 , wherein:
a first strain gage ( 200 A) of the two or more strain gages ( 200 A-H) is coupled to a distal surface ( 131 A) of an inlet leg ( 131 ) of a first flow tube of the one or more rigid flow tubes ( 130 , 130 ′), wherein the first strain gage ( 200 A) is in electrical communication with a first position (R 1 ) of a first bridge circuit ( 206 ) of the one or more bridge circuits ( 206 , 206 ′);
a second strain gage ( 200 B) of the two or more strain gages ( 200 A-H) is coupled to a distal surface ( 134 A) of an outlet leg ( 134 ) of the first flow tube of the one or more rigid flow tubes ( 130 , 130 ′), wherein the second strain gage ( 200 B) is in electrical communication with a first position (R 1 ′) of a second bridge circuit ( 206 ′) of the one or more bridge circuits ( 206 , 206 ′); and
the first and second bridge circuits ( 206 , 206 ′) are in electrical communication with meter electronics ( 20 ).

12. The flowmeter ( 5 ) of claim 1 , wherein:
a first strain gage ( 200 A) of the two or more strain gages ( 200 A-H) is coupled to a distal surface ( 131 A) of an inlet leg ( 131 ) of a first flow tube of the one or more rigid flow tubes ( 130 , 130 ′), wherein the first strain gage ( 200 A) is in electrical communication with a first position (R 1 ) of a first bridge circuit ( 206 ) of the one or more bridge circuits ( 206 , 206 ′);
a second strain gage ( 200 B) of the two or more strain gages ( 200 A-H) is coupled to a distal surface ( 134 A) of an outlet leg ( 134 ) of the first flow tube of the one or more rigid flow tubes ( 130 , 130 ′), wherein the second strain gage ( 200 B) is in electrical communication with a first position (R 1 ′) of a second bridge circuit ( 206 ′) of the one or more bridge circuits ( 206 , 206 ′);
a third strain gage ( 200 G) of the two or more strain gages ( 200 A-H) is coupled to a distal surface ( 131 ′A) of an inlet leg ( 131 ′) of a second flow tube of the one or more rigid flow tubes ( 130 , 130 ′), wherein the third strain gage ( 200 G) is in electrical communication with a third position (R 3 ) of the first bridge circuit ( 206 );
a fourth strain gage ( 200 H) of the two or more strain gages ( 200 A-H) is coupled to a distal surface ( 134 ′A) of an outlet leg ( 134 ′) of the second flow tube of the one or more rigid flow tubes ( 130 , 130 ′), wherein the fourth strain gage ( 200 H) is in electrical communication with a third position (R 3 ′) of the second bridge circuit ( 206 ′); and
the first and second bridge circuits ( 206 , 206 ′) are in electrical communication with meter electronics ( 20 ).

13. The flowmeter ( 5 ) of claim 1 , wherein:
a first strain gage ( 200 A) of the two or more strain gages ( 200 A-H) is coupled to a distal surface ( 131 A) of an inlet leg ( 131 ) of a first flow tube of the one or more rigid flow tubes ( 130 , 130 ′), wherein the first strain gage ( 200 A) is in electrical communication with a first position (R 1 ) of a first bridge circuit ( 206 ) of the one or more bridge circuits ( 206 , 206 ′);
a second strain gage ( 200 B) of the two or more strain gages ( 200 A-H) is coupled to a distal surface ( 134 A) of an outlet leg ( 134 ) of the first flow tube of the one or more rigid flow tubes ( 130 , 130 ′), wherein the second strain gage ( 200 B) is in electrical communication with a first position (R 1 ′) of a second bridge circuit ( 206 ′) of the one or more bridge circuits ( 206 , 206 ′);
a third strain gage ( 200 C) of the two or more strain gages ( 200 A-H) is coupled to a proximal surface ( 131 ′B) of an inlet leg ( 131 ′) of a second flow tube of the one or more rigid flow tubes ( 130 , 130 ′), wherein

Assignees

• Micro Motion Inc

Inventors

• Schollenberger Frederick Scott
• Schlosser Martin Andrew

Classifications

• G01F1/8436

  signal processing · CPC title

• G01F1/8477

  with multiple measuring conduits · CPC title

• G01F1/8427 Primary

  detectors · CPC title

• G01F1/8431

  electronic circuits · CPC title