Inertia force flowmeter

• US 5,663,509 A
• Filed: 09/05/1995
• Issued: 09/02/1997
• Est. Priority Date: 09/01/1994
• Status: Expired due to Fees

• Current Assignee: Hyok S. Lew, Yon S. Lew
• Original Assignee: Hyok S. Lew, Yon S. Lew
• Inventors: Lew, Yon S., Lew, Hyok S.
• Primary Examiner(s): Chilcot, Richard
• Assistant Examiner(s): Artis, Jewel V.
• Application Number:
  US08/523,811
• Time in Patent Office: 728 Days
• Field of Search: 73/861.355, 73/861.356, 73/861.357
• US Class Current: 73/861.357
• CPC Class Codes: G01F 1/8413 means for influencing the flowmeter's motional or vibrational behaviour, e.g., conduit support or fixing means, or conduit attachments
• CPC Class Codes: G01F 1/8436 signal processing
• CPC Class Codes: G01F 1/8454 rotating or rotatingly suspended measuring conduits
• CPC Class Codes: G01F 1/8472 having curved measuring conduits, i.e. whereby the measuring conduits' curved center line lies within a plane G01F1/8481 takes precedence
• CPC Class Codes: G01F 1/8477 with multiple measuring conduits
• CPC Class Codes: G01F 1/8486 with multiple measuring conduits
• CPC Class Codes: G01F 1/8495 with multiple measuring conduits

Abstract

An inertia force flowmeter comprises at least one conduit (1), an electromagnetic vibrator (11) generating a transverse reciprocating motion of the conduit (1) and a pair of differential pressure sensors (12 and 13) detecting the fluid pressure gradient in directions parallel to the directions of the transverse reciprocating motion of the conduit (1) respectively at two different sections of the conduit (1), wherein the mass flow rate is determined as a function of phase difference between two alternating electrical signals respectively provided by the two differential pressure sensors (12 and 13).

Claims

1. An apparatus for measuring flow rate of fluid media moving through at least one conduit under a transverse reciprocating motion, comprising in combination:

a) at least one conduit providing a flow passage;

b) means for generating a transeverse reciprocating motion of the conduit in directions substantially perpendicular to a reference plane defined by the center line of the conduit in a mode wherein amplitude of the transverse reciprocating motion of the conduit has a minimum value at two opposite extremities respectively connected to an inlet leg and an outlet leg and has a maximum value at a center section of the conduit;

c) a first differential pressure transducer means for detecting a fluid pressure gradient in directions parallel to directions of the transverse reciprocating motion of the conduit at a first section of the conduit located on one side of the center section of the conduit, and generating a first alternating electrical signal representing the fluid pressure gradient existing at the first sedition of the conduits

d) a second differential pressure transducer means for detecting a fluid pressure gradient in directions parallel to directions of the transverse reciprocating motion of the conduit at a second section of the conduit located on the other side of the center section of the conduit opposite to said one side, and generating a second alternating electrical signal representing the fluid pressure gradient existing at the second section of the conduit; and

e) means for determining an electrical variable related to a phase difference between the first and second alternating electrical signals as a measure of mass flow rate of fluid media moving through the conduit.

2. An apparatus as defined in claim 1 including means for determining the mass flow rate of fluid media moving through the conduit as a function of the electrical variable related to the phase difference.

3. An apparatus as defined in claim 1 wherein the conduit is curved in a relationship wherein the center line of the conduit lies substantially on a reference plane approximately perpendicular to the directions of the transverse reciprocating motion of the conduit.

4. An apparatus as defined in claim 3 wherein the two opposite extremities of the conduit are respectively connected to the inlet and outlet legs by conduit coupling means allowing at least a minimal amount of pivotal movement of the conduit bout a pivotal axis lying on the reference plane.

5. An apparatus as defined in claim 1 wherein the conduit is substantially straight.

6. An apparatus as defined in claim 2 wherein said means for determining mass flow rate determines the mass flow rate of fluid media as a product of a parameter representing an amplitude of fluctuation in the fluid a pressure gradient and the function of the electrical variable related to the phase difference.

7. An apparatus as defined in claim 2 wherein said means for determining mass flow rate determines the mass flow rate of fluid media as a product of a ratio of a parameter representing an amplitude of fluctuation in the fluid pressure gradient to frequency of the transverse reciprocating motion of the conduit and the function of the electrical variable related to the phase difference.

8. An apparatus as defined in claim 2 wherein said means for determining mass flow rate determines the mass flow rate of fluid media as a product of a ratio of frequency of the transverse reciprocating motion of the conduit times a conduit parameter representing an amplitude of fluctuation in the fluid pressure gradient to square of amplitude of velocity in the transverse reciprocating motion of the conduit and the function of the electrical variable related to the phase difference.

9. An apparatus as defined in claim 1 including another conduit providing another flow passage, wherein said at least one conduit and said another conduit have substantially identical construction and are disposed in a superimposing relationship with a space therebetween in a mirror image to one another with respect to a reference plane located therebetween;

and said means for generating a transverse reciprocating motion generates a relative transverse reciprocating motion between said at least one conduit and said another conduit, said first and said second differential pressure transducer means detect the fluid pressure gradient existing in the fluid media contained within at least one of said at least one conduit and said another conduit, and said at least one conduit and said another conduit connect the inlet leg and the outlet leg to one another in one of the parallel connection and series connection.

10. An apparatus as defined in claim 9 including means for determining mass flow rate of fluid media moving through it least one of said at least one conduit and said another conduit as a function of the electrical variable related to the phase difference.

11. An apparatus as defined in claim 9 wherein each of said least one conduit and said another conduit is curved in a relationship wherein the center line of each conduit lies on a plane substantially parallel to a reference plane located intermediate said at least one conduit and said another conduit.

12. An apparatus as defined in claim 11 wherein the two opposite extremities of each of said at least one conduit and another conduit are respectively connected to the inlet leg and the outlet leg of each conduit by conduit coupling means allowing at least a minimal amount of pivotal movement of each conduit about a pivotal axis of each conduit parallel to the reference plane.

13. An apparatus as defined in claim 9 wherein each of said at least one conduct and said another conduit is substantially straight.

14. An apparatus as defined in claim 10 wherein said means for determining mass flow rate determines the mass flow rate of fluid media as a product of a parameter representing an amplitude of fluctuation in the fluid pressure gradient and the function of the electrical variable related to the phase difference.

15. An apparatus as defined in claim 10 wherein said means for determining mass flow rate determines the mass flow rate of fluid media as a product of a ratio of a parameter representing an amplitude of fluctuation in the fluid pressure gradient to frequency of the relative transverse reciprocating motion between said at least one conduit and said another conduit and the function of the electrical variable related to the phase difference.

16. An apparatus as defined in claim 10 wherein said means for determining mass flow rate determines the mass flow rate of fluid media as a product of a ratio of frequency of the relative transverse, reciprocating motion between said at least one conduit and said another conduit times a parameter representing an amplitude of fluctuation in the fluid pressure gradient to square of amplitude of velocity in the relative transverse reciprocating motion between said at least one conduit and said another conduit and the function of the electrical variable related to the phase difference.

17. An apparatus for measuring flow rate of media moving through least one conduit under a transverse reciprocating motion, comprising in combination:

a) at least one conduit providing a flow passage;

b) means for generating a transverse reciprocating motion of the conduit in directions substantially perpendicular to a reference plane defined by the center line of the conduit in a mode wherein amplitude of the transverse reciprocating motion of the conduit has a minimum value at two opposite extremities respectively connected to an inlet leg and an outlet leg and has a maximum value at a center section of the conduit;

c) a first vibratory motion transducer means for detecting the transverse reciprocating motion of the conduit at a first section of the conduit located on one side of the center section of the conduit, and generating a first alternating electrical signal representing the transverse reciprocating motion of the conduit occurring at the first section of the conduit;

d) a second vibratory motion transducer means for detecting the transverse reciprocating motion of the conduit at a second section of the conduit located on the other side of the center section of the conduit opposite to said one side, and generating a second alternating electrical signal representing the transverse reciprocating motion of the conduit occurring at the second section of the conduit;

e) means for obtaining a phase difference between the first and second alternating electrical signals; and

f) means for measuring amplitude of fluctuation in fluid pressure gradient in directions parallel to directions of the transverse reciprocating motion of the conduit at a section of the conduit; and

g) means for determining mass flow rate of fluid media moving through the conduit as a product of a parameter representing the amplitude of fluctuation in fluid pressure gradient and a function of an electrical variable related to the phase difference between the first and second alternating electrical signals.

18. An apparatus as defined in claim 17 wherein said means for determining mass flow rate determines the mass flow rate of fluid media as a product of a ratio of the parameter representing the amplitude of fluctuation in fluid pressure gradient to frequency of the transverse reciprocating motion of the conduit arid the function of the electrical variable related to the phase difference.

19. An apparatus as defined in claim 17 including another conduit providing another flow passage, wherein said at least one conduit and said another conduit have substantially identical construction and are disposed in a superimposing relationship with a space therebetween in a mirror image to one another with respect to a reference plane located therebetween;

and said means for generating the transverse reciprocating motion generates a relative transverse reciprocating motion between said at least one conduit and said another conduit, said first and second vibratory motion transducer means detect the relative transverse reciprocating motion between said at least one conduit and said another conduit, and said at least one conduit and said another conduit connect the inlet leg and the outlet leg to one another in one of the parallel and series connection.

20. An apparatus as defined in claim 19 wherein said means for determining mass flow rate determines the mass flow rate of fluid media moving through at least one of said at least one conduit and said another conduit as a product of a ratio the parameter representing the amplitude of fluctuation in fluid pressure gradient to frequency of the relative transverse reciprocating motion between said at least one conduit and another conduit and the function of the electrical variable related to the phase difference.