Coriolis mass flow rate/density/viscoy sensor with two bent measuring tubes

• US 6,711,958 B2
• Filed: 04/11/2001
• Issued: 03/30/2004
• Est. Priority Date: 05/12/2000
• Status: Expired due to Term

• Current Assignee: Endress+Hauser Flowtec AG (Endress+Hauser AG)
• Original Assignee: Endress+Hauser Flowtec AG (Endress+Hauser AG)
• Inventors: Koudal, Ole, Schütze, Christian, Bitto, Ennio
• Primary Examiner(s): Lefkowitz, Edward
• Assistant Examiner(s): THOMPSON, JEWEL VERGIE
• Application Number:
  US09/832,751
• Publication Number:
  US 20010037690A1
• Time in Patent Office: 1,084 Days
• Field of Search: 738/613.57, 738/613.55, 738/613.56, 738/613.54
• US Class Current: 73/861.355
• CPC Class Codes: G01F 1/8404 details of flowmeter manufacturing methods
• CPC Class Codes: G01F 1/8409 constructional details
• 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 1/8422 exciters
• CPC Class Codes: G01F 1/8427 detectors
• CPC Class Codes: G01F 1/8477 with multiple measuring conduits
• CPC Class Codes: G01N 2009/006 vibrating tube, tuning fork
• CPC Class Codes: G01N 9/002 using variation of the resonant frequency of an element vibrating in contact with the material submitted to analysis G01N9/34 takes precedence

Abstract

This sensor (10) generates accurate measuring results, for example with an error in the order of 0.5% of the measuring value, hat has mimimized production costs as well as a shorter overall length compared to that of conventional sensors. The sensor has two parallel V shaped measuring tubes (1, 2) each being of one-piece construction. Each tube has a straight inlet portion (11, 21), a straight outlet portion (12, 22), an inlet bend (13, 23) connected with the inlet portion, an outlet bend (14, 24) connected with the outlet portion, a straight tube portion (15, 25) connected with the inlet bend, a straight tube portion (16, 26) connected with the outlet bend, and a vertex bend (17, 27) connected with the first and second straight tube portions. The inlet portions (11, 21) are fixed in an inlet manifold (18) and the outlet portions in an outlet manifold (19); the manifolds (18, 19) are mounted in a support frame (30) which forms part of a housing (3). An excitation arrangement (6) causes the measuring tubes (1, 2) to vibrate as a tuning fork. Interspaced sensor elements (7, 8) are fixed to the measuring tubes. Mounted in the support frame (30) is a feedthrough (37) for a printed-circuit board (96) having conducting tracks (97) to which leads (63, 64, 73, 74, 83, 84) of the excitation system (6) and of the sensor elements (7, 8) are connected.

Claims

1. A Coriolis mass flow rate/density/viscosity sensor designed to be installed in a pipe through which a fluid flows at least temporarily, and comprising:

a first measuring tube bent to a V shape in a first plane symmetrically with respect to a first axis of symmetry;

a second measuring tube bent to a V shape in a second plane symmetrically with respect to a second axis of symmetry,

which measuring tubes are arranged parallel to each other and are each of one-piece construction, and

each of which measuring tubes has

a straight inlet portion with an inlet axis lying in the first plane and second plane, respectively,

a straight outlet portion with an outlet axis lying in the first plane and second plane, respectively, and aligned with the inlet axis,

an inlet bend connected with the inlet portion,

an outlet bend connected with the outlet portion,

a first straight tube portion connected with the inlet bend,

a second straight tube portion connected with the outlet bend, and

a vertex bend connected with the first and second straight tube portions,

which inlet portions are fixed in an inlet manifold, which outlet portions are fixed in an outlet manifold, and

which manifolds are mounted in a support frame which forms part of a housing;

an excitation arrangement

which in operation causes the measuring tubes to vibrate as a tuning fork,

a first portion of which is fixed to the vertex bend of the first measuring tube in the area of the axis of symmetry of the first measuring tube, and

a second portion of which is fixed to the vertex bend of the second measuring tube in the area of the axis of symmetry of the second measuring tube;

a first velocity or displacement sensor,

a first portion of which is fixed to the first straight tube portion of the first measuring tube, and

a second portion of which is fixed to the first straight tube portion of the second measuring tube;

a second velocity or displacement sensor, positioned symmetrically with respect to the axes of symmetry of the measuring tubes,

a first portion of which is fixed to the second straight tube portion of the first measuring tube, and a second portion of which is fixed to the second straight tube portion of the second measuring tube;

a feedthrough mounted in the support frame opposite the vertex bends and containing several electric conductors; and

a printed-circuit board attached to the support frame and extending between the support frame and the vertex bends and having conducting tracks

to which leads of the excitation system and of the velocity or displacement sensors are connected.

2. The Coriolis mass flow rate/density/viscosity sensor as claimed in claim 1 wherein the measuring tubes

are rigidly connected by a first node plate in the vicinity of a location

where the respective inlet portion passes into the respective inlet bend,

are rigidly connected by a second node plate in the vicinity of a location

where the respective inlet bend passes into the respective first straight tube portion,

are rigidly connected by a third node plate in the vicinity of a location

where the respective outlet portion passes into the respective outlet bend, and

are rigidly connected by a fourth node plate in the vicintiy of a location

where the respective outlet bend passes into the respective second straight tube portion.

3. The Coriolis mass flow rate/density/viscosity sensor as claimed in claim 1 wherein electrodynamic velocity sensors are used and the excitation system is of the electrodynamic type.

4. The Coriolis mass flow rate/density/viscosity sensor as claimed in claim 1 wherein

the support frame is of one-piece construction and is made of stainless sheet steel of constant width and thickness having a front face and a rear face, comprises:

a plane inlet frame portion, which has the inlet manifold welded therein,

a plane outlet frame portion, which has the outlet manifold welded therein,

a plane feedthrough frame portion connecting the inlet frame portion and outlet frame portion and having the feedthrough mounted therein in a pressure-tight manner,

a first plane extension frame portion extending from the inlet frame portion at an angle greater than 90°

,

a bent vertex frame portion passing into the first frame portion passing into the first extension frame portion, and

a second plane extension frame portion extending from the outlet frame portion at said angle and passing into the vertex frame portion; and

the support frame is supplemented by a plane front sheet of stainless steel, which is welded to the front, and a plane rear sheet of the same steel, which is welded to the rear face, to form the housing.

5. The Coriolis mass flow rate/density/viscosity sensor as claimed in claim 1 wherein the feedthrough comprises:

a flange attached to the support frame and having a hole;

the printed-circuit board, which is passed through a slot formed in the feedthrough frame portion and extends into the flange, with the printed-circuit board and the slot separated by a distance sufficient for electric isolation;

a disk of insulating material resting on the feedthrough frame portion and through which the printed-circuit board is passed; and

an insulating compound filling a portion of the hole lying above the disk, the insulating compound having a thickness at least equal to the gap length specified for type of protection Ex-d as a function of gap width.

6. The Coriolis mass flow rate/density/viscosity sensor as claimed in claim 2 wherein electrodynamic velocity sensors are used and the excitation system is of the electrodynamic type.

7. The Coriolis mass flow rate/density/viscosity sensor as claimed in claim 2 wherein

the support frame is of one-piece construction and is made of stainless sheet steel of constant width and thickness having a front face and a rear face, comprises:

a plane inlet frame portion, which has the inlet manifold welded therein,

a plane outlet frame portion, which has the outlet manifold welded therein,

a plane feedthrough frame portion connecting the inlet frame portion and outlet frame portion and having the feedthrough mounted therein in a pressure-tight manner,

a first plane extension frame portion extending from the inlet frame portion at an angle greater than 90°

,

a bent vertex frame portion passing into the first frame portion passing into the first extension frame portion, and

a second plane extension frame portion extending from the outlet frame portion at said angle and passing into the vertex frame portion; and

the support frame is supplemented by a plane front sheet of stainless steel, which is welded to the front, and a plane rear sheet of the same steel, which is welded to the rear face, to form the housing.

8. The Coriolis mass flow rate/density/viscosity sensor as claimed in claim 3 wherein

the support frame is of one-piece construction and is made of stainless sheet steel of constant width and thickness having a front face and a rear face, comprises:

a plane inlet frame portion, which has the inlet manifold welded therein,

a plane outlet frame portion, which has the outlet manifold welded therein,

a plane feedthrough frame portion connecting the inlet frame portion and outlet frame portion and having the feedthrough mounted therein in a pressure-tight manner,

a first plane extension frame portion extending from the inlet frame portion at an angle greater than 90°

,

a bent vertex frame portion passing into the first frame portion passing into the first extension frame portion, and

a second plane extension frame portion extending from the outlet frame portion at said angle and passing into the vertex frame portion; and

the support frame is supplemented by a plane front sheet of stainless steel, which is welded to the front, and a plane rear sheet of the same steel, which is welded to the rear face, to form the housing.

9. The Coriolis mass flow rate/density/viscosity sensor as claimed in claim 2 wherein the feedthrough comprises:

a flange attached to the support frame and having a hole;

the printed-circuit board, which is passed through a slot formed in the feedthrough frame portion and extends into the flange, with the printed-circuit board and the slot separated by a distance sufficient for electric isolation;

a disk of insulating material resting on the feedthrough frame portion and through which the printed-circuit board is passed; and

an insulating compound filling a portion of the hole lying above the disk, the insulating compound having a thickness at least equal to the gap length specified for type of protection Ex-d as a function of gap width.

10. The Coriolis mass flow rate/density/viscosity sensor as claimed in claim 3 wherein the feedthrough comprises:

a flange attached to the support frame and having a hole;

the printed-circuit board, which is passed through a slot formed in the feedthrough frame portion and extends into the flange, with the printed-circuit board and the slot separated by a distance sufficient for electric isolation;

a disk of insulating material resting on the feedthrough frame portion and through which the printed-circuit board is passed; and

an insulating compound filling a portion of the hole lying above the disk, the insulating compound having a thickness at least equal to the gap length specified for type of protection Ex-d as a function of gap width.

11. The Coriolis mass flow rate/density/viscosity sensor as claimed in claim 4 wherein the feedthrough comprises:

a flange attached to the support frame and having a hole;

the printed-circuit board, which is passed through a slot formed in the feedthrough frame portion and extends into the flange, with the printed-circuit board and the slot separated by a distance sufficient for electric isolation;

a disk of insulating material resting on the feedthrough frame portion and through which the printed-circuit board is passed; and

an insulating compound filling a portion of the hole lying above the disk, the insulating compound having a thickness at least equal to the gap length specified for type of protection Ex-d as a function of gap width.

12. Coriolis mass flow sensor for measuring a fluid flowing through a pipe, said sensor comprising:

a first tube for conducting the fluid to be measured, said first tube having a single substantially V-shaped tube segment with an inlet-side straight tube portion and an outlet-side straight tube portion, said straight tube portions being in connection via a vertex bend portion of said first tube segment, said V-shaped tube segment being coupled to the pipe via an inlet-side tube segment and an outlet-side tube segment, respectively, during operation, wherein a straight portion of said inlet-side tube segment and a straight portion of said outlet-side tube segment are aligned to each other;

a second tube having a single substantially V-shaped tube segment with an inlet-side straight portion and a outlet-side straight portion, said straight portions being in connection via a vertex bend portion of said second tube segment,

wherein said first and said second tubes are coupled mechanically with each other at an inlet-side location and an outlet-side location, respectively;

an excitation arrangement coupled to said first and said second tubes for vibrating said first and said second tubes; and

a sensor arrangement coupled to said first and said second tubes for detecting inlet-side and outlet-side vibrations of at least one of the tubes.

13. The Coriolis mass flow sensor as claimed in claim 12 wherein the second tube having an inlet-side tube segment being connected with the V-shaped tube segment via whose inlet-side straight tube portion and an outlet-side tube segment being connected with the V-shaped tube segment via whose outlet-side straight tube portion.

14. The Coriolis mass flow sensor as claimed in claim 13 comprising an inlet-side manifold fixed to said inlet-side tube segments of the first and second tubes and an outlet-side manifold fixed to said outlet-side tube segments of the first and second tubes.

15. The Coriolis mass flow sensor as claimed in claim 13 wherein the first and second tubes are shaped in an identical manner.

16. The Coriolis mass flow sensor as claimed in claim 13 wherein the first note plate is affixed to said inlet-side tube segments of the first and second tubes and the second note plate is affixed to said outlet-side tube segments of the first and second tubes.

17. The Coriolis mass flow sensor as claimed in claim 14 wherein the support frame is affixed to the inlet-side and the outlet-side manifolds.

18. The Coriolis mass flow sensor as claimed in claim 12 comprising a first node plate affixed to each of the tubes at said inlet-side location and a second node plate affixed to each of the tubes at said outlet-side location.

19. The Coriolis mass flow sensor as claimed in claim 18 wherein the first node plate is affixed to said inlet-side straight tube portions of the first and the second tubes and the second node plate is affixed to said outlet-side straight tube portions of the first and the second tubes.

20. The Coriolis mass flow sensor as claimed in claim 18 wherein the first note plate is affixed to said inlet-side tube segments of the first and second tubes and the second note plate is affixed to said outlet-side tube segments of the first and second tubes.

21. The Coriolis mass flow sensor as claimed in claim 12 comprising a support frame, said support frame being coupled to said inlet-side tube segment and said outlet-side tube segment of the first tube.

22. The Coriolis mass flow sensor as claimed in claim 21 wherein the support frame is affixed to the inlet-side and the outlet-side manifolds.

23. A support frame of a Coriolis mass flow sensor for measuring a fluid flowing through a piper said sensor having at least one bent measuring tube within the support frame being connectable to said pipe for conducting the fluid to be measured, wherein the support frame is of substantially one-piece construction and comprises:

a substantially plane inlet-side frame portion and a substantially plane outlet-side frame portion, both frame portions being disposed opposite to each other,

a substantially plane feedthrough frame portion having a feedthrough and connecting said inlet-side frame portion and said outlet-side frame portion with each other;

a bent vertex frame portion being connected to said inlet-side frame portion and said outlet-side frame portion and being disposed opposite to said feedthrough frame portion;

wherein the at least one measuring tube is fixed to said inlet-side and said outlet-side frame portions.

24. The support frame as claimed in claim 23 wherein each one of the inlet-side frame portion, the outlet-side frame portion, the feedthrough frame portion, and the bent vertex frame portion having the same width.

25. The support frame as claimed in claim 23 wherein each one of the inlet-side frame portion, the outlet-side frame portion, the feedthrough frame portion, and the bent vertex frame portion having the same thickness.

26. The support frame as claimed in claim 23 wherein an inlet-side manifold is affixed to the inlet-side frame portion and an outlet-side manifold is affixed to the outlet-side frame portion, and wherein each one of a first bent measuring tube and a second bent measuring tube each being connected with said manifolds.

27. The support frame as claimed in claim 23 being supplemented by a front sheet and a rear sheet, said front sheet being affixed to the support frame at a first face of the support frame and said rear sheet being affixed to the support frame at a second face of the support frame.