Coriolis flowmeter having a reduced flag dimension for handling large mass flows

• US 6,776,052 B2
• Filed: 10/29/1999
• Issued: 08/17/2004
• Est. Priority Date: 10/29/1999
• Status: Expired due to Term

• Current Assignee: Micro Motion Incorporated (Emerson Electric Company)
• Original Assignee: Micro Motion Incorporated (Emerson Electric Company)
• Inventors: Crisfield, Matthew T., McCarthy, John Richard
• Primary Examiner(s): Lefkowitz, Edward
• Assistant Examiner(s): Martir, Lilybett
• Application Number:
  US09/430,052
• Publication Number:
  US 20020157479A1
• Time in Patent Office: 1,754 Days
• Field of Search: 738/613.54, 738/613.55, 738/613.56, 738/613.51, 738/613.57
• US Class Current: 73/861.354
• 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 1/8477 with multiple measuring conduits

Abstract

A Coriolis flowmeter sensor capable of handling large mass flow rates and having a reduced flag dimension. In order to have a reduced flag dimension, each of the flow tubes forms a semicircle between an inlet and an outlet. Brace bars, connected to the flow tubes proximate the inlet and outlet, separate the frequencies of vibration in the flow tubes. Pick-offs are positioned on the flow tubes at a position that allows the pickoffs to maximize detection of low amplitude, high frequency vibrations of the flow tubes required to have a reduced flag dimension.

Claims

1. A Coriolis flowmeter having a reduced flag dimension comprising:

a first flow tube having an inlet end and an outlet end, said first flow tube forming substantially a semicircle that begins at said inlet end of said first flow tube and ends at said outlet end of said first flow tube;

a second flow tube having an inlet end and an outlet end, said second flow tube forming substantially a semicircle that begins at said inlet end of said second flow tube and ends at said outlet end of said second flow tube;

a driver affixed to said first flow tube at a point on said first flow tube that is substantially perpendicular to a bending axis of said first flow tube, said driver also affixed to said second flow tube at a point on said second flow tube that is substantially perpendicular to a bending axis of said second flow tube, wherein said driver oscillates said first flow tube and said second flow tube in opposition to each other;

a first brace bar affixed to said first flow tube proximate said inlet end of said first flow tube and affixed to said second flow tube proximate said inlet end of said second flow tube;

a second brace bar affixed to said first flow tube proximate said outlet end of said first flow tube and affixed to said second flow tube proximate said outlet end of said second flow tube; and

pick-offs affixed to said first flow tube and said second flow tube in a position that allows said pick-offs to detect a desired amount of Coriolis force at a low amplitude vibration.

2. The Coriolis flowmeter of claim 1 further comprising:

an inlet manifold affixed to said inlet end of said first flow tube and said inlet end of said second flow tube to affix said first flow tube and said second flow tube to a pipeline.

3. The Coriolis flowmeter of claim 2 further comprising:

a substantially 90 degree bend in a flow path through said inlet manifold.

4. The Coriolis flowmeter of claim 1 further comprising:

an outlet manifold affixed to said outlet end of said first flow tube and said outlet end of said second flow tube to connect said first flow tube and said second flow tube to a pipeline.

5. The Coriolis flowmeter of claim 4 further comprising:

a substantially 90 degree bend in a flow path though said outlet manifold.

6. The Coriolis flowmeter of claim 1 further comprising:

an inlet manifold affixed to said inlet end of said first flow tube and said inlet end of said second flow tube to affix said first flow tube and said second flow tube to a pipeline;

an outlet manifold affixed to said outlet end of said first flow tube and said outlet end of said second flow tube to connect said first flow tube and said second flow tube to said pipeline; and

a spacer affixed to said inlet manifold and said outlet manifold to maintain a fixed distance between said inlet manifold and said outlet manifold.

7. The Coriolis flowmeter of claim 6 wherein said spacer comprises:

an inlet end affixed to said inlet manifold;

an outlet end affixed to said outlet manifold;

a top side, a bottom side, a front side, and a back side each extending between said inlet end of said spacer and said outlet end of said spacer to form a rectangular body; and

openings through said top side of said spacer through which said first flow tube and said second flow tube are affixed to said inlet manifold and said outlet manifold.

8. The Coriolis flowmeter of claim 7 further comprising:

a casing that encloses said first flow tube and said second flow tube affixed to said top side of said spacer.

9. The Coriolis flowmeter of claim 8 wherein said casing comprises:

a front side wall;

a back side wall; and

a mass affixed to said front side wall and said back side wall to change vibrational modes of said casing.

10. The Coriolis flowmeter of claim 1 wherein said position of said pick-offs is substantially 25-50 degrees from said bending axis of said first flow tube and said bending axis of said second flow tube.

11. The Coriolis flowmeter of claim 10 wherein said position of said pick-offs is 30 degrees from said bending axis of said first flow tube and said bending axis of said second flow tube.