Coriolis flowmeter with improved zero stability
AssigneeDirect Measurement Corporation
InventorDonald R. Cage
Life of this patent
Estimating the term…
Abstract
A Coriolis mass flowmeter which comprises at least first and second generally parallel flowtubes, each of which includes a first half that is connected to an inlet manifold and a second half that is connected to an outlet manifold, a first brace bar which is attached to the first halves of the flowtubes, and a second brace bar which is attached to the second halves of the flowtubes. The first and second brace bars are oriented on the flowtubes such that, when the flowtubes are vibrated in at least one of a driven mode of vibration and a Coriolis mode of vibration, the resulting reaction forces at the inlet and outlet manifolds are less than those that exist when the first and second brace bars are oriented generally perpendicular to the flowtubes.
Claims11
In combination with a Coriolis mass flowmeter which includes at least first and second generally parallel flowtubes, each of which comprises a first half that is connected to an inlet manifold and a second half that is connected to an outlet manifold, the improvement comprising:
- a first brace bar which is attached to the first halves of the flowtubes;
- and
- a second brace bar which is attached to the second halves of the flowtubes;
- wherein each of the first and second brace bars is oriented on the flowtubes at an angle other than generally perpendicular to the flowtubes;
- wherein when the flowtubes are vibrated in at least one of a driven mode of vibration and a Coriolis mode of vibration, the resulting reaction forces at the inlet and outlet manifolds are less than those that exist when the first and second brace bars are oriented generally perpendicular to the flowtubes.
A Coriolis mass flowmeter which includes:
- at least first and second generally parallel flowtubes, each of which comprises a first half that is connected to an inlet manifold and a second half that is connected to an outlet manifold;
- a first brace bar which is attached to the first halves of the first and second flowtubes;
- a second brace bar which is attached to the second halves of the first and second flowtubes;
- the first halves of the flowtubes comprising a first pair of centerlines defined at the first brace bar;
- the second halves of the flowtubes comprising a second pair of centerlines defined at the second brace bar;
- each brace bar comprising a plane which is defined by at least two principal axes of the brace bar;
- the first brace bar being oriented on the flowtubes such that its plane is inclined at a first angle relative to a first imaginary plane which is perpendicular to the first pair of centerlines;
- and
- the second brace bar being oriented on the flowtubes such that its plane is inclined at a second angle relative to a second imaginary plane which is perpendicular to the second pair of centerlines.
A method for orienting a brace bar on a Coriolis mass flowmeter having at least two flowtubes which each comprise a first half that is connected to an inlet manifold and a second half that is connected to an outlet manifold, the method comprising:
- orienting the brace bar on the first halves of the flowtubes at a number of angles relative to the flowtubes;
- for each angle, determining a set of first reaction forces at the inlet and outlet manifolds which result from vibrating the flowtubes in at least one of a driven mode of vibration and a Coriolis mode of vibration;
- and
- determining an angle for which the first reaction forces are generally minimal.
Dependencies are inferred from the claim text.