Apparatus and method for continuously measuring mass flow
First Claim
1. An apparatus for measuring mass flow of a fluid flow, comprising:
- a pair of straight parallel conduits each having opposite ends, as well as an axis and a mid-point between said opposite ends;
support means connected to said conduits for holding said opposite ends at substantially fixed positions;
connector means connected to said support means for supplying a fluid flow whose mass flow rate is to be measured to said pair of parallel conduits, each conduit receiving about one half of the fluid flow at one end of said support means and recombining said fluid flow at the other end of said support means;
drive means associated with said conduits for oscillating said conduits towards and away from each other at a selected frequency in a direction transverse to their respective axis and substantially at their respective mid-point; and
at least one sensor for sensing motion of said conduits at a sensing point spaced from each mid-point and from said opposite ends for sensing any phase difference of the selected frequency between said parallel conduits.
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Accused Products
Abstract
An apparatus and method for measuring mass flow rate utilizes a pair of parallel conduits having fixed ends. A driving mechanism is connected between the conduits near their mid-point for applying transverse oscillations to the conduits at a selected frequency. The fluid whose mass flow rate is to be measured is divided roughly equally and supplied through the parallel conduits. A motion sensor upstream of the driving mechanism and another one downstream of the driving mechanism produce signals which have the same frequency as the driving frequency but which lead or lag the driving frequency with regard to phase. This difference is phase is a measurement of mass flow rate.
56 Citations
10 Claims
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1. An apparatus for measuring mass flow of a fluid flow, comprising:
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a pair of straight parallel conduits each having opposite ends, as well as an axis and a mid-point between said opposite ends; support means connected to said conduits for holding said opposite ends at substantially fixed positions; connector means connected to said support means for supplying a fluid flow whose mass flow rate is to be measured to said pair of parallel conduits, each conduit receiving about one half of the fluid flow at one end of said support means and recombining said fluid flow at the other end of said support means; drive means associated with said conduits for oscillating said conduits towards and away from each other at a selected frequency in a direction transverse to their respective axis and substantially at their respective mid-point; and at least one sensor for sensing motion of said conduits at a sensing point spaced from each mid-point and from said opposite ends for sensing any phase difference of the selected frequency between said parallel conduits. - View Dependent Claims (2, 3)
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4. A method for measuring mass flow rate of a fluid flow, comprising:
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oscillating mid-points of a pair of straight parallel conduits towards and away from each other at a selected frequency while holding opposite ends of the conduits substantially fixed; passing about one half of a fluid flow whose mass flow rate is to be measured through each of the conduits; sensing motion of each conduit at a first sensing location spaced from the mid-points of the conduits and from the opposite ends of the conduits; and measuring a phase difference between the selected frequency of oscillation at said mid-points and the measured motion at said first sensing location induced in said pair of parallel conduits, which measurement corressponds to the mass flow rate of the fluid flow. - View Dependent Claims (5)
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6. An apparatus for measuring mass flow of a fluid flow, comprising:
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a pair of straight parallel conduits each having opposite ends, as well as an axis and a mid-point between said opposite ends; support means connected to said conduits for holding said opposite ends at substantially fixed positions; connector means connected to said support means for supplying a fluid flow whose mass flow rate is to be measured to said pair of parallel conduits, each conduit receiving about one half of the fluid flow; drive means associated with said conduits for oscillating said conduits at a selected frequency in a direction transverse to their respective axis and substantially at their respective mid-points including a solenoid coil connected to one of said pair of conduits at its mid-point and a permanent magnet connected to the other of said pair of conduits at its mid-point and movable in said coil, as well as current means connected to said solenoid coil for applying current to said solenoid coil at said selected frequency for oscillating said conduits; at least one sensor for sensing motion of said conduits at a sensing point spaced from each mid-point and from said opposite ends; and a second sensor for sensing motion of said conduits at a second sensing point spaced from each mid-point and on a side of each mid-point opposite from said first mentioned sensing point, said first mentioned sensing point being upstream of each mid-point with respect to a direction of fluid flow and said second sensing point being downstream of each mid-point with respect to said direction, motion at said first mentioned sensing point lagging said selected frequency with respect to phase and motion at said second sensing point leading said selected frequency with respect to phase, said lead and lag of phase corresponding to mass flow rate of the fluid flow. - View Dependent Claims (7, 8, 9, 10)
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Specification