WO1993018372A1 - Circuit de mesure de debit et debitmetre - Google Patents
Circuit de mesure de debit et debitmetre Download PDFInfo
- Publication number
- WO1993018372A1 WO1993018372A1 PCT/GB1993/000498 GB9300498W WO9318372A1 WO 1993018372 A1 WO1993018372 A1 WO 1993018372A1 GB 9300498 W GB9300498 W GB 9300498W WO 9318372 A1 WO9318372 A1 WO 9318372A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- flow
- meter
- flowmeter
- resistor
- fluid
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F7/00—Volume-flow measuring devices with two or more measuring ranges; Compound meters
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/05—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects
- G01F1/20—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by detection of dynamic effects of the flow
- G01F1/32—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by detection of dynamic effects of the flow using swirl flowmeters
- G01F1/3227—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by detection of dynamic effects of the flow using swirl flowmeters using fluidic oscillators
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F5/00—Measuring a proportion of the volume flow
Definitions
- This invention relates to a flow circuit for a flow meter which extends the operating range of a flow meter, particularly although not exclusively for gas metering, and to a flow meter incorporating such a circuit.
- the flow meter could be a fluidic flow meter, a vortex shedding meter, a turbine meter etc.
- the useful operating range of a fluidic flowmeter can be limited by the specification of an upper limit to the pressure drop across the meter when operating at its maximum required flowrate. This effectively sets a limit on the maximum meter size. Because the flow meter has a lower limit of operating Reynolds number, below which the meter does not function, fixing the meter size sets a minimum operating flowrate for the meter for a given fluid. There is thus a conflict between the need for a large meter at high flow rates, and a small meter at low flow rates, and one proposed solution is described in GB 2172966 - to have two meters and a valve switching between them - but this is relatively expensive and impractical.
- a basic object of the present invention is to provide a flow circuit and a flow meter in which the operating range is significantly extended.
- a flow circuit for a flow meter comprising a fluid flow line having an upstream junction or a fluid reservoir from which the fluid flow is divided into an inlet stream to a fluidic meter and an inlet stream to a laminar by-pass resistor, and a downstream junction or a fluid reservoir at which an outlet stream from the fluidic meter and an outlet stream from the by-pass resistor are recombined, in which the combined operating characteristics of the junctions and the by-pass resistor are selected and matched to the operating characteristics required of the flow meter, such that the relative magnitude of the two fluid streams changes over the required operating range, whereby, at high fluid flowrate, at the top of the required flow range, the greater proportion of the fluid passes through the by-pass resistor, while at low fluid flowrate, at the bottom of the flow range, the greater proportion of the fluid passes through the fluidic meter.
- a second aspect of the invention is directed to a flow meter incorporating the above defined circuit.
- a flow eter comprising a fluidic meter placed in parallel with a laminar flow by-pass resistor.
- the present invention departs from this teaching and achieves the opposite result by forcing the two flows (by-pass and meter) to change disproportionately, and the choice of two different types of resistance is essential to this principle.
- the flowmeter in accordance with the invention is, most advantageously, automatically self-switching.
- the resistance to fl through the by-pass must be less than that through the meter at high flows but more than the meter at low flows.
- flow resistance in terms of an Euler number defined as pressure drop divided by fluid dynamic head within an element.
- the Euler number of a fluidic flow meter is typically close to unity at the maximum flow condition, rising somewhat as the flowrate decreases.
- a good by-pass resistor requires an Euler number which is low at high flow, but which rises quickly as flowrate decreases.
- Such a characteristic is displayed by parallel plates or by a laminar pipe resistor.
- Use of a bundle of multiple laminar pipe resistors enables the number, diameter and length of such pipes to be optimally selected and matched to the meter.
- Careful design at the inlet and outlet of the resistor to minimize inlet and exit losses at the maximum flow condition may be important. In this respect radial or axial flow diffusion may be employed to reduce exit losses.
- the flow circuit of Figure la comprises a fluid flow line 1 having an upstream junction Jl (or in Fig. lb, the reservoir R), where the flow is divided into two streams 2 and 3, whereby a fraction of the fluid flows as an inlet stream 2 to a fluidic flow meter 4, and the remainder flows as an inlet stream 3 to a laminar by-pass resistor 5. Downstream of these two flow devices 4, 5 the two fluid streams 2A, 3A recombine at downstream junction J2 (or in Fig lc, the reservoir R) , prior to leaving the metering circuit.
- the resistor may for instance consist of a bundle of small tubes or a number of parallel plates to provide the desired laminar flow characteristics
- junctions Jl and J2 are also important in effecting the proportion of by-pass flow.
- the junctions can be designed to bias flow through the by-pass at high flows, by utilising the fluid momentum as either a directed jet or vortex. Any such biasing function will be much reduced at the low flows, where it is unfavourable, due to the increased viscous losses.
- the simplest design for Jl would be a full bore "T" piece, with the side connection to the meter. Forming Jl as a suitable jet pump would incur some extra pressure loss, but assist the bias action.
- the outflow from the resistor could tend to oppose meter flow across a "T"-piece, with the flow out through the side connection.
- a more sophisticated opposed jet with central radial diffusion could be used.
- Another option for J2 is as a form of vortex amplifier with the by-pass flow acting as control of the meter outflow.
- by-pass resistor and fluidic meter could be integrated into a single body.
Landscapes
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- General Physics & Mathematics (AREA)
- Measuring Volume Flow (AREA)
Abstract
Circuit de mesure de débit pour débitmètre comprenant une ligne de débit de fluide possédant une jonction ou réservoir amont où le débit de fluide se trouve divisé en un flux d'entrée vers un appareil de mesure fluidique et un flux d'entrée vers une résistance de dérivation laminaire, et une jonction ou réservoir où un flux de sortie provenant de l'appareil de mesure fluidique et un flux de sortie provenant de la résistance de dérivation sont recombinés. Les caractéristiques de fonctionnement combinées des jonctions (si elles sont présentes) et de la résistance de dérivation sont sélectionnées et adaptées aux caractéristiques de fonctionnement requises du débitmètre, de telle sorte que l'importance relative des deux flux varie dans la plage de fonctionnement requise. Pour un débit élevé, au maximum de la plage de débit requise, la plus grande proportion de fluide passe à travers la résistance de dérivation, alors que pour un faible débit, la plus grande proportion du fluide passe à travers l'appareil de mesure fluidique. L'invention concerne également un débitmètre équipé d'un appareil de mesure fluidique (4) destiné à être placé parallèlement à une résistance de dérivation de débit laminaire (5).
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP93905554A EP0632882A1 (fr) | 1992-03-10 | 1993-03-10 | Circuit de mesure de debit et debitmetre |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB929205190A GB9205190D0 (en) | 1992-03-10 | 1992-03-10 | Flow circuit for a flow meter |
GB9205190.3 | 1992-03-10 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1993018372A1 true WO1993018372A1 (fr) | 1993-09-16 |
Family
ID=10711833
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/GB1993/000498 WO1993018372A1 (fr) | 1992-03-10 | 1993-03-10 | Circuit de mesure de debit et debitmetre |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0632882A1 (fr) |
GB (1) | GB9205190D0 (fr) |
WO (1) | WO1993018372A1 (fr) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0919792A1 (fr) * | 1997-11-28 | 1999-06-02 | Schlumberger Industries | Compteur de volume d'un fluide en écoulement |
WO1999066214A1 (fr) * | 1998-06-17 | 1999-12-23 | Schlumberger Industries, S.A. | Oscillateur fluidique, piece destinee a etre incorporee dans un oscillateur fluidique et procede de fabrication d'un tel oscillateur fluidique |
US20230078572A1 (en) * | 2021-09-14 | 2023-03-16 | Pratt & Whitney Canada Corp. | Methods and devices for measuring mass flow of gaseous fluids |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4461173A (en) * | 1982-05-17 | 1984-07-24 | Sierra Instruments, Inc. | Multirange flowmeter |
EP0129012A1 (fr) * | 1983-06-15 | 1984-12-27 | Mks Instruments, Inc. | Canalisation d'un mouvement laminaire dans des débimètres thermiques et semblables |
US4610162A (en) * | 1984-06-27 | 1986-09-09 | Osaka Gas Company | Fluidic flowmeter |
US4800754A (en) * | 1987-10-07 | 1989-01-31 | Sierra Instruments, Inc. | Wide-range, adjustable flowmeter |
EP0393938A1 (fr) * | 1989-04-18 | 1990-10-24 | Jeavons Engineering Ltd. | Débimètres |
-
1992
- 1992-03-10 GB GB929205190A patent/GB9205190D0/en active Pending
-
1993
- 1993-03-10 WO PCT/GB1993/000498 patent/WO1993018372A1/fr not_active Application Discontinuation
- 1993-03-10 EP EP93905554A patent/EP0632882A1/fr not_active Withdrawn
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4461173A (en) * | 1982-05-17 | 1984-07-24 | Sierra Instruments, Inc. | Multirange flowmeter |
EP0129012A1 (fr) * | 1983-06-15 | 1984-12-27 | Mks Instruments, Inc. | Canalisation d'un mouvement laminaire dans des débimètres thermiques et semblables |
US4610162A (en) * | 1984-06-27 | 1986-09-09 | Osaka Gas Company | Fluidic flowmeter |
US4800754A (en) * | 1987-10-07 | 1989-01-31 | Sierra Instruments, Inc. | Wide-range, adjustable flowmeter |
EP0393938A1 (fr) * | 1989-04-18 | 1990-10-24 | Jeavons Engineering Ltd. | Débimètres |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0919792A1 (fr) * | 1997-11-28 | 1999-06-02 | Schlumberger Industries | Compteur de volume d'un fluide en écoulement |
FR2771813A1 (fr) * | 1997-11-28 | 1999-06-04 | Schlumberger Ind Sa | Compteur de volume d'un fluide en ecoulement |
US6279386B1 (en) | 1997-11-28 | 2001-08-28 | Tokheim Services France | Meter for measuring the volume of a flowing fluid |
WO1999066214A1 (fr) * | 1998-06-17 | 1999-12-23 | Schlumberger Industries, S.A. | Oscillateur fluidique, piece destinee a etre incorporee dans un oscillateur fluidique et procede de fabrication d'un tel oscillateur fluidique |
FR2780110A1 (fr) * | 1998-06-17 | 1999-12-24 | Schlumberger Ind Sa | Oscillateur fluidique, piece destinee a etre incorporee dans un oscillateur fluidique et procede de fabrication d'un tel oscillateur fluidique |
US20230078572A1 (en) * | 2021-09-14 | 2023-03-16 | Pratt & Whitney Canada Corp. | Methods and devices for measuring mass flow of gaseous fluids |
US12085428B2 (en) * | 2021-09-14 | 2024-09-10 | Pratt & Whitney Canada Corp. | Methods and devices for measuring mass flow of gaseous fluids |
Also Published As
Publication number | Publication date |
---|---|
GB9205190D0 (en) | 1992-04-22 |
EP0632882A1 (fr) | 1995-01-11 |
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