AU697697B2

AU697697B2 - Device for measuring the quantity of flow and the rate of flow of a fluid inside a pipeline

Info

Publication number: AU697697B2
Application number: AU64111/96A
Authority: AU
Inventors: Ralf Greitmann; Adelbert Schalk
Original assignee: Georg Fischer Rohrleitungssysteme AG
Current assignee: Georg Fischer Rohrleitungssysteme AG
Priority date: 1995-07-27
Filing date: 1996-07-29
Publication date: 1998-10-15
Anticipated expiration: 2016-07-29
Also published as: AU6411196A; WO1997005459A1; EP0811147A1

Description

Device for measuring the quantity of flow and the rate of flow of a fluid inside a pipeline The invention relates to a device with an agitator element producing a vortex and a deflection sensor, assigned thereto for the purpose of measuring the quanlity of flow and the rate of flow of a fluid inside a pipeline.

Arran gements of the initially-mentioned type have become known under the term Karman vortex meters. These known arrangements have an agitator element which is provided inside a flow channel and produces a vortex. The vortices cause pressure fluctuations whose frequency is proportional to the flow rate of a fluid. The pressure fluctuations are picked up by a deflection sensor, for example a piezoelement, and are converted into an electrical signal which can be appropriately evaluated for the purpose of determining thie quantity of flow.

In known measuring devices, the agitator element and the deflection •sensor are built into a separate molded element which is provided via connections between two pipeline portions. The later installation, particularly in the case of large nominal widths, into a pipeline which has already beent laid is very costly. Furthermore, the manufacture of the molded 20 elements with a built-in measuring arrangmnent is relatively expensive, particularly when large nominal widths are involved, and also because in the S. case of metal and synthetic pipeline systems there exist, worldwide, varying pipe connection principles and standards, The present invention is a device with an agitator element producing a 25 vortex and with a deflection sensor assigned to same for measuring the quantity of flow of a fluid inside a pipeline, characterised in that the agitator element and the deflection sensor are arranged in a pipe piece mounted at one end of a tubular part and extending at a right angle from same while forming an L-shaped measuring arrangement and insertable into the pipeline via an opening, and therein the agitator element and the deflection sensor are mounted on an insert element exchangeably attached on a support plate, and therein the support plate, which can be attached at the pipeline, closes an opening provided for the purpose of introducing the insert element into the pipeline in a fluid-tight manner.

An advantage of at least some embodiments of the invention is that a simple and cost-efficient device of the initially-mentioned type is created with which already installed pipeline systems may be retrofitted with a device for measuring the quantity of flow and flow rate of the fluid, and that is cost-efficient.

Additional advantageous embodiments can be gathered from the related claims.

By means of the drawings, an example of a preferred embodiment is explained in greater detail, wherein: Figure 1 shows a cross section through a pipeline with an attached support plate and clamp; Figure 2 shows the plan view of the arrangement of Figure 1 without clamp: Figure 3 shows a longitudinal cross-section through a pipeline with an installed measuring device.

A pipeline (10) for transporting a liquid, steam or gas has an opening (12) which is circular in plan view, whose interior rim surface (13) is aligned 20 with the interior wall (17) of a tubular receiving element The tubular receiving element (16) is a component of a support plate (14) and serves for accommodating a cylindrical connecting piece (19) of an insert element (18), which rests with a flanged ring (20) on the receiving element (16) and is releasably attached on same by means of screws Via an annular seal 25 located between the receiving element (16) and the insert element (18).

a fluid-tight connection is created.

At the insert element a deflection sensor directed towards the interior of the pipeline as well as an agitator element (28 or 28') are attached. Here, the agitator element (28) extends with its free and approximately in the middle of the pipeline whereas the agitator element variant penetrates the wall of the pipeline (10) with a threaded part (30) and is secured from the outside by means of a nut For a fluidtight operation, a sealing ring (34) is provided.

The electronics necessary for converting the mechanical oscillations produced at lte deflection sensor (26) into electrical signals are arranged in an electronics housing (36) which is placed on the insert element (18).

In order to secure the support plate wiich rests on the pipeline in a saddle-like manner, laterally projecting flanges (38) with oblong holes (40) or recesses (42) are formed on same. Two brackets whose ends are provided with a thread grip around the pipeline (10) and are placed with their ends into the oblong holes (40) or the recesses Onto the threaded end parts (46) of the brackets tightening nuts (48) for bracing Ihe brackets (44) with the support plate (14) are screwed.

II can be seen in Figure 1 that the interior side (52) of the support plate which rests upon the pipeline is adapted to the pipe curvature in such a way that after the support plate (14) has been mounted it rests against 'i the pipe surface. At the interior surface (44) of the support plate a receiving groove (50) for a seal, which extends around the opening (12) of the pipeline (10) and which can be pressed against the pipeline is also provided.

20 A measuring arrangement (51) for determining the flow rate of a fluid in the pipeline as shown in Figure 3, has a tubular part extending 'to through the opening (12) into the interior of the pipeline at whose one end a pipe piece (54) is mounted which extends away from the tubular part (53) at a right angle and with same forms the L-shaped measuring S 25 arrangement (51).

Into the flow channel (56) formed by the pipe piece (54) extends a piezoelenment (58) serving as a deflection sensor. The piezoelement (58) is inserted in a fluid-tight manner into a synthetic casing (60) which, via an intermnediate annular seal rests in the tubular part (53) with a flange portion (62) of a stop face The piezoelement (58) is electrically connected with an electronics unit (68) arranged in the tubular part A conneclion cable (70) leading away from the electronics unit (68) serves, on the one hand. for the external current supply of the electronics unit and, on the other hand. for relaying a sensor signal which, for example, serves as an oscillation frequency for determining the flow rate of the fluid.

The central axis of the piezoelement (58) is located in the axial direction of the tubular part (53) and divides the flow channel (56) inside the pipe piece (54) into an inlet section and an outlet section for the passing fluid, The ratio a:b is, for example, 2:1, In the flow channel (56) with the fluid flow direction an agitator or vortex element (72) is arranged upstream towards the piezoelement (58).

The tubular part (53) of the measuring arrangement (50) is provided with a nmonting plate resting on the flanged ring (63) of the transition piece wherein the mounting plate is releasably connected via screws (76) with the flanged ring The tubular part (53) inserted into the transition piece (65) rests in a fluid-tight manner via an intermediate annular seal (78) against the interior wall (25) of the tubular connecting piece (27).

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Claims

1. Device with an agitator element producing a vortex and with a deflection sensor assigned to same for measuring the quantity of flow of a fluid inside a pipeline, characterised in that the agitator element and the deflection sensor are arranged in a pipe piece mounted at one end of a tubular part and extending at a right angle from same while forming an L- shaped measuring arrangement and insertable into the pipeline via an opening, and therein the agitator element and the deflection sensor are mounted on the insert element exchangeably attached on a support plate, and therein the support plate, which can be attached at the pipeline, closes an opening provided for the purpose of introduci ig the insert element into the pipeline in a fluid-tight manner.

2. Device in accordance with claim 1, characterized in that the support plate can be mounted on the pipeline by means of at least one bracket gripping around the pipeline.

3. Device in accordance with claim 1 or 2, characterized in that the support plalte can be placed on the pipeline in a saddle-like manner,

4. Device in accordance with claim 2 or 3, characterized in that flanges project laterally from the support plate for the purpose of anchoring the 20 brackets.

Device in accordance with claim 4, characterized in that the brackets have at their ends a thread, which can be freely slid into recesses of the flanges, and the brackets can be braced against the flanges via tightening nuts 2 placed upon the threads. o 25

6. Device in accordance with one of the claims 1-5, characterized in that the insert element has a connecting piece which can be slid into a tubular 4 receiving part of the support plate.

7, Device in accordance with one of the claims 1-6, characterized in that at the support plate a receiving groove for a seal, extending around the opening of' the pipeline, is provided which can be pressed against the pipeline.

8. Device in accordance with claim 1, characterized in that the deflection sensor is located in the axial direction of the tubular part and extends from same into the pipe piece.

9. Device in accordance with claim 8, characterized in that the deflection sensor divides the pipe piece into an inlet section and an outlet section for the flowing fluid, wherein the inlet section has a length with is greater than a length of the outlet section.

10, Device in accordance with claim 9, characterized in that the ratio of the inlet section length to the outlet section length is in the range 1.5:1 to 4:1.

11. Device according to claim 9, characterized in that the ratio of the inlet section length to the outlet section length is substantially 2:1.

12. Device with an agitator element producing a vortex and with a deflection sensor assigned to same for measuring the quantity of flow of a fluid inside a pipeline substantially as hereinbefore described and with reference to the accompanying drawings. Dated this nineteenth day of August 1998 GEORG FISCIER ROHRLEITUNGSSYTEME AG Patent Attorneys for the Applicant: 9" FB RICE CO o 0: to