DE102015120730A1 - Magnetic-inductive flowmeter and assembly comprising a pipeline and a magnetic-inductive flowmeter - Google Patents

Abstract

A magnetic-inductive flowmeter (1) for detecting a flow rate and / or a flow rate of a flowable medium, comprising a base body which has a magnet system with at least two coil systems (3, 4), and at least two measuring electrodes (8) for tapping a measuring signal characterized in that the base body (15) is formed as a ring with a medium-contacting annular inner surface (16), and that the magnetic-inductive flowmeter (1) has a locking element or a plurality of locking elements (11), which or which with the main body (15) are connected and which of an outer contour (17) of the base body (15) are extendable and an arrangement comprising a conduit (2) for guiding a flowable medium and a magnetic-inductive flowmeter (1).

Description

The present invention relates to a magnetic-inductive flowmeter according to the preamble of claim 1 and an arrangement comprising a pipeline and a magnetic-inductive flowmeter according to the preamble of claim 3.

The most common magnetic-inductive flowmeters have a pressure-stable metallic measuring tube with terminal flanges, which is usually equipped with an electrically insulating liner. Around the measuring tube are then the components of the electromagnetic flowmeter, so solenoid coils and measuring electrodes, and possibly other components such as return plates, pole pieces, wiring, an evaluation and the like arranged.

A not insignificant cost and material factor plays thereby the measuring tube itself. This can for example consist of steel and has a corresponding weight, whereby it comes during transport and during installation with increasing nominal size to difficulties in handling due to the high weight.

In addition, an existing pipeline is interrupted to insert the measuring tube. Particular requirements are placed on the tightness at the joints between the measuring tube and pipe, which are usually realized via flange.

Furthermore, measuring tubes made of plastic material are known from the prior art. A corresponding measuring device is eg in the DE 10 2013 102 544 A1 disclosed. These measuring tubes can be used with flanges as well as without flanges in a pipeline. In this variant, a pipeline is interrupted and the measuring tube used. The measuring device is lighter overall and thus better transportable and manageable. A particular challenge with plastic measuring tubes is the expansion of the cross section of the plastic measuring tube under pressure. To prevent this, various constructive solutions can be chosen.

There are also known magnetic-inductive flow meters, which are configured annular and are inserted between flanges of a pipeline. These flowmeters are often referred to as wafer MID's or magnetic-inductive flow meters in wafer design. In the DE197 08 857 A1 a special variant of such a magnetic-inductive flowmeter is described, which is anchored between two flanges of a pipeline.

The particular advantage of this design is that unlike the most common electromagnetic flowmeters in this variant, no load-bearing measuring tube is needed, but the flowmeter is supported on the wall of the pipeline.

It is now an object of the present invention to provide a magnetic-inductive flow meter and / or an arrangement with a pipe and a magnetic-inductive flow meter, in which an additional solid pressure-stable measuring tube can be omitted and in which for mounting the flow meter no additional flanges at the pipe ends a pipeline are needed.

The present invention solves this object by a magnetic-inductive flowmeter with the features of claim 1 and by an arrangement with the features of claim 3.

A magnetic-inductive flowmeter according to the invention for detecting a flow and / or a flow velocity of a flowable medium comprises a base body which has a magnet system with at least two coil systems. Furthermore, the main body has at least two measuring electrodes for tapping a measuring signal.

The main body is designed as a ring with a medium-contacting ring inner surface. In this case, for example, the necessary components for flow measurement, such as coils, measuring electrodes, etc. may be arranged around or in a plastic ring or the like and then encapsulated by a potting compound to a base body comprising the aforementioned components.

The magnetic-inductive flowmeter has a locking element or a plurality of locking elements, which or which are connected to the base body and which are extendable from an outer contour of the base body.

These locking elements serve to support the pipe wall of a pipeline. Thus, the flowmeter can first be introduced into a pipeline and then anchored or clamped by extending the locking elements, also Abstützfüße, in cross-section of the pipeline.

Particularly advantageous, the magnetic-inductive flowmeter at least four Have locking elements, so that a uniform support against the pipe wall can be done.

Also according to the invention is an arrangement comprising a pipeline for guiding a flowable medium and a magnetic-inductive flowmeter for detecting a flow and / or a flow velocity of the flowable medium. The magnetic-inductive flowmeter comprises a base body which has a magnet system with at least two coil systems. Furthermore, the flowmeter has at least two measuring electrodes for tapping a measuring signal.

According to the invention, the main body is designed as a ring with a medium-contacting annular inner surface. As a ring in the context of the present invention is not necessarily a circular ring to understand but it can also be an oval ring or depending on the pipe shape, e.g. also be a square ring.

The main body of the magnetic-inductive flowmeter is inventively set on the inner circumference of a pipe wall of the pipeline. As a result, the pipe does not have to be interrupted but the ring can be inserted in one piece or in several parts in the pipeline and possibly assembled there and then set in the pipeline.

The present invention of piping and electromagnetic flowmeter assembly has particular advantages for installation in extra-large piping with nominal diameters greater than DN1000 and greater. Thus, e.g. in waterworks or in pumped storage plants man-high pipes available, which are water-bearing. Instead of capping the line and inserting a measuring device in such pipelines, an inner ring, which is configured as a magnetic-inductive flowmeter, can now be used or used.

The ring has a fixed internal volume and thus a fixed distance between the coils and the measuring electrodes. This distance remains constant during operation, since the ring is supported on the pipeline. As a result, a cross-sectional expansion of the ring, unlike flow meters with plastic measuring tubes, advantageously prevented. At the same time material is saved.

Especially with large nominal diameters of more than DN 1000, it will sometimes be necessary to make a single order for the corresponding nominal diameters. This is in the variant of an inner ring with subsequent encapsulation of the components of the flowmeter very easy and manufacturable with little design effort. Thus, now flow meters can be used in pipelines in which this technology was not used or only in very costly frame due to the high design cost.

In addition, wafer-MIDs have always required flanges for anchoring, and this can now be substituted for the ring variant by means of screws, bolts and other anchoring elements which are guided through the pipeline wall. However, only a hole seal but no surface seal along the flanges must be done. Depending on the pressure level, however, it may also be sufficient to support the ring on the inner wall of the pipeline. Both variants, e.g. a run through the pipe wall screw with the main body and a support variant of the body are implemented in an arrangement according to the invention.

Further advantageous embodiments of the magneto-inductive flowmeter and / or the arrangement according to the invention are the subject of the dependent claims.

Thus, it is advantageous if the magneto-inductive flowmeter of the arrangement according to the invention is a flowmeter according to the invention.

The coil systems and the measuring electrodes, and optionally other parts of the electromagnetic flowmeter such. Pole shoes, return plates and signal and / or power lines, in particular cables, can advantageously be embedded in a potting material of the base body. For this purpose, a food-compatible or FDA-compliant potting material is particularly preferred.

The main body may have an internal, in particular monolithic, ring which has at least one surface provided with the potting material. This inner ring may be a plastic ring or a metal ring with an electrically insulating plastic layer. The ring is of particular advantage since the respective components of a magnetic-inductive flowmeter can be arranged better around the inner ring during assembly. In addition, the locking elements of the flowmeter according to the invention can be fixed on the inner ring.

The arrangement may advantageously have at least one ring element, in particular two ring elements, for adapting the cross section of the pipeline to the cross section of the inner circumference of the main body of the flowmeter, wherein the ring element is arranged in the flow direction before and / or behind the flowmeter. The adaptation is preferably carried out by a monotone enlargement of the ring cross-section to the magnetic-inductive flowmeter out.

The flowmeter can be clamped in an advantageous embodiment of the invention by the locking elements against the pipeline, in particular via a press fit.

Optionally, a ring element for adapting the cross section of the pipeline to the cross section of the inner circumference of the main body of the flow meter have an adjustable diameter, in particular a diameter which can be adjusted to the cross section of the pipeline. This can e.g. a clamping ring with different locking positions or a ring which by pressing a locking means, e.g. a gland or a Verrastmittels, spans from a smaller to a larger diameter.

The ring element can also advantageously glued to the pipe wall, potted and / or screwed. It can also advantageously be provided on the edge side with a sealing joint.

It is also advantageous if the main body of the flowmeter and / or the ring elements by means of connecting elements, preferably of screws, bolts, projections and / or setscrews which protrude from the inner circumference of the pipe wall of the pipe and project into the lumen of the pipeline to the pipeline is or are fixed.

In a preferred embodiment, the flow meter may have a so-called EPD electrode for monitoring whether the inner cross section of the main body is completely filled with measuring medium or not.

For special applications, the base body can also have a level gauge. The level gauge may e.g. a capacitive level measuring device, which is arranged on the ring inner surface, so that the flow rate and flow rates in partially filled pipes, especially at a level of over 50% can be detected.

The invention will be explained in more detail with reference to an embodiment with the aid of the accompanying figure. It shows:

1 schematic view of an inventive arrangement and a flow meter in cross section; and

2 schematic view of an inventive arrangement and a flow meter in longitudinal section.

The structure and the measuring principle of a magnetic-inductive flowmeter is basically known. According to Faraday's law of induction, a voltage is induced in a conductor moving in a magnetic field. In the magnetic-inductive measuring principle, the fluid medium corresponds to the moving conductor. A magnetic field of constant intensity is generated by two field coils on either side of a measuring tube. Perpendicular to this are located on the tube inner wall of the measuring tube, two measuring electrodes, which tap the voltage generated when flowing through the medium. The induced voltage is proportional to the flow velocity and thus to the volume flow. The magnetic field built up by the field coils is generated by a clocked DC alternating polarity. This ensures a stable zero point and makes the measurement insensitive to influences by multiphase substances, inhomogeneities in the liquid or low conductivity. Magnetic-inductive flowmeters with coil arrangements with more than two field coils and other geometrical arrangements are known.

Usually there is a magnetic-inductive flow meter via a measuring tube which can be integrated into an existing pipe system.

1 shows in contrast schematically a magnetic-inductive flowmeter 1 in which no measuring tube is provided, which is inserted by means of flanges or flangeless between two ends of a pipeline. Rather, the flowmeter has a base body 15 which is formed as a ring and which in an existing and intact pipeline 2 can be used. In this case, the main body 15 a medium-contacting ring inside surface 16 on, so a surface which is in normal use or use of the flowmeter in contact with the measuring medium.

The pipeline 2 For example, it can be a concrete pipe to the water pipe. Such pipelines are used in large waterworks and / or in pumped storage plants with nominal sizes greater than DN 1000. However, all other known diameters and pipe materials are possible.

The annular body 15 includes a first coil system 3 and an opposite one second coil system 4 , which are diametrically opposed in the ring. In the present case, each of the two coil systems comprises 3 or 4 two coils for generating a magnetic field, which on a pole piece 5 or 6 are arranged. This pole piece is on a likewise the main body 15 assigned inner ring 9 , eg a plastic ring, put on. The coil systems 3 and 4 are through return plates 7 connected with each other. Furthermore, measuring electrodes 8th provided, which are diametrically opposed in the ring and which allow a signal tap of a measurement signal. This measurement signal is transmitted through a signal line, not shown, to a likewise in the ring 15 arranged transmitting and / or evaluation unit 12 transmitted.

This transmitting and / or evaluation unit 12 Either the measuring signal can be sent directly to a remote evaluation unit inside or outside the pipeline 2 or to convert the measurement data directly into a flow measurement value or a flow rate which is then sent to an output unit outside the pipeline 2 is transmitted. The transmission can be done wirelessly or by means of a cable. Furthermore, in the ring or remote from this ring, an energy source, such as a battery, may be provided by which the magnetic-inductive flowmeter is supplied with energy.

The components of the magnetic-inductive flowmeter are preferably in a potting material 14 embedded, which together with the inner ring 9 forms the body. The magnetic-inductive flowmeter 1 has locking elements 11 on, with which the electromagnetic flowmeter on a pipe wall of the pipeline 2 can support. These locking elements 11 are in 1 shown schematically as blocks. However, it is also possible and preferred that the locking elements are arcuate. In this case, the locking elements can also be configured substantially wider than this 1 is shown in order to achieve a high static friction with the pipe wall.

The locking elements 11 are opposite to an outer contour 17 of the basic body 15 of the magnetic-inductive flowmeter movable, preferably extendable, more preferably radially extendable. They are based on inventive use against an inner surface of the pipeline, whereby the magnetic-inductive flowmeter 1 in the lumen of the pipeline 2 is jammed. The inner radius of the ring 15 the electromagnetic flowmeter remains constant.

In this Verklemmposition the locking elements 11 For example, be locked so that the locking elements are fixed in a locked position. The extendability of the locking elements 11 can be limited by locking means, screws or the like.

For better insertion of the magnetic-inductive flowmeter into the pipeline, the measuring device can also consist of several ring segments, which are assembled and welded or otherwise connected, eg screwed, at the place of measurement, for example. Accordingly, in 1 two welds 13 shown.

Due to the compact design of the magnetic-inductive flowmeter, it is possible to offer a solution for pipelines for very large nominal widths.

2 schematically shows the magnetic inductive flowmeter in its installed position in the pipeline 2 , The pipeline 2 is typically traversed by a flowable medium M. In order not to generate flow congestion and turbulence, flow-guiding ring elements can be provided in the pipeline 10 before and / or behind the magnetic-inductive flowmeter 1 be arranged.

The flow-guiding ring elements 10 preferably allow a monotonous or gradual reduction in cross-section in the pipeline 2 in particular until reaching the inside diameter of the flowmeter. They may be formed, for example, a half-shell, wherein the half-shells are connected by screws or other fastening means and spaced from each other, so that the half-shells are pressed with appropriate spacing against the pipe inner wall. Consequently, the diameter of the flow-guiding ring elements during installation in the pipeline 2 be widened mechanically. The ring elements 10 can also be advantageously connected to each other via webs.

As an alternative to the aforementioned Verspannvarianten against the pipe wall, both the main body of the flow meter and the ring elements by means of connecting elements, e.g. Screws, bolts, protrusions or setscrews, which protrude from the inner circumference of the pipe wall and project into the lumen of the pipe, are set.

LIST OF REFERENCE NUMBERS

1

 Flowmeter

2

 pipeline

3, 4

 coil system

5, 6

 pole

7

 Feedback sheet

8th

 measuring electrodes

9

 ring

10

 flow-guiding ring element

11

 Fixing element

12

 Transmitting and / or evaluation unit

13

 Weld

14

 grout

15

 annular body

16

 Ring inner surface

17

 outer contour

M

 Flow direction of the medium

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102013102544 A1 [0005]
• DE 19708857 A1 [0006]

Claims (11)

Magnetic-inductive flowmeter ( 1 ) for detecting a flow rate and / or a flow rate of a flowable medium, comprising a base body which has a magnet system with at least two coil systems ( 3 . 4 ), and at least two measuring electrodes ( 8th ) for tapping a measuring signal, characterized in that the main body ( 15 ) as a ring with a medium-contacting ring inner surface ( 16 ), and in that the magnetic inductive flow meter ( 1 ) one locking element or several locking elements ( 11 ), which or which with the main body ( 15 ) and which of an outer contour ( 17 ) of the basic body ( 15 ) are extendable. Magnetic-inductive flowmeter according to one of the preceding claims, characterized in that the magnetic-inductive flowmeter ( 1 ) at least four locking elements ( 11 ) having. Arrangement comprising a pipeline ( 2 ) for guiding a flowable medium and a magnetic-inductive flowmeter ( 1 ) for detecting a flow rate and / or a flow rate of the flowable medium, comprising a main body which has a magnet system with at least two coil systems ( 3 . 4 ), and at least two measuring electrodes ( 8th ) for tapping a measuring signal, characterized in that the main body ( 15 ) as a ring with a medium-contacting ring inner surface ( 16 ) is formed, and that the basic body ( 15 ) of the electromagnetic flowmeter ( 1 ) on the inner circumference of a pipe wall of the pipeline ( 2 ). Arrangement according to claim 3, characterized in that the magneto-inductive flowmeter is a flowmeter according to claim 1. Magnetic-inductive flowmeter according to claim 1 or 2 and / or arrangement according to claim 3, characterized in that the coil systems ( 3 . 4 ) and the measuring electrodes ( 8th ) in a potting material ( 14 ) of the basic body ( 15 ) are embedded. Magnetic-inductive flowmeter according to one of the preceding claims and / or arrangement according to one of the preceding claims, characterized in that the flowmeter additionally comprises one or more return plates and / or pole shoes, which in the potting material ( 14 ) of the main body are embedded. Magnetic-inductive flowmeter according to one of the preceding claims and / or arrangement according to one of the preceding claims, characterized in that the main body ( 15 ) an inner ring ( 9 ), which at least one with the potting material ( 14 ) has provided surface. Arrangement according to one of the preceding claims, characterized in that the arrangement comprises at least one ring element ( 10 ), in particular two ring elements ( 10 ), for adapting the cross section of the pipeline to the cross section of the inner circumference of the body ( 15 ) of the flowmeter ( 1 ), wherein the ring element ( 10 ) in the flow direction (M) before and / or behind the flow meter ( 1 ) is arranged. Arrangement according to one of the preceding claims, characterized in that the flowmeter by the locking elements ( 11 ) against the pipeline, in particular via a press fit, is braced. Arrangement according to one of the preceding claims, characterized in that the ring element ( 10 ) for adapting the cross section of the pipeline to the cross section of the inner circumference of the body ( 15 ) of the flowmeter has an adjustable diameter, in particular a diameter which can be adjusted to the cross section of the pipeline. Arrangement according to one of the preceding claims, characterized in that the basic body ( 15 ) of the flowmeter ( 1 ) and / or the ring elements ( 10 ) by means of connecting elements, preferably screws, bolts, projections and / or set screws, which from the inner circumference of the pipe wall of the pipeline ( 2 ) and into the lumen of the pipeline ( 2 ), at the pipeline ( 2 ).

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