DE102006036907A1 - Flow meter manufacturing method for process automation, involves attaching measuring unit and controlling/evaluating unit at measuring pipe for determining volume flow and/or process connection for positioning measuring pipe in pipeline - Google Patents

Abstract

The method involves attaching a pipe material of defined length at a calibration system, and calibrating the pipe material with different, defined volume flows. The pipe material is divided into two partial pieces, which have a length defined for a measuring pipe of the meter. A measuring unit and a controlling/evaluating unit are attached at the measuring pipe for determining the volume flow and/or a process connection for positioning the measuring pipe in a pipeline. Calibrated data is stored in the controlling/evaluating unit, which is attached to the measuring pipe. An independent claim is also included for a flow meter with a measuring unit.

Description

The The invention relates to a method of manufacturing flowmeters that in process automation for determining the volume flow of a flowing through a pipeline Medium used. In particular, the invention relates to a method for group calibration of flowmeters. Farther The invention relates to a flowmeter for determination and / or monitoring the volume flow of a medium through a pipeline and on a Measuring tube for a corresponding flow meter.

For the purpose of Calibration of a flowmeter will be the fully assembled meter, consisting of measuring tube, measuring unit and control / evaluation unit, installed in a suitable calibration system. Then be set at least two different volume flows in the calibration, and the meter is applied against a high accuracy master, e.g. a Coriolis flowmeter, calibrated. The calibration data are stored in the control / evaluation unit assigned to the measuring device stored so that they during the subsequent measurement operation of the flowmeter are available. After this individual calibration of the flowmeter is the meter removed from the calibration, and the next pre-assembled meter is in The calibration system is installed and calibrated. It goes without saying even that, due to the individual calibration of the flowmeters the installation and removal times and the respective adjustment of the flow rates relative time consuming and therefore expensive.

Of the Invention is based on the object, in terms of time and Cost proposed optimized method for the production of flowmeters. Furthermore, the invention has the object, a cost to manufacturing flowmeter or a cost to be manufactured measuring tube for a flow meter provide.

The Task is relative solved by the method, that one for Measuring tubes of flowmeters suitable pipe material of a defined length to a calibration is connected, that at the tube material at least one measuring unit and a control / evaluation unit for determining the volume flow attached or provided that the pipe material with measuring unit calibrated at least two different, defined volume flows is that the pipe material is divided into sections, each one for a Measuring tube of a flow meter defined Have length, that at each measuring tube a measuring unit and a control / evaluation unit for Determination of the volume flow and / or a process connection for positioning the measuring tube is mounted in the pipeline and that the calibration data in the control / evaluation unit, which is assigned to each measuring tube, be deposited. Of course can the calibration unit and the control / evaluation unit Already assigned to the pipe material before the pipe material is connected to the calibration system.

before has already been described that it is in the hitherto used Calibration procedure is a single calibration: Each individual flowmeter is separated calibrated, i. it must be in the calibration facility for calibration installed and then be expanded again. On the other hand, the inventive method allows For the first time a simultaneous group calibration of a large number of 'half-finished' flowmeters. These novel variant of the calibration is made possible by that as a piece goods or as semi-finished existing pipe material in the calibration system is installed and calibrated. That for the inventive method used pipe material has identical dimensions in known tolerances, so that over a group calibration of Sold by the meter or semifinished product for all the pipe material obtained parts, from which below the measuring tubes for the flowmeters be manufactured, can be used. In a rough estimate can be say that saving time for the Calibration process is proportional to the number of flowmeters the above the group calibration calibrated according to the invention become.

According to one advantageous embodiment of the method according to the invention is provided that one flange in each end area of the individual measuring tubes is attached. The design is thus about a flow meter with fixed flanges.

alternative It is suggested that in each end region of the individual measuring tubes a folded or beaded one tail or a folded or beaded tail is attached with a loose flange. In these embodiments it is either a flow meter with loose flanges or a wafer over a suitable attachment mechanism between two on the pipeline fixed flanges is clamped.

As a particularly advantageous and cost-effective development of the method according to the invention, it is considered when flanged to a predominantly made of plastic measuring tube on both sides be welded from a thermoplastic material by means of a thermosplastic bonding method. The thermoplastic joining method is preferably an ultrasonic welding.

at the flowmeters, the over the inventive group calibration process are produced, it is, for example, magnetic-inductive or ultrasonic flowmeters. A magnetic-inductive Flowmeter consists of a measuring tube, which moves from the medium towards the measuring tube axis flows through becomes, from a magnet system, which passes through the measuring tube, generated magnetic field extending substantially transversely to the measuring tube axis, and at least one measuring electrode coupled to the medium, in a lying substantially perpendicular to the magnetic field Area of the measuring tube is arranged. Furthermore, a control / evaluation unit provided on the basis of the induced in the at least one measuring electrode measuring voltage information about provides the volume or mass flow of the medium in the measuring tube.

A preferred, cost-effective Design of the magnetic-inductive flowmeter according to the invention sees before that, for the case that the measuring tube predominantly is made of plastic, as measuring electrode a measuring electrode from an electrically conductive thermoplastic or from a filled with conductive particles thermoplastics is used; this measuring electrode is preferably via a thermoplastic bonding method, e.g. an ultrasonic welding, in a corresponding opening in the wall of the measuring tube inserted. Possible is it about it In addition, the tube material at the position of the at least one measuring electrode electrically conductive embody. This is mainly from Plastic existing pipe material provided at the for the measuring electrode Position or to the for the measuring electrodes provided positions with a suitable conductive Doping provided.

• – es entfällt das Anbringen der Bohrungen in der Wandung des Messrohrs bzw. des Rohrmaterials;
• – es gibt keine Dichtungsprobleme, die ansonsten beim Einbau von separaten Messelektroden in die Bohrungen auftreten können;
• – es kann auf eine Vielzahl von Befestigungsteilen verzichtet werden, wie beispielsweise auf eine Schnapphülse oder auf ein Federpaket, das im Stand der Technik zur Befestigung einer Messelektrode in einer Bohrung der Wandung des Messrohrs unerlässlich ist.

In principle, the doping in all areas of the measuring tubes, in which the tube material is subdivided below, already be provided during the manufacture of the tube material. These are, so to speak, 'intrinsic' measuring electrodes of the tube material. The great advantage of the partial doping of measuring tubes or of tube material with conductive particles in the region of the measuring electrodes has the advantage that it is entirely possible to omit several otherwise necessary steps in the production method of a magnetic-inductive flowmeter:

• - It eliminates the attachment of the holes in the wall of the measuring tube or the pipe material;
• - There are no sealing problems that can otherwise occur when installing separate measuring electrodes in the holes;
• - It can be dispensed with a variety of fasteners, such as a snap-on sleeve or a spring assembly, which is essential in the prior art for attaching a measuring electrode in a bore of the wall of the measuring tube.

in the Trap of an ultrasonic flowmeter, the measuring unit sits down from at least two ultrasonic sensors together, in the flow direction of the medium offset in opposite Regions of the measuring tube are arranged and the alternating ultrasonic measuring signals send and / or receive. The control / evaluation unit determines the volume flow of the medium through the pipe preferably after the transit time difference method or the correlation method. Flowmeters that operate according to the transit time difference method, are under the applicant offered and sold the name PROSONIC FLOW.

According to one advantageous development of the invention magnetic or inductive Ultrasonic flowmeter it is the pipe material to a semi-finished, which consists of at least two different material layers is constructed. Especially is the material layer coming into contact with the medium, that is the liner, made of an electrically insulating and / or a corrosion resistant Material made.

• – einer äußeren Materiallage aus einem abriebsfesten Kunststoff,
• – einer mittleren Materiallage aus einer Metallfolie, die diffusionsdicht ist, und
• – einer inneren, mit dem Medium in Kontakt kommenden Materiallage, die aus einem für Trinkwasseranwendungen zugelassenen Material besteht.

According to a preferred embodiment of the flowmeter according to the invention, it is proposed that the tube material is moreover resistant to diffusion and is composed of the following three material layers:

• An outer material layer of an abrasion-resistant plastic,
• A middle material layer of a metal foil which is diffusion-tight, and
• - an internal material layer coming into contact with the medium, consisting of material approved for drinking water applications.

The same Incidentally, tube material is about the Company egeplast available.

In particular, the outer layer of material serving as the protective or sheath layer is mineral-reinforced polypropylene. The middle material layer acting as a diffusion layer inwards and outwards preferably consists of a multilayer aluminum foil, while the inner material layer forming the core tube preferably consists of a polyethylene suitable for drinking water. In this particular embodiment, the invention suitable flow meter also in the field of drinking water supply can be used easily.

• – einer Mantelschicht aus einem abriebsfesten Kunststoff,
• – einer mittleren Sperrschicht, die aus einem diffusionsdichten Material gefertigt ist, und
• – einer inneren, mit dem Medium in Kontakt kommenden Kernschicht, die aus einem für Trinkwasser zugelassenen Material besteht.

The problem is solved with regard to the measuring tube for an electromagnetic flowmeter or for an ultrasonic flowmeter in that the measuring tube consists of a diffusion-tight tube material with three layers:

• A cladding layer of an abrasion-resistant plastic,
• A middle barrier layer made of a diffusion-proof material, and
• - An inner, coming into contact with the medium core layer, which consists of a permitted for drinking water material.

Prefers is the protective or sheath layer of mineral-reinforced polypropylene manufactured. The diffusion-tight barrier layer is preferably a multilayer aluminum foil, and the inner, the core tube forming material layer is preferably made made of drinking water suitable polyethylene.

The The invention will be explained in more detail with reference to the following figures. It shows:

1 a flow chart illustrating the flow of the method according to the invention.

2 a schematic representation of a built-in a calibration pipe material with which a group calibration is performed and

2a : a cross section through the pipe material according to the marking AA 2 ,

1 shows a flowchart illustrating the flow of the method according to the invention. Under point 1 the procedure is started. According to point 2 becomes a piece goods or a semi-finished product of a pipe material 5 the length L in the calibration 1 built-in. Under point 3 become the measurement unit 2 and the control / evaluation unit 9 to the pipe material 5 assembled. The measuring unit 2 For example, is designed and mounted so that it allows to determine the flow rate on the magnetic-inductive principle. It is considered particularly advantageous in this context if the pipe material 5 mainly consists of plastic and it is the measuring electrode 4 is an electrically conductive plastic electrode. This can be via a thermoplastic bonding process, if necessary, on-site in an opening in the wall of the pipe material 5 assemble.

As mentioned in the previous section, it may be in the unit of measurement 2 also act to ultrasonic sensors that the volume flow of the medium 6 through the pipeline 7 Determine according to the transit time difference principle. The transit time difference principle takes advantage of the effect that ultrasonic measuring signals, which are in the flow direction S of the medium 6 spread, for the passage of the identical route a shorter time than ultrasonic measurement signals that propagate opposite to the flow direction S. It goes without saying that the process step under point 3 also before the process step under point 2 can be done.

Under point 4 becomes the pipe material 5 with the integrated measuring unit 2 with two different, defined volume flows against a master flowmeter 14 calibrated. The obtained calibration data are stored.

Under point 5 becomes the pipe material 5 divided into sections of length l, wherein the length l corresponds to the length of a measuring tube of a flowmeter. Has the pipe material 5 a length L, so can be from the tube material 5 manufacture several measuring tubes of length l. Under point 6 At each measuring tube, a measuring unit is created 2 and control / evaluation unit 9 for determining the volume flow and / or a process connection 13 for positioning the measuring tube in the pipeline 7 appropriate. Under point 7 become the under the point 4 obtained calibration data of the control / evaluation unit 9 provided by each individual measuring tube. At point 8th is the process of the invention for the production of flow meters finished.

In 2 is a schematic representation of a in a calibration 1 built-in pipe material 5 shown, with which the group calibration according to the invention described above is performed.

2a shows a cross section through the pipe material 5 according to the marking AA 2 , In a preferred embodiment of the flowmeter according to the invention or the measuring tube for a flow meter is the tube material 5 three-layer, diffusion-resistant and suitable for drinking water applications.

• – eine äußere Materiallage 12 aus einem abriebsfesten Kunststoff,
• – eine mittlere Materiallage 11 aus einer Metallfolie, die diffusionsdicht ist, und
• – eine innere, mit dem Medium 6 in Kontakt kommenden Materiallage 10, die aus einem für Trinkwasseranwendungen zugelassenen Material besteht.

Suitable material layers 10 . 11 . 12 are:

• - an outer material layer 12 made of an abrasion-resistant plastic,
• - a middle material layer 11 from a metal foil which is diffusion-tight, and
• - an inner, with the medium 6 in contact coming material situation 10 , which consists of a material approved for drinking water applications.

In particular, it is the outer, serving as a protective or cladding layer Mate riallage 12 mineral-reinforced polypropylene. The middle material layer, which acts as a diffusion layer inside and outside 11 preferably consists of a multilayer aluminum foil, while the inner, the core tube forming material layer 10 preferably consists of a drinking water suitable polyethylene.

It goes without saying that a different structure or other materials, such as suitable metals, as a pipe material 5 can be used for the group calibration according to the invention.

To previous point was mentioned that in each case a process connection 13 is provided in the two end regions of each measuring tube. The attachment of the process connection 13 takes place after the subdivision of the pipe material 5 in sections corresponding to the measuring tubes. A process connection is preferably a crimped component which is welded to a smooth end region of a measuring tube.

1

calibration

2

measuring unit

3

electromagnet

4

measuring electrode

5

tubing

6

medium

7

pipeline

8th

Reservoir / tank

9

Control / evaluation unit

10

inner material layer

11

middle material layer

12

outer material layer

13

process connection

14

Master flowmeter

Claims (14)

Method of manufacturing flowmeters used in process automation for determining the volume flow of a through a pipeline ( 7 ) flowing medium ( 6 ), characterized in that a pipe material suitable for flowmeters ( 5 ) of a defined length (L) to a calibration system ( 1 ) is connected to the pipe material ( 5 ) at least one measuring unit ( 2 ) and a control / evaluation unit ( 9 ) are provided or provided for determining the volume flow that the pipe material ( 5 ) is calibrated at at least two different, defined volume flows that the pipe material ( 5 ) is subdivided into sections, each having a length (l) defined for a measuring tube of a flow meter, that at each measuring tube a measuring unit ( 2 ) and control / evaluation unit ( 9 ) for determining the volume flow and / or a process connection ( 13 ) for positioning the measuring tube in the pipeline ( 7 ) and that the calibration data in the control / evaluation unit ( 9 ), which is assigned to each measuring tube, are deposited. A method according to claim 1, characterized in that in each end region of the individual measuring tubes in each case a flange ( 13 ) is attached. A method according to claim 1, characterized in that in each end region of the individual measuring tubes a bent end piece or crimped or a bent or crimped end piece with a loose flange ( 13 ) is attached. A method according to claim 3 or 4, characterized in that the measuring tube is made predominantly of plastic and that the respective consisting of a thermoplastic material process connection ( 13 ) is welded by a thermosplastic method to the end portions of the measuring tube. Flowmeter manufactured according to at least one of claims 1-4, characterized in that the measuring unit ( 2 ) around a magnet system ( 3 ) and at least one measuring electrode ( 4 ) and that the control / evaluation unit ( 9 ) the volume flow of the medium ( 6 ) through the pipeline ( 7 ) determined according to the principle of electromagnetic induction. Flowmeter according to claim 5 or 6, characterized in that the measuring tube is made predominantly of plastic and that the at least one measuring electrode ( 4 ) consists of an electrically conductive thermoplastic material or of a thermoplastic filled with conductive particles, wherein the measuring electrode ( 4 ) is connected to the measuring tube via a thermoplastic bonding method. Flowmeter according to claim 6, characterized in that the measuring tube is made predominantly of plastic and that it is in the measuring electrode ( 4 ) around an intrinsic measuring electrode ( 4 ) by suitable conductive doping of the plastic of the pipe material ( 5 ) or a measuring tube is created. Flowmeter, which is produced according to at least one of claims 1-4, characterized in that the measuring unit is at least two ultrasonic sensors which transmit and / or receive ultrasonic measuring signals, and in that the control / evaluation unit ( 9 ) determines the volume flow of the medium through the pipeline according to the transit time difference method or according to the correlation method. Flowmeter according to claim 7 or 8, characterized in that it is in the pipe material ( 5 ) is a semi-finished product which consists of at least two different material layers ( 10 . 11 . 12 ) is constructed. Flowmeter according to claim 7 or 9, characterized in that it is at the with the medium ( 6 ) coming into contact material situation ( 10 ) is a liner made of an electrically insulating and / or a corrosion resistant material. Flowmeter according to claim 9 or 10, characterized in that the pipe material ( 5 ) is diffusion-resistant and composed of three material layers: an outer material layer ( 12 ) of an abrasion-resistant plastic, - a middle material layer ( 11 ) of a metal foil, which is diffusion-tight, and - an inner, with the medium ( 6 ) coming into contact material situation ( 10 ), which consists of a material approved for drinking water applications. Flowmeter according to claim 11, characterized in that it is at the outer, serving as a protective or cladding layer material layer ( 12 ) is mineral-reinforced polypropylene, that it is in the middle, acting as a diffusion layer material layer ( 11 ) is a multi-layer aluminum foil and that it is in the inner, the core tube forming material layer ( 10 ) is drinking water suitable polyethylene. Measuring tube for a magnetic-inductive flowmeter or for an ultrasonic flowmeter, characterized in that the measuring tube of a diffusion-tight tube material ( 5 ) with three material layers ( 10 . 11 . 12 ) consists of: - a cladding layer ( 12 ) of an abrasion-resistant plastic, - a middle barrier layer ( 11 ), which is made of a diffusion-proof material, and - an inner, with the medium ( 6 ) contacting core layer ( 10 ), which consists of a material approved for drinking water. Measuring tube according to claim 13, characterized in that the protective or jacket layer ( 12 ) consists of mineral-reinforced polypropylene, that it is in the diffusion-tight barrier layer ( 11 ) is a multilayered aluminum foil and that the inner core layer forming the core tube ( 10 ) is made of drinking water suitable polyethylene.