GB2310287A - Measuring tube assemblies and methods of making the same for electromagnetic flowmeters - Google Patents
Measuring tube assemblies and methods of making the same for electromagnetic flowmeters Download PDFInfo
- Publication number
- GB2310287A GB2310287A GB9603298A GB9603298A GB2310287A GB 2310287 A GB2310287 A GB 2310287A GB 9603298 A GB9603298 A GB 9603298A GB 9603298 A GB9603298 A GB 9603298A GB 2310287 A GB2310287 A GB 2310287A
- Authority
- GB
- United Kingdom
- Prior art keywords
- tube
- substance
- assembly
- aluminium
- electrodes
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- 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
- G01F1/56—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 electric or magnetic effects
- G01F1/58—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 electric or magnetic effects by electromagnetic flowmeters
- G01F1/584—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 electric or magnetic effects by electromagnetic flowmeters constructions of electrodes, accessories therefor
-
- 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
- G01F1/56—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 electric or magnetic effects
- G01F1/58—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 electric or magnetic effects by electromagnetic flowmeters
-
- 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
- G01F1/56—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 electric or magnetic effects
- G01F1/58—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 electric or magnetic effects by electromagnetic flowmeters
- G01F1/586—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 electric or magnetic effects by electromagnetic flowmeters constructions of coils, magnetic circuits, accessories therefor
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Fluid Mechanics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Measuring Volume Flow (AREA)
Description
23102187 Measuring tube assemblies and methods of making the same for
elgctromagnetic flowmeters This invention relates to measuring tube assemblies for electromagnetic flowmeters and to methods of making such assemblies.
Known tube assemblies for electromagnetic flowmeters comprise a metallic measuring tube made from a non-magnetic material, a set of magnetic coils for generating a magnetic field in a direction substantially at right angles to the direction of flow through the tube, and electrodes arranged in bores substantially at right angles to the direction of the magnetic field and substantially at right angles to the direction of flow.
The use of a metallic tube makes it necessary to isolate the electrodes and fluid from the inner side of the measu,7ing tube in order not to short-circuit the induced signal voltage.
US patent specification 5,062,305 relates to a method of making a measuring tube for an electromagnetic flowmeter comprising a tubular body of non-magnetic material, such as stainless steel, metal electrodes arranged in respective through-passages, and a continuous lining formed from a meltable electrically non-conductive material covering the inner circumferent'ial surfaces of the tubular body and the through-passages.
In the above-mentioned prior art patent, the inside of the measuring tube is coated with an isolating layer consisting of an enamel which extends into the annular space between the electrodes and the non-magnetic metallic tube.
Other types of liners are, however, known in which different types of plastic materials, synthetic plastic materials and resins are used, the liner, at the outer ends of the metering tube, being flared out for the purpose of holding the liner in position (see, for example, US patent 4,388,834). In such flowmeter tubes, secure fixing of, and connection to, the electrodes can be a problem and involve somewhat complicated arrangements. RTN Isolating liners made of Teflonor Neoprene are used but they are relatively expensive.
The ends of such flowmeter tubes often terminate in flanges by which the flowmeter tube can be mounted in pipework carrying the fluid, the flow of which is to be measured. The magnetic coils are generally covered by a metal housing around the middle portion of the flowmeter tube. The housing, the portion of the tube between the housing, and the flanges are usually painted to give the exterior of the flowmeter tube a uniform attractive finish acceptable to customers.
The known techniques of preparing, insulating ahd finishing tubes for flowmeters are relatively cosc'-'1,y and it is an object of the invention to provide a flowmeter - 3 tube that can be made more cheaply.
The present invention provides a measuring tube assembly for an electromagnetic flowmeter, the assembly comprising a tube of non-magnetic metal material, magnetic coils for producing a magnetic field across the direction in which a fluid flows, in use, though the tube, electrodes arranged within the tube, cross-wise with respect to the magnetic field, to contact said fluid flowing, in use, through the tube, an electricallyinsulating layer provided at the interior of the tube to insulate the electrodes from the tube body, and a corrosion-resistant layer on at least a part of the exterior of the tube characterized in that the said layers are constituted by the same substance. Such a construction is relatively cheap to make because inexpensive corrodible and easy to work materials can be used in the metal part of the tube assembly and because it is particularly economical to use the same substance both for insulating the electrodes from the interior of the tube and protecting against corrosion. It is no longer necessary to carry out internal lining and external finishing, such as painting, as two separate processes and effective isolation can be achieved in a cheap and easy operation. By these means the overall price of the tube assembly can be reduced and, indeed, the surprising cost saving of up to 50% can be achieved by the use of the invention.
Preferably, the substance lines bores in the tube through which connections to the electrodes pass. By this means separate insulating bushings for the connections to the electrodes may be omitted.
Preferably, a respective pipe coupling means, for example, a flange or a threaded coupling, is provided at each end of the tube, and the substance covers the exterior of the pipe coupling means. Such a construction enables a cheap and easily worked yet corrodible material, for example, mild steel liable to rusting, to be used in the tube assembly.
Advantageously, the whole of the tube, both internally and externally, is covered with the substance. The trouble of applying the substance selectively is then avoided and a uniform insulating and corrosionresisting finish both inside and out is achieved. When the tube is protected on all surfaces against corrosion, final painting of the outer surfaces, or an outer casing become unnecessary and an isolation layer can be achieved not only inside the tube but also around the surfaces on which the electrodes are to be mounted.
The body of the tube may be made of stainless steel and the pipe coupling means may be made of steel liable to rust welded to the stainless steel body.
In another form of construction, the tube is made of aluminium. A tube of aluminium is rigid and strong enough to carry the weight of the magnetic system but does not add substantially to the overall weight of the assembly.
Advantageously, the substance is a polymer material, in particular, a polyamide thermoplastics material, for example, nylon, applied as a powder coating.
The substance may be an epoxy resin applied as a powder coating or by some other technique, for example, painting.
When an aluminium tube is used, the substance advantageously comprises an oxide layer, for example, produced by anodizing, or a nitride layer on the aluminium.
Advantageously, the magnetic coils are located within a housing of plastics material. By this means, an inexpensive, lightweight and attractive housing for the coils can readily be provided and a smooth, attractive looking external appearance achieved.
The present invention also provides a method of making a measuring tube assembly for an electromagnetic flowmeter comprising:
taking a tube of non-magnetic metal material, providing the same substance, having both electrically-insulating and corrosion-resisting properties, at both the interior and the exterior of the tube, to form a layer at the interior of the tube to insulate the electrodes from the tube body, and a layer on at least a part of the exterior of the tube to resist - 6 corrosion, and mounting magnetic coils on the tube for producing a magnetic field across the direction in which a fluid flows, in use, though the tube, and arranging electrodes within the tube, cross-wise with respect to the magnetic field, to contact said fluid flowing, in use, through the tube.
Advantageously, the substance is applied by immersion of the tube in the said substance, in particular, the tube may be immersed in a fluidised bed of the substance.
Another way of applying the substance is by spraying.
Yet another way of applying the substance is by chemical treatment, for example, to produce an oxide or a nitride layer on an aluminium tube.
Measuring tube assemblies in a-cordance with the invention and methods of making the same will now be described, by way of example only, with reference to the accompanying drawings, in which:
Fig. 1 is a diagrammatic cross-section through a measuring tube assembly; Figure 2 is an end view of the measuring tube assembly; and Figure 3 is a diagrammatic cross-section through a part of the measuring tube assembly.
Referring to the accompanying drawings, a measuring tube assembly 1 for an electromagnetic flowmeter comprises a tube 2 of stainless steel of circular cross section. Two magnetic coils, shown diagrammatically as 3, are arranged diametrically opposite one another within an annular housing 4 of plastics material on the outside of the tube 2. The coils 3 are for producing a magnetic field at right angles to the direction 5 in which fluid flows though the tube 2. Two electrodes 6 (omitted from Figure 1 for clarity) are arranged diametrically opposite one another within the tube 2 on an axis at right angles to the magnetic field generated by the coils 3 and to the flow direction 5. The electrodes 6 contact fluid flowing through the tube 2 and an electrically-insulating layer 7 is provided at the interior of the tube to insulate the electrodes from the tube. On the outside of the tube 2, a corrosion-resistant layer 8 is provided. The layers 7 and 8 are constituted by the same substance. The tube 2 includes bores 9 through which connections 1.0 to the electrodes 6 pass and the said substance is provided in the bores as can be seen in Figure 3.
Respective mild steel flanges 11 and 12, welded to the tube 2, are provided at each end of the tube 2 and the insulating and corrosionresisting substance is provided over the flanges as can be seen in Figure 1. The flanges 11 and 12 are provided with eight holes 13 (Figure 2) through which respective bolts can be passed to secure the tube assembly in adjoining pipework.
The plastics material housing 4 includes a terminal box 14 which provides the means of connecting the coils 3 to external circuitry of the flowmeter.
As can be seen from the drawings, the whole of the tube 2, both internally and externally, is covered with the said substance. As the flanges 11 and 12 are of corrodible steel the said substance prevents them from rusting.
The said substance is a polymer material applied as a powder coating. The coating materials sold under the name RilsanXby Elf Atochem of Paris are particularly suitable and comprise a group of synthetic thermoplastics of the polyamide type applicable by fluidised bed dipping, electrostatic spraying or flame spraying.
In an alternative construction, the tube is made of aluminium and may be either flangeless or provided with integral flanges and the layers 7 and 8 are constituted by an oxide layer, for example, produced by anodizing, or a nitride layer on the aluminium. Instead, a powder coating could be applied to the aluminium.
The electrodes 6 are securely fitted in the bores 9 by screw mounting, force fitting or in any other suitable manner so that fluid of which the flow is to be measured does not leak from the tube.
The measuring tube assembly 1 is made by taking the tube 2 of nonmagnetic metal material, providing the same substance, having both electrically-insulating and corrosion-resisting properties, at both the interior and the exterior of the tube, to form the layers 7 and 8, and mounting the magnetic coils 3, and fixing the electrodes 9.
Modifications to the embodiments of the invention described with reference to the drawings are possible.
If desired, a supplementary insulating bushing may be provided about each connection 10 or such a bushing may be used instead of providing the said substance in the bores 9.
The plastics material housing may instead be made of metal, for example, aluminium.
If desired, the outside of the tube can be selectively coated with the said substance and a housing for the electrodes or the electromagnetic system welded to the tube where it is uncoated, thereby saving on coating r,--.terial.
If desired, mounting means for the electromagnetic system may be welded to the tube before coating.
By means of the coating an attractive looking surface can be achieved so that the need for an outer casing may be avoided.
- 10
Claims (26)
1. A measuring tube assembly for an electromagnetic flowmeter, the assembly comprising a tube of non-magnetic metal material, magnetic coils for producing a magnetic field across the direction in which a fluid flows, in use, though the tube, electrodes arranged within the tube, cross-wise with respect to the magnetic field, to contact said fluid flowing, in use, through the tube, an electrically-insulating layer provided at the interior of the tube to insulate the electrodes from the tube body, and a corrosion-resistant layer on at least a part of the exterior of the tube characterized in that the said layers are constituted by the same substance.
2. An assembly as claimed in claim 1, wherein the substance lines bores in the tube through which connections to the electrodes pass.
3. An assembly as claimed in claim 1 or claim 2, wherein a respective pipe coupling means is provided at each end of the tube, and the substance covers the exterior of the pipe coupling means.
4. An assembly as claimed in claim 3, wherein the pipe coupling means comprise a respective flange at each end of the tube.
5. An assembly as claimed in any preceding claim, wherein the whole of the tube, both internally and externally, is covered with the substance.
6. An assembly as claimed in claim 3, claim 4, or claim 5 when dependent on claim 3, wherein the pipe coupling means are of a steel liable to rust and the substance provides protection against rusting.
7. An assembly as claimed in claim 6, wherein the body of the tube is made of stainless steel and the pipe coupling means are made of steel liable to rust welded to the stainless steel body.
8. An assembly as claimed in any of claims 1 to 5, wherein the tube is made of aluminium.
9. An assembly as claimed in any preceding claim, wherein the substance is a polymer material applied as a powder coating.
10. An assembly as claimed in claim 9, wherein the substance is a polyamide thermoplastics material.
11. An assembly as claimed in any of claims 1 to 9, wherein the substance is an epoxy resin.
12. An assembly as claimed on claim 8, wherein the substance comprises an oxide layer on the aluminium.
13. An assembly as claimed in claim 8, wherein the substance comprises a nitride layer on the aluminium.
14. A tube as claimed in any preceding claim, wherein the magnetic coils are located within a housing of plastics material.
15. A measuring tube assembly for an electromagnetic flowmeter, the assembly being substantially as herein described with reference to, and as illustrated by, the accompanying drawings.
16. A method of making a measuring tube assembly for an electromagnetic flowmeter comprising:
taking a tube of non-magnetic metal material, providing the same substance, having both electrically-insulating and corrosion-resisting properties, at both the interior and the exterior of the tube, to form a layer at the interior of the tube to insulate the electrodes from the tube body, and a layer on at least a part of the exterior of the tube to resist corrosion, and mounting magnetic coils on the tube for producing a magnetic field across the direction in which a fluid flows, in use, though the tube, and arranging electrodes within the tube, cross-wise with respect to the magnetic field, to contact said fluid flowing, in use, through the tube.
17. A method as claimed in 15, wherein the substance is applied by immersion of the tube in the substance.
18. A method as claimed in claim 17, wherein the tube is immersed in a fluidised bed of the substance.
19. A method as claimed in claim 15, wherein the substance is applied by spraying.
20. A method as claimed in any one of claims 17 to 19f wherein the substance is a powder coating polyner.
21. A method as claimed in claim 15, wherein the substance is applied by a chemical reaction with the material of the tube.
22. A method as claimed in claim 21, wherein the tube is made of aluminium and the treatment produces an oxide layer on the aluminium.
23. A method as claimed in claim 21, wherein the tube is made of aluminium and the treatment produces an nitride layer on the aluminium.
24. A method as claimed in any one of claims 15 to 23, wherein the whole of the tube is coated with the substance.
25. A method of making a measuring tube assembly for a flowmeter, the method being substantially as herein described with reference to, and as illustrated, by the accompanying drawings.
26. A measuring tube assembly made by a method as claimed in any one of claims 15 to 25.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9603298A GB2310287B (en) | 1996-02-16 | 1996-02-16 | Measuring tube assemblies and methods of making the same for electromagnetic flowmeters |
| DE1997105436 DE19705436C2 (en) | 1996-02-16 | 1997-02-13 | Measuring tube arrangement for electromagnetic flow meters and method for their production |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9603298A GB2310287B (en) | 1996-02-16 | 1996-02-16 | Measuring tube assemblies and methods of making the same for electromagnetic flowmeters |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9603298D0 GB9603298D0 (en) | 1996-04-17 |
| GB2310287A true GB2310287A (en) | 1997-08-20 |
| GB2310287B GB2310287B (en) | 2000-05-31 |
Family
ID=10788889
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9603298A Expired - Fee Related GB2310287B (en) | 1996-02-16 | 1996-02-16 | Measuring tube assemblies and methods of making the same for electromagnetic flowmeters |
Country Status (2)
| Country | Link |
|---|---|
| DE (1) | DE19705436C2 (en) |
| GB (1) | GB2310287B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101501456B (en) * | 2006-06-02 | 2013-11-20 | 恩德斯+豪斯流量技术股份有限公司 | In-line measuring device with measuring tube lined internally with polyurethane and method for manufacture thereof |
| EP2850439A4 (en) * | 2012-05-16 | 2016-01-27 | Rosemount Inc | Fastening system for magnetic flowmeter liner |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10053829C2 (en) * | 2000-10-30 | 2002-08-29 | Abb Patent Gmbh | Flow measuring |
| DE10338208B4 (en) * | 2003-08-20 | 2006-02-09 | Abb Patent Gmbh | Magnetically inductive flow measuring device |
| DE102006004757A1 (en) * | 2005-12-23 | 2007-07-05 | Abb Patent Gmbh | Eddy flow measuring device, has all parts, coming in contact with substance to be measured, of eddy flow meter, and parts are coated with base material, which is resistant to measuring material applicable in each case |
| DE102007005898A1 (en) * | 2007-02-01 | 2008-08-07 | Endress + Hauser Flowtec Ag | Device for measuring the volume or mass flow of a medium in a pipeline |
| DE102008057755B4 (en) * | 2008-11-17 | 2015-12-17 | Krohne Ag | Magnetic-inductive flowmeter |
| DE102014113843A1 (en) | 2014-09-24 | 2016-03-24 | Endress+Hauser Flowtec Ag | Measuring tube for a flowmeter and a magnetic-inductive flowmeter |
| DE102022119143A1 (en) | 2022-07-29 | 2024-02-01 | Endress+Hauser Flowtec Ag | Stainless steel product, field device and method of manufacture |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1119055A (en) * | 1964-10-10 | 1968-07-03 | Mawdsley S Ltd | Improvements in or relating to measuring instruments |
| GB1424050A (en) * | 1972-06-12 | 1976-02-04 | Sybron Corp | Electromagnetic flow transducers |
| US4181013A (en) * | 1976-07-23 | 1980-01-01 | Honeywell Inc. | Electrodes for an electromagnetic flow meter |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4327876C2 (en) * | 1993-08-19 | 2002-10-10 | Danfoss As | Measuring section for an electromagnetic flow meter and method for its production |
| ES2105828T3 (en) * | 1995-09-22 | 1997-10-16 | Flowtec Ag | PROCEDURE FOR MANUFACTURING A MEASURING TUBE FOR A FLOW-INDUCTIVE MAGNETIC COLLECTOR. |
-
1996
- 1996-02-16 GB GB9603298A patent/GB2310287B/en not_active Expired - Fee Related
-
1997
- 1997-02-13 DE DE1997105436 patent/DE19705436C2/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1119055A (en) * | 1964-10-10 | 1968-07-03 | Mawdsley S Ltd | Improvements in or relating to measuring instruments |
| GB1424050A (en) * | 1972-06-12 | 1976-02-04 | Sybron Corp | Electromagnetic flow transducers |
| US4181013A (en) * | 1976-07-23 | 1980-01-01 | Honeywell Inc. | Electrodes for an electromagnetic flow meter |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101501456B (en) * | 2006-06-02 | 2013-11-20 | 恩德斯+豪斯流量技术股份有限公司 | In-line measuring device with measuring tube lined internally with polyurethane and method for manufacture thereof |
| EP2850439A4 (en) * | 2012-05-16 | 2016-01-27 | Rosemount Inc | Fastening system for magnetic flowmeter liner |
Also Published As
| Publication number | Publication date |
|---|---|
| DE19705436A1 (en) | 1997-08-21 |
| GB2310287B (en) | 2000-05-31 |
| GB9603298D0 (en) | 1996-04-17 |
| DE19705436C2 (en) | 1999-10-21 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 732E | Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977) | ||
| 732E | Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977) | ||
| 732E | Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977) |
Free format text: REGISTERED BETWEEN 20110602 AND 20110608 |
|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20140216 |