CN105987728B

CN105987728B - Electromagnetic flowmeter

Info

Publication number: CN105987728B
Application number: CN201510084844.3A
Authority: CN
Inventors: 黄有军
Original assignee: Emerson Process Management Flow Technologies Co Ltd
Current assignee: Emerson Process Management Flow Technologies Co Ltd
Priority date: 2015-02-17
Filing date: 2015-02-17
Publication date: 2023-06-06
Anticipated expiration: 2035-02-17
Also published as: CN105987728A

Abstract

The present disclosure provides an electromagnetic flowmeter including a measurement conduit made of an insulating material whose magnetic permeability satisfies a predetermined condition; at least one pair of electrodes mounted on the measurement conduit and configured to sense an electrical potential induced in the fluid flowing through the measurement conduit to derive a flow rate of the fluid in the measurement conduit based on the induced electrical potential. An electromagnetic flowmeter according to the present disclosure has at least one of the following benefits: the novel heat insulation material does not need a lining, is convenient to install, has lighter weight and very high strength, and has very good corrosion resistance, electrical insulation performance and heat insulation performance.

Description

Electromagnetic flowmeter

Technical Field

The present disclosure relates generally to the field of industrial control, and more particularly, to flow meters for sensing and measuring the flow of fluids in industrial process devices.

Background

The electromagnetic flowmeter is a flowmeter for measuring flow according to faraday's law of electromagnetic induction, and calculates the flow velocity of fluid in a pipeline by measuring induced electromotive force generated on electrodes on both sides of a measuring conduit when the fluid moves in a magnetic field to cut magnetic lines of force, thereby determining the flow. Electromagnetic flowmeters are now widely used in industrial processes because of their unique advantages.

Electromagnetic flowmeters typically include a measurement conduit, measurement electrodes, an electromagnetic coil located outside the measurement conduit, and a controller. The measuring duct is usually made of a metal material, and when the measuring electrode is assembled, holes need to be drilled in the metal measuring duct, and in addition, in order to prevent the induced potential from being shorted by the pipe wall inside the metal measuring duct, an insulating inner layer exposing only the measuring electrode needs to be arranged inside the measuring duct.

However, the existing electromagnetic flowmeter may cause unstable meter output and even meter damage in the event of damage to the insulating lining, and there is a risk of fluid leakage at the electrode mounting holes.

Disclosure of Invention

It is an object of the present disclosure to provide an electromagnetic flowmeter that overcomes at least one of the above-mentioned drawbacks of the prior art.

According to one aspect of the present disclosure, there is provided an electromagnetic flowmeter including a measurement conduit made of an insulating material whose magnetic permeability satisfies a predetermined condition; and at least one pair of electrodes mounted on the measurement conduit and configured to sense an electrical potential induced in the fluid flowing through the measurement conduit to derive a flow rate of the fluid based on the induced electrical potential for the electrical flowmeter.

Preferably, the predetermined condition is that the permeability of the insulating material is set such that measuring the magnetic field strength within the catheter does not affect the sensing of the induced potential.

Preferably, the insulating non-magnetically permeable material is made of an insulating non-magnetically permeable material, in particular glass fibre reinforced plastic. Preferably, the measurement catheter is integrally formed with at least one pair of electrodes.

In one possible example, the electromagnetic flowmeter further comprises a magnetic field generating element coupled to the outer sidewall of the measurement conduit by a connection unit and configured to generate a magnetic field for application to the fluid flowing through the measurement conduit.

Preferably, at least a portion of the connection unit is integrally formed with the measurement catheter.

In one possible example, wherein the electromagnetic flowmeter further comprises a shielding member provided on the measurement conduit at a position corresponding to the magnetic field generating element, wherein the shielding member comprises two clamping sleeves each having a semicircular cross section and being connected to each other and detachably provided at an outer periphery of the magnetic field generating element, and a magnetic field shielding layer covering an entire inner surface of each clamping sleeve including the inner side surface and the two inner end surfaces.

Preferably, the shielding member is made of a non-magnetically conductive material, in particular glass fibre reinforced plastic.

In one possible example, the electromagnetic flowmeter further comprises a controller configured to derive a flow rate of the fluid based on the electrical potentials sensed by the at least one pair of electrodes, wherein the controller has a glass fiber reinforced plastic housing.

Drawings

The present disclosure may be better understood by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify the same or similar elements throughout. Wherein:

FIG. 1 is a schematic perspective view of an electromagnetic flow meter according to an embodiment of the present disclosure;

FIG. 2 is a cross-sectional view of a measurement conduit of an electromagnetic flow meter along the axis I-I' of FIG. 1 and through a reference plane (not shown) of a measurement electrode in accordance with an embodiment of the disclosure;

FIG. 3 is a perspective schematic view of a measurement conduit of an electromagnetic flow meter according to an embodiment of the disclosure;

fig. 4 is an assembly view of a magnetic field generating element of an electromagnetic flow meter according to an embodiment of the present disclosure;

fig. 5 is an assembly view of a shield component of an electromagnetic flow meter according to an embodiment of the present disclosure;

FIG. 6 is a cross-sectional view of an electromagnetic flow meter configured with a magnetic field shielding layer of the electromagnetic flow meter along the axis P-P' of FIG. 5 and through a connection face of a clamping sleeve in accordance with an embodiment of the disclosure; and

fig. 7 is a schematic view of a magnetic field shielding layer disposed in a first clamping sleeve of an electromagnetic flowmeter according to an embodiment of the present disclosure.

Detailed Description

Embodiments of the present disclosure are described below with reference to the accompanying drawings. It should be noted that for the sake of clarity, the illustration and description of components and processes known to those skilled in the art, which are not germane to the present disclosure, have been omitted from the drawings and description.

The inventors of the present application found that: the insulating lining inside the metal measuring conduit may wear, peel, or even fall off due to the high temperature, impact, corrosion, etc. of the fluid flowing through the measuring conduit. In this case, the induced potential may be short-circuited by the wall of the inside of the metal measuring tube, and in addition, in the case where the insulating lining located in the vicinity of the electrode is broken, the fluid may leak from the electrode mounting hole, causing unstable meter output and even damage.

To this end, according to an embodiment of the present invention, there is provided an electromagnetic flowmeter including: a measuring duct made of an insulating material whose magnetic permeability satisfies a predetermined condition; and further comprising at least one pair of electrodes mounted on the measurement conduit and configured to sense an electrical potential induced in the fluid flowing through the measurement conduit to derive a flow rate of the fluid based on the induced electrical potential for the electrical flowmeter.

Various specific implementations of the electromagnetic flowmeter described above are shown in the various figures and described in greater detail below.

Fig. 1 is a perspective schematic view of an electromagnetic flow meter according to an embodiment of the present disclosure, and fig. 2 is a cross-sectional view of a measurement conduit of the electromagnetic flow meter along the axis I-I' of fig. 1 and through a reference plane (not shown) of a measurement electrode according to an embodiment of the present disclosure. The electromagnetic flowmeter 100 disclosed in this example includes: a measuring catheter 10 made of an insulating, non-magnetically conductive material; at least one pair of

electrodes

21,22 is mounted on the measurement catheter 10 and is configured to sense an electrical potential induced in the fluid flowing through the measurement catheter 10 to derive a flow rate of the fluid based on the induced electrical potential for the electrical flowmeter 100.

The measuring conduit 10 has an inlet 11 and an outlet 12. The cross-sectional shape of the inlet 11 and outlet 12 may be adapted to the pipe to be tested at the junction. In this embodiment, the inlet 11 and outlet 12 are substantially circular in cross-section. The measurement portion is provided between the inlet 11 and the outlet 12 of the measurement conduit 10, and parameters such as shape and length of the measurement portion are designed based on the flow rate, the flow velocity, and other factors of the fluid to be measured, and are well known to those skilled in the art, and will not be described herein.

The measuring conduit 10 can be connected to the pipe under test in a clamping manner with the aid of a calibration ring by means of washers and with the aid of connectors such as bolts and nuts, or can be connected to the pipe under test by means of connecting flanges welded at the inlet 11 and the outlet 12. Those skilled in the art will appreciate that the manner in which the measurement catheter 10 is attached to the site to be measured is not limited to that described in the embodiments of the present disclosure.

In the present embodiment, the measuring catheter 10 is made of an insulating non-magnetic conductive material, but is not limited thereto. It will be appreciated by those skilled in the art that it is also possible to make the measuring catheter 10 from an insulating material having a low magnetic permeability, as long as the insulating material from which the measuring catheter 10 is made meets predetermined conditions. The predetermined conditions described above include: so that the permeability of the insulating material is set to ensure that the magnetic field strength inside the measurement catheter 10 is not reduced by the magnetic field that may be generated by the measurement catheter 10 itself, affecting the sensing of the induced potential. In this way, in the case where the measuring duct 10 is made of a material satisfying predetermined conditions, such as insulating non-magnetic permeability (or low magnetic permeability), it is not necessary to provide an insulating lining on the inside of the measuring duct 10. Preferably, the measuring catheter 10 is made of a glass fibre reinforced plastic material. The glass fiber reinforced plastic material has strong corrosion resistance and good heat insulation performance, and meanwhile, as the glass fiber reinforced plastic material is insulating and non-magnetic, an insulating lining is not required to be arranged in the measuring conduit 10, so that adverse effects caused by using the insulating lining are avoided, and the reliability of the electromagnetic flowmeter 100 is improved.

As shown in fig. 2, at least one pair of

electrodes

21,22 is provided on the measurement catheter 10, the

electrodes

21,22 being used for sensing the electric potential induced in the fluid due to the applied magnetic field and the flow of the fluid. One end of each of the

electrodes

21,22 is exposed from the inner wall of the measuring catheter 10 to sense the electric potential generated by the fluid, and the other end extends from the outer wall of the measuring catheter 10 to be electrically connected to the controller 40 (or wiring mount) through an electrode lead (not shown).

In one possible example, the measurement catheter 10 is integrally formed with a pair of

electrodes

21, 22. Unlike the conventional art that holes are drilled in a metal measuring tube to assemble the electrodes, in this embodiment, since the

electrodes

21,22 are integrally formed with the measuring tube 10, the

electrodes

21,22 do not need to be drilled in the measuring tube 10 during assembly, so that there is substantially no gap between the

electrodes

21,22 and the measuring tube 10, thereby preventing leakage of fluid from the electrode mounting holes and improving the reliability of the electromagnetic flowmeter 100.

Fig. 3 is a schematic view of a measurement conduit of an electromagnetic flowmeter according to an embodiment of the present disclosure, and fig. 4 is an assembly view of a magnetic field generating element of an electromagnetic flowmeter according to an embodiment of the present disclosure. In the present embodiment, the magnetic

field generating elements

31,32 are used to generate a magnetic field at the measurement portion of the measurement catheter 10. For example, the magnetic

field generating elements

31,32 may be

electromagnetic coils

31, 32. The number, size and shape of the

electromagnetic coils

31,32 required may be selected according to the shape, length and the like of the measuring catheter 10 and the

electromagnetic coils

31,32 may be coupled to the outer side wall of the measuring catheter 10 by means of a connection unit provided on the measuring catheter 10.

An exemplary embodiment of securing a magnetic field generating element, such as a solenoid coil, to a measuring catheter is described below in connection with fig. 3 and 4, and in the art the connection unit includes a plurality of stainless steel threaded sleeves 60 embedded in the measuring catheter 10, straps 62 securing the

solenoid coils

31,32, and fasteners 61 as shown in fig. 3. In fig. 4, the

electromagnetic coils

31,32 are saddle-shaped coils, and the tie 62 securing the electromagnetic coil 31 secures the electromagnetic coil 31 to the stainless steel sleeve 60 on the outer side wall of the measuring catheter 10 by means of fasteners such as pins, screws, etc., thus securing the

electromagnetic coils

31,32 in the desired position. In one possible example, the stainless steel screw sleeve 60 and the measuring tube 10 and the pair of

electrodes

21,22 may be integrally formed, for example, in one injection molding process, which not only simplifies the manufacturing process, but also makes the assembling process simple, and welding or drilling operations or the like are not required at the time of assembling, thereby preventing leakage of fluid from the electrode mounting holes and improving the reliability of the electromagnetic flowmeter 100.

The controller 40 is used to derive the flow rate of the fluid flowing through the measurement catheter 10 based on the potentials sensed by the

electrodes

21, 22. In a specific example, the controller 40 may be provided integrally (as shown in fig. 1) or separately by means of a wiring mount (not shown). Preferably, the housing of the controller 40 or the housing of the wire mount may be made of a glass fiber reinforced plastic material.

In one possible example, shielding members 50 for shielding interference and enhancing an internal magnetic field are provided on the outer circumferences of the

electromagnetic coils

31, 32. Fig. 5 is an assembly view of a shielding member of an electromagnetic flowmeter according to an embodiment of the present disclosure, and as shown in fig. 5, a shielding member 50 is provided on the measurement duct 10 at a position corresponding to the

electromagnetic coils

31,32 and entirely surrounds the outer periphery of the measurement duct 10. The shielding member 50 includes two

grip sleeves

51,52 and a magnetic field shielding layer 70 covering the inner surfaces of the

grip sleeves

51, 52. Wherein the first and

second clamping sleeves

51 and 52 have a semicircular cross section, a mounting seat 515 is provided at the top of the first clamping sleeve 51, and an electrode lead extends upward along a passage provided inside the mounting seat 515 and is connected to a controller 40 (not shown in fig. 5) or a wire mounting seat provided on the mounting seat 515. The first and

second clamping sleeves

51,52 are connected to each other and are detachably provided at the outer periphery of the magnetic field generating element (not shown in fig. 5), for example, by means of fasteners.

Preferably, the first and

second clamping sleeves

51,52 including the mounting base 515 are made of glass fiber reinforced plastic materials, and the glass fiber reinforced plastic materials have high strength and are connected in opposite directions to form a closed space, so that the measuring catheter 10, the

electromagnetic coils

31,32, the magnetic field shielding layer 70 and other elements arranged in the space can be well protected. In addition, since the electromagnetic flowmeter 100 as a whole (including the measuring conduit 10, the first and

second clamping sleeves

51,52, and the housing of the controller 40) is made of glass fiber reinforced plastic materials, the electromagnetic flowmeter 100 does not need to be provided with a lining, and has light weight, high strength, good corrosion resistance, electrical insulation property, and heat insulation property.

Fig. 6 is a cross-sectional view of an electromagnetic flow meter configured with a magnetic field shielding layer of the electromagnetic flow meter along the axis P-P' of fig. 5 and through the connection face of the clamping sleeve in accordance with an embodiment of the disclosure. As shown in fig. 6, the magnetic field shielding layer 70 is provided on the outer periphery of the electromagnetic coil 31 and between the first clamping sleeve 51 and the electromagnetic coil 31. Although not shown in the drawings, similarly, a magnetic field shielding layer 70 is also provided between the second clamping sleeve 52 and the electromagnetic coil 32. Preferably, the magnetic field shielding layer 70 is made of a material having good magnetic permeability, such as electrical steel, silicon steel, or the like.

Fig. 7 is a schematic view of a magnetic field shielding layer of an electromagnetic flowmeter according to an embodiment of the present disclosure disposed in a first clamping sleeve 51, as shown in fig. 7, a magnetic field shielding layer 70 made of an electrical steel material covering the entire inner surface of the first clamping sleeve 51 including an inner side surface 510 and two inner end surfaces 511, 512. Although not shown in fig. 6, similarly, a magnetic field shielding layer 70 (not shown in fig. 7) covering the entire inner surface of the second clamping sleeve 52 including the inner side surface and both inner end surfaces may be similarly provided in the second clamping sleeve 52. In this way, in the case of assembling the first clamping sleeve 51 and the second clamping sleeve 52 to each other to form the shielding member 50, the magnetic field shielding layers 70 (not shown in fig. 7) in the first clamping sleeve 51 and the second clamping sleeve 52 also form a closed circuit, so that the strong magnetic field generated by the

electromagnetic coils

31,32 at the measurement catheter 10 is kept as much as possible within the closed circuit formed by the magnetic field shielding layers 70 provided in the first clamping sleeve 51 and the second clamping sleeve 52 without leaking to the outside space, thereby reducing the interference of the strong magnetic field generated by the

electromagnetic coils

31,32 at the measurement catheter 10 to other detection circuits of the electromagnetic flowmeter 100.

In addition, in the case where the magnetic field shielding layer 70 is provided, most of the magnetic field generated by the magnetic

field generating elements

31,32 is confined inside the measurement catheter 10 surrounded by the first and

second clamping sleeves

51,52, and thus, the magnetic field strength inside the measurement catheter 10 is enhanced to some extent.

While the disclosure has been disclosed by the foregoing description of specific embodiments thereof, it will be understood that various modifications, improvements, or equivalents may be devised by those skilled in the art that will fall within the spirit and scope of the appended claims. Such modifications, improvements, or equivalents are intended to be included within the scope of this disclosure.

Claims

1. An electromagnetic flowmeter (100), comprising:

a measuring catheter (10) made of an insulating material, the permeability of which meets a predetermined condition; and

at least one pair of electrodes (21, 22), the at least one pair of electrodes (21, 22) being mounted on the measurement conduit (10) and configured to sense an electrical potential induced in a fluid flowing through the measurement conduit (10) for the electromagnetic flow meter (100) to derive a flow rate of the fluid based on the induced electrical potential,

wherein the measuring catheter (10) is integrally formed with the at least one pair of electrodes (21, 22),

wherein the electromagnetic flowmeter (100) further comprises a magnetic field generating element (31, 32), the magnetic field generating element (31, 32) being coupled to an outer side wall of the measuring conduit (10) by a connection unit (60, 61, 62) and being configured to generate a magnetic field for application to the fluid flowing through the measuring conduit (10),

wherein the connection unit (60, 61, 62) comprises a binding belt (62), a fastening piece (61) and a plurality of stainless steel threaded sleeves (60) embedded into the measuring catheter (10),

wherein the tie (62) secures the magnetic field generating element (31, 32) to the stainless steel sleeve (60) by means of the fastener (61), an

Wherein the stainless steel screw sleeve (60) and the measuring catheter (10) are integrally formed.

2. The electromagnetic flowmeter (100) of claim 1, the predetermined condition being that a permeability of the insulating material is set such that a magnetic field strength within the measurement conduit (10) does not affect sensing of the induced electrical potential.

3. The electromagnetic flowmeter (100) of claim 1 or 2, wherein the measurement conduit (10) is made of an insulating non-magnetically permeable material.

4. An electromagnetic flowmeter (100) according to claim 3, wherein the measurement conduit (10) is made of glass fiber reinforced plastic.

5. The electromagnetic flowmeter (100) of claim 1, wherein the electromagnetic flowmeter (100) further comprises a shielding member (50), the shielding member (50) being disposed on the measurement conduit (10) at a position corresponding to the magnetic field generating element (31, 32), the shielding member (50) comprising two clamping sleeves (51, 52) and a magnetic field shielding layer (70), wherein each clamping sleeve (51, 52) is semicircular in cross section, and the two clamping sleeves (51, 52) are connected to each other and detachably disposed on an outer periphery of the magnetic field generating element (31, 32), the magnetic field shielding layer (70) covering an entire inner surface of each clamping sleeve (51, 52) including an inner side surface (510) and two inner end surfaces (511, 512).

6. The electromagnetic flowmeter (100) of claim 5, wherein the two clamp sleeves (51, 52) are made of a non-magnetically permeable material.

7. The electromagnetic flowmeter (100) of claim 6, wherein the two clamping sleeves (51, 52) are made of glass fiber reinforced plastic.

8. The electromagnetic flow meter (100) of claim 1 or 2, wherein the electromagnetic flow meter (100) further comprises a controller (40), the controller (40) being configured to derive the flow rate of the fluid based on the electrical potential induced by the at least one pair of electrodes (21, 22), wherein the controller (40) has a glass fiber reinforced plastic housing.