WO2018229523A1

WO2018229523A1 - An electromagnetic flowmeter assembly

Info

Publication number: WO2018229523A1
Application number: PCT/IB2017/053449
Authority: WO
Inventors: Ravikumar KANDASAMY; Subhashish Dasgupta; Rock-RenDong LI; Xiaoxiang ZHOU; Kevin-Renyi QU; Vinay KARIWALA
Original assignee: Abb Schweiz Ag
Priority date: 2017-06-12
Filing date: 2017-06-12
Publication date: 2018-12-20
Also published as: DE212017000334U1; CN211978009U

Abstract

The present invention relates to an electromagnetic flowmeter assembly. The electromagnetic flowmeter assembly comprises a first conduit of a first material and at least one end conduit of a second material, wherein at least one end of the first conduit is connected with the at least one second conduit. A coil is mounted on the first conduit for generating electromagnetic fields that interact with the fluid passing through the electromagnetic flowmeter. A pair of electrodes mounted on the first conduit for measuring potential difference generated by the interaction of electromagnetic field in the fluid to determine the flow of fluid in the electromagnetic flowmeter. In this electromagnetic flowmeter assembly, a first dimension of the first conduit on a first axis parallel to the direction of the flow of the fluid is substantially equal to a second dimension of the first conduit on an axis transverse to the first axis.

Description

AN ELECTROMAGNETIC FLOWMETER ASSEMBLY

FIELD OF THE INVENTION

[001] The present invention relates generally electromagnetic flowmeters and more particularly to an electromagnetic flowmeter assembly with insulated connecting pipes.

BACKGROUND OF THE INVENTION

[002] Electromagnetic flowmeters have been popularly used for measuring flow of fluids through a conduit or pipe. Electromagnetic flowmeters measure the flow of fluids in a non-invasive manner with high reliability and accuracy in measurements.

[003] A typical electromagnetic flowmeter works on Faraday's law of electromagnetic induction. An electromagnetic field is imposed within a flow pipe or conduit having a flow of fluid with a certain level of conductivity. Electromotive force (EMF) induced as a result of the interaction of the electromagnetic field with fluid molecules (ions in the fluid), is measured using electrodes provided at the pipe side walls. The measured EMF is proportional to the flowrate and thus used to measure flowrate. While electromagnetic flowmeters are attractive given that they are non-invasive, accurate and simplistic in construction, it is desirable to reduce the material cost and/or weight of the flowmeters, especially for application in large diameter flow pipes without scarifying the accuracy.

[004] The components which influence the overall EM flow meter cost are: (a) coil (electromagnet), (b) non-magnetic pipe (Stainless steel) and (c) Ferro-magnetic or carbon steel outer cover. It is difficult to reduce the coil length without scarifying the sensitivity and accuracy of the flow meter. It may require special coil shape to compensate the performance. Other alternative to reduce the cost of the flow meter is reduction of overall flow meter length.

[005] Typically length of the EM flow meter is at least 1.3 times of the diameter of the flow tube. Reducing the flow meter length may lead to saving the overall cost of the flow meter. However, flowmeter sensitivity and accuracy gets affected when the reduced length flowmeter is connected to various conducting end (customer) pipes due to magnetic and electric field leakage Hence there is a need for an electromagnetic flowmeter that can be used for measuring flow rate of fluids which provides for accurate measurements even with reduced length of the electromagnetic flowmeter.

SUMMARY

[006] The above-mentioned shortcomings, disadvantages and problems are addressed herein which will be understood by reading and understanding the following specification.

[007] In one aspect, the present invention provides an electromagnetic flowmeter assembly for measuring flow rate of a fluid flowing there through, the electromagnetic flowmeter assembly comprising: a first conduit of a first material and at least one end conduit of a second material, wherein at least one end of the first conduit is connected with the at least one end conduit; at least one coil mounted on the first conduit for generating electromagnetic fields that interact with the fluid passing through the first conduit; a pair of electrodes mounted on the first conduit for measuring potential difference generated by the interaction of electromagnetic field in the fluid to determine the flow of fluid in the first conduit; and wherein a first dimension of the first conduit on a first axis parallel to the direction of the flow of the fluid is substantially equal to a second dimension of the first conduit on an axis transverse to the first axis.

[008] In an embodiment the electromagnetic flowmeter assembly wherein the first material and the second material have different magnetic permeability.

[009] In an embodiment the electromagnetic flowmeter assembly wherein the second conduit is made of an insulating material.

[0010] In an embodiment the electromagnetic flowmeter assembly wherein the coil is coupled with an annular magnetic element having a magnetic permeability higher than that of the first material or the second material. [0011] In an embodiment the electromagnetic flowmeter assembly as mentioned herein above further comprising an excitation unit to excite the at least one coil for generating an electromagnetic field that interact with the fluid passing through the electromagnetic flowmeter, wherein the excitation unit is controlled by a processing unit.

[0012] In an embodiment, the electromagnetic flowmeter assembly mentioned herein above further comprises a processing unit, wherein the processing unit acquires signals from the electrodes and processes the signal for measurement.

[0013] In an embodiment, the electromagnetic flowmeter assembly further comprising a display for indicating the measured flow rate of fluid.

[0014] In an embodiment, the electromagnetic flowmeter wherein measured flow rate of fluid is transmitted to a remote control centre of the electromagnetic flowmeter for storage or analysis.

[0015] In an embodiment, the electromagnetic flowmeter assembly further comprising an inner protrusion on the at least one end conduit of a second material for interacting with the flow of fluid passing there through.

[0016] In an embodiment, the electromagnetic flowmeter assembly wherein the protrusion is placed at an end first facing the flow of the fluid.

BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 illustrates an electromagnetic flowmeter assembly 100;

[0018] Figure 2, illustrates a side view of the electromagnetic flowmeter assembly; and [0019] Figure 3, illustrates an electromagnetic flowmeter assembly with an inner protrusion.

DETAILED DESCRIPTION

[0020] The present invention is related to an electromagnetic flowmeter assembly with insulated connecting pipes. Reduction of overall flow meter length may also result in reduction in cost of the electromagnetic flowmeters. Typically length of the electromagnetic flowmeter is at least 1.3 times of the diameter of the flow pipe. Reducing the flow meter length from 1.3 times of the diameter to nearly equal to the diameter of the flow pipe may lead to savings in overall cost of the flow meter. However electromagnetic flowmeter sensitivity and accuracy gets affected when the flow meter with reduced length is connected to various conducting end (customer) pipes due to magnetic and electric field leakage.

[0021] In order to improve the sensitivity and accuracy of the flow meter the present invention provides for using connecting pipes made of an insulating material at two connectable ends of the flow pipe of electromagnetic flowmeter. Additionally, the present invention provides for using a high permeability material /magnetic field concentrator (a magnetic element) to be positioned over the coils which concentrates the magnetic field. The magnetic element or magnetic field concentrator is annularly positioned in the form of a ring along with the coil. It helps to minimize the magnetic and electric field leakages and improve the sensitivity and accuracy of the flow meter. Also in this invention, flow disturbance may be created at the inlet and /or outlet of the flow meter. The flow disturbance reduces the leakage of induced electromotive force and improves the accuracy of the flow meter.

[0022] In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific embodiments, which may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments, and it is to be understood that other embodiments may be utilized. The following detailed description is, therefore, not to be taken in a limiting sense. [0023] Figure 1 illustrates an electromagnetic flowmeter assembly 100. Figure 1 shows an electromagnetic flowmeter assembly, which comprises a flow pipe/first conduit 110 through which fluid flows, a coil 120 for generating electromagnetic fields that interact with the fluid passing through the flow pipe/first conduit 110, a pair of electrodes (130- referencing an electrode shown in the figure, 140 referencing an electrode not visible in the figure but present at the opposite side facing the electrode 130) placed with a gap between the electrodes for measuring potential difference generated by the interaction of electromagnetic fields in the fluid in the flow pipe 110.

[0024] The first conduit 110 is flanked on its both connectable ends with two end conduits

150 and 160. The first conduit 110 may be flanked by only one conduit on one side, however for exemplary purposes, a preferred embodiment with two end conduits (150 and 160) is shown in Figure 1. The first conduit 110 and the end conduits (150 and 160) are composed of different materials. As shown in Figure 1, the coil is mounted on the first conduit 110, a pair of electrodes (130 and 140) mounted on the first conduit 110 and a first dimension of the first conduit 110 on a first axis parallel to the direction of the flow of the fluid is substantially equal to a second dimension of the first conduit 110 on an axis transverse to the first axis. For example, the first dimension of the first conduit 110 is the length of the first conduit where length refers to the extent of the first conduit 110 from its one end to its other end in the direction of flow parallel to the first axis. And the second dimension of the first conduit 110 on an axis transverse to the first axis is the diameter of the first conduit. The length or first dimension of the first conduit 110 is almost equal or equal to the diameter or second dimension of the first conduit 110. This may result is reducing the overall cost of the electromagnetic flowmeter.

[0025] The end conduits 150 and 160 on the two connectable ends are made of an insulating material, for example Teflon. Due to the insulating nature of the end conduits, the magnetic field or electric filed leakage to a periphery outside the first conduit is minimized.

[0026] Additionally, magnetic flux and electric current leakage can be minimized or avoided by coupling a high permeable material or magnetic element (return iron) to the coil. As shown in figure 1, the coil is further coupled with a magnetic element/return iron 170 having a magnetic permeability higher than that of the first material or the second material. As shown in figure 1 , the magnetic element 170 is annularly placed coupled/attached to the coil in the form of a ring circumnavigating the periphery of the first conduit. The magnetic element concentrates the magnetic field and allows for accurate measurements as it leads to higher electric field concentration at the center of the measurement realm and less electric field at the ends of the electromagnetic flowmeter.

[0027] Figure 2, illustrates a side view of the electromagnetic flowmeter with the first conduit

110 and the two end conduits 150 and 160 flanked on both sides and flanges 200 for connecting the end conduits with the first conduit and another set of flanges 210 on the end conduits 150 and 160 for connecting to customer pipes. The connection between the first conduit and end conduits may be done in a manner known to the person skilled in the art.

[0028] Figure 3, illustrates an embodiment wherein an inner protrusion is provided on the end conduit made of the second material for interacting with the flow of fluid passing there through. The inner protrusion is placed at an end first facing the flow of the fluid. This inner protrusion causes an obstruction in flow of the fluid passing through the electromagnetic flowmeter. Hence, Figure 3 shows the electromagnetic flowmeter assembly as shown in Figure 1, with an additional inner protrusion 300 for flow obstruction. Flow separation is induced between the fluid flowing in the flow pipe and the customer pipe leading for minimization of the electrical field leakage. In an embodiment, a disturbance in flow can be induced using an orifice introduced at an inlet and exit of the flow pipe to create flow separation. It may be known to the person skilled in the art that flow obstruction in a flow pipe can be introduced in various techniques.

[0029] In an embodiment of the electromagnetic flowmeter, instead of using end conduits made of an insulating material, a conducting liner may be introduced in at least one end of the first conduit. Due to the presence of the conducting liner a buffering effect of minimized leakage of magnetic flux or electric field from the realm of measurement to customer pipes can be realized.

[0030] In an embodiment, the electromagnetic flowmeter assembly further comprises an excitation unit to excite the at least one coil for generating an electromagnetic field that interact with the fluid passing through the electromagnetic flowmeter, wherein the excitation unit is controlled by a processing unit. The electromagnetic flowmeter for exciting the coils for producing electromagnetic fields have a suitable power source and electronics circuitries for making potential difference measurements and display/transmitting the measured values. In an embodiment, the electromagnetic flowmeter assembly mentioned herein above further comprises a processing unit, wherein the processing unit acquires signals from the electrodes and processes the signal for measurement.

[0031] In an embodiment, the electromagnetic flowmeter wherein measured flow rate of fluid is transmitted to a remote control centre of the electromagnetic flowmeter for storage or analysis. In an embodiment, the electromagnetic flowmeter can comprise a display for indicating the determined flow of fluid in the flow pipe.

[0032] In an embodiment, the electromagnetic flowmeter assembly wherein the determined flow of fluid in the flow pipe (measured potential difference between the electrodes) is transmitted to a remote control center of the electromagnetic flowmeter.

In an embodiment, the electromagnetic flowmeter is Internet of Things (IOT) enabled for providing remote controlling, better visibility of the working of the electromagnetic flowmeter, providing real time information to software systems and other surrounding IOT enabled systems.

[0033] This written description uses examples to describe the subject matter herein, including the best mode, and also to enable any person skilled in the art to make and use the subject matter. The patentable scope of the subject matter is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.

Claims

1. An electromagnetic flowmeter assembly (100) for measuring flow rate of a fluid flowing there through, the electromagnetic flowmeter assembly (100) comprising: a first conduit (110) of a first material and at least one end conduit (150) of a second material, wherein at least one end of the first conduit (110) is connected with the at least one end conduit (150); at least one coil (120) mounted on the first conduit for generating electromagnetic fields that interact with the fluid passing through the first conduit (110); a pair of electrodes (130 and 140) mounted on the first conduit (110) for measuring potential difference generated by the interaction of electromagnetic field in the fluid to determine the flow of fluid in the first conduit (110); and wherein a first dimension of the first conduit (110) on a first axis parallel to the direction of the flow of the fluid is substantially equal to a second dimension of the first conduit (110) on an axis transverse to the first axis.

2. The electromagnetic flowmeter assembly as claimed in claim 1 , wherein the first material and the second material have different magnetic permeability.

3. The electromagnetic flowmeter assembly as claimed in claim 1, wherein the second conduit is made of an insulating material.

4. The electromagnetic flowmeter assembly as claimed in claim 1 , wherein the coil is coupled with an annular magnetic element having a magnetic permeability higher than that of the first material or the second material.

5. The electromagnetic flowmeter assembly as claimed in claim 1, further comprising an excitation unit to excite the at least one coil for generating an electromagnetic field that interact with the fluid passing through the electromagnetic flowmeter, wherein the excitation unit is controlled by a processing unit.

6. The electromagnetic flowmeter assembly as claimed in claim 1 , further comprises a processing unit, wherein the processing unit acquires signals from the electrodes and processes the signal for measurement.

7. The electromagnetic flowmeter assembly as claimed in claim 1, further comprising a display for indicating the measured flow rate of fluid.

8. The electromagnetic flowmeter assembly as claimed in claim 1, wherein measured flow rate of fluid is transmitted to a remote control centre of the electromagnetic flowmeter for storage or analysis.

9. The electromagnetic flowmeter assembly as claimed in claim 1, further comprising an inner protrusion on the at least one end conduit of a second material for interacting with the flow of fluid passing there through.

10. The electromagnetic flowmeter assembly as claimed in claim 9, wherein the protrusion is placed at an end first facing the flow of the fluid.