CN101699227A - Capacitance-type electromagnetic flow transducer with rectangular cross section structure - Google Patents
Capacitance-type electromagnetic flow transducer with rectangular cross section structure Download PDFInfo
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- CN101699227A CN101699227A CN200910236291A CN200910236291A CN101699227A CN 101699227 A CN101699227 A CN 101699227A CN 200910236291 A CN200910236291 A CN 200910236291A CN 200910236291 A CN200910236291 A CN 200910236291A CN 101699227 A CN101699227 A CN 101699227A
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Abstract
The invention relates to a capacitance-type electromagnetic flow transducer with rectangular cross section structure, comprising a measuring tube, an electrode, a shielding electrode and magnet exciting coils. The capacitance-type electromagnetic flow transducer is characterized in that the measuring tube has the rectangular cross section structure and is made of insulation material, and measured fluid flows through the measuring tube; the electrode is a rectangular metal sheet and consists of a left electrode and a right electrode which are attached at the outer side of the measuring tube in a symmetrical way; the shielding electrode consists of a left shielding electrode and a right shielding electrode, wherein the left shielding electrode is positioned at the outer side of the left electrode, the right shielding electrode is arranged at the outer side of the right electrode, and the electrodes are surrounded inside the shielding electrodes; and the magnet exciting coils are positioned at the upper and the lower sides of the measuring tube and combined with the uniform magnetic field generated by an exciting circuit, and the magnetic field direction of the magnet exciting coils can be in orthogonality with the connecting line between the centers of the two electrodes. The capacitance-type electromagnetic flow transducer can be used for measuring the output without being affected by the flow rate distribution, and avoids the problems of the influence such as corrosion, pollution and leakage of the electrodes as well as slurry fluid noise, etc.
Description
Technical field
The present invention relates to a kind of electromagnetic flowmeter, particularly relate to a kind of electromagnet flow meter sensor.
Background technology
Electromagnetic flow transducer is the device that physical quantity " flow " is transformed to another physical quantity " electromotive force ", even the conduction working fluid produces the device of induced electromotive force signal.Fundamental is made up of one or more pairs of electrodes of measuring tube, magnetic field production part and pickoff signals.
At present, the sensor of electromagnetic flowmeter generally adopts circular tube structure, the method for electromagnetically measuring CN1097868 of for example Chinese publication electromagnetic flowmeter CN1108385, electromagnetic flowmeter CN1131273, electromagnetic flowmeter and flow etc.Electromagnetic flow transducer is installed in the pipeline, and conducting liquid flows through electromagnetic flow transducer.Electromagnetic flux converter provides exciting current to field coil, produces magnetic field in electromagnetic flow transducer, and moving fluid cutting magnetic line potential electrode will produce induced electromotive force.For said structure, arbitrarily some fluid infinitesimals flow through measuring tube interior certain when a bit, the induction electromotive force of generation not only is directly proportional with the flow velocity of this point and the magnetic field of this point, and is directly proportional with the weighting function of this point.For the uniform electromagnetic flow transducer in long cartridge type magnetic field, when flow velocity is a rotational symmetry when distributing, because of the weighting function role just in time equivalence be 1, induction electromotive force and the strict linear dependence of flow velocity mean value that the measuring tube cross section produces.When flow velocity is a non-rotational symmetry when distributing,, cause measuring error because the weighting function role can not be equivalent to 1.
In order to reduce the adverse effect of velocity flow profile in the pipe, also can apply weight magnetic field.B=B is pressed in circular pipe electromagnetic flow transducer magnetic field
0/ W
yRule (the B wherein that distributes
0Be the magnetic induction density at electrode kernel of section of living in place, W
yBe weighting function), i.e. weighting function W
yBe worth big place, the magnetic induction density B of design is weak, weighting function W
yBe worth little place, the magnetic induction density B of design is strong, makes magnetic induction density and weighting function W
yProduct at any point is a constant, and then in the round pipe in such regularity of distribution magnetic field, the induction electromotive force between point electrode is directly proportional with the mean value of cross-sectional flow, and irrelevant with the velocity flow profile in the section.That is to say, adopt the electromagnetic flow transducer that meets weight Distribution of Magnetic Field rule, when fluid velocity changed, induction electromotive force only was directly proportional with flow velocity mean value, and irrelevant with the distribution of speed.But in actual design, the magnetic field that distributes by weighting function does not exist, and approaches desirable weight magnetic field though can design magnetic field, still has certain error.
Introduced a kind of measuring tube of square-section in " electromagnetic flowmeter " that Cai Wuchang etc. write (Sinopec publishing house 2004 March the 1st edition) book.The both sides up and down of the measuring tube of square-section are lined with in the electrically insulating substrate, and the inwall of the right and left is equipped with the electrode that sheet metal is made.The line of electric force of measuring tube internal induction electromotive force all is parallel to two electrode centers lines.Under this kind structure, the weighting function W of each point
yIt is a constant.Like this, satisfy magnetic induction density and weighting function is a constant at the product of any point for uniform magnetic field, and then the board-like interelectrode induction electromotive force of rectangular duct is directly proportional with the flow velocity mean value of section, and irrelevant with the velocity distribution in the section.But in this structure, because electrode is positioned at the inwall of measuring tube and directly contacts with the institute fluid measured, the burn into that electrode is subjected to liquid easily pollutes, even also may cause problems such as leaking and produce the slurry flow moving noise.
By above analysis as can be known, under the excitation of uniform magnetic field, the electromagnetic flowmeter of circular tube structure can be introduced measuring error at the asymmetric flow velocity of measurement; Weight magnetic field can reduce the dependence of the electromagnetic flowmeter convection of circular tube structure, yet desirable weight magnetic field does not exist, and still there is error in circular tube structure under the weight magnetic field excitation; Under the excitation of uniform magnetic field, the inwall that the plate-shape metal electrode is positioned at measuring tube directly with the contacted rectangle measuring tube of the liquid of surveying structure do not rely on velocity flow profile, still, electrode is polluted and corrosion etc. easily.
Summary of the invention
At the defective that exists in the above-mentioned prior art, patent of the present invention problem to be solved provides a kind of under the uniform magnetic field condition, can accomplish to measure the problems such as influence that output is not influenced by velocity flow profile and avoided burn into pollution, leakage and the slurry flow bulk noise of electrode.
A kind of capacitance-type electromagnetic flow transducer with rectangular cross section structure provided by the invention is by the following technical solutions:
The capacitance-type electromagnetic flow transducer that this has rectangular cross section structure comprises measuring tube, electrode, guarded electrode and field coil, it is characterized in that: described measuring tube 1 is rectangular cross section structure; Described electrode is made up of left electrode 2A and right electrode 2B, left electrode 2A and right electrode 2B symmetry attached to measuring tube 1 about the outside; Described guarded electrode is made up of left guarded electrode 3A and right guarded electrode 3B, and left guarded electrode 3A is positioned at the left electrode 2A outside, and right guarded electrode 3B is positioned at the right electrode 2B outside; Described field coil is made up of last field coil 4A and following field coil 4B
Wherein, described measuring tube 1 is a rectangular cross section structure, and its manufacturing materials adopts insulating material, and detected fluid flows through in measuring tube.
Wherein, described electrode is a rectangular metal sheet, form by left electrode 2A and right electrode 2B, a left side electrode 2A and right electrode 2B symmetry attached to measuring tube 1 about the outside, directly do not contact with detected fluid, electrode height equates that with the inside wall height h of rectangle measuring tube the upper and lower end face of electrode is contour with the upper and lower end face of measuring tube inwall respectively.
Wherein, described guarded electrode is made up of left guarded electrode 3A and right guarded electrode 3B, left side guarded electrode 3A is positioned at the left electrode 2A outside, right guarded electrode 3B is positioned at the right electrode 2B outside, and guarded electrode is with electrodes surrounding portion within it, realization is to the shielding of electrode, and the guarded electrode center has an aperture to be used for connection lead on the extraction electrode.
Wherein, described field coil is made up of last field coil 4A and following field coil 4B, lay respectively at the both sides up and down of measuring tube, and by the series connection mode link together, under the exciting current that field circuit 5 provides, produce the uniform magnetic field of working, the line perpendicular quadrature of its magnetic direction and two electrode centers with frequently.
Description of drawings
Fig. 1 be the electromagnetic flow transducer structure that adopts of patent of the present invention and with the converter wiring schematic diagram;
Fig. 2 is that the electrode and the guarded electrode of patent of the present invention is provided with synoptic diagram.
Embodiment
Below in conjunction with accompanying drawing patent working example of the present invention is described in further detail.
As Fig. 1 be the electromagnetic flow transducer structure and with the converter wiring schematic diagram, measuring tube 1 adopts rectangular cross section structure, its manufacturing materials adopts insulating material, detected fluid flows through in measuring tube; Field coil is made up of last field coil 4A and following field coil 4B, lay respectively at the both sides up and down of measuring tube, and by the series connection mode link together, under the exciting current that field circuit 5 provides, produce the uniform magnetic field of working, the line perpendicular quadrature of its magnetic direction and two electrode centers with frequently; Electrode is a rectangular metal sheet, form by left electrode 2A and right electrode 2B, a left side electrode 2A and right electrode 2B symmetry attached to measuring tube 1 about the outside, directly do not contact with detected fluid, electrode height equates that with the inside wall height h of rectangle measuring tube the upper and lower end face of electrode is contour with the upper and lower end face of measuring tube inwall respectively; Guarded electrode is made up of left guarded electrode 3A and right guarded electrode 3B, left side guarded electrode 3A is positioned at the left electrode 2A outside, right guarded electrode 3B is positioned at the right electrode 2B outside, left side guarded electrode 3A links to each other with output terminal with the input end of prime amplifier 8A by the shielding line of being made up of screen layer 7A and lead 6A respectively with left electrode 2A, right guarded electrode 3B links to each other with output terminal with the input end of prime amplifier 8B by the shielding line of being made up of screen layer 7B and lead 6B respectively with right electrode 2B, prime amplifier 8A, 8B all adopts the voltage follower form, thereby form the equipotential shielding, prevent of the decay of signal wire distributed capacitance signal voltage; The signal of prime amplifier 8A, 8B output is sent into signal processing module 10 behind differential amplifier 9, calculate the mean flow rate of tube fluid through respective handling.
As Fig. 2 is that electrode and guarded electrode are provided with synoptic diagram.Electrode 2B is positioned at the outside of measuring tube 1, and guarded electrode 3B is enclosed in its inside with electrode 2B, and electrode is shielded fully, and guarded electrode 3B center has an aperture to be used for line lead on the extraction electrode.
A left side electrode 2A and right electrode 2B all are positioned at the outside of measuring tube, do not contact with survey liquid, thereby have avoided the problem of burn into pollution, leakage and the slurry flow bulk noise of electrode.
More than to the description of the present invention and embodiment thereof, be not limited thereto, only be one of embodiments of the present invention shown in the accompanying drawing.Under the situation that does not break away from the invention aim,, all belong to protection domain of the present invention without designing and similar structure of this technical scheme or embodiment with creating.
Claims (5)
1. the capacitance-type electromagnetic flow transducer with rectangular cross section structure comprises measuring tube, electrode, guarded electrode and field coil, it is characterized in that: described measuring tube (1) is a rectangular cross section structure; Described electrode is made up of left electrode (2A) and right electrode (2B), and left electrode (2A) and right electrode (2B) symmetry are attached to the outside about measuring tube (1); Described guarded electrode is made up of left guarded electrode (3A) and right guarded electrode (3B), and left guarded electrode (3A) is positioned at left electrode (2A) outside, and right guarded electrode (3B) is positioned at right electrode (2B) outside; Described field coil is made up of last field coil (4A) and following field coil (4B).
2. according to the described a kind of capacitance-type electromagnetic flow transducer with rectangular cross section structure of claim 1, it is characterized in that described measuring tube (1) is a rectangular cross section structure, its manufacturing materials adopts insulating material, and detected fluid flows through in measuring tube.
3. according to the described a kind of capacitance-type electromagnetic flow transducer of claim 1 with rectangular cross section structure, it is characterized in that described electrode is a rectangular metal sheet, form by left electrode (2A) and right electrode (2B), left side electrode (2A) and right electrode (2B) symmetry are attached to the outside about measuring tube (1), directly do not contact with detected fluid, electrode height equates that with the inside wall height (h) of rectangle measuring tube the upper and lower end face of electrode is contour with the upper and lower end face of measuring tube inwall respectively.
4. according to the described a kind of capacitance-type electromagnetic flow transducer of claim 1 with rectangular cross section structure, it is characterized in that described guarded electrode is made up of left guarded electrode (3A) and right guarded electrode (3B), left side guarded electrode (3A) is positioned at left electrode (2A) outside, right guarded electrode (3B) is positioned at right electrode (2B) outside, and guarded electrode is with electrodes surrounding portion within it, realization is to the shielding of electrode, and the guarded electrode center has an aperture to be used for connection lead on the extraction electrode.
5. according to the described a kind of capacitance-type electromagnetic flow transducer of claim 1 with rectangular cross section structure, it is characterized in that described field coil is made up of last field coil (4A) and following field coil (4B), lay respectively at the both sides up and down of measuring tube, and by the series connection mode link together, under the exciting current that field circuit (5) provides, produce the uniform magnetic field of working, the line perpendicular quadrature of its magnetic direction and two electrode centers with frequently.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200910236291A CN101699227A (en) | 2009-11-02 | 2009-11-02 | Capacitance-type electromagnetic flow transducer with rectangular cross section structure |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200910236291A CN101699227A (en) | 2009-11-02 | 2009-11-02 | Capacitance-type electromagnetic flow transducer with rectangular cross section structure |
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| CN101699227A true CN101699227A (en) | 2010-04-28 |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102661764A (en) * | 2012-05-25 | 2012-09-12 | 山东泽谊自控技术有限公司 | Quartz tube electromagnetic flow sensor |
| CN105318919A (en) * | 2014-07-10 | 2016-02-10 | 恩智浦有限公司 | Flow sensor |
| CN108333434A (en) * | 2018-01-31 | 2018-07-27 | 北京航空航天大学 | One kind dividing formula parallel organization capacitor array measuring circuit |
| CN110274642A (en) * | 2018-03-13 | 2019-09-24 | 阿自倍尔株式会社 | Capacitive electromagnetic flow meter |
| CN110542459A (en) * | 2018-05-28 | 2019-12-06 | 深圳研勤达科技有限公司 | Small-aperture capacitive electromagnetic flow sensor |
| CN112146715A (en) * | 2020-08-26 | 2020-12-29 | 沈阳兰申电器有限公司 | Excitation method of electromagnetic flowmeter with magnetic field conforming to weight distribution |
| CN112313481A (en) * | 2018-07-12 | 2021-02-02 | 日立汽车系统株式会社 | Flow sensor |
-
2009
- 2009-11-02 CN CN200910236291A patent/CN101699227A/en active Pending
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102661764A (en) * | 2012-05-25 | 2012-09-12 | 山东泽谊自控技术有限公司 | Quartz tube electromagnetic flow sensor |
| CN105318919A (en) * | 2014-07-10 | 2016-02-10 | 恩智浦有限公司 | Flow sensor |
| CN105318919B (en) * | 2014-07-10 | 2020-02-28 | 恩智浦有限公司 | Flow sensor |
| CN108333434A (en) * | 2018-01-31 | 2018-07-27 | 北京航空航天大学 | One kind dividing formula parallel organization capacitor array measuring circuit |
| CN108333434B (en) * | 2018-01-31 | 2020-08-18 | 北京航空航天大学 | Split-program parallel structure capacitor array measuring circuit |
| CN110274642A (en) * | 2018-03-13 | 2019-09-24 | 阿自倍尔株式会社 | Capacitive electromagnetic flow meter |
| CN110274642B (en) * | 2018-03-13 | 2020-10-30 | 阿自倍尔株式会社 | Capacitance type electromagnetic flowmeter |
| CN110542459A (en) * | 2018-05-28 | 2019-12-06 | 深圳研勤达科技有限公司 | Small-aperture capacitive electromagnetic flow sensor |
| CN112313481A (en) * | 2018-07-12 | 2021-02-02 | 日立汽车系统株式会社 | Flow sensor |
| CN112313481B (en) * | 2018-07-12 | 2024-04-16 | 日立安斯泰莫株式会社 | Flow sensor |
| CN112146715A (en) * | 2020-08-26 | 2020-12-29 | 沈阳兰申电器有限公司 | Excitation method of electromagnetic flowmeter with magnetic field conforming to weight distribution |
| CN112146715B (en) * | 2020-08-26 | 2022-09-06 | 沈阳兰申电器有限公司 | Excitation method of electromagnetic flowmeter with magnetic field conforming to weight distribution |
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Open date: 20100428 |