CN102607668A - Capacitance sensor - Google Patents
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- CN102607668A CN102607668A CN2012101163149A CN201210116314A CN102607668A CN 102607668 A CN102607668 A CN 102607668A CN 2012101163149 A CN2012101163149 A CN 2012101163149A CN 201210116314 A CN201210116314 A CN 201210116314A CN 102607668 A CN102607668 A CN 102607668A
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Abstract
一种电容传感器，包括：传感器表头、内电极和外电极；所述内电极由多个单独的电极组合而成，所有内电极均为内外径相同，同轴排列，从上至下内电极分别为顶部补偿电极、多段测量电极和底部补偿电极，每段电极之间由绝缘材料做成的连接件进行连接；所述外电极通过螺纹连接套在内电极外部，与内电极同轴安装，为内电极中的各段电极公用；传感器表头与外电极连接。本发明消除了温度、压力以及介质等对液位测量的影响，提高了液位测量的精度；另外还有效地避免漏电现象的出现，保证传感器自身的线性度。
A capacitive sensor, comprising: a sensor head, an internal electrode and an external electrode; the internal electrode is composed of a plurality of individual electrodes, and all internal electrodes have the same internal and external diameters, arranged coaxially, from top to bottom They are the top compensation electrode, the multi-segment measurement electrode and the bottom compensation electrode, and each segment of the electrodes is connected by a connector made of insulating material; the outer electrode is screwed to the outside of the inner electrode and installed coaxially with the inner electrode. It is common to all the electrodes in the inner electrode; the sensor head is connected to the outer electrode. The invention eliminates the influence of temperature, pressure and medium on the liquid level measurement, improves the accuracy of the liquid level measurement; in addition, it can effectively avoid the occurrence of electric leakage and ensure the linearity of the sensor itself.
Description
Technical field
The present invention relates to a kind of capacitive transducer; Particularly the self-compensating capacitive transducer of multisection type band is used for level gauging, in particular for the Aviation Fuel oil-level measurement; Can effectively eliminate the influence that measurement brings to liquid level of temperature, pressure and media variations, realize the high-acruracy survey of liquid level.
Background technology
Liquid level is one of crucial industrial physical quantity.Especially, fuel level is one of basis and most important physical quantity in the fuel measuring system.Effective utilization of fuel quantity measurement and flight safety and the energy has substantial connection.The fuel quantity measurement is meant the measurement of fuel oil quality, at first obtains fuel level through fuel level sensor, through calculating the fuel oil volume, in conjunction with fuel density, calculates fuel oil quality again.The fuel level sender of domestic main use at present is a capacitive transducer.Yet the factors such as defective of the complicacy of flight environment of vehicle, the variation of flight attitude and sensor self structure have all greatly influenced the measuring accuracy of fuel level.
Capacitive transducer commonly used mainly is made up of inside and outside two potential electrode of mutual insulating.If ignore the electric leakage between the internal and external electrode, can level value H be written as the function of sensor capacitance value C according to structural parameters, expression formula is:
H＝f(d，D，ε
0，ε
r)C-g(ε
r，h)
Wherein d, D are respectively the diameters of sensor internal and external electrode, ε
0, ε
rBe respectively the relative dielectric constant of dielectric constant of air, fluid to be measured, h is the sensor total length.F (d, D, ε
0, ε
r), g (ε
r, be h) about d, D, ε
0, ε
r, h nonlinear function.When the specific inductive capacity of air, fluid to be measured does not all change, f (d, D, ε
0, ε
r), g (ε
r, h) be normal value, so be linear relationship between level value and the sensor capacitance value.
There is following problem in above-mentioned existing capacitive transducer: at first, the specific inductive capacity of air and fluid to be measured can change along with the variation of temperature, pressure etc., so f (d, D, ε
0, ε
r), g (ε
r, h) can be thereupon change, and because function non-linear, it changes complicated, makes between level value and the capacitance it is nonlinear relationship, calibrate for the demarcation of sensor and brought difficulty.Secondly, variety classes fluid to be measured quality discrepancy is bigger, and specific inductive capacity is also inequality, has further strengthened the difficulty of transducer calibration calibration.At last, when the electrode of capacitive transducer reached certain-length, electric leakage etc. were disturbed bigger, cause that tangible nonlinear relationship is arranged between level value and the capacitance.
Summary of the invention
The present invention is exactly in order effectively to address the above problem, and its objective is in order to eliminate the influence to level gauging such as temperature, pressure and medium, improves the precision of level gauging; Can also effectively avoid the appearance of leaky in addition, guarantee the linearity of sensor self.
Technical solution of the present invention: a kind of capacitive transducer comprises: sensor gauge outfit, interior electrode and external electrode; Electrode is formed by a plurality of independent combination of electrodes in said; External diameter was identical in electrode was in all; Arranged in co-axial alignment, interior from top to bottom electrode is respectively top compensating electrode, multistage potential electrode and bottom compensating electrode, and the web member of being made by insulating material between every segment electrode connects; Electrode was outside in said external electrode was enclosed within through being threaded, with the coaxial installation of interior electrode, for each segment electrode in the interior electrode public; The sensor gauge outfit is connected with external electrode.
There is one deck insulating material the electrode outside in whole; Not only can effectively avoid the corrosion of fluid to be measured to metal electrode; Can also prevent since the internal and external electrode that causes of liquid contamination between the appearance of leakage resistance, thereby improve the measuring accuracy of sensor modulate circuit.
The identical metal circular tube of external diameter in all electrodes are in the electrode in said.
The length of each section potential electrode in the said multistage potential electrode is identical, guarantees that the initial capacitance value of every segment electrode, the full capacitance when immersing fluid to be measured fully all equate, is beneficial to the measurement range design of sensor measuring circuit.
Said bottom compensating electrode is used to compensate the variation of fluid to be measured characteristic, when measuring, is immersed in the fluid to be measured fully; Said top compensating electrode is used for compensation temperature, pressure changes the air characteristics that causes and changes, and when measuring, is exposed in the air fully.When carrying out level gauging, the capacitance of compensating electrode is only relevant with fluid to be measured, dielectric constant of air, and is irrelevant with liquid level, the compensation of the change in dielectric constant that realizes above-mentioned factor is caused.
Said bottom compensating electrode is identical with effective measurement length of top compensating electrode, all less than the length of potential electrode.Since the compensating electrode of sensor top compensating electrode, bottom all with the coaxial installation of potential electrode, and it must satisfy before said installation site and could realize compensating action, so the length of compensating electrode will influence the level gauging scope.So the length of compensating electrode all is shorter than potential electrode length, guarantee the continuous coverage scope of liquid level.
Said dispatch from foreign news agency is metal circular tube very.
Said potential electrode is 6 sections.Be no more than at transducer range under the situation of 1m, 6 sections is comparatively suitable selection, is to draw through a large amount of repetition tests, both can give prominence to the advantage of multistage sensor measurement, again can balancing machine processing and metering circuit difficulty of design.
Said web member two ends are external thread, be used for each electrode of interior electrode between be connected.The insulation of two adjacent electrodes of electrode in the middle column part for protrusion of web member is used for, its external diameter equates with interior electrode external diameter.The center of web member is a through hole, for the lead-in wire that connects potential electrode and metering circuit provides the space.The length of the column part of protrusion is less than the maximum error of measuring of sensor in the middle of the said web member; This is because if liquid level is when just in time being in the web member part; Sensor can not obtain the exact value of liquid level; Think that the level value of this moment is in the web member centre position, maximum measuring error is the half the of protrusion column part length in the middle of the web member.If this length less than the maximum error of measuring of sensor, just can not influence the measuring accuracy of liquid level.
The present invention's advantage compared with prior art is:
(1) the present invention adds bottom compensating electrode and top compensating electrode; Through measuring the capacitance of two building-out capacitors; Carry out Liquid level compensator, make between capacitance and the oil level value of sensor it is linear relationship one to one, all irrelevant with air, fluid to be measured specific inductive capacity; Eliminated the influence of temperature, pressure and medium, improved the precision of level gauging level gauging.
(2) the present invention can be through the length of multistage potential electrode and compensating electrode rationally is set, and when temperature, pressure and type of fuel were all constant, every section capacitance and oil level value had more strict linear relationship.This is that edge phenomenons such as electric leakage are not obvious because electrode length is short more, and the parasitic capacitance value between potential electrode and other insulated metal is less, and is less to the interference of metering circuit, guaranteed the linearity of sensor self.
(3) web member made of the insulating material among the present invention not only couples together electrode in each, and has played insulating effect.Web member is simple in structure, not only is beneficial to machining, and does not increase the complexity of sensor construction, guarantees that sensor construction is compact, no-movable part.
(4) length of the present invention through rationally control bottom compensating electrode and top compensating electrode necessarily more among a small circle in, can be in big level gauging scope the self compensation function of realization sensor.When the length of the complete submergence of fluid to be measured bottom compensating electrode and when not reaching the top compensating electrode, sensor just has compensating action, so the length of compensating electrode will influence the oil-level measurement scope.Still can measure in low liquid level or high fluid level condition for the assurance sensor, need the length of the length of control compensation electrode less than potential electrode.
(5) the public external electrode of the present invention has not only been simplified sensor construction, and has simplified the design of metering circuit greatly.
Description of drawings
Fig. 1 is a capacitor sensor structure front view of the present invention;
Fig. 2 is web member front view and left view among the present invention;
Fig. 3 is the main pseudosection and the left view of potential electrode among the present invention;
Fig. 4 is the sectional view that be connected of web member among the present invention with potential electrode;
The synoptic diagram of Fig. 5 during for measuring liquid level of the present invention.
Embodiment
As shown in Figure 1, capacitive transducer of the present invention is respectively sensor gauge outfit 5, external electrode 1,6,6 sections potential electrode 7 of top compensating electrode, bottom compensating electrode 8 from top to bottom.The web member 3 that each electrode is made by insulating material connects, and there is one deck insulating material 4 the electrode outside in whole.The sensor capacitance value will change along with the variation of liquid level between the internal and external electrode.Thereby metering circuit obtains level value through the variable quantity that detects capacitance.
As shown in Figure 2, be the front view and the left view of web member 3.Web member 3 two ends are external thread 31, are used for linking to each other with each electrode of interior electrode.The column part 32 of middle protrusion is used for the insulation of two adjacent electrodes, and its external diameter equates with interior electrode external diameter.For guaranteeing the continuity of oil-level measurement, the length of middle protrusion column part 32 is less than the maximum error of measuring of sensor.The center of web member 3 is a through hole 33, for the lead-in wire that connects metal electrode and metering circuit provides the space.
As shown in Figure 3, be the main pseudosection and the left view of potential electrode 7.Potential electrode 7 is a metal circular tube, and there is internal thread 71 at two ends, is used for fixing with web member.The centre is a through hole 72, for the lead-in wire of connection electrode and metering circuit provides the space.Lead-in wire directly links to each other with potential electrode through welding manner, causes the part of sensor gauge outfit 5 from the through hole of electrode and web member inside.Because sequence of positions and the oil-level measurement of potential electrode have direct relation, therefore according to the order of each electrode of color differentiating that goes between.
Still can measure under low liquid level or high level condition for the assurance sensor, the length of compensating electrode and potential electrode has certain limitation, and length that it is generally acknowledged compensating electrode is less than 1/5 of potential electrode.If potential electrode is 6 sections, this moment, low liquid level immeasurability length, the ratio that can measure length, high liquid level immeasurability length were 1: 30: 1, can satisfy the compensate function of in big liquid level scope, realizing sensor.
Sectional view as shown in Figure 4, as to be connected with potential electrode 7 for web member 3.Web member 3 and potential electrode 7 have guaranteed the rigidity of electrode in the sensor through being threaded.The column part 32 of protrusion insulate two adjacent electrodes in the middle of the web member, and external diameter equates electrode surface smooth and continuous in guaranteeing with the external diameter of potential electrode 7.If the range of sensor is 1m, the length of protrusion column part is 2mm in the middle of the web member, because the discontinuous error of measurement that web member causes is 1mm, and promptly 0.1%, be 0.5% less than the Design of Sensor measuring error, promptly meet the demands.
As shown in Figure 5, the synoptic diagram when carrying out level gauging for capacitive transducer of the present invention.Fluid to be measured 9 is between the sensor internal and external electrode.When measuring, because the specific inductive capacity of fluid to be measured greater than the specific inductive capacity of air, therefore at first can relatively be obtained the approximate location of level value by the size of each section potential electrode capacitance.The embodiment of the invention adopts 6 sections potential electrode.If obtain the size of 6 sections potential electrode capacitances from bottom to up be: C
1=C
2＞C
3＞C
4=C
5=C
6, then can obtain a certain value of level value in the middle of the 3rd section potential electrode from bottom to up, then the expression formula of liquid level H is written as:
H＝3h
0+h
1+2h
2+H
i
H wherein
0, h
1, h
2Be respectively the length of protrusion column part, compensating electrode, potential electrode in the middle of the web member, be known quantity.Need be through the only level value H in the 3rd segment electrode that specifically measures
i
Make ratio
C wherein
iBe this section capacitance, C
EmptyCapacitance when being zero for this segment electrode liquid level, C
R, C
AIt is respectively the capacitance of bottom compensating electrode and top compensating electrode.Through the expression formula of derivation ratio K, the expression formula that can write out liquid level is:
H
i＝K
*C
i-H
0
Wherein
All can get, so just set up this section level value H through measuring
iWith capacitance C
iLinear relationship one to one, relevant with the capacitance of measuring, and all irrelevant with the specific inductive capacity of air, fluid to be measured with various known quantity, so just reached the effect of the change in dielectric constant that compensation temperature, pressure and medium cause.
Metering circuit is the size of each section potential electrode electric capacity at first relatively, confirms the approximate location of level value; According to aforementioned analytic process, a certain section capacitance of focus measurement converts capacitance into level value through processes such as amplification, analog to digital conversion, through data communication level value sent to computing machine or industrial bus more then.
Although above the illustrative embodiment of the present invention is described; So that the technician of present technique neck understands the present invention, but should be clear, the invention is not restricted to the scope of embodiment; To those skilled in the art; As long as various variations appended claim limit and the spirit and scope of the present invention confirmed in, these variations are conspicuous, all utilize innovation and creation that the present invention conceives all at the row of protection.
The present invention does not set forth the known technology that part belongs to those skilled in the art in detail.
Claims (10)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012101163149A CN102607668A (en) | 2012-04-19 | 2012-04-19 | Capacitance sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012101163149A CN102607668A (en) | 2012-04-19 | 2012-04-19 | Capacitance sensor |
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|---|---|
| CN102607668A true CN102607668A (en) | 2012-07-25 |
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ID=46525253
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|---|---|---|---|
| CN2012101163149A Pending CN102607668A (en) | 2012-04-19 | 2012-04-19 | Capacitance sensor |
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Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103590115A (en) * | 2013-08-21 | 2014-02-19 | 西安隆基硅材料股份有限公司 | Double-heater combined electrode structure of single crystal furnace |
| CN103913207A (en) * | 2014-03-24 | 2014-07-09 | 郑州科达自动化工程有限公司 | High-precision variable-scan oil level measurement sensor with matrix capacitor |
| CN104596611A (en) * | 2015-02-06 | 2015-05-06 | 西安易流物联科技有限公司 | Liquid level sensor |
| CN105133876A (en) * | 2015-07-23 | 2015-12-09 | 杨国威 | Novel swimming pool |
| CN106323415A (en) * | 2016-08-18 | 2017-01-11 | 四川泛华航空仪表电器有限公司 | Method for adjusting capacitance value of capacitive fuel quantity sensor |
| CN106768177A (en) * | 2017-03-22 | 2017-05-31 | 潍坊通达仪表有限公司 | Liquid level sensor, sensing system and liquid level measuring method |
| CN107063389A (en) * | 2017-04-23 | 2017-08-18 | 青岛汇赢科技有限公司 | A kind of condenser type profit identification sensor |
| CN107518851A (en) * | 2017-08-02 | 2017-12-29 | 佛山市顺德区美的洗涤电器制造有限公司 | Dish-washing machine and its liquid level detection device and liquid-level detecting method |
| CN108225480A (en) * | 2018-01-16 | 2018-06-29 | 重庆邮电大学 | Non-contact liquid volume measuring method based on linear type capacitive liquid level sensor |
| CN108419445A (en) * | 2016-12-09 | 2018-08-17 | 法国圣戈班玻璃厂 | Window-glass plate with capacitive sensor |
| CN108603782A (en) * | 2015-12-24 | 2018-09-28 | 埃尔特克有限公司 | Horizontal device and method for detecting medium |
| CN109357727A (en) * | 2018-10-31 | 2019-02-19 | 四川泛华航空仪表电器有限公司 | A kind of capacitance-type fuel quantity measuring system with permittivity compensation |
| CN113503938A (en) * | 2021-07-29 | 2021-10-15 | 湖南铱镝艾姆流体科技有限公司 | Capacitance liquid level meter, liquid level measuring method and system and storage medium |
| CN114111965A (en) * | 2021-12-23 | 2022-03-01 | 济南大学 | Liquid level measuring sensor based on interdigital capacitor and liquid level measuring method |
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| CN1276520A (en) * | 1999-06-08 | 2000-12-13 | 赵明旭 | Self-calibrating capacitor-type liquid level gauge |
| CN1888828A (en) * | 2005-06-28 | 2007-01-03 | 肖书记 | Capacity step-by-step detection sensor |
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2012
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1059597A (en) * | 1991-09-20 | 1992-03-18 | 陈汉达 | Level-sensing device |
| CN1093801A (en) * | 1994-01-14 | 1994-10-19 | 张焕勋 | Sectional capacitance formula thing position detecting method and detection rapier thereof |
| CN1179828A (en) * | 1995-03-29 | 1998-04-22 | 戴姆勒－奔驰公司 | Sensor arrangement |
| CN1276520A (en) * | 1999-06-08 | 2000-12-13 | 赵明旭 | Self-calibrating capacitor-type liquid level gauge |
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Cited By (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103590115B (en) * | 2013-08-21 | 2016-05-18 | 银川隆基硅材料有限公司 | Single crystal growing furnace double-heater combined electrode structure |
| CN103590115A (en) * | 2013-08-21 | 2014-02-19 | 西安隆基硅材料股份有限公司 | Double-heater combined electrode structure of single crystal furnace |
| CN103913207B (en) * | 2014-03-24 | 2017-02-22 | 郑州科达自动化工程有限公司 | High-precision variable-scan oil level measurement sensor with matrix capacitor |
| CN103913207A (en) * | 2014-03-24 | 2014-07-09 | 郑州科达自动化工程有限公司 | High-precision variable-scan oil level measurement sensor with matrix capacitor |
| CN104596611A (en) * | 2015-02-06 | 2015-05-06 | 西安易流物联科技有限公司 | Liquid level sensor |
| CN105133876A (en) * | 2015-07-23 | 2015-12-09 | 杨国威 | Novel swimming pool |
| CN108603782A (en) * | 2015-12-24 | 2018-09-28 | 埃尔特克有限公司 | Horizontal device and method for detecting medium |
| CN106323415A (en) * | 2016-08-18 | 2017-01-11 | 四川泛华航空仪表电器有限公司 | Method for adjusting capacitance value of capacitive fuel quantity sensor |
| CN106323415B (en) * | 2016-08-18 | 2023-05-09 | 四川泛华航空仪表电器有限公司 | Capacitance value adjusting method for capacitive oil quantity sensor |
| CN108419445A (en) * | 2016-12-09 | 2018-08-17 | 法国圣戈班玻璃厂 | Window-glass plate with capacitive sensor |
| CN106768177A (en) * | 2017-03-22 | 2017-05-31 | 潍坊通达仪表有限公司 | Liquid level sensor, sensing system and liquid level measuring method |
| CN107063389A (en) * | 2017-04-23 | 2017-08-18 | 青岛汇赢科技有限公司 | A kind of condenser type profit identification sensor |
| CN107518851A (en) * | 2017-08-02 | 2017-12-29 | 佛山市顺德区美的洗涤电器制造有限公司 | Dish-washing machine and its liquid level detection device and liquid-level detecting method |
| CN108225480A (en) * | 2018-01-16 | 2018-06-29 | 重庆邮电大学 | Non-contact liquid volume measuring method based on linear type capacitive liquid level sensor |
| CN109357727A (en) * | 2018-10-31 | 2019-02-19 | 四川泛华航空仪表电器有限公司 | A kind of capacitance-type fuel quantity measuring system with permittivity compensation |
| CN109357727B (en) * | 2018-10-31 | 2020-08-14 | 四川泛华航空仪表电器有限公司 | Capacitance type oil mass measuring system with dielectric constant compensation |
| CN113503938A (en) * | 2021-07-29 | 2021-10-15 | 湖南铱镝艾姆流体科技有限公司 | Capacitance liquid level meter, liquid level measuring method and system and storage medium |
| CN114111965A (en) * | 2021-12-23 | 2022-03-01 | 济南大学 | Liquid level measuring sensor based on interdigital capacitor and liquid level measuring method |
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Application publication date: 20120725 |