CN102980630A - Intelligent digital capacitive liquid level sensor - Google Patents
Intelligent digital capacitive liquid level sensor Download PDFInfo
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- CN102980630A CN102980630A CN2012104867971A CN201210486797A CN102980630A CN 102980630 A CN102980630 A CN 102980630A CN 2012104867971 A CN2012104867971 A CN 2012104867971A CN 201210486797 A CN201210486797 A CN 201210486797A CN 102980630 A CN102980630 A CN 102980630A
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- wiring board
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- board body
- level sensor
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Abstract
The invention discloses an intelligent digital capacitive liquid level sensor which comprises a tube body; a top seat is arranged on the top of the tube body in a matched way; a data acquisition and processing circuit board is arranged in the top seat; a pair of corresponding necks are arranged in the tube body; circuit board bodies are clamped in the necks; one or two copper foils which are independent from each other are coated on the circuit board bodies; insulating materials are coated on the surfaces of the copper foils and are isolated and insulated from the measured liquid; metal sheets which are in parallel with the circuit board bodies are also arranged in the tube body; the metal sheets and the circuit board bodies form a capacitance probe of the sensor; the output end of the capacitance probe is connected with part of the data acquisition and processing circuit board; the data acquisition and processing circuit is packaged in a cavity body of the top seat on the sensor by a sealant; and a vent hole is arranged at a joint between the tube body and the top seat. According to the intelligent digital capacitive liquid level sensor, a digital chip capacitance acquisition technology is adopted to measure the height of the measured liquid, so that the continuous and high-precision measurement and display of the height of fuel are realized.
Description
Technical field
The present invention relates to a kind of liquid level sensor, relate in particular to a kind of intelligent digital capacitive liquid level sensor.
Background technology
Traditional first generation liquid level sensor is the contact resistance oscillating rod type, the fork that float is housed by the variation drive of liquid level moves up and down, change in resistance by contact resistance reaches the height of measuring liquid level, because core component is variable resistor, back and forth do mechanical motion with the liquid level variation, and be directly exposed in the fluid to be measured, use for a long time the variable resistor part easy to wear, reading error is also larger, and also be restricted serviceable life; Second generation liquid level sensor fluctuates to measure liquid height by float at fluid to be measured equally, difference is to adopt magnetic semi-annular jade pendant noncontact principle of induction, when the float of embedded magnet fluctuates along the message tube that tongue tube is housed, tongue tube generation adhesive in the magnetic field induction district, tongue tube outside the magnetic field induction district remains open, and by adhesive, the disconnection variation of tongue tube float position is measured.No matter be that the contact resistance oscillating rod type liquid level sensor of the first generation or second generation magnetic spring tube formula non-contact liquid level sensor all are that the fluid to be measured height is measured in the variation that change in location by float drives the sensor internal resistance value, all there are the defectives such as reading out of true, resolution be low, especially in the automobile instrument indication, current widely used fuel liquid level sensor all can't be in the precise height of the current oil tank fuel of instrument reaction.
Along with improving constantly of industrialized level, detection means to liquid level also constantly proposes new demand, New Generation of Intelligent digital capacitance liquid level sensor adopts digit chip electric capacity acquisition technique, use simultaneously MCU that the digital signal that collects is processed, externally directly exporting to Engine ECU or liquid crystal instrument by can or other serial communication protocols again shows, has high precision and resolution, can on liquid crystal display, monitor the amount of fuel in the fuel tank in real time during specific to the fuel gages of automotive oil tank, show in real time each volume read-out and the practical oil consumption of automobile; Need not the mechanical part float in the level gauging simultaneously, the hidden danger of clamping stagnation occurs when also having avoided float to move up and down.Current, digital instrumentation becomes development trend, and traditional vehicle fuel liquid level sensor more and more can't satisfy the requirement of automotive electronics development, and the research and development application that a new generation can only liquid level sensor seems more urgent.
Summary of the invention
The objective of the invention is in order to remedy the deficiency of prior art, a kind of intelligent digital capacitive liquid level sensor is provided, adopt digit chip electric capacity acquisition technique to come the fluid to be measured height is measured, the defectives such as it is fixing dumb by the issuable catching phenomenon of metering system and the mode signal output of the up and down mechanical motion of mechanical floats formula thoroughly to evade traditional liquid level sensor, and the life-span is not long.
The present invention is achieved through the following technical solutions:
A kind of intelligent digital capacitive liquid level sensor, include cylindrical shell, the cooperation of described cylindrical shell top is equipped with footstock, be provided with the data acquisition processing circuit wiring board in the described footstock, it is characterized in that: the draw-in groove that is provided with a pair of mutual correspondence in the described cylindrical shell, be installed with the wiring board body in the described draw-in groove, be covered with a slice or two separate Copper Foils on the described wiring board body, described copper foil surface is covered with solder resist or other insulating material are used for and the fluid to be measured isolated insulation, also be provided with the sheet metal parallel with the wiring board body in the described cylindrical shell, described sheet metal and wiring board body consist of the capacitance probe of sensor, the output of described capacitance probe and data acquisition processing circuit wiring board partly link together, and the data acquisition processing circuit wiring board is contained in fluid sealant in the cavity of footstock on the sensor, and described cylindrical shell and footstock junction are provided with air hole.
Described sheet metal is positioned at the one or both sides of cylindrical shell wiring board body.
The wiring board body that described wiring board body is strip.
The wiring board body surface of described strip is printed with a slice strip Copper Foil.
The wiring board body surface of described strip is printed with two Copper Foils.
Described two Copper Foils are respectively the strip Copper Foil, and the length of two strip Copper Foils is different, and the length of its short-and-medium strip Copper Foil is known definite value.
Described two Copper Foils be respectively the right-angle triangle Copper Foil, the length of described two right-angle triangle Copper Foils is identical, and the inclined-plane corresponding matching of right-angle triangle Copper Foil, is interspersed on the wiring board body surface of strip.
Described insulating material is solder resist.
Its principle is: when liquid height entered the sensor internal cavity from the sensor base opening part, sensor internal air from then on air hole was discharged; When the sensor internal fluid to be measured flows out from bottom opening, extraneous air also from then on air hole enter sensor internal.
The fundamental measurement principle of capacitive transducer, normally changed by wherein a certain physical quantity, such as the specific inductive capacity r of polar plate area A, material, the variations such as liquid level h of material, thereby cause the variation of capacitance, as long as measure the situation of change that the value of this electric capacity just can calculate the respective physical amount that will measure; In liquid level was measured, changing was liquid level, and the measurement by electric capacity reflects the fluid to be measured height just.
Probe segment only can form potential electrode with the parallel metal sheet of cylindrical metal enclosure interior with the wiring board of solder resist covering copper foil conductor, at wiring board surface coverage solder resist, this is the normal process during wiring board is made, and makes the structure ﹠processes of whole sensor realize very simple; The cylindrical metal enclosure interior is as long as both sides are provided with the draw-in groove that can install and fix wiring board simultaneously, in order to simplify the manufacturing process of cylindrical metal housing, its inner parallel metal sheet with wiring board formation pair of electrodes also can be removed, this moment, wiring board then directly formed pair of electrodes with the cylindrical metal housing, and same realization is to the accurate measurement of liquid level.
Advantage of the present invention is:
1, have the various ways mode signal outputs such as analog voltage signal, pwm, can, usart, can be flexible and changeable according to customer requirement, signal output is precise and stable; Realize the fuel oil height continuously, high-precision measuring and demonstration.
2, adopt digit chip electric capacity acquisition technique to come the fluid to be measured height is measured, the defectives such as it is fixing dumb by the issuable catching phenomenon of metering system and the mode signal output of the up and down mechanical motion of mechanical floats formula thoroughly to evade traditional liquid level sensor, and the life-span is not long.
3, when the fuel tank of measuring is Special fuel tank, can pass through the CAN communication interface, directly sensor be demarcated, sensor internal MCU receives and is stored in inner EEPROM behind the calibrating parameters and gets final product, and demarcates simple.
4, sensor internal can use two pairs of capacitor plates to realize the two-way measurement simultaneously, the sensor internal algorithm routine has the intelligent adaptive function, can in different liquids, automatically carry out algorithm adjustment and adaptive measuring, and need not to demarcate calibration according to different liquids.
Description of drawings
Fig. 1 is confined explosion of the present invention structural representation.
Fig. 2 is that the present invention cooperates rear structural representation.
Fig. 3 is the wiring board body construction synoptic diagram that is printed with a slice strip Copper Foil.
Fig. 4 is the wiring board body construction synoptic diagram that is printed with two strip Copper Foils.
Fig. 5 is the wiring board body construction synoptic diagram that is printed with two right-angle triangle Copper Foils.
Fig. 6 is the axial cut-open view of the present invention.
Fig. 7 is radial cross-section of the present invention.
Embodiment
Referring to accompanying drawing, a kind of intelligent digital capacitive liquid level sensor, include cylindrical shell 1, the cooperation of cylindrical shell 1 top is equipped with footstock 2, be provided with the data acquisition processing circuit wiring board in the footstock 2, be provided with the draw-in groove 3 of a pair of mutual correspondence in the cylindrical shell 1, be installed with wiring board body 4 in the draw-in groove 3, be covered with a slice or two separate Copper Foils 5 on the wiring board body 4, Copper Foil 5 surfaces are covered with the solder resist insulating material and are used for and the fluid to be measured isolated insulation, also be provided with the sheet metal 6 parallel with wiring board body 4 in the cylindrical shell 1, sheet metal 6 and wiring board body 4 consist of the capacitance probe of sensors, the output of capacitance probe and data acquisition processing circuit wiring board partly link together, and the data acquisition processing circuit wiring board is contained in fluid sealant in the cavity of footstock 2 on the sensor, and cylindrical shell 1 and footstock 2 junctions are provided with air hole 7; Sheet metal 6 is positioned at the one or both sides of cylindrical shell 1 wiring board body 4; Wiring board body 4 is the wiring board body of strip.
Copper Foil design concrete scheme on its wiring board body is as follows:
The first scheme: as shown in Figure 3, rectangle wiring board body 4 surfaces are printed with the strip Copper Foil of one fixed width, copper foil surface is covered with teflon or other insulating material, play the effect with the fluid to be measured isolated insulation, as a pole plate of electric capacity, another pole plate is the cylindrical metal enclosure interior sheet metal parallel with the wiring board body to this strip Copper Foil 5-1 in the electric capacity level gauging.When carrying out liquid level when measuring, fluid to be measured enters sensor internal from the sensor base opening part, and liquid level h increases since 0, causes that electric capacity changes between two-plate, and the capacitance of measuring this moment just can be extrapolated the liquid level of material.Liquid level not simultaneously, capacitance is also just different, height h and capacitance formation one-to-one relationship; Measurement by capacitance can embody liquid height.
Alternative plan: the first scheme shown in Figure 3 can only be carried out height for same liquid at one time and measured, if the fluid to be measured composition in the capacitive transducer changes, and DIELECTRIC CONSTANT ε namely
rVariation (water 80, alcohol 25, oil 2 have occured, air 1), then need to re-start sensor for concrete fluid to be measured and demarcate calibration, the sensor of demarcating after calibrating equally also can only be measured the liquid of the same race of demarcating calibration, can't Measurement accuracy to other liquid.In actual applications, the first scheme be because need to carry out calibrate when measuring between different liquids, and same liquid is because the difference of concentration, electric constant ε
rAlso can change, cause the actual use of sensor very inconvenient; For this reason, occurred second and third party's case.As shown in Figure 4, the wiring board body surface is designed with the Copper Foil (copper foil surface is with insulating material) of two one fixed widthes, be respectively Copper Foil 5-2 and Copper Foil 5-2 ＇, the length of Copper Foil 5-2 ＇ is a known definite value l less than Copper Foil 5-2 and Copper Foil 5-2 ＇ length, is designed with thinner wire at the wiring board body simultaneously and links to each other (as shown in the figure) with Copper Foil 5-2 ＇ left end A point place; When the wiring board body was packed the cylindrical metal enclosure interior into, Copper Foil 5-2 and Copper Foil 5-2 ＇ formed two teams' electrode with parallel metal sheet respectively.When carrying out liquid height measuring, the electric capacity acquisition chip is measured the electric capacity that two teams' electrode forms respectively, it is maximum that electric capacity capacitance when liquid height reaches Copper Foil 5-2 ＇ left end A point that Copper Foil 5-2 ＇ and metal polar plate form reaches, if this moment, liquid height increased again, the electric capacity that Copper Foil 5-2 and parallel metal sheet form then continues to increase, and the electric capacity that Copper Foil 5-2 ＇ and metal polar plate form is substantially constant.Sensor internal MCU is according to the known length of Copper Foil 5-2 ＇ and collect capacitance and calculate, and the parameter that result of calculation forms is revised the height that the electric capacity of Copper Foil 5-2 and metal polar plate formation reflects automatically, reaches the intelligent adaptive measurement function.In this scheme, Copper Foil 5-2 and metal polar plate are used for liquid height is measured, the electric capacity that Copper Foil 5-2 ＇ and metal polar plate obtain is mainly used in calculating parameter, the electric capacity that Copper Foil 5-2 and metal polar plate form is revised self-adaptation, reach and in different liquids, measure accurately and reliably and need not calibration.
Third party's case: as shown in Figure 5, be designed with equally Copper Foil 5-3 and Copper Foil 5-3 ＇ on the wiring board body, the surface is covered with insulating material equally.Rear and two pairs of electrodes of metal parallel plate formation in the cylindrical metal housing of packing into.When liquid entered sensor internal, the electric capacity acquisition chip gathered the two-way electric capacity respectively, and wherein one the tunnel is used for measuring liquid height, and another road is used and adaptive calibration; Can reach between different liquids equally and measure accurately.
Claims (8)
1. intelligent digital capacitive liquid level sensor, include cylindrical shell, the cooperation of described cylindrical shell top is equipped with footstock, be provided with the data acquisition processing circuit wiring board in the described footstock, it is characterized in that: the draw-in groove that is provided with a pair of mutual correspondence in the described cylindrical shell, be installed with the wiring board body in the described draw-in groove, be covered with a slice or two separate Copper Foils on the described wiring board body, described copper foil surface is covered with insulating material and is used for and the fluid to be measured isolated insulation, also be provided with the sheet metal parallel with the wiring board body in the described cylindrical shell, described sheet metal and wiring board body consist of the capacitance probe of sensor, the output of described capacitance probe and data acquisition processing circuit wiring board partly link together, and the data acquisition processing circuit wiring board is contained in fluid sealant in the cavity of footstock on the sensor, and described cylindrical shell and footstock junction are provided with air hole.
2. intelligent digital capacitive liquid level sensor according to claim 1, it is characterized in that: described sheet metal is positioned at the one or both sides of cylindrical shell wiring board body.
3. intelligent digital capacitive liquid level sensor according to claim 1 is characterized in that: the wiring board body that described wiring board body is strip.
4. intelligent digital capacitive liquid level sensor according to claim 3, it is characterized in that: the wiring board body surface of described strip is printed with a slice strip Copper Foil.
5. intelligent digital capacitive liquid level sensor according to claim 3, it is characterized in that: the wiring board body surface of described strip is printed with two Copper Foils.
6. intelligent digital capacitive liquid level sensor according to claim 5, it is characterized in that: described two Copper Foils are respectively the strip Copper Foil, and the length of two strip Copper Foils is different, and the length of its short-and-medium strip Copper Foil is known definite value.
7. intelligent digital capacitive liquid level sensor according to claim 5, it is characterized in that: described two Copper Foils be respectively the right-angle triangle Copper Foil, the length of described two right-angle triangle Copper Foils is identical, and the inclined-plane corresponding matching of right-angle triangle Copper Foil is interspersed on the wiring board body surface of strip.
8. intelligent digital capacitive liquid level sensor according to claim 1, it is characterized in that: described insulating material is solder resist.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210486797.1A CN102980630B (en) | 2012-11-26 | 2012-11-26 | A kind of intelligent digital capacitive liquid level sensor |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210486797.1A CN102980630B (en) | 2012-11-26 | 2012-11-26 | A kind of intelligent digital capacitive liquid level sensor |
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| CN102980630A true CN102980630A (en) | 2013-03-20 |
| CN102980630B CN102980630B (en) | 2015-12-23 |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103820956A (en) * | 2014-03-21 | 2014-05-28 | 新杰克缝纫机股份有限公司 | Oil mass detection and alarm system of sewing machine |
| CN107036676A (en) * | 2017-05-19 | 2017-08-11 | 中航工业南航（深圳）测控技术有限公司 | Fuel-quantity transducer, fuel quantity meas urement system and measuring method |
| CN107101694A (en) * | 2017-05-19 | 2017-08-29 | 中航工业南航（深圳）测控技术有限公司 | Fuel-quantity transducer |
| CN107167214A (en) * | 2017-05-19 | 2017-09-15 | 中航工业南航（深圳）测控技术有限公司 | Fuel-quantity transducer |
| CN107270997A (en) * | 2017-05-19 | 2017-10-20 | 中航工业南航（深圳）测控技术有限公司 | Fuel-quantity transducer, fuel quantity meas urement system and aircraft |
| CN107270998A (en) * | 2017-05-19 | 2017-10-20 | 中航工业南航（深圳）测控技术有限公司 | Fuel-quantity transducer and fuel tank |
| US11231309B2 (en) | 2016-05-11 | 2022-01-25 | Siemens Healthcare Diagnostics Inc. | Quick connection for liquid level sense-enabled metering probe |
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| CN201697690U (en) * | 2009-07-31 | 2011-01-05 | 佛山市中协电器有限公司 | Capacitive sensing liquid level sensor |
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| US4888989A (en) * | 1986-02-26 | 1989-12-26 | General Signal Corporation | Level sensor system |
| CN2454777Y (en) * | 2000-08-11 | 2001-10-17 | 西北农林科技大学 | Capacitor type watew-flow slit-content sensor |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103820956A (en) * | 2014-03-21 | 2014-05-28 | 新杰克缝纫机股份有限公司 | Oil mass detection and alarm system of sewing machine |
| US11231309B2 (en) | 2016-05-11 | 2022-01-25 | Siemens Healthcare Diagnostics Inc. | Quick connection for liquid level sense-enabled metering probe |
| CN107036676A (en) * | 2017-05-19 | 2017-08-11 | 中航工业南航（深圳）测控技术有限公司 | Fuel-quantity transducer, fuel quantity meas urement system and measuring method |
| CN107101694A (en) * | 2017-05-19 | 2017-08-29 | 中航工业南航（深圳）测控技术有限公司 | Fuel-quantity transducer |
| CN107167214A (en) * | 2017-05-19 | 2017-09-15 | 中航工业南航（深圳）测控技术有限公司 | Fuel-quantity transducer |
| CN107270997A (en) * | 2017-05-19 | 2017-10-20 | 中航工业南航（深圳）测控技术有限公司 | Fuel-quantity transducer, fuel quantity meas urement system and aircraft |
| CN107270998A (en) * | 2017-05-19 | 2017-10-20 | 中航工业南航（深圳）测控技术有限公司 | Fuel-quantity transducer and fuel tank |
| CN107270998B (en) * | 2017-05-19 | 2019-11-26 | 中航工业南航（深圳）测控技术有限公司 | Fuel-quantity transducer and fuel tank |
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| CN102980630B (en) | 2015-12-23 |
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