WO2011132200A2 - Dispositif de détection de niveau - Google Patents

Dispositif de détection de niveau Download PDF

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Publication number
WO2011132200A2
WO2011132200A2 PCT/IN2011/000255 IN2011000255W WO2011132200A2 WO 2011132200 A2 WO2011132200 A2 WO 2011132200A2 IN 2011000255 W IN2011000255 W IN 2011000255W WO 2011132200 A2 WO2011132200 A2 WO 2011132200A2
Authority
WO
WIPO (PCT)
Prior art keywords
solution
level
adblue
resistance
range
Prior art date
Application number
PCT/IN2011/000255
Other languages
English (en)
Other versions
WO2011132200A3 (fr
Inventor
Prethiviraj Balaji
Rajendran Rajmohan
Frank Gottwald
Original Assignee
Robert Bosch Engineering And Business Solutions Limited
Robert Bosch Gmbh
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Robert Bosch Engineering And Business Solutions Limited, Robert Bosch Gmbh filed Critical Robert Bosch Engineering And Business Solutions Limited
Publication of WO2011132200A2 publication Critical patent/WO2011132200A2/fr
Publication of WO2011132200A3 publication Critical patent/WO2011132200A3/fr

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
    • G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
    • G01F23/24—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of resistance of resistors due to contact with conductor fluid
    • G01F23/241—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of resistance of resistors due to contact with conductor fluid for discrete levels
    • G01F23/243—Schematic arrangements of probes combined with measuring circuits
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
    • G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
    • G01F23/24—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of resistance of resistors due to contact with conductor fluid
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
    • G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
    • G01F23/24—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of resistance of resistors due to contact with conductor fluid
    • G01F23/241—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of resistance of resistors due to contact with conductor fluid for discrete levels

Definitions

  • the invention relates to a device to sense level of a fluid in a tank.
  • EP-A-0962751 discloses fluid level sensors comprising resistive film elements disposed in a . container.
  • the conductive fluid in the container provides a relatively low resistance, or short circuit, path between the resistive elements, thus forming a series connection.
  • the resistance of the resistive elements varies continuously in proportion to the changing fluid level in the container. A corresponding change in a voltage output measured across the series resistive elements is indicative of the fluid level in the container
  • the invention proposes a device and a method to measure the level of a fluid in a tank, especially for a fluid whose resistance varies over a period of time.
  • the invention uses a simple resistor network and a table containing a set of range of values for comparing the measured resistance with, each range indicating a specific level of the fluid.
  • FIG. 1 Shows the schematic of the invention
  • FIG. 2 Shows the schematic of another embodiment of the invention.
  • Figure 3 Shows a detailed setup of the embodiment of figure 2.
  • Shown in fig. 1 is a device 10 used to sense the level of the liquid 12 in the tank 14.
  • the liquid 12 can be any kind of liquid, which is conductive or partially conductive, but the invention particularly describes the application for an AdBlue® solution.
  • the AdBlue® is a 32.5 % aqueous urea solution which is used to inject into the exhaust channel of a vehicle to reduce harmful gases.
  • the property of the AdBlue® solution is such that the specific resistance of the AdBlue® solution changes over a period of time.
  • the specific resistance of the AdBlue® solution is known to vary by a factor of 40 over a period of time.
  • the device 10 shown in fig. 1 comprises a conductive element 16, a set of resistors R1 , R2 and R3, and an evaluation unit 8.
  • the evaluation unit 18 further comprises a look up table 20 and a computation means 22.
  • the conductive element 16 has gaps and the gaps are bridged with the resistors R1 , R2 and R3.
  • three resistors R1, R2 and R3 are shown, each resistor used to indicate a specific level i.e. L, M, H respectively, the level L indicating Low level, the level M indicating Middle level and the level H indicating High level. Also there is a level ⁇ ' indicating the tank is empty.
  • a resistance Rs is shown as representing the resistance provided by AdBlue® solution in parallel to each of the resistors R1 , R2 and R3. The resistance Rs is provided by the AdBlue® solution when the corresponding resistors get submerged in the AdBlue® solution.
  • the look up table 20 contains a set of ranges of resistance values against which the read resistance is compared with.
  • the solution 14 is AdBlue® solution.
  • the device 10 may be used more generally in any application where it is desirable to sense or to control, fluid level in a tank.
  • the conductive element and the resistors are preferably disposed vertically in the tank. When the tank is completely empty or near empty, none of the resistors are submerged in the AdBlue® solution. In other conditions where some AdBlue® solution is present in the tank, either one or two or all the three resistors are submerged in the AdBlue® solution depending upon the quantity of the AdBlue® solution in the tank.
  • the AdBlue® solution offers a parallel path of resistance with its specific resistance, for the resistors R1 , R2 and R3 whenever the resistors get submerged in the AdBlue® solution.
  • the values of the resistors selected are as given below:
  • Range 1 Lower limit 16.03 K Ohm; Upper limit 16.88 KOhm.
  • Range 2 Lower limit 10,05 K Ohm; Upper limit 11.74 KOhm.
  • Range 3 Lower limit 0.07 K Ohm; Upper limit 2.65 KOhm. Range 1 , Range 2 and Range 3 are indicative of Low level, Middle level and High level respectively.
  • an input signal or input voltage is applied to the conductive element 16.
  • An output or the resistance across the two contact points of the conductive element is measured.
  • the measured resistance R across the contact points 24 of the conducting element 16 varies with the changing level of the AdBlue® solution in the tank, and is indicative of the level therein, as discussed further below.
  • an input voltage signal V is applied to the conductive element 16.
  • the resistance R is measured across the contact points 24.
  • the device 10 provides three discrete level measurements apart from an empty indication.
  • the discrete levels are explained as examples below:
  • R (R1 II Rs) + (R2) + (R3).
  • the R also varies.
  • a range for resistance value is pre-computed and stored into the look up table 20, taking into account the maximum and minimum specific resistance Of the AdBlue® solution.
  • the range of the resistance values when only R1 submerged into the AdBlue® solution is found to be from 16.03 K Ohm to 16.88 K Ohm.
  • the lower limit 16.03 K Ohm corresponds to a minimum specific resistance of the AdBlue® solution and the upper limit 16.88 K Ohm corresponds to maximum specific resistance of the AdBlue® solution.
  • the computation means 22 determines the combined resistance R. Then the value of R is compared with the ranges stored in the look table. Based on in which range the value of R falls, the level of the AdBlue® solution is determined.
  • the computation means 22 finds from the look up table that the R for the above case falls in Range 1 which is indicative of Low level.
  • Middle level When the level of the AdBlue® solution is such that the two bottom most resistors (R1 and R2) are submerged in the AdBlue® solution, the level is treated as Middle level. When R1 and R2 are submerged in the AdBlue® solution, the combined resistance R measured across the two contact points 24 is given as:
  • R (R1
  • the range of the resistance R value when R1 and R2 are submerged in the AdBlue® solution is found to be between 10.05 K Ohm and 11.74 K Ohm.
  • the lower limit 10.05 K Ohm corresponds to a minimum specific resistance of the AdBlue® solution and the upper limit 11.74 K Ohm corresponds to maximum specific resistance of the AdBlue® solution.
  • the computation means 22 determines the combined resistance R. Then the value of R is compared with the ranges stored in the look table.
  • the R falls within the range of 10.05 K Ohm to 11.74 K Ohm.
  • the computation means 22 finds from the look up table 20 that the R for the above case falls in Range 2 which is indicative of Middle level.
  • R (R1 II Rs) + (R2
  • the resistance R when all the 3 resistors are submerged into the AdBlue® solution is found to be between 0.07K Ohm and 2.65 K Ohm.
  • the lower limit 0.07 K Ohm corresponds to a minimum specific resistance of the AdBlue® solution and the upper limit 2.65 K Ohm corresponding to maximum specific resistance of the AdBlue® solution.
  • the computation means finds from the look up table that the R for the above case falls in Range 3 which is indicative of High level.
  • the level of the AdBlue® solution in the tank is detected unambiguously even when the specific resistance of the AdBlue® solution varies by a large factor, for example a factor of 40 over a period of time.
  • This is achieved by selecting the appropriate values for the resistors R1 to R3 and also using appropriate ranges Range 1 , Range 2 and Range 3 for the resistance values to compare the read resistance R, the ranges being non-overlapping for any two levels.
  • an additional resistor needs to be introduced for every additional level and appropriate range needs to be stored in the look table for each additional level, to compare the read resistance R with.
  • the device can detect more levels of the AdBlue® solution in the tank , thereby increasing the resolution of the measurement.
  • the resistor component of the level sensing device are replaced by metallic elements M.
  • the metallic elements provide the similar functionality as the resistors used in the aforementioned embodiment.
  • the metallic elements used may be in the form of strips, disc, plate and the like.
  • Figure 2 shows the schematic of this embodiment of the invention. As seen from figure 1 the resistances R1 , R2 and R3 which are located in the gaps provided in the conducting element 16 are replaced by the metallic elements.
  • the metallic elements M are chosen such that metallic resistance offers resistance to the flow of current and helps measure the level of the Adblue 12 in the tank 14.
  • the metallic elements M may be clipped, screwed, clinched, clamped, riveted, wrapped around or welded in the gaps provided in the conducting element 16.
  • Figure 3 shows a detailed setup of the metallic elements in accordance with the embodiment of figure 2.
  • the metal used in the manufacture of the metallic elements M is non-corrosive iron sheet.
  • a non-corrosive iron sheet is used so that there is no reaction between the Adblue and the metallic elements M.
  • the conducting elements 16 and the metallic elements M are provided with an injection molded housing 26. At least some part of the metallic elements M which are required to be in contact with the Adblue solution are not a part of the injection molded housing.
  • the injection molded housing can further be provided with an arrangement which allows the housing to be fitted into the tank containing the Adblue solution.
  • the working principle of the level sensing device is similar to that of the embodiment shown in figure 1.
  • the metallic elements M which replace the resistors R1 , R2 and R3 have the same resistance value.
  • all the metallic elements M used are used as a series cascade set of resistances.
  • the total resistance offered by the metallic elements is the sum of the individual resistance offered by each of the metallic elements M.
  • the Adblue is in contact with at least one part of the metallic element located in which is not in the injection molded housing 26, the total resistance value would vary. This variation in the resistance value is compared with the range of the resistance values stored in the look up table. Depending on the range of resistance value obtained from the comparison an indication as to the level of the Adblue in the tank is determined.

Landscapes

  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Fluid Mechanics (AREA)
  • General Physics & Mathematics (AREA)
  • Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)
  • Level Indicators Using A Float (AREA)

Abstract

L'invention concerne un dispositif servant à déterminer le niveau d'une solution dans un réservoir. Ladite solution a la propriété de faire varier la résistance spécifique du dispositif sur une certaine période. Le dispositif comprend un élément conducteur présentant au moins un interstice. Cette interstice est comblé par une résistance R1 de valeur définie. Le dispositif selon l'invention comprend également une table de correspondance contenant un ensemble de gammes de valeurs de résistance, chaque gamme de valeurs de résistance étant représentative d'un niveau spécifique de la solution dans le réservoir, ainsi qu'un moyen de contrôle conçu pour déterminer le niveau de la solution en fonction de la résistance aux points de contact de l'élément conducteur et en fonction de la gamme de valeurs de résistance stockée dans la table de correspondance.
PCT/IN2011/000255 2010-04-19 2011-04-15 Dispositif de détection de niveau WO2011132200A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IN1093/CHE/2010 2010-04-19
IN1093CH2010 2010-04-19

Publications (2)

Publication Number Publication Date
WO2011132200A2 true WO2011132200A2 (fr) 2011-10-27
WO2011132200A3 WO2011132200A3 (fr) 2015-06-11

Family

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Country Status (1)

Country Link
WO (1) WO2011132200A2 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20160334261A1 (en) * 2014-01-21 2016-11-17 Mayo Foundation For Medical Education And Research Medical reservoir level sensor
US10314963B2 (en) 2016-05-16 2019-06-11 Mayo Foundation For Medical Education And Research Medical reservoir level sensor
DE102018210273A1 (de) * 2018-06-25 2020-01-02 Bayerische Motoren Werke Aktiengesellschaft Bestimmung des Vorhandenseins einer leitfähigen Flüssigkeit an einer Mehrzahl von Erfassungsstellen

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0962751A2 (fr) 1998-06-04 1999-12-08 Illinois Tool Works Inc. Mesure résistive du niveau d'un liquide et système de cÔntrole

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL7804852A (nl) * 1977-05-27 1978-11-29 Kernforschungsanlage Juelich Inrichting voor het meten van de niveauhoogte van elek- trisch geleidende vloeistoffen.
GB2288238B (en) * 1994-04-07 1998-07-08 Chromalock Ltd Monitoring device for liquid levels
JP3423166B2 (ja) * 1996-10-18 2003-07-07 ブラザー工業株式会社 インク有無検知装置およびインクジェット記録装置

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0962751A2 (fr) 1998-06-04 1999-12-08 Illinois Tool Works Inc. Mesure résistive du niveau d'un liquide et système de cÔntrole

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20160334261A1 (en) * 2014-01-21 2016-11-17 Mayo Foundation For Medical Education And Research Medical reservoir level sensor
EP3097390A4 (fr) * 2014-01-21 2017-08-09 Mayo Foundation for Medical Education and Research Capteur de niveau de réservoir médical
US10314963B2 (en) 2016-05-16 2019-06-11 Mayo Foundation For Medical Education And Research Medical reservoir level sensor
DE102018210273A1 (de) * 2018-06-25 2020-01-02 Bayerische Motoren Werke Aktiengesellschaft Bestimmung des Vorhandenseins einer leitfähigen Flüssigkeit an einer Mehrzahl von Erfassungsstellen

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Publication number Publication date
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