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WO2003001160A1 - Procede de determination des caracteristiques d'un fond de reservoir - Google Patents

Procede de determination des caracteristiques d'un fond de reservoir Download PDF

Info

Publication number
WO2003001160A1
WO2003001160A1 PCT/SE2002/001227 SE0201227W WO03001160A1 WO 2003001160 A1 WO2003001160 A1 WO 2003001160A1 SE 0201227 W SE0201227 W SE 0201227W WO 03001160 A1 WO03001160 A1 WO 03001160A1
Authority
WO
WIPO (PCT)
Prior art keywords
tank
echo
echo signal
status
empty
Prior art date
Application number
PCT/SE2002/001227
Other languages
English (en)
Inventor
Tomas AKERSTRÖM
Hans Westerlind
Original Assignee
Saab Marine Electronics Ab
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 Saab Marine Electronics Ab filed Critical Saab Marine Electronics Ab
Priority to EP02733761A priority Critical patent/EP1409970A1/fr
Publication of WO2003001160A1 publication Critical patent/WO2003001160A1/fr
Priority to NO20035776A priority patent/NO20035776L/no

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
    • G01F23/28—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 the variations of parameters of electromagnetic or acoustic waves applied directly to the liquid or fluent solid material
    • G01F23/284—Electromagnetic waves

Definitions

  • the invention relates to a method for measuring by means of radar the level of the surface of a medium stored in a tank and in addition, when the level of the surface of the medium in the tank is low or when the tank is empty, for determining, for example, if the tank is completely empty, if the tank is clean, if there is sediment at the base of the tank, and the moisture content of any sediment present.
  • Storage tanks and marine tanks are normally comprised of more or less horizontal metal bases, which in an empty tank provides a considerable amplitude for the echo signal in a radar level measuring device.
  • a radar level measuring device Despite the existence of methods for neutralising the effects of interference from such strong echoes in relation to a normally weak echo from the liquid surface, there remains an unacceptable level of uncertainty for level measuring very close to the base of the tank, which provides an operator with an ambiguous or unclear picture of the actual conditions at the base of the tank.
  • any information comprising precise data about the level of the material near the base of the tank is ignored, since reliable information regarding the conditions at the base of the tank when the tank is considered to be empty is retrieved in another way, for example by probing/sounding with a lead, visual inspection, etc.
  • the invention involves the provision of a method for measuring by means of radar the level of the medium in a tank, in which a medium is stored, in addition to identifying if the tank is empty or not, where the method entails that a radar transmits an electromagnetic signal via an antenna directed down into the tank, that an echo signal from the medium surface is received by the radar, that the level of the medium surface is calculated from a time delay between the transmitted signal and the echo signal, that a number of characteristics of the change in the echo signal amplitude with time during emptying based on historical and/or calculated data are fixed, that a registered curve of the echo signal amplitude during the emptying in question is compared with the fixed characteristics, and that when the tank is essentially empty the status for the empty tank is identified.
  • the method is further characterised by the empty tank status being given according to a rule from a rule framework comprising at least the following fixed characteristic predetermined rules: empty tank, clean tank, tank with sediment, tank with wet sediment, tank with dry sediment.
  • a rule framework comprising at least the following fixed characteristic predetermined rules: empty tank, clean tank, tank with sediment, tank with wet sediment, tank with dry sediment.
  • the invention is preferably employed with storage tanks and marine tanks, where the level of the surface of the contained medium is measured by radar from the tank roof.
  • liquids here including even gases in liquid form, stored in such tanks have a known low dielectric constant.
  • the liquid surface when the surface level is measured by radar with a measuring signal, displays a retro-echo which has significantly lower amplitude than the amplitude of the echo signal that a flat reflecting metal base generates. Not only does the signal reflecting from the liquid surface have low amplitude; it is also the case that a significant portion of the energy of the transmitted measuring signal penetrates the upper layer of liquid. This measuring signal energy can be reflected back to the radar from other metallic objects lower down in the tank.
  • the invention indicates a method for identifying bottom conditions, by means of a set of logical decision-making rules, when all the liquid has been pumped out of a tank, or where it is presumed that all the liquid has been pumped out of the tank.
  • Fig. 1 is a schematic representation of a radar level-measuring device in a tank for determining the surface level of a medium stored in a tank.
  • Fig.2 is a block diagram showing the principle behind the units, which determine the level speed of the surface according to the aspect of the invention.
  • FIG. 1 shows a block diagram of the function of a radar level-measuring device that employs the method in accordance with the aspect of the invention.
  • the principle of a radar level-measuring device is shown in Fig. 1.
  • a tank 1 is used for storing a medium 2.
  • the medium may be a liquid, e.g. oil, refined products, chemicals and gas in liquid form, or be composed of particle material, that is to say a pulverized solid substance.
  • a radar 3 is fixed to the roof 4 of the tank 1, from where a microwave signal is transmitted from the radar via an antenna 5 on the inside of the tank. The transmitted beam is reflected by the medium surface 6 and is intercepted by the antenna 5.
  • Fig. 1 also illustrates the radar lobe 8 and a cleaning device 9 for removing sediments 10, which may be deposited at the base of the tank.
  • the cleaning device 9 is equipped with a spray nozzle 11.
  • a schematic embodiment of the invention is shown in a block and flow diagram in Fig. 2.
  • the radar 3 used for measuring the liquid level in the tank 1 is connected to a computer 12.
  • the computer 12 is in turn connected to a screen 13 for displaying the obtained data to an operator.
  • the computer 12 comprises a number of operation blocks, which are illustrated in more detail in the lower part of the figure.
  • the computer 12 consists of a signal and electronic block 14, which performs signal processing of the signals the radar 3 transmits and receives.
  • Block 15 is a unit for detecting echoes from the liquid surface in the tank 1.
  • An additional block 16 is utilised to treat the multiple echoes.
  • the desired echo signal is chosen and tracked in a selection block 17.
  • the previously mentioned calculating unit 7 determines, using data from the said block, the level of the liquid surface.
  • the measured level obtained is presented on a display in the instrument 18, which can be a screen 13 or other type of display.
  • the procedure illustrated by the description of the flow diagram in Fig. 2 is
  • the data obtained from the selection block 17 is used for storing, in a characteristic block 19, historical signal amplitudes of echo signals particularly at known liquid levels close to the base of the tank.
  • a characteristic block 19 historical signal amplitudes of echo signals particularly at known liquid levels close to the base of the tank.
  • the characteristic of the echo signal amplitude can thus be set for this known status in the tank and be saved in a memory.
  • a rule framework for the implications of each characteristic is stored. Examples of the rules used are presented below.
  • the echo signal amplitude is registered during an ongoing measurement while emptying or tapping the tank.
  • the echo signal amplitude in relation to the time elapsed for emptying and detected liquid level are registered and compared with previously recorded tapping characteristics of the tank, so that the bottom conditions can be identified based on the historical characteristics preserved in the memory.
  • the status is determined in the subsequent block, a status block 21, by interpretation of the relevant characteristic identified for the tank, whereupon the relevant characteristic according to the said rule framework is converted to a status for the tank, which according to the level measuring device is empty.
  • a set of rules are stored in the status block 21, where the rules refer to a number of previously implemented emptying events or cleaning events for the tank or tank type, applicable in the handling of storage tanks and marine tanks, where each case corresponds to a characteristic which is stored in the said memory.
  • a rule is given which denotes the status of the tank or tank type as follows:
  • Typical discharge of carbohydrates and petroleum products from a tank with little or no permanent sediment at the bottom is characterised by echo signal amplitudes from the liquid surface which are strongly influenced by a disturbance from an equally strong or stronger bottom echo when the medium surface level comes close to the base of the tank. Depending on the liquid's degree of transparency for microwaves, this disturbance can arise within a metre from the base of the tank. In this way, the echo signal originating from the tank base will be distinct and with increasing amplitude at a position just before the end of a liquid discharge from a tank, where a relatively low signal amplitude for the echo signal from the surface is present. The echo signal from the tank base must clearly penetrate the liquid awhile until the tank is dry, and the apparent base level must manifest itself by returning a strong and steady echo.
  • carbohydrates e.g. crude oil
  • the signal amplitude of the apparently detected level when the liquid has been pumped out of the tank can be anything from undetectable (fully damped) to very high (as a result of reflection from sediment due to its high water content).
  • iii) Typical discharge of crude oil during the same time as tank cleaning (C. O. W. Crude oil washing). This case includes characteristics from both i) and ii) above, namely an initial situation with damping sediment at the tank base and consequently at the end of cleaning, a situation with a clean base.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Thermal Sciences (AREA)
  • Fluid Mechanics (AREA)
  • General Physics & Mathematics (AREA)
  • Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)

Abstract

La présente invention concerne un procédé permettant la mesure au moyen de radar (3) du niveau de la surface d'un milieu (6) dans un réservoir, dans lequel un milieu (2) est stocké, ainsi que l'identification de l'état du réservoir vide, le procédé comportant: l'émission d'un signal électromagnétique à partir du radar (3) fixé au toit du réservoir (4) via une antenne (5) orientée vers le bas dans le réservoir, de manière à recevoir un signal d'écho en provenance de la surface du milieu (6) par le radar (3), le calcul du niveau de la surface du milieu en fonction d'un retard entre le signal émis et le signal d'écho, l'établissement d'un certain nombre de caractéristiques de modification temporelle dans l'amplitude du signal d'écho lors du vidange du réservoir, en fonction de données historiques et/ou de calcul, la comparaison d'une courbe enregistrée de l'amplitude du signal d'écho lors du vidange du réservoir avec les caractéristiques établies, et l'identification de l'état du réservoir vide lorsque le réservoir est sensiblement vide.
PCT/SE2002/001227 2001-06-21 2002-06-19 Procede de determination des caracteristiques d'un fond de reservoir WO2003001160A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP02733761A EP1409970A1 (fr) 2001-06-21 2002-06-19 Procede de determination des caracteristiques d'un fond de reservoir
NO20035776A NO20035776L (no) 2001-06-21 2003-12-22 Fremgangsmate for a bestemme egenskapene til en tankbunn

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE0102283-9 2001-06-21
SE0102283A SE0102283L (sv) 2001-06-21 2001-06-21 Metod för bestämning av karakteristik för tankbotten

Publications (1)

Publication Number Publication Date
WO2003001160A1 true WO2003001160A1 (fr) 2003-01-03

Family

ID=20284633

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE2002/001227 WO2003001160A1 (fr) 2001-06-21 2002-06-19 Procede de determination des caracteristiques d'un fond de reservoir

Country Status (4)

Country Link
EP (1) EP1409970A1 (fr)
NO (1) NO20035776L (fr)
SE (1) SE0102283L (fr)
WO (1) WO2003001160A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7541969B2 (en) 2007-05-31 2009-06-02 Rosemount Tank Radar Ab Radar level gauging system for use at sea
WO2014198582A1 (fr) * 2013-06-11 2014-12-18 Vega Grieshaber Kg Appareil de mesure de niveau de remplissage pour détermination du taux d'humidité
JP2018132366A (ja) * 2017-02-14 2018-08-23 ムサシノ機器株式会社 高位液面警報装置
CN116989869A (zh) * 2023-09-28 2023-11-03 江苏索利得物联网有限公司 一种基于料仓参数分析的仓顶雷达扫描方法

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108680231A (zh) * 2018-04-11 2018-10-19 中国电建集团成都勘测设计研究院有限公司 可旋转折叠式雷达水位计安装支架结构

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5614911A (en) * 1993-09-21 1997-03-25 Endress + Hauser Gmbh + Co. Radar-based method of level measurement
US5827943A (en) * 1995-10-27 1998-10-27 Endress + Hauser Gmbh + Co. Method for calibration in level measurement
US5948979A (en) * 1997-06-05 1999-09-07 Endress + Hauser Gmbh + Co. Radar-based method of measuring the level of a material in a container

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5614911A (en) * 1993-09-21 1997-03-25 Endress + Hauser Gmbh + Co. Radar-based method of level measurement
US5827943A (en) * 1995-10-27 1998-10-27 Endress + Hauser Gmbh + Co. Method for calibration in level measurement
US5948979A (en) * 1997-06-05 1999-09-07 Endress + Hauser Gmbh + Co. Radar-based method of measuring the level of a material in a container

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7541969B2 (en) 2007-05-31 2009-06-02 Rosemount Tank Radar Ab Radar level gauging system for use at sea
WO2014198582A1 (fr) * 2013-06-11 2014-12-18 Vega Grieshaber Kg Appareil de mesure de niveau de remplissage pour détermination du taux d'humidité
US10072961B2 (en) 2013-06-11 2018-09-11 Vega Grieshaber Kg Level measuring instrument for determining moisture content
JP2018132366A (ja) * 2017-02-14 2018-08-23 ムサシノ機器株式会社 高位液面警報装置
CN116989869A (zh) * 2023-09-28 2023-11-03 江苏索利得物联网有限公司 一种基于料仓参数分析的仓顶雷达扫描方法
CN116989869B (zh) * 2023-09-28 2023-12-19 江苏索利得物联网有限公司 一种基于料仓参数分析的仓顶雷达扫描方法

Also Published As

Publication number Publication date
SE517807C2 (sv) 2002-07-16
SE0102283L (sv) 2002-07-16
EP1409970A1 (fr) 2004-04-21
NO20035776L (no) 2004-02-02
SE0102283D0 (sv) 2001-06-21

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