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WO2004083791A1 - Systeme et procede d'un systeme indicateur de niveau radar - Google Patents

Systeme et procede d'un systeme indicateur de niveau radar Download PDF

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Publication number
WO2004083791A1
WO2004083791A1 PCT/SE2004/000311 SE2004000311W WO2004083791A1 WO 2004083791 A1 WO2004083791 A1 WO 2004083791A1 SE 2004000311 W SE2004000311 W SE 2004000311W WO 2004083791 A1 WO2004083791 A1 WO 2004083791A1
Authority
WO
WIPO (PCT)
Prior art keywords
product
level
container
value
dielectric constant
Prior art date
Legal status (The legal status 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 status listed.)
Ceased
Application number
PCT/SE2004/000311
Other languages
English (en)
Inventor
Lennart HÄGG
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Rosemount Tank Radar AB
Original Assignee
Saab Rosemount Tank Radar AB
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
Priority claimed from US10/393,371 external-priority patent/US6828930B2/en
Priority claimed from SE0300819A external-priority patent/SE0300819D0/xx
Application filed by Saab Rosemount Tank Radar AB, Saab Marine Electronics AB filed Critical Saab Rosemount Tank Radar AB
Priority to EP04717911A priority Critical patent/EP1606595A1/fr
Publication of WO2004083791A1 publication Critical patent/WO2004083791A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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
    • G01F23/26—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 capacity or inductance of capacitors or inductors arising from the presence of liquid or fluent solid material in the electric or electromagnetic fields
    • G01F23/263—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 capacity or inductance of capacitors or inductors arising from the presence of liquid or fluent solid material in the electric or electromagnetic fields by measuring variations in capacitance of capacitors
    • 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
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F25/00—Testing or calibration of apparatus for measuring volume, volume flow or liquid level or for metering by volume
    • G01F25/20—Testing or calibration of apparatus for measuring volume, volume flow or liquid level or for metering by volume of apparatus for measuring liquid level

Definitions

  • the present invention relates to radar level gauging systems, and particularly to a radar level gauging system providing improved accuracy in gauging the level of a surface of a fluid stored in a container, when the surface is close to the bottom of the container as well as a method for such gauging.
  • Radar level gauges are commonly used today for measuring the level of the surface of a fluid kept in a container, such as a tank, by transmitting a microwave signal to- wards the fluid surface and receiving a reflected microwave signal from the fluid surface, whereby the level of the fluid surface can be determined. It is important for users to achieve accurate readings of the fluid level close to the bottom and also to detect when the container is empty.
  • Another problem is that there almost always is a layer of a by-product, such as water, in the bottom region of the container, which arises due to separation, condensate etc. Also the interface of the by-product will give a stronger reflected signal than the surface of the fluid, when the dielectric constant of the by-product is relatively high.
  • a by-product such as water
  • This object is achieved through a method comprising the steps of: transmitting a microwave signal towards the product surface using a radar level gauge arranged above the product surface; receiving in said radar level gauge a microwave signal reflected from the product surface; determining in a calculation unit a measured value of the product level based upon the received signal; comparing the measured value of the product level with a predetermined product level value; and determining the product level using a second level gauge arranged close to the bottom of the container when the measured value is below the predetermined product level value.
  • Another object of the invention is to provide an improved level gauging system for measuring a level of a surface of a product stored in a container allowing for measuring the fluid level close to the bottom of the container as well as detecting when the container is empty.
  • a level gauging system for measuring a level of a surface of a product stored in a container comprising: a radar level gauge arranged above the surface of the product and arranged to transmit a microwave signal towards the product surface and receive a reflected microwave signal from the product surface; a calculation unit arranged to determine a measured value of the product level based upon the received signal; means for comparing the measured value of the product level with a predetermined product level value; and a second level gauge arranged closed to the bottom of the container and arranged to determine the product level when the measured value is below the predetermined product level value.
  • Fig. 1 discloses a schematic view of a container in which a radar level gauging system according to the present invention is installed;
  • Fig. 2 shows a schematic view of a container according to figure 1 in which the product level in the container is lower than that in figure 1;
  • Fig. 3 is a flowchart showing the inventive method steps performed when the container is emptied
  • Fig. 4 is a flowchart showing the inventive method steps performed when the container is filled up.
  • a container indicated generally at 10 is filled with a fluid 16, the height or level of which is to be determined utilizing a radar level gauge 14.
  • the radar level gauge 14 is preferably mounted on a container port at the top of the container 10 and is sealed relative thereto.
  • the radar level gauge 14 comprises an antenna 18 which transmits microwaves towards the fluid surface 12 and receives reflected microwaves from the fluid surface 12 to provide an indication of the level of the fluid 16 kept in the container 10.
  • the radar level gauge 14 used for transmitting microwaves and receiving the reflected microwaves is well known and is shown only schematically.
  • An interface gauge 20 is arranged close to the bottom of the container 10.
  • the interface gauge 20 is arranged to measure the height or level 24 of a by-product 22 which arise in the container due to e.g. separation from or condensation of the fluid 16 etc.
  • the radar level gauge 14 and the interface gauge 20 are connected to each other (not shown).
  • the radar level gauge is arranged to commend the interface gauge to recalibrate and work as a level gauge instead of an interface gauge, when the radar level gauge receives bad quality of the received microwave signal or when the measured value of the level of the fluid surface 12 reaches a predetermined value, e.g. when the filling level of the fluid is low, shown in figure 2.
  • the expression "the measured value” means a value of the measured fluid level in meters, i.e. the height of the measured fluid level.
  • the predetermined value is based on experience and is stored in the radar level gauge 14.
  • the operator will thus get the fluid level information from the interface gauge 20 instead of the radar level gauge 14, when the filling level of the fluid 16 is low.
  • This change of gauge may be made invisible for the operator. Or, if the operator so requires, level information from both level gauges may be provided.
  • the interface gauge 20 calibrates into measuring the level of the fluid surface 12 instead of the interface 24 between the by-product 22 and the fluid 16 by using the dielectric constant of air as reference point, which value preferably is stored in the interface gauge 20 and by using how much of the interface gauge 20 that is immersed in the fluid, a value provided by the radar level gauge 20, as span calibration point.
  • the container is a tank filled with oil.
  • Oil especially crude oil, always contains some water which will separate from the oil and end up on the bottom of the tank.
  • a water interface gauge is arranged at the bottom of the tank. The water interface gauge is in the preferred embodiment of the present invention a capacitive probe.
  • Capacitive probes uses a correlation that the capacitive change is directly proportional to the dielectric constant. Examples of some dielectric constants are air-1, oil-4, Ethanol-25 and water-80.
  • the capacitive probes are well-known to the person skilled in the art and are not discussed in detail herein.
  • the radar level gauge 14 and the capacitive probe 20 is preferably communicating via HART- protocol.
  • the capacitive probe calibrates using a span calibration point provided by the radar level gauge (the length of the probe that is immersed in the product), whereby the dielectric constant of the product easily can be calculated.
  • the procedure for measuring the level of the surface 12 of the fluid 16 stored in the container 10 when the container 10 is emptied is as follows:
  • the radar level gauge 14 measures the level of the fluid surface 12
  • step 31 by transmitting microwaves towards and receiving reflected microwaves from the fluid surface 12.
  • the measured value X is compared to a predetermined value Y stored in the radar level gauge 14 (step 32). If the measured value X is higher than the predetermined value Y, then the radar level gauge 14 measures the level of the fluid surface 12 according to step 31 until the measured value X is equal or less than the predetermined value Y.
  • the radar level gauge 14 commends the capacitive probe 20 to calibrate into measuring the level of the fluid surface 12 instead of the water interface 24 (step 33).
  • the water interface gauge 20 calibrates by using the dielectric constant of air as neutral point, which value preferably is stored in the capacitive probe 20 and by using how much of the probe 20 that is immersed in the fluid, a value provided by the radar level gauge
  • the capacitive probe 20 measures the level of the fluid surface 12 (step 34), i.e. the interface between air and fluid, by using the fact that the capacitive change in the probe 20 is directly proportional to the dielectric constant of the fluid 16.
  • the procedure for measuring the level of the surface 12 of the fluid 16 stored in the container 10 when the container 10 is filled up is as follows: 1.
  • the capacitive probe 20 measures the level of the fluid surface 12 (step 41), i.e. the interface between air and fluid, by using the fact that the capacitive change in- the probe 20 is directly proportional to the dielectric constant of the fluid 16.
  • the measured value X is compared to a predetermined value Y stored in the radar level gauge 14 (step 42). If the measured value X is equal or less than the predetermined value Y, then the capacitive probe 20 measures the level of the fluid surface 12 according to step 41 until the measured value X is higher than the predetermined value Y.
  • the radar level gauge 14 commends the capacitive probe 20 to calibrate into measuring the water interface 24, i.e. the interface between water 22 and fluid 16, instead of the level of the fluid surface 12 (step 43).
  • the capacitive probe 20 calibrates by using the calibration points (neutral point and span calibration point) for water interface 24 gauging, which points preferably are stored in the capacitive probe 20 by the manufacturer.
  • the radar level gauge 14 measures the level of the fluid surface 12 (step 44) by transmitting microwaves towards and receiving reflected microwaves from the fluid surface 12.

Landscapes

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

Abstract

La présente invention concerne des systèmes indicateurs de niveaux radar dans qui permettent de mesurer le niveau de la surface (12) d'un produit (16) stocké dans un conteneur (10). Ce système indicateur de niveau comprend un indicateur de niveau radar (14) disposé au-dessus de la surface (12) du produit (16) et destiné à émettre un signal hyperfréquences en direction de la surface de produit (12) et à recevoir un signal hyperfréquences réfléchi par la surface de produit (12); une unité de calcul permettant de déterminer une valeur mesurée du niveau de produit sur la base du signal reçu; un moyen de comparaison de la valeur mesurée du niveau de produit et d'une valeur prédéterminée et un deuxième indicateur de niveau (20) placé à proximité du conteneur (10) et permettant de déterminer le niveau de produit lorsque la valeur mesurée est inférieure à la valeur prédéterminée.
PCT/SE2004/000311 2003-03-21 2004-03-05 Systeme et procede d'un systeme indicateur de niveau radar Ceased WO2004083791A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP04717911A EP1606595A1 (fr) 2003-03-21 2004-03-05 Systeme et procede d'un systeme indicateur de niveau radar

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US10/393,371 US6828930B2 (en) 2003-03-21 2003-03-21 System and method in a radar level gauging system
SE0300819A SE0300819D0 (sv) 2003-03-21 2003-03-21 System and method in a radar level gauging system
US10/393,371 2003-03-21
SE0300819-0 2003-03-21

Publications (1)

Publication Number Publication Date
WO2004083791A1 true WO2004083791A1 (fr) 2004-09-30

Family

ID=33032462

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE2004/000311 Ceased WO2004083791A1 (fr) 2003-03-21 2004-03-05 Systeme et procede d'un systeme indicateur de niveau radar

Country Status (2)

Country Link
EP (1) EP1606595A1 (fr)
WO (1) WO2004083791A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1906158A1 (fr) * 2006-09-07 2008-04-02 Rosemount Tank Radar AB Mesure de niveau par de radar
WO2009077434A1 (fr) * 2007-12-18 2009-06-25 Endress+Hauser Gmbh+Co.Kg Procédé de mesure du niveau de remplissage
CN112525295A (zh) * 2020-11-03 2021-03-19 福建福清核电有限公司 一种导波雷达液位计稳定的温度补偿测量方法

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2298770C1 (ru) * 2006-03-27 2007-05-10 Общество с ограниченной ответственностью Предприятие "Контакт-1" Стенд регулировки и поверки радиолокационных уровнемеров
CN108859741B (zh) * 2018-03-15 2020-07-24 北汽福田汽车股份有限公司 燃油传感器、燃油告警的触发方法及燃油汽车

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1174395A (en) * 1966-04-25 1969-12-17 Fielden Electronics Ltd Improvements in or relating to Level Indicators
US5070730A (en) * 1989-04-10 1991-12-10 Saab Marine Electronics Aktiebolag Device for level gauging with microwaves
US5614831A (en) * 1995-02-13 1997-03-25 Saab Marine Electronics Ab Method and apparatus for level gauging using radar in floating roof tanks
SE512510C2 (sv) * 1998-10-06 2000-03-27 Saab Marine Electronics Anordning för sann nivåmätning i en tank

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1174395A (en) * 1966-04-25 1969-12-17 Fielden Electronics Ltd Improvements in or relating to Level Indicators
US5070730A (en) * 1989-04-10 1991-12-10 Saab Marine Electronics Aktiebolag Device for level gauging with microwaves
US5614831A (en) * 1995-02-13 1997-03-25 Saab Marine Electronics Ab Method and apparatus for level gauging using radar in floating roof tanks
SE512510C2 (sv) * 1998-10-06 2000-03-27 Saab Marine Electronics Anordning för sann nivåmätning i en tank

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1906158A1 (fr) * 2006-09-07 2008-04-02 Rosemount Tank Radar AB Mesure de niveau par de radar
WO2009077434A1 (fr) * 2007-12-18 2009-06-25 Endress+Hauser Gmbh+Co.Kg Procédé de mesure du niveau de remplissage
US8567243B2 (en) 2007-12-18 2013-10-29 Endress + Hauser Gmbh + Co. Kg Method for fill level measurement
CN112525295A (zh) * 2020-11-03 2021-03-19 福建福清核电有限公司 一种导波雷达液位计稳定的温度补偿测量方法

Also Published As

Publication number Publication date
EP1606595A1 (fr) 2005-12-21

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