CN1761858A - System and method in a radar level gauging system - Google Patents

System and method in a radar level gauging system Download PDF

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Publication number
CN1761858A
CN1761858A CN 200480007697 CN200480007697A CN1761858A CN 1761858 A CN1761858 A CN 1761858A CN 200480007697 CN200480007697 CN 200480007697 CN 200480007697 A CN200480007697 A CN 200480007697A CN 1761858 A CN1761858 A CN 1761858A
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China
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product
liquid level
level
value
radar
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CN 200480007697
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CN100356145C (en
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莱纳特·哈格
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Rosemount Tank Radar AB
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Saab Rosemount Tank Radar AB
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Abstract

The present invention relates to the field of radar level gauging systems, in which a level of a surface (12) of a product (16) stored in a container (10) is measured. The gauging system comprises: a radar level gauge (14) arranged above the surface (12) of the product (16) which is arranged to transmit a microwave signal towards the product surface (12) and receive a reflected microwave signal from the product surface(12); 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 value; and a second level gauge (20) arranged closed to the bottom of the container (10) and arranged to determine the product level when the measured value is below the predetermined value.

Description

System and method in the radar level gauging system
Technical field
The present invention relates to radar level gauging system, when particularly relating to a kind of liquid level in container, improve the radar level gauging system and the measuring method of the accuracy of measuring the liquid level that is stored in liquid in containers near container bottom.
Background technology
Radar level gauging is generally to be used for now measuring being stored in container, and as the device of the liquid level of the liquid in the oil tank, it receives then from the microwave signal of liquid surface reflection, thereby can determine liquid level by to liquid level launched microwave signal.Importantly, when liquid level during near the bottom, the user can access reading accurately, and can detection receptacle when become empty.
A problem is that when liquid had low specific inductive capacity, the major part of reflected signal was next from the surface reflection of container bottom rather than liquid especially.This can produce distorted signal, removes the filling liquid level height of on-liquid because by the signal of bottom reflection by Liquid Absorption.When liquid is that this problem will constantly increase when hanging down liquid level at large.
Another problem is the bottom section at container, almost total by-product layer, and water for example, its separation owing to liquid, concentrated etc. produces.And when the specific inductive capacity of secondary product is high relatively, a reflected signal that is better than liquid surface will be sent in the interface of secondary product.
Therefore, the radar level gauging device of previously known just has during near the measurement of container bottom in measuring the container of storage of liquids and has limited to.
Summary of the invention
Therefore, when an object of the present invention is to provide the level that a kind of measurement is stored in the surface of the product in the container is the improved method of sky with liquid level and the detection receptacle of allow measuring near container bottom.
Purpose of the present invention realizes that by using following measuring method the method comprising the steps of: the radar level gauging device by being installed in the product surface top is to product surface launched microwave signal; In described radargrammetry device, receive from the microwave signal of product surface reflection; In computing unit, determine the measured value of product liquid level based on the signal that receives; The relatively measured value of this product liquid level and predefined product fluid value; And when this measured value is lower than the predetermined prod fluid value, use second liquid surface measuring device that is installed in container bottom to determine the product liquid level.
Another object of the present invention provides a kind of improved level gauging system, is used for measuring the liquid level on the surface of the product that is stored in container, when is sky with liquid level and the detection receptacle that allows to measure near container bottom.
This purpose realizes by the level gauging system that provides following being used for to measure to be stored in the liquid level of container product, this system comprises: the radar level gauging device that is installed in the product top, this installs to product surface launched microwave signal, and receives the microwave signal of reflection from product surface; Computing unit is used for determining based on the signal that is received the measured value of the liquid level of product; Be used for the device of measured value and predefined product fluid value of comparative product liquid level; With, being installed in second liquid surface measuring device that approaches container bottom, it is used for measuring the liquid level of product when measured value is lower than preset value.
The other objects and features of the invention are from below in conjunction with becoming obvious the detailed description of accompanying drawing.Yet, should be understood that the accompanying drawing purpose only be to explanation of the present invention and, be not to be used for limiting definition of the present invention, the reference of limitation of the present invention should be made by appended claims.Should be appreciated that more accompanying drawing needn't proportionally draw, unless otherwise indicated, otherwise their purpose only is in this description scheme and the conceptual demonstration of step.
Description of drawings
In institute's drawings attached, the identical identical unit of numeric character indication.
Fig. 1 discloses the synoptic diagram that is installed in according to the container in the radar level gauging system of the present invention.
Fig. 2 has shown the synoptic diagram according to the container of Fig. 1, and wherein, the product liquid level in the container is lower than the product liquid level among Fig. 1.
Fig. 3 is the process flow diagram of the creative method of the present invention of execution when being presented at container for sky.
Fig. 4 is the process flow diagram of the creative method of the present invention carried out when being presented at container and being full of.
Embodiment
With reference to figure 1 and Fig. 2, be often referred to and be shown 10 container and be full of liquid 16, the height of liquid or liquid level are determined with radar level gauge 14.Radar level gauge 14 is preferably installed and is sealed on the container port on container 10 tops and with respect to its sealing.Radar level gauge 14 comprises an antenna 18, and antenna 18 is to liquid surface 12 launched microwaves, and receives the reflected microwave signal from liquid surface 12, thereby the indication of the liquid level of liquid 16 in the container 10 is provided.The radar level gauge 14 that is used for launched microwave and reception reflected microwave signal is known, and only schematically shows at this.
An interface determinator 20 is mounted close to the bottom of container 10.Interface determinator 20 is used to measure the liquid level or the level 24 of secondary product 22, and this liquid level is for example because the separation of liquid 16 or concentrate and raise.Radar measuring device 14 and interface determinator 20 interconnect (not shown).In the time of the reflected signal poor quality that receives when radar level gauge or when the level gaging value of liquid surface 12 reaches predetermined value, for example, when the filling liquid level of liquid is low, it is such that image pattern 2 is represented, installation radar measuring device is used for instructing interface-measuring device to recalibrate and comes work as liquid surface measuring device rather than as interface-measuring device.In this article, and term " measured value " be meant with rice the value of the liquid level that is the unit measurement, that is, and the height of tested liquid level.
Preset value is based on experience, and is stored in the radar level gauge 14.When the filling liquid level of liquid 16 was low, the operator was from interface determinator 20 rather than obtain the information of relevant liquid level from radar level gauge 14.The change of this determinator is sightless to the operator.Perhaps, if the operator needs, can provide the liquid level information that obtains from these two level gauge simultaneously.
Interface determinator 20 is reference point (its value preferably is stored in the interface-measuring device 20) by the specific inductive capacity that uses air, and have how many interface-measuring devices 20 to be immersed in the liquid (value that provides by radar level gauge 20), thereby come the liquid level rather than the interface 24 between secondary product 22 and liquid 16 of calibration measurement liquid surface 12 as the range calibration point by use.
In a preferred embodiment of the invention, container is the oil tank that oil is housed.Oil, particularly crude oil all can comprise some water usually, and these water will separate and accumulate in tank bottom from crude oil.In order to determine that how much water is arranged in the oil tank, a water interface gauge is installed in tank bottom.Water interface gauge in the preferred embodiment of the present invention is a capacitance probe.
Capacitance probe uses a kind of like this relation, i.e. electric capacity change and specific inductive capacity are directly proportional.For example, the example of some specific inductive capacity is air-1, oil-4, ethanol-25, water-80.Capacitance probe is known to those skilled in the art, does not go through in this application.Radar level gauge 14 and capacitance probe 20 preferably communicate by the HART agreement.
Usually, capacitance probe knows that the specific inductive capacity of product is necessary.This can have problems when product is the situation of profit mixing, because can not learn specific inductive capacity from bad measurement data result.But in this application, do not need to know in advance specific inductive capacity.This is that promptly, capacitance probe is calibrated by the range calibration point (detector is immersed in the length in the product) that is provided by radar level gauge, thereby can calculate the specific inductive capacity of liquid at an easy rate because of a kind of like this fact.
In the preferred embodiment of the application, when container 10 when empty in the measuring vessel 10 storage liquid 16 liquid surface 12 step as shown in Figure 3, as follows:
1. radar level gauge 14 is by measuring the liquid level (step 31) of liquid surface 12 from the microwave reflection of liquid surface 12 to liquid plane 12 launched microwaves and reception.
2. measured value X compares (step 32) with the predetermined value Y that is stored in the radar level gauge 14.If measured value X is higher than predetermined value Y, then radar level gauge 14 is equal to or less than predetermined value Y according to the height of step 31 measurement liquid surface 12 up to measured value X.
3. when measured value X is equal to or less than predetermined value Y, radar level gauge 14 instruction capacitance probe 20 calibration measurement liquid surfaces 12 rather than water terminations 24 (step 33).Water interface gauge 20 is by using dielectric constant of air as neutral point (this value preferably is stored in the capacitance probe 20), what and have water termination detectors 20 to be dipped in the liquid (value that provides by radar level gauge 20), thereby calibrate as the range calibration point by use.
4. capacitance probe 20 is measured the liquid level (step 34) of liquid surface 12, that is, the interface of air and liquid, this measuring process is to change the fact that is directly proportional with the specific inductive capacity of liquid 16 by the electric capacity that utilizes detector 20 to realize.
In this preferred embodiment of the application, when container 10 was filled with, as shown in Figure 4, the step of the liquid level of the liquid surface 12 of liquid 16 was as follows in the measuring vessel 10:
1. capacitance probe 20 is measured the liquid level (step 41) of liquid surface 12, that is, the interface of liquid and air, this process is to change the fact that is directly proportional with the specific inductive capacity of liquid 16 by the electric capacity of using detector 20 to realize.
2. measured value X compares (step 42) with the predetermined value Y that is stored in the radar level gauge 14.If measured value X is equal to or less than predetermined value Y, then capacitance probe 20 is according to the liquid level of step 41 measurement liquid surface 12, till measured value X is higher than predetermined value Y.
3. when measured value X is higher than predetermined value Y, radar level gauge 14 instruction capacitance probes 20 calibration measurement water terminations 24, i.e. the interface of water 22 and liquid 16, rather than measure the liquid level (step 43) of liquid surface 12.Capacitance probe 20 is calibrated by the calibration point (neutral point and range calibration point) (these preferably manufactured merchants of point are stored in capacitance probe 20) that use is used for water termination 24 measurements.
4. radar level gauge 14 is by also receiving the liquid level (step 44) of measuring liquid surface 12 from the microwave reflection of liquid surface 12 to liquid surface 12 launched microwaves.
Therefore, though the novel features of being implemented by preferred embodiment of the present invention is shown and describes and points out, but should be understood that, the various forms of omissions of the details of the design shown in those skilled in the art can make under the situation that does not break away from spirit of the present invention and form and their enforcement replace and change.For example, clearly all within the scope of the invention, these combinations have been carried out same function in fact, used with quadrat method and have been obtained same effect in the combination of these key elements and/or method.And, will be appreciated that, among any form disclosed by the invention and the embodiment disclosed structure and/or key element and/or method step can be included in any other open describe or the form of suggestion or embodiment in as the routine of a design.Therefore, the present invention is only limited by appended claim.

Claims (9)

1. a measurement is stored in the method for liquid level on the surface of the product in the container, comprises the steps:
With the radar level gauging device that is installed in product surface top to product surface launched microwave signal;
In described radar level gauging device, receive from the microwave signal of product surface reflection;
In computing unit, determine the measured value of product liquid level based on the signal that receives;
The predetermined value of comparative product liquid level gauging value and product liquid level;
When measured value is less than or equal to predetermined product fluid value, use second tape depth gauge of installing near container bottom to determine the product liquid level.
2. method as claimed in claim 1 further comprises when the product liquid level is higher than the predetermined value of product liquid level, the step of the liquid level by product in the second tape depth gauge measuring vessel and the boundary between the secondary product.
3. method as claimed in claim 1 further comprises the step that the specific inductive capacity that uses product and dielectric constant of air are determined the product liquid level.
4. method as claimed in claim 1 further comprises the step of determining the product liquid level by this capacitance probe that is used to calculate the specific inductive capacity of product around the capacitance probe.
5. method as claimed in claim 4 further comprises the step of calibration capacitance detector, and this step is finished by following:
The specific inductive capacity that utilizes air is as neutral point;
The value of the detector length that is dipped in the product is provided by the radar level gauging device;
Calculate the actual value of specific inductive capacity by capacitance probe; With
The specific inductive capacity that uses described calculating is as the range calibration point corresponding to described length.
6, a kind of measurement is stored in the radar level gauging system of the liquid level on the surface (12) of product (16) in the container (10), comprising:
Be installed in the radar level gauging device (14) of the top, surface (12) of product (16), this radar level gauging device (14) is configured to product surface (12) launched microwave signal, and receives from the microwave signal of product surface (12) reflection;
Determine the computing unit of the measured value of product liquid level according to the signal that is received;
The device that is used for the predetermined value of the measured value of comparative product liquid level and product liquid level;
Near second liquid surface measuring device (20) that install container (10) bottom, it is configured to determine the product liquid level when measured value is less than or equal to product liquid level predetermined value.
7, radar level gauging system as claimed in claim 6, wherein, when the product liquid level was higher than the predetermined value of product liquid level, second liquid surface measuring device (20) was configured to the liquid level of the boundary (24) between middle product (16) of measuring vessel (10) and the secondary product (22).
8, radar level gauging system as claimed in claim 6 wherein, uses the specific inductive capacity of product (16) and the specific inductive capacity of air to determine the product liquid level.
9, radar level gauging system as claimed in claim 7, wherein, second liquid surface measuring device is capacitance probe (20), it is provided for determining the liquid level of product, be configured to the measurement products liquid level and carry out describedly determining by capacitance probe (20) boundary (24) between product (16) and the secondary product (22) from be configured to measuring vessel (10) is calibrated to, wherein, neutral point as the specific inductive capacity of air, and as providing by the radar level gauging device, immerse the range calibration point of specific inductive capacity of calculating of value of the length of product (16) corresponding to detector (20), be applied to described calibration steps.
CNB200480007697XA 2003-03-21 2004-03-05 System and method in a radar level gauging system Expired - Fee Related CN100356145C (en)

Applications Claiming Priority (3)

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US10/393,371 2003-03-21
SE03008190 2003-03-21
SE0300819A SE0300819D0 (en) 2003-03-21 2003-03-21 System and method in a radar level gauging system

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CN1761858A true CN1761858A (en) 2006-04-19
CN100356145C CN100356145C (en) 2007-12-19

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102343969A (en) * 2011-07-20 2012-02-08 中国船舶重工集团公司第七○二研究所 Liquid tank without free liquid level
CN101680796B (en) * 2007-05-31 2012-03-21 罗斯蒙特雷达液位股份公司 Radar level gauging system for use at sea
CN101842669B (en) * 2007-11-13 2012-08-08 罗斯蒙特雷达液位股份公司 System and method for filling level determination
CN102853878A (en) * 2011-06-30 2013-01-02 林德股份公司 Method for determining medium level in medium container
CN101842670B (en) * 2007-09-04 2014-01-29 恩拉夫股份有限公司 Method and device for determining the level l of a liquid within a specified measuring range
CN106052603A (en) * 2016-07-04 2016-10-26 重庆大学 Bridge flexibility monitoring system
CN107101695A (en) * 2016-02-01 2017-08-29 Vega格里沙贝两合公司 The method for determining when measuring thing position using radar sensor and showing optimal material thickness
CN109520593A (en) * 2018-11-27 2019-03-26 青岛大学 A kind of detection method using auto-alarming guide wave radar liquid level gauge
CN109520591A (en) * 2018-12-10 2019-03-26 中国核动力研究设计院 New type resin interface level instrument and resin boundary surface measurement method

Family Cites Families (5)

* 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
SE466519B (en) * 1989-04-10 1992-02-24 Saab Marine Electronics DEVICE FOR Saturation of the level of a fluid present in a container
US5614831A (en) * 1995-02-13 1997-03-25 Saab Marine Electronics Ab Method and apparatus for level gauging using radar in floating roof tanks
AU6756198A (en) * 1996-10-07 1998-06-22 Berwind Corporation Material interface level sensing
SE9803377L (en) * 1998-10-06 2000-03-27 Saab Marine Electronics Device for true level measurement in a tank

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101680796B (en) * 2007-05-31 2012-03-21 罗斯蒙特雷达液位股份公司 Radar level gauging system for use at sea
CN101842670B (en) * 2007-09-04 2014-01-29 恩拉夫股份有限公司 Method and device for determining the level l of a liquid within a specified measuring range
CN101842669B (en) * 2007-11-13 2012-08-08 罗斯蒙特雷达液位股份公司 System and method for filling level determination
CN102853878A (en) * 2011-06-30 2013-01-02 林德股份公司 Method for determining medium level in medium container
CN102343969A (en) * 2011-07-20 2012-02-08 中国船舶重工集团公司第七○二研究所 Liquid tank without free liquid level
CN107101695A (en) * 2016-02-01 2017-08-29 Vega格里沙贝两合公司 The method for determining when measuring thing position using radar sensor and showing optimal material thickness
CN107101695B (en) * 2016-02-01 2020-07-07 Vega格里沙贝两合公司 Measuring device, use of a measuring device and method for reducing electromagnetic radiation of a measuring device
CN106052603A (en) * 2016-07-04 2016-10-26 重庆大学 Bridge flexibility monitoring system
CN109520593A (en) * 2018-11-27 2019-03-26 青岛大学 A kind of detection method using auto-alarming guide wave radar liquid level gauge
CN109520591A (en) * 2018-12-10 2019-03-26 中国核动力研究设计院 New type resin interface level instrument and resin boundary surface measurement method

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SE0300819D0 (en) 2003-03-21

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