CN101825487A - Sheltering device for radar type liquid level measuring apparatus - Google Patents
Sheltering device for radar type liquid level measuring apparatus Download PDFInfo
- Publication number
- CN101825487A CN101825487A CN201010167435A CN201010167435A CN101825487A CN 101825487 A CN101825487 A CN 101825487A CN 201010167435 A CN201010167435 A CN 201010167435A CN 201010167435 A CN201010167435 A CN 201010167435A CN 101825487 A CN101825487 A CN 101825487A
- Authority
- CN
- China
- Prior art keywords
- masking device
- base section
- radar
- masking
- jar
- 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.)
- Granted
Links
Images
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
Abstract
On the one hand, the present invention includes a kind of masking device that is used for liquid level radar measurements, comprise the ripple screen that is communicated with liquid fluid.On the other hand, the present invention includes a kind of equipment that is used to measure liquid level, comprise radargrammetry device and waveguide, the radargrammetry device has antenna, is used for sending signal towards the surface of liquid.Described equipment is characterised in that it comprises masking device, described masking device be suitable for being arranged on stablize under the pipe and pot bottom on, wherein, described masking device is communicated with liquid fluid.
Description
The application be submitted on April 11st, 2006, application number is 200680035434.9 (international application no is PCT/NO2006/000134), denomination of invention is divided an application for the patented claim of " sheltering device for radar type liquid level measuring apparatus ".
The present invention relates to be used in storage container, measuring the radar type instrument of liquid volume, particularly be arranged on the radar instruments on the waveguide (stilling well or stable pipe) that extends to container vertically downward.The termination of the short distance above the bottom of container of described waveguide possibility owing to a variety of causes, thus between waveguide and bottom, stay little gap.Liquid surface below waveguide lacks the protection that waveguide provides, thereby is exposed to wave phenomenon from the teeth outwards fully.
Although the present invention will be described according to the storage tank on the sea lift vessel, also can in the container of any kind, implement the present invention, for example land LNG (liquefied natural gas (LNG)) storage tank, petroleum products jar, chemicals jar and liquid nutritional jar.
Especially in regard at sea lift vessel, for example transport the liquid that is in low liquid level in the storage tank on the ship of liquefied natural gas (LNG), known, the radar return that is produced by liquid surface is subjected to the interference of capillary wave and turbulent flow on the one hand, and is subjected to the interference at the echo of the bottom of jar generation on the other hand.It is generally acknowledged that two types interference all should be minimized, so that allow radar level gauge to come measuring liquid level with the required precision that is used for the custody transfer metering on the sea lift vessel.
In radar level gauging (for example US 6184818 is described), use and stablize pipe and to avoid and a jar interior equipment interference, and the surface turbulence that prevents liquid causes the fluctuation of reflected signal.Stable pipe is the pipeline that always extends to a certain distance in top, bottom of jar from the top of jar.Antenna is set in the pipe or is set directly at the top so that pipeline is guided radiation downwards as waveguide of pipe.When and surface liquid lower in liquid level was positioned under the opening of stablizing pipe, such being arranged in the operation was can be not gratifying, because pipeline can not provide the stabilized zone on liquid surface.In addition, at the lower area existence turbulent flow highly of jar, because pumping installations has opening in this zone.
In addition, according to prior art, for fear of because the interference that causes of bottom reflection signals, deflecting plate or device with similar functions, attenuator for example, be set directly at antenna below.The The Application of Technology that is used for these types of the level gauging in the LNG storage tank was described (committee draft of ISO international standard 13689:2001) in 1996.
WO 01/29523 has described a kind of equipment by radar level gauging device mensuration liquid level, and wherein, microwave absorber is placed with the absorption microwave energy in the bottom of jar under the opening of pipeline, thereby prevents the echo from the bottom of jar.Such device is unsuitable for the use in the main application fields of its membrane type jar, in described application, for some designs, all devices must be positioned at jar the bottom at a distance of a certain distance, and can not be located immediately on the described bottom.In addition, this device does not provide the protection that prevents surface turbulence.
The objective of the invention is to, at stable pipe owing near at the bottom of the jar, obtain controlled measuring condition under the situation of any former thereby bottom that can not extend to jar always.The controlled measuring condition of term refers in the context of the present invention, therein because jar measuring condition that the interior caused clutter of other equipment, surface turbulence and bottom reflection is reduced.For vessel tanks, above-mentioned interference source is the fluctuation in the jar that motion caused of the ship that causes of the wave that produced by wind-force and wave, or the change of the trim angle/heeling angle of the ship that is caused by the load/unload of ballast or goods.Also can propagate by tank skin and jar other interior physical constructions from the vibration of machine, and in jar, produce small echo/capillary wave.In the inside of jar, cargo pump not only produces vibration but also produce fluctuation.Particularly in the LNG storage tank, additional interference source is spray pump/stripping pump and unloading pipeline, and for all types of low temperature goods, vaporization will cause interference on the surface.
Needs near measuring condition controlled at the bottom of the jar come from for example LNG membrane type jar, and therein, the barrier film (that is, invar sheet metal film) to some type must have safe distance all the time between lower end of stablizing pipe and diaphragm type pot bottom.Relevant restricted may being: can not directly on the membrane type pot bottom, place or support any structure part, can not be in well-digging on the tank bottom with the placement said apparatus or by in jar, upwards measuring measuring liquid level.In addition, the supporting construction of pipeline and pipeline (tripod or similar structures) may be subjected to thermal shrinkage with respect to tank skin under cryogenic conditions, so at least at low temperatures, lower end and jar at pipeline have significant free beam space at the end, therein, liquid surface and measuring accuracy is descended with the interference of the interference of bottom reflection.
Therefore the purpose of this invention is to provide a kind of device, can near the bottom of jar, realize high-acruracy survey by described device.
The purpose of this invention is to provide a kind of device, described device is convenient to produce and install, and, adopts minimum independent sector and low weight, so carriage or other supporting mechanisms can be frivolous that is.The requirement of the relative positioning of described device below pipeline is not necessarily harsher than the requirement that this jar normal method of construction (being the welding of carriage) is satisfied.
Another object of the present invention provides a kind of device, and described device has the design that prevents to destroy jar film and avoid any possibility that parts rupture during operation, because these parts may be soaked into and destroy cargo pump.
On the one hand, the present invention includes a kind of masking device that is used for the radargrammetry of the low liquid level in the container, it is characterized in that, described masking device comprises that near the ripple the bottom that is positioned at container shields and is communicated with liquid fluid.
On the other hand, the present invention includes a kind of equipment that is used to measure the low liquid level in the container, comprise a kind of radargrammetry device and waveguide, described radargrammetry device has antenna, is used for sending signal towards the surface of liquid.Described equipment is characterised in that it comprises near the masking device the bottom that is positioned at container, and described masking device is communicated with liquid fluid at this place.
Therefore, an aspect of of the present present invention provides a kind of scheme, is used to cover the part of fully big liquid surface to provide best possible condition to produce the radar return of high-quality at described liquid surface.
Aspect second, the present invention also comprises a kind of device, and described device is suitable for making from the interference that radar signal produced of the bottom reflection of jar reduces to minimum.This can realize by various hidden technologies, for example absorber, deflecting plate and diffractive geometries, or the combination of these technology that can expect.
The purpose of these two aspects of the present invention is near the signal fidelities that help the raising of the relevant echo that is produced by liquid surface the bottom of container, thereby also allows radar equipment that the liquid that is in very low liquid level in the storage container is measured accurately.
In one embodiment of the invention, described device is made of the material of single type, fiber mat or comprise the braided material or the similar material of carbon fiber for example, thus satisfy the requirement that makes the liquid level calmness inherently, and fully soft so that barrier film is not constituted danger.This embodiment should not be understood that it is to be under such situation: the high microwave absorbing efficient of the attenuator structure that for example resonates is necessary, and perhaps may to come off and enter the danger within the arrival ship pump be unacceptable to fiber.Therefore can expect that the different designs of described device is applicable to different application and requirement.
In another embodiment, described device is made and/or is covered by radar absorbing material at least in part.
In another embodiment, described device comprises the fastener that is used to be fastened to tripod guidance structure.In the idio-morphosis of this embodiment, described fastener comprises at least one articulation joint, and/or is made by thermal insulation material, and/or comprises extensible part.
In another embodiment of the present invention, described masking device is suitable for making from the interference that radar signal produced of the bottom reflection of jar reduces to minimum.In another embodiment, described masking device comprises blanker, for example attenuator, deflecting plate and diffractive geometries.In the idio-morphosis of the embodiment that in the end mentions, described blanker is set at ripple and shields on last and/or the base section.
In another distortion, the ripple screen is positioned within the main lobe of radar beam.This specific embodiments of the present invention is applicable to the jar of size restrictions, for example Samsung 1442 (internal measurement of 130 * 230 * 180mm).In another distortion, described device is very big with respect to the size of the radiation lobe of radar beam, can ignore with the interaction of ripple screen by this way.
In another embodiment, described ripple screen is suitable for around stablizing pipe so that telescopic setting to be provided.
In one embodiment of the invention, described ripple screen comprises perforation.In another embodiment, described device comprises base section, is fit to make from the interference that radar signal produced of the bottom reflection of jar reduce to minimum.
In another distortion, described base section is rectangle or foursquare.
In another embodiment, described base section comprises the major part of resonance absorber with the radar signal of weakening incident, makes like this to detect little radar return on the position of displacement downwards, thereby increases the significant depth of liquid.
In another embodiment, described base section is equipped with the flaggy of grid pattern, is used to change the impedance of input impedance with coupling LNG.In the distortion of this embodiment, described base section comprises one deck attenuating material, and preferably includes screw, is used for the attenuating material layer is fastened to the backing metal.In another distortion, described one deck attenuating material is positioned under the grid pattern.In another distortion, described metal-backed at least two zones that comprise, described at least two zones are positioned at apart from the different distance of grid pattern (quarter-wave rank) to be located.Described attenuating material has to be made from the faint as far as possible function of the reflection of base section.Provide metal-backed the making on quarter-wave rank in the direction of pipeline, to offset from being reflected in backward of two zones.Described attenuator resonates, and just the thickness of described attenuator is adapted to the wavelength of radar signal, so radar energy is hunted down in attenuator and dissipates.Border between preferred two zones is corresponding to the axis of symmetry of the main lobe of radar beam.
In another embodiment, masking device according to the present invention is shaped as container, and therein, the ripple screen comprises wall of a container, and base section comprises the bottom of container.
In one embodiment of the invention, described masking device is equipped with attenuator within its underpart.
The purpose of described container provides the stabilized zone, described stabilized zone extends to several at least centimeters more than the lower end of stablizing pipe from the bottom of jar, seldom surpass 25 centimetres on the whole, however, still can avoid surface wave and bottom reflection destruction measuring-signal.
In one embodiment of the invention, the wall of described masking device is bored a hole at least in part and is communicated with the fluid of outside liquid to set up.Described perforation will be fit to providing connection low time delay, so the liquid level in the described masking device becomes along with the average liquid level of described device outside under the pumping rate of the highest regulation that is used for equipment less than the maximum deviation of the overall measurement precision of regulation with (significantly).Use for existing LNG, described delay should be generally less than 1-2mm.
Yet another effect of the perforation of described wall is that the interference from the outside will enter in the zone of crested.For this reason, in one embodiment of the invention, the zone of described perforation is minimized and is set on the bottom periphery of masking device to suppress entering of capillary wave, arrive the bottommost of described masking device up to the liquid level of jar, and the zone of described perforation is set up in irregular mode, so that the constructive interference between the various opening is minimized.On the other hand, described perforation also has the effect that the standing wave in the masking device is weakened, and for this reason, in one embodiment of the invention, the zone of described perforation is very big and spread in irregular mode on the whole sidewall of masking device, and/or the zone of described perforation comprises section vertical or that tilt.For the fluid dynamics filter effect that obtains to want enters so that prevent fast-changing interference, and not changing more fast in the inner sustain average level of masking device, in one embodiment of the invention, described perforation is made of a lot of apertures rather than some macropores.Preferably sharp keen (90 degree), the edge in each hole to be increasing hydrodynamic losses, thereby obtain the decay of level fluctuation fast fully.Be appreciated that from detailed description above, design according to masking device of the present invention can be optimised with the compromise proposal between the contradictory factor of three parts to be used for each type of described equipment, and the contradictory factor of described three parts is: the fully connection of liquid level fast; Prevent that fluctuation from entering masking device; Make the fluctuation decay in the masking device.
As mentioned above, in one embodiment, the ripple screen comprises perforation.These perforation will allow the surface of liquid to become fully tranquil, thereby obtain stable measurement, yet, provide with the rapid of surrounding liquid to be communicated with to obtain abundant low time constant and the delay on the reading during the pumping operation the most fast in bottom section.In an embodiment of the present invention, this is particularly important when being closed at the ripple screen.
Masking device according to the present invention comprises the ripple screen of preferred perforation, preferably include radar transparent material or cover radar absorbing material on the inner face, have physical size and shape (blanking function) that the radar signal that makes minimum incident is reflected back to radar receiver.This has realized that also described liquid surface standing wave comprises the capillary wave in the described device to effectively the avoiding and suppress of the liquid surface standing wave of resonance.
In one embodiment of the invention, the ripple screen is narrow, so that it surrounds stable pipe and allows to slide as sleeve with respect to stablizing pipe when shrinking.In another embodiment that the present invention uses, can be hindered by thermal effect or during any other misalignment of the movable part of structure dangerous, the diameter of ripple screen just is increased so that the space is under any circumstance all arranged between pipeline and masking device as described sleeve.In one embodiment of the invention, the ripple screen has the shape of tubulose, and in another embodiment, described ripple screen does not form the geometry of sealing and comprises crooked wall.
In one embodiment of the invention, masking device comprises base section.Design described base section so that during installation, if (double error) do not destroy barrier film perhaps will occur any damage of system during operation the time.Described masking device has minimum sharpened edge at the bottom side, and in one embodiment, described masking device be equipped with teflon for example nonmetallic materials apart from keeper, thereby make the corrosion of jar film or the danger of wearing and tearing reduce to minimum.Minor increment on the described jar film decides by concrete application, as the safe distance of being used by jar deviser and shipyard and by compromise between the requirement of minimum metering liquid level of shipowner's regulation.Usually, the safe distance that is used for abundant plate membrane jar is 3-5mm.
The base section of masking device can comprise absorbing material, and described absorbing material is used as attenuator in essence, and covers the entire area of described bottom in preferred design.Yet, described design can be adopted different forms, wherein, described absorbing material can be distributed on the differing heights of base plane of whole masking device, thereby constitute grid (or diffraction) structure, described cell structure is well suited for the residual echo that produces at described base section is transferred to outside the sensing range of radar.
Reduce to minimum in order to make in the possibility of the vaporization of masking device inside, in one embodiment, described masking device is had the material of low specific heat to be made, so the temperature in the masking device all equals environment temperature at any time.
Described material also satisfies other environmental requirement, for example to the applicability of temperature range, aggressive chemicals or corrosive liquids, and in one embodiment, described device by on Support bracket, using insulated part with supporting construction basically heat isolate, so heat that shifts by tripod structure from the top of jar and stable pipe are prevented from heating the liquid in the masking device.The isolated part of masking device and carriage can both be used for the LNG storage tank for example made by plastic material, and in described plastic material, teflon may be most commonly used to cryogenic applications.
Reduce to minimum in order to make the possibility that produces capillary wave in the masking device, in one embodiment of the invention, the supporter of described masking device comprises the device that is used for vibration damping, and it is mechanically isolated the miscellaneous part of described masking device and pump or ship by the caused vibration of jar structure.
Vibration damper is for example made by metal spring or block rubber, but at low temperatures, most of materials become fragile or discharge its flexibility, and under these circumstances, only a few materials is used, for example mylar and similarly plastics.
In some applications, permission connects by welding, bolt or by the use clamp bracket described masking device directly is installed to pot bottom.In one embodiment of the invention, described masking device comprises thin polyfluortetraethylene plate or the analog that is between described device and jar film, thereby allows to slide relatively freely, in case described device and jar film be can't help the material that thermal constant equates and made.
In being suitable for the embodiment that described masking device can not be directly installed on the situation on the pot bottom, described masking device comprises fastener, described fastener is the form of arm for example or carriage, described arm or carriage are connected in the supporting construction that is arranged on the bottom, perhaps are installed in fixing vertical distance with respect to the bottom of jar with other any methods.In a preferred embodiment, this supporting construction is the guide structure that is used for tripod, also is used to support stripping pump, and described stripping pump is used for emptying at last of jar.Therefore, in the liquid level of minimum measurement with between fixing relative and selectable vertical range is arranged all the time by pumping minimum liquid level in one's power.
In one embodiment of the invention, masking device comprises the fastener that is adapted to be mounted within on the structure part, and described structure part is shunk with respect to the upright position of pot bottom.This realizes by the structure arm partly that is connected in described masking device and is concerned about, described arm is automatically adjusted with the effect that is suitable for shrinking, for example by the bimetallic element in the use structure or by the ACTIVE CONTROL in the upright position of described masking device.
In one embodiment, masking device is made and/or is covered by radar absorbing material at least in part, and described radar absorbing material is suitably woven or make the ideal effect that the fluid dynamics standing wave is weakened to provide in masking device.Suitable material for example is the material of Kevlar (Kevlar) or other carbon fibers.
As previously mentioned, in one embodiment, masking device can be basically made by fiber mat or the braided material or the similar material that comprise carbon fibre material.This embodiment combines the required effect of the perforation of wall, thereby allows the fluid connection by described wall, to the decay from microwave outside and that produce in the vibration damping of the fluid dynamics fluctuation of inside and the absorption by carbon and by the scattering of irregular surface.Such flexible apparatus also can satisfy the requirement of avoiding the infringement of the thin jar barrier film of bottom inherently.In order to improve the rigidity of described masking device, in one embodiment of the invention, described fiber mat by sprayed with adhesive or plastic material with wetting and assemble described fiber.Also can be described masking device equipment support ring.
In one embodiment of the invention, irregular and asymmetric in surface level by making masking device, utilize the wedge shape of sidewall or ripple that the interior ripple pattern within the masking device is decomposed.Because therefore very strong half wave resonances preferably avoids simple, regular geometry.Preferred global shape is the polygon of odd number side, also preferably has the unequal length of side.
Can expect, interference and the turbulent flow that capillary wave produces can be reduced to acceptable level so that quite flat surface to be provided with the radar return that is used to produce high-quality by using the part of covering (comprising the ripple screen) fully big liquid surface according to masking device of the present invention.Described ripple screen can take different shape and design so that the effective damping force to capillary wave and turbulent flow to be provided, and does not destroy the quality from the radar return of liquid.For the feature of described ripple screen, can use various hidden technologies, for example absorber, deflecting plate and diffractive geometries, or the combination of these technology that can expect.
On the other hand, the available a lot of methods of the interference that radar signal produced from the bottom reflection of jar minimize.Selection is to use a kind of material for described masking device or the part (for example base section) that is at least described masking device, and described absorbed radar energy is reflected into degree from the detectable echo of the bottom of container to reach tolerable sub-fraction energy.Another selection is to use the sheet metal of inclination, and the major part that the sheet metal of described inclination makes radar signal deflected on one side before the bottom that arrives container, almost can not be by detections of radar from the echoed signal of the bottom of container thereby also make.The 3rd method relates to the grid or the arrangement of geometric configuration and pattern, is used for making the major part of backward energy to be diffracted into outside the sensing range of radar.Those skilled in the art can easily expect, may form a variety of devices that are very suitable for making the minimum interference that the echoed signal from the bottom of container causes in conjunction with notional idea of radar signal diffraction, deflection and absorption.
Though various feature of the present invention is described as different embodiments of the invention, it will be apparent to one skilled in the art that these features can be combined so that the device that is fit to application-specific to be provided.
To be described embodiments of the invention by accompanying drawing now, wherein:
Fig. 1 illustrates the device according to the first embodiment of the present invention;
Fig. 2 illustrates second embodiment according to device of the present invention;
Fig. 3 illustrates diffractive geometries and different breakwater geometries;
Fig. 4 illustrates the detail drawing according to the polycrystalline substance of an embodiment of device of the present invention;
Fig. 5 illustrates the third embodiment of the present invention;
Fig. 6 illustrates described device is installed to diverse ways on the jar;
Fig. 7 illustrates the installation according to masking device of the present invention and described masking device;
Fig. 8 illustrates according to masking device of the present invention, comprises grid pattern;
Fig. 8 and 9 illustrates test result and to the analysis of these test results.
Fig. 1 illustrates the masking device 1 that is used for liquid level radar measurements, comprises ripple screen 2 and base section 3, and wherein, ripple screen 2 is communicated with (the not shown device that is used for the fluid connection) with liquid 4 fluids.This figure also illustrates stable pipe 5 and sway brace or fastener 6.In this embodiment, masking device 1 is shaped as container, and wherein, ripple screen 2 comprises the base section 3 of wall of a container and container bottom.Shown in this figure jar bottom 10 and polycrystalline substance 11.
Fig. 2 illustrates one embodiment of the present of invention, and wherein, ripple screen 2 only extends on the part of the periphery of base section 3.This figure also illustrates the perforation 12 on the ripple screen 2.
Fig. 3 A and 3B illustrate the diffractive geometries on the base section 3.These diffractive geometries also can be positioned on the ripple screen 2, and the combination of the diffractive geometries on ripple screen 2 and the base section 3 also is possible.Described accompanying drawing illustrates the different part of base section 3: 20,21,24,25,26, and described different part is positioned at (apart from d1 and d2) on the different surface levels.The edge of the described part of preferred combination (for example edge 22 and 23) overlapping, this allows to reduce the generation of the diffraction pattern of bottom clutter.For all parts, can be identical or different apart from d2, just a distance can be arranged between part 24 and part 27, and between part 24 and part 25, another distance be arranged.It will be understood by those skilled in the art that apart from the refractive index of d1 and d2 and liquid medium and the frequency of operation of radar and closely link together.Yet, may well provide the backscattering of diffraction to the careful modification of described distance, it is suitable for the geometric configuration of ripple screen admirably, thereby the energy (though being remaining) that reflects back into radar equipment is minimized.For example, can take the frequency of operation of 10GHz and the fluid of liquefied natural gas (LNG) (LNG), advise that described distance can be between 3 to 10 millimeters scope (distance that lower frequency requirement is bigger, vice versa).
Fig. 3 illustrates the different embodiment according to device of the present invention.Described accompanying drawing illustrates base section 34, and described base section is attenuator, ring 300,301 and breakwater 2 in a preferred embodiment of the invention, and described ring is fastened on the base section and blanking function is provided.
Fig. 3 C, 3D and 3E illustrate the different geometry (be respectively the polygon of cylindrical, odd number side and have the irregularly shaped of several or uneven limit) of base section 3.
Fig. 3 F illustrates an embodiment of base section 3, and wherein, described base section comprises the support ring 100 of braiding structure and rigidity.
Fig. 3 G illustrates one embodiment of the present of invention, and wherein, ripple screen 2 has the shape of ripple.The advantage that this embodiment has is that the inside standing wave in the masking device is decomposed apace by corner structure and disperses.
In Fig. 3 H-3K, the ripple screen comprises thin sheet metal or plastic material, i.e. stainless steel, aluminium, teflon or analog.In the embodiment shown in Fig. 3 L-3N, the ripple screen comprises braided material.The type of above-described different shape, wall construction and the design of microwave attenuator and geometry are combined in some embodiments of the invention thinks that various application and requirement provide best stabilising arrangement.
Figure 30 illustrates an embodiment according to device of the present invention, comprises plate 501, and it is suitable for being disposed between the rill of pot bottom.Plate 501 provides the bigger area that can settle masking device, considers radar pipe/radar-covered area, can settle with the best that obtains described masking device by mobile masking device on described plate.Plate 501 comprises the wall that ripple screen 2 is provided.Described masking device also comprises the screen or the wave absorber 500 of perforation.This figure also illustrates equalization chamber 502.
Fig. 3 P illustrates interchangeable embodiment of the present invention, wherein, comprises that ripple screen 2, the screen 500 of perforation and the columniform masking device of attenuator plate 34 are positioned on the board member 501.
Fig. 4 illustrates the detail drawing of the basic structural feature of relevant base section 3, and described base section comprises attenuating device in one embodiment of the invention.From top to bottom, described structure comprises metallic supports 31, and described metallic supports is configured to not contact described bottom near the bottom 10 of storage container (jar) as much as possible in preferred design.Extend the bottom that above-mentioned design feature requires support member to make its lower surface 32 be parallel to container (jar) fully, and simultaneously, and the upper surface 33 of described support member or base section can suitably comprise with respect to panel or the plane with the angle of inclination setting, the bottom of container.Second architectural feature of attenuating device 3 is absorbing materials 34, and described absorbing material is connected in the upper surface of support member to absorb most energy, and described energy penetrates liquid surface 4 downwards from stable pipe 5.Those skilled in the art expect easily, and the upper and lower surface of absorbing material 34 all may form about not the matching of radar signal wave propagation, thereby radar return can be given birth to very much in two surfaces.This double echo feature is used in the product commercial, described product generally refer to resonance absorber (
Layer), described resonance absorber is well suited for as the absorbing material in the attenuating device 3 34.As the further architectural feature of attenuating device 3, comprised the extra play of plastic material 35.The purpose of described layer mainly provides the protection of absorbing material, if necessary, considers simultaneously that also the expection of attenuator should be used for providing some relevant design freedoms that make the radar signal best performanceization of attenuator 3.In order to simplify this design freedom, in one embodiment of the invention, described attenuating device basis
Design can comprise the absorbing material 34 with high attenuation coefficient, and perhaps as an alternative, described absorbing material is extremely thick so that resonance can not be provided, thereby only the upper surface of remaining absorbing material produces detectable echo.Yet, can reduce this echo significantly by the plastic material 35 that makes one embodiment of the present of invention comprise that one deck has suitable thickness and a refractive index, thereby a kind of scheme also is provided, described scheme is
Design provides feasible alternative.
In addition, right
But the new feature and the creationary idea of the measuring position of scrutinizing the echo that makes the inventor expect 3 generations of relevant bottom attenuating device of design, this provides the useful aspect of using about the expection of described device.
The resonance character of layer will be eliminated backscattering, perhaps can be used to produce certain backscattering.But back one feature will make the detection position displacement of the echo of attenuating device 3 generations inevitably.But can make described displacement be provided at detection position below the support member 31 by careful selection, thereby the significant depth greater than the liquid of real depth also is provided absorbing material.The algorithm that is characterized as based on software that this is useful has provided the nargin that increases, and described algorithm can be used to solve the problem of liquid echo, the echo that described liquid echo produces from attenuating device 3.This key property of attenuating device 3 is applicable to equally well using the plastic material 35 that one deck has suitable thickness and refractive index to be thought
Design provides the situation of the above-mentioned alternative of mentioning.
Fig. 5 illustrates the third embodiment of the present invention, and wherein, masking device only comprises ripple screen 2, and described ripple screen 2 do not form the geometry of complete pipe, but partly opens wide.
Fig. 6 illustrates and is used for device 1 diverse ways that is installed on the jar.In Fig. 6 a, masking device is fastened on tripod guide 701 or the similar structures by carriage.This illustrate that described device is installed in pot bottom 10 but with its place separated by a distance (not contacting).Fig. 6 b illustrates and uses the independently metal-backed described device that is installed on the pot bottom 10.In this case, described device can or gluingly come fasteningly by bolt, welding, and contacts with pot bottom.Fig. 6 c illustrates and uses metal film to be installed in described device on the pot bottom as backing.Described device can or gluingly come fasteningly by bolt, welding, and this figure also illustrates a kind of clamping ring 700.
Fig. 7 a illustrates the location of one embodiment of the present of invention.In this embodiment, the base section 3 of masking device 1 comprises microwave attenuator, and is equipped with exhaust opening 600.This figure illustrates the metering height that the minimum of 26mm needs with full scale, in this case the lower surface of the base section 3 of 4mm and jar the bottom between distance, and the upper surface of the base section 3 of 8mm and jar the bottom between distance.This figure also illustrates a plate joint 610 and a jar barrier film 10, described plate joint shown in situation in (invar jar) have the height of 15mm.
Fig. 7 b illustrates an embodiment according to masking device 1 of the present invention, described masking device is equipped with fastener 800, and described masking device can be fixed on the tripod guidance structure by described fastener or any other is arranged on support member on the pot bottom 10.
Fig. 7 c illustrates an interchangeable location according to masking device 1 of the present invention, wherein, the carriage of described device is fixed on another carriage, and described another carriage is outstanding from described tripod guiding device, and stripping pump also is fixed on described tripod guidance structure place.
Fig. 7 d illustrates another possibility scheme of the location of relevant masking device 1.
Fig. 7 e illustrates the installation detail drawing with size.
Fig. 8 a illustrates the masking device with grid pattern.Masking device 1 comprises ripple screen 2 and base section 3.According to this embodiment of the invention, base section 3 comprises grid pattern layer 902.Lower surface corresponding to the described grid pattern of bottom layer 900 has the zone of different-thickness and quarter-wave rank 901 is provided.Attenuating material layer 34 is between grid pattern layer 902 and bottom layer 900.Make a kind of tester to be used for test purpose corresponding to Fig. 8 a.This tester comprises plastic material, and its impedance equals the impedance of kerosene, and this makes that flaggy all is sightless when being immersed in LNG and the kerosene.On the other hand, described flaggy is visible in air.Quarter-wave rank 901 and attenuating material 34 are suitable for removing the influence of reflection at the back side of cover sheet materials in this embodiment of the present invention.
As previously mentioned, in one embodiment of the invention, masking device is provided with fastener, is used for flaggy is fastened to attenuating material.In the idio-morphosis of this embodiment, described fastener is a screw, and described screw tightly is pressed downwardly onto described flaggy on the attenuating material, and base section is a rectangle, and described screw is installed near each shortwall symmetrically.
Fig. 8 b illustrates the masking device that is configured as container and comprises grid pattern.
Fig. 8 c-8g illustrates the result of the test that is immersed in the masking device in the kerosene.The specific inductive capacity that kerosene has approaches the specific inductive capacity of LNG.In measurement, be 147mm (in preliminary test is 72mm) to the distance of flaggy.The masking device that uses shown in Fig. 8 b, still is provided with trip bolt, and with the pipeline adhesive tape hole on the wall and leaky wall angle is clung to avoid the leakage of kerosene substantially.
It is the initial measurement of air that Fig. 8 c illustrates the flaggy top.Gamma (gamma)=1.98.Test result is almost desirable pulse (Gamma=2.00 is equivalent to desirable Hanning pulse), and is easy to detect (45dB) (noticing that pulse produces also and can ignore from testing tube when 0 loss).
Fig. 8 d is illustrated in the initial measurement that does not have liquid in the masking device, and this is the measuring condition that comprises planar metallic reflector (bottom of device) and top air.Gamma＝2.12。
Fig. 8 e is illustrated in the flaggy top and has the result of the test of 20mm kerosene.Well pulse, Gamma=2.08.Fig. 8 f is illustrated in the flaggy top and has the test result of 60mm kerosene.Gamma＝2.15。Fig. 8 g is illustrated in the flaggy top and has the test result of 140mm kerosene, Gamma=2.07.On the different liquid levels of kerosene these are measured and the center of gravity of similar measurement compares with the scale result in Fig. 9 a.
More than shown in the result prove that masking device is effectively, not have the echo of interference, and focus can move to degree of accuracy.In order to check this part, will compare with reference to (scale) reading and radar reading.In Fig. 9 a, can see radargrammetry and with the deviation between the kerosene liquid level of the nominal of tape measure.Fig. 9 a shows that standard deviation of these group data is 4.2mm, this be in desired+-accuracy rating of 5mm in.
Fig. 9 b illustrates the comparison of the level gauging of radar and scale.The standard deviation of measuring is 4.2mm, promptly precision+-5mm within.Shown in error bar, the estimation precision of tape measure (reference) is+-2mm.
Fig. 9 c illustrates the kerosene amplitude with liquid level change, and the result among this figure is consistent.
Above-described measurement shows that the shield assembly of rectangular shape does not produce very big unnecessary reflection.
Experiment also confirms to reduce to the liquid level place of 10-15mm above the flaggy and can obtain to be higher than+-precision of 5mm.
Though different feature of the present invention belongs to different embodiment by it and is described, some or all described features might be combined among the independent embodiment within the scope of the present invention.Thereby in one embodiment of the invention, described masking device comprises the perforation on blanker on the base section and the ripple screen.In another embodiment, the perforation that described masking device comprises on the base section and ripple shields, and be suitable for around stable pipe.In another embodiment, described masking device comprises only ripple screen, and described ripple screen is made by fiber mat basically.
Claims (18)
1. masking device that is used for liquid level radar measurements, it is characterized in that, described masking device is placed in to be stablized under the pipe and on the pot bottom, and comprise: can the flow ripple screen that passes, the base section that is equipped with the grid pattern flaggy and one deck of liquid is arranged on attenuating material on the described base section, wherein, the attenuating material layer comprises at least two zones, described at least two zones are positioned at apart from described grid pattern different distance place, and the border between described two zones is corresponding to the axis of symmetry of the lobe of radar beam.
2. masking device according to claim 1 is characterized in that, described ripple screen comprises perforation.
3. masking device according to claim 2, it is characterized in that, described masking device comprises base section, and described base section is suitable for using the blanker that is installed on the described base section will be from the minimum interference that radar signal produced of described jar bottom reflection.
4. masking device according to claim 1 is characterized in that, described masking device be suitable for using be installed in that described ripple screen is gone up or described base section on blanker will be from the minimum interference that radar signal produced of described jar bottom reflection.
5. masking device according to claim 4 is characterized in that described blanker is selected from attenuator, deflecting plate and diffraction structure.
6. masking device according to claim 5, it is characterized in that, described base section comprises resonance absorber weakening most of incident radar signal, and described resonance absorber produces and be detected on the locational little radar return of downward displacement, thereby increases effective liquid depth.
7. masking device according to claim 1 is characterized in that, described masking device comprises and is used for described flaggy is fastened to screw on the attenuating material layer.
8. masking device according to claim 1 is characterized in that one deck attenuating material is positioned under the described grid pattern.
9. masking device according to claim 1 is characterized in that, described base section is rectangle or square.
10. masking device according to claim 8 is characterized in that, described ripple screen is positioned at the main lobe of described radar beam.
11. masking device according to claim 1 is characterized in that, described masking device comprises the fastener that is used for described masking device is fastened to tripod guidance structure.
12. masking device according to claim 11 is characterized in that, described fastener comprises at least one articulation joint, and perhaps described fastener is made by thermal insulation material, and perhaps described fastener comprises extensible part.
13. masking device according to claim 3 is characterized in that, described masking device is shaped as container, and wherein, described ripple screen comprises described wall of a container, and described base section comprises the bottom of described container.
14. masking device according to claim 1 is characterized in that, described ripple screen is suitable for around stablizing pipe so that the multi-stag setting to be provided.
15. masking device according to claim 1 is characterized in that, described masking device is made or is covered by radar absorbing material at least in part.
16. masking device according to claim 1 is characterized in that, described masking device is made by fiber mat or the braided material or the similar material that comprise carbon fiber basically.
17. masking device according to claim 1 is characterized in that, described attenuating material layer comprises at least two zones, described at least two zones with the quarter-wave component level in apart from described grid pattern different distance place.
18. equipment that is used to measure liquid level, it comprises radargrammetry device and waveguide, described radargrammetry device has the antenna that is used for sending towards described liquid surface signal, it is characterized in that described equipment comprises according to each described masking device among the claim 1-17.
Applications Claiming Priority (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NO20054466 | 2005-09-27 | ||
| NO20054466A NO324464B1 (en) | 2005-09-27 | 2005-09-27 | Niva Templates |
| NO20054756A NO325428B1 (en) | 2005-10-14 | 2005-10-14 | Niva Templates |
| NO20054756 | 2005-10-14 | ||
| US73774305P | 2005-11-18 | 2005-11-18 | |
| US60/737743 | 2005-11-18 |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA2006800354349A Division CN101283240A (en) | 2005-09-27 | 2006-04-11 | Sheltering device for radar type liquid level measuring apparatus |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101825487A true CN101825487A (en) | 2010-09-08 |
| CN101825487B CN101825487B (en) | 2012-08-15 |
Family
ID=42689532
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2010101674357A Expired - Fee Related CN101825487B (en) | 2005-09-27 | 2006-04-11 | Sheltering device for radar type liquid level measuring apparatus |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JP4757919B2 (en) |
| CN (1) | CN101825487B (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105318936A (en) * | 2014-06-30 | 2016-02-10 | 罗斯蒙特储罐雷达股份公司 | Single conductor probe radar level gauge system and tank arrangement |
| CN107643113A (en) * | 2017-11-03 | 2018-01-30 | 湖北海洋工程装备研究院有限公司 | A kind of asphalt tanker stand alone type cargo tank liquid level emasuring device |
| TWI656354B (en) * | 2018-07-06 | 2019-04-11 | 國家中山科學研究院 | Ultra-material waveguide device and method for improving radar system signal-to-noise ratio law |
| CN112867940A (en) * | 2018-10-24 | 2021-05-28 | Abb瑞士股份有限公司 | Radar sensor and robot using the same |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19810601A1 (en) * | 1998-03-12 | 1999-09-16 | Daimler Benz Aerospace Ag | Arrangement for level measurement |
| SE513461C2 (en) * | 1999-10-21 | 2000-09-18 | Saab Marine Electronics | Device for level measurement in tanks |
| US6795015B2 (en) * | 2003-01-29 | 2004-09-21 | Saab Rosemount Tank Radar Ab | Bottom reflector for a radar-based level gauge |
-
2006
- 2006-04-11 CN CN2010101674357A patent/CN101825487B/en not_active Expired - Fee Related
- 2006-04-11 JP JP2008533280A patent/JP4757919B2/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105318936A (en) * | 2014-06-30 | 2016-02-10 | 罗斯蒙特储罐雷达股份公司 | Single conductor probe radar level gauge system and tank arrangement |
| CN105318936B (en) * | 2014-06-30 | 2019-09-27 | 罗斯蒙特储罐雷达股份公司 | Uniconductor probe radar level gauge system and tank arrangement |
| CN107643113A (en) * | 2017-11-03 | 2018-01-30 | 湖北海洋工程装备研究院有限公司 | A kind of asphalt tanker stand alone type cargo tank liquid level emasuring device |
| TWI656354B (en) * | 2018-07-06 | 2019-04-11 | 國家中山科學研究院 | Ultra-material waveguide device and method for improving radar system signal-to-noise ratio law |
| CN112867940A (en) * | 2018-10-24 | 2021-05-28 | Abb瑞士股份有限公司 | Radar sensor and robot using the same |
| CN112867940B (en) * | 2018-10-24 | 2023-03-24 | Abb瑞士股份有限公司 | Radar sensor and robot using the same |
Also Published As
| Publication number | Publication date |
|---|---|
| CN101825487B (en) | 2012-08-15 |
| JP2009510430A (en) | 2009-03-12 |
| JP4757919B2 (en) | 2011-08-24 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US9091584B2 (en) | Microwave window and level-measuring system that works according to the radar principle | |
| US7345622B2 (en) | Two-mode radar level gauge system | |
| EP2659237B1 (en) | High frequency mode generator for radar level gauge | |
| EP3087355B1 (en) | Guided wave radar level gauging with probe retaining element | |
| WO1996025647A1 (en) | A method and apparatus for level gauging using radar in floating roof tanks | |
| US9000775B2 (en) | Fill-level measuring device for ascertaining and monitoring fill level of a medium located in the process space of a container by means of a microwave travel time measuring method | |
| EP1962066B1 (en) | Fluid level measurement device | |
| CN101825487B (en) | Sheltering device for radar type liquid level measuring apparatus | |
| JPS6128825A (en) | Method and device for measuring level of fluid material in vessel | |
| US20120007768A1 (en) | Radar level gauge system with bottom reflector and bottom reflector | |
| EP1794551B1 (en) | Radar level gauge comprising a sealing unit with microwave blocking means | |
| US5781019A (en) | Probe for use in time domain reflectometry | |
| JP4499972B2 (en) | Device for measuring the level in a container | |
| KR20070045888A (en) | Level gauge | |
| KR101162469B1 (en) | Device for sloshing monitoring in tank of liquified natural gas carrier | |
| KR100952536B1 (en) | Sheltering device | |
| CN103364051A (en) | Material level measuring device and adapter with reflector | |
| CN101283240A (en) | Sheltering device for radar type liquid level measuring apparatus | |
| JP2006515068A (en) | Bottom reflector for radar level gauge | |
| US20230034044A1 (en) | Fluid level measurement system using buoyant body | |
| KR101856466B1 (en) | Lng ship tank simulation system | |
| KR20070035402A (en) | Sheltering device | |
| CN107643113A (en) | A kind of asphalt tanker stand alone type cargo tank liquid level emasuring device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20120815 Termination date: 20150411 |
|
| EXPY | Termination of patent right or utility model |