DK151544B - ICE FORMATION DETECTOR - Google Patents
ICE FORMATION DETECTOR Download PDFInfo
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- DK151544B DK151544B DK572173A DK572173A DK151544B DK 151544 B DK151544 B DK 151544B DK 572173 A DK572173 A DK 572173A DK 572173 A DK572173 A DK 572173A DK 151544 B DK151544 B DK 151544B
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- 230000015572 biosynthetic process Effects 0.000 title claims description 88
- 238000005755 formation reaction Methods 0.000 claims description 87
- 239000000523 sample Substances 0.000 claims description 63
- 230000005855 radiation Effects 0.000 claims description 22
- 239000003570 air Substances 0.000 claims description 21
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 20
- 238000010438 heat treatment Methods 0.000 claims description 16
- 239000012080 ambient air Substances 0.000 claims description 10
- 238000009792 diffusion process Methods 0.000 claims description 6
- 230000009849 deactivation Effects 0.000 claims description 4
- 230000000903 blocking effect Effects 0.000 claims description 3
- 238000002844 melting Methods 0.000 claims description 3
- 230000008018 melting Effects 0.000 claims description 3
- 238000005070 sampling Methods 0.000 claims description 3
- 230000004913 activation Effects 0.000 claims description 2
- 230000010354 integration Effects 0.000 claims 2
- 230000003213 activating effect Effects 0.000 claims 1
- 230000001419 dependent effect Effects 0.000 claims 1
- 238000000034 method Methods 0.000 claims 1
- 230000007704 transition Effects 0.000 claims 1
- 238000001514 detection method Methods 0.000 description 7
- 230000000694 effects Effects 0.000 description 3
- 230000035945 sensitivity Effects 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000007257 malfunction Effects 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005485 electric heating Methods 0.000 description 1
- 238000007710 freezing Methods 0.000 description 1
- 230000008014 freezing Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000012886 linear function Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 230000003595 spectral effect Effects 0.000 description 1
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64D—EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
- B64D15/00—De-icing or preventing icing on exterior surfaces of aircraft
- B64D15/20—Means for detecting icing or initiating de-icing
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01W—METEOROLOGY
- G01W1/00—Meteorology
- G01W1/14—Rainfall or precipitation gauges
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- Biodiversity & Conservation Biology (AREA)
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- Aviation & Aerospace Engineering (AREA)
- Indicating Or Recording The Presence, Absence, Or Direction Of Movement (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
- Solid Thermionic Cathode (AREA)
- Investigating Or Analyzing Materials Using Thermal Means (AREA)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
- Geophysics And Detection Of Objects (AREA)
- Emergency Alarm Devices (AREA)
Description
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Opfindelsen angår en isdannelsesdetektor med en i et rørelement monteret isdannelsesprobe og et føleorgan til detektering af tilstedeværelse af is på isdannelsesproben.The invention relates to an ice formation detector with an ice formation probe mounted in a tubular element and a sensing means for detecting the presence of ice on the ice formation probe.
Selvom isdannelsesdetektorer er kendte, eksisterer der et behov for isdannelsesdetektorer, som kan arbejde under stærkt varierende lufthastigheder i omgivelserne eller i tilfælde, hvor lufthastigheden er utilstrækkelig til at give en passende følsomhed. Sådanne detektorer anvendes f.eks. i høje konstruktioner som bygninger og tårne, i fartøjer, i stationære gasturbineinstallationer og i luftfartøjer til lodret start og landing.Although ice formation detectors are known, there is a need for ice formation detectors which can operate at widely varying ambient air velocities or in cases where the air velocity is insufficient to provide adequate sensitivity. Such detectors are used e.g. in tall structures such as buildings and towers, in vessels, in stationary gas turbine installations and in aircraft for vertical take-off and landing.
I en helikopter er en isdannelsesdetektor af stor betydning, hvis helikopteren skal kunne udføre flyveoperationer i alle slags vejrlig, som følge af det store område af lufthastigheder, indenfor hvilket en helikopter kan arbejde. Den 2 151544 di rotorbladene som følge af deres forholdsvis ringe vægt og høje hastighed har en kraftig tilbøjelighed til dråbeindfangning, medens helikopterens ikke-roterende dele af modsatte årsager har en meget lav tilbøjelighed til dråbeindfangning, navnlig ved lave flyvehastigheder. En isdannelsesdetektor er derfor nødvendig for at give piloten tidligt varsel om begyndende isdannelse, således at han kan tage de nødvendige forholdsregler. Hvis helikopteren endvidere er udstyret med et system til beskyttelse af rotorbladene mod isdannelser, indgår en isdannelsesdetektor som en nødvendig komponent i et sådant system som følge af behovet for øjeblikkelig aktivering af systemet ved begyndende isdannelse og for en nøjagtig kontrol med den tilladelige islagstykkelse, hvor et sådant system arbejder efter et afisningsprincip. Til opnåelse heraf er det nødvendigt, at isdannelsesdetektoren har en høj følsomhed, dvs. er i stand til detektering af små ismængder, og reagerer hurtigt. Den angivelse af isdannelseshastigheden, soro frembringes af detektoren, skal være nært knyttet til hastigheden for isdannelse på rotorbladene, som kun i mindre grad er påvirket af flyvehastigheden på grund af rotorbladenes høje omdrejningshastighed.In a helicopter, an ice formation detector is of great importance if the helicopter is to be able to perform flight operations in all kinds of weather, due to the large range of air speeds within which a helicopter can operate. The 2 151544 di rotor blades due to their relatively low weight and high speed have a strong tendency to drop capture, while the non-rotating parts of the helicopter for opposite reasons have a very low tendency to drop capture, especially at low flight speeds. An ice formation detector is therefore necessary to give the pilot early warning of incipient ice formation so that he can take the necessary precautions. Furthermore, if the helicopter is equipped with a system for protecting the rotor blades against ice formation, an ice formation detector is included as a necessary component in such a system due to the need for immediate activation of the system at the beginning of ice formation and for an accurate control of the allowable ice layer thickness. such a system operates on a de-icing principle. To achieve this, it is necessary that the ice formation detector has a high sensitivity, i.e. is capable of detecting small amounts of ice, and responds quickly. The indication of the rate of ice formation produced by the detector must be closely related to the rate of ice formation on the rotor blades, which is only slightly affected by the flight speed due to the high rotational speed of the rotor blades.
De fleste eksisterende typer af isdannelsesdetektorer til såvel luftbåren som stationær anvendelse bygger på den naturlige relative hastighed mellem den dråbeladede luft og detektorens følsomme overflade, som følge af hvilken underafkølede vanddråber afsættes på denne overflade. Tilstedeværelsen af vand i enten flydende eller fast form på den følsomme overflade detekteres på forskellig måde.Most existing types of ice formation detectors for both airborne and stationary use are based on the natural relative velocity between the droplet-charged air and the sensitive surface of the detector, as a result of which subcooled water droplets are deposited on this surface. The presence of water in either liquid or solid form on the sensitive surface is detected in different ways.
Da hastigheden for dråbernes nedslag -på overfladen er en funktion af den relative hastighed, vil apparatets reaktionshastighed også være en funktion af den relative hastighed og aftage med aftagende hastighed. Visse typer af detektorer kræver endvidere et vist minimum af relativ hastighed til detektering af isdannelser.Since the velocity of the droplets on the surface is a function of the relative velocity, the reaction rate of the apparatus will also be a function of the relative velocity and decrease with decreasing velocity. Furthermore, certain types of detectors require a certain minimum of relative speed for detecting ice formations.
Til isdannelsesdetektering i helikoptere anvendes idag flyisdannelsesdetektorer af standardtype monteret enten på understellet, i motoren eller i lufttilgangskanalen. Med disse indretninger har der ikke kunnet opnås en tilfredsstillende isdannelsesdetektering eller data for isdannelseshastighed, som er anvendelige til styring af isdannelsesbeskyttelsessystemer for rotorblade, fordi der ikke er nogen entydig sammenhæng mellem den isdannelseshastighed, som affødes af isdannelsesdetektoren og den, som rotorbladene er udsat for. Endvidere er det ikke ønskeligt at montere en isdannelsesdetektor i motorens lufttilgangskanal på grund af risikoen for motorbeskadigelse forårsaget af is, som afkastes fra detektoren. Det har været foreslået at montere en isdannelsesdetektor på selve rotorbladet, altså anbringe den der, hvor der ønskes et- mål for isdannelsen. Dette forslag har imidlertid ikke vundet tilslutning på grund af de komplikationer med hensyn til glide-ringe og andre organer, som kræves til overføring af effekt og detektorsignaler mellem roterénde dele, og vanskelighederne ved at indkorporere detektoren i rotorbladskonstruktionen. De fleste eksisterende isdannelsesdetektorer er udformet 3 151544 til detektering af tilstedeværelsen eller fraværet af isdannelser, men ikke til frembringelse af et kvantitativt udtryk for omfanget af denne tilstand.For ice formation detection in helicopters, standard flight formation detectors mounted today are mounted either on the chassis, in the engine or in the air access duct. With these devices it has not been possible to obtain a satisfactory icing detection or icing rate data useful for controlling icing protection systems for rotor blades because there is no unambiguous relationship between the icing rate generated by the icing detector and the one to which the rotor blades are exposed. Furthermore, it is not desirable to mount an ice formation detector in the engine air supply duct due to the risk of engine damage caused by ice being ejected from the detector. It has been proposed to mount an ice formation detector on the rotor blade itself, ie to place it where a target for ice formation is desired. However, this proposal has not been approved due to the complications with respect to sliding rings and other means required for transmitting power and detector signals between rotating parts, and the difficulty of incorporating the detector into the rotor blade assembly. Most existing ice formation detectors are designed to detect the presence or absence of ice formation, but not to produce a quantitative expression of the extent of this condition.
Ved den foreliggende opfindelse tilsigtes det at frembringe en detektor, som uafhængigt af den relative lufthastighed i omgivelserne har en høj følsomhed, og hvis reaktionshastighed er upåvirkelig af lufthastigheden i omgivelserne, således at detektoren på pålidelig måde er i stand til at angive isdannelsesforholdene i omgivelserne.The present invention aims to provide a detector which, independently of the relative ambient air velocity, has a high sensitivity and whose reaction rate is unaffected by the ambient air velocity, so that the detector is reliably capable of indicating the ambient ice formation conditions.
Dette opnås ifølge opfindelsen ved, at der ved rørelementets ene ende er udformet et overtryksrum, hvorhos der findes midler til tilførsel af en gasart under tryk til overtryksrummet og i tilknytning til rørelementets indre er anbragt et med overtryksrummet kommunikerende primært dyseorgan til injektion af en sekundær omgivelsesluftstrøm over isdannelsesproben. Den gennem rørelementet med høj hastighed inducerede luftstrøm er i det væsentlige konstant uafhængigt af lufthastigheden i omgivelserne, således at der i rørelementet opnås en høj vanddråbef luks. Isdannelsen sker ved, at proben rammes af underafkølede vanddråber. Ved periodisk fjernelse af den resulterende isdannelse ved opvarmning af proben, når der er dannet en forud bestemt ismængde, opnås en isdannelses/afisnings-cyk-lus, som udnyttes til frembringelse af enten diskrete isdannelsessignaler eller et kvantitativt mål for isdannelseshastigheden. Da lufthastigheden i rørelementet er omtrent konstant, vil isdannelseshastigheden på proben være en direkte funktion af indholdet af underafkølede vanddråber, der derfor kan benyttes til måling af den betydningsfulde isdannelsesparameter. Endvidere har den forøgede hastighed gennem rørelementet som følge af temperatufaldet en afkølende virkning, således at der opretholdes konstant enthalpi. Som følge heraf har føleorganet en stærkere tilbøjelighed til isdannelse end det luftfartøj eller anden konstruktion, hvortil det er knyttet.This is achieved according to the invention in that an overpressure space is formed at one end of the pipe element, in which means there are means for supplying a gas under pressure to the overpressure space and in connection with the interior of the pipe element a primary nozzle means communicating with the overpressure space for injecting a secondary ambient air flow. over ice formation probes. The air flow induced through the high-velocity pipe element is substantially constant, independent of the ambient air velocity, so that a high drop of water droplet is obtained in the pipe element. Ice formation occurs when the probe is hit by subcooled water droplets. By periodically removing the resulting ice formation by heating the probe when a predetermined amount of ice has formed, an ice formation / defrost cycle is obtained which is utilized to generate either discrete ice formation signals or a quantitative measure of the ice formation rate. Since the air velocity in the tube element is approximately constant, the rate of ice formation on the probe will be a direct function of the content of subcooled water droplets, which can therefore be used to measure the significant ice formation parameter. Furthermore, the increased velocity through the tube element due to the temperature drop has a cooling effect, so that constant enthalpy is maintained. As a result, the sensing means has a stronger tendency to ice than the aircraft or other structure to which it is attached.
Den inducerede luftstrøm gennem rørelementet kan på passende måde opnås ved hjælp af et ejektionsorgan. Hvis der som primær strøm i ejektionsorganet benyttes en opvarmet gasart, kan denne udnyttes til afisning af detektorkonstruktionen. Primærdysen for den opvarmede gasart må anbringes således, at opvarmning af isdannelsesproben eller den omgivende luft, der kommer i berøring med proben, undgås.The induced air flow through the tubular element can be suitably obtained by means of an ejection means. If a heated gas is used as the primary current in the ejection means, this can be used for deicing the detector construction. The primary nozzle for the heated gas must be placed so that heating of the ice-forming probe or the ambient air that comes into contact with the probe is avoided.
Til den periodiske smeltning af isdannelser på proben kan der findes midler til opvarmning af denne, hvilke opvarmningsmidlers aftivering og afaktivering styres af føleorganet. Ved isfjernelse på denne måde er det vigtigt at undgå, at isfjerne.lsen på den del af proben, hvor føleorganet detekterer is, sker hurtigere end på probens øvrige dele, idet der ellers vil være risiko for en sådan vækst i den efter opvarmningsmidlernes afaktivering tilbageblevne isdannelse på disse øvrige dele, at der opstår blokering af rørelementet og deraf følgende fejlfunktion.For the periodic melting of ice formations on the probe, means can be found for heating it, which deactivation and deactivation of heating means are controlled by the sensing means. When removing ice in this way, it is important to avoid that the ice removal on the part of the probe where the sensing means detects ice takes place faster than on the other parts of the probe, as otherwise there will be a risk of such growth in the residue left after deactivation of the heating means. ice formation on these other parts, that blockage of the pipe element and consequent malfunction occurs.
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Ved en udførelselform for isdannelsesdetektoren ifølge opfindelsen undgås den nævnte risiko, således at en pålidelig og fejlfri funktion opretholdes ved, at probeopvarmningsmidlerne udgøres af et elektrisk modstandselement, hvoraf en del, ved hvilken der detekteres is, har formindsket elektrisk resistans i forhold til isdannelsesprobens øvrige dele. Herved vil opvarmning af den del af proben, pa hvilken der detekteres is, ske en smule langsommere end i resten af proben med deraf følgende langsommere fjernelse af isdannelsen på den nævnte del, hvorigennem det sikres, at isdannelsen fjernes på hele proben inden opvarmningen afbrydes.In an embodiment of the ice formation detector according to the invention, the said risk is avoided, so that a reliable and fault-free function is maintained by the probe heating means being constituted by an electrical resistance element, a part of which ice is detected has reduced electrical resistance compared to the other parts of the ice formation probe. . Hereby heating of the part of the probe on which ice is detected will take place a little slower than in the rest of the probe with consequent slower removal of the ice formation on said part, thereby ensuring that the ice formation is removed on the whole probe before the heating is interrupted.
I det følgende forklares opfindelsen nærmere under henvisning til tegningen, hvor fig. 1 viser et snit af en del af en isdannelsesdetektor ifølge opfindelsen, fig. 2 et snit efter linien II-II i fig. 1, fig. 3-5 snitbilleder af forskellige andre udførelsesformer for detektoren, fig. 6 et snit efter linien VI-VI i fig.5, fig. 7-10 diagrammer for forskellige udførelsesformer af det elektriske kredsløb i detektoren og, fig. 11 en grafisk afbildning til til illustration af isdannelsescyklen.In the following, the invention is explained in more detail with reference to the drawing, in which fig. 1 shows a section of a part of an ice formation detector according to the invention, fig. 2 is a section along the line II-II in fig. 1, fig. 3-5 are sectional views of various other embodiments of the detector, fig. Fig. 6 is a section along the line VI-VI in Fig. 5; 7-10 diagrams of different embodiments of the electrical circuit in the detector and, fig. 11 is a graphical illustration for illustrating the icing cycle.
Detektoren 1 i fig. 1 indeholder et rørformet element 2 med et overtryksrum 3 udformet i sin forreste ende. Overtryksrummet åbner sig bagtil ind i det rørformede element gennem en ringformet promærdyse 4, gennem hvilken en gasart dirigeres bagud langs rørelementet 2's indvendige overflade 5. Med primærgassen induceres en forøget luftstrøm gennem rørelementet 2, og hvis primærgassen er opvarmet, holdes rørelementet herigennem fri for is. Gassen tilføres overtryksrummet 3 gennem en tilførselsledning 6, der er forbundet til en passende kilde som f.eks. en kompressor.The detector 1 in fig. 1 contains a tubular element 2 with an overpressure space 3 formed at its front end. The overpressure space opens at the rear into the tubular element through an annular primary nozzle 4, through which a gas is directed backwards along the inner surface 5 of the tubular element 2. With the primary gas an increased air flow is induced through the tubular element 2, and if the primary gas is heated, the tubular element is kept free of ice. . The gas is supplied to the overpressure space 3 through a supply line 6, which is connected to a suitable source such as e.g. a compressor.
På tværs i rørelementet er monteret en isdannelsesprobe 7. Til smeltning af den på proben dannede is findes passende elektriske opvarmningsorganer.An ice-forming probe 7 is mounted across the pipe element. Suitable electric heating means are available for melting the ice formed on the probe.
Proben 7 og primærdysen 4 har en sådan indbyrdes beliggenhed, at opvarmet luft for primærdysen ikke opvarmer proben eller den omgivelsesluft., som kommer i berøring med den. Ved hjælp af.-passende spærreorganer 11 afbøjes primærluftstrømmen omkring proben 7, således at den opvarmede gas forhindres i at opvarme proben 7. ..The probe 7 and the primary nozzle 4 have such a mutual position that heated air for the primary nozzle does not heat the probe or the ambient air which comes into contact with it. By means of suitable blocking means 11, the primary air flow around the probe 7 is deflected, so that the heated gas is prevented from heating the probe 7.
Rørelementet 2 omfatter tre sektioner, nemlig en indgangssektion 13 med aerodynamisk glat udformning, en kort blandesektion 14 og en diffusionssektion 15. Det forhold, at der anvendes ingen eller kun en ringe blandemængde foran diffusionssektionen, medfører at strømningsforøgelsen bliver uvirksom. San følge heraf opnås en næsten konstant hastighed af sekundærluften i vidt område af omgivelsesluf thastigheder.The tube element 2 comprises three sections, namely an inlet section 13 with aerodynamically smooth design, a short mixing section 14 and a diffusion section 15. The fact that no or only a small amount of mixing is used in front of the diffusion section causes the flow increase to become ineffective. As a result, an almost constant velocity of the secondary air is achieved over a wide range of ambient air velocities.
5 151544 I rørelementet 2 er monteret en strålingskilde 8 og et føleorgan 9 som. samvirker med isdannelsesproben 7 til detektering af tilstedeværelsen af is under udelukkelse af direkte stråling fra strålingskilden 8 til føleorganet 9. Til detektering af tilstedeværelsen af is på proben skærer forbindelseslinien mellem.strålingskilden og føleorganet rørelementets længdeakse i en afstand foran probens fremadvendende del svarende tilnærmelsesvis til den halve bredde af et strålebundt. Fortrinsvis skærer forbindelseslinien den nævnte længdeakse under en stor vinkel, f.eks. 45° eller mere.A radiation source 8 and a sensing means 9 are mounted in the tube element 2. cooperates with the ice-forming probe 7 for detecting the presence of ice excluding direct radiation from the radiation source 8 to the sensing means 9. To detect the presence of ice on the probe, the connecting line intersects the radiation source and the sensing means longitudinal axis of the tube element half the width of a beam. Preferably, the connecting line intersects said longitudinal axis at a large angle, e.g. 45 ° or more.
Ved anbringelse af strålingskilden og -føleorganet umiddelbart bag dysen 4 holdes vinduerne 18 og 19 fri for urenheder af den med høj hastighed udstrømmende primære gasstrøm.By placing the radiation source and sensing means immediately behind the nozzle 4, the windows 18 and 19 are kept free of impurities by the high-velocity primary gas stream flowing out.
Da overtryksrummet 3 tilføres opvarmet luft og er beliggende ved rørelementets forreste ende, tjener det til at holde denne del af røreleaæntet fri for is.Since the overpressure space 3 is supplied with heated air and is located at the front end of the pipe element, it serves to keep this part of the pipe element free of ice.
Som vist i fig. 1 kan rørelementet på sin udvendige overflade have en diskontinuitet 12. Herved forhindres vand i at løbe tilbage fra den opvarmede forende til rørelementets udgang, hvilket under visse- betingelser kunne bevirke opbyggelse af et islag omkring bagkanten og ind i rørelementets indre. Diskontinuiteten 12 bevirker, at det meste af det vand, der løber tilbage langs siden, blæses væk ved denne diskontinuitet.As shown in FIG. 1, the pipe element on its outer surface may have a discontinuity 12. This prevents water from flowing back from the heated front end to the outlet of the pipe element, which under certain conditions could cause an ice layer to build up around the rear edge and into the interior of the pipe element. The discontinuity 12 causes most of the water running back along the side to be blown away by this discontinuity.
I fig. 1 og 2 er proben rørformet og har en plan flade omkring midtpunktet af den fremadvendende side. Denne plane flade sikrer detektering af enhver form for isdannelse, medens der med en cylindrisk probe under visse atmosfæriske forhold kunne dannes is ved cylinderens ender, medens den fremadvendende side forblev fri for is. Dette ville optræde i et område af lufttemperaturer umiddelbart under ligevægtsfrysepunktet fra vand som følge af den varierende varmebalance omkring en cylinder. Under disse forhold ville isdannelsen ikke brede sig fremefter i tilstrækkeligt omfang for detektering. Ved at udforme probens fremadvendende side med en plan flade, ved den høje dråbeindfangningsevne og det høje konvektionsvarmetab ved kantén af den plane flade resulterer i isdannelse på dette sted, hvorved der.muliggøres detektering af isdannelse ved temperaturer, son ligger nærmere 0° C end muligt med en cylindrisk probe.In FIG. 1 and 2, the probe is tubular and has a flat surface about the center of the forward-facing side. This flat surface ensures the detection of any kind of ice formation, while with a cylindrical probe, under certain atmospheric conditions, ice could form at the ends of the cylinder, while the forward-facing side remained free of ice. This would occur in a range of air temperatures immediately below the equilibrium freezing point of water due to the varying heat balance around a cylinder. Under these conditions, ice formation would not propagate forward sufficiently for detection. By designing the forward side of the probe with a flat surface, at the high droplet capture ability and the high convection heat loss at the edge of the flat surface results in ice formation at this location, thereby enabling detection of ice formation at temperatures closer to 0 ° C than possible with a cylindrical probe.
I tilfælde hvor isdannelse ved relativ høj temperatur har ingen eller kun ringe virkning, kan strålebundtet orienteres aksialt langs forkanten af en cylindrisk probe, således at der kun detekteres is, senn dannes netop på forkanten af stilstandsområdet.In cases where ice formation at relatively high temperature has no or little effect, the beam can be oriented axially along the leading edge of a cylindrical probe so that only ice is detected, then formed precisely on the leading edge of the standstill area.
Proben er indrettet til at blive afiset ved hjælp af elektrisk .strøm. Da varmen afkobles ved fjernelse af den is, som ligger i banen for strålebundtet, er der en risiko for, at der hvis is i dette område fjernes inden is på probens 151544 j 6 øvrige dele, i løbet-af et antal isdannelses/afisnings-cykler kunne ske en vakst ' i denne tilbageblevne isdannelse, hvilket kunne forårsage blokering af rørelementet og resulterer i fejlfunktion. For at undgå dette er probens-centrale område ved den plane flade udformet således, at opvarmningen her sker en smule langsommere end i resten af proben, således at isen i føleområdet fjernes sidst. Dette kan opnås; gennem en let reduktion af den elektriske resistans i probens midte ved anvendelse af en tynd ringformet metalplettering.The probe is designed to be de-iced using electric .current. As the heat is dissipated by removing the ice which lies in the path of the beam, there is a risk that if ice in this area is removed before ice on the other parts of the probe 151544 j 6 other parts, during a number of ice-forming / de-icing cycles could cause a growth in this residual ice formation, which could cause blockage of the tubular member and result in malfunction. To avoid this, the central area of the probe at the flat surface is designed so that the heating here takes place a little slower than in the rest of the probe, so that the ice in the sensing area is removed last. This can be achieved; through a slight reduction of the electrical resistance in the center of the probe by using a thin annular metal plating.
I fig. 3-6 er vist andre udformninger af primærdysen. Fig. 3 viser diskrete primærdyseorganer 34, der står i forbindelse med overtryksrummet gennem kanaler i rørelementet 32. Ligesom i udførelsesformen i fig. 1 og 2 indeholder detektoren en isdannelsesprobe 37 og et føleorgan 38. I fig. 4 er vist en enkelt primærdyse 44 anbragt koaksialt i rørelementet 42 med tilførsel af primærgas fra overtryksrummet 43. I fig. 5 og 6 forløber en ringformet primær-. dyse 54 ved sin udmunding parallelt med rørelementet 52's akse i stedet for at konvergere som vist i fig. 1. Dette resulterer i en mindre turbulent strømning af luft med høj hastighed forbi vinduerne 58 og 59, hvorved virkningen med hensyn til forhindring af aflejringer af snavs på vinduerne forbedres.In FIG. 3-6 show other designs of the primary nozzle. FIG. 3 shows discrete primary nozzle means 34 which communicate with the overpressure space through channels in the pipe element 32. As in the embodiment in fig. 1 and 2, the detector contains an ice-forming probe 37 and a sensing means 38. In fig. 4 shows a single primary nozzle 44 arranged coaxially in the pipe element 42 with the supply of primary gas from the overpressure space 43. In fig. 5 and 6, an annular primary. nozzle 54 at its mouth parallel to the axis of the tube member 52 instead of converging as shown in FIG. This results in a less turbulent flow of high velocity air past windows 58 and 59, thereby improving the effect of preventing dirt deposits on the windows.
I fig. 5 og 6.er illustreret en andén mulighed for afbøjning af primærstrømmen omkring proben 57 ved forlængelse af de isolerende bøsninger 55, hvis primære funktion er at isolere proben 57 fra rørelementets væg, med et stykke i det væsentlige lig med primærdysens tykkelse.In FIG. 5 and 6 illustrate another possibility of deflecting the primary flow around the probe 57 by extending the insulating bushings 55, whose primary function is to insulate the probe 57 from the wall of the tubular member, by a piece substantially equal to the thickness of the primary nozzle.
________De jl^ fig. 1 og 5 viste -ringformede primær dysa: er mere effektive end diskrete vægdyser som vist i fig* 3 eller en central dyse som vist i fig. 4, fordi primærstrømmen, der har høj energi, overalt er i kontakt med væggen, således at der ikke kræves nogen blandet længde før diffusionen, og der også muliggøres anvendelse af en mere vidvinklet og dermed kortere diffusionssektion. Den højere virkningsgrad er imidlertid som anført ovenfor en ulempe, som afbalanceres med muligheden for en kortere diffusionssektion,- der resulterer i en mindre og lettere enhed. Endvidere vil vand, som løber tilbage i rørelementet fra den opvarmede forende, blive brudt op af primærdysen uden at komme i kontakt med rørelementets væg,. hvorved risikoen for isdannelse inde i rørelementet og dermed behovet for eventuel yderligere opvarmning i rørelementet fjernes.________De jl ^ fig. 1 and 5 are more efficient than discrete wall nozzles as shown in Fig. 3 or a central nozzle as shown in Figs. 4, because the primary energy, which has high energy, is everywhere in contact with the wall, so that no mixed length is required before the diffusion, and it is also possible to use a wider-angled and thus shorter diffusion section. However, as stated above, the higher efficiency is a disadvantage which is balanced by the possibility of a shorter diffusion section, - resulting in a smaller and lighter unit. Furthermore, water flowing back into the tubular member from the heated front end will be broken up by the primary nozzle without coming into contact with the wall of the tubular member. whereby the risk of ice formation inside the pipe element and thus the need for any further heating in the pipe element is removed.
Det har vist sig, at en passende strålingskilde og -detektor udgøres af en infrarødt lys udsendende diode og en fototransistor. Ved anvendelse af en fototransistor med-bredt spektralsvar kan der foran føleorganet anbringes et for infrarød stråling gennemsigtigt, men for synligt lys ugennemsigtigt filter. San en anden mulighed eller i tilgift kan den udsendte stråling moduleres for at muliggøre afvisning af omgivelsesstrålingen.It has been found that a suitable radiation source and detector is constituted by an infrared light emitting diode and a phototransistor. When using a phototransistor with a broad spectral response, a filter which is transparent to infrared radiation but which is opaque to visible light can be placed in front of the sensing means. If possible or in addition, the emitted radiation can be modulated to enable the ambient radiation to be rejected.
7 1515447 151544
Da den hastighed, hvormed tværsnitsarealet af det infrarøde strålebundt afskæres mellem 25% og 75% afskæring, med god tilnærmelse er en lineær funktion af isdannelseshastigheden på proben, kan afskæringshastigheden inden for dette vindue benyttes til opnåelse af et udtryk for isdannelseshastighedert på proben.Since the rate at which the cross-sectional area of the infrared beam is cut between 25% and 75% cut-off is, with good approximation, a linear function of the icing rate of the probe, the cut-off rate within this window can be used to obtain an expression of icing rate on the probe.
En med afskæringshastigheden proportional spænding kan opnås ved elektronisk differentiation af udgangsspændingen fra det infrarøde- føleorgan og tilførsel af det differentierede signal til et måleinstrument eller et andet udlæsnings- eller registreringsapparat i den tilnærmelsesvis lineære midterdel af-afskæringsområdet. Uden for denne del spærres udlæsningen eller fastholdes på den sidst indtagne værdi.A voltage proportional to the cut-off speed can be obtained by electronically differentiating the output voltage from the infrared sensing means and applying the differentiated signal to a measuring instrument or other reading or recording apparatus in the approximately linear central part of the cut-off area. Outside this part, the readout is blocked or maintained at the last input value.
Afskæringshastigheden kan benyttes til bestemmelse af vandindholdet, når lufthastigheden forbi proben holdes konstant. Ved at indføre en luftstrøm med høj hastighed i forhold til hastigheden af omgivelsesluften i rørelementet vil lufthastigheden blive holdt i det væsentlige konstant, således at der ud fra afskæringshastigheden kan opnås et godt mål for indholdet af underafkølét vand.The shear rate can be used to determine the water content when the air velocity past the probe is kept constant. By introducing an air flow with a high velocity in relation to the velocity of the ambient air in the pipe element, the air velocity will be kept substantially constant, so that from the cutting speed a good measure of the content of subcooled water can be obtained.
Som vist i fig. 7 drives den infrarøde strålingskilde af en passende spændingskilde 75. Om ønskes kan der være tilføjet en modulator 74 til frembringelse af pulseret stråling. Isdannelsesproben 77 er anbragt således i forhold til strålekilden 78 og føleorganet 79, at is opbygget på proben 77 progressivt vil spærre for overføringen af infrarød stråling med et heraf følgende fald i signalniveauet. Dette signal afføles og forstærkes i en forstærker Al, hvorefter det sammenlignes med to referencesignaler fra.forstærkere Ag og A^ i spændingskomparatorer A^ og A^, der er dimensioneret-til dannelse-af en vinduesdetektor. Komparatorernes udgangssignalniveau afhænger af indgangssignalets størrelse i forhold til vinduesdetektorens lysåbning og er bestemmende for tilstanden af en flip-flopkreds F^. Denne styrer effekttilførslen til et opvarmningsorgan 76 for detektorproben og en signallampe 71 over et opvarmningsstyreorgan 72. Isdetekteringscykien er illustreret i fig. 11.As shown in FIG. 7, the infrared radiation source is driven by a suitable voltage source 75. If desired, a modulator 74 for generating pulsed radiation may be added. The ice formation probe 77 is positioned relative to the radiation source 78 and the sensing means 79 so that ice built up on the probe 77 will progressively block the transmission of infrared radiation with a consequent decrease in the signal level. This signal is sensed and amplified in an amplifier A1, after which it is compared with two reference signals from amplifiers Ag and A2 in voltage comparators A1 and A2, which are dimensioned-to form a window detector. The output signal level of the comparators depends on the magnitude of the input signal relative to the light aperture of the window detector and determines the state of a flip-flop circuit F This controls the power supply to a heater 76 for the detector probe and a signal lamp 71 over a heater controller 72. The ice detection cycle is illustrated in FIG. 11.
Medens signallampen 71 giver en simpel isdetektering, kan et mål for probens isdannelseshastighed eller vandindholdet opnås på følgende måde« I fig.While the signal lamp 71 provides a simple ice detection, a measure of the ice formation rate of the probe or the water content can be obtained in the following manner.
11 repræsenterer et punkt a begyndelsen af isdannelsen og strålebundtafskæringen. Mellem punkter b og c behandles udgangssignalet fra A^ i et puffertrin Ag og differentieres i A^,.hvorved der opnås et med isdannelseshastigheden på proben proportionalt udgangssignal, der aflæses ved hjælp af et passende måleinstrument 73. Under tilbagestilling mellem punkterne c og d isoleres måleinstrumentet 73 af et éksemplerings- og holdeorgan. Måleinstrumentet gengiver derfor udgangssignalet fra differentiatoren A^ i isdannelsesperioden inden for vinduesåbningen mellem punkterne b og c og fastholder den sidst målte værdi under cyklens tilbagestillingsværdi.11 represents a point a the beginning of the ice formation and the jet bottom cut-off. Between points b and c, the output signal from A1 is processed in a buffer stage Ag and differentiated into A2, whereby an output signal proportional to the ice formation rate on the probe is obtained, which is read by means of a suitable measuring instrument 73. During reset between points c and d, the measuring instrument 73 by an sampling and holding means. The measuring instrument therefore reproduces the output signal from the differentiator A1 during the ice formation period within the window opening between points b and c and maintains the last measured value below the reset value of the cycle.
Claims (18)
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA154432 | 1972-10-23 | ||
| CA154,432A CA971652A (en) | 1972-10-23 | 1972-10-23 | Ice detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| DK151544B true DK151544B (en) | 1987-12-14 |
| DK151544C DK151544C (en) | 1988-05-30 |
Family
ID=4094737
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| DK572173A DK151544C (en) | 1972-10-23 | 1973-10-22 | ICE FORMATION DETECTOR |
Country Status (9)
| Country | Link |
|---|---|
| JP (1) | JPS5429915B2 (en) |
| CA (1) | CA971652A (en) |
| DK (1) | DK151544C (en) |
| FR (1) | FR2204301A5 (en) |
| GB (1) | GB1406957A (en) |
| IT (1) | IT996874B (en) |
| NO (1) | NO136568C (en) |
| SE (1) | SE394526B (en) |
| SU (1) | SU572195A3 (en) |
Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS54109600U (en) * | 1978-01-19 | 1979-08-01 | ||
| JPS57173778A (en) * | 1981-04-20 | 1982-10-26 | Sharp Corp | Frost sensor |
| JPS57173779A (en) * | 1981-04-20 | 1982-10-26 | Sharp Corp | Frost sensor |
| JPS5899403U (en) * | 1981-12-28 | 1983-07-06 | スカイアルミニウム株式会社 | metal panel fasteners |
| US5416476A (en) * | 1991-11-29 | 1995-05-16 | Rendon; Edward | Method and system for detecting potential icy conditions on roads |
| GB2283315A (en) * | 1993-10-30 | 1995-05-03 | Penny & Giles Avionic Systems | Ice detector |
| US5796344A (en) * | 1995-03-21 | 1998-08-18 | Sprague Controls, Inc. | Imminent icing condition enunciator |
| US6166657A (en) * | 1995-03-21 | 2000-12-26 | Commercial Vehicle Systems, Inc. | Imminent icing condition enunciator |
| US6206299B1 (en) | 1998-04-17 | 2001-03-27 | Commercial Vehicle Systems, Inc. | Traction enhancing deployment system |
| EP2066565B1 (en) | 2006-09-25 | 2010-11-24 | Rosemount Aerospace Inc. | Detecting ice particles |
| CN112498699B (en) * | 2020-12-11 | 2024-05-24 | 武汉航空仪表有限责任公司 | Icing detector based on electric heating principle |
| CN114194399A (en) * | 2021-12-10 | 2022-03-18 | 武汉航空仪表有限责任公司 | Icing sensor based on short wave infrared type |
| CN117906900B (en) * | 2024-02-22 | 2024-05-14 | 中国空气动力研究与发展中心低速空气动力研究所 | Method and device for acquiring residual ice of rotary cap cover in icing wind tunnel test |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH213362A (en) * | 1940-04-03 | 1941-01-31 | Spillmann Werner | Device on aircraft to indicate the risk of icing. |
| US2816233A (en) * | 1954-01-28 | 1957-12-10 | Electronics Corp America | Ice detector |
| US3276254A (en) * | 1963-10-11 | 1966-10-04 | Rosemount Eng Co Ltd | Ice detection apparatus |
| DE2159731A1 (en) * | 1970-12-05 | 1972-06-29 | Rotax Ltd | Ice detector |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3268883A (en) * | 1964-03-04 | 1966-08-23 | Alfred R Puccinelli | Ice detector means |
| US3628028A (en) * | 1968-03-01 | 1971-12-14 | Honeywell Inc | Window cleaning apparatus for photometric instruments |
| US3621714A (en) * | 1969-05-13 | 1971-11-23 | Alfred R Puccinelli | Ice detector means |
-
1972
- 1972-10-23 CA CA154,432A patent/CA971652A/en not_active Expired
-
1973
- 1973-09-25 SE SE7313022A patent/SE394526B/en unknown
- 1973-10-10 GB GB4731373A patent/GB1406957A/en not_active Expired
- 1973-10-19 SU SU7301975925A patent/SU572195A3/en active
- 1973-10-22 NO NO407873A patent/NO136568C/en unknown
- 1973-10-22 DK DK572173A patent/DK151544C/en not_active IP Right Cessation
- 1973-10-22 FR FR7337628A patent/FR2204301A5/fr not_active Expired
- 1973-10-23 JP JP11937173A patent/JPS5429915B2/ja not_active Expired
- 1973-10-23 IT IT7011873A patent/IT996874B/en active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH213362A (en) * | 1940-04-03 | 1941-01-31 | Spillmann Werner | Device on aircraft to indicate the risk of icing. |
| US2816233A (en) * | 1954-01-28 | 1957-12-10 | Electronics Corp America | Ice detector |
| US3276254A (en) * | 1963-10-11 | 1966-10-04 | Rosemount Eng Co Ltd | Ice detection apparatus |
| DE2159731A1 (en) * | 1970-12-05 | 1972-06-29 | Rotax Ltd | Ice detector |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5429915B2 (en) | 1979-09-27 |
| GB1406957A (en) | 1975-09-17 |
| SE394526B (en) | 1977-06-27 |
| SU572195A3 (en) | 1977-09-05 |
| IT996874B (en) | 1975-12-10 |
| CA971652A (en) | 1975-07-22 |
| JPS49134386A (en) | 1974-12-24 |
| NO136568C (en) | 1977-09-28 |
| DK151544C (en) | 1988-05-30 |
| DE2353105B2 (en) | 1976-08-26 |
| DE2353105A1 (en) | 1974-05-02 |
| FR2204301A5 (en) | 1974-05-17 |
| NO136568B (en) | 1977-06-20 |
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