System, equipment, and method for generating low-lying fog

Abstract

The present invention concerns systems (001) for generating fog (204) in the context of protective equipment. More specifically, the present invention concerns systems (001) for generating low-lying fog (204). In addition, the present invention concerns fog-generating devices (200) configured to generate and emit fog (204) and comprising a spray device (100) configured to emit a gas (104), spray devices (100) configured to be connected to a fog-generating device (200), and fog-generating methods (204).

Description

2 tenminutes,thedropletsslowlylandonthegroundduetogravity.Itshould benotedthatthesmallerthefogdroplets(optimalcondensationconditions andfewmutualcollisions)thelongertheycontinuefloatingaround. Normally1cm³ofglycolissufficienttofill1m³ofairwithdropletstoobscure objects(converted,1cm³ofglycolcontainsmorethan200billiondroplets5 withadiameterof2μm).Eachdropletoffogwilldistorttheviewofan observeruntilonlyablurremainsduetoitsconvex-concavereflectionand refractionofincidentphotons. Whenthefog-generatingdeviceisusedasasecuritydevice,the capacityatwhichthefogcanbegenerated,aswellasthedensityandthe10 positionofthegeneratedfogisofcrucialimportance.Forexample,inthe caseofaburglary,thefog-generatingdeviceshouldfilltheroomaroundthe intruderwithdensefogwithinafewseconds.Insuchcase,valuablesare immediatelyobscuredfromthesightoftheintruder,whichwilltrytoescape quicklybyleavingtheroom.Whenfogisgeneratedtooslow,thefogistoo15 thinorrisestoohighfromtheground,thethiefmayusetheadditional secondstoquicklygraspvaluablesbeforeleaving. Aproblemwithfoggenerationforsecurityapplicationsviaglycolsis thattheproducedfogrises,resultinginanabout2.5metersthickfogcloud hangingfromtheceiling.Thisisespeciallyaproblemforroomswithhigh20 ceilings,whichisoftenthecaseincommercialpremises,becausealarge partofthefogdoesnothanglowenough.Thisrisingofthefogcloudis causedbythefactthatallthermalenergythatwasabsorbedbythefog- generatingfluidwithintheheatexchangerisreleasedbackintotheambient air(coolingandcondensationheat)uponejectionofthefog.Consequently,25 theairlayerinwhichmostheatisreleasedwillriseandtakewithitupwards thesmalldropletsoffogfloatingaroundinthatlayer. Severalmeasuresarebeingtakenagainstthis.Thefogejectioncan beaimeddirectlyatthegroundinthehopethattheradialcloudoutflow coolsenoughagainstthefloorarea,suchthatthefogwillriseless.However,30 thismeasureresultsinsubstantiallossoffogdropletsandmayleadtoafog cloudwhichisnothighenoughtoobscuretheenvironmentattheeyelevel BE2025 / 5037 3 ofanintruder.Alternatively,bad(partlycondensing)wetfogcanbeejected tocooldownasquicklyaspossible.However,itismorechallengingto obtainsufficientlydensefogwiththismeasure.Yetanotheralternativeisto guidethecondensate(thefog)ofglycolorglyceroloveracoldsurface,e.g. water-ice,CO2-ice(dryice)orcoldfins,tosufficientlycoolthesedroplets,5 suchthatlow-lyingfogisejectedintothesurroundingarea.Inthelatter case,theheattransferfromthewarmdropletstothecoldsurfaceisthrough infraredradiationandconvection,butnotthroughconduction.Namely,ifthe dropletscomeindirectcontactwiththecoldsurface(belowthedewpoint ofglycol),aglycolliquidfilmwillbeimmediatelydepositedonthesurface.10 Thiswillinturnresultinagreasyglycolfilmonthecoolingsurfacesanda reducedfogejectionduetothelossofdroplets. Below,severalexamplesfromthepriorartareprovidedforcooling thefog.US5711481Aisconcernedwithgeneratingspecialeffectsfogsuch aslow / ground-huggingfog.Itprovidesaprocessandanapparatusfor15 generatingfogbymixinghotsteamandambientairinachambertoobtain warmhumidair,andbyaddingacryogenicfluidtothechamberwithwarm humidairtocoolthehumidairstreamandturntheentiregasmixtureinto fog.US2007012064A1isconcernedwithgeneratinglow-lyingfogfor entertainmentevents.Itprovidesaventuriapparatusforgeneratingcoldfog20 bycoolingthefoginaflashfreezechamber,afterithasbeengenerated andbeforeithasbeenejectedintotheenvironment.Theflashfreeze chambermaybecooledbyusingdryice.RoscoColdFlowfogchillerisan accessorywhichcanbeconnectedtostandardfogmachinestoconvertthe producedfogintodenselow-lyingfog.Thefogchillercomprisesan25 aluminumcoolingchamber,andconvertsliquidcarbondioxidetodryice, whichinturncoolsanaluminumchamber.Themainlimitationofallthe aboveapproachesisthathighamountsoffogwillbelostduetodirect contactofthecooledfogwithchamber,suchthatsufficientdensityofthe fogforsecuritydevicescannotbeascertained.30 Tosummarize,allofthepreviouslydescribedmeasurestogenerate low-lyingfoginevitablyalsoreducethedensityandthequalityofthefog. BE2025 / 5037 4 However,toobscurevaluablesfromthesightofanintruder,itisimperative thatthesecurityfog-generatingdevicesproducefogthatnotonlystayslow butalsoremainsverydense. SUMMARYOFTHEINVENTION5 Theinventorhassurprisinglyfoundthatsprayingagasaboveafog notonlypreventsthefogfromrising,butalsofurtherincreasesthedensity ofthefogandresultsinamorerapidspreadofthefogwithintheroom.Itis indeedanaimofthepresentinventiontoprovideasystem,devicesanda methodforgeneratingafogthatstaylowandremainsdense.10 Itisaparticularaspectoftheinventiontoprovideasystemfor generatingfog,comprisingafog-generatingdevicewhichisconfiguredto generateandtoejectafog,andasprayingdevicewhichisconfiguredto ejectagas,characterizedinthatthesystemisconfiguredsuchthatthegas ejectedbythesprayingdeviceisejectedabovethefogejectedbythefog-15 generatingdevice.Theflowofejectedgasabovethefogcausesa downwardflowofthefog. Inaparticularembodiment,thegashasadensityhigherthanthe densityofair.Inapreferredparticularembodiment,thegashasadensity higherthan1.2kg / m3,preferablyhigherthan1.5kg / m3,morepreferably20 higherthan1.8kg / m3.Thehigherdensityoftheejectedgascomparedto thedensityofambientaircausesadownwardflowofthegasandtherefore adownwardflowofthefogbelowthegas. Inaparticularembodiment,theejectedgashasatemperaturebelow ambienttemperature,preferablyatemperatureof0°Corless.Inparticular,25 thesprayingdeviceisconfiguredtoejectthegasatatemperaturebelow ambienttemperature,preferablyatatemperatureof0°Corless.Thecooler temperatureofthegascomparedtothetemperatureofambientaircauses adownwardflowofthegasandthereforeadownwardflowofthefogbelow thegas.30 Inapreferredparticularembodiment,thesprayingdeviceis configuredtoejectagaswithadensityhigherthanthedensityofair,ata BE2025 / 5037 5 temperaturebelowambienttemperature.Ejectingaheavygaswhichisalso cooledabovethefogfurtherincreasesthedownwardflowofthegasand thefogbelowit. Inaparticularembodiment,thesystemisconfiguredtoejectamass ofthegaswiththesprayingdevicewhichislargerthanthemassoffog5 ejectedbythefog-generatingdevice.Inapreferredparticularembodiment, thesystemisconfiguredtoejectamassofthegaswiththesprayingdevice whichisatleast1.1,preferablyatleast1.2,morepreferablyatleast1.3, evenmorepreferablyatleast1.4,and / oratmost1.9,preferablyatmost1.8, morepreferablyatmost1.7,evenmorepreferablyatmost1.6timesthe10 massoffogejectedbythefog-generatingdevice.Usingamassofthegas whichislargerthanthemassoffogfacilitatesafasterandmoreefficient downwardflow.Inaparticularembodiment,thegasisselectedfromthegroup consistingofCO2,HFC,N2O,HFOandXegas,preferablyCO2gas.Itisan15 advantagethatCO2,HFC,N2O,andHFOgasesareliquidgasesunder pressure.ItisanadvantagethatXegashasahighdensity.TheCO2gasis favoredoverothergases,becauseitisnotflammable,andhasfavorable physicalcharacteristics,lowtoxicity,andanacceptableglobalwarming potentialvalue.TheCO2gascanconvenientlybestoredinaliquidstate20 underpressureandejectedatatemperaturebelowambienttemperature, i.e.asacoldgas.TheCO2gasisalsoaheavygas,andissignificantly cheaperthanforexampleXegas.Inaparticularembodiment,thesprayingdevicecomprisesa reservoircomprisingthegas,preferablyapressurizedreservoircomprising25 thegascompressedtoaliquidstate;agasoutletopeningviawhichthegas inthereservoirisejectedoutofthesprayingdevice;andavalvebetween thereservoirandthegasoutletopening,whereinthevalvehasanopen stateandclosedstate,whereinintheclosedstatethevalvepreventsthe gastoflowfromthereservoirtothegasoutletopening,andwhereininthe30 openstatethevalveallowsthegastoflowfromthereservoirtothegas outletopening.Inafurtherparticularembodiment,thegasoutletopeningof BE2025 / 5037 6 thesprayingdevicecomprisesanozzleoranaerodynamicpipe.This facilitatesgooddistributionofthegasabovethefog. Inaparticularembodiment,thefog-generatingdevicecomprisesa reservoircomprisingafog-generatingfluid;aheatexchanger;andafog outletopening.Inafurtherparticularembodiment,thefogoutletopeningof5 thefog-generatingdevicecomprisesanozzle.Inaparticularembodiment, thefog-generatingfluidcomprisesapolyol;preferablyaglycol;more preferablyatleastoneofdipropyleneglycolandtriethyleneglycol.The presenceofdipropyleneortriethyleneglycolispreferredoverthelower glycolssuchasforexamplediethyleneglycol,astheformerhardlyreacts10 withwateratthetemperaturesremaininginthedevice,whereasthelatter isreactivewithwatertoproducecorrosivecompounds.Suchlowerglycols arehowevernotexcludedfrombeingused. Inaparticularembodiment,thesprayingdeviceandthefog- generatingdeviceareintegratedwitheachotherorfixedtoeachother.In15 anotherparticularembodiment,thesprayingdeviceisconfiguredtobe releasablyconnectedtothefog-generatingdevice.Inapreferredparticularembodiment,thesystemforgeneratingfog comprises:afog-generatingdevice,whichisconfiguredtogeneratea glycol-comprisingfogfromaglycol-comprisingfog-generatingfluidby20 meansofaheatexchanger,andtoejecttheglycol-comprisingfog,anda sprayingdevicewhichisconfiguredtoejectCO2gas,characterizedinthat thesystemisconfiguredsuchthattheCO2gasejectedbythespraying deviceisejectedabovetheglycol-comprisingfogejectedbythefog- generatingdevice.25 Itisafurtheraspectoftheinventiontoprovideasprayingdevice whichisconfiguredtobereleasablyconnectedtoafog-generatingdevice configuredtogenerateandtoejectafog,whereinthesprayingdeviceis configuredtoejectagas,characterizedinthatthesprayingdeviceis30 configuredsuchthat,whenthesprayingdeviceisconnectedtothefog- BE2025 / 5037 7 generatingdevice,thegasejectedbythesprayingdeviceisejectedabove thefogejectedbythefog-generatingdevice. Inparticularembodiments,thesprayingdeviceisasdescribed above.Inaparticularembodiment,thesprayingdeviceisconfiguredtobe5 releasablyconnectedtoafog-generatingdevicewhichisconfiguredto generateaglycol-comprisingfogfromaglycol-comprisingfog-generating fluidbymeansofaheatexchanger,andtoejecttheglycol-comprisingfog, whereinthesprayingdeviceisconfiguredtoejectCO2gas. 10 Itisafurtheraspectoftheinventiontoprovideafog-generating devicewhichisconfiguredtogenerateandtoejectafog,comprisingan integratedsprayingdevicewhichisconfiguredtoejectagas,characterized inthatthefog-generatingdeviceisconfiguredsuchthatthegasejectedby theintegratedsprayingdeviceisejectedabovethefogejectedbythefog-15 generatingdevice. Inparticularembodiments,thefog-generatingdeviceisasdescribed above. Inparticularembodiments,theintegratedsprayingdeviceisa sprayingdeviceasdescribedabove.20 Inapreferredparticularembodiment,theintegratedsprayingdevice isconfiguredtoejectCO2gas,andthefog-generatingdeviceisconfigured togenerateaglycol-comprisingfogfromaglycol-comprisingfog-generating fluidbymeansofaheatexchanger,andtoejecttheglycol-comprisingfog. 25 Itisafurtheraspectoftheinventiontoprovideamethodfor generatingfog,whereinthemethodcomprisesthestepsof:generatingand ejectingafog,preferablybymeansofafog-generatingdevice;andejecting agas,preferablybymeansofasprayingdevice,characterizedinthatthe gasisejectedabovethefog.30 Inaparticularembodimentthefogisaglycol-comprisingcomprising fog. BE2025 / 5037 8 InaparticularembodimentthegasisCO2gas. BRIEFDESCRIPTIONOFTHEDRAWINGS FIG.1illustratesasystemforgeneratingfogaccordingtoan embodimentofthepresentinvention.5 Thedrawingsareonlyschematicandarenon-limiting.Inthe drawings,thesizeofsomeoftheelementsmaybeexaggeratedandnot drawnonscaleforillustrativepurposes.Thedimensionsandtherelative dimensionsdonotcorrespondtoactualreductionstopracticeofthe10 invention. DETAILEDDESCRIPTIONOFTHEINVENTION Thepresentinventionrelatestoasystemforgeneratingfog, comprisingafog-generatingdeviceandasprayingdevice;aspraying15 deviceconfiguredtobeconnectedtoafog-generatingdevice;afog- generatingdevicecomprisinganintegratedsprayingdevice;andamethod forgeneratingfogcomprisingthestepsofgeneratingandejectingafog, andejectingagas. Particularandpreferredaspectsoftheinventionaresetoutinthe20 accompanyingindependentanddependentclaims.Featuresfromthe dependentclaimsmaybecombinedwithfeaturesoftheindependentclaims andwithfeaturesofotherdependentclaimsasappropriateandnotmerely asexplicitlysetoutintheclaims. Theseandotheraspectsoftheinventionwillbeapparentfromand25 elucidatedwithreferencetotheembodiment(s)describedhereinbeforeand hereinafter.Thepresentinventionwillbedescribedwithrespecttoparticular embodimentsandwithreferencetocertaindrawingsbuttheinventionisnot limitedtheretobutonlybytheclaims.30 BE2025 / 5037 9 Thetermsupward,downward,horizontal,above,below,top,bottom, andthelikeinthedescriptionandtheclaimsareusedfordescriptive purposesandnotnecessarilyfordescribingrelativepositions.Itistobe understoodthatthetermssousedareinterchangeableunderappropriate circumstancesandthattheembodimentsoftheinventiondescribedherein5 arecapableofoperationinotherorientationsthandescribedorillustrated herein. Referencethroughoutthisspecificationto"anembodiment"means thataparticularfeature,structureorcharacteristicdescribedinconnection withtheembodimentisincludedinatleastoneembodimentofthepresent10 invention.Thus,appearancesofthephrase"inanembodiment"invarious placesthroughoutthisspecificationarenotnecessarilyallreferringtothe sameembodiment,butmay.Furthermore,theparticularfeatures,structures orcharacteristicsmaybecombinedinanysuitablemanner,aswouldbe apparenttooneofordinaryskillintheartfromthisdisclosure,inoneor15 moreembodiments. Similarly,itshouldbeappreciatedthatinthedescriptionofexemplary embodimentsoftheinvention,variousfeaturesoftheinventionare sometimesgroupedtogetherinasingleembodiment,figure,ordescription thereofforthepurposeofstreamliningthedisclosureandaidinginthe20 understandingofoneormoreofthevariousinventiveaspects.Thismethod ofdisclosure,however,isnottobeinterpretedasreflectinganintentionthat theclaimedinventionrequiresmorefeaturesthanareexpresslyrecitedin eachclaim.Rather,asthefollowingclaimsreflect,inventiveaspectsliein lessthanallfeaturesofasingleforegoingdisclosedembodiment.Thus,the25 claimsfollowingthedetaileddescriptionareherebyexpresslyincorporated intothisdetaileddescription,witheachclaimstandingonitsownasa separateembodimentofthisinvention.Furthermore,whilesomeembodimentsdescribedhereininclude somebutnototherfeaturesincludedinotherembodiments,combinations30 offeaturesofdifferentembodimentsaremeanttobewithinthescopeofthe invention,andformdifferentembodiments,aswouldbeunderstoodby BE2025 / 5037 10 thoseintheart.Forexample,inthefollowingclaims,anyoftheclaimed embodimentscanbeusedinanycombination. Inthedescriptionprovidedherein,numerousspecificdetailsareset forth.However,itisunderstoodthatembodimentsoftheinventionmaybe practicedwithoutthesespecificdetails.Inotherinstances,well-known5 methods,structuresandtechniqueshavenotbeenshownindetailinorder nottoobscureanunderstandingofthisdescription. Definitions Asusedhereintheterm"gas"referstoamaterialwhichisingaseous stateatambienttemperature.Thetermgasislikewiseusedforsuch10 materialinaliquidstate,forexamplewhenthegasiscompressedtoits liquidstateandstoredinapressurizedreservoir.Theterm“gas”islikewise usedforsuchmaterialinasolidstate,forexamplewhenthegasiscooled toitssolidstate,suchasdryiceisCO2gasinasolidstate. Asusedhereintheterm"fog"referstoliquiddropletssuspendedin15 theair.Inparticular,fogasusedhereinreducesvisibilitytolessthan5 meter,moreinparticularlessthan2meter.Suchfogcanbeusedtoobscure e.g.valuablesfromintruders. Asusedhereintheterm"afog-generatingfluid"referstoanyfluid, suchasageloraliquid,orcombinationsoffluids,thatcanbevaporized20 whenfedthroughaheatexchangerofthefog-generatingdevice.When exitingtheheatexchangerintotheatmosphericpressureandnormal ambienttemperaturethevaporcondensesintotinyliquiddroplets suspendedintheairasaerosol,withtheformationofavisiblecloudoffog. Forthepurposeofthecurrentinvention,thefog-generatingfluidis25 preferablyapolyol-containingfog-generatingfluid,meaningthatthefog- generatingfluidcomprisesapolyol,suchasglycol,andoptionallywater. Morepreferableistheuseofafog-generatingfluidcomprisingapolyoland water.Itistobenotedthate.g.oil-basedsmokegeneratorsarenot preferableforindoorpurposes,astheyimpactthehealthofhabitantsand30 intrudersandleavegreasytraceresiduesafterthefloatingparticleshave beencleared.Therefore,thefog(andhencethefog-generatingfluid)as BE2025 / 5037 11 usedherein,does,forindooruse,preferablynotcorrespondtothesmoke generatedusingoil-basedsmokegenerators. Asusedhereintheterm"expellingfog","ejectingfog"orsimilarterms byafog-generatingdevice,generallyreferstotheprocesswhereinafog- generatingsubstance(alsoreferredtoasafog-generatingfluid)isdriven5 throughaheat-exchanger,withtheconversionofsaidfog-generating substanceintothevaporphasethatisexpelledorejectedattheexit(fog outletopening)ofsaidheatexchanger. Systemforgeneratingfog Inafirstaspect,thepresentinventionrelatestoasystemfor10 generatingfog. Bywayofillustrationandnotlimitedthereto,embodimentsofthe systemforgeneratingfogofthepresentinvention,andstandardand optionalcomponentsofthesystemforgeneratingfog,aredepictedinFIG. 1.Thesystem(001)forgeneratingfogaccordingtothecurrentinvention15 comprisesoneormorefog-generatingdevices(200)whichareconfigured togenerateandtoejectafog(204),andoneormoresprayingdevices(100) whichareconfiguredtoejectagas(104). Inapreferredembodiment,thesystem(001)isconfiguredsuchthat thegas(104)ejectedbythesprayingdevice(100)isejectedabovethefog20 (204)ejectedbythefog-generatingdevice(200).Preferably,thegas(104) hasadensityhigherthanthedensityofair(1.2kg / m3).Gaswithadensity higherthanthedensityofairisalsoreferredtoas“heavygas”,contraryto gaswithadensitylowerthanthedensityofair,whichisalsoreferredtoas “lightgas”.Preferably,thegas(104)hasadensityhigherthan1.2kg / m3,25 preferablyhigherthan1.5kg / m3,morepreferablyhigherthan1.8kg / m3. Ejectionofaheavygasabovethefogresultsindownwardflowofthegas andtakesthefogclouddownwardswithittowardsthegroundorfloor(300). Preferably,thesprayingdevice(100)isconfiguredtoejectthegas(104)at atemperaturebelowambienttemperature,preferablyatatemperatureof030 °Corless.Gaswithatemperaturebelowambienttemperatureisalso referredtoas“coldgas”.Ejectionofacoldgasabovethefogcoolsthe BE2025 / 5037 12 ambientairsurroundingthefogcloud,andthuspreventsthefogcloudfrom rising.Mostpreferably,thesprayingdevice(100)isconfiguredtoejectthe gas(104)atatemperaturebelowambienttemperature,whereinthegas (104)hasadensityhigherthanthedensityofair.Thecombinedeffectof heavygaswhichisalsocoldresultsinamorerapiddownwardflowofthe5 fog.Inaddition,downwardflowofthefogincreasesthedensityofthefog andspeedsupthespreadofthefog,asthespacebetweenthegroundand thetopofthefogcloudbecomesmorelimited.Typicalcoolinggasesknown tothepersonskilledintheartmaybeejectedabovethefog.Thegas(104) ispreferablyselectedfromthegroupconsistingofcarbondioxide(CO2)gas,10 hydrofluorocarbon(HFC)gas,nitrousoxide(N2O)gas,hydrofluoroolefin (HFO)gasandxenon(Xe)gas.PreferredHFCgasisapartlyfluorinated HFCgas,suchasdifluoromethane,trifluoroethane,CH3-CF3,1,1,1,2- tetrafluoroethane,pentafluoroethaneCHF2-CF3,1,1,1,2,3,3,3- heptafluoropropaneoramixtureoftwoormoreofthesecompounds.15 Preferably,thegas(104)isaliquidgasunderpressure.Mostpreferablythe gasisCO2gas.TheCO2gasisfavoredoverothergases,becauseitisnot flammable,andhasfavorablephysicalcharacteristics,lowtoxicity,andan acceptableglobalwarmingpotentialvalue.TheCO2gascanconveniently bestoredinaliquidstateunderpressureandejectedatatemperature20 belowambienttemperature,i.e.asacoldgas.TheCO2gasisalsoaheavy gas,andissignificantlycheaperthanforexampleXegas. Inapreferredembodiment,thesystem(001)isconfiguredtoeject anamountofthegas(104)withthesprayingdevice(100)whichisinmass largerthantheamountoffog(204)ejectedbythefog-generatingdevice25 (200).Inparticular,thesystemisconfiguredtoejectanamountofthegas (104)withthesprayingdevice(100)whichisinmassatleast1.1,preferably atleast1.2,morepreferablyatleast1.3,evenmorepreferablyatleast1.4, and / oratmost1.9,preferablyatmost1.8,morepreferablyatmost1.7,even morepreferablyatmost1.6timestheamountoffog(204)ejectedbythe30 fog-generatingdevice(200). BE2025 / 5037 13 Inanalternativeembodiment,thesystemisconfiguredsuchthata heavygasisejectedbyafirstsprayingdeviceabovethefogejectedbythe fog-generatingdevice,andalightgasisejectedbyasecondspraying devicebelowthefogejectedbythefog-generatingdevice.Thismayfurther increasethedensityofthefogcloudandenablemoreprecisepositioning5 ofthefogcloudinthespacebetweentheground / floor(300)andtheceiling (400). Sprayingdevice Thesprayingdevice(100)typicallycomprisesareservoir(101) comprisingthegas;agasoutletopening(103)viawhichthegasinthe10 reservoirisejectedoutofthesprayingdevice;andavalve(102)between thereservoir(101)andthegasoutletopening(103). Inapreferredembodiment,thesprayingdevice(100)comprisesa pressurizedreservoir(101)comprisinggascompressedtoaliquidstate.In afurtherpreferredembodiment,thesprayingdevicecomprisesa15 pressurizedreservoircomprisingCO2gascompressedtoaliquidstate. Thus,preferably,thesprayingdeviceisaCO2sprayingdevice.Inan alternativeembodiment,thesprayingdevice(100)comprisesapressurized reservoir(101)comprisinggasinagasstate,suchasXegas.Typically,the reservoir(101),preferablythepressurizedreservoir,hasavolumeofat20 least0.5L,preferablyatleast0.7L,morepreferablyatleast1L,and / orat most5L,preferablyatmost3L,morepreferablyatmost2L. Thegasoutletopening(103)maycompriseapipe,suchasan aerodynamicpipe(e.g.aventouripipe,aBernouillipipe,asteamejector); anozzle,suchasadeLavalnozzle,aspiralnozzle,aslitnozzle;orapipe25 andanozzle.Foranozzle,theshapeandtheorientationofthenozzle determineswherethemostthermalenergywillbeabsorbedbyacoldgas, suchascoldCO2gas.Inapreferredembodiment,thevalve(102)hasanopenstateanda closedstate,whereinintheclosedstatethevalvepreventsthegastoflow30 fromthereservoir(101)tothegasoutletopening(103),andwhereininthe openstatethevalveallowsthegastoflowfromthereservoir(101)tothe BE2025 / 5037 14 gasoutletopening(103).Preferably,thevalve(102)isanormallyclosed valve.Preferably,thevalve(102)isanelectromagneticvalve. Inapreferredembodiment,thesprayingdevice(100)isconfigured tobeconnectabletooneormorefog-generatingdevices(200).The connectionbetweenthesprayingdevice(100)andtheoneormorefog-5 generatingdevices(200)enablesactuationofthesprayingdevice(100) uponactuationofthefog-generatingdevices(200).Hereto,thespraying device(100)maybeconnecteddirectlytotheoneormorefog-generating devices(200),suchthatthesprayingdevice(100)isactuatedupon actuationofthefog-generatingdevices(200).Alternatively,thespraying10 device(100)andtheoneormorefog-generatingdevices(200)maybe connectedtoathirddevice,suchasanalarmdevice,suchthatthespraying device(100)andtheoneormorefog-generatingdevices(200)areactuated uponactuationofthesaidthirddevice.Theactuationofthesprayingdevice (100)mayoccursimultaneouslywiththeactuationoftheoneormorefog-15 generatingdevices(200),orimmediatelyaftertheactuationoftheoneor morefog-generatingdevices(200).Theconnectionbetweenthespraying device(100)andthefog-generatingdevice(200)orthethirddevice,such asanalarmdevice,maybeanysuitableconnectionknowntoaperson skilledintheart.Forexample,theconnectionmaybeawiredconnection20 (e.g.cable)orawirelessconnection(e.g.WiFiorBluetooth). Inapreferredembodiment,thesprayingdevice(100)isconfigured toejectagas(104)simultaneouslywithafog(204)ejectedbytheoneor morefog-generatingdevices(200).Inanotherpreferredembodiment,the sprayingdevice(100)isconfiguredtoejectagas(104)immediatelyaftera25 fog(204)ejectedbytheoneormorefog-generatingdevices(200).Asused herein,theterm“immediatelyafter”referstoanytimeintervalbelow10s, preferablybelow5s,morepreferablybelow1s. Fog-generatingdevice WithreferencetoFIG.1,thefog-generatingdevice(200)typically30 comprisesareservoircomprisingafog-generatingfluid;aheatexchanger; andafogoutletopening(203).Typically,thereservoirisconnectedtoa BE2025 / 5037 15 heatexchanger,whereintheheatexchangerisconfiguredforheatingand therebyevaporatingthefog-generatingfluidandcomprisesanoutlet openingforexpellingtheevaporatedfog-generatingfluidunderpressure outofthefog-generatingdevice.Thustheevaporatedfog-generatingfluid, generatedwithintheheatexchangerisexpelledoutofthefog-generating5 deviceintotheenvironmentwhereitcondensesquicklyintoafog. Thereservoirofthefog-generatingdeviceispreferablyapressurized reservoir.Thereservoirmaybeconnectedtotheheatexchangerbya varietyofconnectingelements,e.g.atubeorahollowneedle,anaperture, oraslitinamembrane.Typically,theconnectionofthereservoirtotheheat10 exchangerisafluidconnection.Thereservoirtypicallycomprisesavalve, whichinaclosedpositionpreventsthefog-generatingfluidfromflowingout ofthereservoirtotheheatexchanger.Thevalvemaybeanon-and-offvalve oraone-shotvalve.Thestandardandoptionalfeaturesofsuchanon-and- offvalvearedescribedinthepatentapplication,particularlyintheclaimsof15 patentapplicationWO03001140A1,whichisherebyincorporatedby reference.Thestandardandoptionalfeaturesofanexemplaryone-shot valvearedescribedinthepatentapplication,particularlyintheclaimsof patentapplicationEP3017268B1,whichisherebyincorporatedby reference.Thereservoirmaybecomprisedwithinaremovablehousing,20 whichhousingcanberemovablyconnectedtotheheatexchangerofthe fog-generatingdevice.Theconnectionoftheremovablehousingtotheheat exchangercanbeachievedthroughacoupling,inparticularacouplingin theconnectingelementbetweenthehousingandtheheatexchanger.An exampleofsuchcouplingisdepictedinFig.1ofWO03001140A1,whichis25 herebyincorporatedbyreference. Thefog-generatingfluidpreferablycomprisesapolyol,suchasa glycol,andwater.Suitable(oftenwater-based)polyol-containingfluidsare availabletotheskilledperson.Inapreferredembodiment,thefog- generatingfluidcomprisesapolyol,suchasglycol,inanamountof50to30 90vol.%,preferablyinanamountof70to90vol.%..Inafurtherpreferred embodiment,thefog-generatingfluidcomprisesaglycol(aliphaticdiol).In BE2025 / 5037 16 afurtherpreferredembodiment,thefog-generatingfluidcomprisesatleast oneofdipropyleneglycolandtriethyleneglycol.Mostpreferably,thefog- generatingfluidcomprisesdipropyleneglycolandtriethyleneglycol.The presenceofdipropyleneortriethyleneglycolispreferredoverthelower glycolssuchasforexamplediethyleneglycol,astheformerhardlyreacts5 withwateratthetemperaturesremaininginthedevice,whereasthelatter isreactivewithwatertoproducecorrosivecompounds.Suchlowerglycols arehowevernotexcludedfrombeingused.Thefog-generatingfluid preferablycompriseswaterinanamountof10to30vol.%.Inapreferred embodiment,thefog-generatingfluidcomprisesglycolinanamountof7010 to90vol.%,andwaterinanamountof10to30vol.%.Inafurtherpreferred embodiment,thefog-generatingfluidcomprisesatleastoneofdipropylene glycolandtriethyleneglycolinanamountof70to90vol.%,andwaterin anamountof10to30vol.%.Inafurtherpreferredembodiment,thefog- generatingfluidcomprisesdipropyleneglycolandtriethyleneglycolinan15 amountof70to90vol.%,andwaterinanamountof10to30vol.%.The fog-generatingfluidmayfurthercompriseanalcohol,suchasethanol.The fog-generatingfluidmayfurthercompriseadditionalcompounds,suchas menthol,lachrymators,etc.Thefog-generatingdevicetypicallyfurthercomprisesapropellant.20 Thepropellantisasubstance,acompositionoramixture,whichcan generateoverpressuretodrivethefog-generatingfluidwithinafog- generatingdevice,inparticularfromthereservoirtotheheatexchangerof thefog-generatingdevice.Thepropellantmaybeamixtureofoneormore partlyhalogenatedhydrocarbons,acompressedgas(e.g.ambientair;inert25 gas,suchasnitrogen;noblegas,suchashelium,neon,orargon;mixture ofnoblegasses;mixtureofinertandnoblegasses),adissolvedgas(e.g. nitrousoxide).Inanalternativeparticularembodiment,thepropellantis separatedfromthefog-generatingfluidbyamovablewall.Anexampleofa fog-generatingdevicewithamovablewallisdescribedinEP2860486A1.30 Thefogoutletopening(203)maycompriseapipe,suchasan aerodynamicpipe;anozzle,suchasadeLavalnozzle,aspiralnozzle,a BE2025 / 5037 17 slitnozzle;oracombinationofapipeandanozzle.Preferably,thefogoutlet opening(203)comprisesanozzleoranaerodynamicpipe.Inaparticular embodiment,thefogoutletopeningcomprisesanozzlefordispersingfog- generatingfluidthathasbeenvaporizedbyheat,thenozzlecomprising:at leastoneinletforthevaporizedfogliquid,afirstsetofoutletslocatedinthe5 centralpartoftheoutersurfaceofthenozzle,andasecondsetofoutlets situatedinaperipheralpartoftheoutersurface;whereintheflowrate throughthefirstsetofoutletsislowerthantheflowratethroughthesecond setofoutlets.Thestandardandoptionalcomponentsofthelatternozzle aredescribedandillustratedinEP3263223A1,whichisherebyincorporated10 byreference. Thesystem(001)forgeneratingfogcomprisesoneormorespraying devices(100),asdescribedherein,andoneormorefog-generatingdevices (200),asdescribedherein.15 Inaparticularembodiment,theoneormoresprayingdevices(100) areintegratedwiththeoneormorefog-generatingdevices(200).Inan alternativeparticularembodiment,theoneormoresprayingdevices(100) arefixedtotheoneormorefog-generatingdevices(200).Inanother alternativeparticularembodiment,theoneormoresprayingdevices(100)20 areconfiguredtobereleasablyconnectedtotheoneormorefog-generating devices(200). Inapreferredembodiment,thesystem(001)forgeneratingfog comprisesoneormoresprayingdevices(100)eachcomprisingagasoutlet opening(103)andoneormorefog-generatingdevices(200)each25 comprisingafogoutletopening(203),whereinthegasoutletopenings(103) arepositionedabovethefogoutletopenings(203)suchthatthegas(104) ejectedbytheoneormoresprayingdevices(100)isejectedabovethefog (204)ejectedbytheoneormorefog-generatingdevices(200).Inapreferredembodiment,thesystem(001)forgeneratingfog30 comprisesoneormorefog-generatingdevices(200),whichareconfigured togenerateaglycol-comprisingfog(204)fromaglycol-comprisingfog- BE2025 / 5037 18 generatingfluidbymeansofaheatexchanger,andtoejecttheglycol- comprisingfog,andoneormoresprayingdevices(100)whichare configuredtoejectCO2gas(104),characterizedinthatthesystemis configuredsuchthattheCO2gasejectedbythesprayingdevicesisejected abovetheglycol-comprisingfogejectedbythefog-generatingdevices.5 Inapreferredembodiment,thesystem(001)forgeneratingfogis configuredtoejectagas(104)ejectedbytheoneormoresprayingdevices (100)simultaneouslywithafog(204)ejectedbytheoneormorefog- generatingdevices(200).Inanotherpreferredembodiment,thesystem (001)forgeneratingfogisconfiguredtoejectagas(104)ejectedbytheone10 ormoresprayingdevices(100)immediatelyafterafog(204)ejectedbythe oneormorefog-generatingdevices(200).Asusedherein,theterm “immediatelyafter”referstoanytimeintervalbelow10s,preferablybelow 5s,morepreferablybelow1s. Inapreferredembodiment,thesystem(001)forgeneratingfog15 comprisesonesprayingdevice(100)andonefog-generatingdevice(200). Sprayingdevice Inafurtheraspect,thepresentinventionrelatestoasprayingdevice (100),asdescribedintheapplication. Inapreferredembodiment,thesprayingdevice(100)isconfigured20 tobereleasablyconnectedtooneormorefog-generatingdevices(200) configuredtogenerateandtoejectafog(204),whereinthesprayingdevice (100)isconfiguredtoejectagas(104),characterizedinthatthespraying device(100)isconfiguredsuchthat,whenthesprayingdevice(100)is connectedtotheoneormorefog-generatingdevices(200),thegas(104)25 ejectedbythesprayingdevice(100)isejectedabovethefog(204)ejected bythefog-generatingdevices(200).Inafurtherpreferredembodiment,the sprayingdevice(100)isconfiguredtobereleasablyconnectedtooneor morefog-generatingdevices(200)whichareconfiguredtogeneratea glycol-comprisingfog(204)fromaglycol-comprisingfog-generatingfluidby30 meansofaheatexchanger,andtoejecttheglycol-comprisingfog,wherein thesprayingdevice(100)isconfiguredtoejectagas(104).Inafurther BE2025 / 5037 19 preferredembodiment,thesprayingdevice(100)isconfiguredtobe releasablyconnectedtooneormorefog-generatingdevices(200)which areconfiguredtogenerateaglycol-comprisingfog(204)fromaglycol- comprisingfog-generatingfluidbymeansofaheatexchanger,andtoeject theglycol-comprisingfog,whereinthesprayingdevice(100)isconfigured5 toejectCO2gas(104). Fog-generatingdevice Inafurtheraspect,thepresentinventionrelatestoafog-generating device(200),asdescribedintheapplication.Inapreferredembodiment,thefog-generatingdevice(200)is10 configuredtogenerateandtoejectafog(204),andcomprisesanintegrated sprayingdevice(100)whichisconfiguredtoejectagas(104),characterized inthatthefog-generatingdevice(200)isconfiguredsuchthatthegas(104) ejectedbytheintegratedsprayingdevice(100)isejectedabovethefog (204)ejectedbythefog-generatingdevice(204).Thestandardandoptional15 characteristicsofthesprayingdevice(100)aredescribedintheapplication. Inafurtherpreferredembodiment,theintegratedsprayingdevice(100)is configuredtoejectagas(104),andthefog-generatingdevice(200)is configuredtogenerateaglycol-comprisingfog(204)fromaglycol- comprisingfog-generatingfluidbymeansofaheatexchanger,andtoeject20 theglycol-comprisingfog.Inafurtherpreferredembodiment,theintegrated sprayingdevice(100)isconfiguredtoejectCO2gas(104),andthefog- generatingdevice(200)isconfiguredtogenerateaglycol-comprisingfog (204)fromaglycol-comprisingfog-generatingfluidbymeansofaheat exchanger,andtoejecttheglycol-comprisingfog.Theintegratedspraying25 device(100)maybeintegratedwithinthehousingofthefog-generating device(200). Methodforgeneratingfog Inafurtheraspect,thepresentinventionrelatestoamethodfor generatingfog,themethodcomprisingthestepsof:30 BE2025 / 5037 20 -generatingandejectingafog,preferablybymeansofafog- generatingdevice;and -ejectingagas,preferablybymeansofasprayingdevice, characterizedinthatthegasisejectedabovethefog. 5 Inapreferredembodiment,themethodcomprisesthestepsof: -generatingandejectingaglycol-comprisingfog,preferablyby meansofafog-generatingdevice;and -ejectingagas,preferablybymeansofasprayingdevice, characterizedinthatthegasisejectedabovetheglycol-comprising10 fog.Inafurtherpreferredembodiment,themethodcomprisesthesteps of: -generatingandejectingaglycol-comprisingfog,preferablyby15 meansofafog-generatingdevice;and -ejectingCO2gas,preferablybymeansofasprayingdevice, characterizedinthattheCO2gasisejectedabovetheglycol- comprisingfog. 20 Inaparticularembodiment,themethodcomprisesthestepsof: -providingasprayingdeviceconfiguredtoejectagasand configuredtobereleasablyconnectedtoafog-generating deviceconfiguredtogenerateandtoejectafog, -connectingthesprayingdevicetothefog-generatingdevice,25 -generatingandejectingthefogbymeansofthefog- generatingdevice -ejectingthegasbymeansofthesprayingdevice, characterizedinthatthegasisejectedabovethefog, whereinpreferablythefogisaglycol-comprisingcomprisingfog,30 whereinpreferablythegasisCO2gas.BE2025 / 5037 21 Inanotherparticularembodiment,themethodcomprisesthesteps of: -providingafog-generatingdeviceconfiguredtogenerateand toejectafog,comprisinganintegratedsprayingdevice configuredtoejectagas,5 -generatingandejectingthefogbymeansofthefog- generatingdevice -ejectingthegasbymeansoftheintegratedsprayingdevice, characterizedinthatthegasisejectedabovethefog, whereinpreferablythefogisaglycol-comprisingcomprisingfog,10 whereinpreferablythegasisCO2gas. Inpreferredembodiments,thegasisejectedsimultaneouslywiththe fog.Inotherpreferredembodiments,thegasisejectedimmediatelyafter thefog.15 Inpreferredembodiments,thefogisgeneratedbyheatingafog- generatingfluidinaheatexchangerofthefog-generatingdevice.In preferredembodiments,thefogisejectedthroughafogoutletopeningof thefog-generatingdevice.Inpreferredembodiments,thegasisejected20 throughagasoutletopeningofthesprayingdevice.EXAMPLES Abetterunderstandingofthepresentinventionmaybeobtained throughthefollowingexampleswhicharesetforthtoillustrate,butarenot25 tobeconstruedaslimitingthescopeofthepresentinvention. Example1 Inthefollowingexperiments,weinvestigatedhowejectingaheavy gas(withadensityabovethedensityofambientair)directlyaboveafog cloudaffectsthefogcloud.Hereto,asprayingdevicewasconnectedtoa30 fog-generatingdevice,suchthatthesprayingdevicewasactivatedtogether BE2025 / 5037 22 withthefog-generatingdeviceandejectedthegasdirectlyabovethefog cloudejectedbythefog-generatingdevice.Thefog-generatingdevice generatedaglycolfogcloudfromafog-generatingfluid,predominantly consistingofadipropylene / triethyleneglycolmixture,bymeansofaheat exchanger.5 Inafirstexperiment,thesprayingdeviceejectedXenon(Xe)gas (withadensityof5.8kg / m3)abovetheglycolfogcloudejectedbythefog- generatingdevice.Thiswasachievedbyplacingthegasoutletopeningof thesprayingdeviceabovethefogoutletopeningofthefog-generating device.Thisresultedinarapiddownwardflow,afasterhorizontal10 distributionandanincreaseddensityoftheglycolfogcloud. Inasecondexperiment,thesprayingdeviceejectedcarbonoxide (CO2)gas(withadensityof1.85kg / m3)abovetheglycolfogcloudejected bythefog-generatingdevice.Thislikewiseresultedinadownwardflow,a fasterhorizontaldistributionandanincreaseddensityoftheglycolfog15 cloud,albeitthedownwardflowwithCO2gaswasslowerthanwithXegas duetothelowerdensityofCO2gascomparedtoXegas. Thus,itcouldbeconcludedthatejectingaheavygas(agaswitha densityhigherthanthedensityofair1.2kg / m3)aboveaglycolfogcloud resultsinadownwardflow,afasterdistributionandanincreaseddensityof20 theglycolfogcloud.Forthepurposeoffoggenerationforsecurity applications,ejectingofaheavygasaboveaglycolfogcloudimprovesthe position,thehorizontaldistributionandthedensityoftheglycolfogcloud. Example2 ThisexampledescribesmoreindetailtheexperimentfromExample25 1,whereinthesprayingdeviceejectedCO2gasabovetheglycolfogcloud ejectedbythefog-generatingdevice.Asillustratedi.