Diving Suit Definition 潜水服的定义

Adivingsuitisanitemofclothingordevicedesignedforprotectingdiversfromtheunderwaterenvironment.Moderndivingsuitscanbedividedintotwokinds:ambientpressureor"soft"divingsuitsandatmosphericpressureor"hard"divingsuits.Standarddivingdressisnowobsoletebutishistoricallyinteresting.

Ambientpressuredivingsuits

Ambientpressuredivingsuitsareaformofexposureprotectionusedinscubadivingorfreediving.Theyprotectdiversfromthecoldandprovidesomedefencefromstinginganimalsandfromabrasiveandsharpobjectsandanimalsunderwater,buttheydonotprotectdividersfromthepressureofthesurroundingwater.

Unlikeatmosphericdivingsuits,ambientpressuredivingsuitsprovidenoprotectiontothediverfrombarotraumaordecompressionsickness.

Thesuitsareoftenmadefromneoprene,heavy-dutyfabriccoatedwithrubber,orPVC.

Asideeffectofdivingsuitsisthattheyalsoprovidebuoyancy,whichthedivermustcontrolunderwater.

Therearemainfourtypesofambientpressuredivingsuits:

Wetsuits

Wetsuitsareusedtypicallywhendivinginwatertemperaturesbetween10and25oC(50to80oF).

Amodernwetsuitismostlymadefromthinneoprene,whichprovideslimitedthermalprotection,andlinedwithanylonfabrictomakeiteasytoputonandtakeoff.

Awetsuitallowsasmallamountofwaterintothesuit,buttrapsthisthinlayerofwaterbetweentheskinandtheneoprene,whichbodyheatthenwarmsup.Theneopreneitselfinsulatesthewarmlayeragainstthecoldofthesurroundingwater.Aclosefitisessentialtoensurethesuitefficientlyworks,astoolooseafitwillsimplyallowthewarmlayertoflushawayandbereplacedbycoldwater.

Thereissomecontroversyoverwhoinventedthewetsuit.MostsayitwasJackO’Neillwhostartedusingneoprene,whichhefoundliningthefloorofanairliner,tomakeasimplevest.Hewentontofoundthesuccessfulwetsuitmanufacturer,O’Neill.Ontheotherhand,BobandBillMeistrell,acoupleofkidsfromManhattanBeach,California,claimtohavestartedexperimentingwithneoprenearound1953.TheircompanywouldlaterbenamedBodyGlove.

Wetsuitscomeindifferentthicknessesdependingontheconditionsforwhichitisintended.Thethickerthesuit,thewarmeritwillkeepthewearer.Athicksuitisstiff,somobilityisrestricted.Awetsuitisnormallydescribedintermsofitsthickness.Forinstance,awetsuitwithatorsothicknessof5mmandalimbthicknessof3mmwillbedescribedasa"5/3"Differenttypesofwetsuitareavailable,froma"shorty"(shortarms,shortlegs)toa"longjohn"(fulllengtharmandlegs).

Wetsuitsarecheapandsimple.Theylosebuoyancyandthermalprotectionastheycompressatdepth.

Wetsuitsarealsocommonlywornforwatersportactivitiesotherthandiving,suchaswindsurfing.

Drysuits

Drysuitsareusedtypicallywhendivinginwatertemperaturesbetween0and15oC(32to60oF).

Sealsatthewristsandneckpreventwaterenteringthesuit.Evenso,thediverwillbedampafteradiveinadrysuitduetosweatandcondensation.Thesealsareeithermadefromlatexrubberorneoprene.Latexsealssurviveforamaximumoftwoyearsbutaresupple.Neoprenesealslastlongerbutallowmorewatertoenterbecause,beingstiffer,theydonotmakeeffectivesealsinthecontoursofthewristandneck.

Thesuithasanairinflationvalve,whichallowsthedivertocontrolthebuoyancyofthesuitbyinjectinggasfromthedivingregulatortoavoidsqueezeduringdescent.Italsohasanairventvalve,whichallowsthedivertoventoffhigherpressuregasfromthesuitduringtheascent.Ventvalvescanbeautomatic,operatingaspressurereliefvalves,ormanual,wherethedivermustraisethevalvetovent.Automaticventsaregenerallylocatedattheshoulderandmanualventsarelocatedatthewrist.Thetypicaldrysuithasbuilt-inboots.Ithasazipper,forentryandexit,acrossthebackoftheshouldersordiagonallyacrossthefrontofthetorso.

Therearetwotypesofdrysuit:

• Membranedrysuitsareconstructedfrommaterialswithlowthermalinsulationsuchasvulcanisedrubberoratrilaminateofnylon,butylrubberandnylon.Sothedivermustwearaninsulatingundersuit.Membranedrysuitsarecomfortabletoputon,getoffandwear.Theycanbeunreliablebecausethesuit抯buoyancyandinsulationdependsontheairtrappedintheundersuit:ifthesuitsispuncturedthebuoyancyandinsulationislost.
• Neoprenedrysuitsareconstructedfromneoprene,abuoyantandthermallyinsulatingmaterial.Thisbuilt-inbuoyancyandthermalprotectionmakesthemsafertowearthanmembranedrysuitswhenpuncturedbecausetheymaintainsomeofthosepropertieswhenflooded.Beingmadeofafairlyrigidandheavymaterial,theyare,however,difficulttogetonandoffandtheirbuoyancyandthermalprotectiondecreaseswithdepthastheneopreneiscompressed.Neoprenealsotendstoshrinkoveraperiodofyears.Analternativeiscrushedneoprene,whichislesssusceptibletovolumechangeswhenunderpressureandshrinksless.

Semi-drysuits

Semi-drysuitsareusedtypicallywhendivinginwatertemperaturesbetween10and20oC(50to70oF).

Sealsatthewristsandnecklimitthevolumeofwaterenteringandleavingthesuit.Thedivergetswetinasemi-drysuitbutthewaterthatentersissoonwarmedupanddoesnotleavethesuitreadily,sothediverremainswarm.Thetrappedlayerofwaterdoesnotaddtothesuit’sinsulatingability.Anyresidualwatercirculationpastthesealsstillcausesheatloss.Butsemi-drysuitsarecheapandsimplecomparedtodrysuits.Theyareconstructedfromthickneoprene,whichprovidesgoodthermalprotection.Theylosebuoyancyandthermalprotectionasthetrappedgasbubblesintheneoprenecompressatdepth.Semi-drysuitscancomeinvariousconfigurationsincludingasinglepieceortwopieces,composedof’longjohns’andaseparate’jacket’.Semidrysuitsdonotusuallyincludebootssoaseparatepairofinsulatingbootsareworn

DiveSkinsandJeans

Skinsareusedtypicallywhendivinginwatertemperaturesabove25oC,77oF.TheyaremadefromLycraandprovidelittlethermalprotectionbutsimplyprotecttheskinfromstingsandabrasion.Lycrabecamepopularapproximately20yearsago,andisstyledafterwomen’snylonstockings.Aussielifeguardsworenylonstoprotectagainstjellyfishstingswhenonrescues.Thedownsideoflycraisthatitcanshredwhencontactinganabrasivesurface,andthatitcanbecostly.

Theoriginaldiveskinswereaneoprenejacketandtightjeansandknownasa’TopandLevis’.Jeanshaveanegativebuoyancyofapproximately8oz.Somediversbelievethemtobeexcellentdivingskins.Theyofferminimalthermalprotectionbutgoodprotectionagainstsun,abrasion,andstings.Theycanbepurchasedslimfitortaperedandwillshrinktofit.Jeanscanalsobetuckedintodivebootsorcuffedtopreventdragunderwater.Withstreetclothesandat-shirtordivetoponehasthebasicsforasafeandfundive.However,jeansprovideverypoorthermalcharacteristicsoutofthewater.Wetjeansstayverywetandverycoldinevenmoderateclimates.Somoderndiveskinsmaybepreferableinallbutthewarmestconditions.

Atmosphericdivingsuits

AnAtmosphericDivingSuitorADSisaperson-shaped,articulatedsubmersiblethatprovidesthe"diver"withaenvironmentatoneatmosphereofpressureatanydepth.Theycanbeusedforverydeepdives,600metres/2000feet,formanyhourswithoutthenormalhazardsofdepth,suchasthedecompressionsicknessornitrogennarcosis.

Theylooklikesuitsofarmour,withelaboratepressurejointstoallowarticulationwhileresistingthelargedifferencebetweentheinsideandoutsidepressure.Theyareoftenconstructedfromaluminium,weigharound250kg/500poundsandhavepropellersallowingthemtomoveinwater.Oftentheyareloweredfromasupportvessel,whichsuppliesbreathinggas,electricpowerandcommunicationstothesuitthroughanumbilicalcable.Thesuitmayincorporatearebreather-typebreathingsystemintheeventofanemergencywheretheumbilicalsupplyfails.