Polyurethane insulation pipe market demand is increasing
Release time:
2018-12-07
Author:
Source:
China'spipelinemarketdemandisgrowingandgrowingrapidly.Theemergenceofthissituationismainlycausedbythefollowingreasons:1.Chinapromotestheneedsofenergyconservationandenvironmentalprotectionpoliciessuchas“centralheating”,“cogeneration”and“triplesupply”;2.AcceleratingandmodernizingcivilizedurbanconstructionHighrequirementsforenergyconservationandenvironmentalprotection;3.Inordertoimprovethequalityoflifeofthepeople,thecountry'sheatingrangeextendsfromthesevere“threenorth”areas(ieNorthChina,NortheastChina,NorthwestChina)tothe“transitionarea”ofthevastwinter,coldandhotsummer.demand.Wehavemadegreatprogressinresearch,development,application,etc.:Inordertomeettherapiddevelopmentofthedirectburiedsteampipeline,China'svastnumberofscientificandtechnicalpersonnel,manufacturersinthedirectburiedsteampipelinetechnologyresearch,development,application,etc.,paidAlotofhardworkhasmadegreatprogress.Thevarietyofinsulationstructureandselectionofmaterials,thescaleofengineeringpractice,nocountryintheworldcancomparewithus. Germany,Brugge,Soksam,ItalyandtheUnitedStatesandothercompanies,theirgeneraldiameterΦ500mm,theamountisnotlarge,andcurrentlyChina'sShandongJinan,HebeiShijiazhuang,ShaanxiXi'an,LiaoningDalian,Henan,JiangsuandZhejiangandotherregionsThedirectburiedsteampipelinehasexceededΦ500mm,andsomehavereachedΦ900mm.Thethermalinsulationstructurehasinternalslidingandexternalsliding.Theselectedhigh-resistancematerialsincludemicroporouscalciumsilicate,glasswoolshell,hotpressedperlite,siliconbeadinsulationmaterial,andcompositesilicate.Insulationstructuretype,therearemanytypesofinsulationmaterials.Therefore,inthefieldofdirectburiedsteampipelinedevelopmentandapplication,Chinaisnolessdevelopedthanthedevelopeddirectburiedthermalinsulationpipefromthetransportmediumsteelpipe,polyurethanerigidfoamplasticinsulationlayerandglassfiberreinforcedplasticoutersheath(glassfiberreinforcedplastic)tightlycombined.Ithasgoodmechanicalstrengthandexcellentcorrosionresistance.Thefirstlayer:workingsteelpipelayer,accordingtothedesignandcustomerrequirements,generallyuseseamlesspipe(GB8163)spiralweldedpipe(GB9711;SY/T5038)andstraightseamweldedpipe(GB3092).Afterthesurfaceofthesteelpipeistreatedbyadvancedshotblastinganddescalingprocess,therustremovalgradeofthesteelpipecanreachSa2gradeinGB8923-standard,andthesurfaceroughnesscanreachR=12.5microninGB6060.5standard.Afterthesurfaceofthesteelpipeisdecontaminatedandrusted,alayerofanticorrosivematerialisapplied.Thefirstfunctioniswaterproofing,andtheotheristoimprovethebondingsurfacebetweentheheatinsulatinglayerandthesteelpipetoformawhole. Thesecondlayer:apolyurethaneinsulationlayer,whichisformedbyinjectingarigidpolyurethanefoamrawliquidintoacavityformedbetweenthesteelpipeandthespecialsteelmoldbyahigh-pressurefoamingmachine.Thatiscommonlyknownasthe"moldfoamingprocess."Whetherthepolyurethanefoamisfullornot,thereareanyqualityproblemsfordirectinspection.Itsroleistowaterproof,buttokeepwarm,andthethirdistosupporttheweightoftheheatingnetwork.Whenthetemperatureoftheconveyingmediumis:-50°C-120°C,therigidpolyurethanefoamisusedastheinsulatinglayer;whenthetemperatureoftheconveyingmediumis-50°C-150°C,therigidpolyurethaneisused.Thefoamismadeofinsulation. Polyurethanedirect-buriedinsulationpipe,alsoknownas"tube-in-pipe",consistsofa"two-stepprocess"consistingofahigh-densitypolyethyleneouterprotectivelayer,apolyurethanerigidfoamplasticpipeandasteelpipe.Theinsulationlayermaterialisarigidpolyurethanefoamwithadensityof60kg/m3to80kg/m3,whichfullyfillsthegapbetweenthesteelpipeandthecasing,andhasacertainbondingstrength,sothatthesteelpipe,theoutercasingandtheheatinsulationlayerarebetweenthethree.Formasolidwhole.Polyurethanedirect-buriedinsulationtubefoamhasgoodmechanicalpropertiesandthermalinsulationproperties.Generally,itcanwithstandtemperatureof120°Cbymodificationorcombinationwithotherinsulationmaterialstowithstandtemperatureof180°C.Outlinedtoadapttourbandistrictheatingandwork. Polyurethaneinsulationdirectburiedpipeshavebecomearelativelymatureadvancedtechnologyinsomedevelopedcountries.Inthepasttenyears,China'sheatingengineeringtechnicianshavepromotedthedevelopmentofdomesticpipenetworktechnologytoahigherlevelbydigestingandabsorbingthisadvancedtechnology.Thepracticeresultsinmorethantenyearshavefullyprovedthatthelayingmethodofpolyaminecheeseinsulationdirectburiedpipehasmanyadvantagescomparedwiththetraditionaltrenchandoverheadlaying.Thedirectburiedheatpreservationpipeismadeupofasteelpipeconveyingmedium,ahigh-densitypolyethyleneoutercasing,andarigidpolyurethanefoaminsulationlayerbetweenthesteelpipeandtheoutercasing.ThisisalsothepolyaminecheeseinsulationdirectlyburiedpipeinChina'sheatingproject.
Key words:
Latest developments