Rural Water Supply in Nepal Pipes and Fittings尼泊爾農(nóng)村供水管道和配件 31

1/1RuralWaterSupplyinNepalPipesandFittings尼泊爾農(nóng)村供水管道和配件3APPENDIX1:OPERATINGABL012TORCI!Theblowlampisaportablekerosenetorchusedtoproduceintenselocalheat,metals,formeltingheatingmetalsandsoldering.Thebloly-torchcanalsobeusedinweldingHDPpipeandfittings,Operatingablowtorch1.Fillthetankto3/4withkerosene.Useafunnelwithafiltersothatdirtwillnotflowintothetankandblocktheoutlet.2.Opentheairvalve.3;Filltheoilcupwithkerosene.4.Lightthekeroseneintheoilcup,matchinthecup.Leavetheburning5.Letthekerosenealmostburnout.6,Closetheairvalve.7.Pumptheairpump15to20times.8.Afterpumpingthetorchshouldstartburning.Ifitgoesout,repeattheaboveoperation.9.Pumpmoreifamoreintenseflameisrequired.10.Todecreaseflameintensityopentheairvalveslightlytolowertheairpressure,11.Iftheflamesmokesorfluctuates,cleantheoutletwithacleaningneedle.12.Toputouttheflameopentheairvalvealltheway.I-18-APPENUZX2:MaLLedandMituBoxMUULVFORSTRAZGUTPZPEWELUZNG!ULt6ohwczih!ingltimMZTRE-19-3,GIpipe.andfittings3.1Introduction3.1-lGeneralGalvanisedironpipesareusedasservicepipesincrossingrivers,reducers.intankinstallationsandpressureThisispossiblebecauseoftherigidityandhighpressureratingofGIpipe.GIpipeand.mostofthefittingsareusuallylocallyavailableinthebazaar,TheabbreviationGIisshortforGalvanisedIront.Density:Colour7.85gm/cc.:Grey-galvanized.83.1.2AdvantagesofGIpipeandfittings-Mechanicalstrengthandhighpressurerating.-Locallyavailable.-Cementwilladheretothemetalafterthegalvanisationhasbeenremoved.Thismakesitpossibletousethepipeinconcretestructuressuchasreservoirs.3.1.3DisadvantagesofGIpipeandfittings--Nopossibilityofmakingfittingslocally.-Highlossofwaterpressureduetointernalfriction.-LowresistancetochemicalcorrosionascomparedwithHDPorotherplasticpipe.-HighercostthanHDPorotherplasticpipe.-Heavyweight.3.2StandardsupplyofGIpipeandfittings.3.2.1GeneralThefollowingsectionsgiveabriefdes-criptionofeachGIitemnormallyusedinconstructingwatersupplysystemsofthegravity-flowtype.(Refertosection2.2.1forpipesizedescription).3.2.2PipeGIisanabbreviationofGalvanisedIron,atermbroadlyusedtodescribemetalpipeofthetypecommonlyutilisedintheinstallationofgas,waterandsteamconduits.Althoughsuchpipeisnormallymadeofmildsteel,itisneverthelesswidelyreferredtoasGI.-10-Itispossibletoprocuresuchpipewithoutthegalvanisationbutitisusuallygal-vanised(coatedwithanthinlayerofzinc)topreventotherwiserapidrustingofthepipe.Forthisreason,GIpipeshouldnotbebent.Ifthisisdonethegalvanisationwillcrackandthepipewillbegintorustatthatpoint.Ifabendisrequired,anappropriatefittings(e.g.anelbow)shouldbeused.GIpipeisnormallydeliveredinsinglelengthsof6metreseach.Eachlengthshouldhaveasocketscrewedtooneend.Thepipeismanufacturedinthreecatego,iesaccordingtoits*weightandpressure-bearingcapacity.ClassA);Thecategoriesare:l-light(formerly2-medium(formerlyClassB);3-heavy(formerlyClassC).ThecategorymostreadilyavailableinhardwarestoresinNepalisofthelightgrade.Pfediumandheavygradescanalsobepurchasedbutforthosegradesanadvanceorderisgenerallyrequired.Thethreetablesgivenbelowdescribedthebasiccharacteristicsofeachgradeofpipe.a)LiahtkrradeINSIDZDIAiuiETER(INCHES)211323OUTSIDEWALLRECOMFENDED31AMETERTHICKNESSWE1GHT(mm)WORKINGPRESSUREmuoG(kg/sq.cm.)21.22.00.9510.633m52.72.0110.648.12.93.25a.859292.94.117.088.33*36.817.0b)MediumgradeOUTSIDErlALLRECOMENDEDDIAlETERTHICKNESSWEIGKTNCHES),:(ml(kdm)WORKINGPRESSURE.bdh.hcm)3I21.42.7112221.1I2.44I21.1I1B48.43033.6117.6260.23@75.10i4.188.84.1a.4714.1--I-21-1NSII;IEDIATSR(INCHES)311*23.GUTSIDE+/ALLRECOQGXJDZDDIABIETZRTHICKNES.3tiZICYTWORKINGPRESSURE(mm)(mm)(M/m)(kdw~cm)21.43*31.4524.633.84.1219724.648.44.14.4322.160.24.56.1717.688.8b*910.1017.6Importantnote:Incalculatingtherecommendedworkingpressure,;;;a@ifasaretyractorof4isincludedinordertoallowforoccasionallyit.#i,1.;highwaterpressurewhichresults,fromsurgepressure,waterhammeri::etc.withinthepipe,UnderworkingconditionswhicharegenerallyI.:,freeofexceptionallyhighpressureswhichresultfromsurging,or::othersuchcauses,thepipecanbeusedunderpressureconditionsupi,:to4timestherecommendedworking.pressure.Thisappliestoallis.threegrades.Forexample,thiscouldmeanthat1lightgradepipe.::couldbesafelyusedunderpressuresofupto42.4kg/sq.cm.;2::heavygradepipecouldbeusedunderpressuresofupto70.4kg/sq.cm.-,providedthatintermittentlyveryhighpressuresasdescribedabovearenotexpected.3.2.3FittingsMostGIfittingsarenormallymadeofeithermediumorheavygrademildsteel.Certaintypes,suchassockets,aresometimesmadeoflightgrademildsteel,andthisshouldbekeptinmindwhiledesigningasystemassuchfittingsarenotasdurableasthoseofmediumorheavygrademildsteeltobringOnewayofgettingaroundthiswouldbesparefittingstothevillage.Forexample,if10elbowsarerequiredforacertainsystem,15couldbebroughttotheworksite.Thiswouldallowforsparesandforreplacementsincasesomeofthepartswerefoundtobedefective.Onthefollowingpages,themostcommonlyusedGIfittingsaredescribed.-22-ABOWEIJOWhJSI)UCINGYOCKETSItEDUCINGBUSHISCAPS-23-UNIONNIBPLB-24-3.3HandlingofGIpipe3.3.1TransportGIpipesareheavy.carefullv.TheyshouldbetreatedIfthegalvanisationisdamaged,starttorust.thepipewill3.3.2StorageGIpipeshavecorrosion,soabovegroundothermeans.3.4JoiningofGIpipe3.4.1ToolslowresistancetochemicalitisbettertostorethemlevelbyusingsupportsorToworkwithGIpipes,thefollowingtoolsarerequired:.-Pipewrench-Plumberstablewithvice-Shiftingspanner-Hammer-File-Chisel-Hacksaw(withbaldes)-Tapeandpencil-Dieset-Spiritlevel3.4.2ThreadcuttingMeasureandmarkthelengthofpipetobethreadedandcutthepipewiththehacksaw.Incuttingthepipe,evenstrokesshouldbeusedashasty,irregularstrokesrapidlywearouttheteeth,Thesawblademustbekeptstraight,Afterthepipehasbeencut,adiesetisusedtothreadtheendofthepipe,{lproperlycutpipe-endmakesthepipeeasiertothread.a)Usethesetofteethwhichcorrespondstothediameterofthepipetobethreaded.b)Putoilontheendofthepipewhichistobethreaded.clFixthemachineinsuchawayastoplacetheguidingteethonthepipe.d)Beginthdthreadcutting.Therehastobeasufficientquantityofoilonthesurfacetobethreadedduringtheentirecuttingoperation.e)Thelengthofthreadtobecutvarieswiththediameterofthepipeaccordingtothetablegivenbelow.Thethreadshavetobecutinthreeworkingoperations.f)Cleanthethreadandtestitbyfittingasocketonthethreadedpipeend.-25-13171%.19224330-Manyofthelocallyavailablediesetsareoflowquality,andaddedcareshouldbetakeninusingsuchsets.Thesesetshavenoguidingteeth,nofixedpointforthecuttingteethandtheyaredifficulttouseinthreadinglargediameterpipe.3.4.3Water-tightjointsAlthoughseveraltypesofmaterialscanbeplacedonthreadstomakethejointwater-tight,onlydryhempandnon-poisonousjointpaste(puttyoranimalgrease)shouldbeused.Becausepaintbecomesveryhardwhenitdries,itisnotrecommendedasjointpaste.a)Toguaranteewater-tightnessthethreadshavetoberoughenedwithanoldhack-sawbladesothatthehempwillremaininthethread.b)Turnthehempinaclockwisedirection,startingatthebeginningofthethread(endofthepipe),coveringtheentirethreadwithhemp.._clPutjointpasteonthethreadhemp.Ensurethatnohemp,oilorjointpasteremainsinsidethepipe.d)Fixthefittingonthepipeby-handandItightenwithapipewrenchuntilreasona-.*.blytight.Ifturnedtootight,thefittingmaystretchorcrack.eCutoffthevisiblehempwithanoldhacksawbladebymovingitcounter-clockwise.Theconicalformofthreadscontributestowater-tightness,Ifalotofhempcomesoutofscrewedfittings,itmeansthatthehempwasnotfixedcorrectly.Toolsmustalwaysbekeptclean,especiallytheteethofpipewrenches.-26-4.Miscellaneousvalves4.14.2GatevalveGatevalvesarenormallyusedinsituationswhereafullpipeflowisrequiredbutwhereitisoccasionallynecessarytoshutofftheflowcompletely.Gatevalvesshouldnotbeusedincontrollingflow.Inotherwords,gatevalvesshouldnotbeleftpartiallyopen-theyshouldeitherbecompletelyopenorcompletelyclosed.Thegateofthevalveiswedgeshapedandthisgatecutsofftheflowwhenthevalveisclosedandthegateisloweredintoagroovecastinthebodyofthevalve.Thevalveopeningisusuallyofthesamediameterastheinsideofthepipetowhichitisfittedandthevalve,whencompletelyopen,offersverylittleresis-tancetowaterlow.Gatevalveswhichareleftshutforalongtimetendtostickshut,afterwhichgreatforceisrequiredtogetthegateoffthesealing.Similarly,valveswhichhavebeenleftopenforalongtimemaynotcloseproperlybecauseofdirtcollectedinthegategroovewhichpreventsproperloweringofthegate.Ifagatevalvehasnotbeenopenedorclosedforyearsafterthattimeitmaynotbepossibletooperateitatall.Theseproblemscanbeavoidedbyregularlyopeningandclosingthe-nlves.Globevalveorstopcock(corporationcock)Thesevalvesderivetheirnamef