Fusion Vuam yog dab tsi
Fusion welding koom nrog cov yeeb nkab yas los ntawm melting mating nto thiab nias lawv ua ke kom lawv sib sau ua ke rau hauv ib qho khoom siv tas mus li ntawm qhov txias. Vim tias nws tsim ib qho kev sib koom ua ke uas tsis muaj cov khoom siv ntxiv thiab tsis muaj cov khoom siv kho tshuab, nws yog txoj kev nyiam rau polyethylene thiab polypropylene siab yeeb nkab. Ob variants dominate:
Butt fusion.Ob lub yeeb nkab kawg ntawm tib txoj kab uas hla thiab phab ntsa tuab yog ntsib square, rhuab tawm tsam ib lub phaj kub kom txog thaum cov khoom ncav cuag lub xeev uas tau hais tseg, tom qab ntawd nias ua ke hauv kev tswj xyuas.
Electrofusion.Lub molded haum uas muaj ib tug embedded cua sov kauj yog ntog nyob rau hauv lub npaj cov yeeb nkab xaus thiab ib tug hluav taws xob tam sim no nce lub interface rau melting point, nrog rau cov kev sib koom tsis tswj electronically.
Ob txoj kev yog nyob ntawm qhov dav dav, zoo txhais qhov rais nruab nrab ntawm qhov kub thiab txias ntawm cov polymer softens thiab qhov kub ntawm qhov nws pib degrade. Polyethylene muaj xws li lub qhov rais, thiab cov txheej txheem fusion rau nws yog standardised, nrog rau cov kev txwv los ntawm cov yeeb nkab txoj kab uas hla, phab ntsa thickness thiab cov khoom qib.
Vim li cas PVC thiaj txawv
PVC, los yog polyvinyl chloride, yog ib tug thermoplastic thiab yog li ntawd nyob rau hauv lub hauv paus ntsiab lus yuav softened thiab hloov dua siab tshiab. Nyob rau hauv kev xyaum, unplasticised PVC muaj lub qhov rais nqaim heev. Nws pib tso tawm hydrogen chloride thiab degrade ntawm qhov kub thiab txias tsuas yog me ntsis saum toj ntawm qhov ntau uas nws dhau los ua kua dej txaus, yog li lub pas dej molten, weldable ntawm cov khoom tsis tuaj yeem tuav tau rau lub sijhawm uas lub pob tw fusion lossis electrofusion voj voog xav tau. Txhim kho qhov kub thiab txias kom txo viscosity accelerates decomposition ntau dua li kev txhim kho ntws, thiab cov khoom degraded ntawm qhov sib koom ua ke yog nkig thiab tshuaj tiv thaiv tsawg dua li cov yeeb nkab lub cev.
Qhov thib ob qhov txawv yog rheology. Unplasticised PVC yog ib qho amorphous polymer nrog cov yaj viscosity siab piv nrog cov semi-crystalline polyolefins, yog li cov interdiffusion ntawm polymer chains uas tsim kom muaj suab fusion daim ntawv cog lus qeeb thiab nyuaj rau ua tiav thoob plaws hauv cov yeeb nkab phab ntsa. Ib feem peb yog tias PVC muaj qhov sib piv qis ntawm thermal expansion piv nrog polyethylene, yog li ob hom yeeb nkab nthuav dav thiab cog lus sib txawv; qhov no ib leeg yog txaus los ua kom sib xyaw- cov ntaub ntawv welded system dimensionally inconsistent.
Lub tswv yim xaus yog tias pob tw fusion thiab electrofusion, raws li tus qauv rau polyolefin yeeb nkab, tsis siv rau PVC siab yeeb nkab. Fusion vuam yog cov txheej txheem raug rau polyethylene rau cov qauv xws li ASTM F2620 thiab ISO 21307, thiab rau polypropylene thiab polyvinylidene fluoride systems ntawm lawv tus kheej cov lus, tsis yog rau PVC.
Txais Kev Koom Tes rau PVC Yeeb Nkab
| Txoj kev | Nws ua haujlwm li cas | Hom kev siv |
| Solvent cement sib txuas | Solvent cement softens ob qhov chaw thiab qhov chaw fuse raws li cov kuab tshuaj evaporates | faus thiab saum toj no - hauv av siab thiab cov kav dej, ua raws li ASTM D2855 |
| Gasketed thawb- haum rau kev sib koom ua ke | Lub nplhaib roj hmab nyob rau hauv lub qhov (socket) seals tiv thaiv tus spigot thiab tso cai rau txav mus | Cov dej faus thiab cov kav dej phwj tuaj, raws li ASTM D3139 |
| Flanged kev sib txuas | Flanges nrog lub gasket yog bolted ua ke | Kev sib txuas rau cov li qub, twj tso kua mis thiab cov khoom siv uas yuav tsum tau dismantling |
| Mechanical thiab compression fittings | Couplings, eeb thiab compression rings tuav cov yeeb nkab | Kho, khi-ins thiab hloov mus rau lwm yam ntaub ntawv |
| Threaded sib koom ua ke | Taper threads nrog sealant los yog daim kab xev | Cov kab me me thiab cov khoom siv sib txuas uas yuav tsum muaj kev sib txuas tsis tu ncua |
Txhua txoj kev nws muaj nws txoj cai npaj. Kev sib koom ua ke ntawm cov cement sib txuas yuav tsum tau ntxuav, square txiav, lub teeb chamfer, cov cement kom raug rau cov yeeb nkab txoj kab uas hla thiab lub sij hawm kho tau ua ntej kev ntsuas siab uas nyob ntawm qhov kub thiab qhov sib koom ua ke. Gasketed pob qij txha yuav tsum tau lub nplhaib yuav tsum tau zaum kom raug thiab lub spigot insertion qhov tob yuav tsum tau cim, nrog rau kev tso cai rau thermal zog. Flanged thiab threaded pob qij txha yuav tsum tau tswj bolt torque thiab ib tug sib haum sealant.
Qhov twg welded yas yeeb nkab yog cov lus teb zoo
Thaum welded tag nrho, xau- yuav tsum muaj cov yas pub dawb, cov khoom siv yuav tsum tau txav mus rau lub welded polymer es tsis yog PVC. Polyethylene yog siv rau faus dej thiab roj faib, polypropylene random copolymer rau cov dej kub thiab cov kav dej, thiab polyvinylidene fluoride qhov twg tshuaj tiv thaiv ntawm kub siab dua yog xav tau. Rau kev kub siab thiab kub kub kab, carbon steel yeeb nkab nrog cov pa arc vuam, los yog cov khoom siv hlau, tseem yog cov lus teb ntawm engineering, thiab cov tshuab no tau tswj hwm los ntawm lawv tus kheej cov kav dej siab.
Qhov twg PVC tau teeb tsa thiab muaj qhov xau tau tshwm sim ntawm qhov sib koom ua ke, kev kho kom raug yog txiav tawm qhov sib koom ua ke, nruab ib ntu tshiab nrog cov cement hnyav lossis cov khoom siv sib txuas, thiab rov ua dua - kuaj, tsis txhob siv cua sov rau thaj tsam puas. Thaum tshav kub kub ntawm PVC yeeb nkab ua rau lub zos degradation thiab ua rau cov kev sib koom ua ke yuav ua tsis tau dua.
FAQ
Q: PVC yeeb nkab puas tuaj yeem fusion welded?
Tsis yog los ntawm lub pob tw fusion lossis electrofusion txheej txheem txheem rau polyolefin yeeb nkab. PVC degrades ntawm qhov kub thiab txias tsuas yog me ntsis saum toj ntawm qhov uas nws dhau los ua kua, yog li lub pas dej molten ruaj khov tsis tuaj yeem tuav ntev txaus los tsim cov suab paj nruag.
Q: Dab tsi yog txoj hauv kev zoo tshaj los koom nrog PVC yeeb nkab?
Cov kuab tshuaj cement sib koom ua ke rau ASTM D2855 yog txoj hauv kev zoo tshaj plaws rau cov kab siab thiab cov kav dej, nrog gasketed thawb - haum cov pob qij txha rau ASTM D3139 siv rau faus mains thiab flanged pob qij txha siv ntawm cov khoom sib txuas.
Q: Vim li cas fusion vuam haum rau polyethylene tab sis tsis PVC?
Polyethylene muaj qhov ua haujlwm dav dav ntawm softening thiab degradation thiab qis dua yaj viscosity, yog li nws cov saw interdiffusion tsim ib qho kev sib koom ua ke. PVC muaj lub qhov rais nqaim, siab dua yaj viscosity thiab tso tawm hydrogen chloride ntawm overheating.
Q: Puas tuaj yeem siv electrofusion fittings ntawm PVC yeeb nkab?
Tsis yog. Electrofusion fittings yog tsim thiab dimensioned rau weldable polyolefin yeeb nkab xws li polyethylene. Kev siv lawv rau PVC tsis tsim cov fused sib koom ua ke thiab tsis yog qhov kev lees txais kev coj ua.
Q: Ntev npaum li cas yuav tsum muaj qhov hnyav cement sib koom ua ntej kev sim siab?
Lub sijhawm kho yog nyob ntawm cov yeeb nkab txoj kab uas hla, cov cement siv thiab qhov kub thiab txias, thiab cov txiaj ntsig tau muab rau hauv cov qauv sib koom ua ke thiab cov ntaub ntawv tsim cov cement. Kev kuaj thaum ntxov yog ib qho ntawm feem ntau ua rau kev sib koom ua ke tsis ua haujlwm.
Q: Dab tsi yuav tsum tau siv thaum yuav tsum tau ua tiav cov kab yas welded?
Xaiv lub weldable polymer xws li polyethylene, polypropylene random copolymer los yog polyvinylidene fluoride thiab ua raws li tus qauv fusion rau cov khoom ntawd. Rau kev kub siab thiab kub kev pab cuam, welded carbon steel yeeb nkab tseem yog cov qauv kev daws teeb meem.
