Cov yas rwb thaiv tsev thiab sheath ntawm railway teeb liabkabyog tsim los ntawm kev nruam extrusion, thiab cov khoom siv extrusion yog ib qho ntsia hlau extruder. Nyob rau hauv cov txheej txheem extrusion, cov yas nyob rau hauv lub hopper nrog kev pab los ntawm lub ntiajteb txawj nqus los yog pub kauv rau hauv lub chim, thawb rau pem hauv ntej nyob rau hauv qhov kev txiav txim ntawm lub rotating ntsia hlau, tib lub sij hawm, cov yas yog stirred thiab extruded los ntawm cov ntsia hlau, thiab nyob rau hauv lub qhov. Kev txiav txim ntawm cov cua sov sab nraud ntawm lub thoob thiab cov shear kev sib txhuam kub ntawm cov yas thiab cov khoom siv, hloov mus rau hauv cov kua dej ntws hauv lub xeev, Nyob rau hauv cov kauv zawj rau hauv cov khoom siv tsis tu ncua, thaum tuaj txog ntawm lub tshuab taub hau, los ntawm cov pwm core thiab pwm ntawm lub annular gap extruded nyob rau hauv cov tub ntxhais nyob ib ncig ntawm txoj kab, tsim ntawm nruam rwb thaiv tsev los yog sheath txheej. Tag nrho cov txheej txheem extrusion tuaj yeem muab faib ua peb theem: sib tov, melting thiab homogenization; Extruded rau hauv ib lub cev; Txias thiab kho.
Nyob rau hauv cov txheej txheem ntawm yas extrusion, kev hloov ntawm cov khoom aggregation thiab viscosity ntawm cov khoom nyob ntawm qhov kub thiab txias. Qhov kub thiab txias muaj kev cuam tshuam zoo rau cov khoom tsim tawm thiab kev ua tau zoo ntawm cov khoom, tshwj xeeb tshaj yog cov xwm txheej plasticizing, uas tuaj yeem cuam tshuam ncaj qha rau lub cev thiab lub zog thiab cov khoom siv sab nraud. Txhawm rau yaj cov khoom siv rau hauv lub cev molten, qhov kawg kub ntawm lub extruder yuav tsum siab tshaj qhov viscosity kub ntawm cov khoom, thiab nws lub siab txwv kub yuav tsum tsawg tshaj li qhov decomposition kub ntawm cov khoom.
1. Yog tias extrusion ntawm qhov kub thiab txias muaj qhov zoo li hauv qab no: tsis tshua muaj kub extrusion khoom viscosity, yooj yim los tswj cov qauv qub, tsis yooj yim rau deformation; Qhov ntev ntawm lub tank txias tuaj yeem ua kom luv vim tias lub zog cua sov hauv extruder yog me me thiab lub sijhawm txias yog luv. Tsis tas li ntawd, qhov kub tsis tshua muaj peev xwm txo tau cov polymer degradation.
Disadvantages ntawm extrusion ntawm qhov kub thiab txias: tsis tshua muaj extrusion kub, tseem ceeb shear kev nyuaj siab, tseem ceeb shear tus nqi kuj tsis tshua muaj, yog li yooj yim rau tsim melt rupture, ua los ntawm ntxhib nto, tsis zoo brightness. Railway teeb liab cables feem ntau siv polyvinyl chloride. Yog hais tias qhov kub ntawm polyethylene tsawg dhau ntawm cov txheej txheem extrusion, nws cov crystallinity nce, ces cov kev ntxhov siab sab hauv tsim nyob rau ntawm ntug ntawm crystalline theem thiab amorphous theem yuav nce, uas yuav ua rau tawg ntawm rwb thaiv tsev los yog sheath nyob rau hauv lub sij hawm tom qab. Tsis tas li ntawd, qhov kub thiab txias yog qhov tsawg, cov khoom siv melting yog ncua ntev, los ntawm cov seem homogenized tawm ntawm cov yaj yuav tov nrog cov khoom siv, cov ntaub ntawv uas tsis tau yaj thiab yaj ua rau ntawm cov khoom, yuav ua rau cov khoom siv hluav taws xob thiab hluav taws xob ntawm rwb thaiv tsev los yog sheath poob, nyob rau tib lub sij hawm, tsis tag nrho cov khoom yas ntawm ib puag ncig kev nyuaj siab cracking kuj yog phem tshaj tag nrho cov plasticized.
2. Yog hais tias nyob rau hauv high kub extrusion muaj cov nram qab no zoo: zoo nto zoo; Zoo mechanical lub cev muaj zog; Cov khoom extruded viscosity txo qis, fluidity zoo, extruded zog noj yog me me. Txawm li cas los xij, qhov kub thiab txias heev yuav txo tau cov viscosity ntawm cov polymer, qhov ua kom tsis zoo ntawm fluidity yog ib qho yooj yim ua rau cov duab distortion thiab shrinkage ntawm cov khoom extruded. Tsis tas li ntawd, kub siab rau decomposition kub nyob ze rau lub polymer decomposition, thiaj li yuav txo tau lub cev khoom ntawm cov khoom los yog ua rau tsis zoo tsos. Yog li ntawd, viscosity kub thiab decomposition kub ntawm cov khoom yog ib qho tseem ceeb tsis rau lub molding txheej txheem ntawm cov ntaub ntawv polymer.
Txhawm rau ua kom tiav, yas extrusion siv qhov tsim nyog qis qis yuav tsim nyog dua.
Extrusion kub teem
Raws li cov txheej txheem kev hloov pauv ntawm cov khoom siv hauv lub thoob, cov ntsia hlau extruded tuaj yeem muab faib ua ntu pub mis, ntu melting, homogenizing seem 3. , teeb qhov kub ntawm txhua ntu raws.
1. Nyob rau hauv seem noj, thawj yog muab softening kub rau granular khoom yas, ua raws li los ntawm shear kev nyuaj siab generated ntawm kev sib hloov ntawm cov ntsia hlau thiab lub taag chim ua rau cov yas hais, mus cuag lub crushing ntawm softening khoom yas. Thiab qhov tseem ceeb tshaj plaws yog qhov kev sib hloov ntawm cov ntsia hlau los tsim kom loj txaus nruam thiab ruaj khov thrust thiab inverse kev sib txhuam, thiaj li yuav tsim ib tug nruam thiab ruaj khov extrusion siab, thiab tom qab ntawd paub qhov sib tov thiab sib xyaw ntawm cov yas, thiab kev siv thawj zaug ntawm kev sib hloov cua sov, thiaj li muab lub hauv paus rau kev nruam thiab ruaj khov extrusion. Nyob rau theem no, txawm hais tias qhov kev sib tw tsis tu ncua, zoo ib yam thiab ruaj khov, theem ntawm cov txheej txheem shear, thiab seb qhov sib tov zoo li cas yuav cuam tshuam ncaj qha rau qhov zoo ntawm extrusion thiab tso zis, yog li tsis tshua muaj kub yuav tsum tau siv nyob rau hauv seem pub. Cov seem no yog cov khoom noj, ua kom muaj zog txaus tuaj yeem thawb cov khoom mus rau pem hauv ntej, yog tias qhov kub thiab txias heev, cov yas yuav yaj ua ntej, tsis yog "cov khoom ntsaws", yooj yim ua rau cov yas decomposition, tab sis kuj ua rau extrusion siab fluctuation. thiab tsis sib xws plasticizing.
2. Nyob rau hauv lub melting seem, tom qab softening thiab pib sib tov ntawm cov yas sib tov, vim lub thrust kev txiav txim ntawm cov ntsia hlau, raws li cov ntsia hlau zawj mus rau lub taub hau ntawm lub tshuab, mus rau hauv lub melting seem. Nyob rau hauv lub melting seem ntawm qhov kub kom nce, qhov chaw ntawm qhov seem ntawm cov cua sov ntxiv rau cov cua sov sab nraud ntawm lub thoob, ntsia hlau rotation kev sib txhuam kub kuj plays ib tug tej lub luag hauj lwm. Lub thrust quab yuam los ntawm cov khoom noj thiab cov tshuaj tiv thaiv quab yuam los ntawm tus kheej-leveling seem, thiaj li hais tias cov yas nyob rau hauv pem hauv ntej tsim ntawm backflow, lub backflow generated nyob rau hauv lub ntsia hlau zawj thiab qhov sib txawv ntawm lub hau ntswj thiab lub thoob, tsis tsuas yog ua rau lub ntswj ntsia hlau. cov khoom sib xyaw ntxiv sib xyaw, tab sis kuj tseem ua rau cov khoom siv hluav taws xob hloov pauv, kom ua tiav qhov sib npaug ntawm qhov kub. Raws li qhov tshwm sim ntawm qhov kev txiav txim ntawm qhov kub ntawm theem no tshaj li qhov kub thiab txias ntawm cov yas, thiab ua haujlwm rau lub sijhawm ntev, cov yas hauv kev hloov pauv ntawm lub xeev thiab kev sib cuag nrog cov khoom siv hauv lub rhaub dej kub pib yaj, tsim ib txheej ntawm polymer yaj hauv cov khoom. chim deg membrane, xov thaum lub thickness ntawm yaj zaj duab xis nyob rau sab saum toj thiab chim clearance ntawm, yuav rotating ntsia hlau, Sau nyob rau hauv pem hauv ntej ntawm lub laub xov los tsim ib tug molten pas dej ua ke. Vim yog qhov txheeb ze txav ntawm lub thoob thiab cov hauv paus hniav ntawm cov xov, lub pas dej molten ua rau cov ntaub ntawv ntws tawm, thiaj li ua kom cov yas yas. 3. Nyob rau hauv seem homogenizing, qhov kub thiab txias txuas ntxiv mus, cov yas nyob rau hauv lub melting seem yog feem ntau plasticized, thiab ib feem me me ntawm cov polymer muaj pes tsawg leeg tseem tsis tau pib plasticizing, ib feem ntawm cov unplasticized hais no yuav tsum tau ntau dua plasticizing kub, vim hais tias. ntawm no, homogenizing seem ntawm qhov kub nce yog ua kom cov plasticizing thiab homogenizing kauj ruam.
4. Qhov kub ntawm lub caj dab ntawm lub tshuab ua kom qhov kub ntawm qhov sib npaug los yog nce me ntsis, vim hais tias lub rotating motion ntawm lub ntxeem tau phaj los ua cov linear motion ntawm cov yas, thiab muaj cov nyhuv thaiv ntawm lub lim, yog li ntawd lub cov khoom ntws tsis dhau du, thiab qhov kub thiab txias yuav tsum tsis txhob txo qis.
5. Lub taub hau kub yuav tsum yog me ntsis qis dua qhov kub ntawm lub tshuab caj dab, vim hais tias lub cev molten ntawm no muaj qhov chaw ruaj khov ntawm lub taub hau phab ntsa, qhov kub thiab txias yooj yim rau coke decomposition.
6. Kev tuag kub tuaj yeem txhim kho qhov ci ntsa iab, qhov zoo ntawm qhov chaw zoo, tab sis kev tuag kub siab dhau lawm, tsis tsuas yog yuav ua rau decomposition decomposition, ntau yuav ua rau molding txias teeb meem, yog li ntawd cov khoom yog nyuaj rau cov duab, yooj yim rau ntsug nws tus kheej. - deformation los yog flattening deformation; Yog hais tias qhov kub thiab txias yog txo, txawm tias cov khoom yog ib qho yooj yim rau cov duab, tab sis yooj yim los cuam tshuam qhov zoo ntawm nto.
