Yellowing Tubes
Thaum lub sijhawm tshuaj xyuas niaj hnub no, cov neeg ua haujlwm saib xyuas pom tias cov khoom siv hluav taws xob dawb PTFE cov raj kub kub tau teeb tsa ob xyoos dhau los tau tig daj-xim av. Lub discoloration yog uniform ntawm ib co hlab, patchy rau lwm tus. Lub tshav kub exchanger tseem ua raws li specification. Chav siab thiab cov zis hluav taws xob tsis hloov pauv. Lo lus nug: Puas yog cov tshuaj pleev ib ce no, lossis nws puas yog qhov teeb meem ntawm cov khoom siv degradation uas cuam tshuam rau txoj kev ncaj ncees ntawm lub raj?
PTFE discoloration muaj ntau yam ua rau, xws li los ntawm tsis muaj teeb meem nto staining mus rau hnyav thermal lossis tshuaj degradation. Qhov sib txawv ntawm lawv yuav tsum tau txheeb xyuas tus qauv, txheej txheem chemistry, thiab keeb kwm kev ua haujlwm kub. Kev kuaj mob tsis raug- hloov cov raj uas tsuas yog stains, lossis txuas ntxiv ua cov raj uas muaj tshuaj lom neeg tsis zoo- muaj cov nqi tsim nyog lossis kev nyab xeeb.
Cov Mechanisms Discoloration
Deg staining tshwm sim thaum cov xim sib txuas los ntawm cov txheej txheem tshuaj adsorb mus rau PTFE nto. Hlau ions-hlau ua daj-xim av, tooj liab ua xiav-ntsuab, chromium ua txiv kab ntxwv- tuaj yeem tso ua cov oxide nyias. Organic compounds los ntawm brightener decomposition los yog roj paug tuaj yeem tsim cov xim brownish residues. Cov stains no yog superficial. Lawv tsis nkag mus rau PTFE lossis hloov nws cov khoom siv kho tshuab.
Cov stain feem ntau tuaj yeem muab so lossis yaug tawm, lees paub nws qhov xwm txheej sab nraud. Yog tias cov stain tsis so tab sis lub raj nplaim tseem du thiab cov phab ntsa tuab tsis hloov pauv, cov staining yuav raug adsorbed rau hauv cov txheej txheem polymer sab nraud- tshuaj pleev ib ce tab sis tsis tu ncua.
Thermal degradation ua rau discoloration los ntawm polymer saw scission thiab oxidation. Kev kub ntxhov siab tshaj 260 degree, los yog kev ua haujlwm ntev nyob ze ntawm qhov txwv, ua rau PTFE daj, ces xim av, raws li conjugated ob daim ntawv cog lus hauv cov pob txha polymer. Qhov tseeb thermal degradation yog nrog los ntawm kev txo cov khoom siv kho tshuab. Lub raj tsis muaj xim zoo li tawv tawv, tuaj yeem pom qhov micro- tawg, thiab txo lub zog tensile thiab elongation.
Cov tshuaj tua kab mob ua rau cov xim tsis muaj xim raws li cov qauv polymer yog hloov kho. Muaj zog txo cov neeg ua haujlwm, nws yog xim hlau sodium, lossis qee cov organic tebchaw tuaj yeem tshem tawm cov fluorine atoms ntawm cov saw, tawm hauv cov pa roj carbon - nplua nuj, tsaus nti. Tshuaj tua kab mob yog nrog los ntawm qhov chaw roughening, poob ntawm txhua yam kev ncaj ncees, thiab feem ntau yog ib qho kev hloov ntawm lub raj qhov ntev.
Table 1: PTFE Tube Discoloration Diagnosis
| Hom Discoloration | Xim | Qauv | Nto Texture | So Test | Mechanical Properties | Pom zoo ua |
|---|---|---|---|---|---|---|
| Hlau staining | Yellow-txiv kab ntxwv | Patchy, feem ntau nyob ze cov kab dej | du | So ib nrab los yog tag nrho | Ib txwm | huv si; tsis xav hloov |
| Organic residue | Brown, tacky | Uniform los yog streaked | Tej zaum yuav xav tias nplaum me ntsis | So nrog hnyav | Ib txwm | Ntxuav nrog cov kuab tshuaj sib haum |
| Chromium staining | Yellow -ntsuab | Uniform, tsaus muag | du | Tsis so yooj yim | Ib txwm | Tshuaj pleev ib ce; tsis xav tau kev nqis tes ua |
| Tsawg thermal raug | daj ntseg daj | Hnav khaub ncaws | du | Tsis so | Txo me ntsis elongation | Txo qhov kub thiab txias; saib xyuas |
| Cov thermal degradation hnyav | Tsaus xim av | Hnav khaub ncaws | Rough, micro- tawg | Tsis so | Txo lub zog loj heev | Hloov cov raj; tshawb nrhiav vim li cas |
| Tshuaj tua kab mob | Variable, feem ntau patchy | Ntawm thaj chaw tiv tauj tshuaj | Rough, pitted | Tsis so | Txo | Txheeb xyuas cov tshuaj lom neeg; hloov cov raj |
| UV raug (tsis yog- ntu ntu) | Dawb dawb | Tsuas yog saum cov kua dej | Hmoov nplej | Hmoov tawm | Me ntsis degradation | Tiv thaiv los ntawm UV; tau txais kev txhawb nqa |
Kev soj ntsuam cuam tshuam
Cosmetic staining los ntawm cov hlau ions lossis cov organic residues muaj qhov cuam tshuam tsis zoo rau kev hloov hluav taws xob. Cov txheej stain yog angstroms mus rau microns tuab - deb dua li cov txheej txheem thermal ciam teb. Tag nrho U- tus nqi tsis cuam tshuam. Tubes nrog cov tshuaj pleev ib ce tuaj yeem txuas ntxiv hauv kev pabcuam yam tsis muaj kev cuam tshuam.
Muaj tseeb thermal lossis tshuaj degradation txo cov raj phab ntsa thickness los yog nws cov neeg kho tshuab kev ncaj ncees. Txawm hais tias qhov hloov pauv cua sov zoo li qub, cov raj degraded tau txo qhov tawg ntawm qhov siab. Ib lub raj uas tau poob 30% ntawm nws lub zog tensile vim thermal degradation yuav ua tsis tiav nyob rau hauv ib tug siab excursion uas ib tug noj qab nyob zoo raj yuav ciaj sia.
Qhov kev ntsuam xyuas kev ua tau zoo yog qhov thib ob ntawm qhov kev ntsuam xyuas kev ncaj ncees. Yog hais tias cov xim tsis muaj xim yog nrog los ntawm kev txo cov phab ntsa tuab, qhov tawg ntawm qhov chaw, lossis ib qho kev ntsuas qhov poob ntawm lub zog tensile hauv cov qauv, cov hlab yuav tsum tau hloov tsis hais txog qhov kev ua haujlwm kub tam sim no.
Kev Tiv Thaiv Kev Tiv Thaiv
Hlau thiab chromium staining tuaj yeem txo los ntawm kev tswj cov hlau yaj hauv cov txheej txheem da dej. Yog hais tias qhov staining qhov chaw yog lub tshav kub exchanger nws tus kheej - metallic exchanger upstream - staining yuav ploj zuj zus tom qab hloov mus rau PTFE thoob plaws hauv lub cev.
Thermal degradation yog tiv thaiv los ntawm kev tswj qhov kub thiab txias nyob rau hauv PTFE lub rated txwv thiab tsis txhob steam superheat. Lub desuperheater lossis siab-txo lub valve kom ntseeg tau tias qhov kub ntawm qhov kub tsis dhau qhov ntsuas qhov sib hloov pauv.
Tshuaj tua kab mob tiv thaiv los ntawm kev txheeb xyuas cov txheej txheem chemistry compatibility ua ntej tshaj tawm cov tshuaj tshiab thiab los ntawm kev tshawb xyuas cov txheej txheem hloov pauv thaum muaj xim daj.
Cov ntsiab lus
PTFE heat exchanger tube discoloration muaj xws li los ntawm tsis muaj teeb meem nto staining mus rau loj degradation. Kev kuaj mob yog ua raws li xim, qauv, kev ntxhib los mos ntawm lub ntsej muag, so cov txiaj ntsig kev xeem, thiab - thaum tsis ntseeg siab - kev ntsuam xyuas cov cuab yeej cuab tam. Cosmetic staining tsis cuam tshuam rau kev ua haujlwm lossis kev ncaj ncees. Degradation uas hloov cov cuab yeej cuab tam yuav tsum tau hloov lub raj.
Kev tiv thaiv muaj xws li kev tswj cov txheej txheem paug, tswj qhov kub thiab txias tsis pub dhau qhov txwv, thiab txheeb xyuas cov tshuaj sib raug zoo. Ib lub raj uas tsuas yog stained yog kev nyab xeeb; ib lub raj uas discolored thiab embritted tsis yog.
Kev txhawb nqa engineering rau PTFE tube discoloration kev soj ntsuam muaj nyob rau thaum xa cov duab, cov ntaub ntawv txheej txheem chemistry, kev ua haujlwm kub keeb kwm, thiab kev ntsuas ntawm phab ntsa tuab lossis cov khoom siv kho tshuab.
