Varnish
DEFINITION
Ib qho nyias, tawv, lustrous, roj-insoluble deposit, muaj feem ntau ntawm cov organic residue, thiab feem ntau yooj yim txhais tau los ntawm cov xim siv.Nws tsis yooj yim tshem tawm los ntawm kev so nrog huv, qhuav, mos, lint-dawb so cov ntaub ntawv thiab yog resistant rau saturated cov kuab tshuaj.Nws cov xim yuav txawv, tab sis feem ntau nws tshwm nyob rau hauv grey, xim av los yog amber hues.Tau qhov twg los: ASTM D7843-18
YUAV UA LI CAS VARNISH tsim
Feem ntau, lubricants degrade nyob rau hauv kev pab cuam vim tshuaj, thermal, mechanical kev nyuaj siab uas accelerates cov tshuaj tiv thaiv ntawm cov roj oxidation thiab cov kua roj vanish tsim pib nrog oxidation.
- Tshuaj:Ntau yam tshuaj tiv thaiv tshwm sim raws li lub hnub nyoog roj.Oxidation ntawm cov roj ua rau ntau cov khoom decomposition, suav nrog insoluble particulates thiab acids.Thaum tshav kub kub thiab muaj cov khoom siv hlau (Iron, Copper) ua kom cov txheej txheem.Tsis tas li ntawd, cov roj aerated muaj ntau dua rau Oxidation.
-Thermal:Thaum cov pa npuas nkag mus rau hauv cov roj, cov roj tsis ua hauj lwm hnyav tuaj yeem tshwm sim vim yog cov xwm txheej hu ua PID (Pressure-induced Dieseling) lossis PTG (Pressure-induced Thermal Degradation).Qhov ntsuas kub hauv cheeb tsam tshaj 538 ℃ thaum huab cua npuas tau tawg nyob rau hauv siab, uas kuj ua rau thermal degradation.
-Mechanical:"Shearing" tshwm sim thaum cov roj molecules raug torn sib nrug thaum lawv ntws ntawm kev txav ntawm qhov chaw.
Polymerization tshwm sim raws li cov khoom oxidation & cov tshuaj tiv thaiv ntxiv ua ke thiab tsim cov saw ntev molecules nrog qhov hnyav dua molecular.Cov molecules no yog polarized.Tus nqi ntawm molecular polymerization nyob ntawm qhov kub thiab txias ntawm cov khoom ntawm oxidation.
Nws qhia tias muaj peev xwm yaj cov molecules hauv cov tshuaj uas cuam tshuam ncaj qha los ntawm qhov kub thiab txias.Raws li cov khoom lag luam ntawm oxidation tau tsim tas li, cov kua dej nyob ze rau qhov chaw saturation.
Tus txheej txheem lub luag hauj lwm rau deposition ntawm particulate kua roj vanish yog reversible.Feem ntau, ib zaug cov kua roj vanish, lawv tuaj yeem tau rov qab los rau hauv cov kua dej thiab tawg yog tias cov kua nplaum ntawm cov kua nplaum nce ntxiv.
Cov kua dej tsis tuaj yeem yaj cov polymerized tshiab molecules thaum lub sij hawm saturation mus txog los yog cov kua dej dhau los ntawm qhov chaw txias (Lub solubility txo qis thaum kub poob).Raws li cov khoom oxidative ntxiv tsis tuaj yeem tuav hauv kev daws teeb meem, lawv tuaj yeem tawm thiab tsim cov khoom muag (sludge / kua roj vanish).
Cov insoluble mos hais yog yooj yim rau agglomerate ib leeg thiab tsim loj polarized hais nrog ntau dua molecular hnyav.
Cov hlau yog cov polar ntau dua li cov polarized hais kom lawv yooj yim sau rau ntawm cov hlau nto (qhov chaw txias, zoo tshem tawm, tsis tshua muaj ntws) qhov twg cov txheej nplaum nplaum (Varnish) yog tsim thiab nyiam cov khoom siv ntxiv rau nws.Qhov no yog li cas cov kua roj vanish tsim
Varnish Harzds
◆Kev tuav thiab tuav cov valve
◆Overheated bearings
◆Txo qhov ua tau zoo ntawm cov khoom siv hluav taws xob
◆Ntxiv hnav ntawm cov khoom tseem ceeb thiab cov li qub
◆Shortened lifetime ntawm Machinery, lubricant, lim thiab seals
METHOD DEETECTING VARNISH
Vim qhov txiaj ntsig zoo ntawm cov kua roj vanish muaj, Koj yuav tsum tau saib xyuas cov xwm txheej ntawm cov kua roj vanish hauv koj lub lubricating system.Cov txheej txheem siv dav tshaj plaws yogMembrane Patch Colorimetry(MPC ASTM 7843) Cov.Txoj kev sim no tshem tawm cov kab mob tsis sib haum xeeb los ntawm cov qauv ntawm cov roj turbine hauv kev pabcuam mus rau thaj chaw (nrog rau 0.45µm membrane) thiab cov xim ntawm daim nyias nyias yog tshuaj xyuas los ntawm spectrophotometer.Cov txiaj ntsig tau tshaj tawm raws li ΔE tus nqi.
SOLUTIONS FOR VARNISH ROV QAB
| Qauv | Soluble Varnish | Insoluble Varnish | Dej |
|---|---|---|---|
| WVDJ | √ | √ | √ |
| WVD-II | √ | √ | |
| WJD | √ | ||
| WJL | √ |