Hom dej nres
Glycolic kua
Feem ntau ntawm cov dej nres siv nyob rau hauv cov tsheb niaj hnub no yog raws li glycols thiab polyglycols nrog rau qhov sib ntxiv ntawm me me ntawm cov khoom hloov kho. Glycols yog dihydric cawv uas muaj cov txheej txheem tsim nyog rau kev ua haujlwm hauv hydraulic nres.
Nws thiaj li tshwm sim hais tias ntawm ntau qhov kev faib tawm tau tsim nyob rau hauv cov koom haum sib txawv, ib qho txawv ntawm American Department of Transportation (DOT) tau pib hauv paus. Txhua qhov yuav tsum tau ua rau DOT-cim nres cov kua dej tau piav qhia hauv FMVSS No. 116.
Tam sim no, peb hom tseem ceeb ntawm cov dej nres yog siv rau cov tsheb ua haujlwm hauv Lavxias Federation.
- DOT-3. Nws muaj 98% glycol puag, qhov seem 2% yog nyob ntawm additives. Cov dej nres no tsis tshua siv niaj hnub no thiab tau yuav luag tag nrho los ntawm cov tiam tom ntej ntawm DOT kab. Nyob rau hauv ib lub xeev qhuav (tsis muaj dej nyob rau hauv lub ntim) nws boils tsis ntxov dua ua ntej mus txog qhov kub ntawm +205 ° C. Ntawm -40 ° C, viscosity tsis tshaj 1500 cSt (tsim txaus rau kev ua haujlwm ntawm lub tshuab nres). Nyob rau hauv lub xeev humid, nrog 3,5% dej nyob rau hauv ntim, nws muaj peev xwm boil twb kub ntawm +150 ° C. Rau cov niaj hnub nres systems, qhov no yog ib tug ncaj tsawg pib. Thiab nws yog qhov tsis tsim nyog siv cov kua no thaum lub sijhawm tsav tsheb, txawm tias tus kws tsim tsheb tso cai rau nws. Nws muaj ib qho kev tawm tsam tshuaj lom neeg uas muaj feem xyuam rau cov xim thiab cov kua roj vanish, nrog rau cov khoom yas thiab roj hmab tsis tsim nyog rau kev ua haujlwm nrog glycol hauv paus.
- DOT-4. Nyob rau hauv cov nqe lus ntawm tshuaj muaj pes tsawg leeg, qhov piv ntawm lub hauv paus thiab additives yog kwv yees li tib yam li rau yav dhau los tiam kua. DOT-4 kua muaj qhov kub nce ntxiv hauv daim ntawv qhuav (tsawg kawg +230 ° C) thiab hauv daim ntawv ntub dej (tsawg kawg + 155 ° C). Tsis tas li ntawd, tshuaj aggression yog me ntsis txo vim yog additives. Vim yog qhov tshwj xeeb no, cov chav kawm ua ntej ntawm cov kua dej tsis pom zoo siv rau hauv cov tsheb uas lub braking system yog tsim los rau DOT-4. Raws li kev ntseeg nrov, sau cov dej tsis raug yuav tsis ua rau lub cev tsis ua haujlwm tam sim ntawd (qhov no tsuas yog tshwm sim thaum muaj kev puas tsuaj loj lossis ze-tseem ceeb), tab sis tuaj yeem txo qis lub neej ntawm cov khoom siv ntawm lub nres nres, xws li tus tswv thiab qhev cylinders. Vim muaj cov khoom siv nplua nuj ntxiv, qhov tso cai viscosity ntawm -40 ° C rau DOT-4 tau nce mus rau 1800 cSt.
- DOT-5.1. High-tech brake kua, lub ntsiab sib txawv ntawm uas yog tsawg viscosity. Ntawm -40 ° C, kinematic viscosity tsuas yog 900 cSt. DOT-5.1 cov dej hauv chav kawm yog siv feem ntau hauv cov tshuab nres tsheb, qhov twg yuav tsum tau teb ceev tshaj plaws thiab raug. Nws yuav tsis boil ua ntej nws nce mus txog +260 ° C thaum qhuav, thiab yuav nyob ruaj khov mus txog +180 ° C thaum ntub. Nws tsis pom zoo rau kev sau cov tsheb pej xeem uas tsim los rau lwm cov qauv ntawm cov dej nres.
Txhua glycol-raws li kua yog hygroscopic, uas yog, lawv khaws noo noo los ntawm huab cua nyob rau hauv lawv ntim. Yog li ntawd, cov kua dej no, nyob ntawm qhov ua tau zoo thiab kev ua haujlwm, yuav tsum tau hloov pauv ib zaug txhua 1-2 xyoos.
Qhov tsis muaj tseeb ntawm cov dej nres niaj hnub no feem ntau siab dua li tus qauv xav tau. Qhov no yog qhov tseeb tshwj xeeb tshaj yog rau cov khoom siv hauv chav kawm DOT-4 feem ntau los ntawm ntu hwm.
DOT-5 Silicone Brake Fluid
Lub hauv paus silicone muaj ntau qhov zoo dua li cov tsoos glycol puag.
Ua ntej, nws tiv taus qhov kub tsis zoo thiab muaj viscosity tsawg ntawm -40 ° C, tsuas yog 900 cSt (tib yam li DOT-5.1).
Qhov thib ob, silicones tsis tshua muaj dej tsub zuj zuj. Yam tsawg kawg nkaus, cov dej hauv silicone nres cov kua dej tsis yaj zoo li thiab feem ntau precipitates. Qhov no txhais tau hais tias qhov tshwm sim ntawm kev npau taws tam sim ntawd yuav qis dua. Vim tib yam, kev pab cuam lub neej ntawm cov kua silicone zoo mus txog 5 xyoos.
Thib peb, cov yam ntxwv ntawm qhov kub thiab txias ntawm DOT-5 kua yog nyob rau theem ntawm thev naus laus zis DOT-5.1. Kub taw tes hauv lub xeev qhuav - tsis qis dua + 260 ° C, nrog cov ntsiab lus ntawm 3,5% dej hauv ntim - tsis qis dua + 180 ° C.
Qhov tsis zoo tseem ceeb yog qhov tsis muaj viscosity tsawg, uas feem ntau ua rau muaj qhov tsis zoo txawm tias hnav me ntsis lossis kev puas tsuaj rau cov ntsaws ruaj ruaj.
Qee cov kws tsim tsheb tau xaiv los tsim cov tshuab nres rau cov kua dej silicone. Thiab nyob rau hauv cov tsheb no, txwv tsis pub siv lwm cov bunkers. Txawm li cas los xij, cov kua nplaum silicone tuaj yeem siv yam tsis muaj kev txwv loj hauv cov tsheb tsim rau DOT-4 lossis DOT-5.1. Nyob rau hauv cov ntaub ntawv no, nws yog ntshaw kom tshem tawm tag nrho cov system thiab hloov cov ntsaws ruaj ruaj (yog tias ua tau) los yog qub, hnav-tawm qhov chaw nyob rau hauv lub rooj sib txoos. Qhov no yuav txo tau txoj hauv kev tsis muaj xwm txheej ceev vim qhov tsis muaj viscosity ntawm silicone nres cov kua.
