Hauv kev tsim cov txheej txheem ntawm polyurethane ua ntej-insulated ncaj- cov kav dej faus, cov kav hlau yuav tsum tau ua kom sov ua ntej nkag mus rau theem foaming. Txawm hais tias cov kauj ruam no yuav tshwm sim yooj yim, nws cuam tshuam ncaj qha rau qhov kawg ntawm cov txheej txheem rwb thaiv tsev.
Polyurethane foaming yog tshuaj lom neeg cov tshuaj tiv thaiv zoo heev rau ambient kub. Tus txheej txheem kub ntau rau foaming yog 5℃mus rau 40 degree, nrog rau kev pom ntau ntawm kwv yees li 18℃to 25 degree. Yog tias cov yeeb nkab steel kub qis dhau lawm, cov foaming polyurethane tau cog lus sai sai thaum sib cuag nrog qhov chaw txias; Qhov no slows tus txheej txheem curing thiab cuam tshuam cov npuas tsim thiab kev faib tawm, uas ua rau cov npuas tsis sib xws thiab cuam tshuam kev ua haujlwm ntawm rwb thaiv tsev. Cov neeg tsim khoom tau pom tias thaum ua npuas dej ua rau lub caij ntuj no yam tsis muaj preheating, hla - ntu ntawm cov npuas dej feem ntau nthuav tawm cov ntaub ntawv tsis sib xws thiab qhov loj me ntawm tes tsis sib xws - teeb meem ncaj qha los ntawm qhov kub thiab txias.
Preheating kuj pab kom muaj zog adhesion ntawm cov npuas dej thiab cov yeeb nkab steel. Thaum lub sij hawm txau los yog nchuav ntawm cov pob txha polyurethane ua npuas ncauj, qhov kub tsis txaus ntawm lub substrate (cov yeeb nkab) txo qis zog. Cov ntaub ntawv qhia tias tsis ua raws li qhov xav tau ntawm qhov kub thiab txias ua rau cov adhesion ntawm polyurethane ua npuas ncauj thiab substrate. Nyob rau tib lub sijhawm, qhov khoob lossis qhov khoob tuaj yeem tsim ntawm cov npuas dej thiab cov yeeb nkab steel. Cov voids no cuam tshuam cov kav dej tag nrho cov qauv kev ruaj ntseg, hloov cov kev ntxhov siab uas tau ntsib los ntawm cov yeeb nkab steel thaum lub sij hawm thermal expansion thiab contraction, thiab ua rau lub neej luv luv ntawm cov txheej txheem rwb thaiv tsev. Preheating cov yeeb nkab steel ua ntej foaming yog qhov tseem ceeb los xyuas kom meej qhov kev faib tawm ntawm polyurethane ua npuas ncauj.
Preheating kub yog feem ntau tswj ntawm 40℃thiab 60 degree. Cov kub uas tsis tshua muaj tshwm sim ua tsis tiav foaming tshwm sim, ua rau nws nyuaj los lav qhov ua npuas ncauj ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom; Piv txwv li, qhov kub thiab txias ntau dhau tuaj yeem ua rau lub sijhawm ua npuas ncauj, uas tseem ua rau lub cev tsis sib xws ntawm cov txheej txheem rwb thaiv tsev. Preheating dhau los ua cov txheej txheem yuav tsum tau ua thaum qhov ntsuas kub qis dua 15 degree. Cov neeg tsim khoom feem ntau kho lawv cov txheej txheem preheating raws li cov huab cua tshwj xeeb kom ntseeg tau tias cov yeeb nkab steel kub ua tau raws li cov qauv xav tau. Preheating cov yeeb nkab steel yog ib kauj ruam tseem ceeb hauv kev ua kom cov txheej txheem rwb thaiv tsev zoo; nws lub hom phiaj yog los tswj kom muaj qhov kub thiab txias nyob ib puag ncig lub caij sib txawv, yog li ua kom cov khoom siv rwb thaiv tsev ruaj khov zoo. Yog tias cov kauj ruam no tsis tau ua kom raug, nws yog qhov nyuaj rau kev them nyiaj rau qhov tsis txaus, txawm li cas los xij, cov txheej txheem tom qab foaming, curing, thiab tshuaj xyuas tau zoo npaum li cas.