Tam sim no, cov zis ntawmcov yeeb nkab vuamnce me ntsis, qhov kev ua haujlwm ntawm cov yeeb nkab welded Hoobkas txo qis me ntsis, kev txaus siab rau kev ua lag luam tsis zoo, thiab cov khoom muag hauv lub Hoobkas nce siab sib xws. Raws li kev sib kis tseem txuas ntxiv mus, qhov kev thov downstream thiab terminal nyuaj rau txhim kho, thiab kev lag luam lig tsis muaj zog, tab sis kuj muaj cov xwm txheej ntawm qhov kawg ntawm lub xyoo kom ua tau raws li lub sijhawm kawg, kev rov ua dua downstream. Hauv kev xaus, nws xav tias cov nqi yeeb nkab welded hauv tsev yuav tseem tsis muaj zog ua haujlwm hnub no.