1. Valves hauv kev lag luam kev tiv thaiv ib puag ncig Hauv kev tiv thaiv ib puag ncig, cov khoom siv dej feem ntau yuav tsum tau siv lub nruab nrab npauj npaim valve, mos-sealed gate valve, pob valve, thiab tso pa tawm valve (siv tshem tawm cov cua hauv cov kav dej).Kev kho dej phwj tuaj feem ntau yog ...
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