Saib Loj Cov Duab Valve yog ib qho ntawm cov khoom siv tseem ceeb hauv kev tswj cov dej.Tam sim no, cov ntawv thov tseem ceeb ntawm lub valve suav nrog roj av thiab roj, hluav taws xob, tshuaj lom neeg engineering, dej thiab dej phwj kho, ntawv ua thiab metallurgy.Ntawm qhov ntawd, roj & roj, hluav taws xob thiab tshuaj lom neeg kev lag luam ...
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