DN-公称直径与管道外径对照表 DN15-ф18mm, DN20-ф25mm DN25-ф32mm, DN32-ф38mm DN40-ф45mm, DN50-ф57mm DN65-ф76mm, DN80-ф89mm DN100-ф108mm,DN125-ф133mm DN150-ф159mm,DN200-ф219mm DN250-ф273mm,DN300-ф325mm DN350-ф377mm,DN400-ф426mm DN450-ф480mm,DN500-ф530mm DN600-ф630mm,