DN与外径兑换表大外径系列 DN15-ф22mmDN20-ф27mm DN25-ф34mmDN32-ф42mm DN40-ф48mmDN50-ф60mm DN65-ф76(73)mmDN80-ф89mm DN100-ф114mmDN125-ф140mm DN150-ф168mmDN200-ф219mm DN250-ф273mmDN300-ф324mm