Classified by nominal diameter
·Small diameter valves: valves with nominal size ≤DN40.
·Medium diameter valves: valves with nominal sizes ≥DN50~≤DN300.
·Large diameter valves: valves with nominal sizes >DN350~≤DN1200.
·Extra large diameter valves: valves with nominal size >DN1400.
Classified by nominal pressure
·Vacuum valve: a valve whose working pressure is lower than standard atmospheric pressure.
·Low pressure valve: valve with nominal pressure ≤ PN16.
·Medium pressure valve: valve with nominal pressure>PN16~≤PN100
·High-pressure valve: valve with nominal pressure >PN100~≤PN 1000.
·Ultra-high pressure valve: valve with nominal pressure > PN1000.
