By nominal diameter
(1) small diameter valve: nominal diameter DN ≤ 40mm valve.
(2) in the diameter of the valve: Nominal diameter DN 50 ~ 300mm valve.
(3) large diameter valve: Nominal valve DN is 350 ~ 1200mm valve.
(4) Extra large diameter valve: nominal diameter DN ≥ 1400mm valve
By structural features
The structural features of the valve is based on the direction of movement of the closure relative to the valve seat can be divided into:
(1) cut-off form: the closure moves along the center of the valve seat; such as the valve
(2) cock and spherical: the closure is a plunger or ball, rotating around its own center line; such as plug valves, ball valves
(3) Gates: Closure moves along the vertical seat center; such as gate valve, gate and so on
(4) Turn-on: closed pieces around the seat outside the axis of rotation; such as swing-type check valve
(5) butterfly: the closure of the disc, rotating around the seat within the shaft; such as butterfly valve, butterfly check valve, etc.
(6) Sliding valve: The closing piece slides in a direction perpendicular to the passage. Such as slippery
