The structural characteristics of valves are classified according to the direction in which the closing part moves relative to the valve seat:

(1) Gate type: the closing part moves along the center of the valve seat; such as stop valve

(2) Plug and ball type: the closing part is a plunger or a ball, which rotates around its own center line; such as plug valve and ball valve

(3) Gate type: the closing part moves along the center of the vertical valve seat; such as gate valve and gate valve

(4) Swing type: the closing part rotates around the axis outside the valve seat; such as swing check valve

(5) Butterfly type: the closing part is a disc, which rotates around the axis inside the valve seat; such as butterfly valve and butterfly check valve

(6) Sliding valve type: the closing part slides in a direction perpendicular to the channel.