Valve structural features can be classified according to the direction of movement of the closing element relative to the valve seat:
(1) Gate type: The closing element moves along the center of the valve seat; such as a gate valve
(2) Plug and ball type: The closing element is a plunger or ball that rotates around its own center line; such as a plug valve and a ball valve
(3) Gate type: The closing element moves along a direction perpendicular to the center of the valve seat; such as a gate valve and a gate valve
(4) Swing type: The closing element rotates around an axis outside the valve seat; such as a swing check valve and a swing check valve
(5) Butterfly type: The closing element is a disc that rotates around an axis inside the valve seat; such as a butterfly valve and a butterfly check valve and a butterfly check valve
(6) Slide type: The closing element slides in a direction perpendicular to the passage.
