Valves are various,Gate Valves. At here , i will share some knowledge about Check valve: According to the structure, can be divided into lifting check valve, swing check valve and butterfly check valve three. Lift check valve can be divided into vertical and straight-through two. Swing check valve is divided into single-valve, double-valve and multi-valve three. Butterfly check valve double Butterfly valve, butterfly single flap, the above types of check valve in the connection form can be divided into thread connection, flange connection, welding and clip-on connection of four