Butterfly valves are  butterfly valves because they look like butterflies. Butterfly valves can divide into different types from various aspects.

1. Structurally, it can be divided into three types:

• Concentric butterfly valves: Concentric butterfly valve is a middle rod. Enveloped a butterfly plate is by the middle of a shaft to switch the disc because the middle shaft is straight. Its seal will squeeze to the rubber on both sides when in use will put it in place.
• Double eccentric butterfly valves: Double eccentric butterfly valve point is in the middle of the plate sealing surface bevel eccentric, and the seat is partial. Butterfly plate sealing surface can quickly separate from the seat cone when opening and closing. When the valve axis clockwise rotation, butterfly plate to close the direction of movement. When the valve axis clockwise rotation 90°, butterfly plate sealing surface and valve seat sealing surface in complete closed state. Forward pressure using the principle of double eccentricity at this time the butterfly plate under the action of medium pressure will be more and more tight.
• Triple eccentric butterfly valves: Triple eccentric than double eccentric more than a stem eccentric. The eccentric mainly plays the role of stabilizing the seat and disc.

2. The connection is divide into three types: Wafer, Lug, Flange.