Structure and Features of Butterfly Valve
Basic structure and features
1) Small structural length, compact in shape.
2) Lightweight for easy installation and disassembly.
3) Compared to other types of valves, the larger the size, the more affordable the price tends to be.
4) The valve disc will still exert resistance on the fluid even when fully open.
5) Central and eccentric types
a. The pivot center of the butterfly valve's disc is located on the axis of the sealing surface. Structurally, there is only one type of soft (elastomer, mainly rubber) seat. During opening and closing, the disc remains in contact with the upper and lower parts of the seat.
b. The double eccentric butterfly valve's disc sealing surface is centered off the valve stem's axis and also off the diameter center. Consequently, once a certain opening degree is reached, the disc will disengage from the valve body seat. In the sealing structure, due to the use of a press-fit seal, rigid valve seat materials can be employed, thus suitable for high-pressure ratings.
Instructions
1) The valve is typically used for full open and full close positions, and can also be operated at intermediate openings for flow regulation purposes.
2) Center-mounted butterfly valves are used for on/off control, while off-center butterfly valves are suitable for flow or pressure control, etc.
3) Due to potential air gap occurrence under intermediate opening conditions, please use it after fully researching the operating conditions.
4) Since the valve disc remains in the piping, during valve opening and closing, if there is a significant pressure difference in the fluid, an unbalanced torque will be generated on the valve disc (due to the pressure difference before and after the valve disc and the flow rate, etc.). The valve disc may rotate. When operating with a lever, it is essential to ensure precise alignment with the indexing disk.
5) Valve seats are typically made of rubber or TEFLON®, but due to temperature limitations, it's essential to pay attention to the pressure-temperature rating.
