Classification of butterfly valves with sealing and connection forms

According to the sealing form of butterfly valves, they can be classified into surface sealed butterfly valves and line sealed butterfly valves. The sealing performance of surface sealed butterfly valves mainly relies on the contact sealing of the sealing surface between the valve seat and the valve disc. The contact surface between the valve seat and the valve disc is usually sealed with metal hard seals or elastic materials. This butterfly valve has reliable sealing and is suitable for controlling high temperature, high pressure, and corrosive fluids; The sealing performance of the line sealed butterfly valve mainly relies on the sealing line contact seal between the valve seat and the valve disc. The contact wire between the valve seat and the valve disc is usually made of materials such as polytetrafluoroethylene and rubber. The sealing performance of line sealed butterfly valves is inferior to that of surface sealed butterfly valves, and they are suitable for low temperature, low pressure, and situations that do not require strict sealing.

There are three different ways to connect butterfly valves:

1. Welded butterfly valve: Welded butterfly valves connect the valve body and pipeline together by butt welding. This connection method has a simple and compact structure, and does not cause air leakage or loosening problems, making it suitable for fluid control at high temperatures and pressures. However, the welding connection method also has its drawbacks, mainly because the disassembly for valve maintenance is very inconvenient.

2. Flange butterfly valve: The flange butterfly valve connects the valve body and pipeline together through flange connection. Flange connections have the advantages of easy disassembly and simple maintenance, making them suitable for situations that require frequent disassembly and maintenance. In addition, the sealing performance of the concave convex sealing surface of the high-pressure flange is also very good, suitable for various high and medium pressure fields.

3. Threaded butterfly valve: Threaded butterfly valves connect the valve body and pipeline together through threaded connections. This connection method has a simple structure, easy installation, and is suitable for controlling small caliber and low-pressure fluids.

Butterfly valve is an important fluid control device that can meet the fluid control requirements under different working conditions based on its structural form, working mode, sealing form, and connection method. In practical applications, it is necessary to choose the appropriate type of butterfly valve according to the specific situation to ensure the safe and stable operation of the fluid system.