Three types of butterfly valves?

There are many types of butterfly valves. According to their respective classification criteria, we can divide them into three main categories (from their classification perspective):
1. Classification of items according to sealing technology
Mandatory sealing measures are taken for butterfly valves
These include sealing butterfly valves with elastic design and sealing butterfly valves equipped with additional torque. The sealing pressure ratio of elastic sealing butterfly valves is determined by the elastic effect of the valve plate on the valve seat, valve seat or valve plate when the valve is closed. The sealing pressure of the torque sealing butterfly valve applied to the outside is determined by the torque applied to the valve shaft.
How butterfly valves are handled during pressurization and sealing operations
The elastic sealing part on the valve seat or valve plate generates the sealing pressure ratio by pressurization.
Butterfly valves have the characteristics of automatic sealing
The sealing pressure ratio is naturally generated by the pressure of the medium.
2. Classification according to various structural properties
Central butterfly valves are also commonly referred to as concentric butterfly valves by the public
The notable feature of this structure is that the center axis of the valve stem, the center of the butterfly plate and the center of the body are all placed in the same place. This type of material is generally a flexible sealing material, and its structure is not only simple, but also the manufacturing process is quite direct. However, the butterfly plate and the valve seat are constantly subjected to extrusion and friction, which increases the resistance distance between them and accelerates the wear rate.
This device is a single eccentric butterfly valve
A notable feature of this structure is the offset between the valve stem center and the butterfly plate center, which causes the two ends of the butterfly plate to no longer serve as the rotation center, thereby effectively dispersing and reducing the excessive extrusion between the upper and lower parts of the butterfly plate and the valve seat. However, during the switching of the valve, the friction between the butterfly plate and the valve seat in the single eccentric structure is not completely eliminated, which limits its application range in actual operation.
The butterfly valve shows eccentric characteristics on both sides
Based on the technology of the single eccentric butterfly valve, we have carried out more in-depth technical optimization and molding, and this technology has been widely adopted and practiced in many fields. The design feature of the valve stem axis is that it is neither located at the center of the butterfly plate nor at the center of the body. Thanks to the unique double eccentric design, when the valve is opened, the butterfly plate can be quickly separated from the valve seat, which greatly reduces the unnecessary extrusion and friction between the butterfly plate and the valve seat, thereby reducing the resistance and wear during opening, and also prolonging the service life of the valve seat.
In addition, based on the double eccentric butterfly valve, we have also carried out more in-depth optimization work, and finally successfully developed a three-eccentric butterfly valve, which makes its performance more outstanding.
3. Classification according to the material used for the cover
This is a butterfly-shaped soft lock valve
The sealing pair can be composed of non-metallic soft materials and non-metallic soft materials, or a fusion of metal hard materials and non-metallic soft materials. Soft-sealed butterfly valves have been widely used in gas pipelines and waterways in metallurgy, light industry, power and petrochemical systems. Its main function is to serve as a two-way switch and regulating device for ventilation and dust removal pipelines.
This valve is a solid butterfly structure made of metal
Metal hard materials and metal hard materials together form the structure of the sealing accessories. The metal hard seal butterfly valve uses eccentric metal as its main sealing structure. This special sealing method is to achieve metal sealing by metal, and can be replaced by metal sealing rings to achieve the effect of metal sealing. In addition, stainless steel plates and graphite composite plate sealing rings are also used in the field of metal sealing. The drive mode of this device includes not only electric drive, but also manual drive, worm gear drive and pneumatic drive. Double eccentric butterfly valve is a device used for metal-to-metal wire sealing. It is particularly suitable for heating, gas supply and water supply systems of gas, oil and acid-base pipelines in cities, playing a key role in regulation and throttling. Metal-to-metal face seal triple eccentric butterfly valve is not only used as a program control valve for large pressure swing adsorption (PSA) gas separation devices, but also widely used in many industries such as petroleum, petrochemical, chemical, metallurgy, and power. It is a high-quality alternative to gate valves and stop valves.
From a macro perspective, there are many different types of butterfly valves, so when making a choice, you should make a decision based on the specific operating requirements and the working environment.