The Difference And Selection Of Fluorine-lined Butterfly Valve And Hard-sealed Butterfly Valve

The difference and selection between Lined Butterfly Valve and hard-sealed butterfly valves

As one of the most commonly used valves in process pipelines, butterfly valves are not only simple in structure and easy to operate, but also can form a variety of control methods when equipped with different drive devices, such as electric butterfly valves, hydraulic butterfly valves, pneumatic butterfly valves, etc.! Moreover, butterfly valves are often used in occasions with large calibers and flows. Compared with other valves of the same caliber, the cost can be reduced by 1.5 to 2 times, which is both economical and practical!

According to the different sealing forms of butterfly valves, they can be divided into two categories, one is soft sealing and the other is hard sealing! The two butterfly valves with different sealing forms play different roles in the relatively used pipelines. In a sense, there are still big differences! When selecting, users should have a detailed understanding and cognition of the difference between the two!

Take the most common soft-sealed fluorine-lined butterfly valves and metal hard-sealed butterfly valves as examples. Fluorine-lined butterfly valves are generally used for pipelines containing corrosive media, and the sealing effect can reach zero leakage, but they are only suitable for normal temperature and pressure! The temperature and pressure of hard-sealed butterfly valves are relatively high, but their sealing and corrosion resistance are not as good as those of soft-sealed butterfly valves!

1. From the structure: Hard-sealed butterfly valves refer to the sealing pair with both sides made of metal materials or other harder materials. For soft-sealed butterfly valves, the two sealing surfaces in contact can be made of soft materials separately or in full. For example, the butterfly plate and valve seat of fluorine-lined butterfly valves are wrapped with PTFE;

2. From the sealing performance: The advantage of soft-sealed fluorine-lined butterfly valves is good sealing performance, and the disadvantage is easy aging, wear and short service life. Hard-sealed butterfly valves have a long service life, but their sealing performance is relatively poor compared to soft seals.

3. From the use conditions: Soft-sealed fluorine-lined butterfly valves are used in normal temperature and pressure environments, while hard-sealed butterfly valves can be used in low temperature, normal temperature, high temperature and other environments. Generally, they can be used at higher pressures, but soft seals cannot, but fluorine-lined butterfly valves have super corrosion resistance!

4. From the manufacturing perspective: As for manufacturing, in principle, there is not much difference between the two. The main difference is the valve seat. The soft-sealed fluorine-lined butterfly valve is a non-metallic structure, and the hard-sealed butterfly valve is a metal structure. The hardness relationship between metals, as well as the working conditions and the medium used must be considered.