Two different sealing forms of butterfly valves

Butterfly valve is one of the commonly used valves for pipeline valves. Because of its simple structure and convenient operation, it can form diversified control methods, such as electric butterfly valve, pneumatic butterfly valve and turbo butterfly valve, with different driving devices!

Butterfly valves are often used in applications with large calibers and flow rates, because the cost of butterfly valves can be reduced by 1.5 to 2 times compared to other valves of the same diameter, making them an economical and practical choice!

According to the sealing form of the butterfly valve, the butterfly valve can be divided into two categories, soft seal and hard seal.

Two different sealing forms of butterfly valves play different roles in their relative use of pipes. In a sense, there are still major differences! Users should choose between The difference has a detailed understanding and cognition!

For the common soft seal lining butterfly valve and metal hard seal butterfly valve, the lining butterfly valve is generally used for pipes containing corrosive medium, and the sealing effect can reach zero leakage, but only suitable for normal temperature and pressure! The relative temperature and pressure are relatively high, but the sealing and corrosion resistance are not as good as the soft sealing butterfly valve!

So what are the differences between soft-seal butterfly valves and hard-seal butterfly valves? We talk about the four aspects of structure, sealing performance, use conditions and manufacturing.

1.from the structure:

A hard seal butterfly valve means that both sides of the seal pair are made of a metal material or a harder other material. The soft sealing butterfly valve is the two sealing surfaces that can be used separately, or all of the soft materials can be used. For example, the fluorine-filled butterfly valve is a butterfly plate and the valve seat is wrapped with PTFE;

2.from the sealing performance:

The soft seal lining fluorine butterfly valve has the advantages of good sealing performance, and the disadvantages are easy aging, wear and short service life. Hard seal butterfly valves have a long service life, but the seal is relatively inferior to the soft seal.

3.from the conditions of use:

The soft sealing lining fluorine butterfly valve is used in normal temperature and normal pressure environment. The hard sealing butterfly valve can be used in low temperature, normal temperature, high temperature and other environments. Generally, it can be used for higher pressure, soft seal is not good, but the fluorine-lined butterfly valve has superior corrosion resistance!

4.from the manufacturing:

As for the manufacturing aspect, from the principle point of view, the difference between the two is not big, mainly the difference of the valve seat, the soft seal lining fluorine butterfly valve is a non-metallic structure, the hard seal butterfly valve is a metal structure, taking into account the hardness relationship between the metal, and What kind of media, etc.