Analyze the difference between soft seat butterfly valve and metal seat butterfly valve

Butterfly valve is also called flap valve, which is widely used. It is generally installed on the pipelines for conveying various corrosive and non corrosive fluid media in gas, natural gas, liquefied petroleum gas, hot and cold air, chemical smelting and other engineering systems, to regulate and cut off the flow of medium. There are many types of butterfly valves, and different types of butterfly valves have different purposes. Butterfly valves can be divided into soft seal butterfly valves and hard seal butterfly valves according to the sealing form. Although there is only one word difference between the two types of butterfly valves, there are great differences in structural materials, application fields, etc. This article will analyze the difference between soft seal butterfly valve and hard seal butterfly valve.
 
One side of the sealing pair of the soft seat butterfly valve is made of metal materials, and the other side is made of elastic non-metal materials, generally be rubber and tetrafluoroplastic. The combination of the sealing materials makes the soft seat butterfly valve have good sealing performance, but it is not resistant to high temperature, easy to wear and has short service life.
Both sides of the sealing pair of the metal seat butterfly valve are made of metal materials. Metal and metal sealing make the sealing performance of metal seat butterfly valve is not good, however, it is resistant to high temperature, compression and wear, and has a long service life.
 
The sealing seat of soft seat butterfly valve is made of rubber or tetrafluoroplastic, with excellent sealing performance and zero leakage, but its service life is relatively short, it is not resistant to high temperature, and it is not suitable for some medium pipes with strong corrosion. The sealing seat of the hard seal butterfly valve is made of metal material, with relatively poor sealing performance, but it is wear-resistant and has strong compression resistance, which is suitable for the medium pipeline with strong corrosion
 
Except the differences on the sealing surface, other differences between the soft seat butterfly valve and the metal seat butterfly valve are as follows:
1. Soft seal butterfly valves are mostly of centre-pivoted butterfly valve. Hard seal butterfly valves are mostly single eccentric, double eccentric and triple eccentric butterfly valve
2. Soft seal butterfly valve is suitable for normal temperature environment. Hard seal butterfly valve can adapt to the environment of low temperature, normal temperature and high temperature
 
3. Soft seal butterfly valve is suitable for low pressure and atmospheric pressure environment. Hard seal butterfly valve is not only suitable for low pressure and atmospheric pressure, but also suitable for medium and high pressure working conditions.
4. As mentioned above, the sealing performance of the soft seat butterfly valve is better than that of the metal seat butterfly valve. But now in order to make the metal seat butterfly valve adapt to more working conditions, the triple eccentric metal seat butterfly valve with special technology has been invented, which can also maintain good sealing under high pressure and high temperature environment.
5. The soft seat butterfly valve is suitable for the two-way opening and closing of the ventilation and dust removal pipeline and the treatment of the regulating water, light industry, petroleum, chemical industry and other industries.Hard seal butterfly valve is mainly used for heating, gas supply, gas, oil, acid and alkali environment.