News Center

The difference between fluorine lined valves and rubber lined valves

First, the characteristics of fluorine lined valves

1.Excellent corrosion resistance: Fluorine plastic chemical stability is extremely high, like polytetrafluoroethylene (PTFE), can resist most of the strong acids, alkalis and oxidants. In high temperature, high concentration of strong corrosive media environment, its corrosion resistance performance is excellent.

2.Good abrasion resistance: Fluorine plastic hardness and has a self-lubricating, in the medium containing solid particles, can effectively reduce the wear and tear of the valve parts, to extend the service life.

3.Wide temperature range: Different fluoroplastic materials have different temperature tolerance range. Generally speaking, polytetrafluoroethylene (PTFE) can be used in the temperature range of -200℃ to 260℃; polyperfluoroethylene propylene (FEP) can be used in the range of -85℃ to 205℃ for normal operation. This makes the fluorine lining valve can adapt to a variety of extreme temperature conditions.

4.Excellent low coefficient of friction: The low coefficient of friction of fluoroplastics allows the valve to operate more flexible and lightweight, reducing the operating force, while reducing the wear and tear between the sealing surfaces, improving the sealing performance and service life of the valve.

5.higher pressure tolerance: Fluorine lined valves are usually able to withstand high pressure, the specific pressure tolerance depends on the structural design and manufacturing process of the valve. In general, fluorine lined ball valves, fluorine lined butterfly valves and other common types of fluorine lined valves can withstand a pressure of 1.6MPa - 6.4MPa, and some of the specially designed fluorine lined valves can even withstand higher pressures.

Second, the characteristics of rubber-lined valves

1.Good corrosion resistance: Rubber can resist the corrosion of most inorganic acids, alkalis and salt solutions. Different types of rubber, such as natural rubber, nitrile rubber, chloroprene rubber, etc., the corrosion resistance of different media varies, according to the specific conditions of the selection of the appropriate rubber material.

2.Excellent flexibility and elasticity: the flexibility and elasticity of the rubber makes the rubber lined valve can adapt to a certain degree of pipeline deformation and vibration, reduce the valve damage caused by pipeline stress. When the valve is closed, the rubber sealing surface can better fit with the valve seat to achieve good sealing effect.

3.A certain degree of abrasion resistance: Rubber has a certain degree of abrasion resistance, for the medium containing a small number of solid particles, rubber-lined valves can effectively resist the particles of the scouring wear.

4.Narrower temperature range: Generally speaking, natural rubber lined valves using temperature range between -20 ℃ and 80 ℃; nitrile rubber lined valves can be used in the temperature range of -40 ℃ to 100 ℃; neoprene rubber lined valves using temperature range of -35 ℃ to 120 ℃.

5.Relatively low pressure tolerance: Rubber-lined valves are usually suitable for low-pressure conditions, generally able to withstand the pressure between 0.6MPa - 2.5MPa. This is because the rubber material is easy to deform under high pressure, affecting the sealing performance and service life of the valve.

Third, fluorine lined valves and rubber lined valves selection principles

1.The nature of the medium First of all, consider the chemical composition of the medium, concentration, temperature, pressure and other factors. If the medium is a strong corrosive acid, alkali or oxidizer, and higher temperature, pressure, generally give priority to fluorine lined valves; if the medium is a general acid and alkali solution, the temperature and pressure is relatively low, and contains a certain amount of solid particles, rubber lined valves may be a better choice.

2.Sealing requirements According to the specific process requirements, the sealing performance of the valve to assess. Fluorine lined valves and rubber lined valves have good sealing performance, but the performance is different in different conditions. For some of the very high sealing requirements of the occasion, such as chemical production in the reactor feed valve, the valve is required to achieve zero leakage under high pressure, highly corrosive media, fluorine lined valves of high-performance sealing structure and materials to better meet this requirement. For some relatively low sealing requirements, and the medium has a certain viscosity of the occasion, such as the food and beverage industry, syrup pipeline, rubber lined valve elastic sealing surface can better adapt to the characteristics of the medium, to achieve reliable sealing.

3.Cost factors Under the premise of meeting the process requirements, the cost is also an important consideration in the selection of valves. Fluorine lined valves due to the complexity of its materials and manufacturing process, the price is relatively high; rubber lined valves are lower cost. If the project budget is limited, and working conditions allow, rubber-lined valves can be used as a priority.