What is the difference between PTFE lined butterfly valve and hard seal butterfly valve

PTFE lined butterfly valve and hard seal butterfly valve are two different types of butterfly valves, and they are very different.
VALTECCN China butterfly valve manufacturers introduce the differences as follows:

When making a choice decision, we need to clearly grasp and be aware of the similarities and differences between the two. Now, some examples will be listed for you to compare the fluorine lined butterfly valve and the hard seal butterfly valve.

PTFE lined butterfly valve

The lining material of the PTFE lined butterfly valve is fluorine plastic, and most of the materials on the market are made of polytetrafluoroethylene, and the code name is polytetrafluoroethylene. PTFE material has strong corrosion resistance and can be used in strong corrosive media, such as strong acid and alkali. At the same time, the material also has certain heat and cold resistance properties, and the adaptable temperature is between -196 and 200 °C.

Advantage

1. PTFE butterfly valve relies on the excellent performance of PTFE to effectively isolate the medium and the valve body to achieve the purpose of anti-corrosion. It has been widely used in petroleum, chemical, environmental protection and other fields.
2. The fluorine-lined butterfly valve has high cost performance under normal temperature and pressure, and can be used instead of stainless steel valve body.

Hard sealing butterfly valve

Butterfly valves with metal materials or other hard materials on both sides of the sealing ring are called “hard seals”. This seal has poor sealing performance, but has high temperature resistance, wear resistance and good mechanical properties. For example: steel+steel, steel+copper, steel+graphite, steel+alloy steel (the steel here can also be cast iron, cast steel, alloy steel or surfacing, sprayed alloy).

Advantage

1. Has high temperature resistance, wear resistance and good mechanical properties, long service life.
2. The hard sealing butterfly valve adopts precise J-shaped elastic sealing ring and triple eccentric multi-layer metal hard sealing structure, which is widely used in metallurgy, electric power, petrochemical, water supply and drainage, municipal buildings and other industrial pipelines with medium temperature below 425℃.

Structural difference

(1) Applicable conditions: The fluorine-lined butterfly valve can be used at room temperature and normal pressure, while the hard-sealed butterfly valve can be used at lower temperature, room temperature, high

1. Applicable conditions: PTFE lined butterfly valves can be used at room temperature and normal pressure, while hard-sealed butterfly valves can be used at lower temperature, room temperature, high temperature and other conditions.
2. Structural angle: The former has two contact surfaces and can be made of one or more soft materials. For example, the disc and seat of a fluorine-lined butterfly valve are wrapped in PTFE. The latter means that both sides of the sealed pair are made of metal or other hard material.
3. In terms of processing: In terms of processing, the two seem to be similar to each other in principle, mainly the valve seat. The former is a non-metallic structure, while the latter is a metallic structure. When choosing, it is necessary to comprehensively consider the relationship between its material, hardness, working conditions and suitable medium.

Differences in performance characteristics

1. The angle of sealing ability: The advantage of the fluorine-lined butterfly valve is that its sealing ability is very good, and its sealing effect can also achieve zero leakage. But the disadvantage is that it is relatively easy to age, and the application life is relatively short. The hard seal valve has a longer working time, but its sealing ability is weaker.
2. Corrosion resistance: The former is mainly used for pipelines containing corrosive media, and its corrosion resistance is also stronger than the latter.