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The corrugated pipe stop valve is a specially designed stop valve. Its key feature is that a metal corrugated pipe assembly is used as the moving sealing element at the valve stem position, providing a dual guarantee compared to the traditional packing seal. This enables it to demonstrate significant advantages in many demanding working conditions.
Here are its main advantages:
1. Absolute Zero External Leakage (Zero External Leakage)
This is the most crucial and important feature of the bellows stop valve.
Traditional valves: They rely on pressing the packing (such as graphite, PTFE) to seal the valve stem. Over time, the packing will wear out and age, resulting in the leakage of the medium from the valve stem.
Bellows valve: One end of the bellows is welded to the valve stem, and the other end is welded to the valve cover, forming a dynamic sealed metal barrier. When the valve is opened or closed, the up-and-down movement of the valve stem is absorbed by the expansion and contraction of the bellows, and the medium is completely enclosed within the bellows, fundamentally eliminating the possibility of leakage through the valve stem seal. This is of crucial importance in situations where handling toxic, harmful, flammable, explosive, radioactive or expensive media is required.
2. Higher safety and environmental protection
Due to its feature of zero external leakage, it significantly enhances the safety level and environmental protection capability of the production facility.
Protecting personnel safety: It avoids the risk of operators coming into contact with hazardous chemicals or harmful gases.
Compliant with strict regulations: Meeting increasingly stringent environmental protection regulations internationally (such as EPA, TA-Luft) and the health, safety and environment (HSE) requirements of the factory.
Preventing energy and product loss: For expensive process media (such as high-purity chemicals, rare gases), zero leakage means zero waste.
3. Dual-sealing design, extremely reliable
The bellows stop valve usually adopts a "bellows + packing" dual-sealing structure.
The first seal: The metal bellows, which performs the main sealing function and isolates the medium.
The second seal: The traditional packing box. Even if the bellows ruptures due to an unexpected situation, the packing box can still serve as a backup seal for a period of time, providing buffer time for system maintenance and shutdown, significantly enhancing the safety redundancy of the system.
4. Longer service life
The corrugated tube structure protects the internal packing chamber, preventing it from being eroded, corroded and affected by high temperatures by the medium.
The packing only starts to function after the bellows fail. Therefore, the service life of the packing is extremely long, significantly reducing the frequency and cost of daily maintenance and replacement of the packing.
5. Suitable for harsh conditions
High vacuum conditions: The minor leakage of traditional fillers is unacceptable in high vacuum systems. The absolute sealing characteristic of the bellows makes it an ideal choice for high vacuum and ultra-high vacuum systems.
Extreme temperatures: Metal bellows (usually made of stainless steel or alloys) can tolerate a wider temperature range than non-metallic fillers, and perform exceptionally well in high-temperature conditions.
Corrosive medium: Different materials (such as Hastelloy, Monel, etc.) can be selected for the bellows according to the characteristics of the medium to resist corrosion.
6. Reduce life cycle cost
Although the initial purchase cost of the corrugated pipe stop valve is higher than that of the ordinary stop valve, from an overall perspective of the life cycle, its total cost may be lower.
Low maintenance cost: Reduces the number of shutdowns due to filler replacement and the associated maintenance labor and material costs.
Low safety costs: Avoids potential safety incidents, environmental pollution fines, and production halt losses caused by leaks.
Low operating cost: Prevents the loss of valuable materials.
Summary and Application Scenarios
In summary, the core advantage of the corrugated pipe stop valve lies in its use of a metal corrugated tube to achieve an absolutely zero leakage for the valve stem's dynamic seal, thereby providing outstanding safety, environmental friendliness, and reliability.
It is particularly applicable to the following key situations:
Toxic/Highly Toxic Chemicals: Such as chlorine gas, phosgene, hydrogen sulfide, etc.
Flammable and explosive media: such as hydrogen, liquefied petroleum gas (LPG), light hydrocarbons, etc.
Strongly corrosive media: such as acids, bases, etc.
High vacuum system: such as in the semiconductor, photovoltaic, and aerospace industries.
Extremely hazardous substance: radioactive material.
Precious medium: Prevent product loss.
For environments with strict requirements: Factories that need to meet strict emission standards.
When making a selection, particular attention should be paid to the material of the bellows, the welding quality, the fatigue life (usually requiring more than 10,000 opening and closing cycles), as well as the qualifications and experience of the manufacturer.
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