ما هي حلقات O المغلفة？

يتم استخدام الحلقات O المغلفة على نطاق واسع لفوائدها العديدة مقارنة بالأختام والحشيات الأخرى. هذه الحلقات الدائرية المصنعة خصيصًا مصنوعة من مزيج من مادتين توفر قوة إضافية وحيوية ومرونة لتحمل الظروف القاسية.

This article will discuss encapsulated O-rings, their advantages, disadvantages, and the manufacturing process. It will also help you understand the heating method used in the manufacturing of these O-rings and their different types. Stick with us till the end if you are interested in mechanics and the Encapsulated O-rings.

ما هي الحلقة O المغلفة؟

An encapsulated O-ring is a specialized seal made from a combination of two materials, consisting of two major parts, i.e., outer coat and inner core. Such seals are often used at both industrial and domestic levels to stop leakage of air, gas, or liquids through the joints.

These seals provide مرونة إضافية, endurance, stability, and chemical and temperature resistance. Though you can use any rubber O-ring or seal to do the job, using an encapsulated O-ring has its additional perks.

The double-layered o-ring is made of an outer coat, which is usually a material named تفلون، والنواة الداخلية، وهي إما سيليكون or فيتون. تقوم مادة التفلون الخارجية بتغليف اللب الداخلي، ومن ثم تعطي اسم الحلقات الدائرية المغلفة بالتفلون.

كيف تم تصنيع الحلقات المغلفة؟

The history of O-rings dates back to the 20th century, when a Denmark-born machinist, نيل كريستنسن, was working as a brake system mechanic for street cars in the US. Niel Christensen was born in 1865 in Denmark and later moved to the US in 1891.

During his job as a brake system mechanic, he tried different materials to seal the pipes and other joints for an effective braking mechanism. It was in 1936 that he found a way to install rubber seals in pistons, and just three years later, in 1939, he successfully finished the patent application.

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Types of Encapsulated O-Rings

Though the purpose of all the encapsulated O-rings is almost the same, there are minor differences in their manufacturing and design, which make their task a bit more specific.

Hollow core O-rings and Solid core O-rings are the two types of Encapsulated O-rings based on their core design. There are several other types of O-rings depending on the material used in the outer jacket and inner core, each with its unique features.

نواة صلبة

Solid core O-rings are specifically made to deal with lower temperatures. It is because their inner core is filled with a material named سيليكون أو فيتون, like the tires of a tubeless bike.

Solid core O-rings provide excellent contraction and flexibility, making them the best choice for use in Frigid temperatures. The core material also plays a major role in determining the مميزات العضوية الممتازة of the encapsulated O-ring.

The Viton inner core O-ring is well known for its flexibility and shrinking abilities, while the Silicone inner core O-ring is famous for its مقاوم للحرارة قدرة. تشتهر الحلقة الدائرية المغلفة ذات النواة الصلبة باحتفاظها بالمرونة.

المجوفه

Hollow core o-rings, as the name suggests, are hollow from the inside, like any inflatable bike tire. Hollow core O-rings are similar to solid core O-rings as both have an outer jacket made of Teflon that encapsulates the inner core, except that the former is hollow from the inside.

The outer jacket is either made of PFA or FEP, depending on the requirements and the conditions it has to survive in. On the other hand, the inner core is either جبهة مالوكو (مصنوع من مادة الفيتون) أو السيليكون، مما يمنحه القدرة الفريدة على الضغط في المساحات الضيقة. ومع ذلك، فإن هذه الحلقات الدائرية تكافح من أجل التعافي بعد الانكماش.

FEP

FEP, expanded as Fluorinated Ethylene Propylene، ليس نوعًا من الحلقات الدائرية المغلفة ولكنه مادة محددة تصنع نوعًا فريدًا من الحلقات الدائرية المغلفة. يخلط معظم الناس بينه وبين مادة التيفلون، وهي مادة أخرى تستخدم في الطلاء الخارجي للحلقات الدائرية المغلفة.

FEP also has several other names in the industry, such as Neoflon FEP, Teflon FEP, and Dyneon FEP. The numerous features of FEP-coated O-rings include low friction and resistance to temperatures ranging من -60 درجة مئوية إلى +205 درجة مئوية.

It can also remain flexible at cryogenic temperatures, showing effective cryogenic seal performance. Moreover, it is also highly resistant to corrosive chemicals, besides being non-flammable.

FEP لديه مستوى منخفض جدًا مجموعة ضغط, which shows that it can come back to its original shape after deformation. This material can help manufacture different types of O-rings, such as FEP encapsulated solid silicone, FEP encapsulated steel spring, and FEP encapsulated hollow silicone.

PFA

كوبوليمر بيرفلوروألكوكسي, abbreviated as PFA, is another material used in encapsulated O-rings. It is almost similar to FEP in all of its features, except that it is a bit more advanced and offers more resistance to temperatures (-60 °C to +260 °C).

Besides, it is resistant to a wider range of chemicals than FEP, such as petroleum, acids, naphtha, aromatic solvents, and alcohol.

PFA has higher mechanical strength, which means it can withstand high pressures and stretches. It is also resistant to cracks and high-stress conditions and is often used at an industrial level where high durability and thermal stability are required. On the contrary, it is also more expensive than FEP.

النتريل إلاستومر

إذا كنت تبحث عن حلقة دائرية مغلفة للاستخدام الشائع، مثل وصلات منع التسرب التي تتعامل مع الماء أو الزيوت أو السوائل الهيدروليكية، فإن Nitrile Elastomer هو خيارك المفضل. المعروف أيضا باسم Buna-N أو NBR, Nitrile Elastomer is a general-purpose rubber often used for temperature ranges of -50°C to 120°C.

Though it has good resistance to temperatures and abrasive processes, there is a high risk of damage إذا تم تجاوز الحد.

For example, substances like ketones, nitrohydrocarbons, Phosphorus esters, etc., can cause damage to the rings. Due to this, nitrile elastomers are only suitable for limited applications in automobiles, railways, sanitary, and agricultural.

حلقات فيتون س

Viton O-rings are a type of encapsulated O-ring with an FKM or Viton inner core. The outer jacket might be of PFA or FEP, depending on whether you need an FEP-encapsulated Viton core or a PFA-encapsulated Viton core. These also have excellent thermal stability within a temperature range of -40 °C to 250°C.

In a nutshell, Viton O-rings have high mechanical strength, low compression set resistance, and low gas permeability. These features make it a perfect choice for automobiles, aerospace industries, and chemical engineering industries.

Though they work fine with petroleum, acids, halogenated hydrocarbons, and silicone fluids, one should avoid contact with heated hydrofluoric acids, esters, low molecular weight amines, and Skydrol.

حلقات سيليكون

مثل الحلقات O المغلفة الأخرى، حلقات سيليكون have excellent thermal stability for temperatures ranging between -100°C and 300 300°C.

Moreover, Silicone O-rings’ specially designed inner core provides exceptional tolerance up to -115°C to 315°C for some time. This makes it an ideal choice for areas where extreme temperature fluctuations are expected.

مثل الحلقات الدائرية المغلفة الأخرى، تعمل الحلقات الدائرية المصنوعة من السيليكون بشكل أفضل أيضًا التطبيقات الساكنة.

Moreover, these O-rings are acclaimed for their flexibility and abrasion resistance. However, they only work better with water, oil, and steam. There are two types of Silicone O-rings: Hollow Silicone core and solid silicone core.