O-ring is a type of sealing product with a simple external structure, a wide variety of specifications, and a large quantity required. O-ring is a rubber product with a circular cross-sectional area. Its applications cover various fields such as chemical engineering, machinery, coal, petroleum, metallurgy, transportation, household appliances, etc. O-type seal is the sealing component with the largest production quantity and widest application among all rubber sealing products.

The sealing quality and service life of O-ring depend on dimensional accuracy and rubber material. Generally, the rubber material is required to have certain mechanical strength, tear resistance, good heat resistance, oil resistance, chemical resistance, and a small compression permanent deformation under usage conditions, which are its main indicators.

According to the requirements of the operating conditions, there are generally heat and oil resistance requirements, and nitrile rubber is the most commonly used rubber material.

For oil resistant sealing products that require high temperatures (such as 150-190 ℃), acrylic rubber can be used. Fluorine rubber and heat-resistant silicone rubber are used for oil resistant rubber products that require higher temperatures.

When working under high pressure, the method to increase the hardness of O-ring rubber is to increase the filling amount of carbon black. However, if the filling amount is too high, it will be difficult to mix and damage the basic physical properties of the vulcanized rubber, making the rubber prone to burning.

Therefore, when using the same type of rubber, such as nitrile rubber, to improve heat and oil resistance and reduce compression set, peroxide (such as using DCP) vulcanization system or effective sulfur vulcanization system (low sulfur and high acceleration) can be used. These two vulcanization systems can generate more carbon carbon bond cross-linking structures and single sulfur bond cross-linking structures, effectively improving the heat and oil resistance of the vulcanized rubber and reducing compression set.

In the filling and reinforcing system of the heat-resistant and oil resistant rubber formula of the O-ring seals, the low activity hot cracking carbon black, spray carbon black or semi reinforced carbon black are mostly used. These carbon black are characterized by coarse particles, good rubber elasticity, low heat generation, low compression set, and can be filled in large quantities to reduce the cost of the rubber. If the O-ring is used under dynamic sealing conditions, it is necessary to increase its tear resistance, and some highly active and wear-resistant carbon black can be used in combination.

The fluororubber compound is a self reinforcing rubber. If the active carbon black is filled, the mechanical properties of the compound will be reduced. Therefore, it is generally filled with a small amount of coarse particle hot cracking carbon black or spray carbon black with low activity.

Advantages of O-ring seals:

1. Simple structure, small size, and compact installation location.

2. It has a self sealing effect and does not require periodic adjustment.

3. Good sealing performance, no leakage during static sealing.

4. Low frictional resistance during movement, suitable for situations with alternating pressure.

5. The size and groove have been standardized, the price is cheap, the product is easy to obtain, and it is convenient to use and purchase.

6. Strong adaptability and wide range of applications.