O-ring is a common seal that is widely used in various industrial and mechanical fields. Dongsheng seals tell you that its main function is to provide static and dynamic seals to prevent fluid leakage. However, choosing and using the right O-ring is not a simple task, and many factors need to be considered, such as working pressure, working temperature, sealing medium, speed of movement, and installation environment. This article will explain in detail how to select and use the appropriate O-ring.

 Part One: O-ring material
 
The material choice of the O-ring is crucial to its performance. Different materials have different characteristics, such as high temperature resistance, corrosion resistance, wear resistance, etc., so it is necessary to choose the right material according to the application environment.

 Nitrile butadiene rubber (NBR) : Nitrile butadiene rubber is a widely used O-ring sealing material with good oil, water and corrosion resistance. It is suitable for most conventional liquid and gas sealing applications.

Fluororubber (FKM) : Fluororubber has excellent high temperature resistance, corrosion resistance and oil resistance, suitable for sealing corrosive media, such as strong acid, strong alkali and so on.

Silicone rubber (VMQ) : Silicone rubber has excellent high temperature resistance, oxidation resistance and aging resistance, suitable for sealing high temperature or long time use applications.

Polytetrafluoroethylene (PTFE) : polytetrafluoroethylene has excellent corrosion resistance and low coefficient of friction, suitable for sealing corrosive media, such as strong acids, alkali or high temperature and high pressure environments.

When selecting materials, it is necessary to consider the working temperature, sealing medium, working pressure, and whether special properties such as corrosion resistance or wear resistance are required.

The second part: O-ring size selection

Size is one of the important factors in selecting O-ring seals. First of all, it is necessary to determine the pipe diameter and flange size of the required seal, and then select the corresponding O-ring according to these dimensions. In addition, it is also necessary to consider the section height and wire diameter of the O-ring, which will affect the sealing effect.

l Pipe diameter: Select the appropriate O-ring diameter according to the diameter of the pipe to be sealed. Generally, the diameter of the O-ring should be slightly larger than the diameter of the pipe to ensure a good sealing effect.

l Flange size: According to the size of the flange select the appropriate size of the O-ring seal. To ensure that the O-ring and flange groove fit well, neither too tight nor too loose.

l Section height: The section height of the O-ring should match the depth of the flange groove. If the section height is too low, it will lead to poor sealing effect; If the section height is too high, it may cause excessive compression, resulting in damage to the seal ring.

l wire diameter: The wire diameter determines the strength and wear resistance of the O-ring. Too small wire diameter will lead to the sealing ring easily damaged, too large wire diameter will cause too much compression, affecting the sealing effect.

When choosing the size, it is also necessary to consider factors such as working pressure, working temperature and the nature of the sealing medium.

Part three: The working environment of O-type sealing ring

When selecting the O-ring, it is necessary to consider its working environment. For example, if there are corrosive media or high temperatures in the working environment, corrosion and high temperature resistant materials should be selected. If it is necessary to maintain the seal during high-speed movement, materials with good wear resistance should be selected.

Corrosive media: Working in corrosive media will lead to the gradual degradation of the O-ring, so it is necessary to choose a corrosion-resistant material, such as fluororubber or teflon.

High temperature environment: High temperature will lead to the aging and damage of the O-ring, so it is necessary to choose high temperature resistant materials, such as silicone rubber or some special formulations of nitrile rubber.

High-speed movement: In high-speed movement, the O-ring needs to withstand greater friction and wear, so it is necessary to choose materials with better wear resistance, such as nitrile butadiene rubber or polytetrafluoroethylene.

Vacuum environment: In a vacuum environment, the O-ring needs to withstand a large pressure difference, so it is necessary to choose a material with good airtight properties, such as nitrile or fluorine rubber.

Chemical reaction: Some chemical reactions will destroy the structure of the O-ring, so the impact of chemical reactions needs to be considered when selecting materials. For example, certain acids or bases can destroy the structure of teflon.

Other factors: Other factors need to be considered when selecting O-ring seals, such as working pressure, working frequency, etc. These factors will affect the service life and performance of the O-ring.

Part IV: Installation of O-ring

The following points should be noted when installing the O-ring:

l Ensure that the installation surface is clean: the installation surface of the O-ring should be cleaned before installation to prevent impurities from affecting the sealing effect. Solvents such as alcohol or acetone can be used for cleaning. This ensures that the O-ring will not be damaged by impurities during installation, thus affecting its sealing performance.

l Use the appropriate lubricant: During the installation process, some lubricants such as silicone oil or glycerin can be used to reduce the friction coefficient and improve the installation efficiency, but also to avoid damage to the O-ring, but it should be noted that the lubricant should not be too much to prevent leakage. Proper lubrication can reduce friction and improve installation efficiency, while also avoiding damage to the O-ring during installation. It should be noted that too much lubricant should not be used, otherwise it may cause leakage.

Correct placement of the O-ring: When placing the O-ring, ensure that the section height matches the groove size and ensure that there is no distortion or deformation. If the section height of the O-ring is too low, gaskets can be added to adjust the height. If the section height is too high, it may cause excessive compression resulting in seal damage. The correct placement can ensure that the O-ring can maintain the correct shape and position in the work, so as to better play its sealing performance. If the cross section height of the O-ring is too low, gaskets can be added to adjust the height to avoid excessive compression resulting in seal damage.

Use the right tools: In the installation process should use the right tools such as rubber mallet or wood mallet to avoid damage to the O-ring and improve the installation efficiency. The use of appropriate tools can avoid O-ring damage during installation, but also can improve the installation efficiency.

Note the installation direction: If the O-ring is directional, pay attention to the correct direction. For example, some O-rings with fabric reinforcement or metal skeleton require a specific installation direction to ensure that they work properly. The correct installation direction can ensure that the O-ring can work normally in the work, and avoid the deterioration of sealing performance or other problems caused by reverse installation.

Reasonable control of the compression amount: During the installation process, the compression amount of the O-ring should be reasonably controlled to ensure that it maintains a proper shape and position under working conditions. If the compression amount is too small, it will lead to poor sealing performance. If the compression amount is too large, it will lead to too much friction and wear, which affects the service life. Reasonable control of the amount of compression can ensure that the O-ring in the working process to maintain the right shape and position, but also can extend its service life.

Avoid excessive bending: Excessive bending of the O-ring should be avoided during installation to prevent its deformation or damage. If the O-ring is subjected to excessive bending, it may cause deformation or damage, which will affect its sealing performance. Therefore, excessive bending of the O-ring should be avoided during installation.

Part V: Service life and maintenance of O-ring

The following points should be noted when using O-rings:

Regular inspection: The use of the O-ring should be checked regularly, and it should be replaced in time if wear or aging is found. The inspection period can be determined according to the specific application, and it is generally recommended to check at least once a year.

Keep the sealing environment: Keep the sealing environment of the O-ring dry, clean and free of corrosive media. In wet or polluted environments, O-rings are prone to moisture, aging or corrosion, which affects their service life.

Maintenance: If the O-ring is worn or aged, its service life can be extended by adjusting the working pressure or changing the material. For some special application environments, such as high temperature, high pressure or corrosive media, more frequent inspection and maintenance may be required.

l Replacement frequency: Generally speaking, the service life of the O-ring is limited, and it needs to be replaced according to the actual situation. If the use time is too long, it may lead to reduced sealing performance, and even leakage phenomenon. Therefore, it is recommended to replace the worn or aged O-ring in time for routine inspection.

Storage conditions: Unused O-ring should be stored in a dry, cool, ventilated place, away from direct sunlight and high temperature. Storage time is too long may cause O-ring aging or performance degradation, so it is recommended to check before use.