Nitrile rubber: Nitrile rubber is a universal sealing m […]
Nitrile rubber is a universal sealing material. It is a rubber synthesized from acrylonitrile and butadiene. It has good resistance to the following media.
The nitrile rubber seal also allows the bearing to run for a short time without oil. The allowable operating temperature range is -40 to 100°C. It can withstand temperatures up to 120°C within a short period of time. However, it is not suitable to operate at higher and higher temperatures, because the nitrile rubber will harden.
Hydrogenated nitrile rubber
Hydrogenated nitrile rubber is more resistant to high temperatures than nitrile rubber, so seals made of this material have an increasingly longer working life. In addition, hydrogenated nitrile rubber has increasingly stronger resistance to heat, aging and hardening in hot oil or ozone. The maximum allowable working temperature of hydrogenated nitrile rubber is 150°C, which is much higher than the working temperature of nitrile rubber.
The most important characteristics of fluorine rubber are high temperature resistance and chemical resistance, and it has very good anti-aging and ozone resistance, so the degree of air permeability is also very low. Even under very harsh working conditions, fluorine rubber still has excellent wear resistance. It can withstand operating temperatures of 200°C or below. The seal made of this material allows the bearing to run for a short time without oil.
Fluorine rubber also has excellent resistance to various media including oils and hydraulic oils, fuels, lubricants, inorganic acids, aliphatic hydrocarbons and aromatic hydrocarbons. In the presence of esters, ethers, ketones, certain amines and high-temperature anhydrous hydrogen fluoride and other compounds, fluorine rubber should never be used. If the seals made of fluorine rubber are exposed to open flames or high temperatures exceeding 300°C, they will endanger health and the environment! Even after cooling, they are dangerous.
The role and characteristics of the seal
The seal is very important for the cleaning of the lubricant and the service life of the bearing.
The function of the seal is to prevent the loss of lubricant and prevent contaminants from entering the space that needs to be protected.
The seal has the following characteristics:
Has sufficient deformability to compensate for absolutely irregular surfaces
Have enough strength to withstand the pressure of work
Able to withstand a relatively large operating temperature range
Minimal friction, frictional heat and wear during operation
Bearings with dust caps or seals on both sides are already filled with grease, so they generally do not require maintenance.
Bearings with dust cover are suitable for applications under dry conditions and fairly clean working conditions. The dust cover is also suitable for applications that require low friction, such as high speed or high temperature.
The dust cover is generally made of metal.
Bearings with contact seals are suitable for applications with general pollution, moisture or humidity, or working conditions that require a relatively long service life and long-term maintenance-free. The seal is generally made of rubber.