Rubber o-rings are our most common rubber products, it is widely used, production technology is more simple, more application materials.
Most of the damage reasons of o-rings, as a result of the silicone seal with synthetic rubber material is belong to the viscoelastic material, so the initial amount of compression set and springback plugging ability after using for a long period of time, will produce permanent deformation and losing, eventually leak.
Permanent deformation and elastic disappear is a major cause of type O sealing ring seal performance lost.
Improper design and use will accelerate damage, leading to the loss of sealing effectiveness.
Under high pressure and high temperature working conditions, the damage is the main reason for the permanent deformation and o-rings are piled into bite spacing seal clearance and distortions during movement.
Due to the use of synthetic rubber material belongs to a viscoelastic material, so the initial amount of compression set and springback plugging ability after using for a long period of time, will produce permanent deformation and loss of function gradually, eventually leak.
Permanent deformation and elastic disappear is the main reason for the loss of sealing performance, the following is the main cause of permanent deformation.
One: the amount of compression ratio and tensile and permanent deformation o-rings used in all kinds of rubber formula, under the compression state produces compression stress relaxation phenomenon, and decreases with the increase of compressive stress over time.
Use the longer, the greater the amount of compression ratio and stretch, is produced by rubber stress relaxation and the greater the stress drop, so that the elasticity is insufficient, losing the ability to seal.
So, under the condition of allowing the use of, should try to reduce the compression ratio.
2: the relationship between temperature and permanent deformation temperature is another important factors influencing permanent deformation.
Higher temperatures will accelerate the aging of rubber materials.
The higher the working temperature, the greater the compression permanent deformation.
When permanent deformation is more than 40%, o-rings will lose the ability to seal the leakage.
3: the pressure of work medium pressure and permanent deformation medium is the main factor causing permanent deformation.
Modern hydraulic equipment work stress are increasing.
The long time of high pressure changes permanent deformation.
So when the design should be according to the working pressure to choose the appropriate pressure rubber materials.
The higher the pressure of work, the hardness of the material used and high pressure resistance should be higher.
Typically, nitrile butadiene rubber hardness is 70 degrees by default, if the pressure can choose 80 or 90 degrees.
Borui the author reminds you of silicone rubber at room temperature low tensile strength, tear resistance, abrasion resistance is poor.
General-purpose silicone rubber is compression permanent deformation is large, resistant to acid and alkali is also poor.
Recommend the use of fluorine rubber heat, acid and alkali resistant, oil resistant, resistant to hot water and steam, compression permanent deformation is small, air tightness.