Views: 34731 Author: Site Editor Publish Time: 2020-04-27 Origin: Site
O-ring seals design and improper use will accelerate its damage and loss of sealing performance. Experiments show that if the design of each part of the sealing device is reasonable, simply increasing the pressure will not cause damage to the O-ring seals. What are the common wear of the O-ring seals? What causes wear and tear?
Because the synthetic rubber material used for O-ring seals seals is a viscoelastic material, the initial set compression and rebound blocking capacity will be permanently deformed and gradually lost after a long period of use, and eventually leak. Permanent deformation and loss of elasticity are the main reasons for O-ring seals loss of sealing performance. The following are the main causes of permanent deformation:
1) The relationship between compression rate and stretching amount and permanent deformation
2) Temperature affects the relaxation process of the O-ring seals
3) Medium working pressure and permanent deformation
Temperature will affect the compression set rate of O-ring seals materials.
When the deformation rate is 40% or more, leakage will occur, so the heat resistance limit of several rubber materials is: nitrile rubber 70 ° C, EPDM 100 ° C, and fluorine rubber 140 ° C. Therefore, countries have stipulated the permanent deformation of O-ring seals. O-ring seals of the same material, at the same temperature, O-ring seals with large cross-section diameters have a low compression set. If the O-ring seals is properly assembled and used properly, it is generally not easy to cause rolling or distortion in the state of reciprocating motion.
There are many causes of twist damage, the most important of which are caused by uneven gaps between pistons, piston rods and cylinders, excessive eccentricity, and uneven diameters of O-ring seals cross sections. The unevenness of hardness, lubricating oil film thickness and other factors, as well as the surface roughness of the seal shaft, cause part of the O-ring seals to slide along the surface of the workpiece, while the other part rolls, causing the O-ring seals to distort.
Movement makes the ring easily damaged by twisting, which is an important cause of damage and leakage of the sealing device. Therefore, improving the machining accuracy of the sealing groove and reducing the eccentricity are important factors to ensure the reliable sealing and life of the O-ring seals. The seal should not be installed in a twisted state. If it is twisted during installation, twist damage will occur quickly. In the work, the twisting phenomenon will cut off the O-ring seals, resulting in a large amount of oil leakage, and the cut O-ring seals will be mixed with other parts of the hydraulic system, causing a serious accident.
When the sealed gap has relative movement, dust and sand particles in the working environment are adhered to the surface of the piston rod, and are brought into the cylinder with the oil film along with the reciprocating movement of the piston rod, becoming an intrusion into the surface of the O-ring seals. Abrasive particles accelerate the wear of the O-ring seals, so that it loses its tightness. To prevent this, a dust wiper must be used at the outboard shaft end of the reciprocating seal.
Selecting a good quality O-ring seals can delay the wear phenomenon to a certain extent. Welcome to visit our official website to purchase more high-quality seals.