Performance of hydraulic seals

The good or bad hydraulic Sealing technology will affect the working quality and lifespan of hydraulic supports. What are the normal performance of hydraulic Seal products?

Because the tensile strength of general sealing materials tends to decrease with the increase of temperature, when selecting materials, it is necessary to consider their actual mechanical strength at high operating temperatures and high temperatures. If the tensile strength is too low, it will cause a certain amount of stress relaxation or even permanent deformation, resulting in seal failure. The tensile strength is too high, and the performance requirements for the material are too strict. Therefore, when selecting materials in practice, comprehensive consideration should be given to the tensile strength of the material;

Because the sealing ability of Hydraulic Seals is mainly achieved by producing recoverable compression deformation within the sealing groove. Therefore, the selected sealing material should have small permanent deformation, strong elasticity, and high rebound force. In addition, the permanent deformation of materials is also related to temperature changes, as high or low temperatures can increase permanent deformation;

The so-called extrusion type sealing refers to a sealing method that relies on the rebound force generated by the sealing material after being compressed to obtain the sealing ability. Because lip seals may have a certain amount of eccentricity, it is necessary to rely on the elasticity of the material to compensate for insufficient contact stress and other issues in the seal. Therefore, the elasticity of the material is crucial for the sealing effect;

Hardness is an important indicator of sealing materials, mainly determined by the roughness of the sealing surface. When the sealing surface is relatively rough, the hardness of the sealing element should be low to ensure good sealing effect. For areas with high sealing pressure, it is required to increase the hardness of the sealing element appropriately to prevent excessive deformation of the sealing element and prevent the phenomenon of the sealing element being squeezed out. In addition, the hardness of the material decreases with increasing usage temperature, and the hardness is high, resulting in strong wear resistance of the material.

The working temperature of the sealing element depends on the temperature of the sealing medium and the temperature rise of the sealing element during its movement. Temperature directly affects sealing performance. Excessive temperature often accelerates the aging of sealing materials, reduces their elasticity, hardness, and other properties, and leads to material hardening; Low temperature can also lead to accelerated hardening of the material, loss of elastic properties, and reduced sealing effect of the material. In summary, materials with a certain temperature range should be used.

Because the degree of swelling of the material in the medium is a key factor in the sealing performance, the first factor to consider when selecting hydraulic seal materials is whether the selected material is well compatible with the sealing medium; If the sealing material is compatible with the sealing fluid, it can cause the sealing element to expand or contract, leading to failure in the early stages of use. The expansion of the seal causes an increase in frictional resistance and also causes the seal to roll. Shrinkage of the sealing element will cause a decrease in preload, a decrease in eccentricity compensation capacity, and even leakage.