For a high pressure resistant hose, especially a hydraulic hose, the sealing is very important. If the hose has bad sealing performance, it will cause leakage. Then it will affect the whole hydraulic system. Then what factors cause a bad sealing performance of high pressure resistant hose joint?
First, the medium movement speed can affect the sealing performance
When the movement speed is high (>0.8m/s), the lubricant film in the high pressure hose may be destroyed. Due to the lack of good lubrication, it will heat the oil seal. Then it will greatly reduce the service life. While when the speed is very low (<0.03m/s), you should consider the stability of the hose assembly.
Orientflex suggests that the working range of PU or rubber and plastic oil seals is 0.03m/s ~ 0.8m/s.
Working temperature can also affect the high pressure resistant hose
High temp will cause the volume of the oil seal to expand and soften. Then it causes the friction resistance to increase rapidly and the pressure resistance to decrease. While low temp will reduce the elasticity of PU or rubber and plastic oil seals. Thus it will cause leakage, and even the entire oil seal will become hard and brittle.
The ideal continuous operating temp range of PU or rubber-plastic oil seals is -10~80℃.
Oil seal has min starting pressure
When you apply high pressure, consider the deformation of the sealing oil under pressure. Then you should use anti-crush buckles. While for low pressure operation, you should choose oil seals with low friction and low starting resistance. At a pressure of 2.5 MPa, PU oil seals are not suitable. While oil seals of different materials have different optimal working pressure ranges. The optimal working pressure range of PU oil seal is 2.5-31.5 MPa.
In a word, you should use the high pressure hose assembly with proper pressure and temp.