Too high pressure values combined with excessive fitting clearance values between rod/head and liner/piston are the main cause of seals deterioration due to extrusion in the medium run. Resulting in fluid leakages. Besides the typical operating pressure generated by the hydraulic system, other pressures may occur in cylinders: variable, unexpected and extremely high.
This happens when a machine supplied with hydraulic cylinders experiences anomalies and heavy-load events due to external factors. The resulting pressure peaks adversely affect the entire system, exposing the seals to heavy shock loads, that may cause tears or cracks and damage the whole hydraulic system.
Another condition negatively affecting the entire system is the lack of pressure or a pressure close to zero. Also in the case, it is very complicated to ensure a flawless sealing, that will be basically left to the modulus of elasticity of the seal material and to its profile, conceived to ensure an effective initial mounting preload for the seal even in lack of pressure, where no pressure support is available to keep the seal lips against the contact surface. There is minimum starting pressure request for the sealing element. It is better to choose seals with low friction property and small starting resistance.
Post time: Aug-08-2019