When it comes to selecting the most appropriate material for the sealing element in hydraulic cylinders, there are several conditions that are important to consider. These include temperature, system pressure, media, surface roughness, system tolerances and sliding speed.
Working temperature is one of the most important aspects regarding the choice of the hydraulic seal’s material. Ideally, the working temperature would be around 50ºC for sealing elements and systems; however, application temperatures often reach 100ºC. If applications require especially high temperatures, seals made from fluoroelastomers or polytetrafluoroethylene are recommended. Speed also increases friction force and decreases oil film thickness. For that reason, polytetrafluoroethylene is again recommended for applications that require high speeds.
System pressure is another huge determining factor when it comes to the material selection for these seals. It is recommended that shock pressures be taken into consideration when calculating system pressure as these are usually higher than normal working pressures. Calculating the system pressure will guide you in selecting a sealing element with a corresponding working pressure. The media the sealing elements are being used in should also be taken into consideration. The viscosity of the media can have negative effects, such as wearing, on sealing elements, so it is important to be aware of these relationships and interactions when pairing media and sealing elements.