While there are many, complicated parts to any sort of hydraulic machine, one that usually gets ignored is the seal. Of course, there are more than one in the majority of machines, and in a wide range of sizes, but each one is just as important and necessary as the last. They do wear down with time however, so make sure you replace them as needed. If you are not sure of the exact ones you need and are searching for hydraulic cylinder seals by size, then here a few pointers to keep in mind:
The amount of different materials available for your seals might be quite staggering to the uninitiated. The seal could be made of polytetrafluoroethylene or PTFE, glass-filled PTFE, bronze-filled PTFE, nickel-filled PTFE, nitrile, silicone, polyurethane, ethylene propylene diene monomer or EPDM, fluorocarbon rubber, and others still. Obviously, knowing the material you need for your seal is only part of the necessary knowledge.
Static seals, piston seals, rod seals, symmetrical seals, and rotary shaft seals are just some of the types of seals available, not to mention there are single or double acting ones. Double acting for a seal that moves both directions in a reciprocating motion, and obviously single acting are for one direction. Plus, there are o-rings, back-up rings, buffer rings, cast iron piston rings, V-rings, gaskets and yet more still. If all of this is sounding too complicated, do not hesitate to contact a professional for some guidance.
What Do Seals Do?
Perhaps the most common aspect of a seal of which people are unaware is what exactly a seal does. The most obvious function that would come to mind is to seal something and prevent some form of liquid from leaking, but while this is certainly the primary ability of any seal, more often than not they can perform something else. Without them, high-pressure dynamic applications simply would not operate. They are more important than most even know.