The role of scraper rings (wipers) is to prevent the entry of hard dirt particles into hydraulic and pneumatic systems, such as cylinders or valves. This avoids energy losses in the pressure medium, damage to seals, moving surfaces, and guiding shafts.

When working with folded bellows, which offer universal protection, it is important to keep in mind their sensitivity to damage. For this reason, their use is limited to specific situations. In most cases, the scraper ring provides sufficiently effective protection. The most practical solution is the production of a single-lip ring made from a particularly durable elastomer.

It is crucial to ensure that the scraper rings remain undamaged. The internal diameter of the installation space, for example on piston rods, must be precisely executed to ensure proper positioning and function of the ring.

Since scraper rings adhere to the piston rods under external preload, they can increase friction at the start of movement. Additionally, this preload, combined with the sharp edges of the wipers, may cause slight oil leakage along the piston rod during its operation. This leakage must be taken into account when designing and maintaining the system.