.png)
Hydraulic systems rely on a combination of specialized seals to function efficiently. The primary roles of hydraulic seals include retaining hydraulic fluid, preventing contamination from solids or liquids, maintaining alignment between rods and pistons, and preserving hydraulic pressure. In demanding conditions, these seals must also withstand high pressures, extreme temperatures, and transverse forces within the cylinder. Therefore, the role of hydraulic seals extends far beyond simply preventing fluid leakage.
Hydraulic piston seals prevent fluid from passing across the cylinder head, while rod seals stop fluid from leaking out of the cylinder. This controlled sealing allows pressure to build up on either side of the piston, causing the hydraulic cylinder to extend or retract accordingly. Wear rings, also known as sliding bearings, support side loads, prevent metal-to-metal contact, and ensure the concentric alignment of moving parts. Wipers or scrapers are positioned externally to block dirt, moisture, and other contaminants from entering the hydraulic system, thus maintaining a cleaner and more reliable operation.
Additionally, hydraulic cylinders require static sealing elements, such as O-rings and back-up rings, to ensure leak-free connections at rest.
Below is a schematic illustration of a hydraulic cylinder equipped with various sealing profiles offered by P & H Seals.
Let me know if you'd like to add technical labels or include image descriptions with the schematic.
Types of seals used in hydraulic cylinders
