Hydraulic & Pneumatic Seals

Hydraulic and pneumatic seals are sealing components used for applications with rotary or reciprocating motions, they are commonly found in cylinders.

Hydraulic Seals:

1. Types of Hydraulic Seals:

O-Rings: Circular seals that fit into a groove and are compressed between two parts to create a seal.
U-Cups: U-shaped seals that are loaded in the axial or radial direction.
Wipers/Scraper Seals: Designed to prevent contaminants from entering the hydraulic system.
Rod Seals: Installed on the rod to prevent fluid from leaking out of the cylinder.

2. Material:

Common materials include rubber compounds, polyurethane, and other synthetic materials.
The choice of material depends on factors such as temperature, pressure, and the type of fluid used.

3. Functions:

Seal fluid between components in a hydraulic system.
Prevent contamination from entering the system.

Pneumatic Seals:

1. Types of Pneumatic Seals:

Piston Seals: Seal the gap between the piston and cylinder bore.
Rod Seals: Seal the gap between the rod and the gland.
Wipers/Scraper Seals: Prevent external contaminants from entering the pneumatic system.
O-Rings: Also used in pneumatic applications.

2. Material:

Materials like nitrile rubber, polyurethane, and other polymers are commonly used for pneumatic seals.
Pneumatic seals are generally lighter and may have different material requirements compared to hydraulic seals.

3. Functions:

Seal air or gas between components in a pneumatic system.
Prevent external contaminants from entering the system.

Key Differences:

1. Pressure Levels:

Hydraulic systems generally operate at higher pressures than pneumatic systems.

2. Size and Weight:

Pneumatic seals are often lighter and smaller than hydraulic seals due to the lower pressures in pneumatic systems.

3. Material Compatibility:

Hydraulic seals need to withstand a wider range of fluids, including oils, whereas pneumatic seals primarily deal with compressed air or gases.

4. Application Specifics:

While there is some overlap, seals are often designed with specific application requirements in mind, whether hydraulic or pneumatic.