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Standard Circumference Seals

Introduction of Stein Seal Standard Circumferential Seals

For over 65 years Stein Seal Company has been a leader in the custom design, testing and manufacturing of seals and precision components for demanding and critical applications in military and commercial aircraft engines, power generation equipment, pumps, compressors, centrifuges, and the military and commercial marine industry. Leveraging the knowledge and experience that has been accumulated from our custom seal products, we have also created a line of standardized circumferential seals.

Our standard circumferential seals operate using air pressure differential and spring loading to collapse a segmented carbon seal ring onto a rotating shaft or other rotating seal surface such as a runner. Generally, our circumferential seals are placed in applications to prevent leakage between an oil mist and dry air environments when high shaft speed, high temperatures, or high axial shaft movement are present.

Seal Components 

Our standard circumferential seals all comprise the same subcomponents, regardless of seal size.


Table 1 outlines the material of each subcomponent within the standard circumferential seal assembly. The materials used in the standard circumferential seals were chosen based on historical performance data and best practices developed from proven custom Stein Seal products.

Standard Sizes

The sizes of standard circumferential seals are based on their sealing diameter. A list of available sizes is provided in Table 2 along with their respective recommended installation bore diameters. All standard seals have the same axial width as defined in Figure 2.


Performance Characteristics

Figure 3 shows seal leakage performance vs the delta pressure of each standard seal size at the maximum operating temperature.


Rated to max carbon operating temperature of 600°F (315.6°C)

Rated to withstand a maximum shaft speed ranging from 20,000-30,000 RPM

Performance and limitations vary based on the operating environment.

Application-specific estimates and additional data are available upon request.

Beyond Standard Circumferential Seals 

Stein Seal® Company offers custom seal products beyond the standard sizes ranging from 1 to 30+ inches to meet custom applications. More information can be provided upon request.

Table 2: Standard Circ. Seal Sizes

Figure 2: Standard Circ. Seal Size Diagram

Figure 3: Standard Circ. Seal Leakage vs Delta Pressure at 600°F