Exploring installation of -318 plastic lined seals in one-piece seal grooves


We are continuing to explore the installability of Plastic Lined Kalsi Seals made with the stiff and highly extrusion resistant -318 seal material combination. Our literature currently reports, “We were unable to install 10.49″ extra wide plastic lined seals made with the -318 material combination into a one-piece groove without seal damage.” That statement is based on installation testing with 10.49” PN 682-20-318 seals, which have a 0.450” radial cross-section and use a 0.419” radial gland depth. During that testing, we found that PN 682-20-318 seals require a removable groove wall to ensure damage free seal installation.

We have now performed installation testing with PN 682-21-318 seals, which have a 0.415” radial cross-section and use a 0.389” radial gland depth. We found that these seals install easily into a one-piece seal groove without sustaining damage. The only difference between PN 682-20-318 seals and PN 682-21-318 seals is 0.035” of radial cross-sectional depth. Because of the smaller cross-sectional depth of the PN 682-21-318 seals, they experience less deformation during installation.

We are manufacturing an 8.434” ID BDRP seal with a 0.335” radial cross-section and will attempt to install it in a one-piece seal groove. We expect it will install, because it has about the same cross-section to diameter aspect ratio as a PN 682-21-318 seal.

The feasibility of using plastic lined rotary seals with one-piece grooves depends on factors such as diameter, radial cross-section, axial seal body width, axial lip width, and liner material. Many smaller sizes of plastic lined rotary seals made with the -318 seal material combination will still require a seal groove having a removable groove wall to ease installation and minimize the risk of seal damage. Nevertheless, it appears that Extra Wide seals made with the -318 material combination that have a cross-section to inside diameter aspect ratio of 0.410/10.490 or less can be installed in a one piece seal groove. This suggests that -318 plastic lined rotary seals with a 0.270 radial cross-section and a diameter as small as seven inches may be installable without a removable groove wall.

This is the fixture used to evaluate installation of PN 682-21-318 Kalsi-brand rotary shaft seals into a one-piece seal groove.