The Quad-Ring® seal is a special configuration ring packing, manufactured by the Minnesota Rubber. As opposed to an O-ring, a Quad-Ring® seal has a more square cross-sectional shape with rounded corners (fig. 7-16). The Quad-Ring® seal design offers more stability than the O-ring design and practically eliminates the spiraling or twisting that is sometimes encountered with the O-ring.
Quad-Rings® seals are completely interchangeable with O-rings in the sizes offered by the manufacturer. They may be installed with one or two backup rings, depending upon the specific seal groove application and width. The Quad-Ring® seal works well in, both hydraulic and pneumatic systems.
Many Quad-Ring® seal sizes have been assigned NSNs and are stocked in the Federal Supply System. Quad-Ring® seals in manufacturer’s sizes designated as Q1 through Q88 are interchangeable with O-rings conforming to AN6227. Likewise, Quad-Ring® seals in commercial sizes Q101 through Q152 are interchangeable with O-rings conforming to AN6230 in the respective dash sizes from –1 through–52. Therefore, the Quad-Ring® seal stock part number uses the AN standard O-ring designations AN6227 and AN6230 and the commercial Q dash number designation. For example, NSNs are found under such reference part numbers as AN6227Q10 and AN6230Q103. If the letter Q does not follow AN6227 or AN6230, the part number is an O-ring not a Quad-Ring® seal.
If Quad-Ring® seals are not available for maintenance actions, appropriate sized O-rings can be installed and they work satisfactorily.