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Description Parker’s PolyPak seal is a patented precision molded multi-purpose seal. The Parker PolyPak combines an O-ring type synthetic rubber o-spring with a conventional lip-type seal to produce a unique sealing device capable of sealing both vacuum, high and low pressure. Conventional lip seals, such as the standard u-cups are prone to leakage under low pressure because little or no lip loading is inherent in the basic seal design.
The Parker PolyPak however, is a squeeze type seal and provides high sealability at low pressure. As system pressure increases, additional force is applied to the PolyPak’s seal interface and as pressure continues to increase, lip loading is automatically increased to compensate for this higher pressure and thus maintain a positive, leak-free seal from hard vacuum to over 60,000 psi with proper design and auxiliary devices. In addition to providing superior sealing in vacuum, low and high pressure applications, the PolyPak seal offers a number of distinct advantages over conventional symmetrical or non-symmetrical u-cup seals including: • The PolyPak’s o-spring stabilizes the seal under extreme pressures, preventing seal lip distortion and rolling or twisting in the gland. • At low or high temperature extremes, the o-spring maintains lip loading on both I.D. Of the seal interface. Sramakrishnan books pdf free. • The PolyPak seal can be stretched or squeezed to accommodate oversize cylinder bores and undersize rods.
As long as the seal cross-section is correct in relation to the radial groove dimensions, the PolyPak will compensate and maintain proper lip loading. • The range of materials available to the user of the PolyPak seal insures the proper combination for abrasion, extrusion, temperature resistance and fluid compatability which produces high sealability and long life.