DESCRIPTION: PARKER 8400 SERIES U-RINGS with built-in flexibility permit snap-in assembly and increased piston or rod clearance, thus providing reduced assembly time and lower cost. The 8400 U-Ring provides an extremely smooth, steady movement with less break-away force required because of their inherent low friction. These characteristics makes the 8400 U-Ring an excellent seal for low speed, low pressure situations. The 8400 Series U-Ring may be used in any groove design that has “U” type packings of the same cross sectional dimensions. Thus, many existing cylinders as well as new designs can utilize the benefits and advantages of the Parker 8400 Series U-Ring. The compact configuration of the Parker Packing 8400 Series U-Ring provides effective sealing and allow a designer to reduce the total weight of the unit.
The 8400 Series U-Ring is normally supplied in standard Parker Compound 4180, an 80 (A) durometer nitrile material. Compound 4180 performs effectively in a vast majority of applications. Other compounds like nitroxiles, fluorocarbons, ethylene propylene, etc., are available to fulfill specialized requirements. They may however, require special tooling, and in most cases have greater tolerances than those indicated for the standard compound. If your application requires specialized elastomers, consult a Parker Technical Representative. While the 8400 Series U-Packing seals are primarily designed for low and medium pressure applications, the pressure range may be extended by the utilization of supporting backup rings. These backup rings are required where clearances are larger than normal or where pressure exceeds 800 psi.