Piston Cups are available in various shapes and compounds. The
selection should be made on the basis of pressure, temperature, and the
type of air or fluid medium in which the cup must function.
The Standard K Series are homogeneous cups made to handle low
pressures (under 1000 pounds/sq. inch) in air, water, petroleum base
hydraulic fluids, and lubricating oils. The K series can be ordered in
Buna-N, EPR, Viton, Silicone, and most other homogeneous materials.
A reinforced version of the K series prevents extrusion in medium
pressure installations (up to 3000 p.s.i.) or where diametrical clearances
are greater. These cups typically are made with stiff but flexible Buna-N
and cotton duck fabric. They are also available in softer compounds for
lower pressure applications where reinforcement is desired.
A heavy duty reinforced version of the K series is designed for extremely
high pressure installations, and typically uses a combination of Buna-N,
cotton duck fabric and other hardeners.
All K series piston cups can be supplied with center holes and bolt holes.
The KMFP and KWAB style cups are special OEM designs for the