Abstract: An apparatus for measuring tension of piston rings includes a cylindrical support fixture having a circumferential groove formed therearound for receiving and holding a piston ring. A rigid base supports a plurality of components of the apparatus. A strong, thin band, formed from a material sufficiently strong to withstand repeated applications of pulling force thereto, is mounted to the base, and is held between two clamps. The band has a loop formed therein, for receiving the support fixture with a piston ring mounted therein. The apparatus also includes reciprocally movable structure for tightening the band around the support fixture, such as a slidably movable clamp assembly at one end of the band. The apparatus further includes mechanism for measuring tension on the band, and fluid activatable mechanism for vertically reciprocating a portion of the support fixture. In a preferred embodiment, the reciprocating mechanism is pneumatically activatable, such as by compressed air.

Abstract: A filter medium for filtration of a fluid to flow therethrough from an upstream side to a downstream side thereof, said filter medium comprising a substrate having a density gradient wherein the density is high on the upstream side and low on the downstream side of the substrate.