An annular scraper ring assembly for a packing arrangement is disclosed. The annular scraper ring assembly can form a seal with a plunger included in a fluid end of a reciprocating pump and includes two or more rings, including a first ring and a second ring. The first ring is formed from a resilient material configured to form a seal against a plunger included in a fluid end of a reciprocating pump and includes an upstream face and an inner surface. The second ring defines a caroming surface configured to engage the upstream face of the first ring and cam the inner surface inwards when the first ring is compressed against the second ring.

An annular scraper ring assembly for a packing arrangement is disclosed. The annular scraper ring assembly can form a seal with a plunger included in a fluid end of a reciprocating pump and includes two or more rings, including a first ring and a second ring. The first ring is formed from a resilient material configured to form a seal against a plunger included in a fluid end of a reciprocating pump and includes an upstream face and an inner surface. The second ring defines a caroming surface configured to engage the upstream face of the first ring and cam the inner surface inwards when the first ring is compressed against the second ring.

An annular scraper ring for a packing arrangement is disclosed. The annular scraper ring that can form a seal with a plunger included in a fluid end of a reciprocating pump and includes a planar upstream face and an inner surface with a tapered section. The tapered section tapers away from the plunger along a downstream direction so that the scraper ring is widest at the planar upstream face.

An annular scraper ring for a packing arrangement is disclosed. The annular scraper ring that can form a seal with a plunger included in a fluid end of a reciprocating pump and includes a planar upstream face and an inner surface with a tapered section. The tapered section tapers away from the plunger along a downstream direction so that the scraper ring is widest at the planar upstream face.

A multi-piece oil scraper piston ring includes a slotted spring element and at least one lamella element which is operatively connected to the slotted spring element and provided with a joint, the spring element being designed as a meander spring that axially receives and radially supports the lamella element, the two end regions of the meander spring being provided with legs that extend approximately parallel to one another and the axial length of which is designed such that the legs at least partially engage in the joint of the lamella element.

A multi-piece oil scraper piston ring includes a slotted spring element and at least one lamella element which is operatively connected to the slotted spring element and provided with a joint, the spring element being designed as a meander spring that axially receives and radially supports the lamella element, the two end regions of the meander spring being provided with legs that extend approximately parallel to one another and the axial length of which is designed such that the legs at least partially engage in the joint of the lamella element.

Embodiments of a combination piston and piston ring to reduce the volume of a crevice defined between the circumferential wall of a cylinder and a portion of the outer wall of a piston within the cylinder, the portion extending down from the top of the piston. The combination piston and piston ring is configured such that pressurized fluid within the cylinder reliably urges a radial face of the piston ring to sealingly engage the circumferential wall of the cylinder, even as the piston reciprocates within the cylinder.

Embodiments of a combination piston and piston ring to reduce the volume of a crevice defined between the circumferential wall of a cylinder and a portion of the outer wall of a piston within the cylinder, the portion extending down from the top of the piston. The combination piston and piston ring is configured such that pressurized fluid within the cylinder reliably urges a radial face of the piston ring to sealingly engage the circumferential wall of the cylinder, even as the piston reciprocates within the cylinder.

An unchamfered piston ring that is pre-treated by grit blasting to a defined roughness, followed by PVD coating with a metal nitride to a thickness of at least 10 μm, leaving peaks and valleys in the coated piston ring. The coated piston ring is then lapped to remove the peaks without penetrating the coating, so that valleys and plateaus remain in the coated surface. The resulting piston ring exhibits superior coating retention due to the increased surface area created by the grit blasting, and yet also superior performance, as the cavities remaining increase the porosity of the coating and thus enhance the lubrication of the ring.

The object of this invention is to increase the life of the displacer and stem seals of the reciprocating displacer of a Gifford McMahon (GM) cryogenic expander. The seal comprises a ring that is relatively long and thin and uses the pressure difference across the seal, acting behind the ring, as the primary force to bring the ring into contact with the cylinder and stem walls. The pressure difference across the seal ring pushes the ring to one end of the groove, and the friction force pushes the ring in the same direction while it is moving. The sealing force is distributed over a larger area compared with a conventional backed “O” ring thus reducing the wear rate and increasing the seal life.