A piston ring includes a first ring portion which is fitted onto an outer circumferential portion of a piston and which is capable of sliding relative to an inner wall surface of a cylinder, and a second ring portion which is fitted onto the outer circumferential portion of the piston, arranged side-by-side with the first ring portion in the axial direction, and which is capable of sliding relative to the inner wall surface of the cylinder. The second ring portion is fitted onto the outer circumferential portion of the piston in such a way as to be positioned on a side opposite to a compression chamber inside the cylinder, relative to the first ring portion, and has a greater hardness than the first ring portion has.

A piston ring includes a first ring portion which is fitted onto an outer circumferential portion of a piston and which is capable of sliding relative to an inner wall surface of a cylinder, and a second ring portion which is fitted onto the outer circumferential portion of the piston, arranged side-by-side with the first ring portion in the axial direction, and which is capable of sliding relative to the inner wall surface of the cylinder. The second ring portion is fitted onto the outer circumferential portion of the piston in such a way as to be positioned on a side opposite to a compression chamber inside the cylinder, relative to the first ring portion, and has a greater hardness than the first ring portion has.

Systems and assemblies are provided for sealing an interface between a cylinder and a manifold corresponding to the cylinder. The cylinder comprises at least one port. A manifold interface is arranged adjacent to the at least one port. A seal is located inside of a circumferential pocket, wherein the circumferential pocket comprises at least a portion of the manifold interface. A spring is configured to preload the seal radially inward so that the seal stays in contact with the outer surface of the cylinder.

A piston ring set of a cryogenic pump includes a first piston ring and a second piston ring which are dissimilarly shaped and cooperatively shaped to form a hollow cylindrical shape when in abutment to one another. The first piston ring is C-shaped and defines a middle portion disposed between a first end portion and a second end portion. A piston ring gap is disposed between a first distal end of the first end portion and a second distal end of the second end portion. When the first piston ring is in abutment with the second piston ring forming the hollow cylindrical shape, the second piston ring does not extend along the middle portion of the first piston ring while the second piston ring does extend along the first end portion and second end portion of the first piston ring.

A piston ring set of a cryogenic pump includes a first piston ring and a second piston ring which are dissimilarly shaped and cooperatively shaped to form a hollow cylindrical shape when in abutment to one another. The first piston ring is C-shaped and defines a middle portion disposed between a first end portion and a second end portion. A piston ring gap is disposed between a first distal end of the first end portion and a second distal end of the second end portion. When the first piston ring is in abutment with the second piston ring forming the hollow cylindrical shape, the second piston ring does not extend along the middle portion of the first piston ring while the second piston ring does extend along the first end portion and second end portion of the first piston ring.

A seal assembly includes a tensionable annular member and a gap seal annular member that are axially juxtaposed and configured to be carried by one of a pair of coaxially movable components for sealingly engaging another one of the pair of components. The tensionable annular member includes first and second radial surfaces, an inner surface, and an outer contact surface. Rounded bottom grooves are formed across the first radial surface from the outer contact surface to the inner surface. In another embodiment, notches are formed across the inner surface from the first radial surface to the second radial surface.

A piston ring has a ring body and a ring joint. The ring body has a first and a second ring body end which lie opposite each other and which define the ring joint. The first ring body end has a protruding section with a protrusion contour cross-section, and the second ring body end has a base section with a base section contour. A protruding section separating surface of the protruding section and a base section separating surface of the base section lie opposite each other so as to sealingly contact each other in a two-dimensional manner and define a separating plane. The separating plane has an inclination opposite that of a first axial ring surface. The separating plane defines an outer separating line and an inner separating line. At least one of the separating lines has a curvature radius which is concentric to the ring body.

A piston ring has a ring body and a ring joint. The ring body has a first and a second ring body end which lie opposite each other and which define the ring joint. The first ring body end has a protruding section with a protrusion contour cross-section, and the second ring body end has a base section with a base section contour. A protruding section separating surface of the protruding section and a base section separating surface of the base section lie opposite each other so as to sealingly contact each other in a two-dimensional manner and define a separating plane. The separating plane has an inclination opposite that of a first axial ring surface. The separating plane defines an outer separating line and an inner separating line. At least one of the separating lines has a curvature radius which is concentric to the ring body.

The present disclosure provides a sealing ring assembly having a sealing ring and a reinforcement, configured to seal a high-pressure region from a lower pressure region of a piston and cylinder device. The sealing ring may be segmented, and a metal layer, wire, or other reinforcement may be affixed to the ring. The reinforcement is placed into tension against the sealing ring, which is correspondingly placed into compression. The composite structure of a relatively brittle sealing ring and reinforcement provides for reduced tensile loads in the sealing ring, thus extending life and reducing the likelihood of failure. The brittle portion of the sealing ring assembly may include a polymer or ceramic such as graphite, which is relatively less strong in tension than compression.

The present disclosure provides a sealing ring assembly having a sealing ring and a reinforcement, configured to seal a high-pressure region from a lower pressure region of a piston and cylinder device. The sealing ring may be segmented, and a metal layer, wire, or other reinforcement may be affixed to the ring. The reinforcement is placed into tension against the sealing ring, which is correspondingly placed into compression. The composite structure of a relatively brittle sealing ring and reinforcement provides for reduced tensile loads in the sealing ring, thus extending life and reducing the likelihood of failure. The brittle portion of the sealing ring assembly may include a polymer or ceramic such as graphite, which is relatively less strong in tension than compression.