A method for carrying out emergent shaft sealing for a reactor coolant pump and a shaft sealing assembly is provided. The method comprises the steps that a passive stopping sealing member is arranged in a first sealing assembly and forms an opening under the normal operation condition, without affecting the first sealing assembly using a liquid film formed by fluid static pressure to prevent reactor coolant from leaking along a pump shaft; under the station blackout condition, after sensing high-temperature fluid flowing into the first sealing assembly, the passive stopping sealing member is closed and holds the pump shaft of the reactor coolant pump tightly, the gap between the first sealing assembly and the pump shaft of the reactor coolant pump is blocked, and therefore the reactor coolant is prevented from leaking along the pump shaft.

The present disclosure provides radial springs that control radial forces between adjacent concentric components. The radial springs may be configured for placement between the adjacent concentric components. The radial springs may include a base member, support members extending from the base member, and resilient members extending from the base members. The resilient members may extend radially, axially, at an angle relative to the axis, or a combination thereof, and may be radially deformable. The resilient members may exert radial forces substantially uniformly radially inward or outward in use. The resilient members may be leaf type members or cantilever type members. The support members and resilient members may be provided on a radially inward or outward side of the base member. The methods of installing and uninstalling radial springs may include engaging the resilient members with a tool and radially deforming the resilient members to engage or disengage the radial spring from an adjacent concentric component.

A wobble piston is provided to be used in an air compressor for providing compressed air, and includes a piston cap having a generally flat first plate and a peripheral edge extending downwardly from the first plate. A connecting support rod is connected to the piston cap, and a compression ring is clamped between the edge of the piston cap and the support rod in complementary fashion. Upon assembly between the cap and the support rod, the compression ring has an angled side wall that is bent upwardly inwardly at a predetermined obtuse angle relative to a longitudinal axis of a cylinder.

A combination oil ring includes a pair of upper and lower side rails and a spacer expander arranged therebetween, the spacer expander including a plurality of upper pieces and lower pieces alternately arranged in a circumferential direction with the pieces axially and circumferentially apart from each other, a coupling piece coupling pieces adjacent to each other, and flange portions formed standing at inner circumferential-side end portions of the upper pieces and the lower pieces so as to press the side rails, and a through hole being formed in the flange portions, wherein side rail support portions that project axially are formed at portions in the circumferential direction of outer circumferential-side end portions of the upper pieces and the lower pieces.

A piston ring for at least one of a piston of an internal combustion engine and a compressor may include at least one substantially annular metallic base having a nitrided layer. The base may include at least one chamfer and at least one outer surface that maintains contact with a layer of lubricating oil. The nitrided layer may exhibit a substantially constant thickness over at least one surface of the base and the at least one chamfer. The nitrided layer may include a nitrided diffusion layer that maintains direct contact with the layer of lubricating oil and has a residual tension ranging from +100 megapascal to 100 megapascal.

A piston ring for at least one of a piston of an internal combustion engine and a compressor may include at least one substantially annular metallic base having a nitrided layer. The base may include at least one chamfer and at least one outer surface that maintains contact with a layer of lubricating oil. The nitrided layer may exhibit a substantially constant thickness over at least one surface of the base and the at least one chamfer. The nitrided layer may include a nitrided diffusion layer that maintains direct contact with the layer of lubricating oil and has a residual tension ranging from +100 megapascal to 100 megapascal.

A coupling unit is disclosed which includes a sleeve opening that extends in the longitudinal direction and into which at least one medium-conveying plug element can be at least partially inserted, A support sleeve includes at least one circumferential pocket on an inner side that faces a plug element and defines the sleeve opening transverse to the longitudinal direction. A sliding element is arranged in the pocket and movably transferred from a release position into a coupling position during the insertion of the plug element. A sealing element is arranged between the sliding element and the pocket of the support sleeve in the release position and pre-stressed in the direction of the plug element. The sealing element is released by the sliding element in the coupling position in order to close and seal a potential gap formed between the support sleeve and the plug element.

A coupling unit is disclosed which includes a sleeve opening that extends in the longitudinal direction and into which at least one medium-conveying plug element can be at least partially inserted, A support sleeve includes at least one circumferential pocket on an inner side that faces a plug element and defines the sleeve opening transverse to the longitudinal direction. A sliding element is arranged in the pocket and movably transferred from a release position into a coupling position during the insertion of the plug element. A sealing element is arranged between the sliding element and the pocket of the support sleeve in the release position and pre-stressed in the direction of the plug element. The sealing element is released by the sliding element in the coupling position in order to close and seal a potential gap formed between the support sleeve and the plug element.

A piston assembly for a nailer is provided, and includes a piston body with an upper surface, a lower surface and a peripheral edge. A peripheral gland is located between the upper and lower surfaces, the gland having an inner closed end and defining an annular space. An annular piston seal is disposed in the gland, and a plurality of spaced air ports are disposed adjacent the peripheral edge, the ports each being in fluid communication with the gland. The gland and the seal are dimensioned so that during a power cycle of the nailer, pressurized air generated during a fastener driving stroke enters the ports and radially expands the seal for enhancing friction between the seal and a surrounding cylinder. During a return stroke, the seal is radially retracted within the gland to reduce friction between the seal and the cylinder.

A combined oil control ring comprising a pair of circular side rails each having a gap, and a waved spacer expander longitudinally sandwiched by the side rails, which has seating tabs for pushing inner surfaces of the side rails on the inner side, (a) the radial thickness a.sub.1 of the side rail being 50-90% of the height a.sub.9 of the spacer expander, or (b) the height a.sub.10 of the seating tab being 23-60% of the height a.sub.9 of the spacer expander.