A sealing assembly for a shaft includes: a first sealing component; a first spring energizer associated with said first sealing component; an annular support member configured for supporting said first sealing component; a second sealing component; a second spring energizer associated with said second sealing component, said first and second sealing components each having a pair of seal lips, said pairs of seal lips facing each other, said first and second spring energizers each configured for energizing respectively said first and second sealing components, each said spring energizer being respectively between one said pair of seal lips, said annular support member being disposed about the shaft and positioned between said first and second sealing components and said first and second spring energizers, said annular support member including two outwardly facing protuberances each of which interfits with a respective said pair of seal lips.

[Problem] To provide a sealing device having high pressure resistance and durability for a reciprocating shaft. [Solution] A sealing device comprising an oil seal member and a dust seal member. The oil seal member and the dust seal member each comprise a rigid ring provided inside a shaft hole and an elastic ring attached to the rigid ring, wherein the elastic ring has formed thereon a lip that slidably contacts a reciprocating shaft. The rigid ring of the dust seal member is detachably fitted in the rigid ring of the oil seal member. The sealing device further comprises another rigid ring provided between the elastic ring of the oil seal member and the elastic ring of the dust seal member in a direction parallel to the axial direction of the reciprocating shaft. This rigid ring is detachably fitted in a concave portion formed radially inward of the rigid ring of the dust seal member and reinforces the elastic ring of the dust seal member.

A sealing structure suppresses possible damage to a seal ring because of a backup ring. The sealing structure is characterized in that a cut portion 150 that is cut in a planar shape is formed in a backup ring 100 at one position in a circumferential direction, the cut portion 150 is configured such that a cut surface 153 is oblique to a central axis of the backup ring 100, an acute angle of angles between a surface on the high pressure side of the backup ring 100 and the cut surface 153 is set to not less than 15° and not more than 30°, and the backup ring 100 is formed of a resin material having Rockwell hardness of 100 or less, durometer hardness of 70 or less, and elastic modulus of 1.0 GPa or less.

[Problem] To provide a sealing device having high pressure-resistance and durability for a reciprocating shaft. [Solution] A sealing device comprising an oil seal member and a dust seal member. The oil seal member and the dust seal member each comprise a rigid ring provided inside a shaft hole and an elastic ring attached to the rigid ring, wherein the elastic ring has formed thereon a lip for slidably contacting a reciprocating shaft. The sealing device further comprises an intermediate rigid ring provided between the elastic ring of the oil seal member and the elastic ring of the dust seal member, in a direction parallel to the axial direction of the reciprocating shaft.

A variable back-up ring includes: a first half shell; a second half shell having a symmetrical shape to the first half shell; and an inner cavity defined by the first half shell and the second half shell. The first half shell and the second half shell are deformable depending on a magnitude of a fluid pressure acting on the first half shell and the second half shell.

Proposed is a seal for high pressure water jets, the high pressure water jets each includes a housing, a connector through which high pressure water is introduced, a rotary body exposed in a direction in which the high pressure water inside the housing is discharged, a rotary support for supporting the rotary body, a nozzle connected to an end of the rotary body, a shaft, a bushing, and a seal coupled to the outer circumferential surface of the shaft and having a surface in close contact with the bushing, wherein the seal includes an outer seal provided with a through hole having a tapered portion inclined so that the inner diameter thereof is expanded in the direction in which the high pressure water is discharged, and an inner seal inserted in the tapered portion of the outer seal and having the same inner diameter as that of the through hole.

A valve device includes: a seal member that is slidably in close contact with an outer peripheral surface of a rotation shaft; and an annular attachment ring that attaches the seal member to a housing. The seal member has a first-side plate part and a second-side plate part sandwiching and holding the seal member in an axial direction of the rotation shaft. An inner peripheral end of the second-side plate part is positioned radially outside beyond an inner peripheral end of the first-side plate part. An outer surface of the first-side plate part includes an outer peripheral-side region positioned radially outside beyond the inner peripheral end of the second-side plate part and an inner peripheral-side region positioned radially inside beyond the outer peripheral-side region. The outer peripheral-side region is positioned on a first side of the axial direction with respect to the inner peripheral-side region.

A technique facilitates improved sealing with respect to safety valve pistons so as to improve reliable safety valve operation. According to an embodiment, a safety valve piston seal assembly is positioned about a safety valve piston and comprises components which divert a load path to the safety valve piston rather than to susceptible components of the seal assembly. For example, the seal assembly may comprise a load ring and spacers to energize a V-ring when pressure is applied to a metal spring energized (MSE) seal. However, the components are arranged so the load path is diverted to the safety valve piston when pressure occurs behind the V-ring instead of allowing the loading to act against the MSE seal.

A sealing device in which diameter expansion of an inserted first back-up ring is suppressed. The sealing device includes a seal ring mounted in a rectangular mounting groove, the first back-up ring, and a second back-up ring. The first back-up ring has an end surface contacting an opposing-sealing-fluid-side side surface of the mounting groove. The second back-up ring has an end surface contacting the seal ring. A contact surface in an inner peripheral end of second back-up ring is perpendicular to the axis to contact an opposing-sealing-fluid-side side surface of the mounting groove. The inner diameter of the first back-up ring is set to be larger than the outer diameter of the contact surface portion of the second back-up ring, and the outer diameter of the first back-up ring is set to be smaller than the inner diameter of a housing.

Provided is a composite seal member that can maintain performance such as vacuum seal performance, plasma resistance, and corrosive gas resistance over a long period. The composite seal member is mounted in a seal groove provided in a body surface of a first member, and establishes a sealed state between the first member and a second member when the second member is moved closer toward the first member. The composite seal member includes a first seal member disposed on the side of a first side wall of the seal groove and made of an elastic member, and a second seal member disposed on the side of a second side wall of the seal groove and made of a material that is harder than the first seal member. The second seal member has at least a second side wall abutment surface that extends generally in parallel with and makes surface contact with the second side wall of the seal groove, and a seal abutment surface that extends generally in parallel with a seal surface of the second member, and that makes surface contact with the seal surface of the second member in the sealed state.