In order to provide a sealing device (15) for sealing a piston rod (8) of a reciprocating compressor (1), which provides good sealing properties at compressor standstill, which has a simple structure, which allows for a simple handling and which requires no external source of energy, the sealing device (15) comprises a number of first packing retainers (18), each retainer including a retaining opening (18a) in which a first packing ring (19) is arranged, a second packing retainer (20), including a retaining opening (20a) in which a second packing ring (21) is arranged, the second retainer (20) being positioned closer to the second axial device end (15b) than the number of first packing retainers (18) in an axial direction of the sealing device (15), wherein the second packing ring (21) is an uncut ring, comprising a continuous inner circumferential sealing surface (21a), wherein the second packing ring (21) is made from a material comprising a polymer, the material having a thermal expansion coefficient (?), which is at least two times higher than the thermal expansion coefficient (?FE) of iron, wherein at or below a defined activation temperature an inner diameter (d_i) of the second packing ring (21) is smaller than an outer diameter (D_a) of the piston rod (8) to be sealed, such that in the mounted state of the sealing device (15) in the compressor (1) the second packing ring (21) is prestressed in a radial direction in order to form a tight seal between the continuous inner circumferential sealing surface (21a) of the second packing ring (21) and the outer circumferential surface (8a) of the piston rod (8), wherein at a given operating temperature, the inner diameter (d_i) of the second packing ring (21) is larger than the outer diameter (D_a) of the piston rod (8), such that in the mounted state of the sealing device (15) in the compressor (1) the continuous inner circumferential sealing surface (21a) of the second sealing ring (21) is detached from the outer circumferential surface (8a) of the piston rod (8) in order to provide a leakage path past the second packing ring (21) in the axial direction.

A seal structure is provided to block a clearance between a rotational casing and a fixed housing for driving a crawler of a crawler vehicle. A seal ring is held in a first annular holding groove provided in the fixed housing together with a first O-ring that biases the seal ring toward the outside of the first holding groove. A second holding groove having an opening facing the first holding groove is provided in the rotational casing to hold a slide ring having a higher rigidity than that of the seal ring together with a second O-ring that biases the slide ring toward the seal ring. A foreign object such as mud is thereby prevented from invading a gear chamber without increasing a frictional loss.

A shaft seal assembly may include a stator and a rotor. The rotor may be configured to rotate with a shaft, and the stator may be engaged with a housing. The stator and rotor may be configured with radial and/or axial recesses and/or radial and/or axial projections. These various features may be configured such that the stator and rotor cooperate to form a ring cavity. A cooperating ring may be positioned in the ring cavity, and the cooperating ring may be configured such that is circumferentially expandable so that the cooperating ring changes size and/or shape when it rotates as opposed to when it is not rotating.

The shaft sealing structure includes a seal ring that has abutment portions formed by dividing the seal ring along the axial direction and that is provided around a main shaft in a ring-like manner; a support member that is provided in the seal ring along the circumferential direction of the main shaft; and a thermoswitch that is connected to the support member between the abutment portions and that presses the support member toward the center of the main shaft when the temperature rises to a temperature higher than that during normal operation, in which the seal ring is fixed at a position separated from the main shaft during the normal operation and is moved by the support member toward the center of the main shaft when the temperature rises to a temperature higher than that during the normal operation.

A sealing element assembly (1) for a single type mechanical shaft seal assembly (2) is adapted to be arranged between the circumference of a rotatable shaft (3) and a static housing (4) surrounding the shaft (3). A first side (5) in an axial direction of the sealing element assembly (1) is adapted to face an enclosed space (6) between the housing (4) and the shaft (3) and the opposite second side (7) of the sealing element assembly (1) is adapted to face an ambient space (8), wherein the sealing element assembly (1) is adapted to be at least partly moveably arranged in an axial direction from a non-sealing position to a sealing position. The sealing element assembly (1) in the non-sealing position is adapted to be arranged at distance from a surface (10) of a plane that is transversal or tapered up to ?5 degrees to an axis of the shaft (3). The sealing position of the sealing element assembly (1) is arranged to seal against said surface (10) such that the sealing element assembly (1) constitutes a sealing between the rotatable shaft (3) and the housing (4) when the enclosed space (6) is pressurized.

A seal section for use in a downhole submersible pumping system includes one or more fluid separation mechanisms, a shaft and one or more primary mechanical seals. Each of the one or more primary mechanical seals is disposed along the shaft. The seal section also includes one or more redundant shaft seals that each substantially surrounds a corresponding one of the one or more primary mechanical seals. In another aspect, a seal section for use in a pumping system includes one or more fluid separation mechanisms, a shaft, a primary mechanical seal and a redundant shaft seal. The redundant shaft seal substantially surrounds the primary mechanical seal. The seal section further includes an internal seal chamber defined by the annular space between the primary mechanical seal and the redundant shaft seal.

A habitation module that provides an artificial gravity environment. In one embodiment, the habitation module includes a rotating structure configured to rotate about an axis in relation to a stationary structure, and attachment assemblies configured to rotatably couple the rotating structure to the stationary structure. The attachment assemblies comprise bearings installed coaxially between a cylindrical housing of the rotating structure and a cylindrical body member of the stationary structure, and dynamic radial seals installed coaxially between the cylindrical housing and the cylindrical body member. The attachment assemblies further comprise a static seal assembly that includes an end cap movable between a locked position and an unlocked position.

A seal assembly for sealing a shaft bearing includes a seal housing, first and second seal rings retained by the seal housing, an annular chamber formed between the first and second seal rings and a connecting channel configured to place the annular chamber in fluid communication with a bearing-housing-side oil space. When the seal assembly is installed on a shaft, the connecting channel is configured to permit a fill-level equalization between the oil space and the annular chamber when the oil space is filled to a first possible fill level (N.sub.1) and to prevent the fill-level equalization between oil space and annular chamber when the oil space is filled to a second possible fill level (N.sub.2).

A shaft seal assembly may include a stator and a rotor. The rotor may be configured to rotate with a shaft, and the stator may be engaged with a housing. The stator and rotor may be configured with radial and/or axial recesses and/or radial and/or axial projections. These various features may be configured such that the stator and rotor cooperate to form a ring cavity. A cooperating ring may be positioned in the ring cavity, and the cooperating ring may be configured such that is circumferentially expandable so that the cooperating ring changes size and/or shape when it rotates as opposed to when it is not rotating.

Self-sealing bellows for use with vehicles are disclosed. An example bellows includes a tubular body being expandable and contractible along an axis of the body. The bellows also includes a lining disposed along a surface of the body and a liquid or gelatinous material disposed between the body and the lining. The liquid or gelatinous material hardens when exposed to a fluid.