A closure for a fluid end having a middle sealing section which engages a seal. The sealing section either has a larger outer diameter than adjacent sections or contacts a bore with a smaller inner diameter than adjacent sections. In either case, the clearance formed on either side of the sealing section reduces friction and allows the closure to be rocked back and forth to insert and remove the closure from the fluid end bore.

A lubricant pumping system includes a lubricant pump having a lubricant pumping space, a first seal configured to seal the lubricant pumping space, at least one signal detector, and a leakage detector for detecting leakage of a lubricant from the pumping space through the first seal and sending a signal to the signal detector in response to a detection of the leakage of the lubricant. The signal detector may produce a visual or acoustic output in response to receipt of the signal.

A fluid end having its fluid flow bores sealed without threading a retaining nut into the walls of each bore. The fluid ends may be assembled using a plurality of different kits, each kit comprising a fluid end body, a component, a retainer element, and a fastening system. The retainer element holds the component within each of the bores formed in the fluid end body and the fastening system secures the retainer element to the body. The fastening system comprises a plurality of externally threaded studs, washers and nuts in some embodiments. In other embodiments, the fastening system comprises a plurality of screws.

The disclosure concerns a seal, in particular a rod seal for sealing an axially movable rod in a guide cylinder, in particular a piston seal for a pneumatically, electrically or hydraulically driven coating agent pump for pumping coating agent, having an annular sealing element for sealingly resting on a circumferential surface of an axially movable rod, and having at least one elastic annular pretensioning element, the annular pretensioning element surrounding the annular sealing element radially on the outside and pretensioning it radially to the inside. The disclosure provides an annular seal base body which externally surrounds and holds the sealing element and the pretensioning element. In addition, the disclosure also comprises an inverted variant in which the seal is arranged in an annular groove in a lateral surface of a piston and lies sealingly against the cylinder running surface.

A sealing ring includes a first sealing element having a first mating surface and a second sealing element having a second mating surface. A high-pressure boundary extends across at least a portion of the first sealing element and across at least a portion of the second sealing element, and a low-pressure boundary extends across at least a portion of the first sealing element and across at least a portion of the second sealing element. The first mating surface, the second mating surface, or both, includes a recess open to the low-pressure boundary and not open to the high-pressure boundary. The recess may include a groove, for example. The first mating surface is sealed against the second mating surface by a first force acting on the first sealing element and a second force acting on the second sealing element. These forces act to pressure-lock the assembly.

A sealing ring includes a first sealing element having a first mating surface and a second sealing element having a second mating surface. A high-pressure boundary extends across at least a portion of the first sealing element and across at least a portion of the second sealing element, and a low-pressure boundary extends across at least a portion of the first sealing element and across at least a portion of the second sealing element. The first mating surface, the second mating surface, or both, includes a recess open to the low-pressure boundary and not open to the high-pressure boundary. The recess may include a groove, for example. The first mating surface is sealed against the second mating surface by a first force acting on the first sealing element and a second force acting on the second sealing element. These forces act to pressure-lock the assembly.

A hydraulic machine has a first assembly and a second assembly movable in rotation relative to each other along an axis of rotation. The hydraulic machine has a crankcase defining an internal volume, in which an interface between the fixed assembly and the movable assembly has a housing provided with a first sealing element ensuring the sealing of the internal volume relative to the external environment. A second sealing element is positioned between the internal volume and the housing. The second sealing element is adapted to allow a passage of fluid from the internal volume to the housing when the pressure deviation between the internal volume and the housing is less than or equal to a threshold value, and to isolate the housing from the internal volume when the pressure deviation is greater than the threshold value.

A hydraulic machine has a first assembly and a second assembly movable in rotation relative to each other along an axis of rotation. The hydraulic machine has a crankcase defining an internal volume, in which an interface between the fixed assembly and the movable assembly has a housing provided with a first sealing element ensuring the sealing of the internal volume relative to the external environment. A second sealing element is positioned between the internal volume and the housing. The second sealing element is adapted to allow a passage of fluid from the internal volume to the housing when the pressure deviation between the internal volume and the housing is less than or equal to a threshold value, and to isolate the housing from the internal volume when the pressure deviation is greater than the threshold value.

A sealing arrangement (40) is provided for sealing an interface between a casing main body (12) and a casing end cover (16). A circumferential lip (42) on the casing main body (12) defines a first radially facing circumferential surface (46) and the end cover (16) has a circumferential lip (50) defining a second radially facing circumferential surface (52). The sealing arrangement (40) includes a first circumferentially extending groove (55) formed in one of the first and second circumferential surfaces (46,52) and a sealing member (56) disposed within the first groove (55) in sealing contact with the one of said first groove (55) and in sealing contact with the other one of the first and second circumferentially extending surfaces (46,52).

A sealing assembly for a fluid end of a reciprocating pump is installable within a segment of a casing of the fluid end and is arranged to form a seal with the segment. The sealing assembly includes a closure element and a seal element. The closure element has a sealing portion with a lateral surface that faces an interior wall of the segment of the fluid end and that includes a single groove. The seal element is sized to be installed in the single groove and includes a repositionable seal. The repositionable seal is movable axially within the single groove so that the repositionable seal can be positioned in multiple sealing positions.