A piston rod seal unit. The piston rod seal unit includes a housing, a cylinder gland, and at least one floating rod seal assembly mounted in the cylinder gland, the floating rod seal assembly comprising at least one rod seal mounted onto the floating rod seal assembly.

A circumferential seal assembly suitable for forming a thin film between a rotatable runner and a sealing ring is presented. The assembly includes an annular seal housing, a rotatable runner, an annular seal ring, and a plurality of groove structures. Each groove structure includes a groove and an optional feed groove. The groove includes at least two adjoining steps defined by base walls arranged to decrease depthwise. Two adjoining base walls are disposed about a base shoulder. Each base shoulder locally redirects a longitudinal flow to form an outward radial flow in the direction of the annular seal ring. The base walls are bounded by and intersect a pair of side walls. A side wall includes side shoulders which narrows the groove widthwise and locally redirects the longitudinal flow to form a lateral flow in the direction of the other side wall. Outward and lateral flows separately or in combination enhance stiffness of a thin-film layer between the annular seal ring and the rotatable runner.

An intershaft seal assembly for use between an inner shaft and an outer shaft rotatable within a turbine engine is presented. The seal assembly includes a sealing ring, an inner ring, and a pair of end rings. The sealing ring further includes a plurality of asymmetric ring segments whereby each asymmetric ring segment further includes a vertical flange and a pair of horizontal flanges extending from the vertical flange in a non-symmetric arrangement. The non-symmetric seal geometry provides an axial force balance thereby reducing wear and increasing seal life. The sealing ring is disposed about the inner ring. The inner ring includes a plurality of ridges that engage the asymmetric ring segments so as to prevent rotation of the asymmetric ring segments with respect to the inner shaft. The end rings are disposed about the sealing ring and the inner ring. The horizontal flanges separately contact the end rings so that the vertical flange extends from and between the end rings in the direction of the outer shaft. A non-contact seal is formed between an outer sealing surface along the vertical flange and an inner sealing surface along the outer shaft.

An aspirating face seal assembly for a turbo-machine including a rotor assembly having a first radially extending portion defining a rotor surface is disclosed. The aspirating face seal assembly includes a seal body including a second radially extending portion defining a bearing surface and having a plurality of return channels. The second radially extending portion is disposed in the turbo-machine such that the bearing surface is disposed facing the rotor surface. The aspirating face seal assembly further includes an annular ring including one or more openings. The annular ring is concentrically disposed on the second radially extending portion and between the rotor surface and the second radially extending portion and configured to rotate in an event of rub between the first radially extending portion and the annular ring. A turbo-machine including the aspirating face seal assembly and a method for operating an aspirating face seal are also disclosed.

An oil-free screw compressor includes: a casing having a rotor chamber; a bearing supporting rotary shafts of the screw rotors; a shaft seal device including an oil seal portion and an air seal portion; an atmosphere open hole formed in the shaft seal device; at least one communication hole formed in the rotary shaft; and an annular space communicating the atmosphere open hole with the at least one communication hole communicate with each other. The annular space includes an inner peripheral annular space formed on an inner peripheral side of the casing. Assuming an open cross-sectional area of the inner peripheral annular space as S1, a total open cross-sectional area of the communication holes as S2, an open cross-sectional area of the i-th communication hole out of the communication holes as S2i, and the number of communication holes as n (n being a natural number of 1 or more), a following relationship is satisfied.

[00001]$S.Math..Math.1\geqq S.Math..Math.2=\underset{i=1}{\overset{n}{.Math.}}.Math..Math.S.Math..Math.2.Math.i$

Aspects of the disclosure are directed to a seal comprising: a support ring, at least one beam coupled to the support ring, and a shoe coupled to the at least one beam, the shoe having an axial shoe face that includes a rounded edge that is configured to contact a support structure face of a support structure when the seal is subjected to a load that is equal to or greater than a first threshold.

An external combustion engine including a burner element, a heater head, a piston cylinder containing a piston, a cooler and a crankcase. The crankcase includes a crankshaft, a piston rod connected to the piston, a drive mechanism for converting the linear motion of the piston rod to rotary motion of the crankshaft and a linear cross-head bearing that is connected rigidly to the piston rod at one end and to the drive mechanism at the other end. Also the external combustion engine includes a piston clearance seal and a piston rod seal unit that has floating rod seals. The piston includes a inner dome to reduce axial heat transfer via radiation and convection.

A seal assembly is disclosed for sealing a high pressure fluid cavity from a low pressure fluid cavity. The cavities are at least partially disposed between a rotatable shaft and a sump housing. The seal assembly comprises a circumferential runner and a seal ring. The circumferential runner is carried by the shaft and has a radially outward facing seal surface extending axially along the shaft. The seal ring is sealing engaged with the sump housing and has a radially inward facing seal surface that sealingly engages the radially outward facing seal surface of the runner. The runner and the seal ring are formed from materials having coefficients of thermal expansion that are matched to effect sealing engagement between the runner and the seal ring over a predetermined range of operating temperatures.

A non-contact seal assembly includes a plurality of seal shoes, a seal base and a plurality of spring elements. A first of the spring elements includes a first mount, a second mount and a spring beam. The spring beam extends a length longitudinally along a centerline from the first mount to the second mount. The spring beam includes opposing first and second surfaces. The first surface is disposed a first distance from the centerline, and the second surface is disposed a second distance from the centerline. The first distance and the second distance change as the spring beam extends longitudinally along the centerline to provide at least a portion of the spring beam with a tapered geometry. The portion of the spring beam has a longitudinal length that is at least about five percent of the length of the spring beam.

A valve assembly includes a valve body having a seat-retainer chamber with a floating seat ring disposed adjacent an inner sidewall of the seat-retainer chamber. The floating seat ring is configured to contact a first portion of a plug head at a single annular location prior to a second portion of the plug head contacting a valve primary seat during a closing stroke of the plug head. A static seal is located radially between the floating seat ring and the inner sidewall of the seat-retainer chamber.