A compression unit of a rotary compressor includes a cylinder, an upper end plate that closes the upper side of the cylinder, a lower end plate that closes the lower side of the cylinder, and a piston that is fitted to a rotating shaft, revolves along an inner peripheral surface of the cylinder, and forms a cylinder chamber in the cylinder. At least one of an end face of the piston in the axial direction of the rotating shaft, a sliding surface of the upper end plate that slides with the end face of the piston, and a sliding surface of the lower end plate that slides with the end face of the piston, has formed therein an oil-film retention region having an array of a plurality of recessed portions that retain lubricating oil.

A downhole-type device includes an electric machine. The electric machine includes an electrical rotor configured to couple with a device to drive or be driven by the electric machine. An electrical stator surrounds the electric rotor. The electric stator includes a seal configured to isolate stator windings from an outside, downhole environment. An inner surface of the seal and an outer surface of the electric rotor define an annulus exposed to the outside environment. A bearing couples the electric rotor to the electric stator. A lubrication system is fluidically coupled to the downhole-type device. The lubrication system includes a topside pressure pump and a downhole-type distribution manifold configured to be used within a wellbore. The distribution manifold is fluidically connected to the topside pressure pump and the bearing to receive a flow of lubricant from the topside pressure pump.

Refrigerant compressor with a hermetically sealed housing and a drive unit in the interior of the housing. At least one damping element is in the housing is connected to the drive unit. The damping element has three contact areas separated from each other by an edge, in which in a first deflected state of the drive unit a first contact area contacts a first inner surface area of the housing, wherein in a second deflected state a second contact area contacts a second inner surface area of the housing, but the first contact area does not contact the first inner surface area, wherein in a third deflected state of the drive unit a third contact area contacts a third inner surface area, but the first and second contact areas do not contact the first and second inner surface areas, respectively.

An internal oil filter is installed at least partially inside a crankcase and/or an oil sump of a compressor. The internal oil filter can receive oil from an oil pressure regulator and filter the oil via filter media. The received oil radially penetrates through the filter media and flow directly into the oil sump from an outside surface of the filter media. This can eliminate the need of fluid lines connecting an outlet of an oil filter to the oil sump and any sealing mechanism therebetween.

A packing case for a plunger or a piston rod of a reciprocating machine comprises packing cups, each packing cup comprising a body with a hole for the passage of the plunger or rod and a sealing ring seat for housing a sealing ring which slidably bear against the plunger or rod. Packing cups are aligned with each other in series. The packing case comprises lube oil ducts for supplying lube oil from an end of the packing case to the sealing ring seat. Each packing cup comprises sectors, each sector comprising at least lube oil duct portions. The packing cups are positionable to bring, one sector at a time in an activation position where some of the lube oil duct portions of the sector are connected with the lube oil duct portions of an adjacent packing cup to form lube oil ducts. The packing cups are lockable.

An air compressor pump is provided, including a crankcase with an opening and a crankshaft extending out of the opening; a cover disposed over the opening in the crankcase; and a condensing chamber formed between the crankcase and the cover.

Lubricating oil has a kinematic viscosity in a range of 1 mm.sup.2/S to 7 mm.sup.2/S at 40° C., has a mass average molecular weight in a range of 150 to 400, and contains 0.5% by mass or more of a high molecular weight component. The high molecular weight component has a mass molecular weight of greater than or equal to 500. A crankshaft serving as a shaft part of a compression element includes a main shaft that includes a sliding surface. In a case where the sliding surface is a single sliding surface, a length of the single sliding surface in an axial direction is a single sliding length L, whereas in a case where the sliding surface is divided into a plurality of sliding surfaces, a length of one of the sliding surfaces in the axial direction, the one sliding surface having a least length in the axial direction among the plurality of sliding surfaces, is the single sliding length L, and a ratio L/D of the single sliding length L to an external diameter D of the main shaft is less than or equal to 2.0.

In a hermetic refrigerant compressor, a thrust bearing (e.g., thrust ball bearing (210)) is provided on a thrust surface (136) of a main bearing (134). One end of a sliding surface of the main bearing (134), the one end being closer to a compression chamber (133) than an opposite end of the sliding surface, is a first end, and the opposite end of the sliding surface is a second end. A distance between a center axis of the compression chamber (133) and the second end of the sliding surface (sliding surface lower end (139)) of the main bearing (134) is a distance L, and a distance between the center axis of the compression chamber (133) and the first end of the sliding surface (sliding surface upper end (138)) of the main bearing (134) is a distance La. When the distance L is in a range of 38 mm to 51 mm, the distance La is less than or equal to 16 mm.

An oil separator for a compressor comprising a tank and a lid for the tank, which comprises, in an integral manner, a valve body defining an outlet duct of the separator, a head of a coalescence filter, a body of an anti-condensate valve, a body of a minimum pressure valve and the relative connection ducts.

An oil separator for a compressor comprising a tank and a lid for the tank, which comprises, in an integral manner, a valve body defining an outlet duct of the separator, a head of a coalescence filter, a body of an anti-condensate valve, a body of a minimum pressure valve and the relative connection ducts.