The present disclosure relates to a pumping assembly, a piston pump and an oral irrigator. The pumping assembly includes: a cylinder, cavities providing therein with at least two cavities with different inner diameters; a piston mechanism successively extending through the at least two cavities, the piston mechanism being in slidable cooperation with walls of the cavities, and a gap being formed between a sidewall of part of the piston mechanism and the walls of the cavities; and a drive mechanism connected to the piston mechanism, the drive mechanism being configured to drive the piston mechanism to move.

Various assemblies that can be used in a mud pump with a plunger-style piston to reduce seal failures, to offer control in variability of the circumference of the piston to thereby control fluid pressure, and to provide visibility into seal condition during operation. In one embodiment, a sleeve that can vary the overall effective circumference of the piston enables fluid pressure control. In some embodiments, seal failure within a pump can be monitored via a drain port that would receive drilling fluid leaking past a seal during operation of the pump. A discharge valve can be provided between an inlet and an outlet of the mud pump to reduce the load on pump components during start-up. Additional systems, devices, and methods are also disclosed.

In order to avoid over-lubrication of the cylinders (2) in a piston compressor (1) and to reduce the amount of lubricant to a level required for operation, according to the invention, a lubricating system having a lubricating system control unit (14) is provided, in which system at least one lubricant sensor (15) is provided for detecting a lubricating film measurement variable (S) representative of a lubricating film thickness of a lubricating film (11) on the cylinder surface of the cylinder (2), the lubricating system control unit (14) being designed to operate the lubricating system at least once in a predetermined calibration operating mode during operation of the piston compressor (1) and to determine a lubricating film state value (SZ) on the basis of the lubricating film measurement variable (S) detected during execution of the calibrating operating mode and the lubricating system control unit (14) being designed, after the end of the calibration operating mode during operation of the piston compressor (1), to control the amount of lubricant to be introduced depending on the determined lubricating film state value (SZ).

The piston compressor for compressing a gas having a cylinder and also including a piston, a piston rod, packing, a crosshead and a drive, wherein: the piston is disposed for movement in a longitudinal direction L inside the cylinder; the piston is connected to the crosshead by means of a piston rod; packing is disposed between the piston and the crosshead, through which packing the piston rod runs; the crosshead is driven by the drive; in addition an activatable magnetic bearing is disposed between the piston and the crosshead; the magnetic bearing can generate a magnetic force F.sub.m on the piston rod, at least perpendicularly to the longitudinal direction L; and an activation device activates the magnetic force F.sub.m generated by the magnetic bearing on the piston rod.

A positive displacement machine includes a case including a tubular guide part in which a pressure chamber is provided, a slide member including a shaft extending in a first direction and a piston provided at an end portion of the shaft and disposed in the guide part, a coupling member coupled to the slide member and extending in a second direction intersecting the first direction, a first rotating member coupled to one end of the coupling member and configured to rotate around a first rotation axis extending in the second direction, and a rocking absorbing mechanism configured to absorb a rocking motion of the piston around an axis extending in the first direction. The rocking absorbing mechanism is provided between the coupling member and the slide member, between the shaft and the piston, or between the piston and an inner wall of the guide part.

The piston ring assembly having a first and a second endless sealing ring and an elastic ring carrier, the first and the second sealing ring extending in a circumferential direction (U) and each having an outer circumferential surface, the first sealing ring having a first center point (M1) with respect to its outer circumferential surface and the second sealing ring having a second center point (M2 ) with respect to its outer circumferential surface, the first and second sealing rings each having a longitudinal axis (L) running perpendicular to the circumferential direction (U), wherein the ring carrier runs in the circumferential direction (U), and wherein the ring carrier and the first and second sealing rings are designed to be mutually adapted in such a way that the first and second sealing rings are arranged one after the other in the ring carrier in the direction of the longitudinal axis (L), and in that their first and second centers (M1, M2) are arranged at a distance from one another radially with respect to the longitudinal axis (L), the sealing rings being pressed in opposite directions against the inner wall of a cylinder when the piston ring assembly is used in accordance with the invention.

A tangentially cut rod packing ring is provided. The tangentially cut rod packing ring comprises a first ring formed from a plurality of segments. Each of the segments has a portion of two interfaces where each interface slidably engages an interface of an adjacent segment. One interface terminates at a leading surface. One interface has a stop surface. The leading surface is originally separated from the stop surface by a gap. As the interfaces slidably move, the gap lessens until the leading surface abuts the stop surface. The tangentially cut rod packing ring also comprises a second ring formed from a plurality of segments. The second ring has a first portion and a second portion. The first portion forms as shelf on which the first ring sits. The second portion surrounds the first ring. An elastic member in a groove on the outer surface of the second portion provides a compressive force on both the second ring and the first ring.

The subject application relates to a cupseal for a compressor and method for preparing the same. Systems and methods are disclosed that include providing an annular seal for a compressor. The annular seal includes a substantially planar first portion, a first angled portion extending at an angle from the substantially planar first portion, and a second angled portion extending radially at an angle from the first angled portion. The annular seal is formed from a fluorinated polymer and includes at least one additive or filler. The annular seal exhibits reduced wear and an increased lifespan.

A piston ring includes a first ring portion which is fitted onto an outer circumferential portion of a piston and which is capable of sliding relative to an inner wall surface of a cylinder, and a second ring portion which is fitted onto the outer circumferential portion of the piston, arranged side-by-side with the first ring portion in the axial direction, and which is capable of sliding relative to the inner wall surface of the cylinder. The second ring portion is fitted onto the outer circumferential portion of the piston in such a way as to be positioned on a side opposite to a compression chamber inside the cylinder, relative to the first ring portion, and has a greater hardness than the first ring portion has.

A piston assembly for a piston pump includes an actuator rod, a piston coupled to the actuator rod and configured to contact a radially-inner wall of a cylinder, and a piston support structure coupled to the actuator rod and configured to contact the radially-inner wall of the cylinder. A fluid channel extends through the actuator rod and the piston support structure, and the fluid channel is configured to deliver a lubricating fluid to an annular space positioned between the piston and the piston support structure along an axial axis of the piston assembly.