A pump system (120) has a central pump unit (110), with which at least one hook-up unit (130). The at least one hook-up unit (130) is from a group of a plurality of hook-up units (130) that can be combined in modular form for setting an operating point of a pump (10) that forms the pump unit (110). A method uses such a hook-up unit (130) in a pump system (120) for setting an operating point of the pump unit (110) thereof. A medical device is provided with such a pump unit (110) or with such a pump unit (110) and at least one hook-up unit (130) combined with the pump unit (110).

A reciprocal compressor includes a cylinder, a piston inside the cylinder and including an upper wall constituting a compression chamber and a lateral wall formed to extend from the upper wall, an elastic cover provided so that an outer surface of the upper wall of the piston is between the piston and the elastic cover, and a cam mechanism configured to deform the elastic cover into a first state in which the elastic cover is apart from the upper wall of the piston to reduce a volume of the compression chamber and to restore the elastic cover into a second state in which the elastic cover is closer to the upper wall of the piston than in the first state while the piston is moved to a top dead center and a bottom dead center.

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. The seal element is sized to be installed around the closure element and includes a repositionable seal. The repositionable seal is movable axially with respect to the closure element so that the repositionable seal can be positioned in multiple sealing positions.

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. The seal element is sized to be installed around the closure element and includes a repositionable seal. The repositionable seal is movable axially with respect to the closure element so that the repositionable seal can be positioned in multiple sealing positions.

An oil wiper packing for a piston rod of a crosshead piston compressor, and corresponding assembly method. The oil wiper packing has at least one chamber disc having a chamber disc cutout, wherein a wiper ring arranged in the chamber disc cutout. At least two chamber discs, each having a chamber disc cutout, are arranged in succession in a direction of extent (L), and a single wiper ring is in each chamber disc cutout. Each wiper ring has no play or only negligible play in the direction of extent (L) in the operating state but is movable in the radial direction. It is necessary to set the play in in the cold state during the assembly of the wiper rings. Such an arrangement allows advantageous wiping of oil, preventing oil from spreading in the direction of extent of the piston rod.

A vibration body unit includes: a vibration body; an inner cylinder that surrounds a circumference of the vibration body and that is elastically deformable; an outer cylinder that surrounds a circumference of the inner cylinder and that has an attachment section which is attached to a base part; a plurality of first spacers that are interposed between the vibration body and the inner cylinder and that are arranged to be spaced in a circumferential direction; and a plurality of second spacers that are interposed between the inner cylinder and the outer cylinder and that are arranged to be spaced in a circumferential direction, wherein the plurality of first spacers and the plurality of second spacers are arranged such that at least part of each of the plurality of first spacers faces each of the plurality of second spacers in a radial direction across the inner cylinder.

A linear compressor includes a discharge valve detachably attached to a front end surface of a cylinder to open and close a compression space of the cylinder; and a valve spring elastically supporting a rear surface of the discharge valve to press the discharge valve toward the front end surface of the cylinder. The discharge valve includes reinforced fiber, and the reinforced fiber is arranged parallel to the front end surface of the cylinder. Accordingly, while a rigidity of the discharge valve is improved, a weight of the valve is reduced to enhance responsiveness of the valve, suppress abrasion of the cylinder, and reduce striking sound.

A silencing device and a compressor having the silencing device are disclosed. The silencing device has a housing. An air inlet and an air outlet are provided to the housing. An air flow channel is provided in the housing for allowing air communication between the air inlet and the air outlet. An oil hole is provided in the housing for discharging oil from the housing. An oil guide part is arranged on the outside of the housing and at a position downstream of the oil hole in the moving direction of the oil, such that the oil drips from the housing after flowing from the oil hole to the oil guide part.

A natural gas pumping system that includes six reciprocating compressor cylinders, the reciprocating pistons of the six compressors having cycles offset by 60 degrees one from another.

A method of attenuating pressure pulsations, comprises: pumping liquid into a vessel in fluid communication with a flow line by a conduit sealingly passing through a top surface of the vessel, so as to discharge the liquid into the flow line while creating an air-liquid interface in the vessel, by trapping in an upper part of the vessel air that attenuates pressure pulsations caused by the pumping. The method also comprises generating condition for the liquid to drain out of the vessel to allow air to fill at least the upper portion of the vessel.