A piston pump as a high-pressure fuel pump of a common rail system includes: a pump cylinder; a pump piston moveably mounted in a recess of the pump cylinder, the pump piston being moveable up and down in the recess; and a leakage groove arranged in the pump cylinder in a region of the recess, the leakage groove being coupled with a leakage line configured to discharge a fuel leakage. Between the pump cylinder and the pump piston a different size pairing clearance is formed in first and second portions of the pump cylinder.

A linear compressor includes a cylinder that defines a compression space of a refrigerant and has a cylindrical shape, and a piston disposed in the cylinder and reciprocating along an axis of the cylinder. The cylinder includes a gas inlet on an outer circumferential surface and a supply port radially passing through the cylinder and communicating with the gas inlet. The gas inlet includes a first gas inlet and a second gas inlet disposed behind the first gas inlet, and the supply port includes a first supply port communicating with the first gas inlet and a second supply port disposed behind the first supply port and communicating with the second gas inlet. A flow rate passing through the first supply port is different from a flow rate passing through the second supply port.

A linear compressor is provided. The linear compressor may include a cylinder that defines a compression space for a refrigerant; a piston that axially reciprocates inside the cylinder; a motor configured to provide a drive force to the piston; a discharge valve configured to discharge the refrigerant compressed in the compression space; and a discharge cover having a discharge space in which the refrigerant discharged through the discharge valve flows. The discharge valve and the discharge cover may be arranged inside the motor.

Structural simplification and efficient injection state of high-pressure air from a nozzle are ensured. A foreign material removal device is provided with: a cylinder (18) into which air is caused to flow; a piston (22) which is movably supported in the cylinder and feeds the air introduced into the cylinder in a feeding direction as high-pressure air; and a nozzle (6) which injects the high-pressure air fed by the piston. Thus, the piston is moved relative to the cylinder, the high-pressure air is fed from the cylinder, and the high-pressure air is injected from the nozzle, whereby structural simplification and an efficient injection state of the high-pressure air from the nozzle can be ensured.

A high pressure homogenizer for flowable substances charged with particles, having a high pressure chamber and a homogenizer unit that is located fluidically downstream thereof and, by swirling, expands the fluid to be homogenized which has previously been brought to a pressure of more than 500 bar in the high pressure chamber, and a plunger pump associated with the homogenizer unit, the plunger of which plunger pump pressurizes the high pressure chamber, wherein the high pressure homogenizer has a low pressure chamber which surrounds the plunger shaft to cool the plunger and which has an operating pressure of P.sub.N≤25 bar, wherein the low pressure chamber and the high pressure chamber are separated from each other by a seal which is penetrated by the plunger, the seal being a throttle gap which is formed between the plunger shaft and a bushing that does not contact the plunger shaft, the ratio S/.sub.L of the length to the radial annular gap height of the throttle gap being ≤0.0015.

A system for dispensing abrasive materials includes a transfer pump configured to pump abrasive material to a metering pump configured to pump the abrasive material to an application. Dynamic interfaces within the pumps are at least partially formed by sleeved components of the pump interfacing with a seal configured to engage with the sleeved surface during relative movement between the sleeved surface and the seal. The smooth exterior surfaces of the sleeves interface with the seals to prevent abrasive particulate in the material from adhering to the sleeve, preventing the abrasive particulate from being pulled between the sleeve and the seal.

A reciprocating pump includes a fluid end having a body defining a plunger bore that engages a plunger sleeve with a threaded interface, where the plunger sleeve defines throughbore configured to receive a plunger operatively reciprocating within the plunger bore during operation of the reciprocating pump. A packing assembly including a plurality of stacked annular seals is disposed between the plunger sleeve and the plunger. A packing nut having a threaded profile for engagement with a threaded surface of the plunger bore asserts a load against the packing assembly to ensure a positive engagement with the plunger.

A linear compressor includes a cylinder that defines a compression space of a refrigerant and has a cylindrical shape, and a piston disposed in the cylinder and reciprocating along an axis of the cylinder. The cylinder includes a gas inlet on an outer circumferential surface and a supply port radially passing through the cylinder and communicating with the gas inlet. The gas inlet includes a first gas inlet and a second gas inlet disposed behind the first gas inlet, and the supply port includes a first supply port communicating with the first gas inlet and a second supply port disposed behind the first supply port and communicating with the second gas inlet. A flow rate passing through the first supply port is different from a flow rate passing through the second supply port.

A precision volumetric pump with a bellows hermetic seal provides compliance time performance comparable to a conventional pump having a dynamic seal. However, the precision volumetric pump with a bellows hermetic seal is enabled to operate over a very long service life with minimal or no maintenance without a propensity to develop leaks over the long service life.

The present invention relates to a drug delivery device that houses a piston equipped cartridge and a drive mechanism comprising a piston rod (170) configured for axially moving the piston in a distal direction. An adjustment member (150) connects to the member (150) comprises a first contour system (175) defining a plurality of steps (175′, 175″, 175′″) being circumferentially disposed and arranged axially offset from one another. The other of the piston rod (170) and the adjustment member (150) comprises at least one radially disposed protrusion (155). For eliminating an axial clearance between the piston rod (170) and the piston of the cartridge the at least one radially disposed protrusion (155) axially engages a selective one of said plurality of steps (175′, 175″, 175′″) so that the relative rotational position between the piston rod (170) and the adjustment member (150) is decisive for the axial position of the adjustment member (150) relative to the piston rod (170).