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 compressor is provided. The reciprocating compressor may include a cylinder having a compression space, a piston inserted into the cylinder to define the compression space while being reciprocated, the piston having a suction passage to communicate with the compression space, a gas bearing having at least one bearing hole that passes through the cylinder, so that a refrigerant gas may be injected between the cylinder and the piston to support the piston with respect to the cylinder, and a flow resister disposed at an outer circumferential surface of the cylinder or at one side of the cylinder to restrict a flow of the refrigerant gas flowing through or toward the at least one bearing hole.

A reciprocating compressor is provided. The reciprocating compressor may include a cylinder having a compression space, a piston inserted into the cylinder to define the compression space while being reciprocated, the piston having a suction passage to communicate with the compression space, a gas bearing having at least one bearing hole that passes through the cylinder, so that a refrigerant gas may be injected between the cylinder and the piston to support the piston with respect to the cylinder, and a flow resister disposed at an outer circumferential surface of the cylinder or at one side of the cylinder to restrict a flow of the refrigerant gas flowing through or toward the at least one bearing hole.

A pump for reducing agents of an exhaust gas purification system for an internal combustion engine of a motor vehicle includes: a diaphragm carrier; a diaphragm arranged on the diaphragm carrier, the diaphragm having a radially outer collar; and a pump housing configured to secure the radially outer collar of the diaphragm. The radially outer collar of the diaphragm has a reinforcing ring.

A gas bearing is disclosed. The gas bearing may include a cylinder with an inner cylinder radius. The gas bearing may include a piston with a piston radius, wherein the inner cylinder radius is larger than the piston radius, wherein the piston is located within the cylinder. The gas bearing may include a gas bearing radius, wherein the gas bearing radius is greater than the piston radius and less than the inner cylinder radius. The gas bearing may include a gap that exists between the cylinder and the piston, wherein the gap contains a pressurized gas, the pressurized gas configured to prevent contact between the cylinder and the piston. The gas bearing may include a gas bearing interface, wherein the gas bearing interface is positioned to control a size of the gap.

An implantable infusion device includes a reservoir for housing an infusion medium and a drive mechanism having an inlet chamber, a piston and a piston channel. The inlet chamber is in fluid communication with the reservoir. The piston channel is in fluid communication with the inlet chamber, and has a distal end and a proximal end, the proximal end being closer to the inlet channel than the distal end. The piston is axially moveable within the piston channel to drive infusion medium out of the distal end of the piston channel. The clearance between the piston and the channel is sufficiently small to prevent undissolved gas in the inlet chamber from passing through the clearance. The inlet chamber may be sufficiently large to allow undissolved gas to accumulate without adversely affecting the performance of the infusion device.

Systems and methods for operating a linear motor (e.g., for an ESP), where the motor's mover moves in a reciprocating motion within a bore of the stator. Hard stops are located at the ends of the bore. The motor has a first set of sensors in the stator positioned proximate to the bore. When the mover moves in the bore, the sensors produce corresponding output signals, except when the mover is in a position near, but not in contact with a hard stop. While the sensors produce output signals, the motor is driven in a first direction toward the hard stop. When the sensors stop producing the output signals, the mover has reached the first position, and the motor is controlled to reverse the direction of the mover.

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.

A high pressure pump for delivering a fluid includes a pump housing with a longitudinal axis and a housing cavity, a piston partly arranged in the housing cavity and axially moveable within the housing cavity and having an axial end directed opposite a driving side of the high pressure pump, and a sealing unit having a sealing body arranged radially outside of the piston such that a first part of the housing cavity is sealed fluid-tight against a second part of the housing cavity. The sealing body includes a neck with an inner diameter smaller than a first diameter of a part of the piston arranged between the sealing body neck and the axial end of the piston. The piston has a second diameter in an axial area in which the sealing body neck is arranged, which second diameter is smaller than the first diameter.

A pump piston is disclosed. The pump piston may include a body having an actuating end, a pressurizing end opposite the actuating end, and an outer diameter that is greater at the pressurizing end than at the actuating end, wherein the outer diameter varies between the pressurizing end and the actuating end without increasing to form an outer diameter profile.