An air sampling pump includes a reciprocating piston for operating a diaphragm assembly. The diaphragm includes a valve head including a fluid inlet and a fluid outlet and a fluid chamber defining a fluid path between the inlet and outlet. A diaphragm sealing engages the valve head and encloses the fluid chamber. The diaphragm includes a piston diaphragm membrane portion coupled to the piston for reciprocating with the piston and reciprocation of the piston causes a change in air pressure within the fluid chamber to cause air to move from the fluid inlet toward the fluid outlet. The diaphragm includes a damper membrane portion, which cooperate to reduce an amplitude of pulsation in the airflow at the fluid inlet and fluid outlet.

A reciprocating compressor includes a piston slidably mounted within a compression chamber and defining a suction port for receiving a flow of gas. A flex mount is mechanically coupled to the piston and has an inner surface that defines a suction cavity. A suction muffler is positioned at least partially within the suction cavity and includes an inlet tube extending along the axial direction within the suction cavity and defining an inlet passageway configured to receive the flow of gas and a plurality of chamber plates that extend along the radial direction from an outer surface of the inlet tube, the plurality of chamber plates and the flex mount defining a plurality of resonance chambers to reduce compressor noise.

An air sampling pump includes a reciprocating piston for operating a diaphragm assembly. The diaphragm includes a valve head including a fluid inlet and a fluid outlet and a fluid chamber defining a fluid path between the inlet and outlet. A diaphragm sealing engages the valve head and encloses the fluid chamber. The diaphragm includes a piston diaphragm membrane portion coupled to the piston for reciprocating with the piston and reciprocation of the piston causes a change in air pressure within the fluid chamber to cause air to move from the fluid inlet toward the fluid outlet. The diaphragm includes a damper membrane portion, which cooperate to reduce an amplitude of pulsation in the airflow at the fluid inlet and fluid outlet.

An electrical motor vehicle vacuum pump arrangement includes a housing assembly which includes an inlet opening arrangement having an inlet opening, an outlet opening arrangement having an outlet opening and an outlet channel, a pump unit having a pump rotor housing with an inlet-side end wall, an outlet side end wall, and a pump rotor housing part arranged therebetween, a drive motor having a motor rotor and a motor stator, sound absorption elements, and a sealing connected to the pump rotor chamber and directed towards the outlet opening. The outlet opening arrangement is connected to one of the sound absorption elements. The outlet channel of the outlet opening arrangement is closed relative to the drive motor and the pump unit. The outlet channel of the outlet opening arrangement, when viewed in a direction of the outlet opening, comprises at least one abrupt change in cross-section.

A valve includes: a first plate having a first vent hole; a second plate having a second vent hole; a valve chamber positioned between the first plate and the second plate; a valve body including a third vent hole; an exhaust path-forming plate forming a first flow path between the exhaust path-forming plate and the valve body, forming a second flow path between the exhaust path-forming plate and the second plate, and having a fourth vent hole through which the first flow path is in communication with the second flow path; and a fifth vent hole. The first flow path establishes communication between the second vent hole and the fourth vent hole, and the second flow path establishes communication between the fourth vent hole and the fifth vent hole.

A compressor is configured to compress a fluid. The compressor includes a first casing and at least one first pipe. The first casing is electrically conductive. The at least one first pipe is electrically conductive. The at least one first pipe is fixed to the first casing with a first insulator interposed therebetween.

A portable oxygen concentrator includes a compressor and a controller. The compressor includes a motor, at least one chamber, and at least one piston operably coupled to the motor and movable within the at least one chamber. In some embodiments, the controller is configured to: determine actual motor speeds for commutations steps of the motor during a first rotational cycle; determine an average motor speed during the first rotational cycle; determine a voltage pattern based at least on a comparison of the average motor speed during the first rotational cycle and the actual motor speeds for the commutation steps of the motor during the first rotational cycle; and cause the voltage pattern to be applied to the motor during a second rotational cycle to reduce differences between applied motor torque and variable torque load imparted by the at least one piston.

A compressor is disclosed, which comprises a case, a cylinder disposed inside the case, a piston moving inside the cylinder, and a muffler provided in the piston. The muffler includes a fluid pipe provided with a resonant space formed between an outer circumferential surface and an inner circumferential surface of the piston, and a guide panel protruded from the outer circumferential surface of the fluid pipe to the inner circumferential surface of the piston and extended along an outer circumferential direction of the fluid pipe. The guide panel is provided in a plural number, and is partially opened along the outer circumferential direction of the fluid pipe to form an open area, and the open area formed in any one guide panel is covered by its adjacent guide panel.

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.

A multi-pump pump system includes at least two pumps and a system pulsation dampener sized and configured to reduce a magnitude of pressure pulsations within a combined flow output by the at least two pumps, together with at least one mini-dampener coupled between the outlet of one of the pumps and header pipe(s) carrying flow from one of the pumps into the system pulsation dampener, the at least one mini-dampener sized and configured to reduce the magnitude of pressure pulsations over the system pulsation dampener alone. Optionally, a mini-dampener may be coupled between each pump and the system pulsation dampener. A single header pipe may carry combined flow from the at least two pumps into the system pulsation dampener, or separate header pipes may carry individual flows from the pumps into the system pulsation dampener.