A fluid working machine comprises a rotor (7) with a blading (10) comprising 40 to 65 blades that radially project out of a body central and are suitably circumferentially offset on a plane normal to the axis of symmetry of the rotor, according to an appropriate spacing rule that can eliminate or appreciably attenuate the acoustic emission components that are mostly annoying to the human ear or at frequencies close to the resonance frequencies of other parts of the working machine.

A fluid pump includes an inlet for introducing fluid into the fluid pump and an outlet for discharging the fluid from the fluid pump A motor is included having an armature which rotates about an axis. The motor also has a stator which circumferentially surrounds the armature such that a fluid passage is defined radially between the armature and stator through which the fluid flows from the inlet to the outlet. A pumping arrangement is rotated by the armature and pumps the fluid from the inlet to the outlet. A flow impedance member extends axially in the fluid passage which impedes circumferential flow of the fluid within the fluid passage, thereby generating a pressure gradient circumferentially within the fluid passage which applies a lateral force to the armature.

A fluid pump includes an inlet for introducing fluid into the fluid pump and an outlet for discharging the fluid from the fluid pump. A motor is included having an armature which rotates about an axis The motor also has a stator which circumferentially surrounds the armature such that a fluid passage is defined radially between the armature and stator through which the fluid flows from the inlet to the outlet. A pumping arrangement is rotated by the armature and pumps the fluid from the inlet to the outlet A flow impedance member extends axially in the fluid passage which impedes circumferential flow of the fluid within the fluid passage, thereby generating a pressure gradient circumferentially within the fluid passage which applies a lateral force to the armature.

A fuel delivery pump for delivering fuel, having an electric motor and having a pump impeller that is driven by means of the electric motor, wherein the pump impeller is connected by means of a shaft to a rotor of the electric motor such that a rotational movement of the rotor is transmitted via the shaft to the pump impeller, wherein the shaft is mounted by means of an axial bearing in an axial direction and/or by means of a radial bearing in a radial direction relative to a pump stage in which the pump impeller is arranged, wherein an electrical insulation element is arranged between the axial bearing and the pump stage, and/or an electrical insulation element is arranged between the radial bearing and the pump stage.

A fluid pump includes an inlet for introducing fluid into the fluid pump; an outlet for discharging the fluid from the fluid pump; a motor having an armature which rotates about an axis such that the armature is supported at one end by a first bearing and at second end by a second bearing, the motor also having a stator which circumferentially surrounds the armature such that a fluid passage is defined radially between the armature and stator through which the fluid flows from the inlet to the outlet; a pumping arrangement which is rotated by the armature and which pumps the fluid from the inlet to the outlet; a flow impedance member extending axially in the fluid passage which impedes circumferential flow of the fluid within the fluid passage, thereby generating a pressure gradient circumferentially within the fluid passage which applies a lateral force to the armature.

A sealing ring gland receives a sealing ring. The sealing ring gland includes an inner wall surface which seals against an inner periphery of the sealing ring. An outer wall surface is radially offset from the inner wall surface and seals against an outer periphery of the sealing ring. The sealing ring is axially compressed between an upper wall surface and a lower wall surface of the sealing ring gland. At least one of the upper wall surface and the lower wall surface includes an expansion volume which provides space for the sealing ring to expand upon swelling of the sealing ring.