A centrifuge turbo machinery includes an impeller which rotates about an axis to pressure-feed fluid flowing along the axis to an outer side in a radial direction, and a casing which accommodates the impeller and has a facing surface facing the impeller in an axial direction. A convex portion relatively close to the impeller and extending in the radial direction and a concave portion relatively spaced apart from the impeller and extending in the radial direction are alternately and continuously formed on the facing surface in a circumferential direction.

An improved rotary machine of the invention may include a rotor with an impeller mounted thereon. A side cavity may be formed between an impeller and the housing. The rotary machine may be further equipped with an annular subdividing disc for segmenting a fluid flow in the cavity into a first fluid flow between the disc and the impeller, and a second fluid flow on the other side of the disc between the disc and the housing. The rotary machine of the invention also features a peripheral annular space formed in the periphery of the housing in the cavity at a location adjacent to a peripheral region of the annular subdividing disc. Importantly, this peripheral annular space is void of restrictions to circumferential fluid flow therein so as to alter the second fluid flow in the cavity in order to reduce pressure variations and flow disturbances along the circumference of the rotary machine. This in turn improves rotational balance of the rotary machine.

Embodiments of the invention are directed to a rotor for a molten metal pump and a molten metal pump including the rotor. The rotor has a main body and a top comprised of a material that is at least twice as hard as the main body. The top, among other things, may form a first portion of each rotor blade wherein the first portion directs molten metal into a pump chamber or other structure in which the rotor is mounted.

An impeller for use in an aquarium filter pump includes a shaft and a plurality of impeller blades radially extending from the shaft. Each of the impeller blades includes opposite blade faces. A depression is in each of the blade faces and aids in pushing the water. The depression can be a variety of shapes and can have its deepest portion along one of the edges of the blade.

Embodiments of the invention are directed to a rotor for a molten metal pump and a molten metal pump including the rotor. The rotor has a main body and a top comprised of a material that is at least twice as hard as the main body. The top, among other things, may form a first portion of each rotor blade wherein the first portion directs molten metal into a pump chamber or other structure in which the rotor is mounted.

An impeller in which blades and a shroud are bonded in a stable manner. The impeller is provided with a plurality of blades disposed on a base, and a shroud disposed facing the base across the blades. The shroud has a curved shape, wherein the shroud has a flat part in the outer periphery, protuberances are provided to flat surfaces of the blades, through-holes are provided to the flat part of the shroud, and, after the protuberances are inserted through the through-holes, the flat surfaces of the blades and the flat part of the shroud are bonded together by deforming the tips of the protuberances into thermally caulked parts larger in diameter than the opening diameters of the through-holes.

An impeller for use in an aquarium filter pump includes a shaft and a plurality of impeller blades radially extending from the shaft. Each of the impeller blades includes opposite blade faces. A depression is in each of the blade faces and aids in pushing the water. The depression can be a variety of shapes and can have its deepest portion along one of the edges of the blade.

A motor-driven water lifting device of which the water lifting device includes housing having water-lifting wheel mounted in accommodation chamber therein, water supply pipe disposed at the periphery of the housing and having water inlet for guiding water into accommodation chamber and water outlet for guiding water out of accommodation chamber, and air inlet hole located on water supply pipe for allowing an external gas to be filled into accommodation chamber of housing so that when water is guided through the water inlet into accommodation chamber, the intake water is agitated by the water-lifting wheel and mixed with the external gas in the accommodation chamber to form a bubble water. The water molecules of the bubble water are finely mixed by mixing with the gas, and the fine bubble water is suitable for cleaning various objects to achieve an optimized cleaning effect.

An impeller for use in an aquarium filter pump includes a shaft and a plurality of impeller blades radially extending from the shaft. Each of the impeller blades includes opposite blade faces. A depression is in each of the blade faces and aids in pushing the water. The depression can be a variety of shapes and can have its deepest portion along one of the edges of the blade.

A method of making an impeller includes building the impeller in a layer by layer process in a build direction along the rotational axis starting from a base of the hub. The plurality of blades includes a plurality of perforated blades that support the shroud during additively manufacturing the impeller. The method can include installing the impeller in a fuel pump, air compressor, or the like, without removing the perforated blades from the impeller.