A pump comprises: a vertically-extending conduit having an intermediate portion extending between lower and upper portions, the intermediate portion having a cross-sectional area smaller than that of the upper portions, a lift arrangement including an array of ports arranged over a length of the lower portion, each port of the array having a terminus at the lower portion and extending horizontally away from the terminus such that the working fluid is directed towards a center of the conduit; and an injector having a terminus at the top of the intermediate portion and extending vertically downwardly such that the working fluid is directed vertically upwardly, the terminus of the injector being defined by a cylindrical groove, an annular chamber surrounding the injector, having a length and communicating with the injector through a row of apertures spaced a distance from the junction of the transition portion and the intermediate portion.

A pump comprises: a vertically-extending conduit having an intermediate portion extending between lower and upper portions, the intermediate portion having a cross-sectional area smaller than that of the upper portions, a lift arrangement including an array of ports arranged over a length of the lower portion, each port of the array having a terminus at the lower portion and extending horizontally away from the terminus such that the working fluid is directed towards a center of the conduit; and an injector having a terminus at the top of the intermediate portion and extending vertically downwardly such that the working fluid is directed vertically upwardly, the terminus of the injector being defined by a cylindrical groove, an annular chamber surrounding the injector, having a length and communicating with the injector through a row of apertures spaced a distance from the junction of the transition portion and the intermediate portion.

A multi-stage ejector is provided for producing vacuums in an industrial process and includes at least two ejector units axially arranged at a predetermined distance apart in an ejector housing. Each of the at least two ejector units includes at least two parallelly arranged hollow feed-throughs for compressed air, including inlet and outlet nozzles and at least one hollow feed-through for vacuum. Each of the at least two ejector units is configured as a part produced from one piece.

A multi-stage ejector is provided for producing vacuums in an industrial process and includes at least two ejector units axially arranged at a predetermined distance apart in an ejector housing. Each of the at least two ejector units includes at least two parallelly arranged hollow feed-throughs for compressed air, including inlet and outlet nozzles and at least one hollow feed-through for vacuum. Each of the at least two ejector units is configured as a part produced from one piece.

It is to be understood that embodiments of the present invention provide apparatus and a method for pumping a liquid, for example to recirculate liquid in a liquid storage tank by means of a gas lift pump. A perforated extension at the top of a gas lift allows the apparatus to be used in circumstances where the depth of liquid in the tank may vary over a wide range. Gases other than air may be used in the gas lift, so as to change the acidity and the concentrations of dissolved gases, particularly oxygen, in the liquid. The gas may be introduced into the gas lift through a whistle that generates intense sound waves and couples them into the liquid. These features when used in combination have particular application against invasive species in the ballast water of ocean-going tankers.

It is to be understood that embodiments of the present invention provide apparatus and a method for pumping a liquid, for example to recirculate liquid in a liquid storage tank by means of a gas lift pump. A perforated extension at the top of a gas lift allows the apparatus to be used in circumstances where the depth of liquid in the tank may vary over a wide range. Gases other than air may be used in the gas lift, so as to change the acidity and the concentrations of dissolved gases, particularly oxygen, in the liquid. The gas may be introduced into the gas lift through a whistle that generates intense sound waves and couples them into the liquid. These features when used in combination have particular application against invasive species in the ballast water of ocean-going tankers.

A multi-stage ejector is provided for producing vacuums in an industrial process and includes at least two ejector units axially arranged at a predetermined distance apart in an ejector housing. Each of the at least two ejector units includes at least two parallelly arranged hollow feed-throughs for compressed air, including inlet and outlet nozzles and at least one hollow feed-through for vacuum. Each of the at least two ejector units is configured as a part produced from one piece.

A multi-stage ejector is provided for producing vacuums in an industrial process and includes at least two ejector units axially arranged at a predetermined distance apart in an ejector housing. Each of the at least two ejector units includes at least two parallelly arranged hollow feed-throughs for compressed air, including inlet and outlet nozzles and at least one hollow feed-through for vacuum. Each of the at least two ejector units is configured as a part produced from one piece.