The present application relates to a sealing soft water recovery apparatus for a vacuum pump in a vacuum pressure swing adsorption oxygen generation system, including a water tank, a wet Roots vacuum pump, a steam-water separator, and a collecting sink which are sequentially connected, where the collecting sink is connected to the water tank by a delivery tube provided with a delivery pump; and the water tank is connected to the wet Roots vacuum pump by a water inlet tube provided with a solenoid valve for controlling the opening and closing of a water channel. The present application has the effects of recovering sealing soft water and saving resources.

A double-flow pump with a housing which has at least one inlet, at least one outlet and a conveyor housing with two single-part or multi-part conveyor units which convey a conveying medium from the inlet in opposite directions to the outlet, the conveyor units have shaft ends which are mounted in bearings, the bearings are each arranged in a bearing housing, wherein the shaft ends are detachably connected to the conveying units.

Method for controlling one or more vacuum generators (1) and thereby the vacuum in a vacuum sewage system, in particular controlling one or more liquid ring screw pumps in such system, including beyond the generator/s (1) one or more tubular collectors or suction pipelines (2) connected to the vacuum generator and one or more toilets, urinals, grey water sinks etc (3, 4), connected to the suction pipeline through branch pipelines (6). The rotational speed of the vacuum generator (1) is controlled on the basis of the set vacuum requirement.

Method for controlling one or more vacuum generators (1) and thereby the vacuum in a vacuum sewage system, in particular controlling one or more liquid ring screw pumps in such system, including beyond the generator/s (1) one or more tubular collectors or suction pipelines (2) connected to the vacuum generator and one or more toilets, urinals, grey water sinks etc (3, 4), connected to the suction pipeline through branch pipelines (6). The rotational speed of the vacuum generator (1) is controlled on the basis of the set vacuum requirement.

A control system comprising: a liquid ring pump; a motor configured to drive the liquid ring pump; and a controller configured to: determine an electrical current within the motor; determine a speed of the motor; calculate a value of a function, the function being a function of the determined electrical current within the motor and the determined speed of the motor; and output one or more control signals based on the calculated value of the function.

A control system comprising: a liquid ring pump; a motor configured to drive the liquid ring pump; and a controller configured to: determine an electrical current within the motor; determine a speed of the motor; calculate a value of a function, the function being a function of the determined electrical current within the motor and the determined speed of the motor; and output one or more control signals based on the calculated value of the function.

A liquid ring pump includes a planar port plate having first and second planar walls, a sidewall which defines a shaft receiving aperture, an inlet, and an outlet. An opening is formed in the port plate and includes an open end that extends through the sidewall and an open face that extends through the first planar wall. A rotor shaft is rotatable about a central axis and is positioned such that a portion of the rotor shaft extends into the shaft receiving aperture. An aperture is formed in the port plate and positioned substantially opposite the opening. The opening, a space defined between the rotor shaft and the sidewall, and the aperture, cooperate to define a channel that extends between a first side of the shaft receiving aperture and a second side of the shaft receiving aperture, wherein the channel is formed entirely coplanar with the port plate.

A liquid ring pump is provided. The liquid ring pump is designed to reduce the overall envelop of the ring pump. The liquid ring pump includes a housing and an impeller. The housing defines an impeller cavity. The impeller cavity has an inlet port and a discharge port. The impeller is positioned within the impeller cavity for rotation about a central rotational axis. The impeller includes a central hub defining a conical outer surface and a plurality of angularly spaced apart main vanes extending radially outward from the conical outer surface relative to the central rotational axis. The inlet and discharge ports may be located on a same side of the impeller housing.

A liquid ring pump includes a port plate coupled to a pump head. The port plate has an opening with a first end at a first section and a second end at a second section. The first section opens through a portion of a surface forming a first face of the port plate. The second section opens at the second end into a shaft receiving aperture of the port plate. The first and second sections are continuous. The first section is angularly between the closing edge of a port plate outlet and leading edge of a port plate inlet. A length measured from the first section to the inlet's leading edge is less than a length measured from the first section to the outlet's leading edge. The first section does not open into the outlet or inlet.

A fluid ring compressor comprises a first single-acting compression stage having a first impeller eccentrically mounted in a housing and a second single-acting compression stage having a second impeller eccentrically mounted in a housing. The first compression stage and the second compression stage are separated from one another by a sealing gap. The sealing gap is arranged between a suction section of the first compression stage and a suction section of the second compression stage.