A subsea fluid pressure-increasing machine includes an elongated member that is rotatable about a longitudinal axis. The machine also may include a plurality of impellers each having a leading edge, a trailing edge, a suction side, and a chord line defined by a line between the leading and trailing edges. Each impeller is fixedly mounted to the member such that a chord angle defined by an angle between the chord line and the rotation direction is less than or equal to a stall angle at which a maximum force is exerted on a fluid in a direction primarily parallel to the longitudinal axis when the member is rotated in the rotation direction. At least some of the impellers comprise one or more features that effectively reduce a pressure peak or specific loading of the suction side such that the axial length of the impeller is configured to be reduced without exceeding a desired specific load.

A fluid vacuum pump includes a motor assembly including a single motor or multiple motors, where one motor may be configured for operation in a first medium and another motor may be configured for operation in a second medium; an impeller assembly including a single impeller, which may of a fixed or variable configuration, or multiple impellers, where one impeller may be configured for operation in a first medium and another impeller may be configured for operation in a second medium; and a linkage operatively connecting and adjustably transmitting power from the motor assembly to the impeller depending on the type of medium present.

A fluid vacuum pump includes a motor assembly including a single motor or multiple motors, where one motor may be configured for operation in a first medium and another motor may be configured for operation in a second medium; an impeller assembly including a single impeller, which may of a fixed or variable configuration, or multiple impellers, where one impeller may be configured for operation in a first medium and another impeller may be configured for operation in a second medium; and a linkage operatively connecting and adjustably transmitting power from the motor assembly to the impeller depending on the type of medium present.

A tapered rotary disc pump is disclosed, including a disc assembly with a first disc and a second disc arranged in parallel to define a chamber. Each disc has an inner surface with multiple vanes extending toward the chamber. The vane outer ends align with the disc periphery, while vane inner ends extend toward the disc center. At least one vane tapers from the outer end toward the inner end, and optionally from the inner surface toward the chamber, to reduce turbulence and increase pumping efficiency. Standoffs couple the discs together and may extend into the vanes to further minimize turbulence. The vane leading face may include convex and concave portions to enhance fluid flow. Alignment of opposing vanes and equal vane counts between discs provide balanced operation and improved handling of fragile, abrasive, or high-solids fluids.

An impeller pump has a housing having a suction chamber and a discharge chamber therein, a plurality of discs joined in spaced relationship and positioned within the housing, and a shaft extending through the housing and having an end adapted to be driven by motor so as to be rotated by the motor. The housing has a suction inlet that opens to the suction chamber and a discharge outlet that opens to the discharge chamber. The suction inlet has a pair of flow paths to the suction chamber. The plurality of discs includes a drive disc and a plurality of driven discs. The shaft is affixed to the drive disc such that the plurality of discs rotate within the housing.

A double-impeller leaf collector comprises a machine body, wherein the machine body is provided with a flow channel and a water absorption mechanism, the flow channel at least has a water inlet end and a water outlet end, and the water outlet end is provided with a garbage collection device; the water absorption mechanism comprises a driving device, and a lower impeller component and an upper impeller component arranged in the flow channel; wherein the driving device is connected with the lower impeller component and the upper impeller component through a transmission structure.