A vertical pump features a shaft having an end with an impeller arranged thereon and rotates about an axis; a stationary bushing having an axial bushing surface, a radial bushing surface, and a central bushing bore; and a thrust balance drum that includes a central balancing drum bore to receive the shaft, that couples to the shaft so as to rotate about the axis, that includes an axial balance drum surface and a radial balance drum surface, and that is arranged in the central bushing bore of the stationary bushing with the axial balance drum surface positioned with respect to the axial bushing surface to define an axial clearance, and with the radial balance drum surface positioned with respect to the radial bushing surface to define a radial clearance. In operation, the thrust balance drum balances thrust loads produced by the impeller.

A fluid rotor and a fluid stator. The fluid stator surrounds the fluid rotor. The fluid stator has an intake end and a discharge end. The fluid stator is shaped to be inserted into a wellbore. A shaft passes through a rotational axis of the fluid rotor. The shaft is attached to the fluid rotor to rotate in union with the fluid rotor. The shaft defines a central fluid passage that extends from the intake end of the fluid rotor to the discharge end of the fluid rotor. A balance piston surrounds the shaft. The balance piston extends from an outer surface of the shaft to an inner surface of the fluid stator. The balance piston is positioned at the intake end.

A first fluid rotor that has a first fluid intake end and a first fluid discharge end. The first fluid rotor includes a shaft and an impeller. A second fluid rotor that has a second fluid intake end and a second fluid discharge end. The second fluid rotor is rotatably coupled to the first fluid rotor to rotate in unison with the first fluid rotor along a shared rotational axis. The first fluid intake end and the second fluid intake end are facing opposite directions. The second fluid rotor includes a second shaft and a second impeller. A first fluid stator surrounds the first fluid rotor. The first fluid stator is aligned along the rotational axis. The first fluid rotor and the first fluid stator form a first fluid stage. A second fluid stator surrounds the second fluid rotor. The second fluid stator is aligned along the rotational axis. The second fluid stator and the second fluid rotor form a second fluid stage. A flow crossover sub is positioned between the first fluid stage and the second fluid stage. The flow crossover sub defines flow passages that fluidically connect the first fluid stage and the second fluid stage. An outer housing surrounds the first fluid stator, the second fluid stator, and the flow crossover sub.

A self-adjusting drum system for use with a pump or similar rotating machinery includes a balancing drum mounted on a central shaft for joint rotation therewith. The shaft extends along an axial direction and the balancing drum has an outer surface. A fixed, stationary structure surrounding the balancing drum is provided. The stationary structure has an inner surface arranged so as to face the outer surface of the balancing drum, and an annular gap is provided therebetween. A bush element is arranged in the annular gap so as to leave clearance with respect to the inner and/or outer surfaces. A fixing component is further provided for fixing the bush element to the stationary structure so as to lock the bush element against movement along the axial direction and allow it to freely move along a radial direction, inside the annular gap.

A vertical pump includes: a rotary shaft; multi-stage impellers; a casing accommodating the multi-stage impellers; a mechanical seal provided in a penetration part of the casing for the rotary shaft; a balance sleeve, the balance sleeve being positioned between a final stage impeller of the multi-stage impellers and the mechanical seal in the penetration part for the rotary shaft; an intermediate chamber provided between the rotary shaft and the casing and provided on an opposite side of the multi-stage impellers across the balance sleeve in an axial direction of the rotary shaft, the intermediate chamber communicating with an intermediate stage impeller among the multi-stage impellers; a low pressure chamber provided between the rotary shaft and the casing, the low pressure chamber communicating with a low pressure side compared to the intermediate chamber; and a partition wall part dividing the intermediate chamber and the low pressure chamber.

A turbo compressor is provided that may include an impeller housing having an impeller accommodation space, an inlet formed at a first side of the impeller accommodation space, and an outlet formed at a second side of the impeller accommodation space that communicates with the inlet; an impeller accommodated in the impeller accommodation space of the impeller housing, rotated together with a rotary shaft by being coupled to the rotary shaft, and configured to centrifugally-compress a fluid suctioned through the inlet of the impeller housing and discharge the compressed fluid outside of the impeller housing through the outlet; a back pressure space formed between a rear surface of the impeller and the impeller housing; a back pressure passage connected between the outlet of the impeller housing and the back pressure space; and a back pressure control valve installed between the back pressure passage and the back pressure space, and configured to selectively open and close a region therebetween.

A centrifugal pump assembly has an electric drive motor (2) and at least one impeller (10; 10), which is movable in an axial direction (X) between at least two functional positions. In one functional position a flow path through the impeller (10; 10) is essentially closed and in another functional position the flow path through the impeller (10; 10) is opened. The impeller (10; 10) in a first functional position is held by a magnetic force (F.sub.M) or a spring force and in a second functional position is held by a hydraulic force (F.sub.H) produced by a delivered fluid. An impeller is provided for the centrifugal pump assembly.

A pump assembly (2) includes an electric drive motor (14) and with at least one impeller (18) which is driven by the motor. The impeller is movable in an axial direction (X) between at least one first and one second position. The impeller in the first axial position is situated in a first flow path through the pump assembly and delivers a fluid through this first flow path. The impeller in the second position is situated in a second flow path through the pump assembly and delivers a fluid through this second flow path. The pump assembly (2) is configured such that a movement of the impeller (18), between the first and the second position at least in one direction, is effected by a hydraulic force which acts on the impeller (18) and is produced by the delivered fluid. A heating installation is provided with such a pump assembly.

A thrust balancing mechanism for balancing axial loads on a rotor thrust bearing 3 is described. The mechanism comprises a piston arrangement 6 axially mounted on a stationary structure 2, about a center axis arranged, in use, in coaxial alignment with a rotating shaft 1 carrying the rotor thrust bearing 3. A hydrodynamic thrust bearing 8 is mounted, in use, between the piston 6 and the rotor thrust bearing 3. The piston 6 is pressurized so as to impart to the rotor thrust bearing 3, via the hydrodynamic thrust bearing 8, an axial load which counters an axial load imparted to the rotor thrust bearing 3 by the rotating shaft 1.

A centrifugal pump includes a radial impeller surrounded by a housing. The housing has a channel associated with a front side space between a cover of the impeller and the casing. Flow is led through the channel from a pressure region of the pump to a radial gap at a suction region of the pump. The flow in the channel reduces angular momentum and results in an increase in pressure in the front side space which acts of in the cover side of the impeller to offset axial force from a rear side of the impeller.