Module with integrated motor or generator and multi-stage device

Abstract

A coaxial pump or turbine module includes an integrated modular motor or generator that includes a magnetic structure containing radially or axially oriented permanent magnets and / or induction coils that are detachably secured to a rotor and a stator housing that is detachably secured to a module housing. A working fluid is axially directed through a flow path that is symmetrically distributed within an annular space formed between the module housing and the stator housing. The stator housing can be cooled by the working fluid or by a cooling fluid that flows between passages of the flow path. The flow path can extend over substantially the entire length and rear surface of the stator housing. Multiple modules can be combined into a multi-stage device in which rotor speeds are independently controlled by respective variable frequency drives. Embodiments include guide vanes and / or diffusers. The rotor can be secured to a rotating shaft or rotate about a fixed shaft.

Description

[0001] Related applications

[0002] This application claims the benefit of U.S. application No. 16 / 668,665, filed October 30, 2019, which is incorporated herein by reference for all purposes. Technical Field

[0003] The present invention relates to pumps and turbines, and more particularly to integrated sealless pumps and turbines. Background Art

[0004] Rotodynamic pumps and turbines are generally very similar in their physical design, so that the differences between pumps and turbines can sometimes be primarily a matter of use rather than construction. Therefore, unless the context requires otherwise, features of the invention and features of the prior art discussed herein with reference to turbines or pumps should be understood to refer equally to both.

[0005] In a traditional vane pump design, fluid flow and pressure are generated by a rotor, also called an "impeller," which rotates within a stationary pump housing. The torque required to drive the rotor is provided by an external motor and transmitted to the rotor, which rotates within the pump housing, via a rotating shaft. Similarly, in a traditional turbine design, fluid flow and pressure are applied to a rotor (also called a "runner" in the case of a turbine), causing it to rotate within a stationary turbine housing. The rotation and torque generated by the rotor are transmitted via a rotating shaft to an external generator.

[0006] One difficulty with these approaches is that they require dynamic seals to maintain a pressure boundary where the rotating shaft passes through the stationary pump or turbine housing. These seals are a source of leakage and other failure modes. Furthermore, a rigid baseplate is required to allow the pump and motor, or turbine and generator, to be mounted and aligned with each other to avoid vibration issues. Even with a rigid baseplate, nozzle loads on the pump or turbine can cause alignment issues between the motor or generator and the mechanical seal.

[0007] These difficulties can be avoided by designs that don't include shaft seals. For example, magnetically coupled transmissions don't require dynamic seals on the pump or turbine shaft because the motor or generator is magnetically coupled through the pump housing to an inner shaft supported by product-lubricated bearings within the housing. However, these designs still require careful alignment of the motor or generator with the rotor housing to connect the motor or generator to the rotor shaft as efficiently as possible. Furthermore, the components used for magnetic coupling add complexity and cost to the design.

[0008] Another approach to completely avoid dynamic shaft seals is to use an integral design where the motor or generator is included in the same housing as the rotor, such that no shaft seal is required. Some of these integral so-called "sealless motor" or "sealless generator" approaches use a radial field motor or generator design whereby the magnets are attached at or near the outer diameter of the rotor, the rotor is sealed within a thin walled "can", and an electromagnetic stator located outside of the sealed can surrounds the rotor. However, radial field designs necessarily require a significant increase in the diameter and length of the rotor housing. Another approach to an integral pump design is to implement an axial field motor or generator design whereby disk or "pancake" permanent magnets, brushless DC motors or generators are included within the rotor housing to provide high power density and result in the most compact and lightweight single stage pump or turbine unit possible.

[0009] However, the motor or generator coils of an integral sealless motor pump or sealless turbine generator can be difficult to cool. Typically, a special flow path must be provided within the housing to divert some of the working fluid through grooves in the immersed bearings and / or through another suitable path to absorb the heat generated from the motor or generator coils. The diverted working fluid is heated by convection from the stator walls and carries heat away from the stator to be expelled along with the non-diverted working fluid.

[0010] Unfortunately, as the diverted fluid passes through the channels adjacent the stator walls, through the hollow rotating shaft, through the bearings and / or through other suitable passages, a combination of the fluid heating and / or the pressure drop due to the transition from the discharge pressure to the suction pressure can result in a phase change occurring. As such, the fluid exposed to the vapor phase can cause the motor / generator to overheat and / or the bearings to fail. Furthermore, the requirement to divert some portion of the pump output or turbine input into the cooling flow necessarily reduces the efficiency of the pump or turbine.

[0011] Another disadvantage of pumps and turbines incorporating mechanical integral motors or generators prior to the present invention is that each pump or turbine design must require a corresponding integral motor or generator design. Thus, when a new pump or turbine design is introduced, a new motor or generator design must be introduced even if the torque and power requirements of the new motor or generator remain the same as the existing design. And, if multiple such pumps or turbines are required to be produced and / or supported simultaneously, separate production and / or inventory must be maintained for the different motor and generator designs.

[0012] In addition to the problems discussed above, another common problem encountered in the design of integral and non-integral pumps and turbines is how to scale up the capacity of an existing pump or turbine design to meet the requirements of a new application, which often requires redesigning the physical shape and size of the rotor, operating the rotor at higher speeds and / or adding additional rotors.

[0013] The total head generated by the pump is a function of the rotor diameter and its rotational speed, while the flow delivery for a given rotor diameter and speed is determined by the rotor width. For a given rotor design, the maximum rotor speed is limited by the amount of torque that the motor is capable of generating. The rotational speed is also limited by the frequency of the inverter used to drive the motor and the NPSH (Net Positive Suction Head) available at the rotor inlet.

[0014] Similarly, in the case of a turbine generator, under the control of the inverter or other control electronics associated with the generator, the generator applies a "load" to the turbine rotor according to the electromagnetic coupling between the rotating magnet and the generator coils, such that the maximum output of the generator is dependent on the maximum torque that the rotor is capable of delivering to the generator, which is dependent on the rotor diameter and width for a given fluid flow.

[0015] Therefore, one method of increasing the output of a pump or turbine is to increase the size of the rotor and the capacity of the motor or generator. However, the additional size and bulk that results from this method can be problematic.

[0016] When higher fluid pressure or generator output is required, the size and bulk of the pump or turbine rotor housing and other components can be reduced by using a small diameter rotor that runs at high speed. However, this method cannot be used for sealless motor and generator designs, as the rotor is also a component of the motor or generator. Specifically, in an axial sealless design, a smaller diameter rotor provides a smaller available disc area for mounting permanent magnets or induction magnets, limiting the torque generated by the motor, or the electrical power generated by the generator. Another limitation is that sealless motor designs (magnetic rotor and stator) capable of delivering a range of pressures and flows, and sealless generator designs capable of operating effectively over a range of pressures and flows, are relatively infeasible.

[0017] Therefore, for an axial motor sealless pump or turbine, the pump head or turbine output provided by the rotor can only be increased by increasing the diameter of the rotor. However, this method increases the bulk of the equipment, as it requires the use of larger and thicker rotor housings and other structural components to accommodate the larger components and higher fluid pressures.

[0018] Increasing output by expanding the number of rotors is also problematic for any pump or turbine design. In non-integrated multi-stage pumps or turbines, torque is provided by a single large motor through a common shaft to multiple rotors, or received by a single large generator from multiple rotors through a common shaft. This approach typically requires a large and heavy motor or generator, and, as the number of rotor stages increases, the diameter and length of the shaft must also be increased to accommodate the combined torque and weight of all the rotors.

[0019] Whether arranged horizontally or vertically, these long shafts with multiple rotor stages require larger bearings and increase the likelihood of bearing failure. In addition, the long shafts of multi-stage pumps cause various rotor dynamic problems related to shaft deflection and critical speed. For these and other reasons, each multi-stage pump design is only applicable to a specified maximum number of stages and cannot be easily scaled to accommodate different numbers of stages. In other words, scaling of existing designs typically requires a new pump or turbine design.

[0020] In addition, the multi-stage approach of elongated shafts requires all rotors to rotate at the same speed, which can limit the efficiency and / or NPSH (Net Positive Suction Head) performance of the design. In addition, failure of any stage in a multi-stage pump will result in immediate and complete failure of the entire pump or turbine.

[0021] Of course, one alternative to designing and implementing a multi-stage integrated or non-integrated pump or turbine is to simply interconnect multiple single-stage pumps or turbines in series and / or parallel. In the case of pumps, the output of each series pump becomes the input of the next pump, which further increases the pressure, while the outputs of pumps in a parallel configuration are combined to increase the output flow. In the case of turbines, fluid flows through the rotors in series or parallel, and the electrical output of the turbine generators is combined in series and / or parallel to produce a higher total output voltage and / or current.

[0022] However, this approach of combining multiple pumps or turbines into a multi-stage device requires the use of a large and complex fluid interconnect or manifold, consuming excessive space. In addition, as the number of pumps or turbines increases, the number of hoses and / or other fluid connections, and thus the risk of leaks and / or other failure modes, increases, resulting in reduced reliability of the equipment.

[0023] It has been proposed that a sealless disc motor pump can include more than one motor within a common housing. However, the fluid interconnect and motor / generator cooling requirements of a sealless disc motor design tend to limit this approach to at most only two stages.

[0024] For example, with reference to FIG. 1, one approach that has been proposed includes two centrifugal pump stages within a single sealless motor design 100, where each stage is driven by its own motor 102, and where the two stages are positioned back-to-back such that the two motors 102 are included within a common central space within a housing 112, such that they can be cooled by a common process flow path 104. In the example shown in FIG. 1, the two rotors 106 are facing in opposite directions, and each rotor includes permanent magnets 110 connected to its backside.

[0025] In some versions of this approach, the motors 102 are controlled by separate variable frequency drives ("VFDs") 114, and each of the rotors 106 rotates about a separate stationary shaft 108. In other versions, the motors share a common controller and / or shaft. By placing the two motors 102 within the same space, the cooling path 104 in this approach is only slightly more complex than in a single-stage integrated motor design, and the efficiency losses due to diverting flow into the cooling path are minimized. However, this approach is inherently limited to two stages, and there is no obvious way to extend this design beyond the two-stage limit.

[0026] Accordingly, what is needed is a compact and modular integrated "sealless" pump or sealless turbomachine design such that more than two pump or turbomachine modules (preferably up to any number) can be combined in series without bulky fluid interconnections in between. It is further preferred in embodiments that little or no process fluid is diverted from the main flow path for cooling the motors or generators within each module; the rotors in the modules rotate separately; and / or, the motors / generators in the modules are individually controllable. It is also desirable that the motors or generators that are integrated with the pump or turbomachine modules themselves should also be modular, such that the same motor or generator design can be incorporated into different pump or turbomachine designs. SUMMARY

[0027] The present invention is a "sealless" motor pump or sealless generator turbine configured as a highly compact module with a "concentric" flow design. The disclosed modular design enables more than two (preferably up to any large number) of pump or turbine modules to be combined in series with no bulky fluid interconnections between them and the rotors in each module individually rotating on their own shaft or other support. In embodiments, little or no process fluid is diverted from the main flow path for cooling the motor or generator within each module. In various embodiments, the rotors in the modular motor or generator are individually controllable. In embodiments, the motor or generator integrated with the pump or turbine module is itself modular, such that the same motor or generator design can be incorporated into different pump or turbine designs.

[0028] According to the present invention, the coil housing of the motor or generator, i.e., the stator housing, is concentrically surrounded by the outer housing of the module, i.e., the module housing, creating an annular space between them around the motor or generator coil and centered on the motor or generator's main axis. The working fluid enters the module axially through a proximal inlet port positioned substantially along the main axis and exits the module axially through a distal outlet port also positioned substantially along the main axis. Within the module, the working fluid flows symmetrically through the stator housing surrounding the motor or generator coil and through a plurality of substantially identical flow channels arranged symmetrically around the circumference of the stator housing, or through a single annular flow channel around the stator housing. This symmetric distribution of flow channels in the area surrounding the motor or generator coil provides a compact design in which the diameter of the module housing is only modestly larger than the diameter of the stator housing of the motor or generator.

[0029] In various embodiments adapted for use with relatively cool working fluids, the flow channels or single annular flow channel are in direct thermal contact with the housing of the motor or generator coil, thereby directly cooling the motor or generator coil. In some of these embodiments, more than 80% of the working fluid is in thermal contact with the motor or generator coil housing, and at least 20% of the motor or generator coil housing surface is in thermal contact with the working fluid. In various embodiments, more than 90% of the working fluid is in thermal contact with the motor or generator coil housing, and at least 50% of the motor or generator coil housing surface is in thermal contact with the working fluid.

[0030] In multi-channel embodiments adapted for use with hot working fluids, thermal insulation is provided between each of the plurality of substantially identical flow channels and the housing of the motor or generator coil. In some such embodiments, a cooling fluid is circulated in an annular space around the motor or generator coil housing such that the cooling fluid is in direct contact with the motor or generator coil housing, thereby cooling the motor or generator coil and protecting them from any residual heating of the hot working fluid.

[0031] In other embodiments, the hot working fluid flows through a single annular flow channel, thermal insulation is provided between the annular flow channel and the housing of the motor or generator coil, and in some such embodiments, a separate cooling fluid is circulated through cooling rings or cooling channels provided beneath the thermal insulation.

[0032] In embodiments, the concentric design of the present invention is implemented as a highly compact module that can be used individually or in series with multiple identical modules to form a multi-stage pump or turbine, where each stage includes a rotor and an associated motor or generator. This modular design allows the modules to be combined in any number of stages without adding additional complexity or complicating the design, operation, and maintenance of the device. In particular, because the rotor in each module is supported by a dedicated shaft or other support, a high number of stages does not cause any issues with respect to shaft size, shaft deflection, rotor dynamics, bearing loads, motor alignment, or alignment between stages.

[0033] In some embodiments, the rotor of each module is fixed to a rotating shaft. In other embodiments, the shaft of each module is fixed and the rotor rotates around the shaft, for example on bearings. For example, the shaft for each module can be inserted through the rotor hub and threaded into the module housing, which facilitates easy assembly and maintenance without the need for special tools.

[0034] Certain embodiments include modules having an inverted rotor / stator configuration whereby both the rotor and stator can rotate independently of one another in opposite directions. Some embodiments include separately rotating stators and / or diffusers. In some of these embodiments, the diffusers are implemented in a manner similar to that disclosed in patent application US 15 / 101,460, the entire contents of which are hereby incorporated by reference for all purposes.

[0035] In other embodiments, the disclosed modules do not include a shaft. Instead, the wear ring gap on the rotor front is used as the primary radial and axial bearing. By this means, torque is transmitted directly from the motor's electromagnet stator coil to the rotor or from the rotor to the motor's electromagnet stator coil, or electromagnetic energy is transmitted directly from the rotor to the generator, without the use of a rotating shaft.

[0036] In some embodiments, the disclosed pump or turbine modules include a radial motor or generator design, whereby a plurality of permanent magnets are attached at or near the periphery of the rotor, and the rotor is surrounded by an electromagnetic stator. In other embodiments, the disclosed modules include an axial "disc" or "pancake" motor or generator, whereby a plurality of permanent magnets are attached to the rear side of the rotor and, as the rotor rotates, the plurality of permanent magnets pass close to the electromagnetic coils of the axially adjacent stator. Some embodiments including permanent magnet motors or generators also include a variable speed drive that enables synchronous operating speeds of the module to exceed 3600 rpm.

[0037] Other embodiments include induction motors or generators using non-permanent magnets, such as "squirrel cage" rotor coils, where current is induced by stator electromagnets during pump or turbine operation.

[0038] In embodiments, a static sealing method is used to seal the motor or generator coils from the working fluid, which eliminates any need for dynamic mechanical seals and avoids alignment, leakage, and / or maintenance issues that would otherwise arise therefrom.

[0039] Various embodiments with centrifugal designs include radial flow rotors. Some of these embodiments include rotors with specific speeds up to 2,000 US units, 4000 US units, or even 5000 US units. Other embodiments include stages with radial flux motor or generator designs and higher specific speed mixed flow rotor designs.

[0040] In embodiments, the rotor is positioned axially and radially by product-lubricated bearings provided in each modular stage, which allows the bearings in each stage to be designed to handle only the load from that stage. This approach completely eliminates the risk of bearing overload due to the combined stage loads in a multi-stage arrangement and provides a more compact design because oversized bearings do not need to be used. In embodiments, using the working fluid as the bearing lubricant also eliminates the need for an external oil lubrication system and greatly simplifies the overall pump design. In embodiments, a combined radial and one-way thrust bearing is used instead of separate axial and radial bearings.

[0041] In various embodiments, the motors or generators in a multi-stage facility are individually controllable. Embodiments include multiple variable frequency drives, and in some of these embodiments, the motors or generators in each stage are independently controlled by dedicated VFDs. A key benefit of some of these embodiments is that the first stage can be run at a lower speed than the rest of the facility to accommodate low net positive suction head ("NPSH") and off-peak operating conditions. In some applications, varying the speed of only the final stage provides a useful method for precisely controlling output pressure and / or flow.

[0042] Providing a separate VFD driver for each stage can also serve as a failsafe redundancy, whereby if a stage fails, the rest will continue to operate and the device will continue to run. Continued operation after a pump or turbine stage failure can have a reduced head and flow, or the speed of the remaining stages can be increased to compensate for the loss of head and flow of the failed stage. This approach creates a failure scenario in which the pump or turbine can continue to operate with a reduced head and flow until the operator has time to safely shut down the system after becoming aware of the stage failure. Conversely, a failure of one stage in a conventional pump or turbine will result in a failure of the entire device, resulting in a complete loss of performance and a sudden, uncontrolled shutdown of the system. In various embodiments, the use of sensorless motors, along with appropriate VFDs, also reduces the instrumentation required on each stage.

[0043] In various embodiments, the motor or generator included in each module is modular in design, whereby a given motor or generator design can be incorporated into a plurality of different pump or turbine designs. In particular, the plurality of permanent magnets or other magnetic devices included in the motor or generator are included in a removable, modular magnetic structure that can be constrained axially and rotationally in coordination with the rotor of the pump or turbine. The axial and rotational constraints of the magnetic structure can be achieved by any means known in the art capable of constraining the magnetic structure axially and rotationally with respect to the rotor. Embodiments include a snap ring that axially constrains the magnetic structure and one or more pins that rotationally secure the magnetic structure to the rotor. Other embodiments include the magnetic structure being threadably attached to the rotor or attachment by screws or bolts, whereby the magnetic structure is constrained in both axial and rotational directions. Some of these embodiments also include an electrical port that can form a sealed passageway between the motor or generator housing and the pump or turbine housing to provide a path for electrical and / or control wires to extend between the stator and the external environment of the pump or turbine.

[0044] In embodiments, the magnetic structure and / or the stator portion of the motor or turbine containing the stator coils are modular and fully sealed, requiring only mechanical attachment to the housing of the pump or turbine proximate to one another. In various embodiments, the sealed modular magnetic structure and / or sealed modular stator assembly of the present invention can be implemented in different combinations, such that a new instance of the magnetic structure and / or stator assembly does not have to be configured each time a new pump or turbine module is designed.

[0045] A first general aspect of the present invention is a sealless pump or turbine module with an integrated motor or generator. The module includes an inlet located at a proximal end of the module, an outlet located at a distal end of the module, a module housing surrounding the module, a rotor suspended within the module housing, and a motor within the module housing configured to drive rotation of the rotor, or a generator within the module housing configured to be driven by rotation of the rotor, wherein the inlet is on a central axis of the module and the outlet is on the central axis of the module.

[0046] The motor or generator includes a stator located within a sealed stator housing, the stator including at least one electromagnet facing the rotor, the stator housing being removably secured axially, radially, and rotationally to the module housing, an electrical port formed in the stator housing and configured to form a seal with the module housing when the stator housing is secured to the module housing, the electrical port providing a sealed passage through which electrical conductors can be routed for interconnection between the at least one electromagnet and equipment external to the module housing, a plurality of magnetic devices assembled in a magnetic structure, the magnetic structure being removably constrained to be axially secured and rotationally coordinated with the rotor, the magnetic devices being configured by the magnetic structure to approach the at least one electromagnet as the rotor rotates, and flow paths distributed symmetrically about the stator housing.

[0047] Furthermore, the module is configured to direct the flow of the working fluid from the inlet through the flow path to the outlet such that the working fluid is symmetrically distributed about the stator housing as it flows within the flow path through the stator.

[0048] In an embodiment, the flow path is an annular flow path around the stator housing.

[0049] In any of the above embodiments, the flow path may include a plurality of flow channels symmetrically arranged around the stator housing.

[0050] In any of the above embodiments, the rotor may be suspended from a rotatable shaft and the rotor may be fixed to the shaft, or the rotor may be suspended from a fixed shaft and the rotor may be configured to rotate about the shaft.

[0051] In embodiments where the rotor is suspended from a stationary shaft and configured to rotate about the shaft, the rotor may be supported on the stationary shaft by a pair of bearings, one of which maintains the rotor's axial position while the other provides radial support for the rotor, or the rotor may be supported axially and radially on the stationary shaft by a single one-way thrust bearing. In any of these embodiments, the rotor may be supported on the stationary shaft by at least one bearing lubricated by a process fluid. In any of these embodiments, the stationary shaft may be secured to at least one of the stator housing and the module housing by a threaded connection.

[0052] In any of the above embodiments, the magnetic device may be a permanent magnet or a squirrel cage coil.

[0053] In any of the above embodiments, the flow path may extend over at least 50% of the surface of the stator housing and cause at least 90% of the working fluid flowing through the module from inlet to outlet to flow through the stator housing in direct thermal contact with the stator housing.

[0054] In any of the above embodiments, the module can be configured to require that all of the working fluid flowing from the inlet to the outlet flow through the flow path.

[0055] Any of the above embodiments may further include an insulating layer inserted between the flow path and the stator housing, and a cooling fluid path formed between the insulating layer and the stator housing, the cooling fluid path being thermally connected to the stator housing and configured to enable heat exchange between the stator housing and the cooling fluid flowing through the cooling fluid path.

[0056] In any of the above embodiments, the stator may be configured to rotate independently of the rotor and in a direction opposite to the direction of rotation of the rotor.

[0057] Any of the above embodiments may further include a diffuser that is coordinated with the rotor but driven by a separate diffuser motor and is thereby capable of rotating independently of the rotor.

[0058] In any of the above embodiments, the electromagnets of the stator may point toward the radial periphery of the rotor and the magnetic device may be fixed near the radial periphery of the rotor, or the electromagnets of the stator may point toward one side of the rotor and the magnetic device may be fixed to that side of the rotor or to a disk coaxial with and adjacent to that side of the rotor.

[0059] Furthermore, in any of the above embodiments, the magnetic structure may be sealed, thereby preventing the working fluid from reaching the magnetic device.

[0060] A second general aspect of the present invention is a multi-stage apparatus comprising a plurality of interconnected modules. Each module comprises an inlet at a proximal end of the module, the inlet being located on a central axis of the module; an outlet at a distal end of the module, the outlet being located on the central axis of the module; a module housing surrounding the module; and a rotor suspended within the module housing.

[0061] Each module also includes a motor within the module housing configured to drive rotation of a rotor, or a generator within the module housing configured to be driven by rotation of a rotor. The motor or generator includes a stator within a sealed stator housing, the stator including at least one electromagnet facing the rotor, the stator housing being axially, radially, and rotationally removably securable to the module housing; an electrical port formed in the stator housing and configured to form a seal with the module housing when the stator housing is secured to the module housing, the electrical port providing a sealed passageway through which an electrical conductor can be routed for interconnection between the at least one electromagnet and equipment external to the module housing; a plurality of magnetic devices assembled in a magnetic structure that is removably constrained to be axially fixed with and rotationally cooperative with the rotor, the magnetic devices being configured by the magnetic structure to be proximate the at least one electromagnet when the rotor is rotating; and flow paths symmetrically distributed about the stator housing.

[0062] Further, each module is configured to direct flow of working fluid from an inlet through the flow paths to an outlet, such that the working fluid is symmetrically distributed about the stator housing as it flows through the stator within the flow paths.

[0063] In embodiments of this general aspect, at least two of the motors or generators of the modules can be independently controlled in order to cause the respective rotors to rotate at different rates. And in some of these embodiments, the two independently controlled motors or generators are controlled by separate variable frequency drives.

[0064] In any of the above embodiments of this general aspect, the modules can be configured such that the device as a whole is able to continue to function as a pump or as a turbine despite failure of at least one of the modules included in the device.

[0065] Any of the above embodiments of this general aspect can also include control electronics that provide shared support to at least two of the modules.

[0066] In any of the above embodiments of this general aspect, the plurality of interconnected modules can include at least three interconnected modules.

[0067] And in any of the above embodiments of this general aspect, the magnetic structure in each module can be sealed so as to prevent working fluid from reaching the magnetic devices.

[0068] The features and advantages described herein are not all-inclusive and many additional features and advantages will be understood by persons of ordinary skill in the art upon examination of the drawings, the specification, and the claims. Additionally, it should be noted that the language used in the specification has been principally selected for readability and instructional purposes and not to limit the scope of the inventive subject matter. BRIEF DESCRIPTION OF DRAWINGS

[0069] Figure 1 is a cross-sectional view, drawn to scale, of a prior art two-stage integrated motor pump cooled by a dedicated cooling stream;

[0070] Figure 2A is a simplified cross-sectional view of a single-stage module of the present invention having a radial motor design;

[0071] Figure 2B is a cross-sectional view, drawn to scale, of a two-stage embodiment of the present invention having an axial motor design, viewed from the side;

[0072] Figure 2C is an exploded cutaway view, drawn to scale, of one of the rotor assemblies in the embodiment of Figure 2B

[0073] Figure 2D is a cutaway cross-sectional view, drawn to scale, of the rotor assembly of Figure 2C

[0074] Figure 2E is an exploded perspective cross-sectional view of the rotor assembly of Figure 2C

[0075] Figure 2F is a front perspective view, drawn to scale, of one of the stator assemblies in the embodiment similar to Figure 2B

[0076] Figure 2G is a side perspective view, drawn to scale, of the stator assembly of Figure 2F

[0077] Figure 2H is a simplified cutaway view of the embodiment including an annular flow path through the annular space;

[0078] Figure 2I is a cross-sectional view similar to Figure 2H but including additional concentric insulating layers and concentric cooling annular channels;

[0079] Figure 2J is a simplified cutaway view of the embodiment including multiple flow paths evenly distributed around and thermally isolated from the coil housing of the motor or generator;

[0080] Figure 3 ​​​​​is a scaled cross-sectional view of an embodiment similar to Figure 2, but including separate cooling flow paths (cooling paths not scaled);

[0081] Figure 4 is a scaled cross-sectional view of an embodiment similar to Figure 2, but including vanes in the process flow path;

[0082] Figure 5 is a scaled Figures 2C-2G is a perspective view of the housing of the pump of

[0083] Figure 6A is a scaled cross-sectional view from the side of a two-stage embodiment of the present invention having a modular motor design;

[0084] Figure 6B is a scaled Figure 6A is a scaled cross-sectional view from the side of one of the rotor and magnetic structure assemblies of the embodiment of

[0085] Figure 6C is a scaled exploded cross-sectional view from the side of the rotor and magnetic structure of Figure 6B

[0086] Figure 6D is a scaled exploded perspective view from the side and front of the rotor and magnetic structure of Figure 6C

[0087] Figure 6E is a scaled exploded perspective view from the side and rear of the rotor and magnetic structure of Figure 6D

[0088] Figure 6F is a scaled exploded perspective view from the side and front of one of the stator assemblies of Figure 6A

[0089] Figure 6G is a scaled exploded perspective view from the side and front of the stator assembly shown in Figure 6F

[0090] Figure 6H is a scaled exploded perspective view from the side and rear of the stator assembly of Figure 6G

[0091] Figure 6I is a scaled Figures 6A-6H is a perspective view of the housing of the pump of

[0092] Figure 7A is a perspective view of four modular pumps having a design similar to the​​​​​​Figures 6A-6H The pump is different, but combines Figures 6A-6H The same modular stator and magnetic structure design included in the pump module;

[0093] Figure 7B Drawn to scale Figure 7A a side, scaled, cross-sectional view of a single module of the pump; and

[0094] Figure 7C It is from Figure 7B A scaled side, exploded sectional view of a module. DETAILED DESCRIPTION

[0095] The present invention is a "seal-less" motor pump or seal-less turbine generator configured as a module with a "concentric" flow design. As an example, Figure 2A FIGURE 2 shows a pump embodiment 200 of the present invention. As can be seen in the figure, the housing 204 of the motor coil 212 (i.e., the stator housing 204) is surrounded by the housing 218 of the module, forming an annular space 202 therebetween. According to the present invention, the working fluid is distributed around the annular space 202, either between multiple flow channels or through a single annular flow channel. The distribution of the working fluid in the annular space 202 can be symmetrical about the stator housing 204. Figure 2A In the embodiment of FIG. 2 , the annular space 202 serves as an annular flow channel 202 through which the working fluid flows from the inlet 222 to the outlet 224 .

[0096] exist Figure 2A In the embodiment shown, the annular flow channel 202 is in direct thermal contact with the housing 204 of the motor coils 212. This configuration is suitable for applications where the working fluid is relatively cool. In the embodiment shown, the working fluid is directed by the rotor 206 to pass through the annular flow channel 202 over and around the module's motor coil housing 204, allowing the motor coils 212 to be cooled directly by the exhaust of the rotor 206, and eliminating the need for a separate, dedicated cooling fluid.

[0097] In an embodiment, the concentric design of the present invention is implemented as a standalone, highly compact module that can be used as Figure 2A Used alone as shown, or as Figure 2B As shown, multiple identical modules can be combined to form a multi-stage pump or turbine. This modular approach enables the design to be expanded to any number of stages without adding additional complexity or complication to the design, operation, and maintenance of the equipment. In particular, a high number of stages does not cause any problems with shaft size, shaft deflection, rotor dynamics, bearing loads, motor alignment, or alignment between stages.

[0098] More specifically, Figure 2BA two-stage pump embodiment 220 is shown in which the central axis of the motor 212 in each stage 200 is substantially collinear with the fixed shaft 208 about which the rotor 206 rotates, such that process fluid from the rotor 206 flows axially through the stator housing 204 through an annular flow passage 202 formed between the stator housing 204 and a pump housing 218 in each stage 200. For ease of illustration, although only two pump stages 200 are shown in Figure 2B It should be understood, however, that this embodiment is scalable to any number of pump stages 200.

[0099] In some multi-stage embodiments, the rotor 206 in each stage 200 is independently driven, such that the rotor speed of each stage 200 can be controlled individually. For example, a separate variable frequency drive ("VFD") 216 can be dedicated to control each stage 200 of the pump.

[0100] In embodiments of the Figure 2B In each stage 200 of the pump 220, a plurality of permanent magnets 210 are directly attached to the backside of the rotor 206 and are brought close to the electromagnetic coils 212 of the adjacent stator 212 as the rotor 206 rotates, in other embodiments, the rotor 206 comprises an induction motor utilizing non-permanent magnets 210, such as "squirrel cage" rotor coils in which an electric current is induced by the stator electromagnets 212 during pump or turbine operation. In this way, torque is directly transferred from the electromagnetic motor coils 212 to the rotor 206 without the use of a rotating shaft, or electromagnetic energy is transferred from the rotor to a generator coil. In embodiments, the motor coils 212 are sealed from the working fluid using a static sealing method (not shown), which eliminates any need for dynamic mechanical seals and avoids the alignment, leakage, and / or maintenance issues that such seals can cause.

[0101] In embodiments of the Figure 2B In each stage, the axial and radial positioning of the rotor 206 is provided by product lubricated bearings 214. By using a separate bearing 214 for each rotor stage 200, the bearing 214 in each stage 200 can be designed to only bear the load from that stage, and the risk of bearing overload from combined stage loads in a multi-stage arrangement 220 is completely eliminated. In embodiments, the working fluid is used as a lubricant for the bearings 214, eliminating the need for an external oil lubrication system and greatly simplifying the design and maintenance of the overall pump.

[0102] Figures 2C-2E are similar to those described above with respect to Figure 2BFigure 1 is a front perspective view of one embodiment of a stator assembly of a pump or turbine module. Figure 2 is a front perspective view of one embodiment of a rotor assembly of a pump or turbine module. Figure 3 is a side exploded view, exploded perspective view, and exploded perspective cutaway view of one embodiment of a rotor assembly in the embodiment of Figures 1 and 2. In the illustrated embodiment, the magnet 210 is included in a magnet structure 252, which also includes a magnet "back iron" 236 and a magnet structure cover plate 238. The assembled magnet structure 252 is mounted within an annular cavity 240 provided in the rotor 206.

[0103] Figure 2F and Figure 2G are Figures 2B-2E Figure 1 is a front perspective view of one embodiment of a stator assembly of a pump or turbine module. Figure 2 is a front perspective view of one embodiment of a rotor assembly of a pump or turbine module. Figure 3 is a side exploded view, exploded perspective view, and exploded perspective cutaway view of one embodiment of a rotor assembly in the embodiment of Figures 1 and 2. In the illustrated embodiment, the magnet 210 is included in a magnet structure 252, which also includes a magnet "back iron" 236 and a magnet structure cover plate 238. The assembled magnet structure 252 is mounted within an annular cavity 240 provided in the rotor 206.

[0104] In some embodiments, such as Figure 2A , the rotor 206 in each stage is fixed to the rotating shaft 208. In other embodiments, such as Figure 2B , the shaft 208 in each stage is inserted through a rotor hub of the rotor 206 and fixed to the motor or generator coil housing 204, and the rotor 206 rotates about the shaft 208 (e.g., on bearings 214). This approach facilitates easy assembly and maintenance without the need for special tools. In similar embodiments, the shaft 208 is threaded or otherwise supported by the pump or turbine module housing 218, or by any combination of the pump or turbine module housing 218 and the motor or generator stator housing 204.

[0105] Certain embodiments include modules 200 having an inverted rotor / stator configuration, whereby both the rotor 206 and the stator 212 can rotate independently of each other in opposite directions. Some embodiments include multiple rotors 206 fixed to a common stationary or rotating shaft 208, in combination with separately rotating stators and / or diffusers. In some of these embodiments, the diffuser is implemented in a manner similar to that disclosed in patent application US 15 / 101,460, the entire contents of which are incorporated herein by reference and for all purposes.

[0106] In further embodiments, no shaft 208 is provided, and instead, a wear ring gap on the front of each rotor 206 is used as the primary radial and axial bearing. By this means, torque is transmitted directly from or to the motor's electromagnet stator coils 212 to the rotor, or electromagnetic energy is transmitted from the rotor 206 to the generator's coils 212, without the use of a rotating shaft.

[0107] Figure 2His a simplified cross-sectional view of an embodiment having an annular flow passage, similar to Figure 2A , where the cross section is taken through the pump motor coil 212 perpendicular to the main axis of the motor.

[0108] Figures 2A-2H The embodiment is suitable for relatively cool working fluids, wherein the annular flow channel 202 brings the working fluid into direct thermal contact with the motor or generator coil housing 212, thereby cooling the motor or generator coils. Figures 2A-2H In various embodiments, more than 80% of the working fluid is in thermal contact with the motor or generator coil housing 212, and at least 20% of the motor or generator coil housing 212 is in thermal contact with the annular flow path 202. In various embodiments, more than 90% of the working fluid is in thermal contact with the motor or generator coil housing 204, and at least 50% of the motor or generator coil housing surface 204 is in thermal contact with the annular flow path 202.

[0109] refer to Figure 2I In some embodiments where high temperature working fluids are anticipated, the annular flow passage 202 and the housing 204 of the motor or generator coil 212 may be modified by including an additional concentric insulation layer 228 between the annular flow passage 202 and the housing 204 of the motor or generator coil 212. Figure 2H In some of these embodiments, a concentric cooling annular channel 234 is further formed between the thermal insulation layer 228 and the coil housing 204 , through which a cooling fluid such as water or cooling oil can circulate from the inlet 230 to the outlet 232 .

[0110] refer to Figure 2J In other embodiments, the working fluid is distributed among a plurality of substantially identical flow channels 226 arranged symmetrically around the circumference of the stator housing 204 within the annular space 202. Figure 2J In the embodiment of FIG. 1 , the flow channel 226 is formed by the module housing wall 218. Similar to FIG. Figure 2I , Figure 2J The embodiment also includes a concentric annular insulation layer 228 and a concentric cooling annular channel 234.

[0111] refer to Figure 3 In an embodiment, a small amount of the working fluid is diverted through a separate cooling path 300 where the working fluid is cooled and then circulated through concentric annular cooling passages 234 in thermal contact with the stator housing 204 to cool the motor coils 212. In a similar embodiment, a separate cooling fluid, such as water or cooling oil, is circulated through the cooling path 300 without diverting any working fluid.

[0112] In various embodiments, the fluid cooling of the motor or generator coil 212 allows the system to operate with high temperature working fluids and also enables the system to provide higher performance limits and greater power density throughout the pump or turbine, even if the temperature of the working fluid is not increased.

[0113] Referring Figure 4 The embodiment includes a flow vane 400, which, if the flow passage is annular, is in the annular flow space 202; or elsewhere in the flow path. In the illustrated embodiment, the flow vane 400 controls the flow of process fluid in a portion of the concentric flow path at the end of the motor or generator coil 212, where the flow path turns radially inward toward the central axis of the module. The flow vane 400 divides the flow path into multiple separate but symmetrical paths until the fluid flow reaches the central axis and flows axially out through the outlet 224 and into the next stage 200. In embodiments, the flow vane 400 directs the process fluid within the flow path in close proximity to the motor or generator stator housing 204.

[0114] The flow vane 400 can also provide a housing wall that can be used to guide power cables from the sealed motor or generator 212, through the fluid passage 202, and out of the pump housing 218 to the variable frequency controller 216. In embodiments, the flow vane 400 also serves as a fin, providing additional convective surface area to cool the motor or generator coil 212, and / or providing space for integrated cooling channels 300 that are connected to an external source of cooling fluid.

[0115] Figure 5 is Figures 2C-2G an external perspective view of a pump of

[0116] Referring Figure 6A In various embodiments 610, the motor or generator is of a modular design, whereby a given motor or generator design can be incorporated into a number of different pump or turbine designs. In the example of FIG. 6, a number of magnetic devices 210 that cooperate with the rotor of the motor are incorporated in a removable magnetic structure 600 that can be secured to and removed from the rotor 206 of the pump 200. The connection of the magnet structure 600 to the rotor can be achieved in any manner known in the art, wherein the magnetic structure 600 can be axially and rotationally constrained relative to the rotor. Some embodiments include a threaded attachment of the magnetic structure to the rotor, which axially and rotationally constrains the magnetic structure. In the embodiment of FIG. 6, the magnetic structure 600 is attached to the rotor 206 by bolts 602, which axially and rotationally constrain the magnetic structure 600 to the rotor 206.

[0117] Figure 6A Embodiments of the pump 200 also include electrical ports 608 (see Figure 6H), which provides a sealed passageway from the void 250 within the stator housing 204 that houses the stator coils 212, through the rear flange 248 of the stator housing 204, providing a path for the electrical and / or control wires to extend between the stator coils 212 and the external environment of the pump 200. As can be seen in the figure, the stator housing 204 includes a flange 248 that is bolted and sealed to the rear end thereof. This flange 248 includes a female receptacle 604 into which the electrical port 608 is inserted and forms an O-ring seal therewith.

[0118] In embodiments, the magnetic structure 600 and / or the stator portion 204 of a motor or turbine containing stator coils is modular and fully sealed, requiring only mechanical attachment in proximity to one another to the housing 200 of a pump or turbine. In various embodiments, the sealed modular magnetic structure 600 and / or sealed modular stator assembly 204 of the present invention can be implemented in different combinations, such that it is not necessary to configure a new instance of the magnetic structure 600 and / or stator assembly 204 each time a new pump or turbine module is designed.

[0119] Figure 6B is Figure 6A an enlarged sectional view of one of the rotor 206 and magnetic structure 600 when assembled. Figure 6C is Figure 6B a cross-sectional exploded view of the rotor 206 and magnetic structure 600. Figure 6D and Figure 6E are Figure 6B front and rear exploded perspective views of the rotor 206 and magnetic structure 600 of Figure 6F is an enlarged exploded perspective view from the front of one of the stator assemblies of Figure 6A showing the relationship to the rear flange 248 of the pump housing. As can be seen, the guide vanes 400 that are located in the outlet flow path of the process fluid are affixed to the rear flange 248, with the rear plate 244 of the module having been removed to expose the interior. Figure 6G is the same as Figure 6F except that the rear plate 244 has been welded in place, completing the sealed stator assembly. Figure 6H is an enlarged exploded perspective view from the rear of the stator assembly of Figure 6G As can be clearly seen in the figure, the electrical port 608 that serves as a passageway for the stator coil leads 606. Figure 6I is Figure 6A a perspective view of the fully assembled pump 610 of

[0120] Figure 7A is a perspective view of a pump design 700 of four modules, which is quite different from the pump of Figures 6A-6H Figure 7B is Figure 7A a cross-sectional view of a single module 708 of the pump of​Figure 7C is Figure 7B an exploded cross-sectional view of the modular 708 of the pump 700. As can be seen in the figure, the diffuser 702 includes in the design shown, and the back flange 248, the pump rotor 206, the stator housing 204, and the pump housing 218 are all quite different from the design shown in Figures 6A-6H . However, Figures 7A-7C the pump 700 includes substantially the same modular motor components as included in Figures 6A-6H . The only small difference is that in the embodiment shown, a snap ring 704 is used to axially constrain the magnetic structure 600, and a pin 706 is used to rotationally constrain the magnetic structure 600. However, it is clear that a bolt could be used to constrain the magnetic structure, as Figures 6A-6H shown, with only minor modifications to the design.

[0121] In Figure 2B , Figure 4 , Figure 6A and Figure 6H , only two pump modules 200 are shown, while the pump 700 of Figure 7 includes five modules. In general, it can be readily seen that in embodiments, any number of the disclosed pump or turbine stages 200 can be combined in series, without adding additional complexity or complication to the design, operation, and maintenance of the pump or turbine 200. In particular, higher numbers of stages according to the disclosed design do not cause any problems with shaft size, shaft deflection, rotor dynamics, bearing loads, motor alignment, or alignment between stages 200.

[0122] Certain embodiments include at least some drive electronics that are shared between more than one stage. For example, in some embodiments, AC power is converted to DC power by a common set of large electronics, and then the DC power is distributed as needed to individual pump or turbine stages. Other embodiments include multiple variable frequency drives ("VFDs") 216, and in some of these embodiments, the motor or generator coils 212 in each stage 200 of the pump or turbine are independently controlled by a dedicated VFD 216 or other controller. One of the key benefits in some such embodiments is that the first stage can be run at a lower speed than the rest of the pump, in order to accommodate low net positive suction head ("NPSH") and off-peak operating conditions. In some applications, simply varying the speed of the last stage provides a useful method for precisely controlling the output pressure and / or flow.

[0123] Providing a separate VFD driver 216 for each stage 200 can also serve as a failsafe redundancy, whereby if one stage fails, the rest will continue to operate and the pump will continue to run. Continued operation after a pump stage failure can have a reduced head and flow, or the speed of the remaining pump stages can be increased to compensate for the loss of head and flow of the failed pump stage. This approach creates a failure scenario in which the pump can continue to operate with a reduced head and flow until the operator has time to safely shut down the system after becoming aware of the pump stage failure. In contrast, failure of one stage in a conventional pump or turbomachine typically results in failure of the entire pump or turbomachine, resulting in a complete loss of performance and sudden, uncontrolled shutdown of the system.

[0124] In Figure 2A In embodiments, the motor is a radial motor that includes permanent magnets mounted around the outer periphery of the rotor, while other embodiments shown in the figures include a disc or "pancake" type rotor 206 that incorporates permanent magnets 210 positioned on the back side of the back surface of the rotor 206. In other embodiments, an induction motor can be used. Some embodiments include a variable speed drive that enables the synchronous operating speed of the pump stage 200 to rise above 3600 rpm.

[0125] In the embodiments shown in the figures, the pump stage 200 is a centrifugal design with a radial flow rotor 206. Some such embodiments include a rotor with a specific speed of up to about 2,000 US units, in some embodiments, the rotor has a speed of up to 4000 US units, or even 5000 US units. Other embodiments include a pump stage 200 with a radial flux rotor design.

[0126] In the embodiments shown in the figures, a combined radial and one-way thrust bearing 214 is used in place of separate axial and radial bearings. The shown embodiments include a stationary shaft 208 that is inserted through a rotor hub of the rotor 206 and screwed into the pump stage housing 218, which facilitates easy assembly and maintenance without special tools. In the shown embodiments, the use of a sensorless motor, along with an appropriate VFD driver 216, also reduces any requirement for instrumentation on each stage 200.

[0127] Certain embodiments of the present invention include modular stages 200 with an inverted rotor / stator configuration, whereby both the rotor and stator can rotate independently of one another in opposite directions. Also, some embodiments include a stator and / or diffuser that is separately rotatable, e.g., with a separate motor driving the rotor and diffuser. In some such embodiments, the diffuser is implemented in a manner similar to that disclosed in patent application US 15 / 101,460.

[0128] As is well known in the art, vane pumps and turbines are often very similar in their physical design, such that the differences between a pump and a turbine are sometimes primarily a matter of usage rather than structure. Thus, while the embodiments shown in the drawings are pumps, features of the present application discussed herein with reference to turbines or pumps should be understood to equally apply to both, unless the context otherwise requires.

[0129] The foregoing description of embodiments of the application has been presented for the purposes of illustration and description. However, the pages of the submission herein, each of which is herewith incorporated by reference in its entirety, and all contents thereon, whether or not in the form of application programs or located on the pages, are to be considered as being part of this application for all purposes. This description is not exhaustive or limited to the precise forms disclosed. Many modifications and variations are possible in light of this disclosure.

[0130] While this application has been presented in a limited number of forms, the scope of the present application is not limited to these forms but can be variously changed and modified without departing from the spirit thereof. The disclosure presented herein does not explicitly disclose all possible combinations of features falling within the scope of the present application. The features disclosed herein for various embodiments can generally be interchanged and combined in any combination that is not self-contradictory without departing from the scope of the present application. In particular, the limitations presented in the following dependent claims can be combined in any number and in any order with their respective independent claims, unless the dependent claims are logically incompatible with each other, without departing from the scope of the present disclosure.

Claims

1. A module with an integrated motor or generator, said module being a sealless pump or turbine and comprising: an inlet located at a proximal end of the module, the inlet being on a central axis of the module; an outlet, the outlet being located at a distal end of the module and on a central axis of the module; a module housing surrounding the module; a rotor suspended within the module housing; a motor or a generator, the motor being located within the module housing and being configured to drive the rotation of the rotor, or the generator being located within the module housing and being configured to be driven by the rotation of the rotor, the motor or the generator comprising: a stator positioned within a sealed stator housing, the stator being axially offset relative to the rotor and including at least one electromagnet with its axial proximal end facing the rotor, the stator housing being removably axially, radially, and rotationally securable to the module housing; an electrical port formed in the stator housing and configured to form a seal with the module housing when the stator housing is secured to the module housing, the electrical port providing a sealed passage through which an electrical conductor can be routed for interconnection between at least one of the electromagnets and equipment external to the module housing; a plurality of magnetic devices assembled in a magnetic structure removably constrained to be axially fixed and rotationally coordinated with the rotor, the magnetic devices being configured by the magnetic structure to be axially proximate to at least one of the electromagnets when the rotor rotates; and a flow path symmetrically distributed about the stator housing; a hollow protrusion structure and a socket, the hollow protrusion structure surrounding the central axis of the module and extending from one of the proximal end and the distal end of the module, the socket surrounding the central axis of the module and formed at the other of the proximal end and the distal end of the module, wherein the working fluid flowing from the inlet, flowing through the flow path, and flowing out of the outlet flows through the hollow protrusion structure and the socket; The sealless pump or turbine module is capable of forming a first direct connection at its proximal end to the distal end of a preceding identical sealless pump or turbine module, and is capable of forming a second direct connection at its distal end to the proximal end of a following identical sealless pump or turbine module, wherein the first and second direct connections comprise inserting a hollow protrusion of the module into a socket of one of the preceding and following modules and receiving the hollow protrusion of the other of the preceding and following modules in the socket of the module, The working fluid is distributed symmetrically about the stator housing when flowing through the stator in the flow path.

2. The module according to claim 1, wherein The flow path is an annular flow path around the stator housing.

3. The module according to claim 1, wherein The flow path includes a plurality of flow channels arranged symmetrically about the stator housing.

4. The module according to claim 1, wherein The rotor is suspended by a rotatable shaft, and the rotor is fixed to the shaft.

5. The module according to claim 1, wherein The rotor is suspended by a fixed shaft, and the rotor is configured to rotate about the shaft.

6. The module according to claim 5, wherein The rotor is supported on the fixed shaft by a pair of bearings, one of which maintains the axial position of the rotor and the other of which provides radial support for the rotor.

7. The module according to claim 5, wherein The rotor is supported axially and radially on the stationary shaft by a combined radial and one-way thrust bearing.

8. The module according to claim 5, wherein The rotor is axially and radially supported on the stationary shaft by at least one bearing lubricated by the working fluid.

9. The module according to claim 5, wherein: The fixed shaft is fixed to the stator housing by threaded attachment.

10. The module according to claim 1, wherein The magnetic device is a permanent magnet.

11. The module according to claim 1, wherein The magnetic device is a squirrel cage coil.

12. The module according to claim 1, wherein The flow path extends over at least 50% of the surface of the stator housing and causes at least 90% of the working fluid flowing through the module from the inlet to the outlet to flow in direct thermal contact with the stator housing.

13. The module according to claim 1, wherein The module is configured to require that all of the working fluid flowing from the inlet to the outlet flow through the flow path.

14. The module according to claim 1, further comprising: a heat insulating layer interposed between the flow path and the stator housing; as well as A cooling fluid path is formed between the thermal insulation layer and the stator housing, the cooling fluid path being in thermal communication with the stator housing and configured to enable heat exchange between the stator housing and a cooling fluid flowing through the cooling fluid path.

15. The module according to claim 1, wherein The stator is configured to rotate independently of the rotor and in a direction opposite to a rotation direction of the rotor.

16. The module of claim 1 further comprising a diffuser in conjunction with the rotor but driven by a separate diffuser motor and thereby rotatable independently of the rotor.

17. The module according to claim 1, wherein The electromagnet of the stator is directed toward the radial periphery of the rotor, and the magnetic device is fixed near the radial periphery of the rotor.

18. The module according to claim 1, wherein The electromagnet of the stator is directed toward one side of the rotor, and the magnetic device is fixed to the one side of the rotor or to a disk coaxial with and adjacent to the one side of the rotor.

19. The module according to claim 1, wherein The magnetic structure is sealed, thereby preventing the working fluid from reaching the magnetic device.

20. A multi-stage apparatus comprising a plurality of interconnected modules, each module being a module according to any one of claims 1 to 19.

21. The apparatus according to claim 20, wherein At least two of the motors or generators can be independently controlled to rotate the respective rotors at different rates.

22. The apparatus according to claim 21, wherein The two independently controlled motors or generators are controlled by separate variable frequency drives.

23. The apparatus of claim 20, wherein: The modules are configured such that upon failure of at least one of the modules included in the device, the device as a whole can continue to function as a seal-less pump or as a turbine.

24. The apparatus of claim 20, further comprising control electronics that provide shared support to at least two of the modules.

25. The apparatus of claim 20, wherein The plurality of interconnected modules includes at least three interconnected modules.

26. The apparatus of claim 20, wherein: The magnetic structure in each of the modules is sealed, thereby preventing the working fluid from reaching the magnetic device.

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