Patent Description:
An impeller is a rotating component of a rotating machine like, for example, a pump or a compressor, whether this machine is for single or multi-phase fluid. A motor source drives the impeller(s), and the impellers transfer energy to the fluid being pumped. In an example pump, the impellers might be stacked up with an interim diffusor stage in between. The diffusor stage has an increasing flow area and transforms the fluid kinetic energy into fluid pressure. For a contra-rotating compressor or pump, diffusor stages might not be needed. In some contra-rotating embodiments, the opposite rotation of adjacent impeller stages might transform portions of the kinetic energy into next-level increased pressure energy. In order to raise performance, i.e. large capacity, high pressure increase, and good efficiency, the operating envelope of a rotating machine might be optimized. Such optimization might comprise minimizing pressure loads, avoiding undesirable flow regime.

Conventional electrically powered rotating fluid processing machines such as pumps and compressors mount the impellers on the outer surface of a long central shaft that is rotated by an electric motor. The electric motor is therefore longitudinally offset from the impellers by an axial distance, and the overall length of the combined motor and pump or compressor section is likewise quite long. In many applications, such as subsea fluid processing, the size, weight and length of the entire system including the shaft and electric motor are all important factors for the overall system deployment cost as well as for the locations where the fluid processing equipment can be deployed. Furthermore, due to the shaft occupying the central portion of the impeller section, conventional fluid processing machines may not accommodate pipeline pigging equipment for performing various maintenance operations. In cases where pigging equipment is accommodated, a separate bypass pipeline section has to be installed (or the pump is installed on a bypass section), which further limits deployment flexibility and increases cost.

<CIT> describes an integrated pumping system for use in environments, such as subterranean environments, to move a desired fluid from one location to another. The integrated pumping system comprises a number of stages in sequence along a common axis and each stage has a pump axially adjacent to a motor,. In one embodiment the motor is provided by a stator with a plurality of electromagnets at an axial face of the stator. The pump comprises an impeller and has permanent magnets on an axial face which faces the electromagnets. The pump is driven by sequential energising of the electromagnets. A controller may be utilized to individually control the pumps and motors.

<CIT> describes a compressor with impeller assemblies which are driven in alternate directions around a central axis. An individual impeller assembly has impeller blades projecting from a rotor which incorporates permanent magnets. A respective stator coil inside the rotor generates a rotating magnetic field which electromagnetically engages the rotor and drives its rotation.

<CIT> which was not published before the priority date of the present application describes a pump with a series of impellers which rotate in alternate directions around a common axis. The impellers all have a permanent magnet at its outer diameter and each one is driven by an individual stator.

According to one aspect of this invention, a fluid processing machine comprises: a first stator configured to generate a rotating electromagnetic field; and at least one first rotor section internal to the first stator that includes at least one set of axially spaced impellers each having permanent magnets located on the outer diameter thereof. The first stator is configured to electromagnetically engage with the at least one first rotor section inducing its rotation about a central axis in a first rotational direction thereby causing the impeller(s) to impart kinetic energy on the fluid being processed. The machine further includes at least one second stator configured to generate a rotating magnetic field and electromagnetically engage with at least one second rotor section rotatable about the central axis in a second rotational direction opposite to the first rotational direction, and the at least one second rotor section comprises at least one set of axially spaced second impellers having permanent magnets located on the internal diameter thereof. The second rotor section is internal to the first stator and the second stator is internal to the second rotor section. The impellers of the at least one first rotor section are interleaved with the impellers of the at least one second rotor section.

According to some embodiments, the at least one first rotor section comprises one rotor section and further rotor sections displaced therefrom and from each other along the central axis. Each of this plurality of rotor sections comprises at least one set of axially spaced impellers having permanent magnets thereon, and each are configured to electromagnetically engage with the stator and be induced by the stator to rotate about the central axis in the first rotational direction. According to some embodiments, each of the rotor sections is configured to engage at least one thrust bearing to at least partially counteract axial force imparted on the impellers during operation. In some cases each rotor section has its own dedicated thrust bearing that counteracts all of the axial force imparted by the impellers of that rotor section. In other examples some of the imparted axial force is passed through structures and counteracted by another thrust bearing. Some forms of the machine may possibly include static diffusors configured to convert at least some of the kinetic energy imparted on the fluid into increased fluid pressure.

According to some embodiments, an outer casing surrounds the first stator and the first rotor section(s). The first stator might be canned within a housing that is filled with a liquid. A first rotor section might have a sleeve on its outside diameter configured to contain the permanent magnets. The first stator might be made up of a plurality of stator sections connected to each other. A passive or active cooling system utilizing the cool surrounding seawater can be included.

The permanent magnets might be rare earth magnets such as neodymium magnets and samarium-cobalt magnets. According to some embodiments, the fluid processing machine is a gas compressor, wet gas compressor, single phase compressor, multiphase compressor, gas pump, liquid pump, multiphase pump, single phase pump, or an electric submersible pump. For example, the machine might be an electric submersible pump configured for deployment on a seafloor or in a wellbore.

According to some embodiments, the machine can be configured for deployment in a horizontal orientation in-line with a fluid flow line. According to some embodiments, the machine has an area which is unoccupied within the machine and the machine is configured to allow for passage of an oilfield service equipment (e.g. a pipeline pig) through the area.

According to some embodiments, a system is described that transports fluid produced from at least one well using a plurality of the previously described fluid processing machines. According to some embodiments, the well(s) are on a seabed and the system is a subsea system for lifting the produced fluid to a surface facility. One or more heaters can be configured to heat the produced fluid in one or more locations thereby reducing viscosity of the fluid, and resulting in reduced fluid flow friction. According to some embodiments, the plurality of machines might be deployed in locations such as: in-well, integrated into a Christmas tree, along a flowline between tree and subsea manifold, or along a flowline between subsea manifold and said surface facility. According to some embodiments, the system might include a first variable speed drive (VSD) that might be located topside in the surface facility, and a second VSD located subsea. In such cases, the subsea fluid processing machines might be driven using a combination of the first and second VSDs. Alternatively, multiple VSD's, all subsea, can be used for the purpose of start-up and/or speed control.

According to a second aspect of the invention, a system with heaters as defined in claim <NUM> is provided.

The subject disclosure is further described in the detailed description which follows, with reference to the drawings in which like reference numerals represent similar parts throughout the several views of the drawings, and wherein:.

The particulars shown herein are by way of example and for purposes of illustrative discussion of the subject disclosure only. In this regard, no attempt is made to show structural details in more detail than is necessary for the fundamental understanding of the present disclosure, the description taken with the drawings making apparent to those skilled in the art how forms of the present disclosure may be embodied in practice. As used herein the term "impellers" refers to any impeller blade, regardless of whether the processed fluid is air, another gas, a mixture of gas and liquid, or a liquid. Further, like reference numbers and designations in the various drawings indicate like elements.

According to the second aspect of the invention, a distributed pumping and pipeline heating system is used to optimize production. According to some embodiments, the power infrastructure can be shared by the pumps and heating system. In order to lift hydrocarbons from the seafloor to the surface facilities several pumps and heating systems might be used together. The heating system might be used to reduce frictional losses due to lowering fluid viscosity. Multiple, distributed fluid pumps can be used to increase differential pressure incrementally. Furthermore, a distributed pumping system may be desirable due to constrained sea floor terrain and topography.

The disclosed fluid processing machine, according to some embodiments, when compared to a conventional subsea pumping system is compact, lightweight, and more efficiently and easily fitted to subsea piping. According to some embodiments, the disclosed fluid processing machine is able to accommodate a flowline pig or other equipment to service the well. According to some other embodiments, a flowline pig might be accommodated by using a bypass, in a manner such as used with conventional pumping systems. According to some embodiments, the disclosed fluid processing machine can be integrated part of a subsea christmas tree, and/or located within a wellbore as an electrical submersible pump (ESP).

<FIG> is a diagram illustrating a subsea environment in which disclosed fluid processing machine(s) can be deployed, according to some embodiments. On sea floor <NUM> a subsea manifold <NUM> is shown which is downstream of several wells being used in this example to produce hydrocarbon-bearing fluid from a subterranean rock formation. In this simple example, there are four wells <NUM>, <NUM>, <NUM> and <NUM> that are producing fluid from rock formation <NUM>. At the sea floor <NUM>, wells <NUM>, <NUM>, <NUM> and <NUM> are connected to christmas trees <NUM>, <NUM>, <NUM> and <NUM>, respectively. According to some embodiments, some or all of the wells contain one or more electric submersible pump (ESP) to aid in producing the produced fluid. In <FIG>, ESPs <NUM> and <NUM> are visible within wells <NUM> and <NUM>, respectively. According to some embodiments, fluid processing machines like pump units, such as described in further detail herein, are used as ESPs <NUM> and/or <NUM>. Furthermore, such pump units might also be integrated into one or more of the christmas trees <NUM>, <NUM>, <NUM> and <NUM>. By being compact, lightweight and easily pipe-fittable, the disclosed fluid processing machines can be integrated in christmas tree configurations where it would have been impractical to deploy conventional subsea pumps.

According to some embodiments, multiple pumps of the disclosure and flowline heating systems are implemented in a subsea infrastructure, making production more efficient and/or increasing overall oil recovery. Unlike some conventional subsea pumps, the pumps according to some embodiments of the disclosure can be mounted horizontally in the same direction as the flowline. The pump of the disclosure can also be fitted to a flowline using horizontal clamping techniques or other common techniques such as welding.

Flowlines (or pipes) <NUM>, <NUM>, <NUM> and <NUM> carry produced fluid from wells <NUM>, <NUM>, <NUM> and <NUM>, respectively, to manifold <NUM>. Flowline <NUM> then carries the produced fluid from manifold <NUM> to a surface platform <NUM> along sea floor <NUM> through seawater <NUM>. In other cases, other surface facility types can be substituted for platform <NUM> such as a floating production, storage and offloading unit (FPSO), or a shore-based facility. In cases of relatively long tie back distances from the wells <NUM>, <NUM>, <NUM> and <NUM> to manifold <NUM>, several pumps may be applied for each well, and possibly several sections that are heated. In the example of <FIG>, pump units of the disclosure <NUM>, <NUM>, <NUM> and <NUM>, and flowline heating units <NUM>, <NUM>, <NUM> and <NUM> are installed on flowlines <NUM>, <NUM>, <NUM> and <NUM>, respectively. In this example, each flowline has one pump unit and one heating unit. Similarly, fluid flow within flowline <NUM> is aided by compact pump unit <NUM> and heating unit <NUM>. Note that manifold <NUM> can also include a pump unit, according to some embodiments. In other examples other numbers of pump and heating units can be used. In some cases, for example heating may not be provided. According to some embodiments, completely insulated piping and/or continuous heated piping (not sections) may be applied. According to some embodiments, the pumping system and heating system may use a common power and control system that is described further with respect to <FIG>, infra. Although four wells are shown in the example of <FIG>, other numbers of wells could be connected to manifold <NUM>. Additionally, other manifolds that are connected to other wells can be provided and connected to platform <NUM> using separate flow lines or through further manifolds.

The distributed system of pumps according to the disclosure (and heating) may provide advantages over conventional subsea systems including: reducing topside and subsea infrastructure, and reducing tie-back cable cost. By supplying power and control to multiple pumps and heating units using a single subsea umbilical cable, large cost savings on cable and installation can be achieved.

Not shown are one or more umbilical cables run from surface platform <NUM> to supply electric power for the pump units and heating units. According to some embodiments, the one or more umbilicals can also be used to supply barrier and other fluids, and control and data lines for various subsea equipment. Further detail of electrical power supply and control is provided with respect to <FIG>, infra.

Although many embodiments described herein refer to pump units, according to some embodiments, the combined motor and impeller sections can be configured for other subsea fluid processes, such as a compressor and/or a subsea separator. In embodiments described herein, it is understood that references to subsea pumps and pump units can alternatively refer to subsea compressors. Furthermore, references herein to subsea pumps and subsea compressors should be understood to refer equally to subsea pumps and compressors for single phase liquids, single phase gases, or multiphase fluids.

Although the well <NUM>, <NUM>, <NUM> and <NUM> have been described as being used to produce hydrocarbon-bearing fluid (such as oil, gas, condensate or combinations thereof) from a subterranean rock formation, according to some embodiments the pump units of the disclosure can be used in connection with other types of wells including: water injection well, water disposal well, and gas injection well.

According to some embodiments, the pump unit and the associated pipelines and equipment are deployed in a top-side surface location. For example, in <FIG>, wells <NUM>, <NUM>, <NUM> and <NUM> might be surface and/or transition zone wells, and one or more of the flowlines, pump units and heating units might be surface-deployed. According to some other embodiments, the pumped fluid can be a liquid, such as water (including seawater), a gas, or a multiphase mixture of liquid and gas phases.

<FIG> is a schematic diagram illustrating aspects of electrical power supply to a number of pump units of the disclosure and other subsea equipment, according to some embodiments. Note that in this example, surface platform <NUM> is shown as a vessel such as an FPSO. In the surface facility (vessel <NUM>), are a surface variable speed drive (VSD) and a step up transformer <NUM>. The electrical power is transmitted via a single power cable <NUM> that may include, for example, three conductors transmitting <NUM>-phase power. The cable <NUM> is connected to a subsea multi-winding transformer <NUM> that can provide several different step down voltages with galvanic isolation. Using a topside VSD <NUM> avoids any inrush into step down transformer <NUM> and also into any of the subsea VSDs, which may have built-in transformers. The topside VSD <NUM> might also be used to regulate the pipeline heating. An advantage of using a multi-winding transformer <NUM> is galvanic isolation of the various subsea circuits. Additionally, a separate winding in transformer <NUM> can be provided for pipeline heater <NUM>, which is providing heating for flowline <NUM>. Providing a separate winding for the heater <NUM> may be desirable since the heater may use quite different voltage and current values than the pump units. Another separate winding of transformer <NUM> is provided for pump unit <NUM>, which includes both an electric motor and pump, as shown symbolically. According to some embodiments, the transformer <NUM> switching unit <NUM> may be located in a subsea station such as at the location of manifold <NUM> (shown in <FIG>). In such cases the power supply lines from switch unit <NUM> to pump unit <NUM> and heater <NUM> can be routed back up along the flowline <NUM>. Note that the "+n" notation in <FIG> means that there can be one or more additional similar elements, so there can be multiple additional pump units and/or heaters, according to the needs of the particular application. For example, in some cases multiple pump units may more efficiently move the produced fluid through the flowline <NUM> to the vessel or platform <NUM>, when compared with conventional systems that employ a single, higher capacity pump located at the subsea manifold. Furthermore, a distributed system may be less prone to catastrophic risk from pump failure than a conventional system. According to some embodiments, the power for heater <NUM> (and/or compact pump <NUM>) could be provided from a separate power cable coming from the vessel (or platform) <NUM>. An advantage of routing the power from subsea location, such as depicted in <FIG>, however, is that it saves hanger space, and/or slip rings in the case of swivel on an FPSO, for example. Christmas trees <NUM>, <NUM>, and <NUM> are shown for wells <NUM>, <NUM> and <NUM>, respectively. Compact pump units <NUM>, <NUM> and <NUM> are shown within christmas trees <NUM>, <NUM>, and <NUM>, respectively. ESPs <NUM>, <NUM> and <NUM>, which use pump units of the disclosure, are shown within wells <NUM>, <NUM> and <NUM>, respectively.

According to some embodiments, a dedicated VSD can be provided locally for each well, such as the case for VSD <NUM> driving compact pump unit <NUM> in christmas tree <NUM> and ESP <NUM>. Although two pump units are being run in parallel by a single VSD <NUM>, both pumps are used to produce the same fluid flow. In other cases, a single VSD can be used to drive pumps for multiple wells, such as the case for VSD <NUM> using switches <NUM> for driving pumps <NUM>, <NUM>, <NUM> and <NUM> in two different wells <NUM> and <NUM>. Note that sharing a single VSD among multiple pumps may be especially desirable in cases where all the pumps can be driven at the same speed. Sharing a single VSD among multiple wells beneficially reduces the number of subsea VSDs for a given number of wells. According to some embodiments, the subsea VSD can be used for starting the pump and then bypassed. This way, several trees and downhole-pumps can be started with a single subsea VSD. After the bypass is engaged, the pumps will run at same frequency as the other subsea pump units (e.g. pump unit <NUM>), all being driven by topside VSD <NUM>. According to some embodiments, the individual pump unit speeds can be tailored to some degree by varying the pole pair numbers of the electric motor. According to some embodiments, the process can be reversed so that the bypass is removed and speed control is engaged using the subsea VSDs. In general, the number of VSDs used will depend on the complexity of the system and how difficult the wells are to operate. Note that while <FIG> shows the electrical power lines and various VSDs, the various control lines for transmitting control signals are not shown, for simplicity.

As mentioned, supra, in a conventional system a single subsea booster pump is often deployed at the seabed (often called mudline pump) typically at a manifold. Thus, the conventional subsea pump may have to cope with the flow from several production wells. This increases the power rating by a typical factor of <NUM>-<NUM> over that of an in-well pump (e.g. an ESP). Thus, implementing a distributed system using several pump units of the disclosure such as shown in <FIG> and <FIG> can provide significant decreases in cost and/or risk when compared with a conventional system that uses single topside or a single subsea VSD for a single large pump located at the manifold.

<FIG> is a cross section view of a pump unit for multiphase fluids, embodying some features of this disclosure. Pump <NUM> is configured as a multiphase pump that might be used in various subsea and surface applications. According to some embodiments, pump <NUM> can be used for one or more of the pump units shown and described in <FIG> and <FIG> including pump units <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM>. In example pump <NUM>, the electric motor and pump sections are integrated in compact fashion, rather than being separated by a drive shaft and mechanical coupling(s) as in conventional systems. The pump is enclosed in a casing <NUM> that according to some embodiments includes a plurality of cooling fins <NUM>. The stator <NUM> surrounds the rotor, which is made up of a stack of impeller stages in impeller/diffuser stack <NUM>. The stator <NUM>, with stator windings <NUM>, generates a rotating electromagnetic field that induces a rotating movement to the "rotor" or rotating impellers that have permanent magnets mounted thereon. The rotating impellers rotate about a central axis <NUM> of pump <NUM>. According to some embodiments, the stator is "canned" with volume <NUM> filled with a liquid such as an insulating oil or barrier fluid. Penetrator <NUM> is included for a three-phase electrical power cable to pass though the casing <NUM>. According to some embodiments other pass-through technology could be used for passing power through the casing <NUM>.

The impeller/diffuser stack <NUM> includes alternating rotating impellers (such as on impeller assembly <NUM>) and stationary diffusers (such as on diffuser assembly <NUM>). Each impeller increases the kinetic energy and pressure of the multiphase fluid being processed while each diffuser converts the kinetic energy into a further fluid pressure increase. According to some embodiments, the impellers and diffusers are stacked upon one another as will be described in further detail, infra. Pump <NUM> has an inlet <NUM> and an outlet <NUM>. Fluid is drawn into the inlet <NUM> and then through passages or conduits <NUM>, as shown by the dotted arrows. After flowing through the impeller/diffuser stack <NUM> the fluid exits via conduits <NUM> to outlet <NUM>. Note that by integrating the motor and pump in the example shown in <FIG> there is large central area <NUM> that is not occupied by a drive shaft as in many conventional pump designs. According to some embodiments, the central area <NUM> can be used to pass a pipeline pig, or other servicing tool, through the pump <NUM> when the pump is not running. According to some embodiments, a check valve <NUM> is shown that might be in a closed position, such as depicted in <FIG>, when the pump <NUM> is operating. This is because during pump operation the fluid pressure at the outlet <NUM> might be higher than at the inlet <NUM>. When the pump is not operating, however, the inlet pressure might be higher than, or nearly equal to, the outlet pressure, and the check valve moves to the open position. Alternatively, the check valve <NUM> can be operated by an actuator (not shown). An actuated valve may also be desirable in some applications, such as: (<NUM>) a means of control where pumps are run at a constant speed (rpm); and (<NUM>) where difficult start-up conditions exist.

In the open position the check valve <NUM> and central area <NUM> allow, for example, for a pipeline pig to pass through the pump <NUM>.

According to some embodiments, the stator section might be cooled passively by the surrounding seawater and cooling fins <NUM>. According to some other embodiments, the stator might include active cooling wherein a special or single impeller (not shown) might achieve circulation. Alternatively, at least one magnet on at least one rotor section can induce a magnet on the other side of the stator skin (i.e. within volume <NUM>), in a magnet coupling principle, and set up cooling for an element, by a small impeller on the stator side for example. In some embodiments, cooling might be made by cooling fluid such as monoethylene glycol (MEG) or a dielectric fluid.

<FIG> is a cross section view illustrating further detail of a portion of the impeller/diffuser stack of a pump unit for multiphase fluids,. As can be seen, the diffuser assembly <NUM> includes a hub body <NUM> and a diffuser element <NUM> that is shaped so as to convert the fluid velocity into pressure. Rotor body <NUM> is a metallic rotor piece, part of which is formed into impeller element <NUM>. The rotating impeller assembly <NUM> includes permanent magnets <NUM> around the outer surface of rotor body <NUM>. Impeller element <NUM> is shaped to increase kinetic energy and pressure of the fluid. According to some embodiments, multiple impeller elements <NUM> are included in rotor body <NUM>. According to some embodiments, permanent magnets <NUM> are attached to rotor body <NUM> using glue or some other adhesive, or welding. According to some other embodiments, magnets <NUM> are inserted into slots formed into rotor body <NUM>. Between each of the stages might be interstage seals, such as interstage seals <NUM>, <NUM> and <NUM>. The interstage seals provide a degree of pressure isolation between the successive stages as well as limit the radial pressure exerted between the rotating impellers and the stator.

<FIG> is a cross section view illustrating further detail of a portion of the impeller/diffuser stack of a pump unit for multiphase fluids. Visible are two impeller/diffusers pairs <NUM> and <NUM> that are "stacked" upon one another. This stacking arrangement of impellers and diffusers may provide ease of assembly and other benefits. Also visible in <FIG> is magnet containment member <NUM> that surrounds, contains and protects permanent magnets <NUM>.

<FIG> are cross section views of a diffuser assembly and an impeller assembly, respectively, of a pump unit for multiphase fluids. In <FIG>, axial or thrust bearing <NUM> and two radial bearings <NUM> and <NUM> are visible. The bearings might be lubricated by, for example and without limitation, (regenerated) monoethylene glycol (MEG), or other fluids coming from the barrier side for internal cleanliness and bearing operation. In embodiments wherein the fluid processing machine is a water injection pump, the water itself might be the lubricant material. Alternatively, thrust or other bearings might contain diamond coating, ceramics, etc., and/or might be lubricated by the process fluid. By providing a thrust bearing <NUM> between each impeller and diffuser assembly, smaller thrust forces can be handled incrementally, and the use of larger thrust disks might be avoided. According to some embodiments, a conventional thrust disk might be provided to carry the axial load of some or all of the impeller stages. Additionally, a conventional separate barrier fluid circuit might be provided to supply lubrication to some or all of the bearings. In embodiments, and protection means might be provided to the axial and radial bearings. According to some embodiments, other types of bearing technology might be implemented. Examples include, not limitatively: magnetic bearings, chemical injection bearings, and diamond coated bearing surfaces. In one example, process fluid lubrication of the bearings is supplemented by injecting chemicals in certain locations in order to improve the environment for the bearings and other mechanical components with small clearances. Also visible in <FIG> is groove <NUM> for the interstage seal <NUM> shown in <FIG>, supra.

Referring to <FIG>, magnet containment member <NUM> might be transparent to electrical fields whilst maintaining the permanent magnets <NUM> contained due to centrifugal forces. Member <NUM> might be made of woven carbon fibers, Kevlar, glass in an epoxy resin, or a thermoplastic material. The rotor body <NUM> might comprise wear resistant coatings in locations where radial bearings <NUM> and <NUM> and/or thrust bearing <NUM> interfaces with rotor body <NUM>.

Part of rotor body <NUM> might be formed into sleeve portion <NUM>. Sleeve portion <NUM> supports (or contains) the permanent magnets <NUM> and reduces or avoids impeller losses and/or flow regime interference from impeller stage to impeller stage. Impeller induced swirling on the impeller outside diameter may be reduced, creating increased performance. Other phenomena in relation to flow-induced interference (from one impeller stage to the next impeller stage, for example) may hence also be reduced. According to some embodiments, the blade shape of impeller element <NUM> is cylindrical (i.e. the shape does not change along the radial direction). In some embodiments, however, the impeller element <NUM> is non-cylindrical in that its shape changes in the radial direction. Note that in general, impeller elements <NUM> can be any style or shape.

<FIG> is a cross section view of a pump unit for single phase fluids, embodying features of the disclosure. Pump <NUM> is configured as a single phase pump that might be used in various subsea and surface applications. Pump <NUM> can be used for one or more of the pump units shown and described in <FIG> and <FIG>, including pump units <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM>. As in pump <NUM> shown in <FIG>, supra, pump <NUM> integrates an electric motor and pump sections in compact fashion, rather than being separated by a drive shaft as in conventional systems. The pump is enclosed in a casing <NUM> that according to some embodiments includes a plurality of cooling fins <NUM>. The stator <NUM> surrounds the rotor, which is made up of a stack of impeller stages in impeller/diffuser stack <NUM>. The stator <NUM>, with stator windings <NUM>, generates a rotating electromagnetic field that induces a rotating movement to the "rotor" or rotating impellers that have a permanent magnet mounted thereon. The rotating impellers rotate about a central axis <NUM> of pump <NUM>. According to some embodiments, the stator is "canned" with volume <NUM> filled with a liquid such as an insulating oil or barrier fluid.

The impeller/diffuser stack <NUM> includes alternating rotating impellers (such as on impeller assembly <NUM>) and stationary diffusers (such as on diffuser assembly <NUM>). Each impeller increases the kinetic energy and pressure of the single phase fluid being processed, while each diffuser converts the kinetic energy into a further fluid pressure increase. According to some embodiments, the impellers and diffusers might be stacked upon on another as will be described in further detail, infra. Pump <NUM> has an inlet <NUM> and an outlet <NUM>. Fluid is drawn into the inlet <NUM> and then through passages or conduits <NUM>, as shown by the dotted arrows. After flowing through the impeller/diffuser stack <NUM>, the fluid exits via conduits <NUM> to outlet <NUM>. Note that by integrating the motor and pump in the example shown in <FIG> there is large central area <NUM> that is not occupied by a drive shaft as in many conventional pump designs. According to some embodiments, the central area <NUM> can be used to pass a servicing equipment such as, but not limited to, a pipeline pig through the pump <NUM> when the pump is not running. Shown is a check valve <NUM> that might be in a closed position such as depicted in <FIG> when the pump <NUM> is operating. When the pump is not operating, the check valve <NUM> moves to the open position, allowing passage of a pipeline pig through pump <NUM>.

The stator section might be passively cooled by the surrounding seawater and cooling fins <NUM>. According to some other embodiments, the stator might be actively cooled such as described with respect to <FIG>, supra.

<FIG> is cross section view illustrating further detail of a portion of the impeller/diffuser stack of a pump unit for single phase fluids. As can be seen, the diffuser assembly <NUM> includes a hub body <NUM> and a diffuser element <NUM> that is shaped so as to convert the fluid velocity into pressure. The rotating impeller assembly <NUM> includes permanent magnets <NUM> around its outer surface and rotor body <NUM>. Magnets <NUM> can be adhered or inserted into slots as discussed supra with respect to magnets <NUM>. Impeller element <NUM> might be shaped to increase kinetic energy and pressure of the fluid. As shown, multiple impeller elements <NUM> are included in rotor body <NUM>. Between each of the stages might be interstage seals, such as interstage seals <NUM>, <NUM> and <NUM>. The interstage seals provide a degree of pressure isolation between the successive stages as well as limit the radial pressure exerted between the rotating impellers and the stator.

<FIG> is a cross section view illustrating further detail of a portion of the impeller/diffuser stack of a compact pump unit for single phase fluids, according to some embodiments of the disclosure. Visible are two impeller/diffusers pairs <NUM> and <NUM> that are "stacked" upon one another. This stacking arrangement of impellers and diffusers may provide ease of assembly and other benefits. Also visible in <FIG> is magnet containment member <NUM> that surrounds, contains and protects permanent magnets <NUM>. According to some embodiments, permanent magnets <NUM> might change thickness along the axial direction as shown, which allows more radial space for the impellers and diffusers while maintaining overall compactness of the pump unit. According to some other embodiments, the magnets <NUM> might be constant thickness along the axial direction such as magnets <NUM> shown in <FIG> and <FIG>, supra.

<FIG> are cross section views of a diffuser assembly and an impeller assembly, respectively, of a pump unit for single phase fluids. In <FIG>, axial or thrust bearing <NUM> and two radial bearings <NUM> and <NUM> are visible. The bearings might be lubricated, for example and without limitation, by (regenerated) monoethylene glycol (MEG), or other fluids coming from the barrier side for internal cleanliness and bearing operation. In embodiments wherein the fluid processing machine is a water injection pump, the water itself might be the lubricant material. By providing a thrust bearing <NUM> between each impeller and diffuser assembly, smaller thrust forces are handled incrementally, and the use of larger thrust disks might be avoided. Alternate bearing arrangements and technology can be employed, such as discussed supra with respect to <FIG>. Also visible in <FIG> is groove <NUM> for the interstage seal <NUM> shown in <FIG>, supra.

Referring to <FIG>, magnet containment member <NUM> might be transparent to electrical fields whilst maintaining the permanent magnets <NUM> contained due to centrifugal forces. Member <NUM> might be made of woven carbon fibers, Kevlar, glass in an epoxy resin, or a thermoplastic material.

<FIG> is a cross section view illustrating aspects of a contra-rotating compressor, in accordance with the first aspect of the present invention. Contra-rotating compressor <NUM> is configured as a wet gas compressor that might be used in various subsea and surface applications. According to some embodiments, compressor <NUM> can be used in place of one or more of the compact pump units shown in <FIG> and <FIG>. As in the case of pumps <NUM> and <NUM> described supra, compressor <NUM> integrates an electric motor and impeller sections in a compact fashion. With known contra-rotating wet gas compressors, two interleaved sets of impellers are driven in opposite (or contra-rotating) directions using two separate electric motors that are longitudinally offset from the impellers by relatively long shafts or a combination of a sleeve and shaft. In contrast, compressor <NUM> of the disclosure integrates both electric motors with the impellers having permanent magnets mounted thereon. Compressor <NUM> might include an outer stator, an inner stator and two sets impeller sleeves disposed between the two stators that are driven in opposite directions by the two stators. On the outer portion of compressor <NUM> is the outer casing <NUM>, outer stator winding <NUM> and outer stator canning member <NUM>. Near the outer stator winding <NUM> are outer permanent magnets <NUM> that are fixed to an outer sleeve member <NUM>. A plurality of outer impellers <NUM> are fixed to the outer sleeve member <NUM>. An inner stator <NUM> might be canned with inner stator canning member <NUM>. Close to the inner stator windings <NUM> are inner permanent magnets <NUM> that are fixed to inner sleeve member <NUM> and inner impellers <NUM>. The outer stator winding <NUM> generates a rotating electromagnetic field that induces a rotating movement in the magnets <NUM>, outer sleeve member <NUM> and outer impellers <NUM> about a central axis <NUM>. In a similar fashion, an inner stator winding <NUM> generates a rotating electromagnetic field that induces a rotating movement in the magnets <NUM>, inner sleeve member <NUM> and inner impellers <NUM>. The outer and inner impellers are driven in opposite, or contra-rotating, directions. Note that in this example there remains an open central area <NUM><NUM> that can accommodate, for example, passage of a pipeline pig during times when the compressor is not operating. According to some embodiments, the contra-rotating compressor <NUM> includes shielding means (not shown) for electromagnetic effects between each rotor section.

According to some embodiments, flexibility can be provided in speed (i.e. revolutions per minute (RPM)) range and/or in dimensions for the pumps or compressors. Further, the pumps and compressors described herein allow for flexibility in terms of number of rotor sections and/or impeller stages. For example, in <FIG> there are eight pairs of stacked impellers and diffusers shown. However, the number of impeller/diffuser pairs can be modified to greater or lesser numbers, depending upon the particular application. A pump of the disclosure may be provided by including a number of multiphase stages such as shown in <FIG>, followed by a number of single phase stages such as shown in <FIG>.

According to some other embodiments, pump or compressor can be configured to allow different rotational speeds (RPMs) on different impeller stages within the same pump unit. This can be accomplished, for example by altering the number of poles in the stator and rotor section for different impeller stages. This could also be accomplished by varying the number, arrangement and/or polarity of the permanent magnets on the impeller-rotor.

According to some embodiments, the available cross section for an impeller is relatively high as the machine does not need a shaft to drive the impellers and/or a lubrication circuit might not be needed. According to some embodiments, the mechanical effects between impeller steps might be avoided because each impeller is electromechanically driven, and the plurality of impeller stages are not mechanically connected.

According to some other embodiments, the impeller stages may form a converging cross sectional flow area. For example, this might be achieved by reducing outside diameter sequentially per impeller stage from the pump or compressor inlet to the outlet. Alternatively, this might also be achieved by using progressively more material in the center of the impeller for each successive impeller stage (like step-shaped a cone).

Claim 1:
A fluid processing machine comprising:
a first stator (<NUM>) configured to generate a rotating electromagnetic field;
at least one first rotor section internal to the first stator comprising at least one set of axially spaced impellers (<NUM>) each having permanent magnets (<NUM>) located on the outer diameter thereof wherein the first stator is configured to electromagnetically engage with the at least one first rotor section inducing rotation of the at least one first rotor section about a central axis in a first rotational direction thereby causing the at least one impeller to impart kinetic energy on a fluid being processed;
a second stator (<NUM>) configured to generate a rotating electromagnetic field and electromagnetically engage with at least one second rotor section rotatable about the central axis in a second rotational direction opposite to the first rotation direction, the second rotor section comprising at least one set of axially spaced second impellers (<NUM>) having permanent magnets (<NUM>) located on the internal diameter thereof ,
with the second rotor section being internal to the first stator and the second stator being internal to the second rotor section, and
with the impellers (<NUM>) of the at least one first rotor section interleaved with the impellers (<NUM>) of the at least one second rotor section.