High-pressure submersible pump

Abstract

The invention relates to a high-pressure submersible pump with multiple work stages. The pump comprises a fluid inlet and a fluid outlet, and an electric motor with a stator and a rotor, with a shaft extending axially therethrough between a first end and a second end of the motor. At least one work stage is arranged at each end, each with an impeller fixed to the shaft to increase fluid pressure, and a diffuser guiding the fluid from the impeller. The work areas are connected by means of at least one conduit which allows the passage of fluid between them, ensuring a continuous transfer of hydraulic energy. This configuration improves the hydraulic performance, energy efficiency, and mechanical stability of the system, optimizing its operation in demanding conditions.

Description

[0001] HIGH PRESSURE SUBMERSIBLE PUMP

[0002] DESCRIPTION

[0003] OBJECT OF THE INVENTION

[0004] The invention relates to a high-pressure submersible pump with multiple working stages. The pump comprises a fluid inlet and outlet, and an electric motor with a stator and rotor, axially traversed by a shaft extending between a first and second end of the motor. At least one working stage is arranged at each end, each with an impeller fixed to the shaft to increase fluid pressure, and a diffuser that guides the fluid from the impeller. The working stages are connected by at least one conduit that allows fluid to pass between them, ensuring a continuous transfer of hydraulic energy. This configuration improves the hydraulic performance, energy efficiency, and mechanical stability of the system, optimizing its operation under demanding conditions.

[0005] BACKGROUND OF THE INVENTION

[0006] Submersible pumps are widely used devices for extracting or pumping fluids from the media in which they are completely immersed to the outside. These pumps are used when mobility prevents fixed installations and they must be transported; therefore, under these conditions, submersible pumps are ideal.

[0007] The operating principle of these pumps is based on generating pressure through one or more impellers, which are rotating elements responsible for transferring energy to the fluid. In multistage configurations, the pressure increase is achieved through the sequential arrangement of working stages, where each stage consists of a diffuser / impeller assembly. By summing the effect of each stage, a sufficient pressure increase is obtained to raise the fluid to the desired level.

[0008] Existing submersible pumps are typically used in a vertical position, as otherwise the length and weight of the shaft would create a bending moment, damaging the motor bearings. Efforts have been made to extend their use to horizontal configurations with no more than two impellers, since otherwise, extending the shaft would cause vibration and imbalance problems due to impeller wear. In these pumps, as known in the prior art, the motor is coupled to one end of the longitudinally extending shaft, on which the impeller(s) are mounted. Therefore, they only accommodate one or two impellers, which extend from only one end of the motor. Adding more than two impellers to prior art pump models would cause problems with shaft deflection.

[0009] Despite the technical efforts made to date to mitigate these limitations, none of the current state-of-the-art solutions achieve an optimal balance between the number of functional stages, mechanical equilibrium, and thermal management of the system. This combination of problems directly impacts equipment lifespan and operational safety, particularly in environments where predictive maintenance is not feasible.

[0010] In view of these deficiencies, it is necessary to explore other alternatives that overcome the disadvantages of the state of the art, such as configurations that can integrate a greater number of stages without compromising mechanical balance or shaft integrity, that are capable of operating efficiently, and that offer significant improvements in the thermal and dynamic management of the machine.

[0011] DESCRIPTION OF THE INVENTION

[0012] The present invention proposes a solution to the aforementioned problems by means of a high-pressure submersible pump, according to claim 1, configured to provide higher pressure without creating mechanical and / or thermal imbalance. Preferred embodiments of the invention are defined in the dependent claims.

[0013] The inventive aspect of the present invention provides a high-pressure submersible pump with multiple working stages. The submersible pump comprises: a fluid inlet and a fluid outlet; a motor comprising a stator and a rotor, the motor further comprising a first end and a second end; a shaft passing through the rotor and extending in an axial direction at least between the first and second ends of said rotor, forming a first zone and a second zone at the first and second ends of the motor respectively; and at least one working stage for each zone respectively, where each of the at least one working stage comprises:

[0014] ■ an impeller, secured to the shaft, which receives a fluid and is configured to provide the fluid with pressure gain, and

[0015] ■ a diffuser configured to receive fluid from the impeller and configured to guide and direct said fluid; at least one connecting conduit adapted to connect the first zone to the second zone and configured to carry fluid from the first zone to the second zone.

[0016] The submersible pump of the invention allows for a higher pressure to be achieved compared to pumps known in the prior art and, in turn, ensures the balance and overall equilibrium of the forces applied to the device when it is in operating mode.

[0017] In the state of the art, to generate more pressure in a pump, it is necessary to place more impellers on the shaft located at one end of the rotor, which requires extending the shaft, creating an imbalance in the pump.

[0018] However, in the case of the present invention, instead of extending the shaft towards one end of the rotor, the shaft is extended towards both sides of the rotor creating two zones, a first zone and a second zone, while at the same time making use of a connecting duct to communicate said first zone with the second zone and add the working stages, thereby increasing the pressure.

[0019] Furthermore, with the configuration of the present invention, the steering thrusts of the two zones occur in opposite ways, thus compensating for each other and preventing high axial loads, vibration of the shaft / rotor / impeller assembly, and bending or breakage of the shaft due to the lever effect from extending the shaft further and placing more weight at the ends, as is the case with pumps of the prior art.

[0020] The submersible pump of the invention comprises a fluid inlet which is fluidly connected to the first zone and, therefore, to at least one stage of the first zone, i.e., to at least one diffuser and one impeller. In one embodiment where the pump comprises more than one stage in the first zone, the fluid inlet is connected to the first diffuser / impeller assembly of said first zone, preferably the stage of the first zone located closest to the motor.

[0021] Similarly, the submersible pump of the invention comprises a fluid outlet which, in one embodiment, is fluidly connected to the second zone and, therefore, to at least one stage of the second zone, i.e., to at least one diffuser and one impeller. In an embodiment where the pump comprises more than one stage in the second zone, the fluid outlet is connected to the last diffuser / impeller assembly of said second zone, preferably the stage of the second zone located furthest from the motor.

[0022] In each stage, each diffuser is configured in such a way that its opening allows a reduction in fluid speed and an increase in pressure while allowing the fluid to be redirected in the desired direction.

[0023] In one embodiment, the submersible pump of the invention has a symmetrical arrangement of its elements with respect to the axis and / or with respect to the motor, which favors the overall balance of the submersible pump.

[0024] In one embodiment, the first zone is a suction zone and the second zone is a discharge zone. Specifically, the first zone is the suction zone and the second zone is the discharge zone when the number of connecting pipes is odd. When the number of connecting pipes is even, the suction zone and the discharge zone are the same zone.

[0025] In this embodiment, the first zone is a suction zone that allows generating a pressure rise and providing said fluid with pressure gain to the second zone first by sucking the fluid and then transferring the fluid to the second zone through the connecting duct.

[0026] In this embodiment, the second zone is a discharge zone that allows the fluid to be received with pressure gain from the first zone, i.e., the suction zone, and, in this discharge zone, the fluid is also subjected to a pressure gain before being directed towards the outlet of the submersible pump of the invention.

[0027] In one embodiment, the pump further comprises a stator cover configured to enclose the motor stator and adapted to form a main structure upon which the other components are supported. The stator cover allows for motor cooling by dissipating heat with the pumped medium and also provides structural support for the submersible pump. Preferably, the stator cover includes heat-dissipating fins that facilitate heat exchange between the stator cover and the pump's surrounding fluid, enabling more efficient motor cooling, particularly of the motor stator.

[0028] In particular, “other parts” means all parts other than the stator cover and therefore all parts located inside the stator cover.

[0029] In one embodiment, the pump further comprises a volute configured to receive the fluid from the first zone and to redirect the fluid towards the impeller of the second zone.

[0030] The term volute refers to the element that acts as an inlet chamber, meaning it allows the fluid to be distributed homogeneously around the perimeter towards the impeller of the second zone. Preferably, the volute has a spiral shape that decreases in size from its inlet to its outlet.

[0031] In one embodiment, the pump further comprises: a first zone bearing support adapted to support first zone bearings, the first zone bearings being configured to support the axial and radial loads of the first zone impellers; a second zone bearing support adapted to support second zone bearings, the second zone bearings being configured to support the axial and radial loads of the second zone impellers.

[0032] In one particular embodiment, the pump further comprises a housing configured to connect the stator cover to the diffusers of the first zone.

[0033] In a more particular embodiment, the pump further comprises: a first zone cooling chamber located between the first zone bearing support and the crankcase; and a second zone cooling chamber located between the volute and the second zone bearing support; wherein the cooling chambers are preferably oil chambers.

[0034] In one particular embodiment, the pump further comprises a plurality of mechanical seals configured to isolate both ends of the motor, preventing the entry of fluid, and also configured to seal the cooling chambers.

[0035] Advantageously, mechanical seals help prevent the entry of the fluid in which the pump is submerged, ensuring that the only fluid entering the pump is through the fluid inlet of the submersible pump.

[0036] In one embodiment, one of the diffusers in the first zone and one of the blowers in the second zone are connected by a connecting duct.

[0037] In one embodiment, the number of work stages in the first zone and the number of work stages in the second zone are equal; preferably, there is one work stage in each zone or two work stages in each zone.

[0038] Advantageously, by having the same number of working stages in each zone, in the first and second zones, the distribution of axial forces is optimized and allows these forces to be compensated to maintain a balance within the submersible pump of the invention.

[0039] In one embodiment, the connections of at least one connecting duct are made by means of flanges or direct welding.

[0040] In one embodiment, the diffusers comprise a plurality of aligners configured to guide the diffuser fluid and convert kinetic energy into pressure energy.

[0041] In one embodiment, the diffusers comprise sealing means configured to provide sealing in the respective diffusers, the sealing means preferably being o-ring or v-ring type rings.

[0042] In one embodiment, the first zone and the second zone comprise, respectively, impeller clamping means for the first zone and impeller clamping means for the second zone arranged on the shaft, wherein the clamping means are configured to prevent displacement of the respective impellers.

[0043] In one embodiment, the submersible pump comprises: two working stages for each zone respectively, where each of the two working stages comprises:

[0044] ■ an impeller, secured to the shaft, receiving a fluid configured to provide a pressure gain, and a diffuser configured to receive fluid from the impeller and configured to guide and direct said fluid; and a connecting conduit, wherein the connecting conduit carries fluid from the first zone to the second zone such that the sum of working stages in each zone represents the total working stages of the submersible pump; wherein the first zone comprises a first working stage comprising a primary impeller and a primary diffuser, and the first zone further comprises a second working stage comprising a secondary impeller and a secondary diffuser, wherein the first working stage is arranged axially between the impeller and the second working stage;The second zone comprises a third working stage comprising a secondary impeller and a secondary diffuser, and the second zone further comprises a fourth working stage comprising a primary impeller and a primary diffuser, wherein the third working stage is arranged axially between the rotor and the fourth working stage; and the second working stage is connected to the third working stage by means of the connecting conduit so that a fluid entering the pump follows the sequence in order: first stage, second stage, third stage and fourth stage.

[0045] The operation of a submersible pump is based on the efficient conversion of kinetic energy into potential energy (pressure), according to the principles of fluid dynamics. As the fluid enters through the impeller eye, this component transfers velocity to the fluid, generating kinetic energy. Subsequently, as the fluid exits the impeller and travels through the diffuser channels, the progressively expanded design of the passages causes a decrease in fluid velocity and, consequently, an increase in pressure, according to Bernoulli's principle. This energy transformation is fundamental for lifting the fluid through the conduit, allowing it to reach the desired pressure point. The submersible pump's configuration ensures optimal energy transfer, improving hydraulic performance and overall pump efficiency.

[0046] In one embodiment, where the number of working stages in the first zone and the number of working stages in the second zone are not equal, the submersible pump comprises: a working stage in the first zone, where said working stage comprises an impeller secured to the shaft, which receives a fluid configured to provide a pressure gain thereto, and a diffuser configured to receive fluid from the impeller and configured to guide and direct said fluid; two working stages in the second zone, where each of the two working stages comprises:

[0047] ■ an impeller, secured to the shaft, receiving a fluid configured to provide pressure gain, and a diffuser configured to receive fluid from the impeller and configured to guide and direct said fluid; and a connecting conduit, wherein the connecting conduit carries fluid from the first zone to the second zone such that the sum of working stages in each zone represents the total working stages of the submersible pump; wherein the first zone comprises a first working stage comprising a primary impeller and a primary diffuser, the second zone comprises a second working stage comprising a secondary impeller and a secondary diffuser, and the second zone further comprises a third working stage comprising a primary impeller and a primary diffuser, wherein the second working stage is arranged axially between the rotor and the third working stage;The first working stage is connected to the second working stage via a connecting pipe, so that a fluid entering the pump follows the sequence: first stage, second stage, third stage. Advantageously, this embodiment allows for a wider pressure range and enables the pump outlet pressure to be adjusted to the required pressure when lower outlet pressure requirements exist. In this embodiment, axial stress compensation occurs between the stresses exerted by the first stage and the axial stresses of the second and third stages. In either case, whether with the same number of stages in each zone or a different number of stages in each zone, the maximum distance between a stage and the motor is reduced by distributing the stages on either side of the motor, resulting in less shaft deflection.

[0048] In this embodiment, if there is an imbalance of axial forces, the bearings are what would support that difference.

[0049] In a preferred embodiment, all the impellers of the submersible pump of the invention have the same vane configuration.

[0050] In one embodiment, the submersible pump comprises: two working stages for each zone respectively, where each of the two working stages comprises:

[0051] ■ an impeller, secured to the shaft, receiving a fluid configured to provide it with pressure gain, and a diffuser configured to receive fluid from the impeller and configured to guide and direct said fluid; and two connecting conduits, a first connecting conduit and a second connecting conduit, wherein each connecting conduit carries fluid from the first zone to the second zone and from the second zone to the first zone respectively, such that the sum of working stages in each zone represents the total working stages of the submersible pump;wherein the first zone comprises a first working stage comprising a first zone primary impeller and a first zone primary diffuser, and the first zone further comprises a second working stage comprising a first zone secondary impeller and a first zone secondary diffuser, wherein the first working stage is arranged axially between the rotor and the second working stage; the second zone comprises a third working stage comprising a second zone secondary impeller and a second zone secondary diffuser, and the second zone further comprises a fourth working stage comprising a second zone primary impeller (149) and a second zone primary diffuser (148), wherein the third working stage is arranged axially between the rotor (101) and the fourth working stage;and the first working stage is connected to the third working stage by means of the first connecting pipe, and additionally the fourth working stage is connected to the second working stage by means of the second connecting pipe, so that a fluid entering the pump follows in order the sequence: first stage, third stage, fourth stage, second stage.;

[0052] In one embodiment where the submersible pump includes mechanical seals, the arrangement of the elements in this embodiment of the submersible pump of the invention allows for optimized pressure compensation and reduces the load on the mechanical seals. Specifically, in this embodiment, the mechanical seals are not subjected to the pressure generated in both zones, but only to the pressure generated during the first operating stage of the first zone.

[0053] This embodiment of the submersible pump reduces the pressure load on the mechanical seals. In the embodiment where the submersible pump has only one connection pipe, the mechanical seals received the combined pressure from the impellers in the first zone. In one specific case, this pressure could exceed 20 bar, which is a critical limit for conventional mechanical seals.

[0054] With the two-channel design of this embodiment, the mechanical seals only receive the pressure generated in the primary impeller of the first zone, thus preventing overloads and optimizing pressure compensation on the shaft. Furthermore, this design also improves hydraulic balance and reduces the risk of leaks or failures in the mechanical seals, without compromising the overall efficiency of the pump.

[0055] Thanks to this redistribution of flow, a more efficient design is achieved, with less wear on mechanical seals, a reduction in vibrations and better load compensation, which prolongs the pump's lifespan without compromising its pumping capacity.

[0056] In one particular embodiment, the pump further comprises a first volute in the second zone, the first volute being configured to receive the flow from the first connecting conduit and to redirect the fluid inlet towards the secondary impeller of the second zone.

[0057] In a more particular embodiment, the pump further comprises a second volute in the first zone, the second volute being configured to receive the flow from the second connecting conduit and to redirect the fluid inlet, by means of aligners, towards the center of the primary impeller of the second zone.

[0058] DESCRIPTION OF THE DRAWINGS

[0059] These and other features and advantages of the invention will become clearer from the following detailed description of a preferred embodiment, given only as an illustrative and non-limiting example, with reference to the accompanying figures.

[0060] Figure 1 This figure shows a front view of a submersible pump according to a first embodiment of the invention.

[0061] Figure 2A This figure shows an enlargement of the first zone according to an embodiment of the invention.

[0062] Figure 2b This figure shows an enlargement of the second zone according to an embodiment of the invention.

[0063] Figure 3 This figure shows a front view of a second embodiment of a submersible pump according to the invention.

[0064] Figure 4 This figure shows a front view of a third embodiment of a submersible pump according to the invention.

[0065] Figure 5. This figure shows a front view of a fourth embodiment of a submersible pump according to the invention. DETAILED DESCRIPTION OF THE INVENTION

[0066] The present invention provides a high-pressure submersible pump with multiple working stages. The submersible pump comprises: a fluid inlet and a fluid outlet; a motor comprising a stator (2, 102) and a rotor (1, 101), the motor further comprising a first end and a second end; a shaft (4, 104) passing through the rotor (1, 101) and extending axially at least between the first and second ends of said rotor (1), forming a first zone (72, 172) and a second zone (73, 173) at the first and second ends of the motor, respectively; and at least one working stage for each zone (72, 172, 73, 173), where each of the at least one working stage comprises:

[0067] ■ an impeller (17, 22, 49, 51, 117, 122, 149, 151), secured to the shaft (4, 104), which receives a fluid and is configured to provide the fluid with pressure gain, and

[0068] ■ a diffuser (18, 23, 45, 48, 118, 123, 145, 148) configured to receive fluid from the impeller (17, 22, 49, 51, 117, 122, 149, 151) and configured to guide and direct said fluid; at least one connecting conduit (25, 125, 181) adapted to connect the first zone (72, 172) with the second zone (73, 173) and configured to carry fluid from the first zone (72, 172) to the second zone (73, 173).

[0069] In particular, Figure 1 shows an embodiment of the submersible pump of the invention where the submersible pump comprises: two working stages for each zone respectively (72, 73), where each of the two working stages comprises:

[0070] ■ an impeller (17, 22, 49, 51), secured to the shaft (4), receiving a fluid configured to provide pressure gain, and a diffuser (18, 23, 45, 48) configured to receive fluid from the impeller and configured to guide and direct said fluid; and a connecting conduit (25), wherein the connecting conduit carries fluid from the first zone (72) to the second zone (73) such that the sum of working stages in each zone represents the total working stages of the submersible pump; wherein the first zone (72) comprises a first working stage comprising a primary impeller (17) and a primary diffuser (18), and the first zone (72) further comprises a second working stage comprising a secondary impeller (22) and a secondary diffuser (23), wherein the first working stage is arranged axially between the rotor (1) and the second working stage;the second zone (73) comprises a third working stage comprising a secondary impeller (51) and a secondary diffuser (45), and the second zone (73) further comprises a fourth working stage comprising a primary impeller (49) and a primary diffuser (48), wherein the third working stage is arranged axially between the rotor (1) and the fourth working stage; and the second working stage is connected to the third working stage by means of the connecting conduit (25) so that a fluid entering the pump follows the sequence in order: first stage, second stage, third stage, fourth stage.

[0071] In the embodiment of figure 1, the motor comprises a stator (2), which is a set of steel plates with a set of copper wire coils, and in the inner part of the stator (2) there is a rotor (1) which has a first end and a second end.

[0072] The shaft (4), which in some embodiments of the invention is a machined cylindrical bar, is supported by bearings (6, 28), one in the first zone (72) and another in the second zone (73). Additionally, in this embodiment, the pump has two working stages per zone, each working stage comprising: an impeller (17, 22, 49, 51), secured to the shaft (4), which receives a fluid to provide it with pressure gain, and a diffuser (18, 23, 45, 48) which receives fluid from the impeller (17, 22, 49, 51) to guide and direct said flow.

[0073] In one embodiment, such as that shown in Figure 1, the first zone (72) is a suction zone and the second zone (73) is a discharge zone. In the embodiment illustrated in Figure 1, both the suction zone (72) and the discharge zone (73) have two impellers (17, 22, 49, 51) and two diffusers (18, 23, 45, 48), resulting in a total of four working stages.

[0074] The first working stage consists of a primary impeller (17) and a primary diffuser (18); while the second working stage consists of a secondary impeller (22) and a secondary diffuser (23), both located in the first zone (72). The third working stage, in the discharge zone (73), consists of a secondary impeller (51) and a secondary diffuser (45). Finally, the fourth working stage consists of a primary impeller (49) and a primary diffuser (48).

[0075] Also in the realization of figure 1, the submersible pump comprises a strainer (14) or filter, which is a rolled perforated plate that is located around a crankcase (12) and that allows preventing the entry of solids according to the diameter of the holes in the first zone (72) of the pump, said strainer (14) is arranged in the admission of the primary impeller (17) of the first zone (72).

[0076] In the first zone (72), the shaft (4) is supported on bearings (6) of the first zone (72), the bearings (6) of the first zone (6) being configured to support the axial and radial loads of the first zone impellers (17, 22).

[0077] In the embodiment of Figure 1, the submersible pump further comprises a stator cover (3) and within said stator cover (3) is a motor, in particular an electric motor, powered by electrical power cables and the cables are connected to the motor by passing through cable inlets.

[0078] The cable entry seals the fluid inlet to the motor by sealing the space between the cable and the entry itself. Furthermore, in this embodiment, the submersible pump also includes a cable seal made of a suitable material, such as rubber or elastomer, that can deform and conform to the shape of the opening.

[0079] Furthermore, in this embodiment, a cable clamp is provided that presses against the cable seal by having a male thread at the base and a female cable entry, exerting pressure so that the cable seal expands, thus preventing fluid ingress. Likewise, the submersible pump embodiment of Figure 1 includes a housing (65) that allows for electrical connections, and a housing cover (64) that is sealed with an O-ring and threaded bolts. In Figure 1, a bearing cover bearing seal (8) is shown where a first mechanical seal (9) is located which is in contact with a coolant (e.g., oil) from a cooling chamber (70) of the first zone (72) located between the bearing support (7) of the first zone (72) and the crankcase (12) that cools the contact faces, while on the other side of the cooling chamber (70) of the first zone (72) is a second mechanical seal (62) housed in the crankcase (12).

[0080] The first mechanical seal (9) isolates the fluid from the bearing side (6) of the first zone (72). A first cover (5) is bolted to threaded holes in the bearing support (7) of the first zone (72). Following this is the primary impeller (17) of the first zone (72), and then the primary diffuser (18) of the first zone (72), which directs the fluid after it exits the primary impeller (17) of the first zone (72), thereby increasing the pressure.

[0081] Downstream of the primary diffuser (18) of the first zone (72) is the secondary impeller (22) of the first zone (72), which, as it rotates, discharges the fluid towards the secondary diffuser (23) of the first zone (72). The latter is connected by a bolted flange to a connecting pipe (25). In this first zone (72), the pressure from the impellers (17, 22) of the first zone (72) is added. Between each set of impellers in the first zone (72) is a first spacer (19) (see Fig. 2A) that maintains the distance between these pairs of impellers (17, 22). First impeller fastening means (24), such as a bolt or nut, arranged at the end of the shaft (4) (for example, on the shaft edge), prevent displacement of the secondary (22) and primary (17) impellers of the first zone (72), thus retaining the assembly.

[0082] Furthermore, the first zone (72) comprises a first suction cover (63) and a second suction cover (21), which are attached to the primary diffuser (18) of the first zone (72) by means of a pressure-fit system having a fixing stud (68) (Fig. 2A) from the secondary diffuser (23) of the first zone (72). In addition, further fastening means at one end of the first suction cover (63) secure it to the crankcase (12) (e.g., by means of bolts).

[0083] In some embodiments, the components, instead of being joined by a fixing stud, are joined in pairs or in another configuration by means of fasteners such as bolts. The connecting conduit (25) connects the first zone, the suction zone (72), and the second zone, the discharge zone (73) of the pump, carrying fluid from one zone to the other.

[0084] In the second zone (73), the other end of the rotor (1) is located, the shaft (4) in that zone being supported by bearings (28) of the second zone (73), which are housed in a bearing support (30) of the second zone (73) which is attached to the stator cover (3), for example, by bolts.

[0085] Likewise, as in the first zone (72), to seal the side of the motor near the second zone (73) and the bearings (28) of that zone, the submersible pump comprises a cooling chamber (71) of the second zone (73) which at one end has the bearing support (30) of the second zone (73) and at the other end a volute (41) (Fig. 2B), wherein the cooling chamber (71) of the second zone (73) is sealed with mechanical seals (40, 43).

[0086] In some embodiments of the invention, the coolant in the cooling chamber (71) of the second zone (73) is oil. On the bearing side (28) of the second zone (73) there is a third mechanical seal (40) on the bearing support (30) of the second zone (73) which has a cover housing (27) coupled to said bearing support (30) of the second zone (73) and at the other end a fourth mechanical seal (43) which has a seal-carrying cover (44).

[0087] Next, the secondary impeller (51) of the second zone (73) is shown, which receives the fluid from the first zone (72), and discharges to the secondary diffuser (45) of the second zone (73) which directs the fluid to the primary impeller (49) of the second zone (73) and at its outlet the fluid is directed towards the primary diffuser (48) of the second zone (73), increasing the pressure with the sum of all the impellers and, finally, towards the outlet of the submersible pump.

[0088] The second zone (73) comprises a first cover (46), a second cover (50), and a third cover (67), which are attached to the secondary diffuser (45) of the second zone (73) and to the primary diffuser (48) of the second zone (73) by means of a pressure-fit system having a fixing stud (55) extending from the third cover (67) to the second cover (50), which, in turn, is attached to the volute (41) (Fig. 2B) by means of suitable fastening means. In some embodiments, the components, instead of being joined by a fixing stud, are joined one by one by means of fastening means such as bolts.

[0089] A second spacer horn (53) (Fig. 2B) allows the distance between each set of impellers (51, 49) of the second zone (73) to be maintained. Second impeller fastening means (54), such as a bolt or nut, fasten the secondary impeller (51) of the second zone (73) and the primary impeller (49) of the second zone (73) to the shaft (4), so that they do not exhibit longitudinal displacement with respect to the shaft (4).

[0090] In some embodiments, in one or both zones, the diffusers (45, 23, 18, 48) are connected to the impellers (17, 49, 51, 22) by means of a plurality of keys. Likewise, in some embodiments, the system for securing the impellers (17, 49, 51, 22) to the shaft (4) for transmitting rotation is by means of keys that are anchored to the shaft (4) and allow their respective rotation.

[0091] Additionally, in some embodiments of the invention, the keys that hold the impellers (17, 49, 51, 22) to the shaft (4) are made of steel, each key fitting into a channel in the shaft (4) and entering through a channel in the impeller.

[0092] In some embodiments of the invention, the impellers (17, 49, 51, 22) can be open or semi-open; while in others they can be closed.

[0093] Additionally, in some embodiments of the invention, one or more diffusers are sealed with an O-ring to achieve a leak-proof seal. The O-ring can be made of various materials such as Viton, nitrile, and Buna. In other embodiments, the seal is achieved using a V-ring.

[0094] In some embodiments of the invention, the diffusers (45, 23, 18, 48) comprise at least two aligners that help direct the flow more efficiently and uniformly, reducing turbulence and improving the hydraulic performance of the pump of the invention. Likewise, in some embodiments of the invention, the material of the impellers (17, 49, 51, 22) and diffusers (45, 23, 18, 48) is selected independently from the group comprising iron, steel, and / or stainless steel.

[0095] In some embodiments of the invention, the number of working stages in each zone (72, 73) is the same, so that a load balance is obtained in both zones. In other embodiments of the invention, the number of working stages in each zone is at least two; wherein, in each zone (72, 73), the submersible pump comprises a clamping system or means between the diffusers (45, 23, 18, 48) of each zone (72, 73).

[0096] Figures 2A and 2B show respectively enlargements of the first zone (72) and the second zone (73) of a pump according to the same embodiment described in Figure 1.

[0097] In one embodiment, as shown in Figure 3, the submersible pump comprises: a working stage in the first zone (72), wherein said working stage comprises an impeller (17) secured to the shaft (4), which receives a fluid configured to provide it with a pressure gain, and a diffuser (18) configured to receive fluid from the impeller and configured to guide and direct said fluid; two working stages in the second zone (73), wherein each of the two working stages comprises:

[0098] ■ an impeller (49, 51), secured to the shaft (4), receiving a fluid configured to provide pressure gain, and a diffuser (45, 48) configured to receive fluid from the impeller and configured to guide and direct said fluid; and a connecting conduit (25), wherein the connecting conduit carries fluid from the first zone (72) to the second zone (73) such that the sum of working stages in each zone represents the total working stages of the submersible pump;wherein the first zone (72) comprises a first working stage comprising a primary impeller (17) and a primary diffuser (18), the second zone (73) comprises a second working stage comprising a secondary impeller (51) and a secondary diffuser (45), and the second zone (73) further comprises a third working stage comprising a primary impeller (49) and a primary diffuser (48), wherein the second working stage is arranged axially between the rotor (1) and the third working stage; and the first working stage is connected to the second working stage by means of the connecting conduit (25) so that a fluid entering the pump follows the sequence: first stage, second stage, third stage.

[0099] In this embodiment, where the fluid path is indicated by the arrows shown in Figure 3, the submersible pump further comprises a first volute (10) and a second volute (41). The fluid enters the pump through the pump inlet and, after passing through the first volute (10), is directed to the first working stage, i.e., by the primary impeller (17) and a primary diffuser (18), the only working stage of the first zone (72).

[0100] The fluid is then conveyed to the second zone (73) via the connecting pipe (25). Specifically, the fluid is conveyed from the first working stage to the second working stage, which is part of the two working stages of the second zone (73). After passing through the second and third working stages, both of the second zone (73), the fluid undergoes a pressure increase before being discharged from the pump outlet, i.e., after passing through the secondary impeller (51), a secondary diffuser (45), the primary impeller (49), and the primary diffuser (48).

[0101] In one embodiment, shown in Figure 4, the submersible pump comprises a single working stage in each zone where each working stage comprises an impeller (17), secured to the shaft, which receives a fluid configured to provide it with pressure gain, and a diffuser (18) configured to receive fluid from the impeller (17) and configured to guide and direct said fluid.

[0102] The submersible pump of the present embodiment further comprises a connecting conduit (25), wherein the connecting conduit (25) carries fluid from the first zone to the second zone such that the sum of working stages in each zone (72, 73) represents the total working stages of the submersible pump.

[0103] In this same embodiment, the first zone (72) comprises a first working stage comprising a primary impeller (17) and a primary diffuser (18), and wherein the second zone (73) comprises a second working stage comprising a secondary impeller (49) and a secondary diffuser (48), and the first working stage is connected to the second working stage by means of the connecting duct (25) so that a fluid entering the pump follows in order the sequence: first stage, second stage.

[0104] Figures 3 and 4 include only the numerical references relevant to understanding this embodiment of the invention and where it differs from other embodiments. Other common numerical references, such as those for the rotor and shaft, which have been previously described, are not included in Figures 3 and 4 for clarity and to avoid overloading the figures with references.

[0105] In particular, Figure 5 shows a fourth embodiment of the submersible pump of the invention where the submersible pump comprises: two working stages for each zone respectively (172, 173), where each of the two working stages comprises:

[0106] ■ an impeller (117, 122, 149, 151), secured to the shaft (104), receiving a fluid (180) configured to provide pressure gain, and a diffuser (118, 123, 145, 148) configured to receive fluid (180) from the impeller and configured to guide and direct said fluid (180); and two connecting conduits (125, 181), a first connecting conduit (125) and a second connecting conduit (181), where each connecting conduit carries fluid (180) from the first zone (172) to the second zone (173) and from the second zone (173) to the first zone (172) respectively, such that the sum of working stages in each zone represents the total working stages of the submersible pump;wherein the first zone (172) comprises a first working stage comprising a primary impeller (117) and a primary diffuser (118), and the first zone (172) further comprises a second working stage comprising a secondary impeller (122) and a secondary diffuser (123), wherein the first working stage is arranged axially between the rotor (101) and the second working stage; the second zone (173) comprises a third working stage comprising a secondary impeller (151) and a secondary diffuser (145), and the second zone (173) further comprises a fourth working stage comprising a primary impeller (149) and a primary diffuser (148), wherein the third working stage is arranged axially between the rotor (101) and the fourth working stage;and the first working stage is connected to the third working stage by means of the first connecting conduit (125), and additionally the fourth working stage is connected to the second working stage by means of the second connecting conduit (181), so that a fluid (180) entering the pump follows in order the sequence: first stage, third stage, fourth stage, second stage.;

[0107] In this regard, Figure 5 shows a submersible pump comprising a motor having a stator (102) and a rotor (101) with two ends. A stator cover (182) is immersed in the fluid to be pumped and dissipates the operating temperature of the motor stator (102) located between the first zone (172) and the second zone (173).

[0108] Furthermore, the pump comprises a shaft (104) that passes through the rotor (101) and extends in an axial direction at least between the first end and the second end of said rotor (101), forming a first zone (172) and a second zone (173) at the first and second ends of the rotor respectively.

[0109] Likewise, the pump in Figure 5 has at least two working stages for each zone (172, 173), each working stage comprising: an impeller (117, 122, 149, 151), secured to the shaft (104), which receives a fluid to provide kinetic energy to the fluid, and a diffuser (118, 123, 145, 148) which receives fluid from the impeller (117, 122, 149, 151) to guide and direct said fluid and generate potential energy.

[0110] The same pump in Figure 5 also comprises two connecting conduits: a first connecting conduit (125) and a second connecting conduit (181). These connecting conduits (125, 181) are necessary to allow the redistribution of the fluid path (180). Each connecting conduit (125, 181) carries fluid (180) from one zone to another, from the first zone (172) to the second zone (173) and from the second zone (173) to the first zone (172) respectively, such that the sum of working stages in each zone (172, 173) represents the total working stages of the submersible pump.

[0111] The submersible pump, of the embodiment shown in Figure 5, further comprises a fluid inlet volute (114) that acts as an inlet collector and directs the fluid (180) towards a primary impeller (117) of the first zone (172).

[0112] In other embodiments, equivalent to that shown in Figure 1, instead of the fluid inlet volute (114) a filter (14) and a chamber are provided (not shown in Fig. 1).

[0113] The submersible pump further comprises: a first external mechanical seal of the first zone (162) in contact with the fluid (180) entering the pump, and is therefore subjected to pressure close to atmospheric pressure; and a second external mechanical seal of the second zone (143) in contact with the fluid (180) entering the second zone (173) after passing through the first working stage, and therefore through the primary impeller / primary diffuser assembly (117, 118) of the first zone (172). In this respect, the fluid (180) is conveyed from the first zone (172) to the second zone (173) via the first connecting conduit (125).

[0114] The fluid then passes through the third working stage located in the second zone (173), where it experiences another pressure increase before passing through the fourth working stage. Upon exiting the fourth working stage, the fluid (180) returns to the first zone (172) via the second connecting pipe (181) and finally passes through the second working stage. Therefore, the fluid (180) entering the submersible pump follows this sequence: first stage, third stage, fourth stage, second stage.

[0115] This ensures that the second external mechanical seal of the second zone (143), instead of being subjected to the pressure gains of the first and second working stages of the first zone (172), is only subjected to the pressure gain of the first working stage, effectively reducing the risk of damage to this seal. At the same time, having at least two connecting ducts (125, 181) allows the number of working stages to be adjusted to achieve the required performance. The primary diffuser of the first zone (118) is connected to the secondary impeller (151) of the second zone (173) via the first connecting duct (125). In the embodiment shown in Figure 2, this connection is achieved via a first volute (141), such that the first connecting duct (125) connects to both the first volute (141) and the primary diffuser (118) of the first zone (172).

[0116] Likewise, the primary diffuser (148) of the second zone (173) is in communication with the secondary impeller (122) of the first zone (172) through the first connecting duct (125).

[0117] In the embodiment shown in Figure 3, this communication is achieved by means of the secondary diffuser (123) of the first zone (172), which is configured so that the fluid (180) enters radially and exits axially. In this embodiment, the second connecting duct (181) establishes a connection between the primary diffuser (148) of the second zone (173) and the secondary diffuser (123) of the first zone (172).

[0118] In this, other embodiments, or all embodiments of the invention, the connections to the connecting conduits (125, 181) are made by means of flanges or direct welding. Furthermore, in one or more embodiments of the invention, the connecting conduits (125, 181) are made of at least one material selected from the group comprising steel, rubber, and polyethylene.

[0119] In one or many embodiments of the invention, one or more diffusers (118, 123, 145, 148) are sealed with o-rings or v-rings to provide sealing.

[0120] In one or more embodiments, the submersible pump comprises one or more additional working stages arranged between the first and second working stages. Likewise, independently or simultaneously with the additional stages of the first stage, the submersible pump comprises one or more additional working stages arranged between the third and fourth working stages.

[0121] In one or several embodiments, the number of working stages in each zone (172, 173) is the same. Specifically, in one group of embodiments, the number of working stages in each zone (172, 173) is two, making the total number of working stages of the submersible pump four.

Claims

CLAIMS 1. A high-pressure submersible pump with multiple working stages, the submersible pump comprising: a fluid inlet and a fluid outlet; a motor comprising a stator (2, 102) and a rotor (1, 101), the motor further comprising a first end and a second end; a shaft (4, 104) passing through the rotor (1, 101) and extending in an axial direction at least between the first end and the second end of said rotor (1, 101), forming a first zone (72, 172) and a second zone (73, 173) at the first and second ends of the motor respectively; at least one working stage for each zone (72, 172, 73, 173) respectively, where each of the at least one working stage comprises: ■ an impeller (17, 22, 49, 51, 117, 122, 149, 151), secured to the shaft (4, 104), which receives a fluid and is configured to provide the fluid with pressure gain, and ■ a diffuser (18, 23, 45, 48, 118, 123, 145, 148) configured to receive fluid from the impeller (17, 22, 49, 51, 117, 122, 149, 151) and configured to guide and direct said fluid; at least one connecting conduit (25, 125, 181) adapted to connect the first zone (72, 172) with the second zone (73, 173) and configured to carry fluid from the first zone (72, 172) to the second zone (73, 173).

2. The submersible pump according to claim 1, wherein the first zone (72) is a suction zone and the second zone (73) is a discharge zone.

3. The submersible pump according to any of the preceding claims, wherein the pump further comprises a stator cover (3) configured to cover the motor stator (2, 102) and adapted to form a main structure on which the other parts are supported. 4.- The submersible pump according to any of the preceding claims, wherein the pump further comprises a volute (41) configured to receive the fluid from the first zone (72) and to redirect the fluid towards the impeller of the second zone (73).

5. The submersible pump according to any of the preceding claims, wherein the pump further comprises: a bearing support (7) of the first zone (72) adapted to support bearings (6) of the first zone (72), the bearings (6) of the first zone (72) being configured to support the axial and radial loads of the impellers (17, 22) of the first zone (72); a bearing support (30) of the second zone (73) adapted to support bearings (28) of the second zone (73), the bearings (28) of the second zone (73) being configured to support the axial and radial loads of the impellers (49, 51) of the second zone (73). 6.- The submersible pump according to any of claims 3 to 5, wherein the pump further comprises a housing (12) configured to join the stator cover (3) with the diffusers (18, 23) of the first zone (72).

7. The submersible pump according to claims 5 and 6, wherein the pump further comprises: a cooling chamber (70) of the first zone (72) located between the bearing support (7) of the first zone (72) and the housing (12); and a cooling chamber (71) of the second zone (73) located between the volute (41) and the bearing support (30) of the second zone (73); wherein the cooling chambers (70, 71) are preferably oil chambers.

8. The submersible pump according to claim 7, wherein the pump further comprises a plurality of mechanical seals (9, 40, 43, 62) configured to isolate both ends of the motor, preventing the entry of fluid, and also configured to seal the cooling chambers (70, 71). 9.- The submersible pump according to any of the preceding claims, wherein one of the diffusers (23) of the first zone (72) and one of the impellers (51) of the second zone (73) are connected by a connecting duct (25).

10. The submersible pump according to any of the preceding claims, wherein the first zone (72) and the second zone (73) comprise respectively first impeller clamping means (24) and second clamping means of impellers (54) arranged on the shaft (4), where the clamping means are configured to prevent displacement of the respective impellers (17, 22, 49, 51). 11 The submersible pump according to any of the preceding claims, wherein the submersible pump comprises: two working stages for each zone respectively (72, 73), wherein each of the two working stages comprises: ■ an impeller (17, 22, 49, 51), secured to the shaft (4), receiving a fluid configured to provide pressure gain, and a diffuser (18, 23, 45, 48) configured to receive fluid from the impeller and configured to guide and direct said fluid; and a connecting conduit (25), wherein the connecting conduit carries fluid from the first zone (72) to the second zone (73) such that the sum of working stages in each zone represents the total working stages of the submersible pump; wherein the first zone (72) comprises a first working stage comprising a primary impeller (17) and a primary diffuser (18), and the first zone (72) further comprises a second working stage comprising a secondary impeller (22) and a secondary diffuser (23), wherein the first working stage is arranged axially between the rotor (1) and the second working stage;the second zone (73) comprises a third working stage comprising a secondary impeller (51) and a secondary diffuser (45), and the second zone (73) further comprises a fourth working stage comprising a primary impeller (49) and a primary diffuser (48), wherein the third working stage is arranged axially between the rotor (1) and the fourth working stage; and; The second working stage is connected to the third working stage by means of the connecting conduit (25) so that a fluid entering the pump follows the sequence in order: first stage, second stage, third stage, fourth stage.

12. The submersible pump according to any of claims 1 to 10, wherein the submersible pump comprises: a working stage in the first zone (72), wherein said working stage comprises an impeller (17) secured to the shaft (4), which receives a fluid configured to provide a pressure gain thereto, and a diffuser (18) configured to receive fluid from the impeller and configured to guide and direct said fluid; two working stages in the second zone (73), wherein each of the two working stages comprises: ■ an impeller (49, 51), secured to the shaft (4), receiving a fluid configured to provide pressure gain, and a diffuser (18, 23, 45, 48) configured to receive fluid from the impeller and configured to guide and direct said fluid; and a connecting conduit (25), wherein the connecting conduit carries fluid from the first zone (72) to the second zone (73) such that the sum of working stages in each zone represents the total working stages of the submersible pump;wherein the first zone (72) comprises a first working stage comprising a primary impeller (17) and a primary diffuser (18), the second zone (73) comprises a second working stage comprising a secondary impeller (51) and a secondary diffuser (45), and the second zone (73) further comprises a third working stage comprising a primary impeller (49) and a primary diffuser (48), wherein the second working stage is arranged axially between the rotor (1) and the third working stage; and; The first working stage is connected to the second working stage by means of the connecting conduit (25) so that a fluid entering the pump follows the sequence in order: first stage, second stage, third stage.

13. The submersible pump according to claim 1, wherein the submersible pump comprises: two working stages for each zone respectively (172, 173), wherein each of the two working stages comprises:■ an impeller (117, 122, 149, 151), secured to the shaft (104), receiving a fluid (180) configured to provide pressure gain, and a diffuser (118, 123, 145, 148) configured to receive fluid (180) from the impeller and configured to guide and direct said fluid (180); and two connecting conduits (125, 181), a first connecting conduit (125) and a second connecting conduit (181), where each connecting conduit carries fluid (180) from the first zone (172) to the second zone (173) and from the second zone (173) to the first zone (172) respectively, such that the sum of working stages in each zone represents the total working stages of the submersible pump;wherein the first zone (172) comprises a first working stage comprising a first zone (172) primary impeller (117) and a first zone (172) primary diffuser (118), and the first zone (172) further comprises a second working stage comprising a secondary impeller (122) and a secondary diffuser (123), wherein the first working stage is arranged axially between the rotor (101) and the second working stage; the second zone (173) comprises a third working stage comprising a secondary impeller (151) and a secondary diffuser (145), and the second zone (173) further comprises a fourth working stage comprising a primary impeller (149) and a primary diffuser (148), wherein the third working stage is arranged axially between the rotor (101) and the fourth working stage; and; The first working stage is connected to the third working stage by means of the first connecting pipe (125), and additionally the fourth working stage is connected to the second working stage by means of the second connecting pipe (181), so that a fluid (180) entering the pump follows in order the sequence: first stage, third stage, fourth stage, second stage. 14.- The submersible pump according to claim 13, wherein the pump further comprises a first volute (141) in the second zone (73), the first volute (141) being configured to receive the flow from the first connecting conduit (125) and to redirect the fluid inlet towards the secondary impeller (151) of the second zone (173).

15. The submersible pump according to claim 13 or 14, wherein the pump further comprises a second volute in the first zone (173), the second volute being configured to receive the flow from the second connecting conduit (181) and to redirect the fluid inlet (180) towards the fluid outlet of the submersible pump.

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