Marine turbines that harness kinetic and potential energy

Abstract

The present invention includes an apparatus for harnessing the kinetic energy of ocean currents, seas, or estuaries by transferring the kinetic energy of the water to a turbine that drives a generator. The apparatus consists of several parts, mainly including: A) an ejector pump with an intake and a mixing chamber, and B) a cross-flow turbine M1 (revolving door type, two blades).

Description

[Technical Field]

[0001] The present invention relates to a device or apparatus designed to harness the kinetic energy of ocean currents or estuaries. The kinetic energy of water is converted into mechanical energy and then into usable electrical energy. The most important ocean currents are found in ocean movements caused by the Earth's rotation, characterized by the permanent movement of large volumes of water along continental coasts. Their exploitation can ensure high load factors for power generation. Other forms of ocean kinetic energy are harnessed through tidal fluctuations and dams or installations directly located in the current or wave motion. This invention focuses primarily on the first form, which includes harnessing the kinetic energy of ocean currents or the permanent flow of rivers, estuaries, or waterways without necessarily relying on dams. The European Marine Energy Centre (EMEC, http: / / www.emec.org.uk) classifies such devices. The field of interest of this invention is marine energy, ocean energy, and marine hydrokinetic energy (MHK), excluding wave energy and tidal sea level fluctuations (although tidal fluctuations may be applicable at certain times to increase efficiency). [Background technology]

[0002] The use of marine hydrokinetic energy from water dates back to Roman waterwheels and Greek writings on their applications in Egypt. These were used to extract energy from water, particularly for crushing, transportation, and pumping to different levels for military purposes. With the advent of the industrial era, large-scale hydroelectric projects on rivers began, and experience in hydraulic design, construction, and hydroelectric power generation was accumulated. Environmental conflicts due to ecosystem impacts, high initial investment costs, and the need for competitive returns led to a shift in investment to explore new options, focusing on the great potential of ocean currents. To meet these new challenges, several technological solutions have been proposed, including axial rotor generators, vertical axis rotors (operating in cross currents), and oscillating blades that interact with the current. Examples include SeaGen, Thawt, Lanstrom, Vivace, and Gesmey. The development of these technologies was initially driven by the need to replace generated heat with renewable energy in the face of global warming or geopolitical motivations. The technical background of these devices includes experience in wind energy utilization, marine propeller or turbine research, knowledge of hydro-aerodynamics, water turbines in general, and hydroelectric power expertise.

[0003] At EMEC (European Marine Energy Centre), we have seen a variety of devices with different options and solutions, some of which share elements with our invention. This is why we believe it is important to highlight the differences between them. First, we will look at those classified as "closed venturi." These devices are characterized by a funnel-shaped cover or casing that narrows, encloses, confines, and concentrates the flow. The water is directed into a turbine with a propeller of slightly smaller diameter than the tube that guides the flow. Downstream of the constriction, the cover's diameter widens slightly to improve discharge efficiency based on the Venturi effect. This list includes variations in the shape of the casing and the turbine itself, as well as in the method of transferring the water's kinetic energy to the rotor that drives the generator with different types of propellers.

[0004] The proposed invention differs from these devices in three fundamental ways. The first difference is the use of a second, external venturi that provides the driving flow and functions as an ejector pump (independent of the flow within the turbine connected to the generator). The flow captured by Venturi #2 provides additional energy by converting the turbine's discharge head into a pressure gradient with the mixing chamber, thereby promoting fluid movement. This difference is noteworthy because all of the listed devices are limited by the Betz limit on the percentage of kinetic energy the turbine can utilize from the flow acting on its rotor. Each turbine requires sufficient kinetic energy in the discharge flow to expel the fluid. In the present invention, two venturis work together, and the kinetic energy of the discharge acting on the turbine is increased by the pressure difference with the mixing chamber, created by the ejector pump with an external driving flow corresponding to Venturi #2. The energy limitation of the turbine of the present invention relative to the flow of the first venturi is cavitation, and a significant amount of pressure energy can be utilized corresponding to the depth at which the turbine is located. The energy balance for expelling the two flows is based on total kinetic energy and also obeys the Betz limit. This difference is important because the thrust generated by the flow in the secondary venturi significantly increases the energy and power output of the turbine relative to the flow acting on the rotor and its blades. The cost of building an ejector pump (external secondary venturi) is significantly lower than building a turbine that captures an equivalent amount of energy directly from the flow through its blades.

[0005] This is the second difference in the present invention. Namely, the inventors have considered using a flexible membrane to construct the hopper cover or casing that confines water during the intake and discharge intervals in a Venturi tube (the contraction and expansion intervals of the hydraulic cross section). This membrane maintains its shape by adapting to internal and external pressure fluctuations using tension. The third difference is the addition of a cross-flow turbine M1 (revolving door type, two-bladed) for generating electricity from marine hydrokinetic energy. None of these three elements, separately or in combination, are present in any of the listed proposals.

[0006] The second group of EMEC devices includes those called "horizontal axis turbines" and "vertical axis turbines." Within these two groups, there are turbine options that can utilize a complementary ejector pump (with a motive flow) using parts of the present invention. In fact, many of these turbines can be significantly improved in efficiency by complementing them with an ejector pump (an external second venturi) that allows for increased energy conversion to hydraulic head. This condition increases the power generation level at low cost. None of these devices incorporate the first two elements included in the present invention. Furthermore, the present invention incorporates a cross-flow turbine M1 (revolving door type, two-bladed) with a double vertical axis. It must operate housed in a casing, as shown in Figures 2, 3, 4, and 5 (pages 25 and 26). Its operation is proposed to utilize the kinetic energy of ocean currents and also works with a motive flow to increase its power output (see Figure 1-A, page 23). Furthermore, it has unique characteristics not shared with any other turbines.

[0007] The crossflow turbine M1, shown in Figures 2, 3, 4, and 5 (pages 25 and 26), operates entirely confined within a geometry formed by joining two semi-cylinders with an axis of symmetry about the junction at the center of the flow. The blades between the rotors are spaced a distance "S" apart (see Figure 5, page 26). The drawings suggest six blades on each rotor, oriented toward the flow concentration zone and discharging to an ejector pump to increase the turbine's discharge energy (see Figure 1-A). This underwater turbine operates by utilizing the pressure difference between the turbine discharge and a mixing chamber to discharge the treated flow (ejector pump, venturi #2). These elements are not present in any other turbines that utilize the kinetic energy of ocean currents.

[0008] e) In order to highlight the importance of the areas where the device of the present invention will be located and developed, reference is made to the "Text approved by the European Parliament" of Wednesday 16 February 2022, entitled "European Strategy for Offshore Renewable Energy", in which Preamble "R" states: "The implementation of offshore renewable energy will depend on the efforts of public and private entities, but public entities may also work together with private entities in the offshore renewable energy sector, and amendments to state aid and public procurement rules should provide greater flexibility in implementing the green transition, including for offshore renewable energy projects." [Brief explanation of the drawings]

[0009] [Figure 1-A] FIG. 1-A shows a basic schematic of the present invention, consisting of two Venturi tubes. [Figure 1-B] FIG. 1B shows a schematic diagram of a comparative example of the present invention. [Figure 1-C] FIG. 1-C shows a different arrangement of the "Marine Turbine for Kinetic and Potential Energy" than FIG. 1-A. [Figure 1-D] FIG. 1-D shows a third embodiment of the invention having two turbines and a central ejector pump that creates a mixing chamber for both turbines. [Figure 2] FIG. 2 shows a basic embodiment of the M1 turbine (revolving door type, two blades, two vertical axes) in plan view. [Figure 3] FIG. 3 shows section A-A' in a front view of the turbine, showing the spacing Y1 corresponding to the placement of the diaphragm to stabilize the turbine shaft when the turbine shaft is at a certain length. [Figure 4] FIG. 4 corresponds to the longitudinal section B-B' of the turbine. [Figure 5] FIG. 5 defines some of the most important geometric characteristics of the turbine shown in FIG. [Figure 6] FIG. 6 shows a front view of the intake hopper of Venturi #1 and #2, which is composed of a flexible membrane held in tension and resembles an impermeable fishing net. [Figure 7] FIG. 7 shows a longitudinal cross section of a configuration using flexible membranes in both the intake and discharge hoppers. [Figure 8] FIG. 8 shows details of the rotor blades. Detailed Description of the Invention

[0010] "Marine Turbine for Utilizing Kinetic and Potential Energy" is the title of this invention and refers to a set of elements that make up an apparatus or device for utilizing the kinetic energy of ocean currents, seas, or estuaries by transferring the kinetic energy of the water to a turbine that drives a generator. The device consists of two main parts: A) an intake and ejector pump with a mixing chamber, and B) a cross-flow turbine M1 (revolving door type, two blades).

[0011] A) Intake and ejector pump with mixing chamber A.1.: General description of intake and ejector pumps with mixing chambers:

[0012] The present invention is presented as a Venturi tube with two independent inlets, one for the process stream and the other for the drive stream of the ejector pump (see Figure 7, page 27). The figure shows a filling hopper (5) designated Venturi #1 and a second hopper (6-a) for the ejector pump (1) of Venturi #2. Both inlet hoppers are joined to a rigid ring in the area designated the mixing chamber (2) and share a common outlet for both streams with a Venturi tube shape, designated the discharge hopper (6-b). The first inlet is designated Venturi #1 for the stream, and the second inlet is designated Venturi #2 for the hydraulic head (ejector pump). These two inlets have a Venturi tube shape that concentrates the kinetic energy of the larger hydraulic cross section by reducing the cross section and increasing the fluid velocity. Venturi #1 (flow) has an extreme constriction downstream and terminates in a turbine (4) connected to the mixing chamber (2) via a pipe (3). The turbine discharge generates a hydraulic gradient that is converted into a head, driven by the transfer of kinetic energy from the water entering through Venturi #2. In the "mixing chamber," the flows from the filling hoppers corresponding to Venturi #1 and #2 join.

[0013] The concept of this invention is to take advantage of the relatively stable flow velocity (kinetic energy) of ocean currents and the ability to capture this energy (potential energy) at significant depths. This invention introduces the idea of ​​using a second venturi #2 with a mixing chamber at a pressure lower than the pressure at the turbine outlet, creating a hydraulic gradient between the turbine and the mixing chamber to move the fluid. While the total available energy from the two flows is limited by the Betz limit, it is possible to use an ejector pump to transfer some of the energy from venturi #2 to the turbine in venturi #1 and use this increased energy to drive the turbine. By generating lower pressure in the mixing chamber, a significant proportion of the existing potential energy can be utilized due to the depth at which the turbine is located. The condition is that the flow entering venturi #2 is much greater than the process flow, allowing for a significant increase in available power in the turbine via the hydraulic gradient to the mixing chamber.

[0014] The pressure in the mixing chamber is designed using Venturi #2 to utilize most of the pressure head generated by the depth at which the turbine of Venturi #1 is located. A hydraulic gradient is generated through the ejector pump (Venturi #2) to drive the turbine discharge flow. If the turbine were to operate solely on kinetic energy transferred directly to the rotor, it would be limited by the amount of energy required to maintain motion at the discharge (Betts coefficient limit). Furthermore, the amount of energy depends on the diameter or hydraulic cross-section captured by the blades. The present invention solves this problem by using an ejector pump, because the power generated through the pressure gradient at the discharge can be significantly increased, ensuring that the fluid, along with the entire treatment flow, has enough energy to reach the mixing chamber. Furthermore, a second venturi with a much larger flow rate can discharge the entire flow from both venturis into the ocean. To prevent cavitation, a positive pressure higher than the water vapor pressure in the mixing chamber is maintained. The limit for increasing the hydraulic head through the ejector pump in this invention is the sum of atmospheric pressure and the hydraulic head at the depth at which the turbine is located, minus losses. This allows the risk of cavitation to be controlled if the flow rate increase is within the available net suction head (NPSH).

[0015] The device of the present invention incorporates a second flow from an ejector pump, which adds kinetic energy to the turbine and converts it into hydraulic head. The ejector pump, constructed from a flexible membrane (the second element of the present invention), provides an additional level of pressure head at very low construction costs. The advantage of the present invention in harnessing the kinetic energy of ocean currents lies in how this energy is transferred to the turbine rotor. Propeller rotors require large blades and very stiff turbines to transfer the kinetic energy of the water directly to the machine shaft. In contrast, with an ejector pump, the kinetic energy is converted into pressure energy, which is then utilized by a turbine with a smaller propeller diameter via a pressure gradient.

[0016] A.2. Flexible membrane forming a Venturi hopper:

[0017] In this invention, the intake and discharge hoppers of the Venturi tube are flexible membranes that adjust their shape to fluctuations in internal and external pressure. They can be made using impermeable fishing nets held in place by tension bodies connected to stationary points (e.g., the seabed or a floating buoy in the same mooring or fixed position; see page 27). In the case of Venturi #2 (ejector pump), the hoppers formed by the flexible membrane are adjusted between a rigid ring in the mixing chamber and the end of a tension body moored to the seabed or a buoy. In the case of Venturi #1, the pipe (3) has a flange at the end, and the other end of the membrane is similarly tensioned against a fixed support that serves as an anchor. By fixing the end of the tension body, the entire kinetic energy of the ocean current can be utilized, and the membrane's shape adapts to fluctuations in internal and external pressure.

[0018] Considering a fluid moving through a Venturi tube, we observe that at the intake, the hydraulic cross section decreases and the fluid velocity increases with decreasing internal pressure. At the discharge, the hydraulic cross section increases, the flow velocity decreases, and the pressure increases. In the intake hopper of the present invention, which has a very flexible tube, the internal pressure decreases, causing it to collapse under constant external pressure. If it were rigid, it would deform and be subjected to compressive stress due to the pressure difference. This invention proposes a tube made of a flexible membrane with a collapse limiter via a tie rod. In this case, the pressure difference is transmitted to the tension element as a tensile stress that is resisted like a circus tent cover. At the discharge hopper, the internal pressure reverses, rising from a minimum to the far end until the internal and external pressures are equal, a situation that is also supported by the tension element.

[0019] A.3. Comparative Example to Explain the Importance of the Invention Based on Hydroelectric Power Plant Construction Experience: (See Figure 1-B, page 23)

[0020] In hydroelectric power plant design, the present invention uses the term "head height Ho" (defined as the elevation difference between the turbine shaft and the water level in the load tank). In the present invention, the change in kinetic energy in the charging hopper of Venturi #1 is defined as D5(V 2 ) / (2g). We now consider a turbine submerged at a depth of Z1 meter, and assume that it removes almost all the water at the outlet while maintaining a value Hd at the turbine outlet (corresponding to the pressure head that protects against cavitation and subsequent losses after the turbine to prevent fluid stoppage).

[0021] In this case, the available head height Ho = Z1 - Hd + D5(V 2 ) / (2g). In this invention, the Ho value gives the available head height to generate mechanical energy that can be converted into electricity. If the head loss at the intake of the hopper (5) is "SDh1" and the available head height is "He", then He = Ho - SDh1 (and this is the head height available for the turbine). This is the importance of the ejector pump. The ejector pump creates a pressure difference at the turbine outlet, allowing the turbine to utilize potential energy based on the depth at which it is located.

[0022] At the turbine outlet, the pressure head Hd (8) is obtained, which is a function of the following factors: Hd = Pc / (rg) + SDh2 + (Z2 - Z1) + D3V 2 / (2g)+A

[0023] where: Pc / (rg): pressure head in the mixing chamber SDh2: Head loss due to energy losses between the turbine outlet and the mixing chamber Z2-Z1: Height difference between the mixing chamber and the turbine outlet D3V 2 / (2g): Change in kinetic energy in the pipe between the turbine and the mixing chamber A: Variables and head height parameters that protect against cavitation in the turbine and convert kinetic energy into potential energy (providing a safety factor)

[0024] A.4. Equipment design factors:

[0025] The device of the present invention consists of two intake hoppers, each with its own independent flow. Its design depends on the relationship between the process flow and the ejector pump flow (driving flow). Using basic fluid equations in a mathematical or physical scale model, the device's operating losses can be determined and the transferable pressure head for a specific process flow and the corresponding device can be obtained. To implement the project, the depth and flow velocity conditions of the ocean current must be known, the flow and head height that meet the demand must be defined, and a location must be selected. Using the defined output and process flow, the geometry and material with the corresponding roughness are determined, and the losses in the intake hoppers and discharge to the mixing chamber are experimentally established using a scale model. The pressure difference between the turbine and the mixing chamber is adjusted. This data can be used to design the ejector pump, its hydraulic cross section, flow, and shape. Considering the magnitude of the flow in the ocean current and the depth at which these devices can be installed, the possibilities are enormous.

[0026] In the present invention, the power load ratio is defined as follows: Rp = ejector pump flow rate / treatment flow rate. The key variable to define is the relationship between the hydraulic cross section Ac of the mixing chamber ring with the corresponding pressure and the hydraulic cross section At of the turbine discharge pipe. The Ac / At ratio can be used to adjust the pressure difference between the turbine discharge and the working pressure of the mixing chamber. Through mathematical analysis, the Rp value can be defined and adjusted to a parameter that achieves high efficiency and ensures turbine output without cavitation.

[0027] In designing flexible membranes, the internal and external pressure differences for various possible load conditions are considered. The magnitude of the action on the membrane and its stresses are determined. The internal and external pressure variations can be obtained from the basic fluid equations and their interaction with ocean currents, following aerodynamic principles for different boundary conditions.

[0028] A.6. Basic Design Variations:

[0029] In the first part of this document, "Intake and Ejector Pump with Mixing Chamber," the present invention is shown in an arrangement corresponding to FIG. 1-A. However, the elements of the intake and ejector pump with mixing chamber of the present invention can also be presented in different arrangements. As a second example, a flow venturi is placed inside the ejector pump, as shown in FIG. 1-C. As a third example, the possibility of developing multiple intake hoppers with a large central venturi is presented (see FIG. 1-D, page 24).

[0030] B. Crossflow turbine M1 (revolving door type, two blades)

[0031] B.1. Turbine Overview:

[0032] The inlet with a mixing chamber and ejector pump of the present invention can operate independently or can be added to many existing commercial or experimental turbines, significantly improving their efficiency. The cross-flow turbine M1 (revolving door type, two-blade) is designed to operate solely by harnessing the kinetic energy of ocean currents, but has many other possibilities. This turbine is a horizontal or vertical axis cross-flow turbine that can operate in large flows, is easy to manufacture, and is adjustable to low to moderate head heights. The M1 turbine is loaded through a Venturi #1 tube and is thought to operate only in fully confined conditions. Its casing is configured by joining two semi-cylinders with axes of symmetry about the junction at the center of the flow. The turbine has a rotor with blades (6 to 8 vanes) oriented toward the flow concentration zone and an outlet to an ejector pump to increase the turbine's ejection energy. The submersible turbine is connected to an ejector pump, which generates a pressure differential between the turbine outlet and the mixing chamber to eject the treated flow. Ejector pumps harness the kinetic energy of ocean currents, estuaries, or waterways for their operation. The ejector pump includes detailed geometries and components shown in Figures 2, 3, 4, and 5 (pages 25 and 26). Figure 5 shows a plan view of a crossflow turbine (with two vertical or horizontal axes) of the present invention, while Figure 3 shows a front cross-section and Figure 4 shows a longitudinal cross-section. In Figure 5, some of the most important geometric characteristics are defined (radius, blade size and break angle, flow concentrating wedge, and the distance "S" between the blades on the two rotor shafts). For its design, requirements are defined, and its parameters are adjusted based on the results obtained for "S" experimentally adjusted on a scale prototype. The rotor blade radius is assumed based on the manufacturer's equipment capabilities. Once this value is adjusted, the turbine dimensions and characteristics are specified.

[0033] 5. Detailed description of the drawings: Figure 1-A shows a basic schematic diagram of the present invention, consisting of two venturi tubes. Venturi #1 for the flow with an intake hopper captures the process flow. Venturi #2 is an ejector pump that generates a pressure in the mixing chamber that is lower than the pressure at the turbine outlet. The turbine and mixing chamber are connected via a pipe. The pressure in the mixing chamber is positive and must be higher than the water vapor pressure with a safety margin, considering all practical flow configurations.

[0034] FIG. 1B shows a schematic diagram of a comparative example of the present invention at the end of the description, where the value Ho=Z1−Hd+D5V 2 Produces a turbine available head having a value of / 2g, where: Z1 corresponds to the depth of the turbine. D5V 2 / 2g: Change in kinetic energy at the intake Hd: Head height at turbine outlet in pipe Effective head height: He where He = Ho-SDh1 SDh1: Head loss at the intake of the hopper (5)

[0035] Figure 1-C, at the end of the description, shows a different arrangement of the "Marine Turbine for Kinetic and Potential Energy" than Figure 1-A. In this case, Venturi #1 is inside Venturi #2, a rigid ring houses the turbine outlet, and the two flows meet in a mixing chamber. This configuration is more compact than the previous one.

[0036] Figure 1-D shows a third embodiment of the invention with two turbines and a central ejector pump that creates a mixing chamber for both turbines. This embodiment shows the flexibility of the arrangement or solution for the device of the invention. In fact, many operating solutions exist based on the core idea.

[0037] Figure 6, page 27, shows a front view of the intake hoppers of Venturi #1 and #2, which consist of a flexible membrane held in tension, resembling an impermeable fishing net. The tension body captures and supports stresses, maintaining its shape to prevent collapse due to pressure differences between the inside and outside. Therefore, the inner end is attached to a central rigid ring, and on the outside, the tension body is secured with anchors to the seabed or similarly to a moored buoy. In this case, the mixing chamber is located inside the rigid ring of Venturi #2, as is Venturi #1, which terminates in a rigid ring housing the turbine.

[0038] Figure 2, page 25, shows a plan view of the basic embodiment of the M1 turbine (revolving door type, two blades, two vertical shafts). Figure 3 shows the section A-A' in a front view of the turbine, showing the distance Y1 corresponding to the placement of the diaphragms for stabilizing the turbine shaft when the turbine shaft is at a certain length. The blades have reinforcing ribs on their periphery where the openings for the turbine shaft stabilization diaphragms are located.

[0039] Figure 4 corresponds to the longitudinal cross section B-B' of the turbine at the end of the description. Its outlet is also shown, and Figure 5 defines some of its most important geometric characteristics (radius, blade size and break angle, flow concentration wedge, and the distance "S" between the blades on the two rotor shafts). The "S" value defined for the turbine is experimentally adjusted using a scale prototype. The rotor blade radius is assumed based on the manufacturer's equipment capabilities. Once that value is adjusted, the turbine's dimensions and characteristics are defined.

[0040] Two variants of the M1 turbine are available, one with six vanes and one with eight vanes. Figure 8 shows a detailed view of the rotor blades.

[0041] Figure 6, at the end of the description, shows a front view of the device with venturis #1 and #2, which tension the membrane and the central location of the turbine and mixing chamber.

[0042] Finally, FIG. 7 shows a longitudinal cross section of a configuration using flexible membranes in both the intake and discharge hoppers.

Claims

1. A product consisting of an apparatus for harnessing the kinetic energy of ocean currents and converting it into mechanical energy, comprising an external ejector pump (1) with a flow independent of the process flow, the external ejector pump (1) comprising a Venturi #2 tube with a filling hopper (6-a) for the driving flow, a central rigid ring containing a mixing chamber (2), a discharge hopper (6-b) and a cross-flow turbine.

2. 1. Product according to claim 1, characterized in that the central rigid ring containing the mixing chamber (2) is connected via a pipe (3) to the outlet of a turbine (4), which is driven by the flow entering another filling hopper (5) of the venturi #1 (see Fig. 1-A).

3. The product according to claim 2, characterized in that the mixing chamber (2) into which the two filling hoppers of Venturi #1 (5) and Venturi #2 (6-a) discharge has a common discharge hopper, which is the discharge hopper (6-b) (see Fig. 1-A).

4. 4. The product according to claim 3, characterized in that the ejector pump (1) has a pressure Pc in the central zone of the mixing chamber (2) that is lower than the pressure present at the turbine outlet (4) and has a head height Hd (8) at the turbine outlet.

5. 5. Product according to claim 4, characterized in that the rigid ring of the mixing chamber is located at a depth Z2(7-B), and the pressure Pc of the mixing chamber is obtained by changing the pressure in the filling hopper of the ejector pump through a reduction in the hydraulic cross section in the filling hopper of the ejector pump, and the flow rate is increased by the Venturi effect of the ejector pump.

6. 6. The product of claim 5, wherein the value of Hd(8) is positive and greater than the head height corresponding to the pressure Pc in the mixing chamber and the increase in flow rate is within the available positive net suction head (NPSHd) in compliance with the cavitation control parameters.

7. 10. The product of claim 6, characterized in that it utilizes impermeable flexible membranes (10), (11), (12) (see Figure 7) held in tension by tension bodies to form the intake (6-a), (5) and discharge (6-b) hoppers of the venturi.

8. 8. Product according to claim 7, characterized in that the flexible membrane adapts its shape to the pressure difference between the inside and outside of the terminal hopper of the Venturi tube, and the membrane tensioner limits its deformation and transmits the stress to a buoy (15) or a fixed point or anchor (14) on the seabed.

9. 9. Product according to claim 8, characterized in that it is a cross-flow turbine M1 (15) (revolving door type, two blades) for generating electricity from marine hydrokinetic energy (MHK) with a horizontal or vertical axis (16) (see Figures 2, 3, 4 and 5).

10. 9. A product according to claim 9, characterized in that the elements of the cross-flow turbine M1 (15) are two rotors (16) with six or eight blades (17), the turbine intake has a hydraulic cross-section constriction for concentrating the flow, constituted by flow concentrating wedges (18) with the shape shown in FIG. 5, deflected by 15° to each side of the flow, the casing (19) has an aerodynamic shape with curvatures that start and end tangentially to the discharge pipe and the turbine casing, to confine and redirect the flow, and the rotor vanes (20) have details of six and eight vanes (see FIG. 8).

11. Product according to claim 10, characterized by the possibility of operating the elements constituting the turbine in combination or independently, together with the ejector pump (1) and any turbine, the cross-flow turbine M1 (15) (revolving door type, two-blade), without the option of a flexible membrane or a rigid hopper, with the option of keeping the ends of the hoppers stationary using tethered tension bodies or relative movement devices for fixing the movements of the venturi filling and discharging hoppers, and the different possible arrangements (see figures 1-C and 1-D).

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