Externally or passively driven flow device for liquid or gaseous media, including an axially flowable impeller supported in a housing, and use of such a flow device

Abstract

An externally or passively driven flow device for liquid or gaseous media is described, which comprises a housing in which an impeller through which axial flow is arranged. The impeller can be rotated by an external drive or by the medium. The impeller has a ring body with blades, which is supported on its outer periphery in the housing and has an axial central flow passage. A swirling motion combined with a pressure gradient rising from the outer periphery toward the axial central flow passage of the impeller is applied to the medium.

Description

[Technical Field]

[0001] The present invention relates to an externally driven or passively driven flow device for liquid or gaseous media of the type defined in the preamble of claim 1, as well as to the use of such a flow device according to claims 11 to 14. [Background technology]

[0002] The externally driven flow device may be, for example, in the form of a fan for pumping a gaseous medium. The fan has an impeller that rotates in a housing and allows axial or radial flow. In fluid engineering, these are called axial or radial fans. The present invention relates to a flow device with an impeller that is supported in a housing and allows axial flow. The impeller consists of a ring body with blades.

[0003] German Patent Application Publication No. 102007032423 discloses a fan as a flow device that can be considered the closest prior art. As already described in German Patent Application Publication No. 102007032423, the known axial fan has the disadvantage that the impeller blades are connected to one another radially outward by an impeller or rotor ring body and radially inward to a wheel hub, which is supported in a fixed bearing by a bearing shaft. Central support of the impeller is disadvantageous in an axial fan because the wheel hub blocks a large central cross-sectional area of ​​the impeller. As a result, the entrained air that strikes the wheel hub in the axial direction is first deflected radially outward and then accelerated again by the rotating blades and directed further in the desired pumping direction.

[0004] DE 10 2007 032 423 A1 proposes to solve this problem by supporting the impeller in a contactless manner on a stationary housing element of the fan: the impeller is held in suspension by magnetic forces, and the repulsive forces between like poles of the permanent magnets are used for axial and radial centering of the impeller.

[0005] German Patent Application Publication No. 102007032423 proposes a central opening axially symmetrical with respect to the central axis of rotation, through which the injected airflow passes during fan operation. The airflow generated by a fan constructed in accordance with German Patent Application Publication No. 102007032423 consists of a peripheral flow generated by the rotating blades and a central jet flow resulting from the pressure gradient between the outlet and inlet sides of the axial fan. The flow inside the central jet corresponds to a laminar flow rather than a turbulent peripheral region. As the distance from the fan impeller or outlet nozzle increases, the initially laminar core flow becomes turbulent in the central region of the overall airflow due to the interaction of the partial airflows in the transition region. By appropriately selecting the ratio of the inside cross-sectional area of ​​the central impeller opening to the ring-disk-shaped inside area within which the blades rotate, fans with various outlet characteristics can be realized. Summary of the Invention [Problem to be solved by the invention]

[0006] The object of the present invention is to improve a flow device of the type mentioned at the outset so that a relatively high volume flow rate of the flowing medium can be achieved. [Means for solving the problem]

[0007] This problem is solved by the features of claim 1 in an externally driven or passively driven flow device according to the preamble of claim 1.

[0008] Developments and advantageous configurations are set forth in the dependent claims.

[0009] The present invention relates to an externally or passively driven flow machine for liquid or gaseous media. When the medium is externally driven, an impeller with blades sucks the medium, accelerates it, and pushes it out to an outlet area. An external drive, such as an electric motor or turbine, rotates the impeller. The impeller blades, by their rotation, exert a circulating force on the medium, which causes a whirling motion. The whirling motion is the rotation of the medium around the axis of the impeller, which increases the kinetic energy of the medium.

[0010] Furthermore, the shape of the impeller blades pushes the medium from the periphery towards the center of the impeller, creating a pressure gradient, which is the difference in static pressure of the medium between the periphery and the axial center channel of the impeller, thereby increasing the potential energy of the medium.

[0011] The medium flows through the impeller both through the ring-shaped region where the impeller blades are located and through the axial central flow section, where the medium attains a higher velocity and pressure than before entering the impeller, allowing for a higher volumetric flow.

[0012] The realization underlying the present invention is that when a bottle completely filled with water is rotated with the opening downwards, an additional rotational motion is created, causing the water to flow out of the bottle at a slower rate than would flow out of a bottle in which a vortex is formed in the water. This vortex creates a continuous, faster dynamic movement of the water flowing out of the bottle. In other words, when a vortex is created, the bottle empties at a significantly higher rate. A flow device according to the present invention, such as a fan, accelerates a medium by rotating an impeller so strongly that a vortex is created.

[0013] An important prerequisite for optimal vortex flow is that the rotating medium can flow unimpeded through the flow path. In the present invention, this is achieved by eliminating the central hub present in conventional flow devices. To utilize the suction force generated by vortices, stable and powerful vortex flow formation is necessary. The flow dynamics in vortex flow are the most stable structure and least sensitive to disturbances from the surrounding medium. In flow devices that include obstacles to the free fluid flow, the medium flow is initially turbulent and vortex-like. Orderly rotation of the flow is not possible at first. Obstacles or disturbances can prevent the formation of vortices. Stable vortex flow only breaks down later. Breakdown does not occur inside the flow; the vortex propagates inward from the periphery.

[0014] In this case, the surrounding medium is forced to mix with the accelerated medium in the vortex flow based on the laws of physics, particularly the Coanda effect and Bernoulli's principle. The surrounding medium is gradually braked by the formation of complex vortices, which make it wider and quieter. The flow resulting from the stable vortex flow lasts longer and allows for a larger pumping volume with the same energy consumption. The stable and highly pronounced vortex flow generates a suction force that extends forward into the flowing medium, i.e., against the flow direction, and through or upstream of the rotating blades of the impeller or rotor of the flow device.

[0015] This effect occurs when draining water from a bathtub. Not only does it suck water from the bottom through the outlet, but it also creates a suction force that sucks water from the surface. The rotation of the water is already generated by the vortexes that form before it reaches the outlet. This also applies to the flow device described in this invention. The medium is already rotated and accelerated before it comes into contact with the impeller blades. This reduces energy consumption, since the suction effect only occurs when the vortexes are sufficiently stable.

[0016] The same applies to passively driven flow devices, i.e., media-driven flow devices, as described for externally driven flow devices.

[0017] The impeller blades preferably have a curvature and / or tilt position that differs from the axis of rotation of the impeller.

[0018] This feature affects the power output and efficiency of the flow device, and the manner in which this feature functions is explained below.

[0019] The curvature of an impeller blade describes the blade's deviation from a straight line. The curvature can be convex or concave, depending on whether the blade is bent outward or inward. The curvature of the blade affects the shape and size of the flow passage between the blades through which the medium flows. A larger curvature narrows the flow passage and increases the flow velocity. A smaller curvature widens the flow passage and decreases the flow velocity. The optimal curvature of the blade depends on the type and purpose of the flow device. A larger curvature may be advantageous for a pump that is to generate high pressure. Conversely, a smaller curvature may be advantageous for a turbine that is to generate high power.

[0020] The tilt position of an impeller blade represents the angle between the blade and the impeller's axis of rotation. The tilt position can be positive or negative, depending on whether the blade is tilted in the direction of rotation of the impeller or against the direction of rotation. The tilt position affects the direction and magnitude of the force exerted on the medium. A positive tilt position increases the rotational force component and the swirling motion of the medium, while a negative tilt position reduces both. The optimal blade tilt position depends on the type and purpose of the flow device. A positive tilt position may be advantageous for a pump that must generate high pressure. In contrast, a negative tilt position may be advantageous for a turbine that must generate high power.

[0021] The impeller blades may have a sickle or shovel shape.

[0022] The impeller is formed in a sickle or shovel shape to pump the medium through the impeller more efficiently and quietly. In this case, flow losses are minimized and flow quality is optimized. The aerodynamic characteristics of the impeller are improved by reducing air resistance and improving flow control. The sickle or shovel shape can increase the power and efficiency of the flow device by matching the rotation speed and pressure of the medium.

[0023] A sickle or shovel shape is a deviation from a straight line, which may be convex or concave, that affects the shape and size of the passage between the blades through which the media flows. A larger sickle or shovel shape narrows the passage and increases the flow velocity. A smaller sickle or shovel shape widens the passage and decreases the flow velocity.

[0024] The optimum sickle or shovel shape will depend on the type and purpose of the flow device, for example a larger sickle or shovel shape may be advantageous for a pump that is to generate high pressure, whereas a smaller sickle or shovel shape may be advantageous for a turbine that is to generate high power output.

[0025] The inclination of the impeller blades preferably decreases from the outside to the inside. The inclination of an impeller blade is defined as the theoretical distance that the blade would travel in one revolution in an axial medium if it were assumed to rotate in a solid material, like a threaded block. If the inclination is linear, all areas of the impeller blade will contribute equally to the forward movement from the outside to the inside. In contrast, if the inclination decreases, the outer areas will contribute more to the forward movement than the inner areas.

[0026] The tilt therefore affects the direction and magnitude of the force that the impeller blades exert on the media.

[0027] Reduced tilt means that the impeller blades are flatter in the direction of the axial flow passage in the center of the impeller. As a result, the blades exert a smaller force component on the medium in the rotational direction and a larger force component in the axial direction. This causes the medium to accelerate more strongly in the center.

[0028] The function of decreasing slope is to minimize flow losses and optimize flow quality. Flow losses are energy losses due to friction, turbulence, or shock waves. Flow quality is the uniformity and stability of the flow. Decreasing slope can reduce flow losses by reducing friction between the media and the blades and avoiding turbulence and shock waves that can occur at high speeds. Decreasing slope can improve flow quality by allowing the flow to conform to the impeller shape and preventing flow separation that can lead to instability.

[0029] In addition to the shape and orientation of the impeller blades, adaptation and optimization of the number, distribution, and size of the impeller blades is feasible and can be advantageous.

[0030] Such matching and optimization leads to impeller blades that optimally pump the media through the impeller, minimizing flow losses and maximizing efficiency. The number, distribution and size of impeller blades are important factors that determine the properties of the impeller, such as flow resistance, flow guidance, noise generation and power transfer.

[0031] The impeller vane count is the number of blades attached to the impeller ring. The number of impeller blades affects the size and shape of the flow passages between the blades through which the medium flows. A larger number of blades reduces the flow passage and increases the flow velocity, while a smaller number of blades increases the flow passage and decreases the flow velocity. The optimal number of impeller blades depends on the type and purpose of the flow restrictor. For example, a larger number of blades may be advantageous for a pump that must generate high pressure, while a smaller number of blades may be advantageous for a turbine that must generate high power.

[0032] Impeller blade distribution is the arrangement of blades on the impeller ring. Impeller blade distribution affects the uniformity and stability of the flow through the impeller. A uniform distribution of impeller blades results in a symmetrical and stable flow, whereas a non-uniform distribution of impeller blades can lead to an asymmetrical and unstable flow. The optimal impeller blade distribution depends on the type and purpose of the flow device. For example, a uniform distribution of impeller blades may be advantageous for a pump or turbine that requires high reliability and safety, whereas a non-uniform distribution of impeller blades may be advantageous for a flow machine that is to generate a predetermined flow profile.

[0033] Impeller blade dimensions are the size and shape of the blades, which can be described by various parameters such as length, width, thickness, curvature, tilt, and inclination. Impeller blade dimensions affect the aerodynamic properties of the blades, such as air resistance, flow control, noise generation, and power transmission. Larger impeller blade dimensions increase the surface area and volume of the blades, while smaller impeller blade dimensions decrease the surface area and volume of the blades. The optimal impeller blade dimensions depend on the type and purpose of the flow device. For example, larger impeller dimensions may be advantageous for pumps that must generate high pressure, while smaller impeller dimensions may be advantageous for turbines that must generate high power.

[0034] Matching and optimizing the number, distribution, and size of impeller blades is a complex and multi-layered problem that requires a variety of mathematical models, numerical methods, and experimental methods. Matching and optimization can vary depending on the requirements of the flow system and the surrounding conditions.

[0035] Furthermore, the housing may have an inlet, the diameter of which in the region of the impeller blades corresponds to the diameter of the impeller blades themselves.

[0036] If the housing has an inlet whose diameter in the region of the impeller blades corresponds to the diameter of the blades themselves, the medium will be pumped by the impeller at a lower speed and higher pressure. This minimizes flow losses and maximizes efficiency. The inlet is the opening through which the medium enters the housing. The diameter of the inlet affects the flow velocity and static pressure of the medium before it enters the impeller.

[0037] The same diameter means that the inlet has the same cross section as the area of ​​the impeller blades, so that the medium has a constant velocity and a constant pressure before it reaches the impeller, i.e., it is not accelerated as much and compressed as much.

[0038] The functionality of the same diameter is to minimize flow losses and maximize efficiency. Flow losses occur due to friction, turbulence, or shock waves, leading to energy loss. Efficiency represents the ratio of energy released to energy absorbed. A diameter that remains the same can reduce flow losses by reducing friction between the media and the housing and avoiding turbulence and shock wave formation at high speeds. Furthermore, a diameter that remains the same can increase efficiency by improving energy transfer between the media and the impeller.

[0039] The inlet is preferably tapered in a funnel shape to match the diameter of the impeller blades.

[0040] By tapering like a funnel, we mean that the inlet has a larger cross section than the area of ​​the impeller blades and narrows in the direction of the impeller, so that the medium has a lower velocity and a higher pressure before it reaches the impeller.

[0041] The function of the funnel tapering is to minimize flow losses and maximize efficiency. Flow losses are the energy lost due to friction, turbulence, or shock waves. Efficiency is the ratio of energy released to energy absorbed. Funnel tapering reduces flow losses by reducing friction between the media and the housing and avoiding turbulence and shock waves that can occur at high speeds. Funnel tapering increases efficiency by improving energy transfer between the media and the impeller.

[0042] The functionality of the funnel taper depends on the type and purpose of the flow device: a funnel taper may be advantageous for pumps that are to generate high pressure, for example, whereas a uniform or expanding diameter may be advantageous for turbines that are to generate high power.

[0043] Furthermore, the inlet may have a flow guiding unit formed as a spiral and / or a diffuser.

[0044] The flow guiding unit in the form of a spiral or diffuser influences the flow direction of the medium and contributes to the formation of vortices, which in turn leads to high stability of the vortices formed and high efficiency and power output.

[0045] The rotor of the motor is driven by a ring-shaped impeller, while the stator is surrounded by a housing.

[0046] The flow device can be operated by a directly driven electric motor, which is a special type of electric motor that is directly coupled to the impeller without a gearing.

[0047] Direct drive electric motors convert electrical energy into mechanical energy by generating a rotating magnetic field that drives a rotor. There are various types of direct drive electric motors, such as asynchronous motors, stepper motors, or permanent magnet synchronous motors. Direct drive electric motors have the advantages of high rotational speed, high efficiency, high precision, and low noise generation.

[0048] The rotor is the rotatable part of the electric motor and consists of a ring-shaped impeller with blades. The rotating magnetic field of the stator sets the rotor in motion.

[0049] The stator is the stationary part of an electric motor and consists of a housing that surrounds the rotor. The stator generates the rotating magnetic field that drives the rotor. The stator consists of multiple coils and a soft iron core attached to the housing.

[0050] Direct drive electric motors allow for direct power transmission between the stator and rotor. By eliminating transmissions, friction losses, play, maintenance and noise generation are reduced. This leads to high efficiency, reliability and safety of the flow system.

[0051] According to a further development, the ring-shaped impeller can be supported in the housing in a floating manner by magnetic forces.

[0052] By magnetically supporting the ring-shaped impeller in a floating manner within the housing, mechanical losses are minimized and service life is maximized. Magnetic force is the force acting between magnets or between a magnet and a magnetizable material. Magnetic force can be attractive or repulsive depending on the orientation of the magnetic poles.

[0053] By floating support, we mean that the impeller is held in a stable position by a magnetic field without direct contact with the housing. The impeller is rotated by an external drive, such as an electric motor or a turbine, which causes a swirling motion and a pressure gradient in the medium flowing through it.

[0054] The floating support has the function of eliminating friction between the impeller and the housing, which would otherwise lead to mechanical losses, wear, noise generation and heat generation. The floating support increases the efficiency, reliability and safety of the flow device.

[0055] The floating support can be achieved by various types of magnetic bearings, such as passive, active, or hybrid magnetic bearings. Passive magnetic bearings stabilize the impeller using attractive or repulsive forces between permanent magnets or between permanent magnets and superconductors. Active magnetic bearings stabilize the impeller using adjustable forces between electromagnets and magnetizable material. Hybrid magnetic bearings combine passive and active magnetic bearings to utilize the benefits of both systems.

[0056] Distributing the impeller's mass more to the outer area than in a central hub design results in higher rotational energy and a stronger gyroscopic effect, which increases the impeller's directional stability, which can also be used for drone flight stabilization. The gyroscopic effect is the inertia of a rotating body against changes in the direction of its axis of rotation.

[0057] Furthermore, the present invention relates to the use of externally driven flow devices, with potential uses as fans, as screws or propellers for boats and ships, and as jet engines.

[0058] The flow device, which can be used as a fan or as a replacement for conventional screws or propellers on boats and ships, can be made extremely flat and therefore lightweight and space-saving.

[0059] In the case of use in a jet engine, if blades that are not supported by a hub are used according to the invention, that is, if an impeller is used with blades that allow or guarantee a flow in the center while forming a strong and stable vortex, the power output of the jet engine can be increased accordingly by the vortex formed according to the invention.

[0060] The invention will now be described with reference to an illustrative embodiment. [Brief explanation of the drawings]

[0061] [Figure 1] 1 is a perspective view of a conventional flow device consisting of an impeller with blades attached to a hub. [Figure 2] 2 is a longitudinal axial section of the flow device shown in FIG. 1 in a static state. [Figure 3] 2 is an axial longitudinal section of the flow device shown in FIG. 1 with a simulation of the flowing medium. [Figure 4] 1 shows a perspective view of a flow device according to the invention consisting of an impeller with a central opening; [Figure 5] 5 is a longitudinal axial section through the flow device shown in FIG. 4 in a static state. [Figure 6] 5 is an axial longitudinal section of the flow device shown in FIG. 4 with a simulation of the flowing medium. [Figure 7] FIG. 1 shows a schematic diagram of a ring-shaped permanent magnet as part of a housing for supporting an impeller. [Figure 8] FIG. 8 is a schematic cross-sectional view of the permanent magnet of FIG. 7 described above. [Figure 9] FIG. 1 shows a permanent magnet structure that is wider on the inside than on the outside. [Figure 10] FIG. 1 is a plan view showing an impeller with permanent magnets arranged at an angle of 120° from each other. [Figure 11] FIG. 11 is a side view of the impeller shown in FIG. 10, seen from a position rotated 90°. [Figure 12]FIG. 1 is a front view showing a schematic diagram of an impeller with two blades. [Figure 13] FIG. 13 is a cross-sectional view schematically showing the impeller shown in FIG. 12. [Figure 14] 1 is a schematic diagram of a fan with an impeller and a coil of an electromagnet attached to the impeller. DETAILED DESCRIPTION OF THE INVENTION

[0062] The figures show various configurations of the flow device.

[0063] FIG. 1 shows a perspective view of a conventional flow device consisting of an impeller 10 with blades 12 mounted on a hub 14. The impeller blades 12 of the flow device have a linear slope. The slope of the impeller blades 12 represents the distance the impeller blades 12 travel in an axial direction parallel to the impeller axis 16 per revolution. With a linear slope, the blade angle of the impeller blades 12 increases continuously and proportionally from the root of the blade 12 at the center to the outer tip. The blade angle represents the angle the impeller blades 12 make with respect to the axis of rotation 16 of the impeller 10 at each radial position.

[0064] Figure 2 shows an axial longitudinal section of the flow device shown in Figure 1 in a static state as a preliminary step to the simulation. The impeller blades 12 and the central hub 14 to which the impeller blades 12 are attached are visible.

[0065] Figure 3 shows an axial longitudinal section of the flow device shown in Figure 1, along with a simulation of the flowing medium. In this case, the hub 14 and impeller blades 12 are shown forcing the flowing medium 18 to diverge outward downstream of the impeller 10. In this configuration, no central vortex can occur.

[0066] 4 shows a perspective view of a flow device according to the present invention, which comprises an impeller 20 with blades 22 attached to an outer ring 24. There is no central hub. Instead, the impeller 20 has a central opening 26. The flow device impeller blades 22 do not have a linear slope. Rather, the blade angle of the impeller blades 22 increases less than proportionally from the edge of the central opening 26 to their outer tips.

[0067] Figure 5 shows an axial longitudinal section of the flow device shown in Figure 4 in a static state as a preliminary step to the simulation. The impeller blades 22 and the central opening 26 are visible.

[0068] Figure 6 shows an axial longitudinal section of the flow device shown in Figure 4, together with a simulation of the flowing medium 28. In this case, the flowing medium 28 is shown to be deflected and condensed towards the center downstream of the impeller 20. As the flow moves away from the impeller 20, the streamlines become more condensed and form a core 30. Here, stable vortices are created, which contribute to increasing the flow rate of the medium 28.

[0069] 7 to 14 show a flow device in the form of a fan. The fan comprises an impeller supported by permanent magnets, the impeller having a ring body with a central flow passage. This fan is a lightweight flow device capable of generating stable vortex flows. A further advantage is that the fan can be made very flat. This is made possible by arranging the drive device as a stator around the impeller as a rotor. The stator is positioned radially outwardly around the rotor, so to speak. It is not necessary to arrange the drive device axially upstream or downstream of the impeller with its blades.

[0070] FIG. 7 shows an annular permanent magnet 32 ​​for supporting the impeller. FIG. 8 shows a cross section of the permanent magnet 32 ​​around the impeller. The permanent magnet reduces the frictional resistance of the impeller. The concave shape of the ring-shaped permanent magnet 32 ​​on the inner surface serves to guide the impeller, which is held in a floating manner inside the ring-shaped permanent magnet 32. The permanent magnet can also be called a retaining ring. Additional ring-shaped permanent magnets may be provided. For lighter fan embodiments, one ring-shaped permanent magnet 32 ​​is already sufficient. At higher rotational speeds of the flow device, e.g., the fan impeller, multiple ring-shaped permanent magnets can reinforce or ensure secure holding and stability, especially in heavier, more powerful embodiments.

[0071] The flow device may have an integral outer support ring for supporting the impeller or rotor, which does not function as a drive.

[0072] If the impeller 34 or rotor is driven by a bipolar outer stator, this outer ring may advantageously be constructed from two separate half rings 36, 38, as shown in Figure 9. This allows the different polarities of the two magnetic poles to be utilized separately from each other.

[0073] In the latter case, the rotor is ideally configured with at least three permanent magnets 40, 42, and 44, as shown in Figure 10. These permanent magnets are spaced 120° apart from one another and therefore rotate based on the changing polarity of the stator.

[0074] 10 and 11 show a structure with permanent magnets 40, 42, 44 which are wider on the inside than on the outside to prevent displacement of the supported permanent magnets under centrifugal force.

[0075] Higher power flow devices require a rotor with a coil in which a current is induced, a technology already known in various electric motors, whether DC or AC motors and / or synchronous or asynchronous motors.

[0076] The impeller 34 or rotor is ideally also supported by permanent magnets 40, 42, 44 to provide stable, low-friction guidance. FIG. 12 shows a front view of the impeller 34 or rotor, with only two blades 46, 48 shown for clarity. The definition of the shape of the impeller blades is arbitrary in this case. The shape and orientation of the impeller blades, as well as their dimensions and distribution, may differ from those shown in the drawings to generate stable, powerful vortices. It is not necessary, as shown in FIG. 13, for the impeller blades 46, 48 to have a relatively small cross-section in the forward region at the entry of the airflow and gradually expand as the airflow progresses.

[0077] 14 shows a fan with an impeller 34 and coils 50, 52 as components of an electromagnet. The coils 50, 52 are connected to the impeller 34 to form a rotating unit. According to the invention, the center 54 of the impeller 34, and thus of the flow device, remains open, thereby ensuring space for vortices or eddies that become stronger and more powerfully formed at higher impeller rotation speeds.

[0078] The fan inlet is wider to pump a steady and powerful air flow. A similar principle is known in nozzle drives. [Explanation of symbols]

[0079] 10 impeller 12 Impeller blades 14 Hub 16 Rotation axis 18 Medium 20 impeller 22 Impeller blades 24 ring body 26 Aperture 28 Medium 30 cores 32 Permanent magnets 34 Impeller 36 Half Ring 38 Half Ring 40 Permanent Magnets 42 Permanent magnets 44 Permanent Magnets 46 Impeller blades 48 Impeller blades 50 coils 52 Coil 54 center

Claims

1. 1. An externally or passively driven flow device for a liquid or gaseous medium, comprising a housing in which an axially flowable impeller is arranged, said impeller being rotatable by an external drive or by said medium, said impeller having a ring body with blades, said ring body being supported in said housing on its outer periphery and having an axial central flow passage, 10. A flow device capable of imparting a swirling motion to the medium combined with a pressure gradient increasing from the outer periphery toward the axial center passage of the impeller.

2. 2. The flow device of claim 1, wherein the impeller blades have a curved and / or tilted position different from the axis of rotation of the impeller.

3. 3. A flow device according to claim 1 or 2, characterized in that the impeller blades have a sickle or shovel shape.

4. 4. A flow device according to claim 1, wherein the inclination of the impeller blades decreases from the outside to the inside.

5. 5. The flow device according to claim 1, wherein in addition to the shape and orientation of the impeller blades, the number, distribution and size of the impeller blades can be adapted and optimized.

6. 6. A flow device according to claim 1, wherein the housing has an inlet, the diameter of which in the region of the impeller blades corresponds to the diameter of the impeller blades themselves.

7. 7. A flow device according to any one of claims 1 to 6, characterized in that the inlet is tapered in a funnel shape to match the diameter of the impeller blades.

8. 8. The flow device according to claim 1, wherein the inlet has a flow guiding unit configured as a spiral and / or a diffuser.

9. 9. The flow device according to claim 1, wherein the external drive device comprises a directly driven electric motor, the rotor of which is formed by a ring-shaped impeller and the stator of which is formed by a housing surrounding the rotor.

10. 10. A flow device according to any one of claims 1 to 9, characterized in that the ring-shaped impeller is supported in the housing in a floating manner by magnetic forces.

11. Use of an externally driven flow device according to any one of claims 1 to 10 as a fan.

12. Use of an externally driven flow device according to any one of claims 1 to 10 as a screw or propeller for boats and ships.

13. Use of an externally driven flow device according to any one of claims 1 to 10 as a jet engine.

14. Use of a passively driven flow device according to any one of claims 1 to 8 or claim 10 as an electric generator.

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