Flow device, which is externally or passively powered, for a liquid or gaseous medium, comprising an impeller which is mounted in a housing and through which the medium can flow in the axial direction, and use of such a flow device

Abstract

The invention relates to a flow device, which is externally or passively powered, for a liquid or gaseous medium, consisting of a housing that is equipped with an impeller through which the medium can flow in the axial direction. The impeller can be rotated by an external drive or by the medium, wherein the impeller comprises an annular body with impeller vanes, said annular body being supported in the housing on the outer circumference of the annular body and having an axially central passage. A swirl combined with a pressure gradient which increases from the outer circumference to the axially central passage of the impeller is applied to the medium.

Description

[0001] Externally or passively driven flow device for a liquid or gaseous medium, comprising an axially flowable impeller mounted in a housing, and use of such a flow device

[0002] The invention relates to an externally or passively driven flow device for a liquid or gaseous medium according to the preamble of claim 1 and the use of such a flow device according to claims 11-14

[0003] An externally driven flow device can, for example, be in the form of a fan that conveys a gaseous medium. The fan has an impeller with axial or radial flow that rotates in the housing. In fluid mechanics, these are referred to as axial or radial fans. The present invention relates to flow devices with an impeller with axial flow that is mounted in a housing. The impeller consists of an annular body with impeller blades.

[0004] DE 10 2007 032 423 A1 describes fans as flow devices that can be considered the closest prior art. As already described in DE 10 2007 032 423 A1, known axial fans have the disadvantage that the impeller blades, which are connected to each other radially on the outside by the annular body of the impeller or rotor, are connected radially on the inside to a wheel hub that is mounted in fixed bearings by means of a bearing shaft. In axial fans, the central bearing of the impeller is disadvantageous because the wheel hub shades a large central cross-sectional area of ​​the wheel. As a result, entrained air that strikes the wheel hub axially is first deflected radially outwards before being accelerated again by the rotating impeller blades and forwarded in the desired conveying direction.

[0005] DE 10 2007 032 423 A1 proposes solving this problem by mounting the impeller non-contacting on stationary fan housing elements. The impeller is held suspended by magnetic forces, and the repulsive forces between like-pole permanent magnets are used to axially and radially center the impeller.

[0006] According to DE 10 2007 032 423, it is proposed that a central opening be provided through which an injection air jet flows during ventilation operation and which is axially symmetrical with respect to the central axis of rotation. The air flow generated by a fan designed according to DE 10 2007 032 423 consists of a bypass flow generated by the rotating wheel blades and a central injection flow created by the pressure gradient between the outlet and upstream sides of the axial fan. The flow within the central injection flow is more like a laminar flow than in the turbulent jacket region. With increasing distance from the impeller or an outlet nozzle of the fan, turbulence in the initially laminar core flow occurs in the central region of the overall air flow due to the interaction of the partial air flows in the transition region.By appropriately selecting the ratio of the clear cross-sectional areas of the central wheel opening and the annular disc-shaped clear area within which the wheel blades rotate, fans with different outlet characteristics can be realized.

[0007] The invention is based on the object of improving a flow device of the type mentioned above such that a comparatively higher volume flow of the flowing medium can be achieved. This object is achieved in an externally or passively driven flow device according to the preamble of claim 1 by the features of this claim.

[0008] Further developments and advantageous embodiments arise from the subclaims.

[0009] The invention relates to an externally or passively driven turbomachine for a liquid or gaseous medium. With an externally driven medium, an impeller with blades draws in the medium, accelerates it, and pushes it into the outlet area. The external drive, for example, an electric motor or a turbine, causes the impeller to rotate. The rotation of the impeller's blades generates a circulating force on the medium, creating a swirl. Swirl is a rotational movement of the medium around the impeller's axis, which increases the medium's kinetic energy.

[0010] Additionally, the shape of the impeller's blades forces the fluid from its outer periphery toward its center, creating a pressure gradient. This pressure gradient is a difference in the fluid's static pressure between the outer periphery and the axial central passage of the impeller, which increases the fluid's potential energy.

[0011] The fluid flows through the impeller, both through the annular area occupied by the impeller blades and through the axial central passage. The impeller imparts a higher velocity and pressure to the fluid than before entering the impeller, enabling a high flow rate.

[0012] The invention is based on the discovery that water flows more slowly from a fully filled bottle when it is turned upside down than from a bottle that is additionally set in a rotating motion, which creates a vortex in the water. This vortex leads to a dynamic and sustained, faster movement of the water flow from the bottle. When a vortex is created, the bottle empties much faster. The flow device according to the invention, such as a fan, accelerates the medium so strongly through the rotation of the impeller that a vortex forms.

[0013] An important prerequisite for an optimal vortex is that the rotating medium can flow unhindered through the flow path. In the present invention, this is achieved by omitting a central scar, as is present in conventional flow devices. In order to utilize the suction created by the vortex, the formation of a stable and powerful vortex is required. The flow dynamics in a vortex are the most stable structure and the least susceptible to disturbances from the surrounding medium. In flow devices that contain obstacles to the free flow of flow, the flow of the medium is subject to disturbances and turbulence from the outset. An orderly rotation of the flow never occurs at all. Obstacles or disturbances can prevent the formation of a vortex. A stable vortex only dissipates later.The decomposition does not take place within the flow, but the vortex spreads from the edge inwards.

[0014] The surrounding medium inevitably mixes with the accelerated medium in the vortex due to the laws of physics, particularly the Coanda effect and Bernoulli's principle. The surrounding medium is gradually slowed down by complex turbulence, becoming wider and calmer. A flow originating from a stable vortex is longer-lasting and allows for a larger pumped volume with the same energy consumption. A stable and strongly pronounced vortex creates a suction that extends forward into the flowing medium, i.e., against the flow direction, and through or in front of the rotating impeller blades of the impeller or rotor of the flow device.

[0015] This effect occurs when draining water from a bathtub. A suction is created that not only draws water from the lower layers through the outlet, but also sucks it in from the surface. The rotation of the water is already initiated by the forming vortex before it hits the outlet. This also applies to the flow device described in this invention. The medium is already set in rotation and accelerated before it comes into contact with the impeller blades. This results in lower energy requirements, since the suction effect only occurs when the vortex is stable.

[0016] The statements made regarding externally driven flow devices apply analogously to a passively driven flow device, i.e. a flow device that is driven by the medium.

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

[0018] These features influence the performance and efficiency of the flow device. The functioning of these features can be explained as follows:

[0019] The curvature of the impeller blades describes the deviation of the blades from a straight line. The curvature can be either convex or concave, depending on whether the blades are bent outwards or inwards. The curvature of the blades influences the shape and size of the flow channel between the blades through which the medium flows. A larger curvature narrows the flow channel and increases the flow velocity. A smaller curvature widens the flow channel and reduces the flow velocity. The optimal curvature of the blades depends on the type and purpose of the flow device. A larger curvature may be advantageous for a pump designed to generate high pressure. A smaller curvature, on the other hand, may be advantageous for a turbine designed to generate high power.

[0020] The inclination of the impeller blades describes the angle between the blades and the impeller's axis of rotation. Depending on whether the blades are inclined in or against the direction of impeller rotation, the inclination can be either positive or negative. The inclination influences the direction and strength of the force exerted on the medium. A positive inclination increases the force component in the direction of rotation and the swirl of the medium, while a negative inclination reduces both. The optimal inclination of the blades depends on the type and purpose of the flow device. A positive inclination may be advantageous for a pump that needs to generate high pressure. A negative inclination, on the other hand, may be advantageous for a turbine that needs to generate high power.

[0021] The impeller blades can have a sickle or blade shape.

[0022] The impeller blades are designed in a sickle or vane shape to move the fluid through the impeller more efficiently and quietly. This minimizes flow losses and optimizes flow quality. The aerodynamic properties of the blades are improved by reducing drag and increasing flow control. The sickle or vane shape can increase the performance and efficiency of the flow device by adjusting the speed and pressure of the fluid.

[0023] It is a deviation from a straight line, which can be either convex or concave, and influences the shape and size of the flow channel between the blades through which the medium flows. A larger sickle or blade shape narrows the flow channel and increases the flow velocity. A smaller sickle or blade shape widens the flow channel and decreases the flow velocity.

[0024] The optimal sickle or blade shape depends on the type and purpose of the flow device. For example, a larger sickle or blade shape may be advantageous for a pump designed to generate high pressure, while a smaller sickle or blade shape may be advantageous for a turbine designed to generate high power.

[0025] The pitch of the impeller blades decreases preferentially from the outside to the inside. The pitch of the impeller blades is defined as the theoretical distance the impeller blade would travel in one revolution in an axial medium if it were rotating in a solid material such as a threaded block. If the pitch were linear, all areas of the impeller blades would contribute equally to propulsion from the outside to the inside. With a depressed pitch, however, the outer areas would contribute more to propulsion than the inner areas.

[0026] The pitch influences the direction and magnitude of the force that the impeller blades exert on the medium.

[0027] A decreasing pitch means that the impeller blades become flatter towards the central axial passage of the impeller. This results in the blades exerting a smaller force component on the fluid in the direction of rotation and a larger force component in the axial direction. This accelerates the fluid more strongly in the center. The function of the decreasing pitch 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. A decreasing gradient can reduce flow losses by reducing the friction between the fluid and the blades and avoiding turbulence and shock waves that can occur at high speeds.A decreasing pitch can improve flow quality by adapting the flow to the shape of the impeller and preventing flow separation that can lead to instabilities.

[0028] In addition to the shape and orientation of the impeller blades, adjusting and optimizing the number, distribution and dimensioning of the impeller blades may be feasible and advantageous.

[0029] This adaptation and optimization ensures that the impeller blades optimally convey the medium through the impeller, minimizing flow losses and maximizing efficiency. The number, distribution, and dimensioning of the impeller blades are important factors that determine the impeller's properties, such as flow resistance, flow guidance, noise generation, and power transmission.

[0030] The impeller blade count is the number of vanes attached to the impeller ring. The number of impeller vanes influences the size and shape of the flow channel between the vanes through which the medium flows. A larger number of impeller vanes reduces the flow channel and increases the flow velocity, while a smaller number of impeller vanes enlarges the flow channel and decreases the flow velocity. The optimal number of impeller vanes depends on the type and purpose of the flow restrictor. For example, a larger number of impeller vanes may be advantageous for a pump designed to generate high pressure, while a smaller number of impeller vanes may be advantageous for a turbine designed to generate high power.

[0031] The impeller blade distribution is the arrangement of the blades on the impeller ring. The distribution of the impeller blades influences the uniformity and stability of the flow through the impeller. A uniform distribution of the impeller blades results in symmetrical and stable flow, while an uneven distribution of the impeller blades can lead to asymmetrical and unstable flow. The optimal distribution of the impeller blades depends on the type and purpose of the flow device. For example, a uniform distribution of the impeller blades may be advantageous for a pump or turbine, which requires high reliability and safety, whereas an uneven distribution of the impeller blades may be advantageous for a turbomachine, which is designed to generate a specific flow pattern.

[0032] Impeller blade sizing refers to the size and shape of the blades, which can be described by various parameters such as length, width, thickness, curvature, inclination, and pitch. Impeller blade sizing affects the aerodynamic properties of the blades, such as drag, flow control, noise generation, and power transmission. Larger impeller blade sizing increases the surface area and volume of the blades, while smaller impeller blade sizing decreases the surface area and volume of the blades. The optimal impeller blade sizing depends on the type and purpose of the flow device. For example, a larger impeller sizing may be advantageous for a pump designed to generate high pressure, while a smaller impeller sizing may be advantageous for a turbine designed to generate high power.Adapting and optimizing the number, distribution, and dimensions of impeller blades is a complex and multifaceted problem that requires various mathematical models, numerical methods, and experimental procedures. The adaptation and optimization can vary depending on the requirements and boundary conditions of the flow system.

[0033] In addition, the housing may have an inlet whose diameter in the area of ​​the impeller blades corresponds to the diameter of the impeller blades themselves.

[0034] If the casing has an inlet whose diameter in the area of ​​the impeller blades corresponds to the diameter of the impeller blades themselves, the fluid is conveyed through the impeller at a lower velocity and higher pressure. This minimizes flow losses and maximizes efficiency. The inlet is the opening through which the fluid enters the casing. The diameter of the inlet influences the flow velocity and static pressure of the fluid before it enters the impeller.

[0035] A uniform diameter means that the inlet has the same cross-section as the impeller blade area. This results in the fluid having a constant velocity and pressure before reaching the impeller. The fluid is therefore accelerated and compressed less.

[0036] The function of a constant diameter is to minimize flow losses and maximize efficiency. Flow losses arise from friction, turbulence, or shock waves and lead to energy loss. Efficiency describes the ratio between the energy delivered and the energy absorbed. A constant diameter can reduce flow losses by reducing friction between the medium and the casing and preventing turbulence and shock wave formation at high speeds. Furthermore, a constant diameter can increase efficiency by improving the energy transfer between the medium and the impeller.

[0037] The inlet should taper in a funnel shape to the diameter of the impeller blades.

[0038] A funnel-shaped taper means that the inlet has a larger cross-section than the impeller blade area and tapers towards the impeller. This results in a lower fluid velocity and higher fluid pressure before reaching the impeller.

[0039] The function of the funnel-shaped taper is to minimize flow losses and maximize efficiency. Flow losses are the energy lost through friction, turbulence, or shock waves. Efficiency is the ratio between the energy delivered and the energy absorbed. A funnel-shaped taper can reduce flow losses by reducing friction between the fluid and the casing and avoiding the turbulence and shock wave formation that can occur at high speeds. A funnel-shaped taper can increase efficiency by improving the energy transfer between the fluid and the impeller.

[0040] The function of the funnel-shaped taper depends on the type and purpose of the flow device. For example, a funnel-shaped taper may be advantageous for a pump designed to generate high pressure, while a uniform or expanded diameter may be advantageous for a turbine designed to generate high power.

[0041] Furthermore, the inlet can have a flow guide configured as a spiral and / or a diffuser. A flow guide in the form of a spiral or a diffuser can help influence the flow direction of the medium and stimulate vortex formation. This can result in greater stability of the formed vortex and higher efficiency and performance.

[0042] The rotor of the motor is driven by the annular impeller, while the stator is surrounded by the housing.

[0043] The flow device can be operated with a direct-drive electric motor. The electric motor is a special type that is directly connected to the impeller without a gearbox.

[0044] The direct drive electric motor converts electrical energy into mechanical energy by generating a rotating magnetic field that drives the rotor. There are various designs of direct drive electric motors, such as asynchronous motors, stepper motors, or permanent magnet synchronous motors. The direct drive electric motor has the advantages of high speed, high efficiency, high precision, and low noise.

[0045] The rotor is the rotating 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.

[0046] The stator is the fixed part of the electric motor and consists of a housing that surrounds the rotor. The stator generates the rotating magnetic field that drives the rotor. It consists of several coils and soft iron cores attached to the housing. The direct drive electric motor enables direct power transmission between the stator and the rotor. By eliminating the gearbox, friction losses, backlash, maintenance, and noise are reduced. This leads to greater efficiency, reliability, and safety of the flow device.

[0047] According to a further development, the annular impeller can be suspended in the housing by magnetic forces.

[0048] By suspending the annular impeller in the housing using magnetic forces, mechanical losses are minimized and service life is maximized. Magnetic forces are forces acting between magnets or between magnets and magnetizable materials. They can be either attractive or repulsive, depending on the orientation of the magnetic poles.

[0049] The floating bearing design means that the impeller is held in a stable position by a magnetic field, without direct contact with the casing. It is rotated by an external drive, such as an electric motor or turbine. This causes the impeller to generate a swirl and a pressure gradient on the fluid flowing through the impeller.

[0050] The floating bearing eliminates friction between the impeller and the housing. This friction would otherwise lead to mechanical losses, wear, noise, and heat generation.

[0051] The floating bearing increases the efficiency, reliability and safety of the flow device.

[0052] Floating bearings can be achieved using various types of magnetic bearings, such as passive, active, or hybrid magnetic bearings. Passive magnetic bearings utilize the attractive or repulsive forces between permanent magnets or between permanent magnets and superconductors to stabilize the impeller. Active magnetic bearings, on the other hand, utilize controllable forces between electromagnets and magnetizable materials to stabilize the impeller. Hybrid magnetic bearings combine passive and active magnetic bearings to utilize the advantages of both systems.

[0053] By distributing the mass of the impeller more toward the outer area compared to designs with a central hub, higher rotational energy and a stronger gyroscopic effect are generated, increasing the directional stability of the impeller. This can also be used for flight stabilization of drones. A gyroscopic effect is the inertia of a rotating body with respect to changes in the direction of its rotation axis.

[0054] The invention further relates to the use of an externally driven flow device. Possible uses include a fan, a screw or propeller for boats and ships, and a jet engine.

[0055] The flow device, which can be used as a fan or as a replacement for conventional screws and propellers of boats and ships, can be designed to be very flat and thus lightweight and space-saving.

[0056] When used as a jet engine, its performance could be increased by a vortex designed accordingly according to the invention if impeller blades not mounted by means of a hub were used according to the invention, i.e. an impeller with impeller blades that allows or ensures a flow in the center with the formation of a strong and stable vortex.

[0057] The invention will now be explained with reference to an embodiment shown in the drawing, in which: Fig. 1 shows a perspective view of a conventional flow device comprising an impeller with impeller blades mounted on a hub,

[0058] Fig. 2 shows an axial longitudinal section of the flow device according to Fig. 1 in the rest state,

[0059] Fig. 3 shows an axial longitudinal section of the flow device according to Fig. 1 with a simulation of a flowing medium,

[0060] Fig. 4 shows a perspective view of a flow device according to the invention comprising an impeller with a central opening,

[0061] Fig. 5 shows an axial longitudinal section of the flow device according to Fig. 4 in the rest state,

[0062] Fig. 6 shows an axial longitudinal section of the flow device according to Fig. 4 with a simulation of a flowing medium,

[0063] Fig. 7 shows schematically a ring-shaped permanent magnet as part of the housing for supporting an impeller,

[0064] Fig. 8 shows schematically a cross section through the aforementioned permanent magnet according to Fig. 7,

[0065] Fig. 9 shows a construction with permanent magnets that are wider inside than outside, Fig. 10 shows a top view of an impeller with permanent magnets that are arranged at an angle of 120° to each other,

[0066] Fig. 11 shows the impeller according to Fig. 10 from a position rotated by 90° in side view,

[0067] Fig. 12 shows a schematic front view of the impeller with two impeller blades,

[0068] Fig. 13 shows schematically the impeller according to Fig. 12 in cross section and

[0069] Fig. 14 shows a schematic diagram of a fan with an impeller and coils of an electromagnet attached to it.

[0070] The drawing shows different designs of flow devices.

[0071] Fig. 1 shows a perspective view of a conventional flow device consisting of an impeller 10 with impeller blades 12 mounted on a hub 14. The impeller blades 12 of the flow device have a linear pitch. The pitch of an impeller blade 12 describes the distance that the impeller blade 12 travels per revolution in the axial direction parallel to the impeller axis 16. With a linear pitch, the blade angle of the impeller blades 12 increases continuously and proportionally from the base of the impeller blades 12 in the center to the outer tip. The blade angle describes the angle that the impeller blade 12 forms at the respective radial position to the rotational axis 16 of the impeller.

[0072] Fig. 2 shows an axial longitudinal section of the flow device according to Fig. 1 in the resting state as a preliminary stage to a simulation. The impeller blades 12 and the central hub 14, to which the impeller blades 12 are attached, are visible. Fig. 3 shows an axial longitudinal section of the flow device according to Fig. 1 with a simulation of a flowing medium. It can be seen that both the hub 14 and the impeller blades 12 spread the flowing medium 18 outward behind the impeller 10. A central vortex cannot develop in this design.

[0073] Fig. 4 shows a perspective view of a flow device according to the invention, consisting of an impeller 20 with impeller blades 22 attached to an outer annular body 24. There is no central hub. Instead, the impeller 20 has an opening 26 in the center. The impeller blades 22 of the flow device do not have a linear pitch. Rather, the blade angle of the impeller blades 22 increases disproportionately from the edge of the central opening 26 to the outer tip.

[0074] Fig. 5 shows an axial longitudinal section of the flow device according to Fig. 4 in the resting state as a preliminary stage to a simulation. The impeller blades 22 and the central opening 26 are visible.

[0075] Fig. 6 shows an axial longitudinal section of the flow device according to Fig. 4 with a simulation of a flowing medium 28. It can be seen that the flowing medium 28 is directed toward the center behind the impeller 20 and compressed. At a distance from the impeller 20, the flow lines are also compressed into a core 30. This creates a stable vortex that contributes to increasing the throughput of the medium 28.

[0076] Figures 7 to 14 show a flow device in the form of a fan. This comprises an impeller mounted by permanent magnets, which has a ring body with a central passage. The fan is a lightweight flow device in which a stable vortex can form. A further advantage is that the fan can be designed very flat. This is made possible by positioning the drive as a stator around the impeller as a rotor. The stator is positioned radially around the outside of the rotor. It is not necessary to arrange a drive axially in front of or behind the impeller with the impeller blades.

[0077] 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 annular permanent magnet 32 ​​on the inside serves to guide the impeller, which is held suspended within the annular permanent magnet 32. The permanent magnet can also be referred to as a holding ring. Additional annular permanent magnets can be provided. For a lighter version of the fan, one annular permanent magnet 32 ​​is sufficient. Several annular permanent magnets reinforce or ensure the secure hold and stability at higher speeds of the impeller or impellers, especially in heavier and more powerful versions of the flow devices such as fans.

[0078] The flow device may have a one-piece outer bearing ring for supporting the impeller or rotor, which does not perform any drive function.

[0079] If the impeller 34 or the rotor is driven by a bipolar outer stator, this outer ring can advantageously be constructed from two separate half rings 36, 38, as shown in Fig. 9. This makes it possible to utilize the different charges of the two poles separately.

[0080] In the latter case, the rotor should ideally be constructed with at least three permanent magnets 40, 42, 44, as shown in Fig. 10. These are arranged at 120° to each other and are thus set in rotation due to the changing polarity of the stator.

[0081] Fig. 10 and 11 show a construction with permanent magnets 40, 42, 44 which are wider on the inside than on the outside in order to prevent displacement of the mounted permanent magnets under centrifugal forces.

[0082] More powerful flow devices require a rotor with current-induced coils. This technology is already known in various electric motors, regardless of whether they are DC or AC and / or synchronous or asynchronous.

[0083] The impeller 34 or the rotor is ideally also mounted using permanent magnets 40, 42, 44 to enable stable and low-friction guidance. Fig. 12 shows a front view of the impeller 34 or rotor, whereby for the sake of clarity only two impeller blades 46, 48 are shown. The determination of the impeller blade shape is arbitrary here. The shape and orientation as well as the dimensions and distribution of the impeller blades can deviate from the impeller blades shown in order to generate a stable and strong vortex. It is not absolutely necessary to design the impeller blades 46, 48 with a less profiled front area at the inlet of the air flow, as shown in Fig. 13, and to make them increasingly larger as the air flow progresses.

[0084] Fig. 14 shows the fan with impeller 34 and coils 50, 52 as components of electromagnets. The coils 50, 52 are connected to the impeller 34 and form a rotating unit. According to the invention, the center 54 of the impeller 34, and thus of the flow device, remains open to ensure space for the vortex or eddy, which forms even stronger and more intensely at higher impeller speeds. The fan inlet is wider to promote a stable and powerful airflow. A similar principle is known in jet propulsion.

[0085] List of reference symbols

[0086] 10 Wheel

[0087] 12 impeller blades

[0088] 14 Hub

[0089] 16 Rotation axis

[0090] 18 Medium

[0091] 20 wheel

[0092] 22 impeller blades

[0093] 24 ring bodies

[0094] 26 Opening

[0095] 28 Medium

[0096] 30 core

[0097] 32 permanent magnet

[0098] 34 wheel

[0099] 36 half ring

[0100] 38 half ring

[0101] 40 permanent magnet

[0102] 42 permanent magnet

[0103] 44 permanent magnet

[0104] 46 impeller blades

[0105] 48 impeller blades

[0106] 50 spool

[0107] 52 coil

[0108] 54 Center

Claims

Patent claims 1 . Externally or passively driven flow device for a liquid or gaseous medium, consisting of a housing in which an impeller is arranged through which axial flow can be made and which can be set in rotation by an external drive or by the medium, wherein the impeller comprises an annular body with impeller blades which is mounted on its outer circumference in the housing and has an axial central passage, characterized in that a swirl combined with a pressure gradient increasing from the outer circumference to the axial central passage of the impeller can be impressed on the medium.

2. Flow device according to claim 1, characterized in that the impeller blades have a curvature and / or an inclined position which deviates from the axis of rotation of the impeller.

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

4. Flow device according to one of claims 1-3, characterized in that the pitch of the impeller blades decreases from the outside to the inside 5. Flow device according to one of claims 1-4, characterized in that in addition to the shape and orientation of the impeller blades, an adaptation and optimization of the number, distribution and dimensions of the impeller blades can be carried out.

6. Flow device according to one of claims 1-5, characterized in that the housing has an inlet whose diameter in the region of the impeller blades corresponds to the diameter of the impeller blades themselves.

7. Flow device according to one of claims 1-6, characterized in that the inlet tapers in a funnel shape to the diameter of the impeller blades.

8. Flow device according to one of claims 1-7, characterized in that the inlet has a flow guide which is designed as a spiral and / or as a diffuser.

9. Flow device according to one of claims 1-8, characterized in that in the case of an external drive, this consists of a directly driven electric motor, the rotor of which is formed by the annular impeller and the stator of which is formed by the housing surrounding the rotor.

10. Flow device according to one of claims 1-9, characterized in that the annular impeller is suspended in the housing by magnetic forces.

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

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

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

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

Images