WO2014079847A1

WO2014079847A1 - Pump arrangement

Info

Publication number: WO2014079847A1
Application number: PCT/EP2013/074179
Authority: WO
Inventors: Bernhard Vodermayer; Heinrich Gmeiner
Original assignee: Deutsches Zentrum für Luft- und Raumfahrt e.V.
Priority date: 2012-11-22
Filing date: 2013-11-19
Publication date: 2014-05-30
Also published as: DE102012221358B3

Abstract

A pump arrangement has two separately drivable rotor elements (10, 12), each having conveying elements (14, 16). The conveying elements (14, 16) form conveying surfaces (18, 22). Depending on the position of the conveying elements relative to one another, different conveying surfaces (18, 22) are active, and therefore the flow direction of the conveyed medium can be changed, while the rotational direction of the rotor elements remains constant, by changing the position of the conveying elements (14, 16) relative to one another.

Description

Pumpyorrichtung

The invention relates to a particular electro-fluid pumping device.

Such pumping devices have to convey fluids, i. Liquids and / or gases rotor elements on.

Hydraulic drive systems for a reversing pumping operation have predominantly arrangements which operate with a constant direction of rotation and set the conveying direction of the pumping medium via control valves. Depending on the pressure environment, the valve systems are more or less complex and cumbersome. Due to safety requirements, valve technology in industrial plants requires power even when they are not moving. A high energy consumption of the entire facility is the result. This method also has the disadvantage that enormous pressure surges can arise through the opening and closing of the valves, which greatly reduces the life of all parts present in the hydraulic circuit. In particular, this relates to the valve and line technology as well as the pump itself. All components involved must be more robust and thus designed to be larger and heavier. Furthermore, the number of installed parts also increases.

JP63-192995 discloses, for example, a vane pump, wherein the conveying direction by changing the direction of rotation of the rotor and additionally a valve technology takes place. This leads to poor efficiency and high mechanical wear of the parts.

Furthermore, pumps are known which change the direction of rotation to realize a change in the conveying direction. For example, propulsion systems for submarine or aeronautical applications, ie submarines or zeppelins, which require turbines or propellers for locomotion or maneuvering are to be mentioned here. Submarine applications are often based on injection applications, which are similar in design and function to a reversing axial flow pump.

Reversing pump systems have the major disadvantage that they have to change the direction of rotation in order to achieve the reversal of the conveying direction. Especially in systems which are used for maneuvering nautical vehicles or, for example, in medical technology for generating a pulsatile volume flow, a reversing operation considerably limits the service life, since the bearing is loaded much more heavily than in a drive with a constant direction of rotation. In marine or submarine applications, therefore, one often deviates from a swiveling drive, which, however, in turn entails considerable additional mechanical effort and thus a higher risk of failure.

Another major disadvantage of reversing the direction of rotation in displacement or flow pumps are enormous signs of wear on all mechanically moving parts, in particular on parts which are in contact with the fluid. This situation further contributes to the reduction of the service life.

Furthermore, in the prior art, redundancy can only be created by the parallel construction of multiple arrays, which means that the overall systems must be large in size to minimize the risk of failure. Furthermore, arrangements are known which set the conveying direction of the working medium via adjustable blades. A well-known example of this is the so-called Schottel ship propeller. This type of pump then has only one rotor whose direction of rotation is maintained constant. The mechanical adjustment of the angle of attack of the rotor blades results in a reversal of the conveying direction. Similar to the valve technology, this procedure is only possible with spatially extended systems, as the blade adjustment must be designed robust and this requires a mechanism is required. Likewise, this system is therefore difficult to miniaturize. The mechanics used is subject to increased wear depending on the number of cycles required. The arrangement described in CN 2688942 has adjustable guide vanes with intricately designed mechanics.

The object of the invention is to provide a fluidic pump device which has a long service life.

The object is achieved by a pumping device according to claim 1 or 6.

A first preferred embodiment of the pumping device has two separately driven rotor elements. It is particularly preferred to provide two separate drives, so that in particular the speed of the two rotor elements can be controlled independently of each other in a simple manner. By providing two, in particular powerful electric motors, the structure of such a pump device can be significantly simplified. Modern electric motors have, in addition to a high power density, high efficiency and a long service life.

Each of the two rotor elements provided according to the invention has a plurality of conveying elements such as rotor blades. By the conveying elements are Conveying surfaces are formed, which exert a force on the medium to be conveyed due to the rotation of the rotor elements and cause a conveying of the medium. According to the invention, it is possible to change the position of the conveying elements of the first rotor element relative to the conveying elements of the second rotor element. Depending on the position of the conveyor elements to each other different conveyor surfaces are active. As a result, when, for example, the conveying surfaces of the conveying elements of the first rotor element are active, fluid flows in a conveying direction, and when the conveying surfaces of the conveying elements of the other rotor element are active, the fluid flows in the opposite direction. This can be achieved in particular by the fact that, for example, with the same direction of rotation of the two rotor elements, depending on the flow direction, the first rotor element lags the second rotor element or vice versa.

According to the invention, it is thus possible to change the flow direction of the fluid pumped by the pump device without changing the direction of rotation of the rotor elements. Only the offset of the two rotor elements to each other must be changed. This can be achieved in a simple manner in that one of the rotor elements is rotated faster or slower than the other rotor element in the short term, and then the two rotor elements rotate again at the same rotational speed. As a result, a change in the offset and thus a change in the flow direction is realized in that other conveying surfaces of the conveying elements are at least mainly active. Also, the conveying surfaces of the different conveying elements together depending on the position together each form a conveying surface with a different contour, so that in this way the flow direction can be changed. In this preferred embodiment of the pumping device is thus in particular an axial pump, wherein a varying of the conveying direction is realized by a phase difference or changing the offset between the conveying surfaces. In particular, it is possible to use such a pump as a check valve. This is done by periodically changing the offset between the two rotor elements. This causes a periodic change of the flow direction. At a relatively high frequency of change, the pump thus acts as a check valve. The blocking effect can also be achieved if the conveying surfaces of the rotor elements are brought into the outermost Kontraposition, so have the greatest distance from each other. In this case, it is sufficient to turn at a higher speed, thus increasing the flow resistance through the pump and achieving a blocking effect. Here, the two active surfaces of the conveying elements are arranged in a position in which neither of the two active surfaces has a preferred conveying direction.

In a particularly preferred embodiment, the conveying elements of the two rotor elements overlap in the axial direction at least partially. In order to form an optionally common conveying surface, it is preferable for the conveying elements to abut one another and, to that extent, for there to be a contact surface between the two conveying elements. In this case, it is possible that, for example, the conveying elements of a first of the two rotor elements bear against the direction of rotation of the two rotor elements in a side facing away from the direction of rotation or facing the direction of rotation of the conveying elements of the other or second rotor element. The conveying elements of the first rotor element thus rush to or ahead of the conveying elements of the second rotor element. The contact surfaces on which abut the conveying elements against each other are preferably formed congruent to each other, so that a flat sealing abutment of the two conveying elements is ensured.

It is particularly preferred that in particular two drive motors, which are each connected to one of the two rotor elements, are arranged in a correspondingly hydro- or aerodynamically designed housing, so that it can be integrated directly into the fluid flow. This has the advantage that the drive shaft of the motors can be connected directly to the rotor elements.

A second preferred embodiment of the pumping device also has two separately drivable rotor elements, which are in turn driven in a preferred embodiment, two separate drive motors, in particular electric motors. In this pumping device, which is an alternative structure of the axial pump, changing the conveying direction, i. the changing of the flow direction of the fluid realized by the fact that the relative rotational speed of the two rotor elements is changed to each other. According to the invention, there is no reversal of the direction of rotation of one or even both rotor elements, but only a change in the relative speed of the two rotor elements relative to one another. For example, a first rotor elements is rotated faster than the second rotor element, whereby a conveying in one direction, for example, takes place axially from left to right. By changing the relative speed by the second rotor element is rotated faster than the first rotor element, there is a reversal of the conveying direction, for example, a conveying of the fluid axially from right to left. The conveying surfaces of the conveying elements are in this case designed such that depending on the relative rotational speed different conveying surfaces are active and thus in particular cause a conveying of the fluid axially to the right or left.

It is particularly preferred that one of the two rotor elements at least partially surrounds the other rotor element. In particular, the two rotor elements are arranged coaxially with each other. In preferably substantially cylindrically configured rotor elements, one rotor element can completely surround the other. Depending on the direction of conveyance, the inner rotor element therefore rotates faster or slower than the outer rotor element. In this preferred embodiment, it is preferred that the outer rotor element on its inner side first active surfaces, in particular Having cavities which cooperate with provided on the outside of the inner rotor element second active surfaces, in particular cavities. These cavities form the conveying surfaces, so that, depending on the relative rotational speed of the two rotor elements, mutually different conveying surfaces are active or active. In particular, depending on the conveying direction, the fluid is conveyed from the first into the second cavities or from the second into the first cavities. For example, the fluid is sucked in by the first cavities and conveyed into the second cavities. The second cavities then eject the fluid. With a corresponding change in the relative rotational speed, a reverse conveying of the fluid takes place.

In a further particularly preferred embodiment, both the first and the second cavities are formed such that they extend in the axial direction of the rotor elements only over part of the axial width of the rotor elements. None of the cavities is thus continuous in the axial direction. This initially has the advantage that a defined conveying takes place from the first cavities into the second cavities or vice versa.

In the case of axially non-continuous cavities, which preferably also have a certain distance from one another in the circumferential direction, it is also possible to arrange the first and second cavities in such a way that there is no connection between the cavities. In such an arrangement of the first cavities on the gap to the second cavities, the two rotor elements form a check valve.

Also in this preferred embodiment of the pumping device, which is in particular an alternative form of an axial pump, in particular the two drive motors are in turn arranged within the fluid flow, so that a compact construction is realized. In both embodiments described above, it is preferable to provide a highly dynamic control. This is possible by arranging in particular two flow or pressure sensors in the fluid flow. These are preferably integrated in the drive units facing away from the rotor sides. When using pressure sensors, it is possible, for example, to deduce the current volume flow via the pressure difference and speed difference. Such a central arrangement of the sensors considerably reduces the latency for a control and thus also increases the accuracy.

An essential advantage of the two embodiments of the pump device according to the invention is that no change in the direction of rotation of the rotor elements must be made to change the conveying direction of the fluid. Preferably, regardless of the change in the direction of the volume flow, only the two rotor elements move. This has the consequence that the life of the bearings is significantly increased. Furthermore, it is possible that both rotor elements are accelerated after starting to a sufficiently high speed, so that for example in bearings designed as a sliding bearing, a hydrodynamic lubrication takes place. As a result, the wear can be minimized. For applications with high safety requirements or high reliability, the pump device can continue to promote the medium in both directions if one of the two rotor elements fails. This can be done by the fact that the remaining rotor element changes its direction of rotation with a change of the conveying direction and thus can cause the same pumping mechanisms as in the previously described speed difference.

Since in the pumping devices according to the invention changing the flow direction takes place either by changing the phase position of the rotor elements to each other or by changing the relative rotational speed of the rotor elements to each other, is also the provision of valves and complex mechanical devices not required for changing the conveying direction. In particular, a continuous change of the flow direction is possible by the pump devices according to the invention. In known mechanical devices is often a discrete setting of the valves. This has high pressure surges in the fluid circuit result, which burden the pumping device, in particular the bearings. By a continuous change of the conveying direction is a targeted damping of such pressure surges. The switching process can take place dynamically in the pumps according to the invention. In this respect, it is possible to adapt the switching process to the prevailing pressure or flow environment. This is not possible with discrete valves or adjustable blade angles.

Optionally, in the pump devices according to the invention, in particular in the case of the radial pump, the effect may occur that the rotor rotating at a lower rotational speed is accelerated by the rotor rotating at a faster rotational speed. In this respect, a deceleration of the slower rotor must be done. This can be done in a simple manner by the electric motor connected to this rotor element. The electric motor can be operated here as a generator, so that an energy recovery is possible. As a result, the efficiency of the pump can be further improved.

Since two drive motors are used in a preferred embodiment, the pump device according to the invention can also be used in high-security applications, since the risk of failure of the entire pump device is avoided due to this redundancy. The pumping device can also be operated with a motor, at least in a kind of emergency operation. If an engine fails, the flow direction can still be changed by reversing the direction of rotation of the rotor. In particular, due to the high reliability and the redundancy of the pump device according to the invention, these can also be used in medical technology. For example, the invention Pumping devices for highly integrated hydraulic drives, such as used in artificial arm, hand or leg prostheses.

The invention will be explained in more detail with reference to a preferred embodiment with reference to the accompanying drawings.

Show it :

Figures 1 to 3 schematic diagrams of an axial pump in different

Funding conditions

FIG. 4 shows a schematic perspective view of the two rotor elements of a further axial pump device in disassembled state,

Figure 5 is a schematic perspective view of the two rotor elements of another axial pumping device in the assembled state, and

Figure 6 is a schematic perspective view of a

Section of a cavity of an inner rotor element, the pumping device shown in Figures 4 and 5.

In a first embodiment (FIGS. 1 to 3), which is a schematic representation of a pump device for axial pumping of fluid, two rotor elements 10, 12 are provided. The rotor elements each have substantially axially extending conveying elements 14, 16, which are designed as blades. In the illustrated embodiment, the conveying elements overlap completely in the axial direction. In this respect, depending on the position of the conveying elements to each other different conveying surfaces are active. In Figure 1, both rotor elements 10, 12 with the same Turned counterclockwise rotation speed. The main surface, through which a conveying of the fluid takes place, is thus in each case the conveying surface 18 of the conveying elements 14. In this way, in the illustrated embodiment, as shown by the arrows 20, conveying the fluid in the lower view of Figure 1 from left to right.

In order to change the conveying direction, either the rotor 10 is accelerated in the short term or the rotor 12 braked short term. As a result, the two rotors 10, 12 reach the position shown in FIG. 3 via the intermediate position shown in FIG. The direction of rotation of the two rotors counterclockwise remains. The delivery of the fluid now takes place through the conveying surfaces 22 of the conveying elements 16. Due to the embodiments of the conveying surfaces, the conveying of the fluid takes place in the opposite direction, ie. in the direction of the arrows 24 in the lower representation of Figure 3, from right to left, with no change in the direction of rotation takes place.

Since, in the embodiment of the pumping device shown in FIGS. 1 to 3, the two rotor elements 10, 12 always rotate in the same direction, it is also conceivable that only the rotor lagging relative to the direction of rotation is driven. In the position shown in Figure 1, it would thus be sufficient if the rotor element 12 is driven. In the position shown in Figure 3, it would be sufficient if the rotor element 10 is driven.

In the second preferred embodiment of the pumping device (FIGS. 3 to 5), which is a radial pump, two rotor elements 30, 32 are also provided. These rotor elements are essentially cylindrical rotor elements which are arranged coaxially with one another. The inner rotor element 30 is in this case preferably surrounded by the outer rotor element 32. The conveying direction of this pumping device depends on the relative rotational speed of the two rotor elements 30, 32 from each other, the direction of rotation always remains unchanged. In a counterclockwise direction of rotation (FIG. 5), the fluid accelerates through the edges or regions 34 of the active surfaces or cavities 36 and deflects the fluid through the edges or regions 38. The cavities of the inner Rotor element 30 are in this case provided on an outer side 40 of the rotor element 30 and do not extend over the entire axial width of the rotor element 30. The cavities 36 are as shown in Figure 5, left open and closed to the right.

Cavities are also provided in the outer rotor element 32. The corresponding active surfaces or cavities 42 (FIG. 3) are arranged on the inner side 44 of the cylindrically shaped outer rotor element 32. The cavities 42 likewise do not extend over the entire axial width of the rotor element 32, but are open only in one direction. In particular, it can be seen from FIGS. 3 and 4 that the openings of the cavities 36, 42 are directed oppositely. Depending on the relative rotational speed of the two rotor elements 30, 32 to each other, for example, a suction of the fluid from the inner cavities 36, a conveying of the fluid from the inner cavities 36 in the outer cavities 42 and then out of the openings of the outer cavities 42 out. With a corresponding change in the relative rotational speed to one another, the fluid is conveyed in the opposite direction.

Claims

claims

1. Pumping device with two separately drivable rotor elements (10, 12), which together cause a conveying of the medium by rotation of the rotor elements, wherein each rotor element (10, 12) at least one conveying element (14, 16), wherein by the conveying elements (14 , 16) conveying surfaces (18, 22) are formed, which promote the medium in one or the other conveying direction, and wherein a position of the conveying elements (14, 16) is variable relative to each other, and depending on the position of the conveying elements (14, 16) mutually different conveying surfaces (18, 22) are active.

2. Pump device according to claim 1, characterized in that, depending on the position of the conveying elements (14, 16) to each other, the conveying direction (20, 24) changes, the direction of rotation, in particular both rotor elements (14, 16) always remains unchanged.

3. A pump device according to claim 1 or 2, characterized in that the conveying elements (14) of a first of the two rotor elements (14) in a first conveying direction (20) on a side facing away from the direction of rotation of the conveying elements of the second of the two rotor elements (16) ,

4. Pumping device according to one of claims 1 to 3, characterized in that the conveying elements (16) of a first of the two Rotor elements (10) in a second conveying direction (24) on one of the direction of rotation facing side of the conveying elements of the second of the two conveying elements (16).

5. Pumping device according to one of claims 1 to 4, characterized in that cover the conveying elements (14, 16) of the two rotor elements (10, 12) at least partially in the axial direction.

6. Pumping device according to one of claims 1 to 5, characterized in that at short-term changing the position of the conveying elements (14, 16) to each other or in an arrangement of the active conveying surfaces at a maximum distance, the pumping device acts as a check valve.

7. Pumping device with two separately driven rotor elements (30, 32), wherein each rotor element (30, 32) a plurality of conveying elements (36, 42), wherein by the conveying elements (36, 42) conveying surfaces (34, 38) are formed, and wherein a relative rotational speed of the two rotor elements (30, 32) is mutually variable and depending on the relative rotational speed of the two rotor elements (30, 32) mutually different conveying surfaces (36, 38) are active.

8. A pump device according to claim 7, characterized in that in a first conveying direction, a first of the two rotor elements (30) rotates faster than a second of the two rotor elements (32) and that in a second conveying direction, the second of the two rotor elements (32) rotates faster than the first of the two rotor elements (30).

9. Pumping device according to claim 7 or 8, characterized in that one of the two rotor elements (32) surrounds the other of the two rotor elements (30).

10. Pumping device according to claim 9, characterized in that an outer rotor element (32) on its inner side (44) has first active surfaces (42) and the inner rotor element (30) on its outer side (46) second active surfaces (36).

11. A pumping device according to claim 10, characterized in that, depending on the conveying direction, fluid passes from the first active surface (42) into the second active surface (36) or from the second active surface (36) into the first active surface (44).

12. A pumping device according to claim 10 or 11, characterized in that the first and second active surfaces (36, 42) extend in the axial direction only over part of the axial width of the rotor elements (30, 32).

13. Pumping device according to one of claims 7 to 11, characterized in that at a relative rotational speed of zero and the greatest possible distance of the active surfaces 36, 42 of both rotor elements (10, 12, 30, 32) to each other, the pumping device acts as a check valve.

14. Pumping device according to one of claims 1 to 13, characterized in that the rotor elements (10, 12, 30, 32) are each connected to the separate drive with a drive motor.