Noise-optimized system for driving a centrifugal pump

Abstract

The invention relates to a system (1) for driving a centrifugal pump (2), said system (1) having at least one cooling assembly (6, 23) which comprises cooling ribs (7). The cooling ribs (7) are arranged in rows at a distance to one another, and the cooling assembly (6) comprises a structure (11) for reducing noise, wherein the structure (11) has fixation elements (12) at the free ends of the cooling ribs (7).

Description

[0001] Description

[0002] Noise-optimized system for driving a centrifugal pump

[0003] The invention relates to a system for driving a centrifugal pump, wherein the system has at least one cooling arrangement comprising cooling fins, wherein the cooling fins are arranged in rows at a distance from one another.

[0004] A centrifugal pump typically includes a drive system, usually comprising one or more electric motors and power electronic devices for speed control via frequency conversion. The electric motors and the associated motor electronics, in particular, require adequate cooling during operation.

[0005] An electric motor consists of a rotor that is connected to the motor shaft in a rotationally fixed manner, a stator with a wound stator package, a stator housing with cooling fins on the outside, bearing shields on both sides with rolling or plain bearings and optionally a fan wheel that is connected to the shaft on the shaft end opposite the drive side in a rotationally fixed manner and can be enclosed by a fan cover that is firmly connected to the stator housing.

[0006] DE 10 2021 000 933 A1 discloses a pump comprising a drive motor, at least one electronics housing and at least one heat sink for dissipating heat from the electronics housing, wherein an intermediate piece for thermally decoupling the heat sink from the motor housing is inserted between the heat sink and the motor housing of the drive motor.

[0007] DE 10 2021 108 359 A1 describes an electric motor for driving a centrifugal pump with a cooling arrangement. The cooling arrangement comprises a fan impeller and a hood, with the hood enclosing a space. Guide elements are arranged within the space.

[0008] DE 10 2021 005 031 A1 discloses a heating circulation pump with at least one electronics housing for the pump electronics, wherein the electronics housing is composed of at least two housing parts with an integrated heat sink and at least one sealing element is inserted in the connecting gap between the at least two housing parts.

[0009] Centrifugal pumps, and thus also the electric motors used to drive them, are sometimes used in noise-sensitive areas, such as hospitals, kindergartens, schools, and even private households. One area of ​​application is the conveyance of fluids in heating or cooling systems. It is desirable and desirable to keep the noise and sound pressure levels of the motors and pumps as low as possible.

[0010] Some pump series already feature centrifugal pumps optimized for noise reduction. To achieve even lower sound pressure levels, the components adjacent to the pump, such as the cooling system, must also be optimized. At certain frequencies, for example, the ends of the cooling fins of a cooling system can move, emitting corresponding sound waves.

[0011] The structure of the cooling fins of a cooling system itself can be susceptible to resonance phenomena, especially if they are not securely mounted or sufficiently damped. If the frequency of the exciting forces from the motor, power electronics, or pump matches the natural resonant frequency of the cooling fins, the vibrations are amplified, which can lead to loud noises.

[0012] In addition, cooling systems are equipped with fans that pull air through the cooling fins to dissipate heat. If these fans are not well balanced or if they show signs of wear, they can generate additional vibrations. Vibrations can also be caused by the uneven rotation of the fan blades and can be perceived as a humming or buzzing sound.

[0013] The object of the invention is to provide a system for driving a centrifugal pump with a cooling arrangement that can operate with particularly low noise and at a low sound pressure level. The cooling arrangement should be able to reliably dissipate the heat generated during system operation and when pumping hot fluids. Furthermore, the cooling arrangement should be characterized by a compact design. The cooling arrangement should be simple and cost-effective to implement.

[0014] This object is achieved according to the invention by a system for driving a centrifugal pump with a cooling arrangement according to the features of claim 1. Preferred variants can be found in the independent main claims, the subclaims, the description and the drawings.

[0015] According to the invention, the cooling arrangement comprises a structure for noise reduction, wherein the structure has fixing elements at the free ends of the cooling fins.

[0016] For example, the system consists of an electric motor and power electronics to drive a centrifugal pump.

[0017] The cooling arrangement can, for example, be arranged between the pump housing of the centrifugal pump and the electric motor.

[0018] In a further variant of the invention, the cooling arrangement can be arranged between the electric motor and a box or power electronics box for controlling the electric motor. The cooling arrangement according to the invention has a plurality of cooling fins. For example, the cooling fins are arranged in rows spaced apart from one another.

[0019] Preferably, the cooling fins are aligned and arranged parallel to each other.

[0020] For example, the cooling fins are designed as flat cuboids standing on a base plate.

[0021] The base plate is made of a heat-conducting material, for example, and preferably has contact with the electric motor and / or the power electronics.

[0022] In a variant of the invention, the base plate has a height that corresponds to the thickness of the cooling fins.

[0023] In a variant of the invention, the spacing of the cooling fins is more than three times the thickness, preferably more than four times the thickness, in particular more than five times the thickness, and / or is less than eight times the thickness, preferably less than seven times the thickness, in particular less than six times the thickness, of the cooling fins.

[0024] For example, each cooling fin tapers from the bottom to the top. This means that the thickness decreases across the entire height of the cooling fin. This can be advantageous for molding cast cooling assemblies, while simultaneously reducing vibration of the cooling fins. This is particularly beneficial for reducing system noise during centrifugal pump operation.

[0025] The free ends of the cooling fins are preferably visible on the side remote from or facing away from the base plate and form, for example, the upper end of the cooling fins. Therefore, the upper end of the cooling fin is the part that exhibits the greatest vibrational potential due to its distance from the base plate. According to the invention, the cooling arrangement comprises a structure for noise reduction, wherein the structure has, for example, web-like connections.

[0026] The structure comprises at least one web-like connection or can consist of a network of interconnected web-like connections that position the free ends of the cooling fins relative to each other. The structure can, for example, be plugged on, or retrofitted to an already operating system for driving a centrifugal pump, or be permanently connected to the cooling arrangement as a single piece. Furthermore, the structure itself can be formed as a single piece or consist of unconnected individual elements.

[0027] In one variant of the invention, the structure is designed as a separate part that is plugged onto the cooling fins of the cooling assembly. This design variant is ideal for reducing the noise of existing, already in-use systems for driving centrifugal pumps, whereby the structure can be easily plugged onto the cooling assembly at a later date.

[0028] In a further variant of the invention, the structure is integrated into the cooling arrangement. This is not a loose, attached design, but rather a permanently integrated and non-detachable structural variant.

[0029] For example, the structure is formed integrally with the cooling arrangement. In this case, the structure is preferably formed integrally with the cooling arrangement, for example through a generative manufacturing process or through a primary forming manufacturing process. In this design variant, the structure keeps the cooling fins at defined distances from one another and, due to the almost rigid design, e.g. of the webs of the structure, reliably reduces any oscillating movement of the individual cooling fins, thereby effectively reducing the noise emanating from the system. In a special variant, the structure is formed from unconnected, individual elements. The individual elements are distributed over the cooling arrangement in such a way that they prevent the cooling fins from oscillating at the free ends for passive noise reduction.The elements can, for example, extend from one cooling fin to the adjacent cooling fin or even across several cooling fins.

[0030] The web-like connections and / or elements of the structure can be made of the same material as the cooling arrangement.

[0031] In an alternative variant, the web-like connections and / or elements of the structure are made of a plastic.

[0032] In a variant of the invention, the web-like connections have a width which is more than 70%, preferably more than 85%, and / or less than 400%, preferably less than 200%, of the thickness of the cooling fins.

[0033] For example, the web-like connections of the structure have a height that is more than 70%, preferably more than 85%, and / or less than 200%, preferably less than 120%, of the thickness of the cooling fins.

[0034] In one variant of the invention, the web-like connections of the structure are arranged orthogonally to the cooling fins. The webs thus provide a defined spacing between the cooling fins and stiffen the free ends of the cooling fins, thereby advantageously reducing vibration and thus the possibility of noise generation.

[0035] For example, the webs of the structure are arranged at equal distances from each other. This means that all cooling fins are equally restricted in their vibration by the structure's fixation. In an alternative variant, the cooling fins are at least partially formed as a corrugated plate standing on a base plate. This design is advantageous for passive noise reduction of the cooling arrangement.

[0036] For example, the cooling arrangement is integrated as part of the electric motor housing.

[0037] In one variant, the cooling arrangement is formed in one piece with the electric motor housing.

[0038] In an alternative variant, the cooling arrangement is mounted flush with the electric motor housing.

[0039] In a further variant of the invention, the cooling arrangement is connected to a power electronics system. For example, the components of the power electronics can be connected flush with the cooling arrangement.

[0040] In an alternative variant, the cooling arrangement is formed in one piece with the power electronics box.

[0041] In a variant of the invention, the cooling arrangement is formed in one piece.

[0042] In an alternative variant of the invention, the base plate of the cooling arrangement is cylindrical. For example, the cooling fins are arranged in a star shape on the base plate and / or in rows in a star shape and / or parallel to one another. For example, the cylindrical cooling arrangement is advantageous when the cooling arrangement is designed as a single piece with the electric motor housing.

[0043] In one variant of the invention, the rows of cooling fins on the cylindrical base plate are straight. For example, the rows are aligned parallel to each other. For example, the cooling arrangement can also include a fan for active cooling. The design of the vertical profile of the cooling fins advantageously reduces noise generation, allowing the system to drive a centrifugal pump even in noise-sensitive areas.

[0044] In one embodiment of the invention, the cooling arrangement, in particular the one-piece structure of the cooling arrangement, is produced by a method in which the cooling arrangement with the cooling fins including the recesses for passive noise reduction is produced by selectively exposing energetic radiation to layers of powder applied in layers.

[0045] Selective laser melting (SLM) is an additive manufacturing process used to produce the cooling fins of the cooling assembly as a one-piece structure from metal powder, particularly aluminum or copper powder. It is a form of 3D printing in which a high-power laser is used to selectively melt the powder and build up the base plate and cooling fins layer by layer.

[0046] The base plate and fins of the cooling assembly are built layer by layer by applying a thin layer of powder to a build platform. The laser beam is then directed at the selected areas, where it melts the metal powder and bonds it into a solid layer. A new layer is then applied, and the process is repeated until the cooling assembly is complete.

[0047] Preferably, a high-power laser, typically a fiber laser or a CO2 laser, is used. The laser beam is precisely controlled to melt and fuse the metal powder. The laser parameters such as power, intensity, and speed are adjusted according to the requirements of the process and the selected material, especially a metallic material. For example, the laser parameters can also be partially adjusted to create defined and desired microstructures. After additive manufacturing, the cooling arrangement can possibly be post-processed, for example, to achieve flat surfaces for the cooling fins and / or a smooth shape for the height profile.

[0048] In an alternative variant of the invention, the cooling assembly can also be manufactured using a casting process. The cooling assembly with the structure is formed, for example, as an aluminum die-cast.

[0049] For example, the cooling arrangement is constructed entirely from the same and identical material.

[0050] For example, the cooling fins on the side opposite the base plate have a height profile for noise reduction. The height profile can advantageously complement the noise-reducing structure.

[0051] The height profile, for example, is designed for passive noise reduction in the centrifugal pump drive system. In addition to the structure, the height profile reduces the vibrations of the cooling fins or the vibrations of the cooling fins relative to each other and / or the sound pressure level caused by the vibrations of the cooling fins.

[0052] The height profile for passive noise reduction can be achieved using cutouts at the free ends of the cooling fins. For example, the cutouts of the respective cooling fins are arranged offset from each other, within a row and / or to the next row, so that when the cooling fins vibrate relative to each other, the counterpart is at least partially absent from generating sound pressure, thus achieving passive noise reduction.

[0053] For example, a recess has a depth and a width.

[0054] In one variant of the invention, the depths and widths of the recesses can be identical for all recesses. In another variant, the depths and widths of the recesses are different for each recess.

[0055] The arrangement of the recesses, for example, forms the height profile of the cooling fin, which can achieve passive noise reduction.

[0056] For example, the height profile is periodically formed.

[0057] The word "periodic" refers specifically to the recesses that form the elevation profile, which are arranged at regular intervals or periods, or whose arrangement is repeated. The recesses that form the elevation profile are arranged at intervals or cycles.

[0058] In a further variant of the invention, the height profile of every second cooling fin of the cooling arrangement has the same geometric shape, wherein the two shapes are arranged alternately to one another.

[0059] For example, at least one height profile of the cooling arrangement is wave-shaped and / or rectangular and / or triangular and / or trapezoidal and / or sawtooth-shaped.

[0060] In a variant of the invention, the height profiles of adjacent cooling fins are designed to be phase-shifted relative to one another, wherein preferably height profiles of immediately adjacent cooling fins are designed to be phase-shifted relative to one another.

[0061] Each of the described individual designs, and especially the combination of the described designs, can reduce the vibrations of the cooling fins. For example, sound waves cancel each other out due to the design of the cooling fins. The so-called air pumping in the room caused by the movement of the cooling fins relative to each other is significantly reduced or even completely prevented, thus preventing sound and thus noise. According to the invention, the system for driving a centrifugal pump with the cooling arrangement is used with reduced noise generation in very noise-sensitive applications.

[0062] Further features and advantages of the invention will become apparent from the description of embodiments with reference to the drawings and from the drawings themselves.

[0063] It shows:

[0064] Fig. 1 shows an exemplary embodiment of the system for driving a centrifugal pump,

[0065] Fig. 2 shows an exemplary embodiment of the cooling arrangement with a structure for noise reduction,

[0066] Fig. 3 shows another variant of the cooling arrangement,

[0067] Fig. 4 an embodiment of the cooling arrangement with web-like connections,

[0068] Fig. 5 shows a further embodiment of the cooling arrangement with web-like connections,

[0069] Fig. 6 an alternative embodiment of the cooling arrangement with web-like connections,

[0070] Fig. 7 shows an embodiment of the cooling arrangement with integrated structure,

[0071] Fig. 8 an alternative embodiment of the cooling arrangement with integrated structure,

[0072] Fig. 9 shows a further variant of the system for driving a centrifugal pump, Fig. 10 shows an embodiment of the cylindrical cooling arrangement,

[0073] Fig. 11 another variant of the cylindrical cooling arrangement with web-like connections,

[0074] Fig. 12 an embodiment of the cylindrical cooling arrangement with integrated structure.

[0075] Fig. 1 shows an exemplary embodiment of the system 1 for driving a centrifugal pump 2, consisting of an electric motor 25 and power electronics 24. The modern high-efficiency pump has a suction nozzle 3 and a pressure nozzle 4, via which the centrifugal pump 2 is integrated into a piping system.

[0076] In the illustrated embodiment, the electric motor 25 is designed as a canned motor. The canned motor is a special type of wet-rotor motor in which the stator winding is protected from the conveying medium by a cylindrical, preferably thin-walled tube in the air gap of the machine.

[0077] The power electronics 24 of system 1 is located in the electronics box 5. The cooling assembly 6 is positioned at the bottom of the electronics box 5. The housing of the electric motor 25 also has a cooling assembly 23.

[0078] Figs. 2 and 3 show a cooling arrangement 6 that can be attached to the underside of the electronics box 5. The cooling arrangement 6 has fourteen cooling fins 7 that are equally spaced. The cooling fins 7 extend from a base plate 8 and taper away from the base plate 8. The thickness of the cooling fin 7 decreases over its height. The cooling arrangement 6 has a round area 9 with shortened cooling fins 7, within which two drill sleeves 10 for attachment to the electric motor 25 are arranged.

[0079] Fig. 2 shows a cooling arrangement 6 with a mounted structure 11 for noise reduction. The structure 11 extends over the edge of the cooling arrangement 6 and partially over the round area 9. With the fixing elements 12, the structure 11 positions the cooling fins 7 in their relative positions, spaced the cooling fins 7 from each other, and reduced the vibrational potential of the cooling fins 7.

[0080] Fig. 3 shows a variant of the cooling assembly 6 with an integrated structure 11 for noise reduction. In this embodiment, the structure 11 is formed integrally with the cooling assembly 6.

[0081] Figures 4 to 8 show exemplary detailed sections of different cooling assemblies 6 with a structure 11 for noise reduction. Each cooling assembly 6 has several cooling fins 7 spaced apart. The spacing of the cooling fins 7 from one another is four times the thickness of a cooling fin 7.

[0082] The cooling fins 7 are aligned and arranged parallel to each other. The cooling fins 7 are designed as flat cuboids standing on a base plate 8.

[0083] Fig. 4 shows a variant in which the structure 11 consists of several web-like connections 13, which, by means of the elements 12, fix the cooling fins 7 at a defined distance from each other and reduce their vibration potential. The web-like connections 13 are designed orthogonally to the cooling fins. The distances 14 and 15 are unequal in this variant and are adjusted according to the results of a vibration simulation.

[0084] Fig. 5 shows a variant of the web-like connections 13, which are arranged at equal spacings 16 from one another and at the edges 17 of the cooling fins 7. Fig. 6 discloses a variant of the cooling arrangement 6 in which the web-like connections 13 each position two cooling fins 7 relative to one another. In the variant shown, the noise reduction structure 11 consists of eight web-like connections 13, each offset by a spacing 18 and arranged at equal spacings 19 from one another.

[0085] Fig. 7 shows a cooling assembly 6 with an integrated noise reduction structure 11. The web-like connections 13 are formed integrally with the cooling assembly 6 and arranged at equal spacing 16.

[0086] The illustration in Fig. 8 corresponds to the illustration in Fig. 6, wherein the structure 11 for noise reduction in the illustrated embodiment is integrated into the cooling arrangement 6 and formed in one piece with it.

[0087] Fig. 9 shows a further exemplary embodiment of the system 1 for driving a centrifugal pump 2, consisting of an electric motor 25 and power electronics 24. The centrifugal pump 2 has a suction nozzle 3 and a pressure nozzle 4, via which the centrifugal pump 2 is integrated into a piping system.

[0088] In the illustrated embodiment, the electric motor 25 is designed as a motor flanged via a lantern. The power electronics 24 of the electric motor 25 is arranged in the power electronics box 5, which is positioned on the electric motor 25 at a distance from it by a cooling arrangement 6. The housing of the electric motor 25 also has a cooling arrangement 23.

[0089] Fig. 10 shows a variant of a cylindrical cooling arrangement 23. The cooling arrangement 23 has twelve cooling fins 7 that are spaced at an equal distance. The noise reduction structure 11 is pushed over the cooling fins 7 in the form of two web-like rings 20, with the fixing elements 12, which in this variant are two-part, firmly fixing the upper ends of the cooling fins 7. Fig. 11 discloses a variant of the cooling arrangement 23 in which the web-like connections 13 of the noise reduction structure 11 position two cooling fins 7 relative to one another, thereby significantly reducing their vibrational potential. The structure can be connected to the cooling fins 7, for example, by force, form, or material engagement.

[0090] The illustration in Fig. 12 essentially corresponds to Fig. 10, wherein the noise reduction structure 11 in the illustrated embodiment is integrated into the cooling arrangement 23 and formed integrally therewith. The noise reduction structure 11 is formed in the form of two web-like rings 20 formed integrally with the cooling fins 7. The rings 20 are spaced apart by a distance 21 and are at a distance 22 from the edge of the cooling arrangement, wherein the distance 22 corresponds to half the distance 21.

Claims

Patent claims Noise-optimized system for driving a centrifugal pump 1. System (1) for driving a centrifugal pump (2), the system (1) comprising at least one cooling arrangement (6, 23) comprising cooling fins (7), the cooling fins (7) being arranged in rows at a distance from one another, characterized in that the cooling arrangement (6, 23) comprises a structure (11) for noise reduction, the structure (11) having elements (12) for fixing at the free ends of the cooling fins (7).

2. System according to claim 1, characterized in that the structure (11) has web-like connections (13).

3. System according to claim 1 or 2, characterized in that the structure (11) is designed as a separate part and is plugged onto the cooling fins (7) of the cooling arrangement (6, 23).

4. System according to claim 1 or 2, characterized in that the structure (11) is integrated into the cooling arrangement (6, 23).

5. System according to claim 4, characterized in that the structure (11) is formed integrally with the cooling arrangement (6, 23).

6. System according to one of claims 1 to 5, characterized in that the web-like connections (13) have a width which is more than 70%, preferably more than 85%, and / or less than 400%, preferably less than 200%, of the thickness of the cooling fins (7).

7. System according to one of claims 1 to 6, characterized in that the web-like connections (13) of the structure (11) have a height which is more than 70%, preferably more than 85%, and / or less than 200%, preferably less than 120%, of the thickness of the cooling fins (7).

8. System according to one of claims 1 to 7, characterized in that the web-like connections (13) of the structure (11) are arranged orthogonally to the cooling fins (7).

9. System according to one of claims 1 to 8, characterized in that the web-like connections (13) of the structure (11) are arranged at equal distances from one another.

10. System according to one of claims 1 to 9, characterized in that a web-like connection (13) of the structure (11) is arranged on the edge (17) of the cooling fins (7).

11. System according to one of claims 1 to 10, characterized in that the cooling fins (7) are designed as a corrugated plate standing on a base plate (8).

12. System according to one of claims 1 to 11, characterized in that the cooling arrangement (23) is formed as part of the electric motor housing.

13. System according to one of claims 1 to 12, characterized in that the cooling arrangement (6, 23) is connected to a power electronics unit (24).

14. Use of a system (1) for driving a centrifugal pump (2) while reducing noise in very noise-sensitive application areas.

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