Compressors and methods for operating a compressor

Abstract

The invention relates to compressors with a housing in which at least one impeller is rotatably mounted about an axis of rotation via a shaft by means of at least one bearing device and is driven by an electric motor drive to compress a gaseous medium. To improve the compressor in terms of manufacturing technology and / or functionality, a cooling air supply device (30) is provided for supplying at least one compressor component (4) to be cooled with cooling air from a compressor environment (7), wherein the cooling air supply device (30) comprises a cooling air conveying device (3) which is positioned upstream of the compressor component (4) to be cooled in a cooling air path (6) such that the cooling air from the compressor environment (7) is conveyed into the cooling air path (6).

Description

[0001] The invention relates to a compressor having a housing in which at least one impeller is mounted rotatably about a rotational axis via a shaft with the aid of at least one bearing device and is driven by an electric motor to compress a gaseous medium. The invention further relates to a method for operating such a compressor. State of the art

[0002] From the German patent application DE 10 2018 201 162 A1 a turbomachine, in particular for a fuel cell system, with a compressor, a drive device and a shaft is known, wherein the compressor has an impeller arranged on the shaft, a compressor inlet and a compressor outlet, wherein a working fluid can be conveyed from the compressor inlet to the compressor outlet, wherein a drive cooling path for cooling the drive device branches off at the compressor outlet.International patent application WO 2020 / 177941 A1 discloses a compressor having a housing in which an impeller is mounted for rotation about an axis of rotation. The impeller is driven to compress a medium with the aid of blading on an impeller front side. An axial force is exerted on the impeller, which has an impeller rear side facing a housing wall. In an impeller side space between the impeller rear side and the housing wall, a pressure prevails which causes a counter-axial force on the impeller rear side that counteracts the axial force on the impeller front side. The impeller side space is divided into partial pressure spaces by centrifugal force-effective seals. International patent application WO 2021 / 063566 A1 discloses an axial gas bearing with at least one gas bearing gap, which serves to form a load-bearing gas film between an axial bearing disk and a support surface. Disclosure of the invention

[0003] The object of the invention is to improve a compressor according to the preamble of patent claim 1 in terms of manufacturing technology and / or functionality.

[0004] The object is achieved in a compressor with a housing in which at least one impeller is mounted via a shaft with the aid of at least one bearing device about an axis of rotation and is driven by an electric motor drive in order to compress a gaseous medium, by a cooling air supply device for supplying at least one compressor component to be cooled with cooling air from a compressor environment, wherein the cooling air supply device comprises a cooling air conveying device which is arranged upstream of the compressor component to be cooled in a cooling air path such that the cooling air is conveyed from the compressor environment into the cooling air path. Upstream in this context means that the cooling air conveying device is arranged in the cooling air path upstream of the compressor component to be cooled. The cooling air conveying device is preferably equipped with a separate drive.This separate drive allows the cooling air conveying device to be advantageously controlled as needed. Through appropriate control, the cooling air conveyed by the cooling air conveying device, in particular a corresponding volumetric flow of cooling air, can be adjusted, in particular regulated, to a minimum required pressure difference. Since the cooling air is taken from the compressor environment, a greater temperature difference can be achieved than with the conventional use of compressed air to cool the compressor component. This effectively improves the cooling of the component to be cooled.

[0005] A preferred embodiment of the compressor is characterized in that the compressor component to be cooled comprises at least one bearing device and / or a stator of the electric motor drive, which is / is cooled by the cooling air conveyed from the compressor environment into the cooling air path. The bearing device advantageously comprises two radial bearings. Particularly advantageously, the bearing device also comprises an axial bearing in addition to the two radial bearings. All three bearings are advantageously effectively cooled by the cooling air from the compressor environment. Alternatively or additionally, the ambient air can be used to cool the stator. Here, too, cooling can be significantly improved compared to conventional applications.

[0006] A further preferred embodiment of the compressor is characterized in that the cooling air path has at least one connection point for at least two sub-paths, which are assigned to two compressor components to be cooled. The connection point is advantageously designed as a branch at which the cooling air path, which originates from the air conveying device, splits into the at least two sub-paths. Thus, with just one air conveying device, for example, the cooling of the bearing device and the stator can be achieved in a simple and highly effective manner.

[0007] A further preferred embodiment of the compressor is characterized in that the cooling air path on the housing has an inlet with a filter device through which the cooling air conveyed from the compressor environment into the cooling air path is filtered. The associated cleaning of the conveyed air can effectively prevent unwanted penetration of particles from the compressor environment.

[0008] A further preferred embodiment of the compressor is characterized in that the cooling air conveying device is mounted externally on the compressor housing. The cooling air conveying device is advantageously arranged at a cooling air inlet on the compressor housing. The cooling air conveying device at the compressor inlet represents the beginning of the cooling air path on the compressor, which extends through the compressor housing past the at least one component to be cooled and / or through the at least one component to be cooled. By mounting the cooling air conveying device externally on the compressor housing, the connection of control lines and / or the replacement of the cooling air conveying device are considerably simplified.

[0009] A further preferred embodiment of the compressor is characterized in that the cooling air conveying device is connected to a controller for control purposes. The cooling air conveying device can advantageously be controlled separately via the controller. Thus, the cooling of the component to be cooled in the compressor can be controlled or regulated as needed.

[0010] A further preferred embodiment of the compressor is characterized in that at least one sensor device is assigned to the cooling air path, with the aid of which a temperature, a pressure, and / or a volume flow in the cooling air path is detected. This allows the quality of the control or regulation, in particular for the demand-dependent provision of cooling air in the compressor, to be further improved.

[0011] In a method for operating a compressor described above, the above-mentioned object is achieved alternatively or additionally by cooling the compressor component to be cooled with cooling air from the compressor environment during operation of the compressor. This provides the particular advantage that relatively cool air can be used for cooling. The air in the compressor environment is generally significantly cooler than the air available on a pressure side of the compressor during operation. After the air from the compressor environment has been used to cool the compressor component to be cooled, this cooling air is discharged back to the compressor environment through at least one outlet.At the outlet or at several outlets, the provision of a valve device, for example in the form of a flap valve, could be advantageous in order to prevent an undesirable backflow or an undesirable penetration of substances from the compressor environment into the cooling air path.

[0012] A preferred embodiment of the method is characterized in that a cooling air volume flow conveyed through the cooling air path by means of the cooling air conveying device is adjusted to a minimum required demand in order to minimize a maximum required pressure difference. For this purpose, the cooling air conveying device is regulated to a maximum required pressure difference by means of the separate cooling air conveying device, preferably via the previously described control system, in order to increase the driving temperature difference.

[0013] The invention further relates to a housing and / or a cooling air conveying device for a compressor as described above. The housing and the cooling air conveying device are sold separately.

[0014] The invention may also relate to a fuel cell system having an electrically driven compressor as described above, which preferably serves as an air compressor for providing compressed air in the fuel cell system.

[0015] Further advantages, features and details of the invention will become apparent from the following description, in which various embodiments are described in detail with reference to the drawing. Short description of the drawing

[0016] They show: Fig. 1 a schematic representation of a cooling air path in a compressor; Fig. 2 shows a half-section through the compressor; and Fig. 3 a perspective view of the compressor. Description of the embodiments

[0017] In Fig. Figure 3 shows a perspective view of a compressor, also generally referred to as a gas delivery device 23. The gas delivery device 23 is designed as an air supply device, in particular as an air compressor. The air compressor 23 serves to provide compressed air in a mobile fuel cell system. The mobile fuel cell system, in turn, serves to provide electrical energy in a motor vehicle equipped with the fuel cell system, which is converted, for example, via an electric motor into drive energy for the motor vehicle.

[0018] The air supply device 23 comprises a multi-part housing 24 with an air connection 25 through which air is supplied, and with an air connection 26 through which compressed air is discharged. For compressing the air, the air supply device 23 comprises, for example, a compressor wheel that is rotatable within a compressor volute.

[0019] The compressor wheel is driven by an electric motor located in the housing 24. The electric motor comprises a rotor that rotates within a stator. The stator of the electric motor includes a power connection 27, via which three-phase alternating current is supplied to the stator.

[0020] In Fig. 1 is a cooling air path 6 through a Fig. 2 is shown schematically in half section. The compressor 10 is, for example, an air supply device which is described with reference to Fig. 3 is also generally referred to as gas conveying device 23.

[0021] The cooling air path 6 comprises an inlet 1, a filter device 2, a cooling air conveying device 3, a compressor component 4 to be cooled and an outlet 5. Air for cooling is sucked in from a compressor environment 7 via the inlet 1 and the filter device 2 with the aid of the cooling air conveying device 3.

[0022] With the aid of the cooling air conveying device 3, the air sucked in from the compressor environment 7 is guided past the compressor component 4 to be cooled and / or through the compressor component 4 to be cooled, before the air is then fed back into the compressor environment 7 via the outlet 5.

[0023] The Fig. The cooling air path 6 shown in Figure 1 serves in the Fig. 2 to illustrate a cooling air supply device 30 with which the compressor component 4 to be cooled can be effectively cooled with air from the compressor environment 7 during operation of the compressor 10.

[0024] In the Fig. In the compressor 10 shown in half section in Figure 2, the inlet 1 can also be combined with the filter device 2. The compressor 10 comprises a housing 11 in which an electric motor drive 19 with a stator 20 is housed.

[0025] The stator 20 interacts in a known manner with a rotor which is connected in a rotationally fixed manner to a shaft 13. At a Fig. 2 An impeller 12, indicated only by a reference symbol, is attached to the left end of the shaft 13. The impeller 12 is a compressor wheel. Fig. 2 A turbine wheel can be attached to the right end of the shaft 13.

[0026] The shaft 13 is rotatably mounted in the housing 11 by means of a bearing device 14. The bearing device 14 comprises two radial bearings 15, 16 and one axial bearing 17 for radial and axial support of the shaft 13 in the housing 11. The shaft 13 is rotatable about a rotational axis 18. The terms "radial" and "axial" refer to this rotational axis 18. "Axial" means in the direction of or parallel to the rotational axis 18. "Radial" means perpendicular to the rotational axis 18.

[0027] In Fig. Figure 2 shows that the cooling air conveying device 3 is mounted externally on the housing 11 of the compressor 10. The cooling air conveying device 3 comprises, for example, a fan wheel driven by its own drive. Depending on the drive design, the fan wheel can be driven at a constant speed.

[0028] However, it is particularly advantageous if the drive of the cooling air conveying device 3 is controlled by a separate controller 38. The controller 38 can also be integrated into a compressor controller. The cooling air conveying device 3 can advantageously be controlled as needed via the controller 38.

[0029] The cooling air supply device 30 comprises fluid channels that represent the cooling air path 6 between the inlet 1 and the outlet 5 in the housing 11 of the compressor 10. The cooling air path 6 comprises at least one connection point in the housing 11.

[0030] The course of the fluid channels with the connection point in the housing 11 of the compressor 10 is shown in Fig. 2 by arrows 31 to 37. The course of the cooling air path 6 in the compressor housing 11 indicated by arrows 31 to 37 is, of course, only an example.

[0031] Arrow 31 illustrates a cooling air volume flow that is drawn in at the inlet 1 via the filter device 2 by the cooling air conveying device 3. The cooling air conveying device 3 is arranged together with the filter device 2 at the inlet 1 of the compressor housing 11.

[0032] The arrow 32 illustrates in Fig. 2, how the cooling air volume flow is pushed radially inward into the compressor housing 11 by the cooling air conveying device 3. Arrows 33 and 34 illustrate how the cooling air volume flow is divided into two partial paths.

[0033] The partial path 34 runs in the axial direction in Fig. 2 to the right. Thus, the cooling air in this partial path 34 can supply both the stator 20 and the radial bearing 16 with cooling air before the cooling air in Fig. 2 right from the compressor 10 back into the compressor environment 7, as in Fig. 2 is illustrated by the arrow 35.

[0034] The partial path 33 of the cooling air path 6 runs as in Fig. 2 is illustrated by the arrow 36, initially in the axial direction in Fig. 2 to the left and then radially outward. Thus, the cooling air can be used via partial path 33 both to cool the radial bearing 15 and to cool the axial bearing 17, before the cooling air is then discharged radially outward at the outlet 5 back into the compressor environment 7, as illustrated by arrow 37.

[0035] In addition to the optional control 38, the cooling air supply device 30 also comprises at least one sensor device 39, which Fig.2 is arranged near the cooling air outlet 5. The sensor device 39 comprises, for example, a temperature sensor, a pressure sensor, and / or a volume flow sensor. The sensor device 39 is connected to the controller 38 for control purposes. This optimizes the demand-dependent control of the cooling air conveying device 3. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2018 201 162 A1

[0002] WO 2020 / 177941 A1

[0002] WO 2021 / 063566 A1

[0002]

Claims

[1] Compressor (10) with a housing (11) in which at least one impeller (12) is rotatably mounted about an axis of rotation (18) via a shaft (13) with the aid of at least one bearing device (14) and is driven by an electric motor drive (19) in order to compress a gaseous medium, characterized by a cooling air supply device (30) for supplying at least one compressor component (4) to be cooled with cooling air from a compressor environment (7), wherein the cooling air supply device (30) comprises a cooling air conveying device (3) which is arranged upstream of the compressor component (4) to be cooled in a cooling air path (6) such that the cooling air is conveyed from the compressor environment (7) into the cooling air path (6). [2] Compressor according to claim 1, characterized bythat the compressor component (4) to be cooled comprises at least one bearing device (14) and / or a stator (20) of the electric motor drive (19), which is / are cooled by the cooling air conveyed from the compressor environment (7) into the cooling air path (6). [3] Compressor according to one of the preceding claims, characterized by that the cooling air path (6) has at least one connection point for at least two partial paths (33, 34) which are assigned to two compressor components (4) to be cooled. [4] Compressor according to one of the preceding claims, characterized by that the cooling air path (6) on the housing (11) has an inlet (1) with a filter device (2) through which the cooling air conveyed from the compressor environment (7) into the cooling air path (6) is filtered. [5] Compressor according to one of the preceding claims, characterized bythat the cooling air conveying device (3) is mounted externally on the housing (11) of the compressor (10). [6] Compressor according to one of the preceding claims, characterized by that the cooling air conveying device (3) is connected for control purposes to a controller (37). [7] Compressor according to one of the preceding claims, characterized by that at least one sensor device (39) is assigned to the cooling air path (6), with the aid of which a temperature, a pressure and / or a volume flow in the cooling air path (6) is detected. [8] Method for operating a compressor (10) according to one of the preceding claims, characterized by that the compressor component (4) to be cooled is cooled with cooling air from the compressor environment (7) during operation of the compressor (10). [9] Method according to claim 8, characterized bythat a cooling air volume flow (31, 32) conveyed through the cooling air path (6) with the aid of the cooling air conveying device (3) is adapted to a minimum necessary requirement in order to minimize a maximum required pressure difference. [10] Housing (11) and / or cooling air conveying device (3) for a compressor (10) according to one of claims 1 to 7.

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